Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 011129 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 729 AM EDT WED JUL 1 2015 .SYNOPSIS... MOSTLY CLOUDY SKIES WITH SCATTERED SHOWERS AND A FEW EMBEDDED THUNDERSTORMS EXPECTED TODAY AS A TROUGH OF LOW PRESSURE LIFTS NORTHEASTWARD ACROSS THE NORTH COUNTRY. A FEW STRONGER THUNDERSTORMS ARE POSSIBLE ACROSS VERMONT THIS AFTERNOON...AND MAY PRODUCE GUSTY WINDS AND HEAVY DOWNPOURS. AS THE LOW PRESSURE AREA DEPARTS NORTHEASTWARD ACROSS CENTRAL QUEBEC TONIGHT...A DRIER AIR MASS WILL MOVE INTO THE NORTH COUNTRY RESULTING IN GENERALLY PLEASANT WEATHER CONDITIONS AND LOW HUMIDITY FOR THURSDAY...FRIDAY...AND INDEPENDENCE DAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 317 AM EDT WEDNESDAY...AMPLIFIED MID-LEVEL TROUGH EXTENDING NORTH-SOUTH FROM SERN ONTARIO ACROSS ERN OH/WV EARLY THIS MORNING WILL ACQUIRE SLIGHT NEGATIVE TILT AS IT TRANSLATES NEWD ACROSS NY LATE THIS MORNING AND ACROSS VERMONT THIS AFTERNOON. MODERATELY STRONG HEIGHT FALLS (BY EARLY JULY STANDARDS)...CYCLONIC FLOW AND MID-LEVEL DIFFERENTIAL VORTICITY ADVECTION WILL ALL CONTRIBUTE TO LARGE-SCALE ASCENT AND SCATTERED TO WIDESPREAD SHOWER ACTIVITY. IT APPEARS SHOWERS WILL BE MOST WIDESPREAD THIS AFTN...BUT PREVAILING MOSTLY CLOUDY CONDITIONS AND COOLING INFLUENCE OF WIDESPREAD SHOWERS MAKE FORECAST MAX SURFACE- BASED INSTABILITY A BIT UNCERTAIN FOR THE AFTERNOON. MOST OF THE NUMERICAL GUIDANCE...INCLUDING NAM12/GFS/LOCALLY RUN BTV-4KM WRF INDICATE SBCAPE VALUES 1000-1500 J/KG ACROSS CENTRAL AND SRN VT AND PORTIONS OF THE CHAMPLAIN VALLEY...WITH GENERALLY 500-1000 J/KG ACROSS NRN NY. SWLY SFC-6KM SHEAR IS GENERALLY 25-30 KTS...SUGGESTING SOME STORM ORGANIZATION IF INSTABILITY CAN MATERIALIZE AS FORECAST. WOULD ANTICIPATE A FEW STRONGER STORMS...MAINLY ACROSS VT...DURING THE AFTERNOON HOURS WITH GUSTY WINDS AND HEAVY DOWNPOURS. CAN/T COMPLETELY RULE OUT A SEVERE STORM OR TWO...WITH BEST POTENTIAL CENTRAL/S-CENTRAL VT...BUT WILL DEPEND ON DEVELOPMENT OF SURFACE BASED INSTABILITY AS BEST MID- LEVEL FORCING MOVES THRU CENTRAL VT THIS AFTERNOON. SPC 21Z CALIBRATED SREF PROBABILITY OF SEVERE STORMS SHOWS SOME LOW POTENTIAL ACROSS VT THIS AFTN (HIGHEST 18-21Z) AND INITIAL 06Z SPC DAY 1 OUTLOOK CARRIES 5% PROBABILITY OF SVR HAIL/WIND WITHIN 25 MILES OF A POINT. WILL CARRY MENTION OF SUB-SEVERE WIND IN THE GRIDS AND WILL CONTINUE TO MONITOR MESOSCALE TRENDS INTO THE DAYLIGHT HRS. HIGHS TODAY GENERALLY EXPECTED IN THE MID-UPR 70S WITH DEWPOINTS IN THE 60-65F RANGE. GRADIENT FLOW SUPPORTS SOUTHERLY WINDS 10-15 MPH ACROSS MOST OF THE AREA LATE THIS MORNING THROUGH MID AFTN BEFORE GRADUALLY