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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 151744
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
144 PM EDT WED MAY 15 2013

.SYNOPSIS...
HIGH PRESSURE SLIDES EASTWARD INTO THE GULF OF MAINE TODAY
ALLOWING BREEZY SOUTH WINDS TO DEVELOP. AN APPROACHING FRONTAL
SYSTEM FROM THE WEST WILL BRING SCATTERED SHOWERS DURING THE LATE
AFTERNOON AND INTO TONIGHT...WITH RAINFALL AMOUNTS GENERALLY LESS
THAN A QUARTER INCH. SCATTERED LIGHT RAIN SHOWERS ARE EXPECTED AGAIN
ON THURSDAY WITH GUSTY WEST WINDS. TEMPERATURES WILL TREND WARMER
AND CLOSER TO MID-MAY AVERAGES OVER THE NEXT SEVERAL DAYS.

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 1225 PM EDT WEDNESDAY...HAVE ADDED MENTION OF THUNDERSTORMS
ACROSS ST. LAWRENCE AND FRANKLIN COUNTIES NEXT SEVERAL HOURS BASED
ON MUCAPE VALUES OF 250-500 J/KG AND SEVERAL CG/S NEAR THE ST.
LAWRENCE RIVER PER NLDN DATA. REMAINDER OF THE FORECAST IS
UNCHANGED THIS AFTN AND EVENING.

PREVIOUS DISCUSSION...SFC RIDGE HAS SLID INTO THE GULF OF MAINE
AND GUSTY SOUTH WINDS HAVE DEVELOPED IN ADVANCE OF APPROACHING
WARM FRONTAL ZONE. WINDS OF 15-25 MPH WITH GUSTS TO 35 MPH ARE
EXPECTED IN THE CHAMPLAIN VALLEY THROUGH THE AFTN HOURS. A LAKE
WIND ADVISORY CONTINUES ON LAKE CHAMPLAIN.

COMPOSITE REFLECTIVITY IMAGERY SHOWS SEVERAL BANDS OF SHOWER
ACTIVITY ACROSS CENTRAL NY NWD INTO ST. LAWRENCE COUNTY AT 1430Z
ASSOCIATED WITH WARM FRONT. THERE HAVE BEEN A FEW TSTMS ON THE
WRN EDGE OF THE FRONTAL RAIN BAND ASSOCIATED WITH ELEVATED CAPE
AND STEEP MID-LEVEL LAPSE RATES ON LEADING EDGE OF RESIDUAL
ELEVATED MIXED LAYER. A FEW TSTMS MAY REACH ST. LAWRENCE INTO
FRANKLIN COUNTIES EARLY THIS AFTN. OTHERWISE...CONTINUING WITH THE
IDEA OF SCATTERED SHOWER ACTIVITY SHIFTING ESEWD ACROSS OUR FORECAST
AREA DURING THE MID-LATE AFTN AND INTO THE EARLY EVENING HOURS.
HIGH TEMPERATURES THIS AFTERNOON GENERALLY IN THE MID 60S.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/...
AS OF 457 AM EDT WEDNESDAY...PRECIPITATION ASSOCIATED WITH WARM AIR
ADVECTION WILL BE ENDING THIS EVENING...BUT STILL CHANCE SOME
SHOWERS THROUGH AROUND MIDNIGHT AS OCCLUDED FRONT MAKES ITS WAY
ACROSS THE REGION. TOTAL PRECIPITATION THROUGH TONIGHT GENERALLY A
QUARTER INCH OR LESS. VERY LIGHT AMOUNTS EXPECTED IN THE CHAMPLAIN
VALLEY DUE SOME SHADOWING FROM ADIRONDACKS DUE SOUTHWESTERLY 850MB
FLOW. MAINLY DRY AFTER MIDNIGHT WITH SOME PARTIAL CLEARING. GUSTY
SOUTH WINDS THIS EVENING WILL BECOME MORE WESTERLY OVERNIGHT AND
DIMINISH. MIN TEMPS NOT ALL THAT COOL...WITH LOWS MAINLY IN THE 40S.

