Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 221122 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 722 AM EDT TUE JUL 22 2014 .SYNOPSIS... HIGH PRESSURE WILL REMAIN ATOP THE REGION TODAY INTO TONIGHT WITH WARM AND DRY WEATHER CONTINUING. A COLD FRONT WILL APPROACH AND CROSS THE AREA WEDNESDAY INTO WEDNESDAY EVENING WITH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS...A FEW OF WHICH MAY BE STRONG TO LOCALLY SEVERE. BEHIND THE FRONT...A RETURN TO MAINLY DRY AND SEASONAL WEATHER IS EXPECTED BY THURSDAY INTO THE FIRST HALF OF THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 718 AM EDT TUESDAY...NOISE LEVEL TWEAKS TO SKY COVER AND HOURLY T/TDS TO MATCH CURRENT OBSERVATIONAL TRENDS AND TO BLEND INTO EXISTENT DATA AT THE 9/10 AM HOUR. NO APPRECIABLE CHANGES TO GOING FORECAST. PRIOR DISCUSSION FOLLOWS... PRIOR DISCUSSION FROM 330 AM EDT TUESDAY...ANOTHER MAINLY SUNNY AND WARM DAY ON TAP FOR THE REGION AS DEEP LAYER HIGH PRESSURE REMAINS ACROSS THE REGION. BUILDING HEIGHTS AND MID/UPPER LEVEL ANTICYCLONIC FLOW SHOULD FOSTER BROAD SCALE SUBSIDENCE...SO LOOKING AT ONLY A FEW FAIR WX SHALLOW CUMULUS CLOUDS...MAINLY ACROSS THE HIGHER TERRAIN WITH NIL POPS. MODEL AVERAGED 18-00Z 925 MB TEMPS SUPPORT HIGHS WELL INTO THE 80S WITH A FEW SPOT L90S IN THE BROADER VALLEYS. WINDS LIGHT. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... AS OF 330 AM EDT TUESDAY...QUIET WX CONTINUES TONIGHT AS HIGH PRESSURE SLIDES SLOWLY EAST AND OFFSHORE...MAINTAINING A LIGHT SOUTHERLY FLOW ACROSS THE REGION. AN APPROACHING COLD FRONT TO OUR WEST MAY TEND TO SPREAD SCT MID TO HIGH LEVEL CLOUD COVER INTO OUR WESTERN COUNTIES LATER AT NIGHT...BUT OUTSIDE A STRAY SLV SHOWER TOWARD SUNRISE WE`LL REMAIN DRY OVERNIGHT. LOWS CONTINUE MILD GENERALLY IN THE 60S TO LOCALLY NEAR 70F IN THE CHAMPLAIN VALLEY. BRIEF...THOUGH ACTIVE PERIOD OF WEATHER THEN DEVELOPS DURING WEDNESDAY INTO EARLY WEDNESDAY EVENING AS AFOREMENTIONED COLD FRONT MAKES STEADY PROGRESS THROUGH THE AREA. DECENT 0-6KM SHEAR PROFILES AND AMPLE PBL INSTABILITY IN EXCESS OF 1000 J/KG SHOULD BE MORE THAN ENOUGH TO SUPPORT SCT/NUMEROUS SHOWERS AND STORMS ACROSS THE AREA...A FEW OF WHICH MAY BECOME STRONG TO LOCALLY SEVERE. PRE-FRONTAL CLOUDS AND MORNING SHOWERS MAY LIMIT THREAT ACROSS THE SLV AND TO SOME EXTENT THE ADIRONDACKS...BUT SUCH SUBTLE TIMING DIFFERENCES WILL BE ALLOWED TO PLAY OUT AND HAVE MENTIONED THIS THREAT IN ALL AREAS FOR NOW...IN CLOSE AGREEMENT TO SPC SWODY2. GUSTY/STRONG WINDS AND HEAVY DOWNPOURS (PWATS TO NEAR 2") APPEAR TO BE THE MAIN THREAT WITH LARGE HAIL A LESSER CONCERN GIVEN DEEPER WCD VALUES AND WBZ HEIGHTS ABOVE 11 KFT. CONVECTIVE MODE WOULD BE LINEAR WITH POSSBL QLCS DEVELOPMENT ACROSS OUR EASTERN COUNTIES WITH RELATIVELY UNIDIRECTIONAL WIND PROFILES THROUGH THE PBL. ALSO CAN`T RULE OUT LOCALIZED HYDRO CONCERNS GIVEN THE WCD DEPTHS AND HIGH PWAT VALUES...BUT WIND FIELDS APPEAR STRONG ENOUGH TO KEEP MOST OF THE ACTIVITY MOVING ALONG AND GIVEN THE RELATIVELY DRY ANTECEDENT CONDS MOST WATERSHEDS SHOULD BE ABLE TO HANDLE THINGS OK. BY WEDNESDAY NIGHT SFC FRONT CLEARS EAST AND SOUTH WITH SHOWERS/STORMS ENDING ACROSS OUR SOUTHERN VT COUNTIES BY MIDNIGHT OR SO AND SKIES GRADUALLY TRENDING PC/CLR ACROSS THE NORTH OVERNIGHT. LOWS A BLEND OF MODEL GUIDANCE...MAINLY 50S. SFC HIGH PRESSURE THEN BUILDS EAST/SOUTH INTO THE FORECAST AREA BY THURSDAY WITH CYCLONIC FLOW PERSISTING ALOFT UNDER BASE OF MEAN ERN CANADA UPPER LONGWAVE TROUGH. UPWARD MOISTURE FLUXES FROM PRIOR EVENING`S RAINFALL COMBINED WITH STRONG JULY SUN SHOULD LEAD TO DECENT COVERAGE OF FAIR WX CUMULUS CLOUDS...ESP ACROSS THE HIGHER TERRAIN. HOWEVER...ALL AND ALL A VERY NICE DAY IS EXPECTED WITH LOWER HUMIDITY VALUES AND LIGHT NORTHERLY BREEZES AS HIGHS RANGE THROUGH THE 70S. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 357 AM EDT TUESDAY...FAIRLY GOOD AGREEMENT AMONGST THE 00Z GUIDANCE SUITE FOR THE LATTER PART OF THE WEEK INTO THE EARLY WEEKEND. THEREAFTER DETAIL DIFFERENCES EMERGE BETWEEN 00Z GFS...ITS ENSEMBLE MEAN AND 00Z ECMWF IN THE EVOLUTION AND ULTIMATE RETROGRESSION OF A NORTHEASTERN NOAM MID-LEVEL TROUGH FOR LATE WEEKEND/EARLY NEXT WEEK. THE SOURCE OF THOSE DIFFERENCES STEMS FROM HOW QUICKLY TO PHASE A SHEARING-OUT SHORTWAVE ENTERING THE CANADIAN PRAIRIES WITH THE EASTERN NOAM TROUGH. OVERALL PATTERN FAVORS UNSETTLED CONDITIONS LATE WEEKEND INTO EARLY NEXT WEEK WITH CLOUDY/OFF-AND-ON SHOWERS AND THUNDER - BUT NOTHING THAT SEEMS TOO SIGNIFICANT. DESPITE PREVAILING CYCLONIC MID-LEVEL FLOW THROUGH MUCH OF THE PERIOD...TEMPS WILL TEND TO RUN AROUND NORMAL. MOSTLY CLEAR SKIES AND LIGHT SFC WINDS THURSDAY NIGHT SHOULD PROMOTE STRONG RADIATIONAL COOLING. THURDSDAY NIGHT LOOKS TO BE THE COOLEST NIGHT IN THE PERIOD (MID 40S TO VALLEY MID 50S). I DIDN`T INTRODUCE INTO THE FORECAST