####018005992#### FXUS66 KMTR 032345 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 445 PM PDT Fri May 3 2024 ...New MARINE... .SYNOPSIS... Issued at 1237 PM PDT Fri May 3 2024 Cold front on track to bring widespread rain, cooler temperatures, and gusty winds this weekend. Dry weather returns Sunday with a gradual warming trend through next week. && .SHORT TERM... (This evening through Saturday) Issued at 1237 PM PDT Fri May 3 2024 Mostly clear skies over the region today ahead of the next cold front. Ample cloud cover associated with the front now moving into the northern portions of the state will continue to move southward through tonight. Areas of light rainfall are expected to begin early Saturday morning along favored west-facing upslope areas in the coastal ranges as moist low-level westerly flow increases ahead of the front. Much of the surface front should be through the Bay Area by mid-morning, and late morning for areas further south along the Central Coast. Aided by a robust 150 kt NW-SE oriented jet on the back side of the low, this will be a rather quick-moving front with little-to-no chance of stalling. However, this jet and continued support of an enhanced northwesterly Eastern Pacific jet along the West Coast will support gusty northwest winds to 25-35 mph along coastal areas and NW-SE oriented valleys through the weekend. Rainfall amounts Saturday will be in the ball park of 0.4-0.75" for most locations, with a few seeing upwards of 1-1.25" in the coastal ranges of the North Bay and the Santa Cruz Mtns. Behind the cold front Saturday afternoon and evening, there is a slight chance for isolated thunderstorms across the area. Scattered showers will persist into Saturday evening, but conditions appear favorable for a few locally strong updrafts that would support a rumble of thunder or two, as well as small hail. Deep convection would not be supported, given limited cooling aloft, promoting a more stable environment aloft. Thus, any storms that do develop would be relatively short-lived. Really nothing out of the ordinary for us during these typical cold core systems, just more resemblant of a system we'd see in January rather than May. && .LONG TERM... (Sunday through next Thursday) Issued at 1237 PM PDT Fri May 3 2024 Sunday looks to be on the drier side with the low departing. Temperatures the next few days will be on the cool side with afternoon high temps dropping by as much as 18 degrees for inland locations. Low temps Sunday morning will be in the 40s for most, with a few pockets of upper 30s for inland and high elevation areas. Otherwise, a warm up is on tap for the rest of next week as the pattern becomes more ridge-dominant. By Wednesday, expect afternoon highs in the 70s to near 80, and the mid-to-upper 60s along the coast. && .AVIATION... (18Z TAFS) Issued at 1126 AM PDT Fri May 3 2024 VFR lasts until the early to mid evening for most terminals before IFR/LIFR level clouds move inland. Winds stay W/NW and remain gusty through the evening. As stratus approaches in the evening, winds become light to moderate, and slowly turn to become more S/SW ahead of the approaching low pressure system. By the mid morning hours of Saturday, most terminals will see winds increase once more to become breezy and gusty out of the SW, and rain begins, lowering visibilities at terminals. Cloud decks are expected to improve to become IFR/MVFR as the rain approaches. Rain continues into Saturday afternoon before dissipating, with winds turning to become N/NW and breezy. Vicinity of SFO...VFR conditions last through the evening, with strong wings gusting to around 35 knots expected. Stratus makes moves inland in the late evening, bringing IFR conditions as winds reduce. Winds reduce further into the night and turn southwesterly. These winds become gusty as the rain arrives early Saturday morning with MVFR CIGs and slight reductions in visibilty.Winds turn to become W/NW in the later morning, but rain lasts through the afternoon. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...IFR/LIFR CIGs push inland in the early evening. IFR/LIFR CIGs last through the majority of the overnight hours with lighter winds. As the rain band arrives, expect CIGs lift to become IFR/MVFR late Saturday morning. Gusty westerly winds build along the rain band. && .MARINE... (Tonight through next Wednesday) Issued at 425 PM PDT Fri May 3 2024 Breezy to gusty northwest winds continue with gale force gusts possible over the southernmost zones. This evening, a low pressure system and associated cold front will arrive from the north, bringing rain and moderate to fresh breezes across the waters. Winds will turn briefly southwesterly ahead of the system early Saturday morning, but turn to become northwesterly once more in the late part of Saturday morning. Rain ceases late in the day Saturday, and winds ease to become moderate into the new workweek. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay- Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Gale Warning until 3 AM PDT Saturday for Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory from 3 AM to 9 AM PDT Saturday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Behringer LONG TERM....Behringer AVIATION...Murdock MARINE...Murdock Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea ####018009241#### FXUS65 KGJT 032345 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 545 PM MDT Fri May 3 2024 .KEY MESSAGES... - A system will brush the northern tier of eastern Utah and western Colorado today, bringing a few valley rain and mountain snow showers through this evening. Minor accumulations are expected with little to no impacts. - Scattered showers and isolated thunderstorms are possible late Saturday mainly in the mountains. Elsewhere expect warmer and dry conditions. - A strong system is expected on Sunday and Monday. It will bring widespread precipitation and strong winds. A High Wind Watch has been issued for much of eastern Utah and far western Colorado Sunday morning through Sunday evening. && .SHORT TERM /THROUGH SATURDAY NIGHT/... Issued at 348 PM MDT Fri May 3 2024 The cold front and upper level jet associated with the shortwave trough moving across the north is evident both on satellite and radar across the eastern Tavaputs in northeast Utah into northwest Colorado across the Flattops and into the northern Park Range. Some light showers are occurring in Craig and Hayden with rain at Hayden and rain flipping over to snow at Craig. Roads remain wet to dry according to webcams in that neck of the woods with trace accumulations on the grassy surfaces north of Craig where it's actively snowing. All in all, impacts remain minimal with maybe 2 to 5 inches of snow at the higher elevations of the Park Range but other than that, roads are expected to remain wet. Much different story along and south of I-70 where dry conditions are evident as relative humidity is in the teens with winds gusting in the 30s and 40s. Some locally higher gusts are occurring due to presence of virga showers but these gusty winds combined with the low relative humidities is leading to critical fire weather conditions at times. Temperatures today along and south of I-70 are sitting at 4 to 8 degrees above normal with areas north of I-70 cooler at 5 to 10 degrees below normal. Showers should come to an end early this evening as this shortwave over the north exits and the jet and cold front lift northward as a warm front by Saturday. Strong WAA is expected to take place Saturday afternoon with high temperatures warming by about 5 degrees along and south of I-70 with a warm up of 10 to 15 degrees from today across the north. Highs on Saturday will be 5 to 10 degrees above normal across most of the area. In this southwest flow, we will still see some breezy conditions, but winds are expected to be less than today as the jet lifts north and shortwave ridging takes place. The hi-res CAMs are indicating a bit of instability Saturday afternoon with a weak shortwave moving through the southwest flow, skirting the divide, so isolated to scattered thunderstorms are possible along the western Colorado mountains mainly along the divide. The gradient tightens Saturday night into Sunday ahead of a strong closed low that will dive southeastward from the PacNW into the Great Basin, settling over Nevada by Sunday morning. More on this in the Long Term discussion below. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 348 PM MDT Fri May 3 2024 By Sunday morning, eastern Utah and western Colorado are expected to be sandwiched between a ridge over the Great Plains and a strong Pacific Low dropping into the Great Basin. Wrapping around the base of this low, an intense southwesterly jet is expected to push into the region on Sunday. Strong winds are expected throughout the column, with 45-60 knots at 700mb and 95-110 knots at 250 mb. 700 mb is roughly the same altitude as some of the highest peaks in eastern Utah and western Colorado, so at a baseline, without factoring in any other daytime boundary layer mixing or virga shower enhancement, mountain locations are looking at least 50-60 mph gusts on Sunday afternoon, with valley locations looking at a baseline of at least 35-45 mph. But of course, we do have to account for those other factors, with strong diabatic heating allowing for deep boundary layer mixing to tap into and bring down the much higher windspeeds aloft, and virga showers breaking out ahead of the approaching cold front. With all these other factors accounted for, another 10-20 mph added onto the baseline makes a reasonable forecast, and is bared out by probabilistic guidance indicating a high probability (>99%) of gusts 45-55 mph in the valleys and 55-65 mph for the mountain regions. Peak gusts into the 60s across the lower elevations and into the 80s at higher elevations will also be possible especially across eastern Utah and far western Colorado zones. Eastern Utah will likely see some of the highest gusts as the jet remains overhead here the longest, providing ample time for deep mixing to tap into the jet and mix down stronger gusts through the day. A High Wind Watch has been issued for all valleys and most mountain areas of eastern Utah, as well as the lower valleys and mountains of far western Colorado where potential and confidence is highest for gusts 55 to 65 mph in those valley zones and gusts to 75 mph in those mountain areas. The High Wind Watch will begin 8 AM Sunday and last through 10 PM. Stay tuned for updates relating to this situation, and if you have outdoor furniture or other objects prone to being disturbed by strong, gusty winds, take the time now to prepare. The strong winds are just the first part of the impacts from this approaching Pacific low. An potent cold front is progged to move through late Sunday into early Monday morning, with substantially colder air moving in behind it. 700mb temperatures on Sunday morning are currently forecast around 4C, and within 24 hours are forecast to drop to nearly -7C. In reflection of this, snow levels will start out on Sunday morning at 9500-10000 feet, and will crash down to 5500-6000 feet by the same time on Monday. Only the highest elevations will see snow for the duration of this system, with most everywhere else beginning with rain showers on Sunday evening. Higher elevation valleys and lower slopes of the mountains will see a changeover to snow as the cold front passes. Current guidance doesn't keep much precipitation around in the post-frontal airmass, with the exception of orographic showers across the northern mountains, so little if any accumulating snow is expected for most locations. The northern and central mountains remain most favored to see the highest QPF, with totals 0.50" to 1.00" still in the forecast from Sunday morning through Monday night. The southern mountains may see 0.25" to 0.50" total through the same period, while the lower elevations can expect 0.25" or less. Most locations will see this all or mostly in the form of rain, although the central and especially northern Colorado mountains above 9000 feet will see a substantial chunk of that QPF in the form of several inches of snow. Travel over mountain passes may be a bit messy on Monday morning. Cold and unsettled northwest flow sets up in the wake of this low, which is forecast to eject into the northern Plains Monday evening. Some wrap around moisture from this low combined with favorable flow will keep light orographic showers going over the northern mountains. General troughiness is expected to linger from Tuesday on through the end of the week, with multiple waves riding the northwesterly to westerly flow over eastern Utah and western Colorado and keeping mountain showers a possibility most afternoons. The cooler air that moves in with the cold front late Sunday into Monday will remain in place through the late week period, with temperatures running 5-10 degrees below normal. That means highs in the 50s to low 60s across the lower elevations, with 30s-40s up high, until Friday when the blended guidance indicates temperatures warming to near normal values. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 540 PM MDT Fri May 3 2024 Gusty southwesterly winds continue at this hour but will be dying down over the next few hours and by 03Z, gusts should be over. As far as ceilings and visibilities are concerned, a cold front is bringing some precip and clouds to KHDN, KASE, and KEGE though only KHDN is MVFR at the moment due to some snow. Having said that, conditions should improve for those areas as well over the next few hours. Overnight, mostly clear to clear skies expected with light winds. Tomorrow, few to scattered skies on tap with lighter winds. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...High Wind Watch from Sunday morning through Sunday evening for COZ001>003-006-011-017-020-021. UT...High Wind Watch from Sunday morning through Sunday evening for UTZ022-024-025-027>029. && $$ SHORT TERM...MDA LONG TERM...BGB AVIATION...TGJT ####018005786#### FXUS61 KBGM 032346 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 746 PM EDT Fri May 3 2024 .SYNOPSIS... High pressure will give way to a slow moving frontal boundary that will push through the area Sunday. High pressure looks to be short lived early next week before another frontal boundary and areas of low pressure move through most of next week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... 645 PM Update... There was not much to change with this update. Sky cover was lowered some, at least until the showers from the west move in. The slow moving showers are expected to move in later this evening, so PoPs were left untouched for now. Temperatures and dew points were touched up based on the latest conditions. Most locations are still in the 70s. Otherwise, conditions remain quiet for now as we monitor the showers in western NY and PA. Previous Discussion... High pressure in place across our region will attempt to slow down a cold front approaching from the Great Lakes. This should keep most of the showers with the front west and south of the region through most of Saturday. Though a few of the models have a glancing blow from some light showers in NE PA and west of the Finger Lakes in NY. Coverage of showers should ramp up Saturday night given increasing moisture and lift ahead of the frontal boundary. QPF through Saturday night looks to be a half inch or less, so no concern for flooding issues. Instability also looks to be very little if any does happen to develop. Temperatures tonight look to be a few degrees warmer due to clouds only falling to around 50 then struggle to rise into the low 60's on Saturday. Lows look to end up a few degrees cooler Saturday night. