####018006096#### FXUS61 KBTV 031125 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 725 AM EDT Fri May 3 2024 .SYNOPSIS... Dry weather persists through Saturday, except over northern New York where a few light rain showers are possible on Saturday. Temperatures will be mild, with highs in the 60s and low 70s. Widespread rainfall returns for the day on Sunday before dry conditions return to start next week. Conditions mid week through Friday are trending wetter with daily chances of rain. && .NEAR TERM /THROUGH SATURDAY/... As of 638 AM EDT Friday...Low clouds and some areas of fog remain entrenched across the North Country. In most areas the fog formed where skies cleared but in some others it formed under the low stratus deck. The fog should lift pretty quickly this morning but it will take longer for the stratus deck to scour out. High clouds are already entering the region from the west and they will continue to increase as the day progresses. Previous discussion follows.. Previous Discussion...The region is currently between a shortwave trough digging south over the Atlantic and a ridge building in from the west. Low clouds are lingering from weak northeasterly flow and trapped low-level moisture, and they should persist for the rest of the night. Fog has developed in a few of the sheltered valleys where clearing has occurred, particularly where it rained yesterday. Due to the cloud cover and some light winds, temperatures should not fall much more tonight, so lows will generally be in the 40s. The ridge will build in during the day today and it will initially clear out the lingering low clouds and fog. Combined with warm advection from increasing southerly flow, temperatures will rise into the upper 60s and low 70s, with the highest temperatures expected in the St. Lawrence Valley. The sun will be short lived as high clouds ahead of an occluded front will spread into the region not long after the low clouds depart, so much of the sun will likely be filtered. The front will be able to spread a few showers into northern New York tonight, but it will be weakly forced and falling apart as it arrives, so precipitation amounts should be under a tenth of an inch. High pressure situated over Atlantic Canada will be stubborn and prevent the rain from reaching Vermont. The high remains in place for Saturday and the day should be be mostly dry, even over New York, where at most there will be a couple light showers. The high clouds should remain in place but an absence of lower clouds should allow temperatures to rise into the 60s across the region. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/... As of 417 AM EDT Friday...Ensemble and deterministic models have trended much drier Saturday night keeping the highly amplified ridge axis over the North Country. This will delay the onset of precipitation while flow aloft continues to stream ample moisture northward. As such, QPF was cut from the overnight hours with only a few hundredths possible over northern New York and nothing for Vermont. Temperatures will remain mild in the 40s to low 50s. Frontal passage is still expected through Sunday, moving quickly west to east as ridging shifts eastward. Total QPF should be less than 0.5" with general amounts ranging from 0.05-0.33". Highest amounts will be across the Greens of southern Vermont with amounts decreasing northward. Temperatures will be seasonal in the mid/upper 50s to low 60s. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... As of 417 AM EDT Friday...Post frontal thermal advection will be near neutral given the replacing airmass will originate over the central Plains. As ridge amplifies Monday/Tuesday, dry conditions will prevail with temperatures warming above seasonal averages into the upper 60s to low 70s. The next wave continues to be projected to move into the North Country Tuesday night through Wednesday night possibly bringing another round of elevated PWATs, decent instability, and some thunderstorm chances. Instability trends have decreased from previous model runs, but will continue to monitor for potential of stronger cells. For late week, guidance has trended wetter with mean longwave troughing stagnating between the Great Lakes region and the North Country. This pattern would favor active weather and possibly keeping daily rain chances through the end of the week. With fast flow aloft, any troughs moving through will be moving quickly. Temperatures are expected to remain around seasonal averages with colder air locked well north. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... Through 12Z Saturday...A low cloud deck is present over the region and every terminal has low ceilings causing either MVFR or IFR conditions. Fog and mist are also present at some of the terminals. The fog should dissipate quickly this morning but it may take a couple more hours for the low cloud deck to lift and scour out. However, all terminals should be VFR by the afternoon. VFR conditions will persist well into tonight at all terminals as wind should prevent any fog formation. Ceilings will drop again tonight which may cause SLK or MSS to lower into MVFR by Saturday morning. Winds will be relatively light during this period, varying from southerly to calm and variable. LLWS is not a concern. Outlook... Saturday: VFR. Chance SHRA. Saturday Night: VFR. Chance SHRA. Sunday: Mainly VFR, with areas MVFR possible. Likely 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. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Myskowski NEAR TERM...Myskowski SHORT TERM...Boyd LONG TERM...Boyd AVIATION...Myskowski ####018006427#### FXUS62 KCHS 031126 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 726 AM EDT Fri May 3 2024 .SYNOPSIS... Atlantic high pressure will remain across the Southeast through much of next week. && .NEAR TERM /THROUGH TONIGHT/... ***Dense Fog Advisory issued, mainly from I-95 westward through 10 am.