Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 040004 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 804 PM EDT SUN MAY 3 2015 .SYNOPSIS... SURFACE HIGH PRESSURE WILL SHIFT INTO EASTERN NEW ENGLAND TONIGHT...WHILE A WEAK COLD FRONT APPROACHES THE NORTH COUNTRY ON MONDAY. THIS FRONT WILL PRODUCE BREEZY SOUTHWEST WINDS ON MONDAY...ESPECIALLY ACROSS NORTHERN NEW YORK WITH TEMPERATURES WARMING WELL INTO THE 70S AND LOWER 80S. THESE WARM TEMPERATURES... BREEZY WINDS...AND VERY DRY CONDITIONS...WILL CREATE NEAR CRITICAL FIRE WEATHER CONDITIONS OVER PORTIONS OF THE AREA ON MONDAY. SCATTERED SHOWERS WILL ACCOMPANY THE FRONT ON MONDAY NIGHT WITH COOLER AIR ARRIVING ON TUESDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 715 PM EDT SUNDAY...SHALLOW CONVECTION THAT FORMED TODAY PRODUCED SOME VIRGA...BUT DRY AIR IN THE LOW LEVELS QUICKLY EVAPORATED THE PRECIPITATION. AREAL COVERAGE OF THIS WEAK CONVECTION IS DECREASING AS LOW LEVEL LAPSE RATES START TO STABILIZE. HAVE REMOVED ANY MENTION OF LIGHT SHOWERS FOR THE REMAINDER OF THE EVENING. ONLY OTHER CHANGE WAS TO TWEAK TEMPERATURES AND DEW POINTS AS MUCH LIKE YESTERDAY...IT REMAINS WARMER AND DRIER LATER IN THE DAY...SO HAVE ADJUSTED ACCORDINGLY. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 320 PM EDT SUNDAY...THE FORECAST FOCUS ON MONDAY WILL BE POTENTIAL CRITICAL FIRE WEATHER CONDITIONS...FROM THE COMBINATION OF LOW RH VALUES...BREEZY SOUTHWEST WINDS...AND VERY DRY FINE FUELS FROM THE LACK OF SIGNIFICANT RAINFALL LATELY. SEE FIRE WEATHER SECTION BELOW FOR COMPLETE DETAILS. ON THE SYNOPTIC SCALE...A SURFACE COLD FRONT WILL BE APPROACHING THE SAINT LAWRENCE VALLEY AND NORTHERN ADIRONDACKS LATE MONDAY AFTERNOON...WHICH WILL INCREASE THE PRES GRADIENT ACROSS OUR NORTHERN AND WESTERN CWA ON MONDAY AFTERNOON. BTV 4KM AT KMSS SHOWS DEEP MIXING WILL OCCUR ON MONDAY AFTERNOON THRU 750MB...WHICH SUPPORTS TRANSPORT WINDS TO THE SFC BETWEEN 35 AND 40 KNOTS. ALSO...FAVORABLE ALIGNED SOUTHWEST TO NORTHWEST FLOW WITH ORIENTATION OF THE SAINT LAWRENCE VALLEY...WILL HELP TO ENHANCE WIND SPEEDS ACROSS THIS REGION ON MONDAY AFTERNOON. EXPECTING SLIGHTLY LESS WIND AT SARANAC LAKE...DUE TO LOCATION OF STRONGEST 925MB TO 850MB WIND FIELDS ACROSS THE SAINT LAWRENCE VALLEY...BUT THINKING GUSTS BETWEEN 30 AND 35 MPH WILL BE POSSIBLE. MEANWHILE...SOUNDINGS AT PLATTSBURGH/BTV AND NEWPORT VT...SHOW GOOD DEEP LAYER MIXING...BUT THE LOW LEVEL WIND FIELD IS WEAKER...SUPPORTING SFC WIND GUSTS BETWEEN 25 AND 30 MPH. THE WIND IS EXPECTED TO BE WEAKER OVER CENTRAL...EASTERN...AND SOUTHERN VT ON MONDAY...WITH THE STRONGEST WIND FIELDS AND ASSOCIATED GRADIENT TO THE NORTH. THIS MIXING WILL ALSO HELP TO TRANSFER SLIGHTLY DRIER AIR AROUND 850MB TO THE SURFACE ON MONDAY BEFORE DEEPER MOISTURE ARRIVES WITH BOUNDARY...SUPPORTING MINIMUM RH VALUES IN THE 22% TO 28% SOUTHERN SECTION TO 28% TO 38% IN THE NORTH ON MONDAY. PROGGED 85H TEMPS WARM ANOTHER DEGREE OR TWO...WITH VALUES BETWEEN 8-10C ON MONDAY...SUPPORTING HIGHS IN THE MID 70S MTNS TO L80S VALLEYS...WITH MAYBE A FEW MID 80S IF ENOUGH SUN OCCURS. SIGNIFICANTLY COOLER AND MORE HUMID NEAR THE INFLUENCE OF LAKE CHAMPLAIN. MEANWHILE...850 TO 500 MB MOISTURE WILL INCREASE FROM NORTHWEST TO SOUTHWEST ACROSS OUR CWA LATE MONDAY...PRODUCING SOME CLOUDS AND CHANCES