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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 212026
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
426 PM EDT TUE MAY 21 2013

.SYNOPSIS...
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AN ACTIVE PERIOD OF WEATHER IS EXPECTED ACROSS THE NORTH COUNTRY
THROUGH THURSDAY. A FRONT SETTLES SOUTHWARD THIS AFTERNOON...WITH
ADDITIONAL THUNDERSTORMS GENERALLY FOCUSED ACROSS SOUTH-CENTRAL
VERMONT. THE BOUNDARY WILL SHIFT BACK NORTH AS A WARM FRONT
TONIGHT INTO WEDNESDAY. THE ASSOCIATED WARM AND MOIST AIR
MASS FOR WEDNESDAY AND THURSDAY WILL BRING ADDITIONAL ROUNDS OF
THUNDERSTORMS BOTH WEDNESDAY AND THURSDAY AFTERNOON. BRIEF HEAVY
DOWNPOURS WILL BRING OVER AN INCH OF RAIN TO MOST SECTIONS OF THE
NORTH COUNTRY OVER THE NEXT 48 TO 72 HOURS. TEMPERATURES WILL
GENERALLY BE ABOVE NORMAL OVER THE NEXT SEVERAL DAYS. A COOLER AND
DRIER AIR MASS IS EXPECTED TO RETURN FOR THE UPCOMING HOLIDAY
WEEKEND.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
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AS OF 415 PM EDT TUESDAY...700MB SHORTWAVE RIDGE FLATTENS/SHIFTS
EAST OF THE AREA OVERNIGHT. IT APPEARS ANOTHER WEAK WAVE LOW WILL
DEVELOP ALONG THE FRONTAL ZONE ACROSS THE NRN GREAT LAKES ALLOWING
FOR ANOTHER SURGE OF S-SW FLOW AT 850MB ACROSS FRONTAL ZONE.
OVERALL EVOLUTION SUGGESTS INCREASE IN ISENTROPIC ASCENT WITH
INCREASING CHANCES FOR SHOWERS AND A FEW ELEVATED
TSTMS...ESPECIALLY AFTER MIDNIGHT. HAVE INDICATED MOSTLY CLOUDY TO
CLOUDY CONDITIONS....AND THE SOUTH WINDS AND CLOUDS WILL KEEP
TEMPS ON THE MILD SIDE...GENERALLY UPR 50S TO AROUND 60.
MAINTAINED SLIGHT CHANCE OF TSTM MENTION IN THE FORECAST GRIDS.
-- End Changed Discussion --

&&

.SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
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AS OF 415 PM EDT TUESDAY...NORTH COUNTRY GENERALLY IN THE WARM
SECTOR ON WEDNESDAY AS FRONTAL ZONE RETREATS BACK NORTH OF THE
INTL BORDER. DIFFICULT TO SEE MUCH IN THE WAY OF LOW-LEVEL
CONVERGENCE...AND MID-LEVEL FLOW HAS SLIGHT ANTICYCLONIC
CURVATURE. PBL DEWPOINTS DO INCREASE INTO THE LOW 60S...AND WITH
PARTIAL SUN CONDITIONS SHOULD RESULT IN SBCAPE VALUES AROUND 1000
J/KG. AGAIN...MARGINAL/WEAK FORCING IN PLAY SO WHILE POTENTIAL FOR
ORGANIZED STORMS IS LOW...ISOLD TO SCT -TSRA IS POSSIBLE...LIKELY
PEAKING WITH DAYTIME HEATING MAX IN THE MID-LATE AFTN HOURS. A FEW
STRONGER STORMS MAY PRODUCE SMALL HAIL WITH LOCALLY HEAVY
DOWNPOURS. VALLEY HIGHS ON WEDNESDAY WILL REACH THE UPR 70S TO
AROUND 80.

POSITIVE TILTED UPR TROUGH AND COLD FRONTAL ZONE APPROACHES SLOWLY
LATE WEDNESDAY NIGHT INTO THURSDAY. THIS SHOULD GENERATE A MORE
WIDESPREAD THREAT OF SHOWERS AND TSTMS BY THURSDAY AFTN. DEEP-
LAYER SWLY FLOW IN ADVANCE OF THE FRONTAL BNDRY WILL ENSURE
MOISTURE/SOME INSTABILITY ON THURSDAY...THOUGH MID-LEVEL LAPSE
RATES WILL BE RELATIVELY POOR AROUND 6 C/KM. WITH PEAK
HEATING...MAY BE SUFFICIENT FOR A SEVERE STORM OR TWO WITH GUSTY
WINDS AND MARGINALLY SVR HAIL DURING THURSDAY AFTN...ESPECIALLY
CENTRAL/S-CENTRAL VT BASED ON CURRENT INDICATIONS. HIGHS THURSDAY
WILL RANGE FROM THE MID-UPR 70S ACROSS VT TO THE UPR 60S TO NEAR
70F IN THE NRN ADIRONDACKS.