*** This morning: Satellite imagery, surface observations, and webcams showing some fog and stratus developing across parts of the area. This is a little later than it was yesterday morning, and also there is less coverage so far. However, there is a strong inversion just off the surface, and with dew point depressions down near or at zero, the fog will expand in coverage. Since we're still not certain that there will be enough dense fog, no Dense Fog Advisory has been issued. The fog (whether it's dense or not) will dissipate by 9-10 am since the depth of the fog is somewhat shallow. Today: The mid level ridging of recent days will shift off the coast of the Southeast, while Atlantic high pressure is the main feature at the surface. The synoptic flow is southeasterly through the day, resulting in a sea breeze dominant regime. After fog dissipates, scattered to broken cumulus will prevail, while varying amounts of cirrus clouds pass through. There will certainly be sufficient insolation, and temperatures will be very similar to yesterday. We didn't go quite as warm as the 1000-850 mb thickness progs, but with a blend of the MOS and NBM, we arrive at highs in the mid and upper 80s. Coastal sections will be 5-10F cooler. A subtle level level impulse will approach from the west- southwest late in the day, and this will cause isolated to scattered convection upstream from our Georgia counties to approach. There will be some interaction of this activity with the inland moving sea breeze after 3 or 4 pm, where we show slight chance PoPs close to and west of the US-301 corridor (Allendale to Tattnall County). There is little buoyancy, plus limited MLCAPE and shear, so no strong or severe storm will occur. Tonight: A better looking short wave trough moves through the Tennessee Valley and northern Gulf coast. This along with any outflow boundaries from prior convection in and near the area, will allow for isolated or scattered showers and a few t-storms to occur. This is mainly far inland sections. There will be at least some form of fog again after midnight given the southeast and south flow in the boundary layer. However, there is likely too much mid and high level clouds from the nearby convection for dense fog to occur. We currently have mention of the "patchy" fog qualifier, and we will monitor for any dense fog potential. Low temperatures will be several degrees above climo. && .SHORT TERM /SATURDAY THROUGH MONDAY/... A mid-level ridge axis will push off the Southeast coast Saturday with passing waves of shortwave energy across the region through the short term forecast period. High pressure will remain the primary feature at the surface. Convection should be a bit more active over the weekend and into Monday with the presence of deeper moisture as PWATs increase to 1.5+ inches. Coverage of showers/thunderstorms will be highest in the daytime when instability is maximized, but with some upper forcing in play activity could linger into the overnight period. The greatest chances are focused away from the immediate coast owing to a progressive sea breeze. High temperatures will generally peak in the low to mid 80s over the weekend, warming into the mid to upper 80s Monday. Overnight lows are only expected to drop to the mid to upper 60s, with locations right along the beaches and Downtown Charleston near 70 degrees. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... Atlantic high pressure will persist through the middle of next week. Chances for showers/thunderstorms are limited Tuesday as weak forcing/remnant shortwave energy passes offshore the Mid Atlantic coast. Beyond Tuesday, rainfall chances are little to none as a ridge rebuilds overhead. This will allow max temperatures to rise into the low/mid 90s by mid next week, possibly approaching record levels by Wednesday/Thursday. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... KCHS/KJZI/KSAV: Other than a little light fog at KSAV through 13, VFR will prevail at all terminals. The potential for fog tonight t is less than recent nights, and would likely occur inland from the terminals anyway. There are no concerns for SHRA or TSRA at any the terminals with the 12Z TAFs. Extended Aviation Outlook: Scattered showers and thunderstorms are possible through Monday. && .MARINE... Today: High pressure from the Atlantic will be the main feature, and even with sea breeze influences this afternoon, SE winds will be no more than about 10 kt. Seas will be only around 2 feet. Even though it is light, the onshore flow will keep any land based fog off the Atlantic. The exceptions will be Charleston Harbor (especially the northern part of the harbor near the North Charleston Port) and the Port of Savannah, where some of the nearby fog from over the land could drift into those areas early this morning. At this time no Dense Fog Advisory is planned. Tonight: Weak high pressure continues across the maritime community. Once again the SE winds are no more than about 10 kt, with seas just 2 feet. Maybe some fog could impact Charleston Harbor and the Port of Savannah, as it tries to expand in from nearby land sections. Saturday through Wednesday: Atlantic high pressure will maintain benign conditions over the local waters. Southerly winds in the morning will back out of the southeast during the afternoon and evening hours nearly each day as the sea breeze develops. Winds will average 10-15 kt with seas 2-3 ft. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...Dense Fog Advisory until 10 AM EDT this morning for GAZ087-088- 099>101-114>116-118-137-138-140. SC...Dense Fog Advisory until 10 AM EDT this morning for SCZ040- 042>045-047. MARINE...None. