Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 301413
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1013 AM EDT SAT MAY 30 2015

.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL PRODUCE OCCASIONAL
SHOWERS AND THUNDERSTORMS THIS AFTERNOON ACROSS THE NORTH COUNTRY.
LOCALIZED HEAVY DOWN POURS...FREQUENT LIGHTNING...AND GUSTY WINDS
WILL BE POSSIBLE WITH ANY THUNDERSTORMS. A WIDESPREAD RAINFALL IS
EXPECTED TONIGHT INTO SUNDAY...WITH ADDITIONAL SHOWERS ON MONDAY.
TEMPERATURES WILL WARM BACK INTO THE 70S AND 80S TODAY...WITH BREEZY
SOUTH WINDS...BUT A COOLER AND WETTER PATTERN DEVELOPS FOR SUNDAY
INTO EARLY THIS UPCOMING WEEK.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
AS OF 956 AM EDT SATURDAY...FORECAST REMAINS ON TRACK WITH
SCATTERED CONVECTIVE STORMS MID AFTERNOON THRU EARLY EVENING WITH
HEAVY DOWNPOURS AND LOCALIZED DAMAGING WINDS POSSIBLE. MAINLY 3-5
PM ACROSS NRN NY AND 4-7PM ACROSS WRN/CENTRAL VT FOR STRONGEST
T-STORM THREAT.

