Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 191852 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 252 PM EDT Wed Jul 19 2017 .SYNOPSIS... A ridge of high pressure will bring warmer and drier conditions to the area today with temperatures in the 80s. A weak cold front approaches late this afternoon in northern New York and evening in Vermont with isolated showers and thunderstorms. Another weak frontal system will bring a slight chance of showers or thunderstorms Thursday and Friday. A little bit cooler and drier weather are likely by Saturday into the first part of Sunday under high pressure from Canada. The next weather system will move in with a chance of showers and thunderstorms later Sunday. && .NEAR TERM /THROUGH THURSDAY NIGHT/... As of 643 AM EDT Wednesday...Overall forecast in good shape with no significant changes needed at this point. Still dealing with areas of low clouds of fog...especially in the favored river and valley locations. Fog and low clouds should dissipate by mid-morning...which going forecast has covered well. Only real tweak was to address band of mid level clouds over the eastern Great Lakes that are moving eastward into the area. Starting to see a trend in these clouds decreasing in areal coverage...but they should have some impact on the area this morning before moving east of the area or dissipating. Rest of forecast in real good shape and no other changes needed at this time. Previous Discussion... Today mostly sunny skies will prevail much of the day and with 850 temps reach 15-16C for high temperatures well into the 80s perhaps touching 87-88 at KBTV. though late afternoon instability increases to 500-1000 J/kg and 0-6km shear around 30 kts in the St. Lawrence valley ahead of a weak cold front. There is also a PW plume of 1.50" ahead of the front which will lead to some increase in mid and high level cloud cover. Low level moisture and dynamics are limited but expected a few showers and thunderstorm to approach KMSS 21-23Z and move southeast possibly reaching KBTV 01-03z but would be isolated at best as daytime heating is gone. Tonight will become partly cloudy with patchy river valley fog possible again though a bit uncertain as the low level flow turns NW and we get some weak cold advection at 850 mb as the weak front drops south of the region. Thursday will be mainly dry though an approaching upper level trof will bring more clouds and perhaps a sprinkle/shower/isld thunderstorm later in the day with warm advection returning. Some very limited instability is forecast with CAPE 250-500 J/kg but PoPs are low as well. The best instability is forecast to remain well south and west of our area. 850 temps a tad lower 13-14C and with more clouds around it will be a few degrees cooler than today. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... As of 229 PM EDT Wednesday...High pressure will be building into the region as west to northwest flow develops aloft. Drying air should lead to some breaks in the clouds during the day which will lead to temps warming into the mid 80s for the valley locations and around 80 in the Northeast Kingdom and Adirondacks. With dry air all around I anticipate mostly quiet weather so I`ve opted to drop even the slight chance wording. Its possible we could see a stray mountain shower but nothing of any impact. In the evening hours we should still be under warm air advection and so our evening lows will continue to be slightly above normal with temps falling to the mid to low 60s. Saturday looks to be a wonderful summer North Country day as high pressure crests just to our northwest. We should see some scattered cloud cover but the sensible weather will be quiet. The cloud cover should be enough to keep temps just on the cooler side with highs in the 70s to near 80. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... As of 229 PM EDT Wednesday...As we end the weekend the flow aloft will transition from northwesterly to more southerly ahead of an advancing low pressure system. We will see clouds increase as a surface boundary with that low pressure system lifts to the north. Moisture advection increases quickly and the chance for showers increase Sunday into Monday. PWATs increase to 1.5 to 1.6 inches but not enough to be overly concerned. Showers will move through with the best chance on Monday morning. The best forcing is to our south but there are enough dynamics to support the idea of a rumble of thunder Sunday night through Monday morning. The upper level trough will swing through late Monday into Tuesday and so chances for shower will continue until the surface front clears the North Country Tuesday afternoon. With the persistent cloud cover and continued chances for rain, our day time temps will be slightly below normal through the early portion of the workweek while our overnight lows should be around normal. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... Through 12Z Thursday...Low clouds and fog at KSLK and KMPV will be eroding through 14z and then all sites will be VFR after 14z. Satellite imagery shows band of mid level clouds just to our west and these clouds will move east across the area through the morning hours...but VFR conditions will still exist. A front will move down toward the Canadian border late in the day and there may be some showers or storms between 22z and 04z at KMSS...KSLK...KPBG...and KBTV. Have mentioned vicinity showers for now but the best chance for a thunderstorm would likely be KMSS. After 04z quiet weather is expected with fog developing once again over parts of the area. LIFR to VLIFR conditions are expected at KPBG...KSLK...and KMPV after 06z with VFR conditions elsewhere. Light winds early this morning...then southwest this afternoon and evening at 10 knots or less...before becoming light and variable once again after 04z. Outlook... Thursday: VFR. Slight Chance SHRA. Thursday Night: VFR. NO SIG WX. Friday: VFR. NO SIG WX. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. Saturday Night: VFR. Slight Chance SHRA. Sunday: VFR. Chance SHRA...Slight Chance TSRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Sisson NEAR TERM...Evenson/Sisson SHORT TERM...Deal LONG TERM...Deal AVIATION...Evenson/Sisson is the U.S. government's official web portal to all federal, state and local government web resources and services.