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE... ####018006818#### FXUS61 KCLE 031126 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 726 AM EDT Fri May 3 2024 .SYNOPSIS... A warm front will lift north into the area this morning. Weak low pressure will move east along this front today, followed by a cold front arriving tonight. Another cold front will cross the area on Sunday. && .NEAR TERM /THROUGH SATURDAY/... Showers have filled in along the warm front in southwest Ohio and are tracking north along the I-75 corridor. Sped up the rain slightly this morning and raised temperatures at some locations. Otherwise still expecting it to be a wet day with most areas seeing precipitation at some point. Previous discussion... Low pressure is located over northern Minnesota this morning with a weaker area of low pressure over Indiana. A warm front extends from this low towards Central Ohio. Broad low pressure will make slow progress east across the area today with the warm front lifting north into northeast Ohio and Northwest Pennsylvania although not expected to make it all the way to the lakeshore. The area will be in the warm sector today but have toned down high temperatures by a couple degrees given the thickening cloud field and expanding showers. Timing of showers is somewhat difficult today given weak flow and broad moisture advection. Some showers should develop in NW Ohio as the warm front lifts north into the area this morning. Instability will be limited this morning but expect destabilization to aid in shower and thunderstorm development by mid afternoon, especially in Northeast Ohio initially and then shifting into Northwest Pennsylvania this evening. Weak flow over the area will mean storm motion will be 20 knots or less. Severe weather is not expected given modest instability and little shear. Heavy rain will be the bigger concern if any training occurs due to the relatively slow storm motion and PW values over an inch and a half. Highs today will range from near 70 towards the lakeshore to near 80 in the southeastern counties. A decrease in showers and thunderstorms is expected tonight as mid-level dry air works in from the west and instability decreases. A cold front moves southeast into the area and tends to stall, with some convergence holding on in the southeastern counties. Can not rule out a shower anywhere so will keep a pop everywhere with the highest southeast of a line from Mansfield to Erie PA. By Saturday, dewpoints will remain elevated in the low 60s. Depending on breaks in the clouds and degree of heating, ML CAPE should be a little higher with values in the 1000-1500 J/kg. Flow develops out of the south again as another low pressure system moves into the Midwest. Expect convection to initiate closer to Central Ohio and lift north through the afternoon. Most of Ohio should recover into the 70s while NW Pennsylvania will hold in the 60s. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... Progressive pattern continues into the short term forecast period and heading into the end of the weekend. Cold front to track through the CWA late Saturday night into Sunday, followed by brief high pressure Sunday night into Monday. Still looking at largely low flows/shear and saturation through the column ahead of and with the cold front, and not much of a severe weather setup but possibly storms highlighted by downpours in a high precipitation efficiency environment. General thunder outlooked from SPC, but will get a relatively short period of stabilization as the aforementioned high pressure builds in for the end of the short term. This late Sunday night/early Monday period is probably going to end up the lowest POPs in both the short and long term forecast. Temperatures cool 4-8 degrees Sunday into Monday in the wake of the cold front. && .LONG TERM /TUESDAY THROUGH THURSDAY/... The cold front that settles just south of the CWA early Monday night will track back northeastward as a warm front late Monday night into early Tuesday, and back into the warm sector. Deep upper level low over the upper midwest region will drive another cold front into the area Tuesday night in southwest flow aloft. Brief high pressure once again Wednesday before another cold front Wednesday night into Thursday. Despite the upper low that will make little headway eastward towards the northern half of the Great Lakes by the end of the long term, no real significant changes in airmass in terms of temperature expected. && .AVIATION /12Z Friday THROUGH Tuesday/... Showers with isolated thunderstorms have filled in across NW Ohio. These are originating along a warm front in SW Ohio and tracking north along the axis of better moisture. At 12Z the warm front extended from Central Indiana to Central Ohio. This warm front will lift north into the area this morning bringing a continued chance of showers. Timing of thunderstorms will be a challenge through the daytime hours as the area continues to moisten with a slow moving area of low pressure drifting east across Central Ohio. There will be a little more time for heating across north central and northeast Ohio and have included a Tempo for thunderstorms between 17-23Z in Ohio, and as late as 02Z at ERI. The airmass will be moist so heavy rain and IFR ceilings and visibilities will be possible with any thunderstorms. Outside of showers and thunderstorms, ceilings will tend to be VFR until after 02Z when a weak cold front settles south into the area. Expect ceilings and visibilities to trend towards low MVFR or IFR towards the end of the TAF cycle. Winds will generally be 10 knots or less through the period and somewhat variable. Broad low pressure will result in easterly winds ahead of the low, backing to northeasterly near the lakeshore, and eventually westerly behind the low. Outlook...Non-VFR likely with periodic showers and thunderstorms through this Tuesday. && .MARINE... East northeast winds dominate through Saturday with 1-3ft waves for the western and central basins of LAke Erie. Beyond that through early next week, expect varying wind directions thanks to several frontal systems coming through the region. Despite some onshore winds at times, wave heights should remain in the 1-2ft range or less for the bulk of the forecast. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. NY...None. MARINE...None. && $$ SYNOPSIS...KEC NEAR TERM...KEC SHORT TERM...26 LONG TERM...26 AVIATION...KEC MARINE...26 ####018005994#### FXUS64 KSJT 031127 AFDSJT Area Forecast Discussion National Weather Service San Angelo TX 627 AM CDT Fri May 3 2024 ...New AVIATION... .SHORT TERM... (Today and tonight) Issued at 336 AM CDT Fri May 3 2024 ...Severe weather expected again this afternoon and evening... Even with the showers and thunderstorms we've seen over the past few days, moisture is still plentiful across the area. Low clouds are already overspreading much of the area early this morning and should stay in place through the mid/late morning before mixing out. As the boundary layer warms through the day, we will see large scale destabilization across the area. With dew points ranging from the mid 60s to lower 70s, MLCAPE values by early afternoon will be on the order of 3000-4000 J/kg. Similar to the past few days, shear is still going to be on the more marginal side, especially in the low to mid levels around 30-35 kts. Storms are expected to initiate off of the dryline which should be in the vicinity of the Permian Basin by mid afternoon. Storms will likely go up quickly should remain discrete initially. Very large hail will be the main threat with the initial development along with a subsequent damaging wind threat. While the tornado threat is generally on the low side thanks to weak low level flow, we will have to watch boundary and storm scale interactions as these may be able to enhance local conditions and make tornadic development more favorable (similar to what we saw yesterday). Storms are expected to grow upscale with time, likely becoming a more linear feature where a transition to more of a wind threat is expected. Though, given the favorable thermodynamic profiles, large hail will still remain possible through the duration of the storms lifecycle. These storms will be efficient rainfall producers as noted by Pwat values over 1.25 for nearly the entire area. Though the storms should be moving fast enough to limit flash flood potential, many of our northern and eastern counties are already decently saturated thanks to rain events over the past week or 2 so it won't take much to potentially create some problems. High temperatures today will range from the lower 80s across the Big Country and Heartland, locations that will remain socked in cloud cover for longer, to the lower 90s in the Concho Valley and along the I-10 corridor. Clouds will rebuild across the area tonight, behind the storms, keeping low temperatures mild in the 60s. && .LONG TERM... (Saturday through Thursday) Issued at 336 AM CDT Fri May 3 2024 Severe weather and heavy rainfall will continue to be the main issued through the weekend, ahead of unusually hot conditions for next week. Air mass remains very unstable for Saturday ahead of a weak cold front and a shortwave trough approaching from the west. Most models depict fairly widespread thunderstorm initiation by Saturday afternoon across the Permian Basin and South Plains and then quickly rolling into West Central Texas late in the afternoon and into the evening hours. Widespread convection may end up decreasing the severe threat, but increasing the heavy rainfall threat. Right now, appears the greatest severe threat will be across the Concho Valley west into the Permian Basin and Trans Pecos ahead of the front and in an area that may see a little more sun before the storms develop. By Sunday, multiple rounds of convection may begin to take its toll on the air mass and make it a little harder to destabilize. Widespread convection once again though with the remnants of the frontal boundary draped across the area. Highs may still in the upper 70s and lower 80s across the area. Rainfall totals for Saturday and Sunday will begin to add up, and portions of the area will see very heavy rainfall. Where is the question, and does the heavy rainfall occur on areas that have already seen some decent totals over the last week. No Flash Flood Watch at this point, but after we see where todays convection ends up, we may need to consider something. Main upper level trough pushes across the Southern Plains by Monday afternoon, leaving a ridge aloft to set up across the area. Latest model blends are showing mid to upper 90s by Wednesday and Thursday as dry and hot pattern prevails. && .AVIATION... (12Z TAFS) Issued at 625 AM CDT Fri May 3 2024 Fairly widespread MVFR to LIFR ceilings have covered the area. It's not as dense as initially indicated with scattered VFR ceilings poking through every once and awhile. Visibilities range from VFR at KABI and SJT to LIFR at KBBD. These will likely lift into the high-end IFR to VFR range in the coming hours. All sites should see ceilings lift back to VFR between 16-18Z (maybe earlier if the breaks in cloud cover continue). Winds will be out of the east to southeast today with some sites seeing gusts to around 20 kts by late afternoon. Chances for showers and storms return late this afternoon and evening across the area. Have given a first guess at timing for the sites but this will most likely need to be refined and updated with further hi-res guidance. Sub-VFR ceilings are expected to build back in after the storms though there remains uncertainty in just how low these ceilings will go. && .PRELIMINARY POINT TEMPS/POPS... Abilene 83 62 80 61 / 30 40 70 90 San Angelo 90 64 85 63 / 30 30 60 80 Junction 92 67 87 65 / 20 20 30 70 Brownwood 83 66 81 63 / 20 30 60 80 Sweetwater 84 62 79 61 / 40 50 80 90 Ozona 89 65 84 63 / 30 30 40 70 Brady 84 65 81 63 / 20 30 50 80 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...50 LONG TERM....07 AVIATION...50 ####018004961#### FXUS64 KLUB 031127 AFDLUB Area Forecast Discussion