Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 020727 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 327 AM EDT TUE JUN 2 2015 .SYNOPSIS... A SURFACE TROUGH ACROSS NORTHERN NEW YORK WILL CONTINUE TO BRING COOL AND DAMP CONDITIONS TO THE NORTH COUNTRY TONIGHT THROUGH EARLY TUESDAY. UNDER OVERCAST SKIES...TEMPERATURES WILL ONLY FALL INTO THE MID 40S TONIGHT...WITH HIGHS GENERALLY 55 TO 60 DEGREES ON TUESDAY. AFTER A FOGGY START EARLY WEDNESDAY...SKIES WILL BECOME MOSTLY SUNNY COURTESY OF HIGH PRESSURE BUILDING INTO THE REGION FROM THE NORTHWEST. DRY WEATHER IS EXPECTED WEDNESDAY AND THURSDAY...WITH MODERATING TEMPERATURES. A WEAK FRONTAL BOUNDARY WILL BRING A FEW SHOWERS FRIDAY AFTERNOON...WITH A RETURN TO DRY WEATHER AND HIGH PRESSURE FOR THE UPCOMING WEEKEND. HIGH TEMPERATURES THURSDAY THROUGH SUNDAY WILL GENERALLY BE IN THE 70S. && .NEAR TERM /UNTIL 7 AM THIS MORNING/... AS OF 1259 AM EDT TUESDAY...GOING FORECAST REMAINS IN GOOD SHAPE. ONLY MINOR CHANGES WITH LATEST UPDATE TO BLEND IN CURRENT CONDITIONS TO THE GOING FORECAST. STILL SOME LIGHT RADAR ECHOES PER RECENT COMPOSITE IMAGERY...CONSISTENT WITH VERY LIGHT RAIN/DRIZZLE IN AN OVERCAST AND SATURATED AIRMASS. RECENT HRRR OUTPUT CONTINUE TO POINT TO LIGHT RAIN OR DRIZZLE CONTINUING AS UPPER LOW APPROACHES FROM THE NORTHWEST. STEADIER RAINS WILL REMAIN WELL SOUTH OF THE NORTH COUNTRY CLOSER TO WEAK SURFACE WAVE LOW AND ACCOMPANYING INVERTED TROUGH OVER THE MID-ATLANTIC STATES INTO SOUTHERN NEW ENGLAND. TEMPS AND DEWPOINTS WILL STRUGGLE TO CHANGE VERY MUCH FROM PRESENT VALUES UNDER BLANKET OF OVERCAST SKIES AND NO SIGNIFICANT THERMAL OR MOISTURE ADVECTION TO SPEAK OF. LOWS IN THE MID TO UPPER 40S STILL LOOK ON TRACK. && .SHORT TERM /7 AM THIS MORNING THROUGH THURSDAY/... AS OF 256 PM EDT MONDAY...IT APPEARS THE LOW-LEVEL INVERTED TROUGH WILL GRADUALLY DISSIPATE ACROSS ERN NY DURING THE DAY TUESDAY. WILL SEE CLOSED 500MB LOW...CURRENTLY NORTH OF THE GREAT LAKES...ROTATE EASTWARD AND PASS JUST TO OUR NORTH DURING TUESDAY AFTERNOON. WHILE A FEW ADDITIONAL SHOWERS ARE POSSIBLE IN THE MORNING...MID-LEVEL DRYING AND LOSS OF SURFACE TROUGH SHOULD ALLOW SHOWERS TO DIMINISH BY TUESDAY AFTERNOON. WILL BE DIFFICULT TO SCOUR OUT STRATUS LAYER...SO ANTICIPATE CLOUDY SKIES WITH JUST A FEW AFTERNOON BREAKS IN THE OVERCAST. CLOUDS AND NORTH WINDS (5-10 MPH) WILL LIMIT DAYTIME HEATING ONCE AGAIN...YIELDING HIGH TEMPERATURES GENERALLY IN THE 55-60F. MAY SEE A FEW LOWER 60S IN THE SRN CHAMPLAIN VALLEY AND FOR PORTIONS OF SOUTHWESTERN ST. LAWRENCE COUNTY. FOR POPS...INDICATED CHANCE 40-50 PERCENT IN THE MORNING...GRADUALLY DECREASING TO SLIGHT CHANCE DURING THE AFTERNOON HOURS...TAPERING OFF FROM WEST TO EAST. SHOULD SEE CLEARING SKIES ON TUESDAY NIGHT AS CLOSED UPPER LEVEL LOW SHIFTS EASTWARD INTO THE CANADIAN MARITIMES. WILL SEE SURFACE RIDGE GRADUALLY BUILD INTO THE REGION FROM SOUTHEASTERN QUEBEC AND SERN ONTARIO. THE COMBINATION OF DIMINISHING WIND...CLEARING SKIES...AND THE AMPLE RAINFALL RECENTLY WILL LIKELY LEAD TO WIDESPREAD FOG FORMATION...WHICH COULD BE DENSE IN SPOTS BETWEEN 06-12Z WEDNESDAY. LOW TEMPERATURES ARE GENERALLY EXPECTED IN THE LOW TO MID 40S...BUT A FEW SPOTS IN FAR NORTHEASTERN VERMONT AND WITHIN THE NORTHERN ADIRONDACK REGION COULD FALL INTO THE MID TO UPPER 30S. THE FOG SHOULD PROVIDE JUST ENOUGH OF A BRAKE ON FALLING TEMPS THAT FROST APPEARS UNLIKELY IN THOSE OUTLYING AREAS AT THE MOMENT. SHOULD SEE FOG AND LINGERING STRATUS ERODE DURING WEDNESDAY MORNING AS BOUNDARY LAYER MIXES OUT. HIGH PRESSURE CRESTING