FOR RAIN SHOWERS TOWARD SUNSET...ESPECIALLY SAINT LAWRENCE VALLEY. BASED ON PROGGED POSITION OF NARROW RIBBON OF ENHANCED MID LVL MOISTURE WILL MENTION CHANCE POPS SAINT LAWRENCE VALLEY BY 00Z TUESDAY AND SLIGHT CHANCE FOR NORTHERN ADIRONDACKS. SFC BOUNDARY AND ASSOCIATED LIFT WILL CONT TO IMPACT OUR CWA ON MONDAY NIGHT INTO TUESDAY...WITH SCATTERED SHOWERS. GIVEN SOUTHWEST FLOW OF 35 TO 45 KNOTS...EXPECT QPF/POP SHADOWING ACROSS THE CHAMPLAIN VALLEY...WITH VERY LIGHT PRECIPITATION EXPECTED. THINKING QPF WILL BE MAINLY TERRAIN TERRAIN...WITH THE HIGHEST QPF VALUES BETWEEN 0.10 AND 0.20 OF AN INCH ACROSS THE ADIRONDACKS AND PORTIONS OF THE NORTHERN GREEN MTNS ON MONDAY NIGHT. A RUMBLE OF THUNDER IS POSSIBLE MONDAY EVENING...WITH FRONT...BUT SFC INSTABILITY IS MINIMUM WITH CAPE VALUES < 200 J/KG SO WILL NOT MENTION AT THE MOMENT. GIVEN INITIALLY THE VERY DRY SFC CONDITIONS...EXPECT SOME PRECIPITATION TO FALL AS VIRGA...ESPECIALLY MONDAY EVENING. WILL MENTION LIKELY POPS MTNS AND CHANCE ELSEWHERE. TEMPS WILL COOL INTO THE 40S MTNS AND 50S VALLEYS...HIGHER THAN PREVIOUS COUPLE OF NIGHTS...BECAUSE OF CLOUDS AND WIND. TUESDAY-TUESDAY NIGHT...SFC BOUNDARY AND ASSOCIATED MOISTURE WILL BE JUST SOUTH OF OUR CWA BY 12Z TUESDAY...BUT EXPECT MOSTLY CLOUDY SKIES. WILL CONT TO CARRY CHANCE POPS ACROSS THE SOUTHERN CWA...JUST IN CASE A SLOWER FRONTAL PASSAGE OCCURS. PROGGED 85H TEMPS DROP SEVERAL DEGREES ON TUESDAY AND SUPPORT HIGHS MAINLY IN THE 60S TO NEAR 70...STILL SEVERAL DEGREES ABOVE NORMAL. NORTH TO NORTHWEST WINDS 10 TO 15 MPH WITH GUSTS TO 20 MPH WILL BE POSSIBLE ON TUESDAY AFTERNOON...WITH WINDS BECOMING LIGHT AFT SUNSET. SFC RIDGE WITH MAINLY CLEAR SKIES AND COOL TEMPS EXPECTED ON TUESDAY NIGHT. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 254 PM EDT SUNDAY...MAINLY DRY AND PLEASANT SPRING WEATHER WEDNESDAY INTO FRIDAY FOLLOWED BY INCREASING CHANCES FOR SHOWERS AS WE HEAD INTO NEXT WEEKEND. TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE PERIOD. ECMWF AND GFS MODELS IN RATHER GOOD AGREEMENT FOR MUCH OF THE PERIOD RESULTING IN HIGH FORECASTER CONFIDENCE. A RIDGE OF HIGH PRESSURE WILL PREVAIL ACROSS THE REGION WEDNESDAY THROUGH THURSDAY NIGHT...WITH FAIR AND DRY WEATHER EXPECTED. WARM FRONT LIFTS NORTH OF THE AREA ON FRIDAY. EXPECT SOME CLOUDS...BUT RISK OF PRECIPITATION RATHER LOW. HAVE CONTINUED TO INDICATE JUST SLIGHT CHANCE POPS FOR A FEW RAIN SHOWERS. A WEAK COLD FRONT WILL MOVE SOUTH FROM CANADA FRIDAY NIGHT INTO SATURDAY AND THEN BECOME STATIONARY SOMEWHERE ACROSS THE NORTHEAST NEXT WEEKEND. LITTLE UPPER LEVEL SUPPORT HOWEVER...AS 500 MB RIDGE REMAINS OVER THE REGION. EXPECT VARIABLE CLOUDS AND THE CHANCE FOR A FEW SHOWERS BOTH DAYS ALONG WITH A SLIGHT CHANCE OF THUNDERSTORMS SATURDAY. MAX TEMPS WILL AVERAGE A GOOD 5 TO 10 DEGREES ABOVE NORMAL THROUGH THE PERIOD...WITH HIGHS MOSTLY IN THE UPPER 60S TO MID 70S. THE WARMEST DAY IS SHAPING UP TO BE FRIDAY WHEN 850 MB TEMPS REACH +12 TO +14C. WITH SOME SUN...80 DEGREES CERTAINLY REACHABLE. CLEAR NIGHTS EARLY IN THE PERIOD WILL ALLOW FOR DECENT RADIATIONAL COOLING WITH LOWS IN THE UPPER 30S TO MID 40S. RETURN OF CLOUDS WILL PREVENT TEMPS FROM COOLING AS MUCH LATE IN THE WEEK AND NEXT WEEKEND WITH LOWS IN THE UPPER 40S TO MID 50S. && .AVIATION /00Z MONDAY THROUGH SATURDAY/...