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 120 PM Update... Zonal flow pattern aloft keeps conditions relatively active during this period. Rain showers are expected to continue on Sunday as an occluded front slowly moves eastwards. Meanwhile a low pressure system over the Great Lakes drags a cold front into our region by Sunday evening. This will bring more showers with a few thunderstorms possible in the evening hours. Rainfall amounts are up to a quarter inch but any evening thunderstorms that develop could drop an inch of rain. Instability parameters are weak on model guidance, therefore not expecting much concern with these storms. Temperatures cool on Sunday with highs ranging in the low 50s to low 60s. Overnight temperatures are not expected to deviate far off of daytime highs. Lows will range in the upper 40s to mid 50s. A secondary cold front could bring some scattered rain showers Monday through Monday night. Not expecting a lot of rain with this system as the levels remain relatively dry. Precip chances are more favorable to the south of our region. Otherwise once this weak system moves thorough conditions remain dry overnight with brief high pressure building in over the Great Lakes. Temperatures on Monday will climb into the upper 60s to mid 70s in the afternoon and fall into the upper 40s to low 50s overnight. && .LONG TERM /TUESDAY THROUGH FRIDAY/... 120 PM Update... A warm front draped over the midwest approaches the region on Tuesday. Model guidance shows some timing differences in the arrival of this system. Regardless showers are expected to move in at least by the evening time frame and last overnight. This should leave most of Tuesday precipitation free. As of now Tuesday appears to be the driest day during this period. Warm front passes sometime Wednesday through Thursday bringing in more rain showers with afternoon thunderstorms. Similar pattern continues into Friday as well with yet another disturbance moving into the region. Otherwise temperatures during this period will remain mild with highs in the upper 60 to upper 70s and lows in the upper 40s to mid 50s. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/. 745 PM Update VFR conditions are expected to prevail areawide through tonight, and much of the day on Saturday. Expect just sct to bkn mid and high level clouds around during this timeframe. Later Saturday afternoon; after 18-21z Saturday CIGs do begin to lower into the MVFR and perhaps MVFR Fuel Alt category at AVP as periods of light rain begin. Overall trends are for higher CIGS and less rain further north Saturday afternoon/evening, for locations such as BGM and ELM which look to remain generally lower end VFR through the end of this taf period. ITH, SYR and RME are forecast to remain solidly VFR through early Saturday evening, with again, just a mix of mid and high level clouds. Winds are east-southeast up to around 10 kts overnight into Saturday morning. These winds turn more southeasterly and increase between 5 to 15 kts, with a few gusts to 20 kts possible late in the day. Outlook... Saturday evening through Sunday night...Periods of rain will bring restrictions to the entire forecast area. Looking mainly MVFR to MVFR fuel Alternate, but some occasional IFR restrictions are also possible, mainly on Sunday. Monday...Lingering Ceiling restrictions in the morning, then likely becoming VFR later in the day. Monday Night and Tuesday...Mainly VFR expected. Tuesday night and Wednesday...Increasing chance of rain and restrictions. Embedded thunder also possible on Wednesday. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...MWG NEAR TERM...BTL/MWG SHORT TERM...ES LONG TERM...ES AVIATION...MJM/MWG ####018003993#### FXUS63 KFGF 032346 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 646 PM CDT Fri May 3 2024 .KEY MESSAGES... - A few weak thunderstorms possible north of Highway 2 and the southern portion of Grant, Ottertail, Wadena this evening. - First chance of the season for organized thunderstorms arrives Monday/Tuesday, with isolated stronger storms possible. && .UPDATE... Issued at 646 PM CDT Fri May 3 2024 Spotty showers continue to progress eastward in the north, with the showers brought on by Frontogenesis in the south starting to push SE out of the area. Last check, we had received 0.07" at the office at 4:45PM. So even though these showers sound loud, not much actual QPF with them. Forecast remains on track. UPDATE Issued at 428 PM CDT Fri May 3 2024 Added some chance POPs through 00z to account for these diurnal showers north of HWY 200 this afternoon. Given that these are fueled by the sun warming the ground, they will quickly fall apart after sunset. Forecast remains on track otherwise. && .DISCUSSION... Issued at 350 PM CDT Fri May 3 2024 A quick shortwave will move across the international border to give our northern counties the chance for some brief showers but amounts look to be around 0.20 inches or less. This evening a band of 850mb fgen will bring shower chances across the far southern valley into west central Minnesota rain; amounts look to be under 0.50 inches. If any thunderstorm do develop as models hint at the availability of some instability the greatest threat looks to be lighting and some pea size hail at the most tonight. Sunday, A temporary ridge sets up to give us a break in this wet pattern with clear to partly cloudy skies and temperatures in the 60's with some areas reaching 70. However, Monday, a negatively tilted trough will increase the chances for showers and gusty winds starting in the afternoon. A strong pressure gradient ahead of the low will see south/southeast surface winds climb over 20 mph with an 80% chance for H850 winds to be over 40 kts increasing confidence in gusty winds at the surface. This strong low level flow will also usher in strong moisture return from stemming from the Gulf of Mexico ahead of the low. Monday evening through Tuesday morning looks to be our first chance of severe thunderstorms for our area. The NBM highlights the I-94 corridor and south with 80-90% probs for CWASP values of 50 or greater, but only 10% of values greater than 65%. Looking at the 25/75 percentiles QPF values float between 0.10 and 1 inch for the CWA. With the chance for severe thunderstorms QPF values may reach 1 to 2 inches underneath the thunderstorms. Beyond Wednesday confidence decreases and clusters show a spilt between 1) northerly flow on the backside of the exiting upper low to the east and weak ridging to the west and 2) southwest flow. CPC outlooks for this time period depict us as being favored to stay below average for temps while maintaining the wet streak with more chances for rain to end the week. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 646 PM CDT Fri May 3 2024 Ceilings will lower slowly to IFR at northern TAF sites (DVL, TVF, GFK), with other sites staying in higher flight categories (FAR doesn't look to be affected by the ceiling drops at all the other sites). Winds will shift to the NW over the day Saturday, with main concerns for TAF sites being the aforementioned ceilings and associated SHRA. Some TAF sites may early drop into LIFR briefly in the morning, but they will bounce back up into IFR. Confidence was lower on the extent of this, so kept it out of the TAFs for now. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...AH DISCUSSION...MM AVIATION...AH ####018004214#### FXUS63 KARX 032346 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 646 PM CDT Fri May 3 2024 .KEY MESSAGES... - Showers and scattered storms are expected mainly Saturday. Rainfall amounts of up to a half of an inch from the showers or storms. - Active pattern develops next week with periodic showers and storms through much of next week. Timing of convection into region remains an issue and will have impacts on the severe potential across the forecast area. && .DISCUSSION... Issued at 226 PM CDT Fri May 3 2024 Today through Saturday: While quiet weather is in store for the rest of the day, guidance continues to support a shortwave moving through the area on Saturday. Accompanying this wave will be a 30 to 40kt 850mb jet that will help to increase the moisture transport. PWATs will increase into the 1 to 1.3 inch range. Recent guidance continues to show some instability moving further north, as shown by general consensus of 250 to 500J/kg of SBCAPE. The highest instability continues to be in southern Wisconsin. Despite this instability, it is not enough to promote any severe weather, even with the high amounts of shear, 30 to 50kts of 0-6km bulk shear. This means that thunderstorms will be possible as the band of precipitation moves through the morning and early afternoon on Saturday. Sunday into Monday Shortwave ridge builds into the Upper Great Lakes Region Sunday into Monday. Subsidence underneath ridge will allow for mainly dry weather across the forecast area both days. With light winds near the surface...clear skies and an inversion developing over the forecast area Saturday night/Sunday morning. There is the possibility of fog formation across parts of the area...mainly in low lying areas/river valleys. However...if northwest winds stay up enough...fog may not form. At this time...have left mention of fog out of the forecast. Warmer airmass advects into the region Sunday into Monday...as 925mb temperatures warm from around plus 10 degrees celsius Sunday to near plus 14 degrees celsius by 00z Tuesday. High temperatures will be mainly in the 60s Sunday and warming into the upper 60s to middle 70s Monday. Monday night through Friday Main forecast concerns from Monday night through Friday continues to be shower/storm chances through much of the forecast period. Upper level closed low slowly moves over the Northern Plains States and weakens during the forecast period. Latest ensembles/deterministic models continue to show differences in timing of the upper level closed low/impulses rotating around the closed upper level low into the Upper Mississippi River Valley. Confidence in timing of convection and any severe potential with the storms remains low. The latest GFS/ECMWF continue to indicate vertical motion/moisture convergence with the closed upper level low/impulses. This will produce periodic showers/storms through much of the forecast period...Monday night into Friday. Temperatures will remain near or slightly above normal with highs generally in the lower 60s to middle 70s through the forecast period. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 646 PM CDT Fri May 3 2024 VFR conditions are expected overnight ahead of a band of showers/embedded thunder that should approach KRST by sunrise and KLSE by 12-15Z Saturday. With thunder chances only around 15-25%, did not include in the TAFs at this time. Trended a bit more optimistic with ceilings, although a period of MVFR is still favored, with the higher probabilities west towards KRST (60-90%), decreasing to 50-70% at KLSE. Some potential for IFR ceilings exists for a time as low levels saturate with the showers, especially at KRST (20-40% chance), but have held with MVFR for this update. Southerly winds up to 10 kts will shift northwesterly by Saturday afternoon. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...DTJ AVIATION...JM ####018005820#### FXUS64 KEWX 032347 AAA AFDEWX Area Forecast Discussion...UPDATED National Weather Service Austin/San Antonio TX 647 PM CDT Fri May 3 2024 ...New MESOSCALE UPDATE, AVIATION... .MESOSCALE UPDATE FOR SEVERE STORMS... Issued at 647 PM CDT Fri May 3 2024 Left mover from an earlier cell split over Mexico missed Val Verde County and has moved into Crockett County. The right mover and complex of other storms in Mexico will continue southeast. WoFS and HRRR have caught onto this, and there is a potential these storms could clip Maverick County around 8-9PM. Otherwise, we will watch closely the complex of severe storms to the south of San Angelo as they move south. WoFS indicate they could make it into northeast Edwards and northwest Kerr County around 9PM. && .MESOSCALE UPDATE FOR SEVERE STORMS... Issued at 410 PM CDT Fri May 3 2024 Severe Thunderstorm Watch #179 was recently issued and includes Val Verde, Edwards, Real, Kinney, and Maverick Counties. Storms have developed in the higher terrain of Mexico and north along the dryline through West Texas. Several WoFS members indicated the potential for isolated, splitting storms across Mexico to enter portions of the Rio Grande between 22Z-02Z (5PM-9PM). Large to very large hail and damaging wind gusts will be the main threats with any storms that do manage to make it into the watch area. && .SHORT TERM... (Tonight through Saturday night) Issued at 215 PM CDT Fri May 3 2024 Convection has begun northeast of Midland along the dryline and over the mountains east of the Big Bend. This region will be active this evening and some of these storms could move toward the east into our CWA. There is a Tornado Watch in effect north of our CWA. We have chances for showers and thunderstorms this evening, mainly across the northern counties. There is a chance that some storms could be strong to severe with very large hail the primary threat and damaging wind gusts and tornadoes also possible. Convection should dissipate after midnight. Saturday will be mainly dry. Winds will shift toward the east early and then back southeast during the afternoon. This should result in less cloud cover leading to warmer temperatures over most of the CWA. A cold front will drop through north TX during the day. Convection will initiate along this front and move southward toward our area. Chances for showers and thunderstorms will increase through the afternoon becoming likely in the evening. SPC has our CWA north and west of the Coastal Plains in the Marginal Risk area for this time. All severe threats are possible. At this time the best timing for storms is late evening to early overnight. && .LONG TERM... (Sunday through Friday) Issued at 215 PM CDT Fri May 3 2024 Rain chances may be ongoing over South Central Texas Sunday morning and continue through the afternoon hours associated with a departing shortwave trough. Models hint that a complex of thunderstorms will move through part of the area Saturday night into Sunday morning, with some lingering unorganized showers and thunderstorms remaining into the afternoon. With increasing destabilization through the day, there could be an isolated threat for a severe storm or two over the area Sunday afternoon but confidence is too low for any specifics at this point. PoPs should taper off Sunday evening with drier conditions returning to the forecast the rest of the week. That said, moisture in the low to mid levels lingers on Monday and a few showers would not be out of the question over the Hill Country or portions of the I-35 corridor. Zonal flow returns over the area on Tuesday, with upper flow becoming southwesterly mid to late week as troughing develops over the northern Plains. At the surface, South Central Texas will heat up Tuesday trough Thursday with the hottest temperatures expected along the Rio Grande. In the west, triple digit heat seems likely while the rest of the area stays in the upper 80s and 90s. Elevated humidity continues east of the dryline mid to late week which could push some locations over the I-35 corridor and Coastal Plains into triple digit heat indices. A slight cool down along and low end precipitation chances return Friday. && .AVIATION... (00Z TAFS) Issued at 647 PM CDT Fri May 3 2024 Widespread IFR to LIFR ceilings are forecast to re-develop tonight across the Hill Country and I-35 corridor, along with drizzle and fog in some areas. Ongoing TSRAs to the north and west of the region are forecast to weaken late this evening and should not impact the I-35 corridor terminals. Earlier TSRA split missed DRT, and have thus removed mention of TSRA from their TAF. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 71 85 69 82 / 20 20 70 60 Austin Bergstrom Intl Airport 69 85 68 82 / 20 10 60 60 New Braunfels Muni Airport 71 88 71 84 / 20 10 60 50 Burnet Muni Airport 69 82 67 80 / 30 30 70 60 Del Rio Intl Airport 74 91 72 87 / 40 30 70 50 Georgetown Muni Airport 69 83 67 80 / 30 30 70 60 Hondo Muni Airport 70 88 69 83 / 30 20 70 60 San Marcos Muni Airport 70 86 69 83 / 20 10 60 60 La Grange - Fayette Regional 72 85 72 82 / 20 10 40 50 San Antonio Intl Airport 71 86 71 83 / 30 10 60 50 Stinson Muni Airport 72 89 72 85 / 20 10 60 60 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...76 Short-Term...05 Long-Term...27 Aviation...76 ####018003804#### FXUS63 KDVN 032348 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 648 PM CDT Fri May 3 2024 .KEY MESSAGES... - Upper level pattern remains active, with periodic chances for showers and storms through next week. - The Storm Prediction Center has a Marginal Risk (level 1 of 5) for severe storms on Saturday for portions of the area. && .SHORT TERM /THROUGH SATURDAY/... Issued at 145 PM CDT Fri May 3 2024 This Evening and Tonight: High pressure will remain in control leading to light winds and mainly clear skies with lows in the 40s to low/mid 50s far southwest. Saturday: A cold front is forecast to track across eastern Iowa and northwest Illinois during the morning and afternoon. A stronger line of showers and storms moving through western into central Iowa tonight (Friday night) is expected to gradually weaken into Saturday morning as it pushes into a more stable air mass across our western outlook area (with surface dewpoints only in the 40s early in the day). However, some rain is likely as this first wave moves through and have 50-70% chances west of the Mississippi River for the morning hours. Low-level theta-e advection coupled with diurnal heating will allow for the build up of SBCAPE into Saturday afternoon for locations along and east of the Mississippi River. This will coincide with the passage of the cold front and could result in redevelopment of scattered showers and storms between 2 PM to 7 PM, right now favored for eastern counties. Per HREF surface- based CAPE near 1000 J/kg and deep layer shear around 30 kts, the environment may be supportive of a few strong to severe storms which is in line with SPC's Marginal Risk (level 1 of 5). The primary threats are hail and gusty winds. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Issued at 145 PM CDT Fri May 3 2024 Another chilly night is expected Saturday night, with lows in the 40s to lower 50s, but Sunday, much like today, appears to be seasonally pleasant in the lower 70s. Global models are in good agreement that a large upper trof will build into the Midwest in the Monday through Wednesday time frame. This should sweep another dynamically supported warm advection band of showers and storms through our area centered on Monday night into Tuesday. The quick flow aloft, and progressive boundary should keep QPF totals from being problematic, with most spots well under 1 inch in the NBM/WPC mean. There is potential for storms to redevelop Tuesday afternoon, but confidence is low on this scenario. SPC has outlooked the area for a slight severe risk, but again confidence regarding the details is low as it will depend on timing and placement of a cold front moving through the Midwest. Stay tuned. Seasonally pleasant temperatures are forecast through Wednesday, with a bit of a cool down by late week, as the upper trof deepens over the Midwest. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 648 PM CDT Fri May 3 2024 VFR conditions under SKC are expected at least over the next 12 hours before a cold front sweeps through the area after sunrise Saturday. This front will bring increasing chances of showers and a few thunderstorms in a couple of rounds. MVFR conditions are expected with this activity, with a low chance for some strong storms at MLI and BRL. Expect southeasterly winds tonight to gradually turn northwesterly by Saturday afternoon in the wake of the front. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...None. MO...None. && $$ SHORT TERM...Uttech LONG TERM...Ervin AVIATION...Schultz ####018004729#### FXUS64 KOUN 032348 AFDOUN Area Forecast Discussion National Weather Service Norman OK 648 PM CDT Fri May 3 2024 ...New AVIATION... .SHORT TERM... (This evening through Sunday) Issued at 258 PM CDT Fri May 3 2024 Scattered strong to severe thunderstorms are expected to develop across the Texas South Plains later this afternoon. The remnants of this activity--especially any left splits--may affect western north Texas this evening before dissipating. However, with the trend of initiation farther to the southwest, it appears the chance of severe weather will be spatiotemporally limited. Large hail and damaging wind gusts will be the primary hazard. Additional thunderstorms are expected to develop across Kansas and consolidate into a complex with the remnants moving into northern Oklahoma late tonight into Saturday morning. These thunderstorms will have a threat for damaging wind gusts and heavy rainfall, which should weaken with southward extent. By Saturday afternoon, additional thunderstorms may develop during the afternoon hours along the boundary from the morning thunderstorms across Oklahoma. In addition, a complex of thunderstorms will likely develop across the Texas panhandle and western north Texas that will move eastward across at least the southern half of the area during the overnight hours. Large hail, damaging wind gusts, and flooding will be the potential hazards with the primary hazard becoming flooding. Given the recent heavy rainfall, we issued a Flood Watch from 7 PM tonight through 1 PM Sunday for all locations except northwest into west central Oklahoma (where rainfall amounts have been lighter the last week). Additional heavy rainfall will result in a risk of flooding through Sunday morning. Mahale && .LONG TERM... (Sunday through next Thursday) Issued at 258 PM CDT Fri May 3 2024 Monday: There is the potential for a significant severe weather event Monday afternoon and evening. A negatively tilted trough will eject into the Plains on Monday with a moist, highly sheared, and unstable air mass ahead of a dryline. The synoptic-scale pattern is a classic severe weather outbreak across the Plains with a threat for large hail, damaging wind gusts, and tornadoes. While there is some variation on the mesoscale details among deterministic models and ensemble members (e.g., character of the mid/upper level trough, location of the dryline, and the magnitude of capping) that will