National Weather Service Lubbock TX 627 AM CDT Fri May 3 2024 ...New AVIATION... .SHORT TERM... (Today and tonight) Issued at 343 AM CDT Fri May 3 2024 Another round of strong to severe thunderstorms are possible this afternoon and evening along and east of the dryline as the left exit region of an 80 knot jet streak moves over West Texas (not particularly strong for jet level winds but is probably aiding in enhancing large scale lift). Low level moisture will continue to advect into the forecast area which will maintain surface dewpoints in the mid-60s in the Rolling Plains and southeast Texas Panhandle and mainly in the 50s for areas on the Caprock which again will prime the lower atmosphere for thunderstorms. Strong to severe thunderstorms are likely to form along the dryline in the afternoon and evening with forecast MLCAPE exceeding 3000 J/kg and deep layer shear of about 40 knots in the moist sector supporting supercells capable of very large hail. Forecast tornado parameters (low level helicity) are not very impressive but a tornado cannot be ruled out in a well organized supercell. CAMs suggest initial discrete supercells which could produce very large hail and damaging winds. If storms continue to form, they may congeal into an MCS and begin to move east out of the forecast area. 3 AM satellite imagery shows patchy low level stratus across the southwest Texas Panhandle and portions of the Rolling Plains. This low level cloud cover is expected to continue to expand in coverage this morning with the low level moisture advection. Latest model guidance indicates these clouds will clear or become patchy by the afternoon allowing surface temperatures to climb into the 80s for these areas. However, if stratus hangs around through the afternoon, thunderstorms may struggle to initiate. && .LONG TERM... (Saturday through Thursday) Issued at 343 AM CDT Fri May 3 2024 The greatest forecast challenge in the long term remains a potentially stronger and faster FROPA on Saturday morning which may ultimately shift the heaviest rainfall farther south and southeast of our domain by later in the day. Nevertheless, the overall pattern by Saturday afternoon and evening remains favorable for widespread measurable rain in the wake of a morning FROPA which should slow or stall as it reaches the I20 corridor by the afternoon. Moist E-NE sfc-850 mb flow following FROPA along with an uptick in southerly moisture advection at 700 mb preceding a shortwave trough later in the day will all help push PWATs to 0.5" to 0.75" above normal. Given the abundant post-frontal stratus and the front stalling to our south, NBM's high temps were nudged lower and closer to the more representative MOS. Despite this, soundings still depict ECAPE around 1000 J/kg on average across the southern half of the CWA which could spur at least a marginally severe hail threat, although the greater threat remains heavy rainfall given anomalously high PWATs and improving ascent from the afternoon into the evening. Heavy rain probabilities are almost always trickiest with cellular convective modes such as this event as opposed to MCSs, so we won't get too invested in messaging 1" or greater rainfall probabilities particularly given considerable spread still evident in the LREF's QPF. NBM's PoPs were scaled 10-20% lower beginning late Saturday night through the day on Sunday to account for stronger subsidence/height rises behind the upper trough. This drying should eventually secure some sunshine by Sunday, although lingering moist upslope flow will undoubtedly delay this process until later in the day and curb high temps. Deeper drying and windier conditions unfold on Monday as a vigorous upper low turns negatively tilted to our north and sweeps the dryline off the Caprock where some low PoPs remain. Uneventful weather then sets up from Tuesday and beyond south of a deamplifying upper trough, yet some re-amplification to this trough from Wed-Thu looks to send us a healthy dose of Canadian air with below-normal highs by the end of the week. && .AVIATION... (12Z TAFS) Issued at 627 AM CDT Fri May 3 2024 Widespread IFR stratus with occasional LIFR decks should gradually erode and give way to VFR by early afternoon at LBB and PVW as a dryline draws closer. CDS meanwhile is unlikely to see any improvement beyond MVFR in this very moist upslope pattern. Latest signals for late day TS are now favoring areas SE of LBB, though ISO TS will be possible along the extent of the dryline through this evening. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...17 LONG TERM....93 AVIATION...93 ####018004363#### FXUS63 KFGF 031128 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 628 AM CDT Fri May 3 2024 .KEY MESSAGES... - A few weak thunderstorms possible north of Highway 2 this afternoon then a nice weekend in store. - First chance of the season for organized thunderstorms arrives Monday/Tuesday. && .UPDATE... Issued at 627 AM CDT Fri May 3 2024 Showers continue to shift north and east affect just the northern tier of counties along the intl border with the low now centered in far southwest Ontario. No changes to the forecast with all aspects on track. && .DISCUSSION... Issued at 322 AM CDT Fri May 3 2024 Showers coming to an end for most this morning with a few remaining along the international border yet. Clouds continue to clear quickly behind the rain with at least a few hours of sun likley south of HWY 200 today. Along HWY 2 and north another piece of energy will rotate around the parent trough with associated PVA and low level cold air advection causing the formation of scattered showers/thundershowers across northern areas this afternoon. Resulting CAPE from the steepening lapse rates could top 100-200 j/kg. Not unreasonable to see some small hail with this though shallow storm tops to <6km and minimal depth in the HGZ would likely limit any hail that does occur to pea size. Not expecting much in terms of rain accumulation this afternoon with the 25th/75th showing 0.10" to 0.25" primarily north of HWY 2 though a few of these showers depending on the exact track of the wave could make it a bit further south towards HWY 200. This evening a band of h850 fgen in South Dakota will shift east bringing shower chances across the far southern valley into west central Minnesota though a quick forward speed should limit amounts to under 0.25". Shortwave ridging then begins to move in behind this pair of Friday waves with the bulk of the clouds clearing through the day on Saturday leaving a nice end to the weekend with highs climbing into the 60s and an outside chance (10%) at 70s in the valley. The nice weather doesnt last long however as another upper low barrels east from the rockies becoming very negatively tilted as it reaches the Dakotas Monday. 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 wil also usher in strong moisture return from stemming from the Gulf of Mexico ahead of the low. CWASP values are currently forecast to be the highest we have seen yet this year with CSU ML highlighting our area in a 5% chance for severe weather. Whether this threat materializes will remain to be seen but between the strong kinematics and moisture return at least a few necessary ingredients will likely be in place. Taking a step back and just looking at QPF probs best chances for over 1" look to be in western and central North Dakota through Wednesday AM. 25th/75th would generally result in 0.5-1.5" for the forecast area. 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 /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 627 AM CDT Fri May 3 2024 Once clouds clear TVF in the next hour all sites will be briefly VFR this morning before a SCT/BKN deck at 020-030 moves in for northern sites. Winds quickly pick up this morning with strong cold advection and eventual shower activity beginning by the early afternoon for DVL/GFK/TVF/BJI. Could showers stay north and be a non factor but error on side of caution. Gusts to 25 kts this afternoon will die off around sunset with MVFR OVC for FAR/BJI tonight. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...TT DISCUSSION...TT AVIATION...TT ####018007074#### FXUS63 KBIS 031128 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 628 AM CDT Fri May 3 2024 .KEY MESSAGES... - Expect low to medium chances (20 to 60 percent) for rain showers through the day, mainly across the northern half of western and central North Dakota. Some light snow may mix in across the west this morning. - Temperatures will warm through the weekend, with windy conditions on Sunday. - Chances for rain return Sunday evening and continue through the work week. The wettest period will Monday through Tuesday when most of western and central North Dakota will see medium to high chances (60 to 90 percent) of rain. && .UPDATE... Issued at 622 AM CDT Fri May 3 2024 The forecast looks to generally be on track this morning. We have seen a few radar echoes across the northwest and north central, potentially bringing a few rain drops to the surface as they pass overhead. Some more substantial showers have been observed on the Williston radar over the past couple of hours, extending from around Culbertson Montana southeast down to around Grassy Butte. More showers should continue to develop across the northwest and north central through the day. No major changes were needed for this update. && .DISCUSSION... Issued at 333 AM CDT Fri May 3 2024 Early this morning, western and central North Dakota sits under the influence of broad quasi-stationary troughing overhead. The upper low that brought showers and thunderstorms to the region yesterday will continue to eject out into Ontario to our northeast as the next upper low rotates down into northwest North Dakota from southern Saskatchewan later today. This low will be the trigger for showers to develop through the day (20 to 60 percent chance), mainly across the northern half of the forecast area (best chances along the International Border). Some light snow may even mix in across the west briefly this morning. RAP soundings suggest that instability will be limited this afternoon and evening with MUCAPE values mainly maxing out in the 100 to 200 J/kg range. While a stray rumble of thunder or two cannot be ruled out, confidence is not high enough to include mention of thunder in the gridded forecast at this time. Precipitation chances will diminish to the northeast tonight as the upper level trough finally starts to move out to our east, transitioning western and central North Dakota into northwest flow aloft on Saturday. Surface high pressure will also slide in on Saturday, leading to diminishing clouds from west to east and slightly warmer temperatures. Highs will remain cool today, ranging from the mid 40s northeast to the mid 50s southeast and then by Saturday, highs will range from the lower 50s to lower 60s. An upper level ridge axis then approaches Saturday night and crosses the state on Sunday. This will mean even warmer temperatures with forecast highs ranging from the lower 60s to lower 70s. Behind the ridge axis, a deep trough will approach from the west, transitioning western and central North Dakota into meridional flow aloft. As this trough approaches, a surface low will deepen to around 990 mb or less over eastern Montana. This will lead to strong warm air advection, pressure falls, and a rapidly tightening pressure gradient on Sunday for our area. So, while highs will be fairly mild, it will be windy with soundings suggesting the potential for 40 knots or so available to mix down from the top of the mixed layer. The potential for gusts up to 45 mph seems reasonable for now and an eventual Wind Advisory seems like a decent probability. The story then turns to the approaching strong storm system and widespread rain event Sunday night through the week. The