Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 210758 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 358 AM EDT Fri Jul 21 2017 .SYNOPSIS...
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A sunny start is expected for the North Country today...but the threat of some showers or storms will exist this afternoon... especially over northeast New York and the northern third of Vermont. Any showers or storms will have the potential to produce gusty winds before coming to an end this evening. A dry day is expected for Saturday. Eventually we will transition to a wetter pattern Sunday into Monday. Expect one more day of above normal temperatures today...then a transition to at or below normal temperatures for the weekend and early next week.
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&& .NEAR TERM /THROUGH SATURDAY/...
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As of 358 AM EDT Friday...Clear skies and light winds over the area early this morning has led to the development of fog over central and eastern Vermont. Fog not as prevalent as this time yesterday given slightly drier low levels and some stronger winds in the low level to promote a bit of mixing. This fog should burn off by mid-morning. Should see a good deal of sun through midday before trough moves across eastern Canada and helps to move a front down into our area. This should enhance the potential for some showers and storms this afternoon...although areal coverage should be isolated in nature. It looks like northeast New York and the northern third of Vermont will have the best chance of seeing these isolated showers or storms. Instability is not strong but it is sufficient for thunder potential. Deep layer shear will also be increasing as the afternoon wears on and the drier low levels mentioned earlier indicate some increased downdraft potential. Have included the mention of gusty winds with any of the storms over the northern third of Vermont where forecast soundings support this idea. High temperatures today will be in the upper 70s to mid 80s. The mid 80s will be most common on the Vermont side of the Champlain Valley as downsloping westerly winds will help warm the temperatures more than other areas. Any convection ends this evening and quiet weather is expected for the overnight hours. Much of Saturday should remain dry too with west to northwest flow aloft over the area. Highs will be a few degrees cooler than Friday with readings in the mid 70s to lower 80s. Cannot rule out the possibility of some showers moving in late in the day on Saturday over parts of northern New York and the southern half of Vermont...but the bulk of the precipitation should remain south of our area.
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&& .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
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As of 358 AM EDT Friday...Trend in the latest NWP guidance for the latter half of the weekend is trending drier, though I will note that could easily change. The forecast largely depends on how low pressure evolves out of convection expected to fire up over the Wisconsin/Minnesota area this afternoon and night, and where the mid-level thermal packing sets up downstream. There`s a general consensus that the boundary will set up south of the BTV forecast area, with a comparison of the 00Z NAM/ECMWF/GFS showing the GFS as the outlier with the most northern track and deeper low. Don`t want to totally discount it, so I`ve offered a blended forecast for PoPs, trending towards the drier NAM/ECMWF. This results in low chance PoPs across our southern zones Saturday night, with only a slight chance north. Anything that does affect the area overnight will dissipate by Sunday morning with a mainly dry day expected, though chances for more widespread showers increases from the southwest in the afternoon as our next system approaches.
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&& .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
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As of 358 AM EDT Friday...Sunday night through Tuesday continues to look like the main active period of the next 7 days as medium range guidance is in good agreement highlighting an upper trough digging through the Great Lakes Sunday night and across the Northeast through Tuesday with a series of embedded shortwave troughs bringing periods of precipitation to the North Country. Best dynamical forcing shifts over the CWA Sunday night into Monday morning with a decent plume of PWATs around 1.5" skirting southern areas and modest mid-level lapse rates around 6 C/km supporting the idea of some thunder, but overall convective threat is rather low. Additional showers continue Monday afternoon right through Tuesday as the trough shifts over and east of the region by 00Z Wednesday. By Tuesday night surface high pressure and ridging aloft build into the area with sunny/clear conditions expected for Wednesday and Wednesday night. A weak cold front approaches for Thursday renewing chances for showers along our northern border.
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&& .AVIATION /08Z FRIDAY THROUGH TUESDAY/...
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Through 06Z Saturday...Overall looking at VFR conditions through the period. The only exception will be at KSLK and KMPV where periods of IFR conditions may exist through 12z due to low clouds and fog. Some wind does exist just off the surface and this may limit the areal extent of fog early this morning. A front will move toward the region this afternoon and we will see winds become more west with time at speeds around 10 knots before tapering off after 00z. With the front there may be the potential for some showers/storms over northeast New York and the northern third of Vermont between 18z and 00z...but still looking at VFR conditions as any showers or storms will be isolated in nature. Outlook... Saturday: VFR. NO SIG WX. Saturday Night: VFR. Slight Chance SHRA...Slight Chance TSRA. Sunday: VFR. Chance SHRA...Slight Chance TSRA. Sunday Night: VFR. Chance SHRA...Slight Chance TSRA. Monday: VFR. Chance SHRA...Chance TSRA. Monday Night: VFR/MVFR. Chance SHRA. Tuesday: VFR/MVFR. Chance SHRA.
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&& .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Evenson NEAR TERM...Evenson SHORT TERM...Lahiff LONG TERM...Lahiff AVIATION...Evenson

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