####018008097#### FXUS61 KBTV 040444 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 1244 AM EDT Sat May 4 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 SUNDAY/... As of 1238 AM EDT Saturday...Southerly flow is preventing temperatures from falling quickly across the Champlain Valley and parts of northern New York so had to bump them up a little. Rain showers are trying to enter the St. Lawrence Valley but most of them have not been able to reach the ground so trimmed PoPs slightly. Clouds are slowly lowering from west to east and this should continue for the rest of the night. Overall, the forecast is mostly on track so all the edits were minor. Previous discussion follows Previous discussion...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 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 /06Z 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/Myskowski SHORT TERM...Chai LONG TERM...Chai AVIATION...Kremer/Kutikoff ####018004479#### FXUS63 KFGF 040447 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 1147 PM CDT Fri May 3 2024 .KEY MESSAGES... - First chance of the season for organized thunderstorms arrives Monday/Tuesday, with isolated stronger storms possible. && .UPDATE... Issued at 1142 PM CDT Fri May 3 2024 Area of light rain just brushing the far southeast fcst areaa from Wadena to Elbow Lake. This will likely continue til late tonight then move off to the east after sunrise. Otherwise mid/high level moisture streaming to the northeast over the southeast 1/2 of the fcst area. Meanwhile upper level trough over central Canada with several weak short waves thru Saskatchewan and into SW Manitoba, northwest ND. The later is still bringing some light rain showers to Bottineau area and north/west with area of clouds as well along the ND/Manitoba border. This wave likely to slowly move east tonight and will keep slight chc of showers along the Intl border overnight. 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 /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1142 PM CDT Fri May 3 2024 VFR ceilings area over the area with mix of mid/high clouds southeast 1/2 of the fcst area and some mix of high end MVFR/low VFR clouds near the Canadian border. Some of these clouds in the north will sink south and ceilings may lower into more consistent MVFR range DVL-TVF zone and maybe GFK for a time late tonight or Sat morning. West or northwest wind 5 to 15 kts thru the pd. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Riddle DISCUSSION...MM AVIATION...DJR ####018006790#### FXUS66 KMTR 040449 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 949 PM PDT Fri May 3 2024 ...New AVIATION... .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. && .UPDATE... Issued at 907 PM PDT Fri May 3 2024 The forecast for the incoming low pressure system remains largely on track with minimal changes. HRRR guidance shows the low slowing down slightly with rain arrival times pushes back by an hour or two. Rain will arrive during the early to late morning hours moving north to south. Based on HRRR guidance, the most likely arrival times are 3AM- 5AM for the North Bay, 7AM-10AM for the East Bay and South Bay, and 8AM-11AM for the Central Coast. Rainfall totals look largely the same with between 0.5-1.0 inches expected in the Bay Area and 0.2- 0.5 inches expected in portions of the Central Coast. Locally higher precipitation totals are expected in the coastal North Bay mountains and the Santa Cruz mountains. Gusty winds will extend inland from the coast as the system passes with gusts between 25-30 mph possible. Trend for below average daytime and overnight temperatures tomorrow through the early work week remains on track. && .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... (06Z TAFS) Issued at 942 PM PDT Fri May 3 2024 MVFR/IFR level clouds are moving inland. Winds are reducing and are expected to become light to moderate, then slowly turn to become more S/SW ahead of the approaching low pressure system. By the mid morning, 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 lift slightly as the rain approaches. Rain continues into Saturday afternoon before dissipating, with winds turning to W/NW and becoming breezy. Expect these breezy winds to last into Saturday night. Vicinity of SFO...IFR and breezy into the night. 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 visibility. Winds turn to become W/NW in the later morning, but rain lasts through the afternoon. VFR returns behind the rain band, with breezy westerly winds. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...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. VFR returns behind the main rain band with breezy winds easing into the late night. && .MARINE... (Tonight through next Thursday) Issued at 907 PM PDT Fri May 3 2024 Expect breezy to gusty northwest winds to 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 from 9 AM to 9 PM PDT Saturday for Pigeon Pt to Pt Pinos 0-10 nm. Gale Warning until 9 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 ####018007284#### FXUS63 KGLD 040450 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 1050 PM MDT Fri May 3 2024 .KEY MESSAGES... - Fire weather concerns return Monday through Thursday for most of the Tri-State area, but favor along and south of I-70. - Thunderstorms, a few of which may become strong to possibly severe, will be possible Monday afternoon/evening. && .UPDATE... Issued at 1012 PM MDT Fri May 3 2024 The entire CWA has been cleared from earlier Severe Thunderstorm Watches. Most of the area is not seeing any precip at this time, and the remaining eastern zones seeing activity is seeing sub severe returns on radar. Still could see gusts 40-50 mph in the remnants as they exit, but severe wx is done for this night. Have added in Fog for all areas, along with patchy frost in the NW. && .SHORT TERM /THROUGH MONDAY NIGHT/... Issued at 130 PM MDT Fri May 3 2024 Not much has changed from previous thinking with two areas of concern for the remainder of the afternoon and this evening. Convective initiation has occurred in eastern Colorado near Las Animas. HRRR shows this activity expanding into northeast Colorado south of I-70 and northwest Kansas over the next few hours. Latest analysis and forecast of SBCAPE shows 1500-2000 j/kg available along with effective bulk shear values of 40-50 kts. Those parameters should be sufficient for a few severe thunderstorms capable of producing large hail, damaging winds and perhaps a tornado with any discrete supercell. Further north, initiation has also occurred along the cold front in the Nebraska panhandle. As the cold front surges south this evening, convection will increase rapidly into a line capable of producing damaging wind gusts. Given the same parameters above, a few embedded cells in the line will also be capable of producing large hail and a brief tornado. The front will exit the area by around 06z ending the severe threat, though a few showers and storms may linger past 06z in southern and eastern areas. Mean precipitation amounts for the event range from around a tenth to a quarter of an inch in Colorado, a quarter to a half inch west of Highway 83, and around a half inch east of Highway 83. The higher percentiles show locally up to 1 inch possible in just about the entire area, with up to about 1.5 inches in northeast corner (McCook, Oberlin, Norton) and southern areas (Tribune, Leoti). Winds will gradually diminish overnight with low temperatures ranging from the lower 30s in Colorado to the lower 40s in north central Kansas. Saturday will be mostly sunny and breezy with just a hint of shortwave ridging aloft ahead of weak shortwave in southeast Colorado. High temperatures will be in the lower 60s. Saturday night now looks dry with the shortwave staying south of the area. There will be some increase in clouds with low temperatures in the lower 40s. Models do hint at fog developing in western portions of the area late Saturday night into Sunday morning (along the Kansas and Colorado border area and westward). Southwest flow aloft continues on Sunday with embedded weak waves which may result in a few isolated showers and thunderstorms by Sunday afternoon. There is a very narrow corridor of weak instability forecast along the Kansas and Colorado border area with a 100-200 j/kg currently indicated. So, not expecting any severe storms should any develop. High temperatures will be in the upper 60s to lower 70s. Shower and thunderstorm chances increase going into Sunday night with height falls ahead of the approaching trough and nocturnal low level jet. MUCAPE increases overnight to 1500-2000 j/kg with shear values of 40-50kts. So may see elevated thunderstorms late with a risk for hail, but confidence is low at this time range. Low temperatures will be in the 50s. Main trough axis ejects out of the Rockies and across the plains with a negative tilt on Monday. Surface low will deepen in the Nebraska panhandle with the dry line trailing south into the forecast area. The dry line will be the focus for convective initiation in the afternoon and the models indicating the dry line will likely be in eastern areas at least for a few hours before moving east. Timing of initiation will be critical, but if it happens before the dry line moves out may see a short window for severe storms along/east of Highway 83. Instability and shear will be more than adequate for a risk of large hail, damaging winds and tornadoes. West of the dry line may see few wraparound high based showers, but no severe threat. However, afternoon relative humidity values will be dropping to near critical or critical values and wind speeds also appear to meet critical thresholds for fire weather concerns. Precipitation should be east of the area Monday night. High temperatures will range from the upper 60s in Colorado to the upper 70s in north central Kansas and lows Monday night in the upper 30s to lower 40s. && .LONG TERM /TUESDAY THROUGH FRIDAY/... Issued at 153 PM MDT Fri May 3 2024 Tuesday, an upper trough will be in place over the High Plains and Central High Plains. Models continue to show variations in the placement of a low pressure system ranging from Nebraska to the Dakotas. Kept winds where they are for now due to continued uncertainty on the location of the low, but wouldn't be surprised if later model runs start to bring up wind potential a bit. Zonal flow will be in place over northwestern Kansas and eastern Colorado through the day. Expected highs will range from the upper 60s in portions of Yuma and Kit Carson counties to the mid to upper 70s south of I-70. Wednesday, a disturbance will move across the Dakotas and Nebraska. We are currently forecast to stay dry through the daytime hours. Some cooler air will move in, with highs ranging from the mid to upper 60s in eastern Colorado to the upper 60s to low 70s in Kansas and Nebraska. Heading into the evening and overnight hours, there will be a 10-20% chance of a few showers and thunderstorms, mainly for areas along and west of the Colorado state line. Thursday, the disturbance will continue to move to the east, with low end chances (10-30%) of shower and thunderstorm activity. For the time being, areas west of a line from McCook to Tribune stand the best chance of receiving precipitation with this system. Expected temperatures will be in the 60s for highs and the 30s and 40s for lows. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1045 PM MDT Fri May 3 2024 Both terminals will see MVFR fog/ceilings that are expected to impact the terminals through at least through 14z-16z, before going VFR. Winds northerly around 20-30kts, diminishing to around 10-15kts by 10z, then eventually veering southeast from 21z onward. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ UPDATE...JN SHORT TERM...024 LONG TERM...Wekesser AVIATION...JN