sub 990 mb surface low will continue to deepen as the upper level trough starts to take on a negative tilt and nudges into the northern Plains. Widespread showers and some thunderstorms will develop through the day and night, but dry slotting is likely to setup somewhere depending on the eventual track of the low. While thunderstorm chances will be better than in previous days, instability still appears to be somewhat lacking. However we could see some MLCAPE values up to 500 J/kg with deep layer shear forecast to range from around 35 to 45 knots. So, the severe weather potential appears to be fairly low but a couple of strong storms may be on the table. The wettest period will generally be Monday through Tuesday (widespread 60 to 90 percent chances for showers) and another potential hazard could be heavy rain, especially if heavier showers/storms can train over some of the same areas. NBM 72-hour probabilities (ending 12z Thursday) don't suggest anything too dramatic with most of the west and central in medium probabilities (40 to 70 percent) for an inch of rain or more (the one exception being the James River Valley where the consensus currently wants to place most of the dry slotting). When we increase that threshold to two inches, the probabilities fall off mainly into the 10 to 30 percent range. However, it is worth noting that the NAEFS is showing Integrated Water Vapor Transport, PWATs, and 850 mb specific humidity in the 97.5th percentile or greater for this time of year in the Monday through Tuesday time frame. Thus, there may be an opportunity here for some heavier rainfall in a few locations. The upper low will start to wind down by mid week but will be slow to kick out into the Great Lakes region given a stubborn east coast ridge. Low to medium chances (20 to 60 percent) for showers will continue through at least Thursday. Highs on Monday will not be quite as warm as Sunday given widespread clouds and rain. However, we should still see highs in the 60s. With the cool wet pattern continuing, highs will mainly dip back into the lower 50s to lower 60s for most of the rest of the work week. && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 622 AM CDT Fri May 3 2024 Scattered showers will continue to increase in coverage over the northwest and north central today, but will generally be of the hit and miss variety. With such uncertainty about eventual location and tracks of these showers, we elected to keep mention of rain out of any specific site forecast except for KXWA where confidence is a bit higher. IFR to MVFR ceilings will be likely across the west and north through much of the period, including KXWA, KDIK, and KMOT. For now, it appears that KBIS and KJMS should remain in VFR categories through the period. Winds will become a bit gusty out of the west this afternoon, when we could see some gusts up to 30 mph or so. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...ZH DISCUSSION...ZH AVIATION...ZH ####018007372#### FXUS63 KDMX 031129 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 629 AM CDT Fri May 3 2024 ...Updated for the 12z Aviation Discussion... .KEY MESSAGES... - Early Morning Fog...Patchy to Areas Dense Fog through 8am - Showers & Storms Tonight and early Saturday || Dry Sunday - Storms Return Monday Evening With Some Severe Risk - Sun/Cloud Mix with passing Showers Much of Next Week; Turning Cooler by weeks end. && .DISCUSSION... Issued at 312 AM CDT Fri May 3 2024 .Short Term /Today through Saturday/... Confidence Short Term: Medium to High Active weather pattern for much of the seven day period, though we may luck out a few days next week with precipitation south/north of us. Rainfall is still needed in some areas, but not the southeast. The filling low that brought the moderate to heavy rainfall to the region yesterday has now migrated to the far Northern Plains. We had a front at H850 still over the eastern counties of the state at 00z, but that has now edged east a bit since then. Another weak area of low pressure is located near Springfield, MO at H850 with a third area of low pressure in northern New Mexico. The Gulf moisture stream has temporarily been pushed south of our area. However, a large plume of +10C to +15C dew points is just south of the region at this time. Meanwhile a weak ridge of high pressure will cool the boundary layer through early morning. Weak winds and ample boundary layer moisture from yesterdays rainfall continue to promote fog development. This will likely peak around 5 to 7 am over the area. Have updated the grids for areas of fog into the morning commute and will address conditions with either an SPS or maybe an advisory if it looks more problematic before 4 am. After the fog burns off, we will be rewarded with a rather pleasant day to round out an active week. Highs today with patchy fair weather cumulus will reach the lower to mid 70s as south southeast winds increase to 10 to 15 mph by mid to late afternoon. Tonight a wave currently showing up on water vapor imagery over Colorado/Idaho will track east. This will pull an area of low pressure and front east. At the same time, the moisture plume to our south will be pulled back northeast overnight. PWATs again increase to around 1.25 inches and warm cloud depths increase to over 10kft again from 06z to 18z Saturday. The models continue to indicate the main forcing at H700/H500 will peak from 06z to 12z across the area. As the wave reaches to near the IA MN border and the LLJ weakens significantly overnight, the showers and storms will weaken with time from 06z to 12z. Lesser rainfall is anticipated in the southeast, with amounts northwest of there from .75 to 1.5 inches and in the southeast about a quarter inch. Severe weather chances tonight are not high, but the southwest to the south central has some risk of an isolated stronger storm with a small risk of wind/hail. Shear is just strong enough for some