OVER NEW ENGLAND DURING THE DAYLIGHT HRS...AND SHOULD TREND MOSTLY SUNNY BY AFTERNOON WITH RELATIVELY LIGHT WINDS. WENT A COUPLE OF DEGREES ABOVE MOS CONSENSUS...AS MIXING LOOKS A BIT TOO SHALLOW IN MODEL SOUNDINGS (PERHAPS DUE TO WET GROUND). WITH 850MB TEMPS +7 TO +9C...HIGHS IN THE UPPER 60S TO LOWER 70S LOOK BEST. CONTINUED QUIET WEDNESDAY NIGHT WITH PW VALUES <0.5IN AND 1000-500MB RH VALUES LESS THAN 30 PERCENT IN 12Z GFS. LIGHT WINDS WITH GOOD RADIATIONAL COOLING. MAY SEE SOME ADDITIONAL NOCTURNAL FOG...BUT SHOULDN`T BE AS WIDESPREAD AS TUESDAY NIGHT. LOWS GENERALLY IN THE MID TO UPPER 40S...BUT LOCALLY NEAR 40F AT SARANAC LAKE AND FAR NORTHEASTERN VERMONT. POPS NIL. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
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AS OF 323 AM EDT TUESDAY...HIGH PRESSURE SHOULD KEEP MOST OF THURSDAY EVENING AND FRIDAY MORNING DRY BEFORE AN UPPER LEVEL LOW AND ASSOCIATED COLD FRONT DROP SOUTH FROM CANADA BRINGING A CHANCE FOR SHOWERS AND THUNDERSTORMS ON FRIDAY NIGHT INTO SATURDAY MORNING. THE MODELS IN THE 00Z RUN CAME IN WITH A BIT MORE INCONSISTENCY WITH REGARDS FOR TIMING THAN I WOULD LIKE AT THIS POINT. THE GENERAL CONSENSUS IS THAT THE MODELS ARE STRUGGLING WITH HOW THE SOUTHERN SURGE OF WARM AIR ADVECTION AND MID LEVEL MOISTURE WILL MERGE WITH THE NORTHERN STREAM SYSTEM. BOTH THE CANADIAN AND ECMWF SHOW A FAIRLY WELL DEFINED FRONTAL SYSTEM MOVING ENTERING THE SAINT LAWRENCE VALLEY AND THEN PROPAGATING ACROSS THE REGION BEFORE FALLING APART BY 12Z SATURDAY MORNING. THE 00Z GFS WHICH HAD PREVIOUSLY SHOWN SOMETHING SIMILAR IS NOW SIGNIFICANTLY MORE PROGRESSIVE BRINGING THE FRONT THROUGH ABOUT 6-12 HOURS FASTER. THIS LEADS TO A CHALLENGING TEMPERATURE FORECAST FOR SATURDAY AS DEPENDING ON HOW FAR THE FRONT MAKES IT THROUGH THE AREA THE TEMPS WILL VARY WIDELY. THE FORECAST AS IT STANDS RIGHT NOW IS FOR TEMPS IN THE MID TO UPPER 60S ON SATURDAY UNDER THE MODERATE TO STRONG NORTHERLY COLD AIR ADVECTION BEHIND THE FRONT. CONCERNING THE SHOWERS AND POTENTIAL THUNDERSTORMS, THE MODELS ARE IN DECENT AGREEMENT WITH SOME WEAK TO MODERATE INSTABILITY MAINLY ALONG THE CONVERGENT ZONE WHERE THE FRONT MEETS UP WITH THE SOUTHERN STREAM OF ENERGY. WITH 30-40KTS OF 0-6KM SHEAR AND THE AFOREMENTIONED INSTABILITY A FEW THUNDERSTORMS WILL BE POSSIBLE SO I`VE GONE AHEAD AND ADDED WORDING OF THUNDER TO THE FORECAST. AS OF RIGHT NOW THE WEAK INSTABILITY WILL HOLD BACK THE DEVELOPMENT OF STRONG THUNDERSTORMS BUT THAT WILL BE SUBJECT TO FUTURE MODEL RUNS. BEHIND THE FRONT DRY AIR WILL MOVE IN WITH A BROAD DOME OF HIGH PRESSURE QUICKLY MOVING ACROSS THE REGION AS A 50-60KT 500MB JET STEERS THE HIGH TO THE EAST. THAT DRY AIR WILL BE SHORT LIVED HOWEVER AS THE MODELS ARE IN DECENT AGREEMENT THAT THERE WILL BE A SECOND LOW PRESSURE SYSTEM THAT WILL PASS THROUGH THE REGION EARLY NEXT WEEK. THERE ISN`T MUCH CONSENSUS ON TIMING OR INTENSITY SO FOR THE TIME BEING I`LL CONTINUE THE PREVIOUS FORECAST OF 40-50% CHANGE FOR SHOWERS FROM MONDAY MORNING THROUGH TUESDAY MORNING. WILL REFINE THAT WINDOW AS THE MODELS COME INTO MORE AGREEMENT IN FUTURE RUNS. TEMPS THROUGH THE EXTENDED WITH START OFF RIGHT AROUND CLIMO WITH MAX TEMPS ON FRIDAY IN THE MID TO LOW 70S AND OVERNIGHT LOWS IN THE MID TO LOW 50S. THEN AS THE FRONT COMES THROUGH TEMPS WILL DROP SOME 5-10 DEGREES ACROSS THE REGION WITH MAX TEMPS ONLY IN THE MID TO UPPER 60S SATURDAY AND LOWS OVERNIGHT IN THE UPPER 40S. WE WILL THEN REBOUND BACK TOWARDS CLIMO WITH HIGHS IN MID 70S AND LOWS IN THE MID 50S EARLY NEXT WEEK.