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THROUGH 00Z TUESDAY...VFR CONDITIONS TO START THE PERIOD AS THE WEAK RIDGE OF HIGH PRESSURE OVER THE REGION WILL GIVE WAY AS A COLD FRONT APPROACHES THE NORTH COUNTRY. LOOK FOR MAINLY CLEAR SKIES TONIGHT THROUGH MONDAY MORNING. MID LEVEL CLOUDS MOVING INTO THE AREA LATE MORNING...ALONG WITH AFTERNOON CUMULUS AND SOME ISOLATED SHOWERS MAINLY IN THE SAINT LAWRENCE VALLEY...WITH POSSIBLE SHOWERS AS WELL IN THE CHAMPLAIN VALLEY LATE IN THE PERIOD. WINDS GENERALLY LIGHT AND VARIABLE TONIGHT. WINDS INCREASE FROM THE SOUTH TO SOUTHWEST MONDAY WITH GUSTS 20-30 KNOTS AROUND MID DAY...MAINLY AT KMSS/KSLK/KPBG/KBTV. OUTLOOK 00Z TUESDAY THROUGH SATURDAY... 00Z TUESDAY-00Z WEDNESDAY...MAINLY VFR BUT WITH AREAS OF MVFR/IFR IN SHOWERS AS A WEAK COLD FRONT MOVES THROUGH THE REGION. 00Z WEDNESDAY-00Z SATURDAY...VFR CONDITIONS WITH WEAK SURFACE HIGH PRESSURE PREVAILING FOR MUCH OF THE PERIOD.
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&& .FIRE WEATHER... BREEZY SOUTH TO SOUTHWEST WINDS OF 10 TO 20 MPH WITH GUSTS TO 30 MPH WILL OCCUR BETWEEN 11 AM AND 4 PM MONDAY....WITH MINIMUM RELATIVE HUMIDITY VALUES BETWEEN 28% AND 38%. A FEW HIGHER GUSTS TO NEAR 40 MPH WILL BE POSSIBLE IN THE SAINT LAWRENCE VALLEY AND PARTS OF THE NORTHERN ADIRONDACKS. THE STRONGEST WINDS WILL BE LOCATED ACROSS THE SAINT LAWRENCE VALLEY...NORTHERN ADIRONDACKS...AND PARTS OF THE CHAMPLAIN VALLEY INTO NORTHERN VT...WHILE THE LOWEST RH VALUES WILL BE ACROSS SOUTHERN VT. THESE CONDITIONS COMBINED WITH 60 TO 90 DAY DEPARTURE FROM NORMAL PRECIPITATION DEFICITS OF 2 TO 4 INCHES HAVE RESULTED IN FINE FUELS BECOMING VERY DRY BELOW 2000 FEET...ACCORDING TO THE VERMONT DEPARTMENT OF FOREST...PARKS AND REC AND NEW YORK STATE DEPARTMENT OF ENVIRONMENTAL CONSERVATION. GIVEN THE NEAR CRITICAL FIRE WEATHER CONDITIONS...WE WILL HIGHLIGHT POTENTIAL THREAT WITH A SPECIAL WEATHER STATEMENT AT THIS TIME. AS A SURFACE COLD FRONT APPROACHES THE SAINT LAWRENCE VALLEY AND NORTHERN ADIRONDACKS AFTER 3 PM MONDAY...RELATIVE HUMIDITY VALUES WILL INCREASE AS CLOUDS AND ASSOCIATED MID LEVEL MOISTURE OVERSPREAD THE REGION...WITH SCATTERED RAIN SHOWERS DEVELOPING BY EVENING. THESE SHOWERS WILL SPREAD EAST INTO THE CHAMPLAIN VALLEY AND MOST OF VERMONT OVERNIGHT...BUT PRECIPITATION WILL BE LIGHT AND MAINLY CONFINED TO THE MTNS. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...TABER NEAR TERM...EVENSON SHORT TERM...TABER LONG TERM...RJS AVIATION...EVENSON/MV FIRE WEATHER...TABER

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