Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 030233 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1033 PM EDT WED SEP 2 2015 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE AND WEAK SURFACE COLD FRONT WILL MOVE INTO THE NORTH COUNTRY FROM QUEBEC AND ONTARIO TONIGHT. THIS SYSTEM WILL BRING A PERIOD OF MOSTLY CLOUDY CONDITIONS OVERNIGHT INTO THURSDAY MORNING...ALONG WITH A FEW RAIN SHOWERS AND ISOLATED THUNDERSTORMS. SHOWERS AND ISOLATED THUNDERSTORMS WILL INCREASE IN COVERAGE ACROSS SOUTH-CENTRAL VERMONT BEFORE EXITING TO OUR SOUTH DURING EARLY THURSDAY AFTERNOON. THEREAFTER...A DEEP LAYER RIDGE WILL RETURN TO THE REGION. TEMPERATURES WILL BE CLOSER TO SEASONAL AVERAGES ON FRIDAY WITH LOWER HUMIDITY...BUT THE OVERALL TREND WILL BE TOWARD VERY WARM...MODERATELY HUMID...AND MAINLY CLEAR CONDITIONS FOR THE HOLIDAY WEEKEND. && .NEAR TERM /UNTIL 11 AM THURSDAY MORNING/... AS OF 1023 PM EDT WEDNESDAY...SHOWERS HAVE CONTINUED TO STRUGGLE TO CROSS THE SAINT LAWRENCE VALLEY SO I TRENDED BACK THE FORECAST JUST A BIT. OTHERWISE THE CURRENT FORECAST IS IN GOOD SHAPE WITH SOME LIGHT FOG DEVELOPING IN NORTHERN NEW YORK. WITH LIGHT CIRRUS IS MOVING IN AHEAD OF THE FRONT I EXPECT IT WILL TEMPER HOW DENSE THE FOG GETS AS WE LIKELY WONT CLEAR OUT ENOUGH AHEAD OF THE FRONT TO BOTTOM OUT COMPLETE. TEMPS AND DEW POINTS ARE IN GOOD SHAPE MOVING FORWARD WITH NO ADDITIONAL CHANGES NEEDED. PREVIOUS DISCUSSION AS OF 613 PM EDT WEDNESDAY... SHOWERS ASSOCIATED WITH A PREFRONTAL TROUGH ARE SLOWLY MOVING TOWARDS THE ESE JUST TO THE NORTH AND WEST OF OTTAWA. BASED ON LATEST LAPS ANALYSIS THE AREA STILL IS QUITE PRIMED FOR INSTABILITY AS THE RIDGE BRIEFING BREAKS DOWN THIS EVENING. THE FRONT IS STILL WELL WEST OF THE FORECAST REGION AND ISN`T EXPECTED UNTIL MUCH LATER THIS EVENING. THE CURRENT FORECAST HAS THESE SHOWERS COVERED WITH MENTION OF SCATTERED SHOWERS WITH ISOLATED THUNDERSTORMS ACROSS NORTHERN NEW YORK AND THE VERMONT CANADA BORDER. EXPECT AS THE SHOWERS FINALLY BEGIN TO MOVE INTO THE NORTH COUNTRY THAT THE LOSS OF DIURNAL HEATING WILL DECREASE OUR OVERALL CHANCES FOR SHOWERS AND SO ISOLATED SHOWERS CAN BE EXPECTED IN THE LATE OVERNIGHT HOURS. TEMPS AND DEWPOINTS ARE IN GOOD SHAPE WITH NO CHANGES NEEDED. PREVIOUS DISCUSSION AS OF 331 PM EDT WEDNESDAY...VERY WARM AFTERNOON IN PROGRESS ACROSS THE NORTH COUNTRY WITH HIGH TEMPERATURES GENERALLY REACHING THE MID TO UPPER 80S. SKIES ARE MOSTLY CLEAR...AND SHOULD REMAIN SO THRU THE EARLY EVENING HOURS WITH JUST SOME PASSING CIRRUS CLOUDS...A FEW FAIR WEATHER CUMULUS CLOUDS...AND A BIT OF HAZE WITH DEWPOINTS IN THE MID-UPR 60S IN MOST LOCATIONS. SLIGHTLY HIGHER DEWPOINTS ARE PRESENT IN THE ST. LAWRENCE VALLEY...ALONG WITH SOME LINGERING AREAS OF STRATUS CLOUDS TRAPPED BENEATH RELATIVELY LOW SUBSIDENCE INVERSION BASE (AROUND 850MB). WINDS GENERALLY