DIMINISHING THIS EVENING. GUSTS 25-30 MPH POSSIBLE THIS AFTN. HIGHEST POP VALUES GENERALLY THIS AFTERNOON (70-90%)...AND THEN RAPIDLY DIMINISHING AFTER 00Z AS MID-LEVEL TROUGH AXIS SHIFTS NORTH AND EAST OUT OF THE AREA. WILL SEE A WESTERLY WIND SHIFT WITH A MODEST ACCOMPANYING COLD FRONT PASSING THRU 00-03Z WITH TEMPERATURES DROPPING BACK INTO THE MID 50S FOR MOST AREAS. SHOULD BE ENOUGH LOW- LEVEL FLOW AND LINGERING CLOUDS THRU AT LEAST THE FIRST HALF OF TONIGHT TO LIMIT NOCTURNAL FOG DEVELOPMENT IN MOST AREAS. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... AS OF 317 AM EDT WEDNESDAY...DEEP-LAYER CYCLONE LIFTS OUT NEWD ACROSS QUEBEC BY DAYBREAK THURSDAY. 00Z GFS/NAM MODEL SOUNDINGS INDICATE SUBSTANTIAL LOW TO MID-LEVEL DRYING IN THE WAKE OF THIS SYSTEM IN PREVAILING MODERATELY STRONG WESTERLY FLOW REGIME...AND SHOULD YIELD MOSTLY SUNNY SKIES FOR THE BALANCE OF THE DAY. IT WILL FEEL PLEASANT WITH SURFACE DEWPOINTS FALLING INTO THE MID 40S BY AFTERNOON. DAYTIME MIXING/INSOLATIONAL HEATING WILL RESULT IN WESTERLY SURFACE WINDS OF 8-14 MPH 15-23Z. 850MB TEMPERATURES AROUND +8C AND SUNSHINE SUPPORTS VALLEY HIGH TEMPERATURES GENERALLY IN THE MID 70S. NO PRECIP IS EXPECTED. WEAK SURFACE RIDGE BUILDS INTO THE REGION FROM THE WEST THURSDAY NIGHT AND WILL BE ACCOMPANIED BY 1000-500MB MEAN RH VALUES OF 20-30 PERCENT. ALL IN ALL A QUIET AND MOSTLY CLEAR NIGHT WITH LIGHT AND VARIABLE WINDS CONTROLLED BY LOCAL OROGRAPHIC EFFECTS. WITH MOIST SOIL CONDITIONS...WILL LIKELY SEE SOME PATCHY FOG FORMATION IN THE FAVORED VALLEY LOCATIONS 06-12Z FRIDAY. GOOD RADIATIONAL COOLING WILL RESULT IN WIDE TEMPERATURE RANGE FROM THE MID 40S ACROSS THE NRN ADIRODNACKS AND VERMONT/S NORTHEAST KINGDOM...TO THE LOW-MID 50S IN THE CHAMPLAIN VALLEY (WARMEST NEAR LAKE CHAMPLAIN). CONTINUED PLEASANT WEATHER CONDITIONS FRIDAY/FRIDAY EVENING WITH MAINTENANCE OF WEAK RIDGING SURFACE AND ALOFT AND <30% MEAN 1000-500MB RH VALUES. 850MB TEMPS MODERATE SOME TO +10 TO +12C AND SHOULD SEE VALLEY HIGHS IN THE UPPER 70S...BUT WITH CONTINUED LOW DEWPOINTS IN THE MID-UPR 40S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 340 AM EDT WEDNESDAY...LATEST TRENDS HAVE BEEN FOR GREATER UNCERTAINTY ON CHCS FOR PRECIP ON SATURDAY AND SUNDAY ASSOCIATED WITH WEAK NORTHERN AND SOUTHERN STREAM SYSTEMS. OTHERWISE...EXCELLENT AGREEMENT WITH DEVELOPMENT OF MID/UPPER LVL RIDGE AND SFC HIGH PRES FOR EARLY NEXT WEEK...RESULTING IN ABOVE NORMAL TEMPS AND DRY CONDITIONS FOR MONDAY AND MOST OF TUESDAY. HAVE CONTINUE TO MENTION SCHC TO LOW CHC POPS FOR SATURDAY ASSOCIATED WITH VERY WEAK SFC BOUNDARY AND 5H VORT IN JET WINDS ALOFT. BOTH GFS/ECMWF SHOW