Area Forecast Discussion
Issued by NWS Burlington, VT
Issued by NWS Burlington, VT
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199 FXUS61 KBTV 251354 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 954 AM EDT Wed Sep 25 2024 .SYNOPSIS... Early morning showers will wind down toward this afternoon, but then more widespread precipitation will spread over the region tonight and Thursday. Total rainfall amounts of 1 to 2 inches are expected. Drier weather returns for the weekend, along with seasonable temperatures. && .NEAR TERM /THROUGH THURSDAY/... As of 949 AM EDT Wednesday...The current forecast remains in good shape, with only a few minor tweaks needed to temperatures with this update. The main shower activity has continued to push eastward, with eastern Vermont currently seeing a bulk of the showers, although some scattered activity can be seen across most of the forecast area. Overcast skies blanket the region and temperatures continue to be cool, with most places sitting in the upper 40s and 50s this morning. Previous discussion...Overall scope of the forecast remains unchanged, with some much welcome rainfall to occur across the region through the period. We have increased the total rainfall forecast a decent amount with this package, as we`re now that we`re within the realm of hi-res guidance. Noted that ensemble guidance is indicating at least an 85% probability of exceeding 1 inch in most locations over the next 36- 48 hours. However, flooding is still not a concern, especially given how dry we`ve been recently. Our first round of showers is pushing east-northeast across mainly northern/central portions of the forecast area early this morning, with precipitation amounts generally a quarter of an inch or less so far. This scattered shower activity will exit to our northeast by mid morning, and expect we`ll see a brief dry period for a few hours thereafter. Skies will remain cloudy though, and temperatures will be on the cool side as a result. Highs will range from the upper 50s to mid 60s this afternoon. The break in the precipitation will also allow for some mixing, and expect winds will be a little on the breezy side as a result. Gusts around 25 mph will be possible, especially on the northern slopes of the Adirondacks and in the Champlain Valley. After this afternoon`s brief stint of mostly shower-free conditions, expect precipitation to redevelop later this evening and overnight. The upper trough currently crossing into central Ontario will dig into the eastern Great Lakes overnight, closing off into low pressure which will then scoot along the international border on Thursday. Favorable lift and jet dynamics and increasing moisture will allow widespread showers to move northeastward into our area starting this evening but especially overnight. Meanwhile, the upper trough will pivot eastward across Ontario, dragging a frontal boundary along in its wake. This feature will serve as a focus for moisture convergence as it moves eastward across our area Thursday. With PWATs approaching/exceeding 1.5 inches and warm cloud depths of 10-12 kft, briefly heavy rainfall will be possible, and several of the latest hi-res CAMs are indicating a broken line of more robust showers along/ahead of the frontal boundary. Drier air quickly moves in after the frontal passage, bringing widespread precipitation to an end. Scattered showers may redevelop behind the front though as the core of the upper low moves by just to our north. The cold pool associated with the low will steepen lapse rates and allow for a bit of instability, so there may be a few rumbles of thunder along the international border. All in all, expect 1 to 2 inches of rain to fall across the region, with locally higher amounts possible in areas that perhaps see repeated rounds of heavier showers. While some ponding in poor drainage areas may be possible in heavier rainfall rates, the antecedent dry weather and low river flows keep the threat of any flooding low to none. Otherwise, we could still see some breezy conditions overnight tonight, though widespread rainfall will limit mixing potential. At the least though, winds will remain gusty over Lake Champlain, and a Lake Wind Advisory will likely be needed later today and overnight tonight. Winds will abate during the day on Thursday, turning more toward the west/southwest once the front moves through. Ample moisture and cloud cover will keep lows in the 50s areawide tonight. Tomorrow should be warmer than today from the Champlain Valley westward where some sun may make an appearance behind the front, but eastern VT will likely see another day with highs in the upper 50s/low 60s. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/... As of 341 AM EDT Wednesday...The cold front should have passed to the southeast by the start of this period, but some associated rain is possible for a few hours in southern and eastern areas Thursday night. Lingering moisture in the low-levels and northwest flow could cause a few isolated showers across the higher elevations of northern Vermont during the day on Friday. They would be most likely to occur in the afternoon when there is also the influence of diurnal heating. However, any shower would be brief and relatively unimpactful. Low clouds look to hold stubborn in many areas in a more winter-type pattern, though there should be some breaks of sun as well. Highs will be in the mid-60s to low 70s, slightly above climatological normals despite the cloud cover and northwest flow. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 341 AM EDT Wednesday...Surface high pressure builds into the region for the weekend and into the start of next week. The airmass will originate from the central/western US so any of the coldest air will remain well to the north over Canada. Temperatures will continue to be a bit above climatological normals, with highs generally in the upper 60s to mid 70s, and lows generally in the upper 40s to mid 50s. Fog formation is possible in the climatological favored valleys overnight as there should be light boundary layer winds. The one area of uncertainty for fog is cloud cover. The low-level moisture from Friday looks to linger into Saturday and may inhibit fog formation in the areas that remain cloudy. Also, some high clouds look to try to build into the region from the remnants of Helene. However, these currently look to struggle to make it, and anything that does would be very high and thin, and therefore not likely to have a significant impact on radiational cooling. The next chance of rain is in the middle of next week as a cold front passes through. The front will try to bring some of the moisture from the remnants of Helene north and into the region, but even if it does, the rainfall still should be relatively light and not enough produce a flood threat. Less than 20 percent of EC/GFS/Canadian ensemble members have more than 1 inch in 24 hours and none have more than 2 inches. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... Through 12Z Thursday...A mix of VFR and MVFR is expected through the first half of the TAF period, with all terminals trending toward MVFR by 00z Thu. Area of showers is currently pushing eastward across VT, with ceilings generally AOA 4000 ft and visibility occasionally reduced to 3-5SM. This exits by 15z, with isolated showers and ceilings 2500-4000 ft thereafter. More widespread precipitation moves in from southwest to northeast after 22z today and continues through the remainder of the TAF period; expect MVFR ceilings and visibilities to prevail as this rain affects the terminals. IFR possible, especially at KSLK/KMPV. Winds will generally south/southeast between 6-12 kt throughout the TAF period, with some gusts around of 15 to 20 kt possible after 14z. LLWS expected n at all northern NY terminals from 04z onward as a low level jet moves through the region. Outlook... Thursday: MVFR/IFR conditions possible. Chance SHRA, Slight chance TSRA. Thursday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA. Friday: Mainly VFR, with local IFR possible. NO SIG WX. Friday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Saturday: Mainly VFR, with local MVFR possible. NO SIG WX. Saturday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Sunday: Mainly VFR, with local MVFR possible. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Hastings NEAR TERM...Hastings/Kremer SHORT TERM...Myskowski LONG TERM...Myskowski AVIATION...Hastings