LIGHT AND VARIABLE THROUGH THIS EVENING. VISIBLE SATELLITE IMAGERY REVEALS APPROACHING WEAK COLD FRONT AND DEVELOPING SHOWERS/THUNDERSTORMS ACROSS SWRN QUEBEC...WELL NORTH AND WEST OF MONTREAL. AS UPR RIDGE BRIEFLY WEAKENS OVERNIGHT...ASSOCIATED SHORTWAVE TROUGH AND FRONTAL BNDRY WILL SHIFT SWD REACHING THE ST. LAWRENCE VALLEY TOWARD MIDNIGHT...AND SHIFTING ACROSS NRN VT DURING THE EARLY MORNING HOURS THURSDAY. PASSAGE OF THE BNDRY AND UPPER LEVEL SHORTWAVE IS OCCURRING DURING DIURNAL MINIMUM IN CONVECTIVE INSTABILITY. AS SUCH...MOST OF THE SHOWER/ISOLD THUNDERSTORM ACTIVITY WILL DISSIPATE...AND CARRIED JUST A 20-30 POP OVERNIGHT ACROSS NRN NY INTO FAR NRN VT ASSOCIATED WITH THIS FEATURE. WILL SEE AN INCREASE IN CLOUD COVER...WHICH WILL HELP KEEP OVERNIGHT LOWS QUITE MILD...MAINLY IN THE LOW-MID 60S...WITH A FEW UPPER 50S IN THE NRN ADIRONDACKS AND FAR NERN VT. ARRIVAL OF ANY SIGNIFICANT CLOUD COVER WITH THE FRONT MAY BE LATE ENOUGH TO ALLOW PATCHY FOG FORMATION EAST OF THE GREEN MTNS. LIMITED PATCHY FOG IN THE FORECAST TO THOSE FAVORED AREAS ACROSS CENTRAL AND EASTERN VT. NW-N WIND SHIFT AND MID-LEVEL VORT GRADUALLY PUSH SWD ACROSS VT DURING THE DAYLIGHT HRS THURSDAY. WITH DAYTIME HEATING...WILL LIKELY SEE AN EXPANSION IN THE COVERAGE OF SHOWERS AND A FEW THUNDERSTORMS AS FRONTAL CONVERGENCE REACHES S-CENTRAL VT...AND ULTIMATELY EXITS OUR FORECAST AREA DURING THE AFTERNOON HOURS. HAVE INDICATED AREAS OF 30-40 POPS ACROSS S-CENTRAL VT DURING THE MID-DAY PERIOD THURSDAY BEFORE FRONT EXITS. BEHIND THE FRONT...WILL SEE A SLIGHTLY COOLER AIR MASS WITH NORTHERLY WINDS AROUND 10 MPH FOR THE AFTN HRS...ALONG WITH CLEARING CONDITIONS BY EARLY AFTN. STRONG DROP IN PW VALUES LATE IN THE DAY AS WELL WILL BE COINCIDENT WITH BOUNDARY LAYER DEWPOINTS FALLING INTO THE UPR 50S NORTH AND LOWER 60S SOUTH. HIGH TEMPERATURES SEVERAL DEGREES COOLER THAN ANTICIPATED HIGHS WEDNESDAY...WITH THURSDAY SEEING 80-85F MOST SECTIONS. && .SHORT TERM /11 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... AS OF 331 PM EDT WEDNESDAY...DEEP-LAYER RIDGE BECOMES REESTABLISHED ACROSS THE NORTH COUNTRY WITH NIL POPS. VERY QUIET PERIOD...WITH POTENTIAL FOR SOME NOCTURNAL FOG 06-12Z BOTH THURSDAY NIGHT AND AGAIN FRIDAY NIGHT...UNDER MAINLY CLEAR CONDITIONS. DAYLIGHT HRS FRIDAY SHOULD BE QUITE PLEASANT...WITH HIGHS UPPER 70S TO LOWER 80S UNDER MOSTLY SUNNY SKIES...AND DEWPOINTS BACK INTO THE LOWER 50S. LOW TEMPS MAINLY IN THE 50S BOTH THURSDAY AND FRIDAY NIGHTS...BUT A FEW MID-UPR 40S IN THE NORMALLY COOLER SPOTS OF VERMONT/S NORTHEAST KINGDOM AND WITHIN THE VALLEYS OF THE NRN ADIRONDACKS. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 235 PM EDT WEDNESDAY...VERY WARM AND MOSTLY SUNNY CONDITIONS EXPECTED ONCE AGAIN THIS WEEKEND AND INTO NEXT WEEK. UPPER LEVEL RIDGE PARKED OVERHEAD SATURDAY-SUNDAY WILL LEAD TO MOSTLY SUNNY SKIES AND WELL ABOVE NORMAL TEMPERATURES. HIGHS FORECAST 80-85 SATURDAY...INCREASING TO 83-88 ON SUNDAY WITH LOWS GENERALLY UPPER 50S TO MID 60S. SOME FOG DEVELOPMENT ALSO LIKELY IN THE OVERNIGHT/EARLY MORNING HOURS IN THE FAVORED RIVER VALLEYS. THE RIDGE WILL BEGIN TO SLIDE SOUTHWARD MONDAY-WEDNESDAY OF NEXT WEEK ALLOWING FOR SOME WESTERLY FLOW TO RETURN TO THE REGION...WITH A POSSIBLE WEAK SYSTEM BRINGING THE CHANCE OF A FEW SHOWERS/THUNDERSTORMS ON TUESDAY. HOWEVER PARTLY-MOSTLY SUNNY SKIES AND VERY WARM TEMPERATURES WILL PERSIST. HOTTEST TEMPERATURES LIKELY MONDAY WITH WIDESPREAD 85-90 DEGREE TEMPERATURES (15-18 DEGREES ABOVE NORMAL). TUESDAY MAY BE A COUPLE OF DEGREES COOLER WITH INCREASED CLOUD COVER AND CHANCES FOR SHOWERS. WARMTH PERSISTS INTO WEDNESDAY AHEAD OF A POSSIBLE STRONGER SYSTEM LATE WEEK WITH HIGHS STILL 80-85. LOWS UPPER 50S TO MID 60S THROUGH THE PERIOD. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... THROUGH 00Z THURSDAY...THIS WAS A TOUGH FORECAST GIVEN THE UNUSUALLY WARM AND MOIST PATTERN WE ARE IN. SOME SHOWERS ARE AHEAD OF A PREFRONTAL TROUGH AND ARE SLOWLY ADVANCING TOWARDS THE SAINT LAWRENCE VALLEY SO I DID GO AHEAD AND INCLUDE VCSH FOR BOTH SLK/MSS. JUST OUT AHEAD OF THE SHOWERS THERE IS QUITE A BUT OF HAZE THAT HAS ALREADY BROUGHT BOTH MSS AND SLK TO MVFR VISIBILITIES. OVERNIGHT AS THE FRONT MOVES CLOSER TO THE AREA EXPECT INCREASING CLOUDS ALOFT AND NEAR THE SURFACE. UPSTREAM OBS HAVE SHOWN SOME IFR CEILINGS IN THE 400-800FT RANGE AS THE FRONT MOVES THROUGH BUT I DONT HAVE QUITE THE CONFIDENCE IN THOSE CEILINGS. I DID BRING DOWN MOST SITES TOMORROW AS THE FRONT CROSSES THE FORECAST AREA TO MVFR 2000-3000FT. FOG/BR IS TOUGH RIGHT NOW BECAUSE AS THE FRONT MOVES IN CLOSER THE CLOUDS WILL HINDER DEVELOPMENT BUT WITH THE WARM MOIST AIRMASS WE MAY NOT NEED TEMPS TO DROP BELOW CROSSOVER TO DEVELOP SOME BR/HZ AT MSS/SLK/MPV. I DID INCLUDE IFR VISIBILITY AS A TEMPO GROUP IN AT BOTH MPV/SLK AND CONTINUED MVFR AT MSS. THE WEAK FRONT WILL MOVE THROUGH OVERNIGHT DRYING OUT THE AREA BUT NOT BY VERY MUCH AND A WIND SHIFT FROM VARIABLE LIGHT SOUTHERLY TO OUT OF THE NORTH TOMORROW ISN`T EXPECTED UNTIL LATE MORNING. THERE WILL STILL BE SOME LINGERING MOISTURE AROUND TOMORROW SO AS WE PICK UP DIURNAL HEATING IN THE MORNING THE FRONT COULD REINVIGORATE AND DEVELOP SCATTERED TO ISOLATED SHOWERS AND THUNDERSTORMS MAINLY ACROSS CENTRAL AND SOUTHERN VERMONT. GIVEN TIMING STUCK WITH JUST MENTION OF VCSH TOMORROW MAINLY THROUGH 14-21Z. OUTLOOK 00Z THURSDAY THROUGH MONDAY... MAINLY VFR. EARLY MORNING VLIFR/IFR CEILINGS AND VISIBILITIES LIKELY AT MPV/SLK, AND POSSIBLE AT MSS. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...BANACOS NEAR TERM...BANACOS/DEAL SHORT TERM...BANACOS LONG TERM...MUCCILLI AVIATION...DEAL

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