WEAK RIBBON OF ENHANCED MID LEVEL MOISTURE IMPACTING OUR NORTHERN ZNS...WITH VERY MINIMAL INSTABILITY VALUES. HAVE JUST MENTION SHOWERS WITH NO THUNDER ATTM. QPF WILL BE VERY LIGHT AND MAINLY CONFINED TO THE NORTHERN MTNS ON SATURDAY. MODELS DISAGREE ON SUNDAY...WITH LATEST 00Z GFS SHOWING SOUTHERN STREAM SYSTEM COMING CLOSE ENOUGH TO PROVIDE OUR REGION WITH LIGHT PRECIP CHCS WHILE ECMWF IS MAINLY DRY. GFS SHOWS BETTER 850 TO 500MB RH FIELDS...ALONG WITH A DEEPER TROF ACROSS THE NORTHEAST CONUS ON SUNDAY...RESULTING IN SOME LIFT AND WEAK INSTABILITY. WILL KEEP FCST DRY...BUT WOULD NOT BE SURPRISED A FEW SHOWERS/SPRINKLES DEVELOP DURING THE AFTERNOON HOURS ON SUNDAY FROM SFC HEATING AND WEAK INSTABILITY. ANY ACTIVITY WILL QUICKLY WEAKEN BY SUNSET WITH TEMPS MAINLY IN THE 70S FOR BOTH SAT/SUN AND LOWS IN THE 40S MTNS VALLEYS TO NEAR 60F CPV. MUCH WARMER AIR ARRIVES MONDAY INTO TUESDAY WITH PROGGED 85H TEMPS NEAR 15C BY 18Z TUESDAY...SUPPORTING HIGHS IN THE MID 80S WARMER VALLEYS. HAVE MENTION TEMPS 3 TO 5 DEGREES WARMER THAN THE SUPERBLEND GUIDANCE ON TUESDAY. ADDITIONAL CHCS FOR SHOWERS/STORMS ARRIVE LATE TUES INTO WEDS. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
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THROUGH 12Z THURSDAY...CURRENT RADAR SHOWS A CLUSTER OF STORMS WITH EMBEDDED LIGHTNING IS IMPACTING SOUTHERN VT. THESE STORMS WILL IMPACT RUTLAND AND MPV BTN 12-15Z WITH SOME LIGHTNING AND BRIEF HEAVY RAINFALL AND MVFR VIS/CIGS. ELSEWHERE...ADDITIONAL SHOWERS WITH EMBEDDED IFR CONDITIONS ARE OCCURING OVER THE SLV...AND MAY IMPACT MSS THRU 15Z. EXPECT A MIX OF VFR/MVFR THIS MORNING WITH ADDITIONAL STORMS BY EARLY THIS AFTN. SOME OF THE STRONGER STORMS WILL BE CAPABLE OF BRIEF GUSTY WINDS...LIGHTNING...AND HEAVY DOWN POURS...WHICH WILL REDUCE VIS BLW 3SM AT TIMES. HAVE USED A TEMPO GROUP BTWN 16Z AND 19Z TO COVER THUNDERSTORM POTENTIAL THIS AFTN...WITH GREATEST CONCENTRATION OF STORMS OVER OUR CENTRAL/EASTERN TAF SITES...BTV/PBG/RUT/MPV/SLK. SLOW CLEARING WITH VFR CONDITIONS WILL DEVELOP BY EVENING. OUTLOOK 12Z THURSDAY THROUGH MONDAY... VFR WITH WEAK SFC HIGH PRES...EXCEPT FOR IFR IN FOG/BR AT MPV/SLK BTWN 06Z AND 12Z THURS AND AGAIN ON FRIDAY. UNCERTAINTY ON SHOWER POTENTIAL THIS WEEKEND...WITH LATEST TRENDS SHOWING THE POTENTIAL FOR ADDITIONAL ISOLATED SHOWERS SATURDAY AND AGAIN ON SUNDAY...WITH BRIEF MVFR CIGS POSSIBLE AT SLK/MPV.
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&& .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...BANACOS NEAR TERM...BANACOS SHORT TERM...BANACOS LONG TERM...TABER AVIATION...TABER

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