Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 031403
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1003 AM EDT SUN MAY 3 2015

.SYNOPSIS...
A BROAD RIDGE OF HIGH PRESSURE WILL CONTINUE TO PROVIDE THE NORTH
COUNTRY WITH DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES INTO
EARLY THIS UPCOMING WEEK BEFORE COLD FRONT BRINGS SCATTERED
SHOWERS TO THE AREA. ISOLATED SHOWERS WILL BE POSSIBLE OVER THE
MOUNTAINS THIS AFTERNOON. TEMPERATURES BEHIND THE COLD FRONT WILL
DROP BACK TO NEAR NORMAL BY MIDWEEK WITH DRY CONDITIONS PREVAILING
UNTIL A WARM FRONT BRINGS A SLIGHT CHANCE OF SHOWERS TOWARDS THE
END OF THE WEEK.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
AS OF 959 AM EDT SUNDAY...FCST IN EXCELLENT SHAPE THIS MORNING
WITH ONLY MINOR UPDATE TO RELFECT CRNT OBS. STILL NOTICING A
STRONG LAKE BREEZY BOUNDARY TODAY WITH COLCHESTER REEF AT
46F...COLDER THAN THE SUMMIT OF WHITEFACE...WHILE BTV AIRPORT IS
67F. TRIED TO CAPTURE THIS MESOSCALE FEATURE IN LATEST UPDATE.
OTHERWISE...A FEW CLOUDS ASSOCIATED WITH MID LVL MOISTURE WILL
IMPACT THE CWA FROM TIME TO TIME TODAY...ALONG WITH A VERY SMALL
CHANCE OF AN ISOLATED SHOWER ACROSS SOUTHERN/CENTRAL VT. ALL IS
COVERED WELL IN CRNT FCST. EXPECTING HIGHS SIMILAR TO
YESTERDAY...MAYBE A DEGREE OR TWO WARMER.

WATER VAPOR SATELLITE IMAGERY IS SHOWING A SLIGHT INCREASE IN
AVAILABLE MOISTURE OVER THE NORTH COUNTRY THIS MORNING HOWEVER AS
WE GET THE DAYTIME VISIBLE SATELLITE THE SLIGHT INCREASE IN
MOISTURE IS NOT YET TURNING INTO INCREASED CLOUD COVER.
NONETHELESS I`VE SLIGHTLY INCREASE SKY COVER WITH A BLEND TOWARDS
THE HIRES MODELS. MOISTURE PROFILES STILL SHOW THE MAJORITY OF THE
REGION TO BE MOSTLY DRY AND ITS NOT UNTIL THE 500MB VORT COMBINES
WITH THE MOISTURE PLUME TRACKING OVER LAKE ONTARIO THAT THE
ATMOSPHERE WILL BECOME SATURATED ENOUGH TO CREATE MOSTLY CLOUDY
SKIES OVER SOUTHERN AND EASTERN VERMONT. OTHER THAN THE INCREASE
IN CLOUD COVER THE REST OF THE FORECAST IS IN PRETTY GOOD SHAPE AS
TEMPS ARE STARTING TO WARM UNDER MOSTLY SUNNY SKIES.

PREVIOUS DISCUSSION AS OF 401 AM SUNDAY...BROAD HIGH SURFACE
PRESSURE WILL BE THE THEME OF THE MORNING UNDER SOUTHERLY SURFACE
FLOW AND WESTERLY FLOW ALOFT. A RELATIVELY DRY ATMOSPHERE WILL
CONTRIBUTE TO MOSTLY CLEAR SKIES THROUGH THE EARLY MORNING BEFORE
A WEAK 500MB VORT DROPS INTO THE REGION FROM THE ONTARIO REGION.
WITH HOW DRY THE MOISTURE PROFILE IS I DONT EXPECT MANY RETURNS IN
THE FORM OF ORGANIZED SHOWER ACTIVITY. HOWEVER AS THE VORT CROSSES
THE MOUNTAINS IT WILL COLLIDE WITH THE WEAK MID LEVEL MOISTURE
CURRENTLY JUST EAST OF LAKE ERIE MOVING TOWARDS THE EAST AND
PRODUCE A FEW ISOLATED SHOWERS MAINLY EAST OF THE GREENS. THERE
COULD BE SOME LIGHTNING WITH THESE SHOWERS AS THERE WILL BE STEEP
LAPSE RATES AND SOME ELEVATE CAPE IN THE AREA. THE MAIN REASON I`M
NOT TOO BULLISH ON THE POTENTIAL REMAINS THE LACK OF AVAILABLE
MOISTURE. I EXPECT WE WILL REMAIN DRYER THAN THE MODELS ARE
FORECASTING BECAUSE A QUICK LOOK AT UP STREAM OBS SHOW THE MODELS
ARE OVERDOING THE LOW LEVEL RH AND DEWPOINTS BY A FEW DEGREES. SO
I KEPT IN THE SLIGHT CHANCE OF SHOWERS OVER SOUTHERN VERMONT BUT
AS MENTIONED BY THE PREVIOUS FORECASTER... AREAL COVERAGE WILL BE
AT BEST LIMITED.

