Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 292339
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
739 PM EDT FRI MAY 29 2015

.SYNOPSIS...
SURFACE HIGH PRESSURE WILL BE OVER THE REGION THROUGH EARLY
SATURDAY. A STRONG SURFACE COLD FRONT WILL APPROACH FROM THE
NORTHWEST SATURDAY AFTERNOON AND CROSS THE AREA OVERNIGHT. THIS
FRONT WILL STALL OUT SOUTH OF OUR FORECAST AREA AND BECOME A FOCUS
FOR SEVERAL WAVES OF SHOWERS DURING THE FIRST PART OF THE WEEK.

&&

.NEAR TERM /UNTIL 8 AM SATURDAY MORNING/...
AS OF 739 PM EDT FRIDAY...FRIDAY AFTERNOON CLOSES WITH FILTERED
SUNSHINE ACROSS THE NORTH COUNTRY, AS MID-LEVEL MOISTURE SPILLS IN
ON THE WESTERN END OF A DEEP-LAYER ANTICYCLONE CENTERED OVER LONG
ISLAND/SOUTHERN NEW ENGLAND. THOUGH LOOKING AT A GENERALLY QUIET
EVENING ALL THINGS CONSIDERED, SURFACE ANALYSIS DEPICTS A SUBTLE
SURFACE TROUGH FROM WESTERN PA CURRENTLY TRIGGERING SHOWERS AND
THUNDERSTORMS IN THAT VICINITY. THAT TROUGH SEPARATES MORE
COMFORTABLE DEWPOINTS IN THE 50S IN PLACE, TO A MORE MOIST/HUMID
AIRMASS WITH MID-60S DEWPOINTS. THIS FEATURE WILL LIFT NORTHEAST
TOWARDS OUR AREA AFTER MIDNIGHT. MOST HI-RES GUIDANCE INDICATE A
GENERALLY DRY PASSAGE, BUT A FEW, SUCH AS THE BTV-4 WRF AND TO A
LESSER EXTENT MOST RECENT HRRR OUTPUT, SHOW SOME LIGHT SHOWERS
ACROSS ST. LAWRENCE VALLEY INTO THE ADIRONDACKS REGION AFTER
MIDNIGHT. FOR NOW, I`VE KEPT SLIGHT CHANCE SHOWERS GOING IN THIS
AREA AND WILL RE-EVAL WITH TRENDS IN RADAR AND LATER EVENING
GUIDANCE.

OTHERWISE, PRIMARY CHALLENGE WILL BE TIMING WHEN COOLING HALTS
ACROSS THE NORTH COUNTRY, IN THE FACE OF WARM/MOIST ADVECTION AND
INCREASING SOUTHWEST WINDS. THIS HAPPENS SOONER FURTHEST WEST
(TOWARD MIDNIGHT) WITH LONGER IN EASTERN VERMONT. LOWS TONIGHT
TO RANGE IN THE UPPER 50S IN EASTERN VERMONT, BUT WILL BE SOME 10
DEGREES WARMER IN THE CHAMPLAIN AND ST. LAWRENCE VALLEYS.

