Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 191043 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 643 AM 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/...
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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.
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&& .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/... As of 328 AM EDT Wednesday...West to northwest flow aloft becomes established over the area during the period. Any showers Thursday evening should dissipate before midnight and prospects of convection on Friday are looking a bit limited. Instability is expected to develop...but forcing and deep layer shear are not that strong. Like the idea of slight chance wording at best with respect to any convection Friday afternoon. Above normal temperatures are expected on Friday with highs in the upper 70s to mid 80s. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 328 AM EDT Wednesday...West to northwest flow aloft continues Friday night through Saturday night and thus looking at relatively dry weather. Cooling temperatures aloft on Saturday suggest highs will be in the mid 70s to lower 80s. It looks like the flow aloft transitions to the west on Sunday and eventually the southwest on Monday. This will allow for a boundary to move northeast into our area as well as increasing moisture into the region. As dynamic support increases from an approaching trough...precipitation chances will be increasing Sunday and especially on Monday. Clouds and precipitation Sunday into Monday will allow for temperatures to be at or slightly below seasonal normals. Upper trough moves across the area Monday night into Tuesday and as a result we will still be looking at a chance of showers with slightly below normal temperatures continuing into Tuesday. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... Through 06Z Thursday...VLIFR at KSLK and KMPV 06-12Z and briefly IFR at PBG in patchy fog otherwise mainly VFR through the rest of the day. Some increase in high clouds during the afternoon as upper level moisture moves into the region ahead of a weak cold front. This front may touch off isolated showers and thunderstorms aft 21z at KMSS and if they hold together reaching BTV 01-03z but should be decreasing rapidly by then so just have VCSH in the TAFs for now. Calm winds will become SW at 5-10 knots by midday with perhaps a G17kt at KMSS this afternoon. Winds will decrease after sunset tonight. Outlook... Thursday: VFR. Slight Chance SHRA. Thursday Night: VFR. Slight Chance SHRA. Friday: VFR. Slight Chance SHRA...Slight Chance TSRA. Friday Night: VFR. Chance SHRA...Slight Chance TSRA. Saturday: VFR. Chance SHRA. Saturday Night: VFR. Slight Chance SHRA. Sunday: VFR. Chance SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Sisson NEAR TERM...Evenson/Sisson SHORT TERM...Evenson LONG TERM...Evenson AVIATION...Sisson is the U.S. government's official web portal to all federal, state and local government web resources and services.