WITH ANOTHER DAY OF HIGH PRESSURE AND SOUTHERLY RETURN FLOW WE
WILL SEE ANOTHER WARM DAY WITH 850 TEMPS BETWEEN 8-9C RESULTING IN
MAX TEMPS TODAY IN THE MID TO UPPER 70S FOR THE CHAMPLAIN AND
SAINT LAWRENCE VALLEYS AND LOWER 70S ELSEWHERE.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH TUESDAY/...
AS OF 401 AM EDT SUNDAY...OVERNIGHT THE PERIOD WE WILL SEE VERY
SIMILAR RESULTS TO SATURDAY NIGHT WITH LIGHT AND VARIABLE TO CALM
WINDS UNDER MOSTLY CLEAR SKIES ALLOWING FOR GOOD RADIATIONAL
COOLING TO DROP MIN TEMPS ACROSS THE REGION INTO THE UPPER 40S TO
LOW 50S IN THE VALLEYS. THE SURFACE HIGH PRESSURE WILL STILL BE
FIRMLY ENTRENCHED MONDAY MORNING AND THUS WE WILL CONTINUE TO SEE
ANOTHER DAY OF ABOVE AVERAGE TEMPS LIKELY BEING THE WARMEST DAY OF
THE SEASON THUS FAR. MAX TEMPS WILL APPROACH 80 DEGREES IN THE
CHAMPLAIN VALLEY AND UPPER 70S AREA WIDE. THAT WILL SOON SUBSIDE
THOUGH AS A COLD FRONT LOOKS PRIMED TO DROP SOUTH FROM QUEBEC
BRINGING A SCATTERED CHANCE OF SHOWERS ACROSS THE AREA. THE
COVERAGE OF THE SHOWERS REMAINS A BIT OF A QUESTION AS THE LARGER
GLOBAL MODELS BRING A WIDESPREAD PATH OF SHOWERS HOWEVER THE
SMALLER HIGHER RESOLUTION MODELS SHOW A LINE THAT FALTERS AS IT
MOVES INTO THE HIGHER TERRAIN OF THE ADIRONDACKS. AS SUCH I
BLENDED BOTH COMING UP WITH MORE OF A 40-60% CHANCE IN THE HIGHER
TERRAIN WITH A 20-30% CHANCE IN THE CHAMPLAIN VALLEY. THE
CONSENSUS OF ALL THE GUIDANCE IS THAT THE HIGHER TERRAIN
DEFINITELY DOES HAVE THE BEST CHANCE TO SEE THE MOST RAINFALL.
CURRENT QPF TOTALS SEE ABOUT ABOUT 0.10" TO 0.25" ACROSS MOST OF
THE AREA WITH THE HIGHEST TOTALS IN THE HIGHER TERRAIN OF THE
ADIRONDACKS BEFORE THE LINE POTENTIALLY DISSIPATES.

THE OTHER IMPORTANT FEATURE IS THAT THE STEEP LAPSE RATES LEADING
UP TO THE COLD FRONT WILL LIKELY BRING SOME STRONG GUSTY WINDS.
THAT WILL COMBINE WITH AREAS OF LOW RH`S HOWEVER THE OVERLAP OF
LOW RH`S AND GUSTY WINDS LOOKS TO BE MARGINAL SO I`M NOT READY TO
ISSUE A FIRE WEATHER WATCH AS OF THIS FORECAST PACKAGE.

THEN TUESDAY BEHIND THE FRONT MORE SEASONABLE TEMPERATURES WILL
RETURN TO THE AREA SEEING TEMPS OVERNIGHT WILL BE IN THE IN THE
MID TO LOW 50S WARMING TO THE MID 60S ACROSS THE AREA DURING THE
AFTERNOON.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 356 AM EDT SUNDAY...DRY AND SPRING-LIKE WEATHER EXPECTED
THROUGH THURSDAY NIGHT.

ECMWF AND GFS MODELS IN GOOD AGREEMENT THROUGH THE PERIOD.
THUS...FORECASTER CONFIDENCE IS HIGH.

ECMWF AND GFS MODELS SHOW A RIDGE OF HIGH PRESSURE WILL BUILD INTO
THE REGION ON TUESDAY NIGHT AND REMAIN THROUGH THURSDAY NIGHT. ON
FRIDAY...BOTH THE ECMWF AND GFS MODELS SHOWING A WARM FRONT WILL
BUILD SOUTHEAST FROM CANADA INTO THE REGION ON FRIDAY...SO HAVE GONE
WITH SLIGHT CHANCE POPS FOR RAIN SHOWERS ON FRIDAY.