affect the location and magnitude the severe weather risk, it is important to stay weather aware on Monday as the worst case scenario (i.e., How bad could it be?) for the event is quite high with the potential for significant supercells. Tuesday: As the mid-level trough lifts to the northeast, the trailing dryline may stall across east central into southeast Oklahoma. While the dryline will be somewhat diffuse, there is a low chance thunderstorms may develop during the afternoon with a modest mid-level flow persisting across the Southern Plains. Wednesday: Additional severe thunderstorms will be possible Wednesday afternoon, especially across southeast Oklahoma with the dryline still in place. Thursday: There may finally be a lull in the risk for severe weather with a cold front moving through the area with a drier air mass advecting southward into the area. Mahale && .AVIATION... (00Z TAFS) Issued at 645 PM CDT Fri May 3 2024 VFR conditions expected until FROPA tonight and early tomorrow, with MVFR dominant thereafter. TSRA possible over/near KSPS this evening and then spreading into northern Oklahoma after 06Z. Will include PROB30 into central Oklahoma tomorrow morning as weak cold front moves from northwest to southeast over the region and ushers in northerly winds. TSRA chances will increase northern Texas and southeast half of Oklahoma toward end and beyond this forecast cycle. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 63 76 60 72 / 30 70 80 80 Hobart OK 59 74 57 74 / 40 70 90 60 Wichita Falls TX 63 79 62 76 / 30 50 90 60 Gage OK 52 69 51 75 / 80 50 60 40 Ponca City OK 61 73 56 71 / 60 70 60 70 Durant OK 64 79 64 77 / 20 40 70 80 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...Flood Watch through Sunday afternoon for OKZ006>008-011>013- 018>020-023>048-050>052. TX...Flood Watch through Sunday afternoon for TXZ083>090. && $$ SHORT TERM...10 LONG TERM....10 AVIATION...11 ####018008470#### FXUS61 KBTV 032348 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 748 PM EDT Fri May 3 2024 .SYNOPSIS... Dry and seasonably warm weather will continue across the region to start the weekend, with the exception of a few possible showers across northern New York on Saturday before widespread precipitation returns for Sunday. A period of warmer and sunnier conditions are expected for the start of the week, with more unsettled weather returning by the middle of next week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... As of 700 PM EDT Friday...A beautiful early May day acrs the North Country with temps in the mid 60s to lower 70s with mostly sunny skies. Upper air analysis and water vapor indicate mid/upper lvl ridge axis overhead, but weak short wave energy and mid lvl moisture is approaching the SLV. This has produced a broken area of light showers acrs western NY into the Ottawa Valley, with just light precip reaching the sfc. These light showers wl continue to slowly move toward northern NY tonight, with increasing chcs for light precip. Have continued with chc pops with a few hundredths of an inch of precip possible, not anticipating precip to reach CPV, as ridge holds firm. Otherwise, temps cool back into the mid 40s to lower 50s with mostly light trrn driven winds, except northeast acrs the SLV and se at Rutland. No significant changes made to crnt fcst. Previous discussion below: Surface high pressure and upper level ridging across the region haver made for a pleasant Friday afternoon, with dry conditions and seasonably warm temperatures. As we head into the evening, the upper level ridge axis will continue to shift eastward,although dry conditions will persist. There will be increasing high clouds across the region overnight associated with a frontal boundary to our west. Unlike the last few nights, increased clouds and winds will inhibit any fog development across the region. A light rain shower or two may be possible across northern New York early Saturday morning as the frontal boundary moves closer, but any measurable precipitation would be minimal. Overnight low temperatures will be mild, in the 40s to low 50s. Saturday will be another pleasant day as we remain under the influence of high pressure, with mostly dry weather. Temperatures will warm into the 60s to near 70 in some of the broad valley locations, with high clouds remaining overhead. Dry weather will continue through most of Saturday night, with the latest guidance continuing to trend on the drier side for Saturday night with a strong ridge axis in place. Another mild night is expected, with temperatures in the 40s to low 50s ahead of approaching widespread precipitation on Sunday. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 303 PM EDT Friday...PWATs rise to around 1.5 standard deviations above normal on Sunday as moisture with Gulf of Mexico origin looks to overspread the region. Upper level pattern shows a stout omega block shifting east of our area into Maine, increasing shower chances and coverage on Sunday. However, organized convection is not expected as the main jet energy associated with the shortwave trough moving eastward from the Great Lakes is diverted into Quebec. As a result, the main trough axis does not approach North Country until sometime next Tuesday. This will be discussed in the long term section of the forecast discussion. Indeed, forecast soundings show a lack of surface-based instability, so showers with brief locally heavy downpours look to be the main risk. While there could be embedded thunder due to elevated instability, no organized thunderstorms are anticipated. PoPs do increase to the likely category with scattered to perhaps numerous showers on Sunday. While there would likely be widespread wetting rainfall, QPF amounts are quite manageable in the 0.1 to 0.3 inch range with locally higher amounts. Indeed, the MMEFS shows none of our area rivers going into action stage. Sunday will be quite a bit cooler than Saturday, with highs only in the 50s with low 60s possible if there are breaks in the rain or clouds. In addition, a 40-50 kt 925mb southerly low level jet overspreads the region on Sunday. NAEFS situational awareness ensemble table shows the v vector wind rising to almost 2.5 standard deviations above normal, so it will be breezy if not blustery. A mitigating factor is that the waters of Lake Champlain is still quite cold with water temperatures still in the low to mid 40s, which is almost isothermal to the forecast 925mb temperatures in the +5 to +8C range. That could reduce the mixing potential in the boundary layer. So have mostly kept wind gusts in the 30 to 35 mph range across the Champlain Valley despite the southerly wind component being anomalously strong. Overall, no overall hazardous weather to speak of but Sunday does look to be a less than ideal day for outdoor activities. Heading into Sunday night, showers taper off and the boundary layer looks well mixed enough to preclude widespread fog development. Temperatures stay quite mild in the mid 40s to low 50s. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 303 PM EDT Friday...The overall weather pattern heading into the first full week of May can be described as unsettled with no real significant warm up or impactful weather. Unsurprisingly, the CPC 8-14 day temperature outlook favors near normal temperatures and leans towards above normal rainfall. For reference, typical highs for North Country in early May are in the low to mid 60s, while average overnight lows are in the mid 30s to low 40s. The upper level pattern features a positively tilted omega block sandwiched between an anomalously deep trough across the Rockies/northern Great Plains and another trough over eastern Quebec/Newfoundland. H5 height anomalies favor a period of widespread showers and thunderstorms in the Tuesday/Wednesday time frame, as positive H5 height anomalies give way to near normal values. Depending on the timing of the associated surface cold front, ingredients may exist for a few stronger storms. Taking a first look at ensemble guidance probabilities, it does look like the better chance for organized convection is across our southwestern zones, with more garden variety thunderstorms towards Vermont and the Champlain Valley. This makes sense from a synoptic perspective as the aforementioned positively tilted omega block may not be that easy to dislodge. As a result, our region only gets a piece of weak shortwave energy that peels off from the base of the northern Great Plains upper low and deamplifies as it tracks towards southern Ontario/Quebec. In simple terms, our region gets a glancing blow in terms of dynamical forcing and as a result, the odds for any stronger convective storms greatly diminish. While we are still 4 days away, model trends are favoring an unsettled but benign pattern for North Country in the upcoming week. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Through 00Z Sunday...VFR conditions will prevail through the forecast period, with the possible exception of brief MVFR conditions if scattered showers are sufficiently heavy at MSS and SLK. The timeframe for precipitation is mainly in the 05Z to 11Z period for MSS and 07Z to 12Z period for SLK, with showers expected to peter out as they move farther east. Terrain driven flow at the start of the period, mainly 3 to 7 knots, will trend southerly after 06Z, and then southeasterly after 18Z. Ceilings will tend to lower with time but remain at VFR levels through the period. Outlook... Saturday Night: VFR. Chance SHRA. Sunday: Mainly MVFR, with areas VFR possible. Definite SHRA. Sunday Night: Mainly MVFR, with areas IFR possible. Chance SHRA. Monday: Mainly VFR, with local IFR possible. Slight chance SHRA. Monday Night: VFR. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. Slight chance SHRA. Wednesday: VFR. Likely SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Kremer NEAR TERM...Kremer/Taber SHORT TERM...Chai LONG TERM...Chai AVIATION...Kremer/Kutikoff ####018006169#### FXUS63 KDMX 032348 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 648 PM CDT Fri May 3 2024 ...Updated for the 00z Aviation Discussion... .KEY MESSAGES... - Storms and showers arriving after midnight tonight near and east of Highway 71 - severe risk is small hail, gusty winds possible - Stormy weather returns later Monday into Monday night with severe weather possible, perhaps redeveloping later Tuesday - More clouds than sunshine, fleeting showers, and trending towards seasonal levels mid to late next week && .DISCUSSION... Issued at 232 PM CDT Fri May 3 2024 Morning fog was rather impressive from visible satellite this morning highlighting the numerous river valleys across portions of Iowa. This fog was able to fully dissipate between 9 and 10am. Now, upper level water vapor imagery shows a parent upper low that is spinning into the Manitoba province. Dropping through the Intermountain West into the northern/central Rockies around this parent upper low is the shortwave trough that will bring thunderstorms into Iowa late this evening and our forecast area after midnight. An area of instability up to around 500 J/kg of MUCAPE is expected ahead of a cold front along with steep mid-level lapse rates and sufficient shear for storm organization. Forecast soundings show storms will be elevated in nature and thus pose a risk of primarily small to around 1" hail with isolated gusty winds possible. Convective allowing models show a few healthy updraft helicity tracks entering western Iowa, but their strength quickly wanes as they move toward central Iowa. Further, even the more aggressive WRF-ARW and FV3 are showing wind gust potential topping out between 30 to 40 knots. Overall, the marginal risks by the Storm Prediction Center on day 1 into day 2 seems to handle this risk well. Rainfall amounts look to be highest over western into portions of central Iowa, mainly east of I-35 with 12z HREF localized probability matched mean values of half an inch with small areas of 1.25 to 2 inches possible. The water issues over our southeastern forecast area - namely Monroe and parts of Appanoose and Wayne counties including the Cedar Creek basin - may then be spared from a return of water problems. These storms will be over eastern Iowa around midday leaving behind breezy winds from the north-northwest, decreasing clouds, and highs in the 60s in most central Iowa cities. With a clear sky over much of central Iowa, decreasing winds, and the rainfall from Saturday morning, we are looking to be set up for another round of dense fog. However, drier air will be pulled into Iowa and brings into question whether this will negate the other favorable factors. After any fog dissipates Sunday morning, weak ridging will pass overhead and a southern stream wave continues to trend south of the state with the latest NBM PoPs staying south of Iowa. At the same time, a potent shortwave trough over the western CONUS will move eastward toward the region and take on a negative tilt as it lifts northeastward into our region Monday into Monday night. Low level kinematics will be favorable at 40 to 50 knot Monday night in the region with resulting deep layer shear looking healthy for organized convection. This wind field will draw moister air into the region with low 60 surface dewpoints making their way to near if not into at least southern Iowa later Monday. MUCAPE values will be over 1000 J/kg and mid-level lapse rates rates will be steep around sunset Monday, but both are forecast to diminish into the evening to some degree. Forecast sounding continue to show an elevated warm layer that may keep storms elevated; however, given the strong kinematic fields in the 0-3km layer, cannot rule out a tornado risk with any line of storms if the orientation can become favorable to the low level shear vector. So, at a minimum, at least strong storms look favored, especially over the western half of the state Monday night, with severe weather possible. Like yesterday, SPC maintains probabilities largely southwest of our area on Monday and southeast of our area on Tuesday. Latest Colorado State's machine learning random forest outlook and CIPS Experimental Analog- Based Severe Probability Guidance continues to paint 5 to 15% probabilities of severe over more of central Iowa each day lending credence to the idea of some strong to if not severe storms in portions of our forecast area. The strong to severe storm risk may persist Tuesday afternoon given the SPC, CIPS, and CSU mentioned above, but if things speed up then this may all be pushed off to the east on Tuesday. Wednesday through Friday has broad brushed PoPs in our current forecast as the shortwave trough that will bring our storms chances the first two days of next week will lift up and meander over the Montana and western Dakotas area. This will keep weak shortwaves passing over the state and thus keep varying degrees of clouds, fleeting showers, and temperatures trending closer to normal in the 60s by late next week. Severe weather Wednesday through Friday looks unlikely as the instability will be away from the state. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 644 PM CDT Fri May 3 2024 VFR skies to become BKN to OVC for northern sites in the next 6 hours ahead of showers and thunderstorms that will move in after 06. Highest confidence in thunder at KFSD and KDSM, timing from previous issuance appeared on track. Have added VCTS to KOTM for the morning hours. Lower confidence at KMCW and KALO so have left out of TAF for now, but will continue to evaluate. IFR cigs anticipated with storms, gradually becoming VFR and dry through the morning. Gusty northwest winds to fill in behind after 18z. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Ansorge AVIATION...Jimenez ####018007736#### FXUS63 KLSX 032349 AFDLSX Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 649 PM CDT Fri May 3 2024 .KEY MESSAGES... - Isolated strong to severe thunderstorms are possible from 2pm to 7pm Saturday. Hazards include up to 60 mph winds and up to quarter sized hail. - Confidence is increasing in a multi-day severe event taking place in the central U.S early to mid-next week. However, there is still uncertainty regarding details like timing, exact location, and how one day's thunderstorms will impact the next day's severe potential. && .SHORT TERM... (Through Late Saturday Night) Issued at 249 PM CDT Fri May 3 2024 Thursday night/Friday's cold front will continue to slowly buckle northward through the bi-state tonight as a quasi-stationary boundary. Meanwhile, a mid-level shortwave and surface cold front will push east through the Plains, arriving in Mid-Missouri early Saturday afternoon. This system will push the boundary to the northeast and leave us within its warm sector. Because of this, temperatures Saturday will be much warmer than they were today, reaching the mid-70s to mid-80s. Moisture will also pool into the area, mostly along and just ahead of the incoming cold front. Instability will be maximized here with SBCAPE values of 1500-2000 J/kg. Deep layer shear will be lacking, though, ranging from 20-30 kts. Modest CAPE and bulk shear values are expected to result in a severe weather threat much like yesterday - disorganized clusters of outflow dominant cells. Although we're confident in thunderstorm development, strong to severe thunderstorms are expected to be isolated in nature due to them being outflow dominant and likely quick to intensify and even quicker to die. The greatest potential for severe weather will be between 2pm and 7pm as the front is passing through the CWA. In any thunderstorms that become severe, damaging winds of up to 60 mph and up to quarter sized hail are possible. We're confident in the end time of the severe potential, as the front will be close to exiting to the southeast, and that coincides with the downfall of daytime instability. With the lack of appreciable shear, diminishment in instability will be detrimental to the life of any thunderstorm. Saturday night will be relatively chilly for portions of the areas surface high pressure passes to our north. Areas in northeast Missouri and west-central Illinois are forecast to fall into the upper 40s. To the south, further from the influence of the high and under more dense cloud cover, low temperatures may not fall under 60 degrees. Jaja && .LONG TERM... (Sunday through Next Friday) Issued at 249 PM CDT Fri May 3 2024 Sunday will be a relatively quiet opening to the week, almost literally the calm before the storm as we face a potential multi-day severe event between Monday and Wednesday. Despite the relative quiet, wet weather is expected beginning Sunday afternoon and continuing into overnight. This is due to a shortwave passing through the Mid-Mississippi Valley from the southwest and driving a weak surface low through our CWA. This surface low will cause Saturday's remnant cold/stationary front to buckle back north as a warm front with showers with embedded thunderstorms along it and within the system's warm sector. Severe weather is not expected, even earlier in the afternoon, due to weak lift, weak moisture convergence along the front, mid-level subsidence, and minimal instability (<250 J/kg MUCAPE). High temperatures Sunday will be near normal, landing in the 70s areawide. Monday kicks off the potential for multiple days of severe weather extending from the central and southern Plains into the southwestern Great Lakes and western Ohio Valley. A deep mid-level closed low will be responsible for this as it ejects northeast into the Plains on Monday. At the surface, two low pressure systems will develop lee of the Rockies, advecting warm air and moisture into the region ahead of a dryline and developing cold front. The dryline will act as a trigger for convective initiation in the Plains on Monday. On Tuesday, the system as a whole will be further east, and a shortwave and vorticity lobe will swing through our region. The cold front will be further east as well, shifting the severe threat into our area. Guidance across the board is in consensus that instability, deep layer shear, moisture, and synoptic level dynamics will all be favorable for severe weather on Tuesday and again on Wednesday as the cold front continues its eastward advancement. With the environment that may be in place, no hazard can be discounted at this point. Of course, this multi-day event begins four days out from now, so there's uncertainty to discuss. Firstly, although WPC cluster analysis shows consistency amidst guidance in the mid-level trough/closed low early next week (positioning, strength, size), there are differences in the phasing that impact the mid-level flow and thus impact the timing of the overall system. For a multi-day system like this, a faster or slower passage of the system could increase or decrease our potential for severe and/or lengthen or shorten our window for it. A faster frontal passage may shift Wednesday's severe threat further east and out of our CWA, whereas a slower frontal passage may extend our severe threat into Thursday. There's also the question of how/if severe weather to our west impacts our severe weather threat for the following day (Monday into Tuesday and Tuesday into Wednesday). Overnight low-level jets may cause ongoing convection to continue into the next morning, potentially dampening the potential for severe that day. The opposite scenario is also equally as likely - thunderstorms dying in the evening could lay down outflow boundaries and open up the potential for rapid destabilization the next day, increasing our chances for severe. All of this to say despite the very favorable synoptic set-up for severe, there's still plenty of variability that could sway our severe potential and its timing. Jaja && .AVIATION... (For the 00z TAFs through 00z Saturday Evening) Issued at 638 PM CDT Fri May 3 2024 Light and variable winds will accompany VFR ceilings through tonight. There is the potential for patchy fog very late tonight into early Saturday morning. The best support for this will be over southeast Missouri and far southwest Illinois. It cannot be entirely ruled out at KJEF/KSUS/KCPS, but signals are not strong and was therefore left out of the TAF for the time being. Winds veer out of the south and southwest Saturday morning into Saturday afternoon ahead of a cold front that will bring increasing chances for showers and thunderstorms during the afternoon. Initially, a few thunderstorms could impact KCOU/KJEF in the mid to late morning, but better potential will be in the afternoon. Diurnal heating provides greater instability for redevelopment, which then pushes eastward into the remaining terminals to include KUIN and metro terminals. Direct impact from thunderstorms could result in heavy rain, gusty winds and brief reductions to visibility. Much of the activity will weaken and move east around or just after 00z Saturday evening. Maples && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX