FXUS61 KBTV 192351 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 751 PM EDT Fri Apr 19 2024 .SYNOPSIS... Scattered showers and breezy conditions will continue this evening into Saturday. Although Sunday and Monday will trend drier, it will be unseasonably cool, especially Monday. Temperatures will begin to moderate on Tuesday, with rain chances increasing over the middle of the week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... As of 724 PM EDT Friday... Forecast remains very much on track. Broad 1020 mb surface high draped from Long Island to just east of Nantucket coupled with a 1000 mb triple point surface low centered over the southern tip of Hudson Bay means that the south or east southeast winds gusting 25 to 30 mph, locally 35 mph, will remain widespread through the early overnight hours. PREVIOUS DISCUSSION... A weakening occluded front is currently sliding east. Some sprinkles are making it to the ground here in the northern Champlain Valley, but the bulk of precipitation resides in northern New York. Overall, still not looking at much in terms of amounts at about 0.10" or less, and generally favoring northern New York. Temperatures are just slightly below season normals across the region, with 50s and even some spot 40s. Winds have been breezy, although not gusting too much. Later this evening, a low-level jet will maximize over the area, channeled mainly across the Champlain Valley. About 6 PM to 10 PM, we could see some brief 30 to 40 mph gusts along Lake Champlain, before trending back down to the 15 to 25 mph it has been most of the day. Negative thickness advection and the upper trough pivot into the region overnight. Along the boundary, there could be a brief resurgence of precipitation from the southwest that will generally stream along the Connecticut River Valley, but some guidance has some light rain making it as far north as the northern Champlain Valley. Overall, additional precipitation should again be light. Abundant clouds and south flow will keep temperatures warm overnight, with mid 30s to mid 40s. On Saturday, we're still poised for a very strong upper trough to pull some moisture off Lake Ontario to produce conditional instability across the region. Model progged CAPE of 150 to 250 J/kg with steep lapse rates should produce scattered showers, especially across the St. Lawrence Valley and northern Vermont. Low-level conditions will be dry, and showers could drive gusty winds up to 35 mph to the surface, while background flow remains about 15 to 25 mph. With such cold temperatures aloft and potential for evaporative cooling, some of these showers will produce pea sized hail or graupel. The greatest concentration of activity will be over northern New York and far northern Vermont, which will lead to cooler high temperatures in the mid 40s to around 50. In the lower Champlain Valley and Connecticut River Valley, fewer showers should allow temperatures to warm into the mid to upper 50s. Shower activity will decline after sunset and the vort max shifting east overnight. Despite lack of clearing, the cold advection should drive temperatures just below seasonal normals, with mid 20s to mid 30s. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 344 PM EDT Friday...A couple of waves will be moving through Sunday and Sunday night. The first will be weak since best forcing remains in northeastern Canada; potential for isolated showers will be limited mainly to locations towards the Canadian border. More notably, the pressure gradient will be tightening through the day supporting increasing winds as a sharper front moves through overnight. Southwest gusts 20 to 35 mph will be possible late afternoon through the evening. The sharper cold front overnight will be mostly dry for central/southern Vermont and Essex County of New York, but will bring 10-40% chances of low elevation rain showers and snow showers for elevations above 1800 feet. Cold air advection will be ample with overnight lows dipping below freezing into the 20s for the Adirondacks/northeaster Vermont and upper 20s/low 30s elsewhere. As such, wind chills will be in the teens to 20s; quite a departure from recent relative warmth. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 344 PM EDT Friday...Model guidance continues to favor a progressive upper level pattern with passing ridge/troughs swinging temperatures widely. Portrayal of the mid week low continues to show robust development with strong warm air advection on Tuesday, potentially into the mid/upper 60s, followed by widespread freezing overnight lows Wednesday and Thursday nights. While below seasonal averages, the anomalies for temperatures are generally around to less than 1 standard deviation which is not obscenely unusual for this time of year. The projected evolution of the low suggests potential for gusty winds associated with a strong low level jet which should be sufficient for gusts 20- 30 mph for most spots with channeled areas approaching 40mph. Fortunately, the upper pattern remains progressive enough to keep widespread heavy rainfall chances limited - still estimated to be generally less than 0.5"; can't rule out some thunderstorms ahead of the frontal boundary, but those details will become better known over the next 24 hours when we move into mesoscale model time windows. With the low exiting by Friday, shower chances will diminish except some lingering upslope showers remaining possible. Heights will be rising, however, so temperatures should be trending back towards seasonal averages. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Through 00Z Sunday...Terminals are a mix of VFR and MVFR due to ceiling height and that should continue to be the case for the first part of the night. Ceilings at RUT could drop to IFR for a couple hours but it currently seems unlikely. There have been on and off showers this evening but they will become less frequent overnight and should be out of the region by daybreak. Ceilings will begin to rise after these showers move out and all terminals should be VFR by daybreak. VFR conditions should then persist through the rest of the day. Winds are currently relatively strong, with gusts up to 25 KTs at BTV, SLK, PBG, and MSS. However, winds will weaken quickly this evening and gusts should generally stay under 10 KTs for the later part of the night. Winds will pick back up during the day tomorrow but gusts are expected to be under 20 KTs. Winds will slowly shift to more westerly as the night progresses and into the day tomorrow. While wind shear is only expected to meet LLWS criteria at SLK, there will still be relatively strong wind shear at the rest of the terminals, just not strong enough to meet the criteria. Outlook... Saturday Night: VFR. NO SIG WX. Sunday: VFR. NO SIG WX. Sunday Night: VFR. Slight chance SHRA. Monday: VFR. NO SIG WX. Monday Night: VFR. NO SIG WX. Tuesday: VFR. Slight chance SHRA. Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHRA. Wednesday: Mainly MVFR, with local IFR possible. Likely SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Haynes NEAR TERM...Chai/Haynes SHORT TERM...Boyd LONG TERM...Boyd AVIATION...Myskowski