&&

.SHORT TERM /8 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 415 PM EDT FRIDAY...COLD FRONT APPROACHES FROM THE
NORTHWEST SATURDAY AND SHOWERS AND THUNDERSTORMS DEVELOP OUT AHEAD
OF THIS FEATURE ON SATURDAY AFTERNOON. BEST CHANCE FOR
THUNDERSTORMS APPEARS TO BE AFTER 18Z...AND MAINLY NORTHERN NEW
YORK AND THE CHAMPLAIN VALLEY. OUR REGION CONTINUES TO BE UNDER A
MARGINAL RISK OUT OF SPC. BETTER DYNAMICS AND STRONGER SHEAR WILL
BE WELL NORTH OF THE AREA...CLOSER TO STRONG SHORT WAVE TROF
MOVING ACROSS ONTARIO AND QUEBEC. DAYTIME MAX TEMPS WILL REACH THE
MID 70S TO MID 80S. CAPE VALUES REACH OVER 2000 IN THE SAINT
LAWRENCE VALLEY. OVERNIGHT AS THE FRONT CONTINUES ACROSS OUR
FORECAST AREA AND WITH LOSS OF DAYTIME HEATING EXPECT CONVECTION
TO END AND JUST SOME SHOWERS CONTINUING. COLD FRONT WILL STALL OUT
TO OUR SOUTH AND BECOME THE FOCUS FOR SEVERAL ROUNDS OF
PRECIPITATION. SUNDAY NIGHT WILL SEE SHOWERS MOVE ACROSS NEW YORK
AND SOUTHERN NEW ENGLAND...HAVE SOME LIKELY POPS MENTIONED IN OUR
SOUTHERN ZONES. TEMPERATURES WILL BE MUCH COOLER ON SUNDAY AS
REGION IS IN THE COOL SECTOR BEHIND COLD FRONT...MAX TEMPS WILL
ONLY BE IN THE UPPER 50S AND LOWER 60S...A GOOD 20 DEGREES COOLER
THAN SATURDAY. SUNDAY NIGHT TEMPERATURES WILL DROP INTO THE 40S.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 400 PM EDT FRIDAY...RATHER TRANQUIL EXTENDED FORECAST PERIOD
FORESEEN BASED ON CONSENSUS OF 00Z GFS/GFS ENSEMBLE MEAN AND 00Z
ECMWF. DEEP-LAYER NWLY FLOW ON ERN PERIPHERY OF SFC ANTICYCLONE
BUILDING EWD FROM THE GREAT LAKES REGION WILL PROVIDE DRIER
CONDITIONS AND MORE SEASONABLE TEMPERATURES TO START THE PERIOD
WEDNESDAY NIGHT. ANTICIPATE MOSTLY CLEAR SKIES...AND IF SURFACE
WINDS DROP OFF SUFFICIENTLY...SHOULD SEE OVERNIGHT LOWS RANGING
FROM NEAR FREEZING IN THE NORTHERN ADIRONDACKS AND FAR
NORTHEASTERNVT...TO AROUND 40F IN THE CHAMPLAIN VALLEY REGION.
AFOREMENTIONED SURFACE HIGH BUILDS SLOWLY EWD ACROSS THE
NORTHEASTERN CONUS PROVIDING PLEASANT/MOSTLY CLEAR CONDITIONS
THURSDAY THROUGH AT LEAST THE FIRST HALF OF FRIDAY. HIGHS WILL BE
IN THE MID 60S THURSDAY...BEFORE MODERATING BACK INTO THE LOW 70S
ON FRIDAY.

SOME DIFFERENCES BETWEEN 00Z GFS AND 00Z ECMWF CONCERNING
POTENTIAL SHORTWAVE TROUGH MOVING EWD FROM THE GREAT LAKES FRIDAY
NIGHT INTO SATURDAY. THE GFS IS MORE ROBUST WITH THIS
FEATURE...AND TRACKS STRONGEST UVV ACROSS OUR SRN ZONES LATE
FRIDAY NIGHT INTO SATURDAY. THE 00Z ECMWF - ON THE OTHER HAND -
KEEPS BEST PRECIPITATION CHANCES TO OUR SOUTH. THE OFFICIAL
FORECAST INDICATES SOME INCREASING CLOUDS LATER FRIDAY...FOLLOWED
BY 15-30 POPS FOR SHOWER ACTIVITY FRIDAY NIGHT THRU
SATURDAY...WITH HIGHEST POP VALUES ACROSS SRN ZONES. CLOUDS COULD
KEEP TEMPS IN THE UPR 60S TO AROUND 70F FOR SATURDAY...BEFORE
TRENDING WARMING (LOW-MID 70S) WITH BETTER POTENTIAL FOR SUNSHINE
ON SUNDAY.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 00Z SUNDAY...VFR (POSSIBLE MVFR MIST AT MPV) WITH
INCREASING SOUTH WINDS THROUGH OVERNIGHT. PRIMARY AVIATION FOCUS
WILL BE IN THE LATTER HALF OF THE TAF PERIOD, DUE TO GUSTY SOUTH
WINDS AND POTENTIAL FOR SHOWERS AND THUNDERSTORMS INTO SATURDAY
AFTERNOON/EVENING.