CLOSED UPPER LOW ALONG WITH ITS ASSOCIATED SURFACE FEATURE WILL MAKE
THEIR AWAY ACROSS SOUTHERN QUEBEC DURING THURSDAY. SECONDARY COLD
FRONT WILL MOVE ACROSS FORECAST AREA DURING THE DAY AS WELL. STEEP
LAPSE RATES DEVELOP DURING THE DAY ALLOWING FOR ANOTHER PERIOD OF
BRISK WESTERLY WINDS OF 15-25 MPH WITH GUSTS 35 MPH POSSIBLE.
EXPECT VARIABLE AMOUNTS OF CLOUDS WITH SCATTERED INSTABILITY DRIVEN
SHOWERS BY AFTERNOON...WITH GREATEST CHANCE BEING OVER THE NORTHERN
MOUNTAINS. TEMPS SLIGHTLY ABOVE NORMAL WITH VALLEY HIGHS IN THE
UPPER 60S.

DECREASING CHANCES FOR SHOWERS THURSDAY NIGHT WITH SOME CLEARING.
IT WILL BE A BIT COOLER WITH LOWS IN THE UPPER 30S TO MID 40S.
LITTLE CHANGE ON FRIDAY AS NORTHWEST FLOW REGIME CONTINUES.
WEAK DISTURBANCES IN THE FLOW ALOFT WILL RESULT IN SOME CLOUDINESS
AND CHANCE OF A FEW SHOWERS ONCE AGAIN OVER NORTHERN AREAS.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 352 AM EDT WEDNESDAY...EXTENDED FORECAST REMAINS LARGELY
UNCHANGED AS MEDIUM RANGE MODELS CONTINUE TO HIGHLIGHT MAINLY DRY
CONDITIONS UNDER SURFACE HIGH PRESSURE AND UPPER RIDGING THROUGH
MUCH OF THE PERIOD. UPPER TROUGH OVER THE NOVA SCOTIA AND
NEWFOUNDLAND AREA FRIDAY NIGHT WILL SLOWLY SHIFT OFF THE EASTERN
SEABOARD THROUGH THE WEEKEND AS UPPER LEVEL RIDGING OVER THE
CENTRAL CONUS SHIFTS EASTWARD INTO THE NORTHEAST. FARTHER WEST A
BROAD UPPER TROUGH SETTLES OVER THE WESTERN CONUS SETTING UP A
NICE OMEGA BLOCK PATTERN ACROSS THE EASTERN US. OTHER THAN A FEW
LINGERING SHOWERS POSSIBLE FRIDAY NIGHT UNDER EXITING NORTHWEST
FLOW...THE BTV CWA WILL GENERALLY EXPERIENCE PARTLY CLOUDY AND
DRY CONDITIONS SATURDAY THROUGH MONDAY ALONG WITH NEAR NORMAL
TEMPERATURES WITH HIGHS IN THE UPPER 60S TO LOWER 70S...AND LOWS
IN THE MID 40S TO LOWER 50S. OUR NEXT CHANCE FOR PRECIP WILL COME
TUESDAY THROUGH THROUGH WEDNESDAY (AND POSSIBLY LONGER) AS THE
BLOCKING PATTERN BEGINS TO SLOWLY BREAK DOWN AND MOIST
SOUTHWESTERLY FLOW DEVELOPS AS THE WESTERN TROUGH SHIFTS
EASTWARD. COULD END UP BEING A FAIRLY WET FEW DAYS NEXT WEEK AS
THE PATTERN IS VERY SLOW TO BREAK DOWN...BUT CERTAINLY IS TOO FAR
OUT TO HANG YOUR HAT ON ANY REAL SOLUTION. FOR NOW...WILL
INTRODUCE SOME LOW CHANCE POPS TO THE FORECAST. TEMPS
TUESDAY/WEDNESDAY SHOULD WARM SLIGHTLY UNDER SOUTHWEST FLOW WITH
HIGHS IN THE 70S...AND VERY MILD LOWS IN THE UPPER 50S TO 60S
POSSIBLE.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
THROUGH 18Z THURSDAY...AVIATION CHALLENGE THRU THIS AFTN WL BE
-SHRA AND POTENTIAL IMPACTS ON TAF SITES/GUSTY WINDS...FOLLOWED BY
POTENT MVFR CIGS AT SLK/MPV THIS EVENING. CRNT RADAR SHOWS A
BROKEN LINE OF -SHRA MOVING INTO THE CPV ATTM...WITH SOME
LIGHTNING ACTIVITY NOTED ACRS THE SLV. THESE SHOWERS ARE
ASSOCIATED WITH A WARM FRONT AND SOME WEAK ELEVATED INSTABILITY.
DUE TO VERY DRY CONDITIONS NEAR THE SFC...EXPECT LEADING EDGE OF
PRECIP TO FALL AS VIRGA WITH CIGS BTWN 5000 AND 8000 FEET.
HOWEVER...LLVLS WL SATURATE ENOUGH TO PRODUCE A BRIEF 1 TO 2 HOUR
WINDOW OF -SHRA AT OUR TAF SITES THIS AFTN...WITH MAINLY VFR
CONDITIONS...WITH POTENTIAL OF A BRIEF 15 TO 30 MINUTES OF MVFR AT
SLK/MPV. SHOWERS WL QUICKLY SHIFT EAST OF TAF SITES BY 22Z THIS
EVENING...WITH SOME GUIDANCE SHOWING THE POTENTIAL FOR MVFR
CIGS...ESPECIALLY AT MPV/SLK. WL MENTION INTO TEMPO GROUP BTWN
00Z-04Z TONIGHT FOR MVFR CIGS. FINALLY...GUSTY SOUTH WINDS AT 15
TO 30 KNTS WL PREVAIL BEFORE THE SHOWERS ARRIVE THIS AFTN...BECOME
LIGHTER WHEN THE RAIN IS FALLING...THEN SHIFT TO THE SOUTHWEST AND
INCREASE AGAIN AT 10 TO 20 KNOTS THIS EVENING...BEFORE DECREASING
UNDER 10 KNTS BY 05Z.