A COLD FRONT WILL MOVE SOUTH FROM CANADA FRIDAY NIGHT AND
SATURDAY...SO HAVE GONE WITH CHANCE POPS FOR SHOWERS AND
THUNDERSTORMS.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
THROUGH 12Z MONDAY...VFR CONDITIONS EXPECTED THROUGH THE PERIOD
AS A WEAK RIDGE OF HIGH PRESSURE WILL BE OVER THE REGION.
EXPECTING SOME CUMULUS CLOUDS TO DEVELOP ACROSS THE REGION TODAY
BETWEEN 13Z-15Z...AS MODEL GUIDANCE AGAIN SHOWING STEEP LOW LEVEL
LAPSE RATES ACROSS THE REGION TODAY. EXPECTING MAINLY CLEAR SKIES
AFTER 00Z MONDAY.

OUTLOOK 12Z MONDAY THROUGH THURSDAY...

12Z MONDAY-00Z TUESDAY...VFR CONDITIONS WITH WEAK HIGH PRESSURE
OVER THE REGION.

00Z TUESDAY-12Z TUESDAY...MAINLY VFR BUT WITH AREAS OF MVFR/IFR
IN SHOWERS AS A WEAK COLD FRONT MOVES THROUGH THE REGION.

12Z TUESDAY-00Z FRIDAY...VFR CONDITIONS DEVELOP ONCE AGAIN WITH
WEAK SURFACE HIGH PRESSURE AREA BUILDING INTO THE REGION THROUGH
THE PERIOD.

&&

.FIRE WEATHER...
THE 60 TO 90 DAY DEPARTURE FROM NORMAL PRECIPITATION SHOWS A
DEFICIT OF 2 TO 4 INCHES ACROSS MOST OF NORTHERN NY INTO VERMONT.
DRY CONDITIONS CONTINUE ACROSS OUR REGION WITH ONLY A 10 TO 20%
CHANCE OF AN ISOLATED SHOWER ON SUNDAY AFTERNOON ACROSS CENTRAL
AND SOUTHERN VT. ANY PRECIPITATION TODAY WILL BE VERY LIGHT. A
COLD FRONT APPROACHING THE REGION FROM SOUTHERN CANADA WILL
INCREASE THE WINDS ON MONDAY AFTERNOON WITH BREEZY SOUTH TO
SOUTHWEST WINDS OF 10 TO 20 MPH WITH GUSTS BETWEEN 25 AND 35 MPH
EXPECTED. THE STRONGEST WINDS WILL BE ACROSS THE SAINT LAWRENCE
VALLEY...CHAMPLAIN VALLEY...AND EXPOSED HIGHER TERRAIN OF CENTRAL
AND NORTHERN VERMONT. MEANWHILE...MINIMUM RELATIVE HUMIDITIES
VALUES WILL DROP BETWEEN 26% AND 35% BETWEEN NOON AND 4 PM ON
MONDAY...BEFORE DEEPER MOISTURE ARRIVES ASSOCIATED WITH THE COLD
FRONT. IF THE COLD FRONT ARRIVES EARLIER THAN EXPECTED...THAN RH
VALUES WILL BE HIGHER ESPECIALLY ACROSS THE NORTHERN VT AND NY.
THE LOWEST RH VALUES WILL BE ACROSS CENTRAL AND SOUTHERN VT ON
MONDAY. THESE CONDITIONS COMBINED WITH VERY DRY FINE FUELS BELOW
2000 FEET AND LIMITED AREAS OF GREEN UP PER COORDINATION WITH OUR
FIRE USERS...SUPPORTS THE POTENTIAL FOR FIRE WEATHER HEADLINES ON
MONDAY AFTERNOON...IF CURRENT TRENDS CONTINUE. STILL SOME
UNCERTAINTY ON MIN RH`S...TIMING OF CLOUDS/PRECIPITATION
ASSOCIATED WITH COLD FRONT AND MAGNITUDE OF WIND SPEEDS.

&&

.MARINE...
WITH WARMING TEMPERATURES THIS WEEKEND ITS IMPORTANT TO REMEMBER
THAT THE LAKE AND RIVER WATERS ARE STILL QUITE COLD. BELOW IS A
REMINDER ABOUT COLD WATER SAFETY.

EARLY IN THE BOATING SEASON...WATER TEMPERATURES ON RIVERS...PONDS
AND LAKES REMAIN RATHER COLD. IMMERSION IN COLD WATER CAN BE LIFE
THREATENING VERY QUICKLY DUE TO HYPOTHERMIA AND THE BODIES INABILITY
TO WORK EFFICIENTLY IN THE COLD WATER. THEREFORE...IT IS RECOMMENDED
TO CONSIDER POSTPONING SMALL CRAFT BOATING ACTIVITIES UNTIL WATER
TEMPERATURES BECOME WARMER. HOWEVER...IF YOU CHOOSE TO VENTURE
OUT...WEAR ALL RECOMMENDED COLD WATER PROTECTIVE GEAR...INCLUDING
A LIFE JACKET...IN THE EVENT OF AN ACCIDENT.

&&

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

&&

$$
SYNOPSIS...DEAL
NEAR TERM...DEAL/TABER
SHORT TERM...DEAL
LONG TERM...WGH
AVIATION...WGH
FIRE WEATHER...TABER
MARINE...WFO BTV



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