rotation. Lows tonight will fall to the mid 40s northwest to the mid 50s in the far south. The lingering showers and isolated storms early tomorrow will generally exit the east by mid afternoon as high pressure builds south and east from the Northern Plains. We will be fighting lingering clouds in the afternoon mixed with some peaks of sunshine. Highs will reach the lower 60s northwest to the lower 70s southeast. .Long Term /Saturday Night through Thursday/... Confidence: Medium Saturday night will be similar to this morning. Clearing skies may lead to some patchy fog once again. We will need to address that on Saturday to see how much dry air is advected southeast into the state. Otherwise, Sunday will be dominated by high pressure slowly drifting east by late afternoon. Other than some fair weather clouds, the day will again be very pleasant. H850 temperatures begin to warm due to return south flow. This will help push highs into the upper 60s to lower 70s by afternoon. We continue to see a southern stream wave in the southeast on Sunday, but there is really no sign of any moisture return across Iowa at that time, so have removed any mention of precipitation. Lows Sunday night dip to the 40s to lower 50s. A large scale trough over the western CONUS will begin to move east on Sunday. This feature has been consistently forecast by the medium range models to form an elongated trough with a double barrel low; one migrating to Alberta and the southern one wrapping up nearer eastern Nebraska. As the entire system deepens and occludes, the southern stream low will pull a wing of moisture/instability into the area later Monday afternoon and into the night. An impressive jet max will increase collocated columnar wind fields from H850 up to H500 by 06z Tuesday over the area. Winds will average 50-65kt through the column with some diffluence at H300. This, along with enough wind shear and instability to promote some rotation as well as a potential QLCS wind and tornado threat overnight. Obviously, we have several days and some changes may occur. Highs Monday will be mild ahead of the system with 70s across the board. The Euro and GFS are beginning to diverge a bit by Tuesday; GFS faster and the Euro slower. The Euro shows only a quick break early Tuesday from the overnight convection, with another speed max forecast to plow into an area of lingering instability across Iowa. This would tend to promote another area of strong to severe storms over mainly eastern Iowa and states east and northeast of our area. At this time, no solution is favored but the GFS generally trends too fast by days 4 to 5. Will need to remain aware of a second potential round of stronger storms later Tuesday near our area. Tuesdays highs are going to be difficult to nail down for a few days, due to the various solution differences. The most likely range would be the 60s northwest to the 70s southeast. There is some consensus for Wednesday into Thursday with regard to the Northern Plain system evolution. It appears that the large scale system will drift back into the Midwest with more clouds, some passing showers and cooler temperatures by the end of the period. Highs should generally be in the 60s to around 70 by Thursday with 70s still likely on Wednesday. There is some indication that more clouds and cooler conditions will persist late into the week and the following weekend. && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 628 AM CDT Fri May 3 2024 Fog continues early this period with some VV through 13z, then fog mainly burning off between 13 and 14z over the region. Otherwise, expect light winds and fair wx cu today. Showers and storms arrive aft 06-08z west and move east through remainder of period. Cigs will also lower to MVFR west half by 12z Saturday. && .DMX WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 8 AM CDT this morning for IAZ006-007- 016-017-024>028-035>039-044>050-057>062-070>075-081>085-092. && $$ DISCUSSION...REV AVIATION...REV ####018002182#### FXUS62 KTBW 031129 AFDTBW Area Forecast Discussion National Weather Service Tampa Bay Ruskin FL 729 AM EDT Fri May 3 2024 ...New AVIATION... .AVIATION... (12Z TAFS) Issued at 727 AM EDT Fri May 3 2024 Prevailing VFR conditions with winds less than 12 knots expected through the forecast period. Rain and storm chances remain on the low side, so will not include any mention of SHRA or TSRA at any of the terminals at this time. && .SHORT TERM (TDY-Tonight)... Issued at 455 AM EDT Fri May 3 2024 Other than a few clouds decorating the skies along the Nature Coast, it is a mostly clear morning across the Florida Peninsula. Ridging aloft and surface high pressure remains in place today. This should keep light easterly winds in place with the afternoon sea breeze shifting winds onshore. Slightly drier conditions are anticipated which should limit how much activity, if any, develops today. Most of the guidance keeps the highest chances across souther parts of the state. In addition, afternoon temperatures will be around 90 degrees, so residents and visitors should stay hydrated to prevent any heat related illnesses. && .MARINE... Issued at 439 AM EDT Fri May 3 2024 Area of high pressure remains in control over the Gulf waters through the period. Fairly dry conditions are anticipated today. Winds should remain 15 knots or less and seas 2 feet or less making for pleasant boating conditions through the week. A sea breeze is expected close to the coast each afternoon and evening. A weak front to approach portions of the area during the weekend, but highest chances of rain are expected to be over land. && .PRELIMINARY POINT TEMPS/POPS... TPA 90 71 89 73 / 0 0 20 20 FMY 91 70 90 70 / 10 10 40 20 GIF 91 68 91 69 / 0 0 20 20 SRQ 90 71 89 71 / 0 0 20 20 BKV 92 64 91 65 / 0 0 20 20 SPG 88 73 87 74 / 0 0 20 20 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ AVIATION...Wynn DECISION SUPPORT/UPPER AIR...Hubbard