COLD FRONT WILL FINALLY CROSS THE FORECAST AREA THURSDAY
NIGHT...THOUGH UPPER LEVEL TROF AND LOW WILL TRAIL BEHIND. SLOW
MOVING FLOW CONTINUES AS SURFACE LOW SLOWLY CREEPS EASTWARD AWAY
FROM THE REGION. CHANCE FOR SHOWERS FINALLY DECREASES AT THE END
OF THE PERIOD THURSDAY NIGHT.
-- End Changed Discussion --

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 225 PM EDT TUESDAY...DEPARTING LOW PRESSURE SYSTEM WILL
HAVE POSITIVELY TILTED UPPER LEVEL TROUGH MOVE OVER THE NORTH
COUNTRY ON FRIDAY...KEEPING CHC OF SHOWERS OVER MUCH OF THE AREA.
LATE FRIDAY IN TO FRIDAY NIGHT...TROUGH LOOKS TO TILT NEUTRAL TO
NEGATIVE AS THE SFC LOW PUSHES OFF THE NEW ENGLAND COAST. SFC LOW
TRAVERSES NEWD NEAR NEWFOUNDLAND...KEEPING BACK/WRN EDGE OF
PRECIP NEAR VT...THEREFORE HAVE KEPT SLGT CHC POPS OVER VT FRIDAY
NIGHT THROUGH FIRST HALF OF SATURDAY. AS HIGH PRESSURE BUILDS
OVER SW HUDSONS BAY...EXTENDING SWD OVER THE CENTRAL GREAT
LAKES...A SHORTWAVE ROTATING ABOUT THE UPPER LEVEL LOW OVER NEW
ENGLAND WILL BE FAIRLY DRY BUT BRING CLOUDS FOR THE REST OF
SATURDAY INTO SATURDAY NIGHT. ON SUNDAY...SOME TROUGHINESS
REMAINING OVER ERN ZONES...WITH CLOUDS OVER MOST OF VT. THE SFC
HIGH PRESSURE AND SOME UPPER LEVEL RIDGING WILL TAKE HOLD OF THE
REGION FOR THE REST OF THE PERIOD.

BELOW NORMAL MAX TEMPS WILL GRADUALLY TREND WARMER THROUGHOUT THE
PERIOD WITH MIN TEMPS GENERALLY IN THE 40S.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...COMPLEX FCST AS LL MOISTURE CONTINUES
OVER MUCH OF THE AREA...WITH SOME BREAKS IN CLOUDS TO THE SOUTH
TRYING TO REACH NORTH. FRONTAL SYSTEM TO THE SOUTH ALSO HAS
INCREASING INSTABILITY ALONG IT...TRIGGERING SOME SHOWERS AND
THUNDERSTORMS WHICH SHOULD REMAIN SOUTH OF THE TAF SITES. MORE
CLOUDS MOVING IN FROM THE WEST. VRB CONDITIONS WILL PERSIST THIS
AFTN...MAINLY MVFR WITH PERIODS OF IFR CIGS. MPV AND RUT SEEING
THE MOST BREAKS IN CLOUDS AND VFR CONDITIONS...BUT MOISTURE AND
MVFR CIGS WILL REACH THESE SITES IN THE LATE AFTN TO EARLY
EVENING HRS.

MORE FOG/BR AND LOW CIGS WL BE POSSIBLE THIS EVENING ACRS TAF
SITES WITH LIGHT WINDS AND PLENTY OF LLVL MOISTURE.
ALSO...ANOTHER ROUND OF SHOWERS WITH EMBEDDED THUNDERSTORMS WL BE
POSSIBLE AFT 01Z TONIGHT...WITH MVFR TO IFR IN THE HEAVIER
SHOWERS. SHOWERS WILL TAPER OFF BY MID MORNING HOURS...WITH
GRADUALLY IMPROVING CONDITIONS.

OUTLOOK 18Z WEDNESDAY THROUGH SUNDAY...OCCASIONAL SHOWERS WITH
EMBEDDED THUNDERSTORMS WL CONT FOR WEDS INTO THURS...BEFORE SFC
HIGH PRES AND CLRING DEVELOPS BY THE WEEKEND. VFR WITH PERIODS OF
MVFR CONDITIONS IN THE HEAVIER SHOWERS/STORMS WL BE POSSIBLE. IN
ADDITION...AREAS OF FOG/BR WITH LIFR CONDITIONS WL BE POSSIBLE AT
SLK/MPV.

&&

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

&&

$$
SYNOPSIS...BANACOS/NEILES
NEAR TERM...BANACOS/NEILES
SHORT TERM...BANACOS/NEILES
LONG TERM...KGM
AVIATION...KGM