YET BUT RIVER VALLEY FOG LOOKS TO BE A GOOD POSSIBILITY THURS NIGHT AS WELL GIVEN WET SOIL CONDITIONS FROM EXPECTED RAINFALL WEDNESDAY/WED NIGHT. CYCLONIC FLOW ALOFT COMBINED WITH DAYTIME HEATING FRIDAY WILL LIKELY PRODUCE AT LEAST PARTLY CLOUDY SKIES WITH SLIGHT CHANCE TO CHANCE POPS MORE FOCUSED TO THE HIGHER TERRAIN. THERE ISN`T MUCH MOISTURE TO WORK WITH BUT COULDN`T REALLY DISCOUNT SOME ISOLATED TO SCATTERED SHOWERS. OPTED FOR A DRY FORECAST FOR THE FIRST HALF OF SATURDAY AS THE MID-LEVEL TROUGH AXIS PIVOTS NORTHEAST WITH NEUTRAL TO SLIGHT HEIGHT RISES. THE REST OF THE WEEKEND INTO EARLY NEXT WEEK HAS SLIGHT CHANCE/CHANCE POPS GRADUALLY INCREASING TO HIGH-CHANCE TOWARD EARLY NEXT WEEK AS THE LARGE-SCALE TROUGH RETROGRADES TOWARD THE GREAT LAKES...LEAVING THE NORTH COUNTRY UNSETTLED IN SOUTHWEST FLOW ALOFT. TEMPS FOR SATURDAY INTO TUESDAY PRETTY SIMILAR...HIGHS IN THE 70S TO LOW 80S AND LOWS IN THE 50S TO LOW 60S. && .AVIATION /11Z TUESDAY THROUGH SATURDAY/... THROUGH 12Z WEDNEDSAY...VLIFR FOG AT SLK BURNS OFF EARLY THIS MORNING WITH VFR EXPECTED FOR ALL TAF SITES. A FEW-SCT CU POSSIBLE AT MPV AND SLK NEAR TERRAIN BUT OTHERWISE UPPER-LEVEL RIDGING LARGELY SUPPRESSES CU DEVELOPMENT TODAY. WILL SEE AN INCREASE IN CIRRUS LATE IN THE DAY AND ESPECIALLY EVENING/OVERNIGHT WELL AHEAD OF FRONTAL SYSTEM. ANY RAIN/T-STORMS LOOK TO HOLD OFF UNTIL AFTER 12Z WEDNESDAY HOWEVER. MIST/FOG UNLIKELY TONIGHT GIVEN INCREASING CLOUDS AND PROGGED 10-15 KT BL WINDS. WINDS MOSTLY SOUTHERLY UNDER 10 KTS (INITIALLY SE AT PBG THIS MORNING FROM LAKE BREEZE). OUTLOOK 12Z WEDNESDAY THROUGH SATURDAY... 12Z WED - 06Z THU...VFR WITH BRIEF PERIOD MVFR/IFR IN HEAVY SHOWERS/T-STORMS WITH FRONTAL PASSAGE. STORMS WEDNESDAY COULD BE STRONG...CAPABLE OF TURBULENCE AND HEAVY DOWNPOURS WITH LIMITED RISK OF SMALL HAIL. 06Z THU - 12Z THU...MOST TAFS VFR. HOWEVER...POSSIBLE IFR OR LOWER VISIBILITY IN FOG/MIST AT SLK AND POSSIBLY MPV PENDING CLEARING. 12Z THU - 00Z FRI...VFR UNDER HIGH PRESSURE DURING THE DAY THURSDAY. 00Z FRI - 12Z FRI...IFR OR LOWER VISIBILITY IN FOG/MIST MPV AND SLK...OTHERWISE VFR. 12Z FRI - 00Z SUN...VFR UNDER SURFACE HIGH PRESSURE. AN ISOLATED AFTERNOON SHOWER OVER THE HIGHER TERRAIN IS POSSIBLE FRIDAY. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JMG NEAR TERM...JMG SHORT TERM...JMG LONG TERM...LOCONTO AVIATION...LOCONTO

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