SYNOPSIS: NORTH COUNTRY IS EMBEDDED WITHIN WARM/HUMID LOW-LEVEL AIR
MASS WITH MODERATELY STRONG SOUTHERLY TO SOUTHWESTERLY GRADIENT
FLOW IN PLACE (BETWEEN SURFACE ANTICYCLONE EAST OF NEW ENGLAND AND
STRONG FRONTAL BNDRY ACROSS SWRN QUEBEC INTO SERN ONTARIO).
SATELLITE IMAGERY SHOWS MID-LEVEL CLOUDS GRADUALLY ERODING AT
1330Z...AND AREAS WITH FULL SUN IN THE ST. LAWRENCE VALLEY ALREADY
CLIMBING INTO THE LOWER 80S AT 14Z WITH SFC DEWPOINTS IN THE LOW
TO MID 60S. EXPECTATION BASED ON BTV-4KM WRF AND NCAR 3KM WRF
ENSEMBLE IS FOR MULTICELLULAR CONVECTION TO DEVELOP ACROSS CENTRAL
NY AND SPREAD NEWD ACROSS NRN NY BY MID-AFTERNOON. GENERALLY
LOOKING AT SBCAPE VALUES BETWEEN 1000-2000 J/KG AREAWIDE WITH
LITTLE OR NO CIN ACROSS NRN NY INTO THE CHAMPLAIN VALLEY BY 18Z.
FORCING IS NOT PARTICULARLY STRONG, WITH BETTER CONVERGENCE TO OUR
NW ALONG THE FRONTAL ZONE. DEEP-LAYER SHEAR AND MID- LEVEL LAPSE
RATES ARE MARGINAL FOR ORGANIZED SVR THREAT...BUT AMPLE LOW-LEVEL
BULK SHEAR WITH 850MB LOW-LEVEL JET AND STEEP SFC BASED LAPSE
RATES (FROM INSOLATIONAL HEATING) WILL RESULT IN SOME ROBUST
UPDRAFTS THIS AFTERNOON. LOCALIZED DAMAGING WINDS REMAIN POSSIBLE
WITH A FEW STRONGER CORES/DOWNDRAFTS. WITH PW VALUES 1.75-1.90"
...ALSO MAINTAINED MENTION OF LOCALLY HEAVY DOWNPOURS WITH
T-STORMS. SOME BACKBULIDING POSSIBLE WITH CORFIDI VECTORS LESS
THAN 5 KTS...SO WILL NEED TO MONITOR FOR TRAINING CELLS (THOUGH
ANTECEDENT CONDITIONS ARE RELATIVELY DRY FOR ANY RIVER
CONCERNS...MAIN ISSUE WOULD BE POOR DRAINAGE FLOODING OR RAPID
RISES ON STREAMS IN STEEPER TERRAIN AREAS. LOCALIZED HEAVY
RAINFALL IS POSSIBLE WITH ANY STORM. THINKING WIDESPREAD RAINFALL
OF 0.50 TO 1.50 WITH LOCALIZED AMOUNTS NEAR 3.0" POSSIBLE. SOME
MINOR POOR DRAINAGE/URBAN FLOODING IS POSSIBLE ASSOCIATED WITH THE
HIGHER RAINFALL RATES. SOUTH TO SW WINDS WILL REMAIN 15-25 MPH
WITH GUSTS 30-35 MPH (HIGHEST IN THE CHAMPLAIN VALLEY AND ST.
LAWRENCE VALLEY) THROUGH MID AFTERNOON. FRONTAL BNDRY ARRIVES IN
THE ST. LAWRENCE VALLEY BY 02-03Z...WITH NWLY WIND SHIFT AT THAT
TIME.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH MONDAY/...
AS OF 330 AM EDT SATURDAY...SHOWERS AND ISOLATED THUNDERSTORMS
WILL QUICKLY DECREASE IN AREAL COVERAGE AND INTENSITY AFT
04Z...WITH MAINLY LIGHT STRATO FORM RAIN LIKELY. SFC BOUNDARY IS
EXPECTED TO BECOME STATIONARY ALONG THE MID ATLANTIC
STATES/SOUTHERN NEW ENGLAND ON SUNDAY...WHILE ADDITIONAL
ENERGY/MOISTURE NOW OVER THE MS RIVER VALLEY STREAMS INTO OUR
REGION. THIS POTENT S/W ENERGY AND ASSOCIATED MID/UPPER LVL TROF
WILL HELP TO DEVELOP SFC LOW PRES...WHICH WILL TRAVEL ALONG THE
BOUNDARY AND ENHANCE RAINFALL ACRS OUR REGION ON SUNDAY AFTN INTO
MONDAY. BOTH GFS/NAM SHOW IMPRESSIVE NOSE OF 85H JET OF 40 TO 50
KNOTS LIFTING ACRS CENTRAL NY ON SUNDAY EVENING...ALONG WITH GOOD
DEEP LAYER THETA E ADVECTION...AND RRQ OF 25H JET. THIS MOISTURE
AND STRONG LIFT WILL PRODUCE ANOTHER ROUND OF MODERATE TO HEAVY
RAINFALL. GIVEN THE LACK OF INSTABILITY PER SOUNDINGS...AS WE ARE
ON THE COLD SIDE OF FRONT...WITH JUST SOME WEAK ELEVATED
INSTABILITY...NOT EXPECTING EXTREME RAINFALL RATES. HOWEVER...IF
BOUNDARY LIFTS FURTHER NORTH THAN EXPECTED...SOME HIGHER PRECIP
RATES WILL BE POSSIBLE. GIVEN THE AVAILABLE MOISTURE AND EXPECTED
LIFT...ANOTHER WIDESPREAD 1 TO 2 INCHES OF RAINFALL IS POSSIBLE
SUNDAY NIGHT INTO MONDAY. THIS WILL CAUSE SOME ADDITIONAL RISES ON
LOCAL STREAMS AND RIVERS...BUT ONCE AGAIN NOT EXPECTING ANY LARGE
STEM RIVER FLOODING. TEMPS WILL BE BELOW NORMAL ON SUNDAY AND
MONDAY WITH HIGHS GENERALLY IN THE 50S/60S AND LOWS IN THE 40S TO
MID 50S. GIVEN CLOUDS AND PRECIP...AND NORTH WINDS THE DIURNAL
CHANGE WILL BE LIMITED.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 415 AM EDT SATURDAY...RAIN THREAT CONTINUES MONDAY NIGHT INTO
TUESDAY. WEAK SURFACE LOW PASSING JUST SOUTH OF NEW ENGLAND...
WITH TROUGH EXTENDING NORTH OF THE LOW INTO FORECAST AREA.
MEANWHILE...RATHER VIGOROUS UPPER LOW WILL BE TRACKING FROM GREAT
LAKES MONDAY NIGHT INTO FORECAST AREA DURING TUESDAY. CHANCES FOR
RAINFALL EXPECTED TO BE HIGHEST OVER VERMONT...WHERE SOME
ADDITIONAL HEAVY RAINFALL POSSIBLE. THIS IS ESPECIALLY TRUE IF
ECMWF IS CORRECT...WHICH IS SLOWER WITH EASTWARD SHIFT OF THE
SURFACE FEATURE AND THE HIGHER PRECIPITABLE WATER VALUES. IT WILL
REMAIN COOL ON TUESDAY WITH THE WET WEATHER AND CLOUDS...WITH
HIGHS IN THE UPPER 50S TO MID 60S.