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&& .AVIATION /08Z TUESDAY THROUGH SATURDAY/... THROUGH 06Z WEDNESDAY...THE MIXED BAG OF VFR/MVFR/IFR WILL CONTINUE THROUGH THIS EVENING. MOST SITES WILL STAY PREDOMINATELY MVFR WITH CEILINGS IN THE 2000-3000 FT RANGE OVERNIGHT. THE MOST LIKELY AREAS OF IFR WILL BE AT MPV/SLK WHERE LOW STRATUS TO LIGHT FOG IS FORECAST. EXPECT THE PATCHY AREAS OF DRIZZLE TO WEAKEN THROUGH THE NIGHT WITH THE FORECAST AREA DRY BY 09Z. THROUGH THE OVERNIGHT HOURS WINDS WILL REMAIN LIGHT AND VARIABLE TO CALM FROM A GENERAL EAST TO NORTHEAST DIRECTION WITH THE EXCEPTION OF RUTLAND WHERE THE GAPS WINDS ARE HOLDING STRONGER IN THE 7-10 KT RANGE AND GUSTING 15-20TKS. TOMORROW AS WE START TO SEE SOME DAYTIME HEATING EXPECT THE MVFR/VFR CEILINGS TO GRADUALLY IMPROVE TO VFR ACROSS ALL TERMINALS TOMORROW AFTERNOON. HOWEVER TOMORROW EVENING WILL BE THE BETTER CHANCE OF RADIATIONAL FOG DEVELOPMENT AS BOUNDARY LAYER WINDS WILL GO MOSTLY CALM AND THE GROUND WILL BE SUFFICIENTLY MOIST AFTER THE RAINS FROM THE WEEKEND. I`VE ALREADY INCLUDED AT LEAST VISIBILITY OF 3 MILES AT SLK AND AS CONFIDENCE INCREASES WILL LIKELY ADD IN VISIBILITY RESTRICTIONS FOR ADDITIONAL TAF SITES. OUTLOOK 06Z WEDNESDAY THROUGH SATURDAY... 06Z WEDNESDAY THROUGH 12Z FRIDAY...MAINLY VFR WITH BUILDING HIGH PRESSURE. EXCEPTION WILL BE POTENTIAL FOR AREAS OF DENSE FOG AT ALL TERMINALS IN THE 02-13Z WEDNESDAY TIME FRAME. 12Z FRIDAY ONWARD...INCREASING CHANCE FOR SHOWERS WITH VFR/MVFR CONDITIONS AS A FRONTAL PASSAGE MOVES INTO THE AREA SATURDAY AFTERNOON. && .HYDROLOGY... THE FLOOD WATCH HAS BEEN CANCELLED. RIVERS WILL GRADUALLY RECEDE THIS EVENING AS PRECIPITATION RATES CONTINUE TO DIMINISH. THE EAST BRANCH OF THE AUSABLE RIVER BRIEFLY REACHED JUST ABOVE FLOOD STAGE EARLY TO MID AFTERNOON AT 7.0 FEET. THE MAD RIVER AT MORETOWN (MOOV1) BRIEFLY REACHED ACTION STAGE (BETWEEN 8-9 FEET)...BUT HAS SINCE FALLEN BELOW 8 FEET AND SHOULD CONTINUE DOWNWARD THIS EVENING AND TONIGHT. TOTAL RUNOFF IN THE CHAMPLAIN BASIN SHOULD RESULT IN LAKE CHAMPLAIN RISES FROM AROUND 96.5 FEET UP TO 96.8 FEET BY THURSDAY MORNING. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...BANACOS NEAR TERM...RJS/LOCONTO SHORT TERM...BANACOS LONG TERM...DEAL AVIATION...DEAL HYDROLOGY...BANACOS

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