MOSTLY CLEAR WITH SCT-BKN CIRRUS CLOUDS INTO THE OVERNIGHT
TONIGHT. I`VE CONTINUED MENTION OF 4SM BR AT MPV AFTER 08Z,
THOUGH ENOUGH LOW-LEVEL FLOW MAY PRECLUDE MUCH IF ANY MIST FROM
DEVELOPING. INITIALLY LIGHT/VARIABLE WINDS BUT BECOME SOUTH 7-10
KTS.

CONTINUED MID- TO HIGH CLOUDS INTO SATURDAY. STRENGTHENING
GRADIENT AHEAD OF SURFACE COLD FRONT SHOULD ALSO ALLOW FOR
SOUTHERLY WINDS TO FURTHER INCREASE INTO THE 10-15 KT RANGE WITH
GUSTS 25-28 KTS. SHOWER/THUNDERSTORM COVERAGE LIKELY TO BE MORE
SCATTERED, BUT THREAT SOME COULD TURN STRONG WITH GUSTY OUTFLOW
WINDS, LIGHTNING AND REDUCED VISIBILITY IN HEAVY DOWNPOURS.
BEST SHOT AT SEEING THIS ACTIVITY AFTER 18Z WOULD BE AT MSS AND
SLK, BUT I`VE ALSO SHOWN VCSH AT BTV AND PBG. MPV AND SLK NOT
LIKELY TO SEE THIS ACTIVITY UNTIL AFTER 00Z.

OUTLOOK 00Z SUNDAY THROUGH WEDNESDAY...A SURFACE COLD FRONT
APPROACHING FROM SOUTHEASTERN ONTARIO WILL BRING SCATTERED SHOWERS
AND THUNDERSTORMS ON SATURDAY AFTERNOON INTO SATURDAY NIGHT. SOME
STORMS COULD BE STRONG WITH LOCALIZED GUSTY AND ERRATIC OUTFLOW
WINDS...HEAVY RAINFALL...AND FREQUENT LIGHTNING...MAINLY MID
AFTERNOON THROUGH EARLY EVENING HOURS SATURDAY. BRIEF IFR
CONDITIONS CAN BE EXPECTED WITH ANY THUNDERSTORM ACTIVITY.
MODERATELY STRONG GRADIENT WINDS (SOUTH TO SOUTHWEST AT 15-25 KTS)
WILL CONTINUE THROUGH THE EARLY EVENING PERIOD. PERIODS OF RAIN
CONTINUE DURING SATURDAY NIGHT WITH DEVELOPING N-NW WINDS BEHIND
THE SURFACE COLD FRONT. TRENDING VFR ACROSS NORTHERN AREAS DURING
THE DAYLIGHT HOURS SUNDAY...BUT STALLING FRONTAL ZONE MAY RESULT
IN POSSIBLE MVFR SHOWERS AT TIMES SUNDAY NIGHT INTO
MONDAY...MAINLY FOR RUT/MPV. AVIATION WX CONDITION PREDICTABILITY
LOW AT THIS POINT FROM MONDAY NIGHT THRU WEDNESDAY.

&&

.MARINE...
AS OF 400 PM EDT FRIDAY...A COLD FRONT WILL MOVE ACROSS THE AREA
SATURDAY AFTERNOON AND OVERNIGHT. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED. A LAKE THUNDERSTORM ADVISORY MAY BE
NEEDED FOR LAKE CHAMPLAIN SATURDAY AFTERNOON AND SATURDAY NIGHT.
SOUTH WINDS WILL INCREASE TO 15 TO 25 KNOTS ON SATURDAY.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.

&&

$$
SYNOPSIS...NEILES
NEAR TERM...NEILES/LOCONTO
SHORT TERM...NEILES
LONG TERM...BANACOS
AVIATION...BANACOS/LOCONTO
MARINE...NEILES



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