UPPER LOW MAKES ITS WAY EAST ACROSS THE REGION TUESDAY NIGHT AND
THEN HEADS INTO EASTERN CANADA WEDNESDAY. CHANCE OF SHOWERS
CONTINUES TUESDAY NIGHT...BUT DRIER CONDITIONS RETURN FOR WEDNESDAY
AS HEIGHTS RISE WITH DEPARTURE OF UPPER LOW WHILE SURFACE HIGH
PRESSURE BUILDS INTO THE REGION. LARGE AREA OF HIGH PRESSURE THEN
EXPECTED TO PREVAIL FOR THURSDAY AND FRIDAY. AIRMASS WARMING WITH
TIME...SO LOOK FOR TEMPERATURES TO RETURN TO ABOVE NORMAL READINGS
LATER IN THE WEEK WITH HIGHS IN THE UPPER 70S AND LOWER 80S.
NIGHTTIME LOWS WILL RANGE MOSTLY FROM THE MID 40S TO MID 50S.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 12Z SUNDAY...VFR FOR MUCH OF TODAY WITH CONDITIONS TRENDING
MVFR LATER TODAY INTO TONIGHT ALONG WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS. OTHER AVIATION CONCERN WILL BE GUSTY
SOUTHERLY WINDS TODAY.

BROKEN MID DECK OF CLOUDS ACROSS THE FORECAST AREA EARLY THIS
MORNING. EXPECT INCREASING CLOUDS TODAY WITH GRADUALLY LOWERING
CEILINGS IN ADVANCE OF A COLD FRONT. STRENGTHENING GRADIENT AHEAD
OF THE FRONT WILL ALLOW FOR SOUTHERLY WINDS TO INCREASE INTO THE
12-18 KT RANGE WITH GUSTS 25-30 KTS. SHOWER/THUNDERSTORM COVERAGE
WILL INCREASE AFTER 18Z ACROSS NORTHERN NEW YORK AND AFTER 21Z
ACROSS VERMONT. SOME STORMS COULD TURN STRONG WITH GUSTY OUTFLOW
WINDS...LIGHTNING AND REDUCED VISIBILITY IN HEAVY DOWNPOURS. HAVE
INDICATED SHOWERS WITH ABOUT A 4 HOUR PERIOD WITH THE A MENTION
OF VCTS.

OUTLOOK 12Z SUNDAY THROUGH WEDNESDAY...
PERIODS OF RAIN WITH MVFR CONDITIONS SUNDAY INTO TUESDAY WITH
STALLED FRONT SOUTH OF THE AREA. IMPROVING WEATHER TUESDAY NIGHT
INTO WEDNESDAY WITH VFR CONDITIONS EXPECTED.

&&

.MARINE...
AS OF 700 AM EDT SATURDAY...A LAKE WIND ADVISORY IS IN EFFECT.
SOUTH WINDS WILL BE INCREASING TO 15 TO 25 KTS THIS MORNING...AND
MAY REACH 30 KTS ON THE BROAD LAKE THIS AFTERNOON INTO THE EVENING
HOURS. THIS DUE TO TIGHTENING PRESSURE GRADIENT IN ADVANCE OF
APPROACHING COLD FRONT. WITH PASSAGE OF THE FRONT TONIGHT...WINDS
WILL SHIFT INTO THE WEST AND DIMINISH A BIT TO 15 TO 20 KTS. WAVE
HEIGHTS WILL BUILD TO 2 TO 4 FEET THIS AFTERNOON. THE THREAT OF
SHOWERS AND THUNDERSTORMS WILL BE INCREASING THIS AFTERNOON AND
EVENING AS WELL...WITH SHIFTING WINDS...HEAVY DOWNPOURS AND
DANGEROUS LIGHTNING POSSIBLE IN ANY THUNDERSTORMS.

&&

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

&&

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



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