OUTLOOK 18Z THURSDAY THROUGH MONDAY...
A WEAK S/W WL PRODUCE ISOLATED/SCATTERED SHOWERS ACRS OUR
CENTRAL/NORTHERN TAF SITES BTWN 18Z-22Z THURS...WITH A BRIEF
PERIOD OF MVFR POSSIBLE AT MPV/SLK. OTHERWISE...SFC HIGH PRES AND
VFR CONDITIONS WL PREVAIL THRU THE WEEKEND. HOWEVER...AS INSTABILITY
INCREASES ON SUNDAY...A FEW AFTN/EVENING SHOWERS WL BE
POSSIBLE...ALONG WITH A BRIEF PERIOD OF MVFR.
-- End Changed Discussion --

&&

.MARINE...
LAKE WIND ADVISORY HAS BEEN ISSUED. GRADIENT TIGHTENS ACROSS THE
REGION TODAY IN ADVANCE OF A WARM FRONT. EXPECT SOUTH WINDS TO
INCREASE TO 15 TO 25 KNOTS THIS MORNING AND TO 25 TO 35 KNOTS THIS
AFTERNOON AND EVENING. WINDS WILL DIMINISH OVERNIGHT WITH PASSAGE
OF FRONTAL SYSTEM. WAVES LATER TODAY INTO EARLY TONIGHT MAY REACH
AS HIGH AS 4 TO 6 FEET ON THE BROAD LAKE BEFORE SUBSIDING OVERNIGHT.

&&

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

&&

$$
SYNOPSIS...RJS
NEAR TERM...BANACOS/RJS
SHORT TERM...RJS
LONG TERM...LAHIFF
AVIATION...TABER
MARINE...