Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 151059 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 659 AM EDT Tue Aug 15 2017 .SYNOPSIS...
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Expect increasing chances for showers and thunderstorms across the North Country...especially this afternoon through early evening. Any of the thunderstorms will have the potential to become strong and produce gusty winds...small hail...frequent lightning...and brief heavy downpours. The area that will have the best potential to see these stronger storms will be northeast New York and the northern and central sections of Vermont. An upper level trough of low pressure will be responsible for the increased threat of showers and storms this afternoon and evening...but as this system moves east tonight cooler and drier weather will move in on northwest flow aloft. Dry weather is expected on Thursday as well with slight warmer temperatures than Wednesday. The next chance for more widespread showers will come late Thursday night and especially on Friday.
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&& .NEAR TERM /THROUGH TONIGHT/...
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As of 659 AM EDT Tuesday...Going forecast in good shape with no real big changes needed at this time. Potential still looks good for some stronger storms this afternoon and early evening. Deep layer shear will become sufficiently strong across the area this afternoon and evening as well defined shortwave trough moves out of the eastern Great Lakes and into the Northeast. Models are overdone on the amount of instability that develops this afternoon with dew point forecasts too high. However...a nearly dry adiabatic lapse rate will develop from 850-500 mb later this afternoon and produce a sufficient amount of instability for convection. Thinking CAPE values in the 800-1200 J/kg range are likely over parts of northeast New York and Vermont along and east of a weak surface boundary. Going forecast already has enhanced wording in the forecast and will tweak just a bit to highlight best potential for stronger storms. At this time feel Clinton and Essex counties of New York and in Vermont from Addison and Orange counties northward to the Canadian Border. Gusty winds appear to be the main threat...but small hail will also be possible. Highs today will be in the mid 70s to lower 80s. For tonight...isolated to scattered showers and storms should come to an end around midnight as shortwave trough moves east and dynamic support decreases as a result. Low temperatures will range from the mid 50s to lower 60s...with some lower 50s in the mountains.
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&& .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... As of 415 AM EDT Tuesday...Northwest flow aloft becomes established over the area through much of the period. This will continue to bring dry weather to the region and no precipitation is expected. Cold air advection takes place on Wednesday with highs in the 70s and even some 60s in the mountains. The cooldown will be short lived as warm air advection develop on Thursday highs return to the 70s...with the larger valleys getting close the 80. Lower dew points will make for rather pleasant conditions as indicated by the lows Wednesday night with readings in the mid 40s to mid 50s. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 415 AM EDT Tuesday...Guidance has come in much closer agreement than the past several days and thus has elevated confidence in this period. All models show ridging at all levels keeping things dry on Thursday as eluded to yesterday but even slower with rainfall not til perhaps aft 06z Fri. Surface wave/front slowly moves thru region late Fri- Fri ngt thus wettest being Fri as PWATS approaching 1.5 inches. Prelim storm total pcpn thru 12z Sat is 0.75-1.25 inches. Upper level trof/shortwave not pushing through til Sat ngt-Sun thus still a threat of showers Sat-Sat ngt-Sun. Shower threat largely diurnal in nature...mainly Sat/Sun aftn due to daytime heating/instability. Pcpn amounts Thereafter..ridging at all levels moves in for early next week (Mon) before a cold front pushes through midweek. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/...
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Through 12Z Wednesday...Other than some brief periods of MVFR ceilings through mid-morning most of the morning hours will be VFR. We will see a return to periods of MVFR conditions after 18z through about 02z and chances for showers and storms increase. Any of the thunderstorms will have the potential to produce gusty winds...small hail...frequent lightning...and brief heavy downpours. Otherwise...showers and storms come to an end between 02z and 06z with VFR/MVFR ceilings persisting through the remainder of the period. Winds will turn to the northwest late in the period...but will not become gusty into the daytime hours on Wednesday. Outlook... Wednesday: VFR. NO SIG WX. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. NO SIG WX. Thursday Night: VFR. Slight Chance SHRA. Friday: MVFR. Likely SHRA. Friday Night: VFR/MVFR. Chance SHRA...Slight Chance TSRA. Saturday: VFR/MVFR. Chance SHRA...Slight Chance TSRA.
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&& .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Evenson NEAR TERM...Evenson SHORT TERM...Evenson LONG TERM...SLW AVIATION...Evenson

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