Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 251311 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 911 AM EDT Tue Apr 25 2017 .SYNOPSIS... Clouds and moisture from a low pressure area along the mid Atlantic coast will move north into the region today, with rain showers developing across the North Country this afternoon and tonight. Rain showers will continue tonight and into Wednesday. Expecting partly to mostly cloudy skies Wednesday night. Thursday will see warmer temperatures with highs in the 70s under partly sunny skies. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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As of 905 AM EDT Tuesday...quick update based on satellite, radar and surface observation trends. band of rain, most of it on the light side, is pushing northward at a steady pace and on the doorstep of Rutland and Windsor counties. HRRR has a pretty good handle on the current situation, with some of the other hi- res models not too different as well, so relied on that for updating the precipitation movement the next 12 hours or so. Looking at a steady progression northward, with the rain reaching the US/Canada border early this afternoon. With a relatively dry airmass in place, the rain won`t be heavy, looking at mainly rainfall totals <0.15" or so. Expecting less across the Champlain Valley as strengthening southeast winds will lead to downslope shadowing and lesser amounts. However, some enhancement is expected on the eastern slopes of the central/southern Greens, so local totals around 1/4" are possible. Those southeast winds do strengthen as the day goes on, with the NAM indicating about 40kts between 925mb-850mb (roughly 2000-4500ft). As a result, we should see some gusty downslope winds develop along the immediate western slopes of the Green Mountains. However, the expected rainfall should keep the lowest part of the boundary layer stabilized enough that the strongest of winds won`t make it to the surface. Still looking at probably gusts on the order of 25-35 mph. Models do show a break in the precipitation late today/this evening, with a another round of deeper moisture moving in overnight. Noted that showalter values decrease associated with some instability aloft at that time, so expecting the character of the precipitation to turn more showery overnight.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... As of 418 AM EDT Tuesday...Expecting rain showers to continue into Wednesday morning as the closed upper low and the surface low will be coincident with each other south of Long Island New York Wednesday morning. This low will then move east and be over Cape Cod Wednesday night. Expecting the North country to be partly to mostly cloudy Wednesday night, but remaining dry. Models showing upper ridge to build into the region by late Wednesday night. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 420 AM EDT Tuesday...Not much change in the forecast but overall active period during the long term. The period will start off dry as rain showers associated with coastal low continue to move east. Some lingering clouds may limit warming over eastern Vermont, but generally expect temperatures in the 70s. Thursday night into Friday will have chance for showers and possible thunderstorms that are expected to move west to east across the North Country as a long wave 500mb trough becomes negatively titled over Ontario, extending into the eastern Great Lakes. Reflected at the surface, a front boundary will provide the lift for these showers...clearing the area by Friday night. Heading into the weekend, a Bermuda high looks to develop at the surface and aloft. Several areas of vorticity at 500mb will move from SW towards southern Quebec and possibly impact the North Country through Saturday night. On Sunday, Canadian high pressure centered around James Bay will retreat north and east as strengthening closed surface low moves northward from Texas towards the western Great Lakes by late Sunday. A warm front ahead of the low looks to bring more showers by Sunday night. GFS and ECMWF still show differences on evolution and track of this system, but strong low level jet associated with cold front will create good moisture plume from the Gulf of Mexico northward. Expect this cold front to move into the North Country sometime Monday. Overall expect this system to be capable of producing heavy rainfall and strong winds from tight pressure gradient and strengthening of low. Also, thunderstorm activity expected ahead and along the cold front as GFS indicates 500-1000 J/kg in the St Lawrence Valley and negative lifted indices. && .AVIATION /13Z TUESDAY THROUGH SATURDAY/... Through 12Z Wednesday...Mainly VFR conditions expected through 00Z Wednesday. Satellite loop and surface observations showing mainly high and mid clouds across the region at this time. Expecting ceilings to slowly lower through the day. Bufkit forecast soundings showing fairly dry conditions across the region, so it will likely take a while to saturate the lower levels of the atmosphere. Expecting any rain shower activity will likely not reach the surface until this afternoon or this evening. Expecting mainly MVFR conditions in rain showers after 00Z Wednesday. Outlook... Wednesday: VFR/MVFR. Chance SHRA. Wednesday Night: VFR. Slight Chance SHRA. Thursday: VFR. NO SIG WX. Thursday Night: VFR. Slight Chance SHRA...TSRA. Friday: VFR. Chance SHRA...TSRA. Friday Night: VFR. Chance SHRA. Saturday: VFR. Chance SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...WGH NEAR TERM...Nash SHORT TERM...WGH LONG TERM...KGM AVIATION...WGH/SLW is the U.S. government's official web portal to all federal, state and local government web resources and services.