Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 171425 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 1025 AM EDT Thu Aug 17 2017 .SYNOPSIS... High pressure over the area today will bring dry weather to the area with high temperatures in the 70s to around 80. A warm front will approach the region later tonight from the southwest and enhance the potential for showers and a few thunderstorms across the area...especially over northern New York. Showers and a few thunderstorms will exist over the entire area from time to time...with the potential for some stronger storms over northern New York late in the day on Friday. Showers and storms will taper off Friday night...but scattered showers will exist over the area on Saturday. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... As of 1017 AM EDT Thursday...Fog has burned off as predicted, with filtered sun through thin cirrus providing mostly sunny conditions. Temperatures warming nicely and only minor changes to hourly grids to reflect current conditions. Latest data has 925 mb and 850 mb temperatures supporting afternoon highs in the low 70s mountains and upper 70s in St. Lawrence, Champlain, and southern Connecticut River valleys this afternoon as previously forecast. 500 mb ridging passes across the region today in overall westerly upper level flow. Upper level low moving across the great lakes to the west is spilling some cirrus over the ridge. Surface ridge remains in place for today to provide light wind and dry conditions. For tonight...a well defined warm front will move into the region from the southwest and enhance the threat of showers and embedded thunderstorms across northern New York after midnight. Sharp dew point gradient clearly defines the front and with noticeable warm air advection at 850 mb...showers should be likely with the front. Sharp gradient of Showalter Index values moves into northern New York after midnight and this will enhance the potential for elevated convection. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/... As of 503 AM EDT Thursday...Showers and a few thunderstorms will be ongoing across much of the area Friday morning as warm front lifts northeast across the region. Areal coverage of the showers should decrease around midday as warm front lifts north of the border. Composite analysis shows northern New York getting into the warm sector and instability should develop with highs in the 70s and dew points in the 65 to 70 degree range. At the same time deep layer shear will be increasing over the top of the instability and would expect the potential for thunderstorms to develop in advance of the approaching cold front. Will have to keep an eye on this situation because if sufficient instability develops storms may get organized enough to produce gusty winds...hail...and heavy downpours. Mid level lapse rates are not impressive and thus will need surface heating to help drive the development of instability. Best instability may be across central and southeast New York where shear is a bit weaker. Precipitable water values in this area will be around 2 inches as well. Clouds and showers over Vermont on Friday will keep highs in the upper 60s to mid 70s...but over northern New York highs will be in the 70s to around 80. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 503 AM EDT Thursday...Mainly dry weather is expected from Saturday night through Tuesday morning. Cold air advection continues Saturday night behind departing surface cold front that crossed the area Friday night. Ridge of surface high pressure centered over Ohio river valley will build into our region and remain through early Tuesday. An upper level trough will push across our forecast area Saturday night and Sunday. Looks like good eclipse viewing weather for Monday afternoon. Southwest flow will develop Tuesday as surface ridge moves East of the region, this flow will also advect some much warmer air into the North Country. A low pressure system will pass from the Northern Great Lakes area on Tuesday Northeastward into Central Quebec on Wednesday. Best chance for rain showers will be Tuesday night into Wednesday with surface cold frontal passage. Upper level trough will lag behind a bit, crossing our area Thursday night into Friday. Overall the work week looks unsettled. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... Through 12Z Friday...Overall looking at VFR conditions through much of the period. However...after 04z conditions will trend toward the MVFR category as a warm front moves into northern New York. Showers will increase in areal coverage over northern New York and the potential for some thunderstorms will also exist to help lower ceilings and visibilities. The Champlain Valley may see some showers and storms right toward the end of the period along with the trend to MVFR conditions. Winds will generally be under 10 knots through about 06z...then increase from the southeast during the remainder of the period. Outlook... Friday: VFR/MVFR. Likely SHRA...Slight Chance TSRA. Friday Night: VFR. Likely SHRA...Slight Chance TSRA. Saturday: VFR. Chance SHRA...Slight Chance TSRA. Saturday Night: VFR. Slight Chance SHRA. Sunday: VFR. Slight Chance SHRA. Sunday Night: VFR. NO SIG WX. Monday: VFR. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Evenson NEAR TERM...Evenson/Hanson SHORT TERM...Evenson LONG TERM...Neiles AVIATION...Evenson is the U.S. government's official web portal to all federal, state and local government web resources and services.