-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 240541
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
141 AM EDT FRI MAY 24 2013

.SYNOPSIS...
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE THROUGH THIS
EVENING. SOME THUNDERSTORMS WILL HAVE VERY HEAVY DOWNPOURS AND
GUSTY WINDS. LOCALIZED FLASH FLOODING IS A CONCERN AS SOME STORMS
WILL MOVE REPEATEDLY OVER THE SAME AREAS THAT HAVE ALREADY RECEIVED
COPIOUS AMOUNTS OF RAINFALL OVER THE PAST COUPLE DAYS. EXPECT MORE
RAIN FRIDAY THROUGH SUNDAY AS A NOREASTER FORMS OFF THE NEW
ENGLAND COAST. BELOW NORMAL TEMPERATURES WILL BE EXPECTED AS WELL.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
-- Changed Discussion --
AS OF 103 AM EDT FRIDAY...HEAVY RAINFALL WHICH CAUSED FLASH
FLOODING IS NOW DISSIPATING ACRS CENTRAL VT. DUAL POL RAINFALL
ESTIMATES HAVE DONE VERY WELL...WHEN COMPARING TO OBS...SHOWING A
3 TO 5 INCH PRINT FROM ESSEX CENTER/JERICHO TO UNDERHILL TO
CAMBRIDGE AREA. THIS HEAVY RAINFALL IN 1 TO 3 HOURS CAUSED
NUMEROUS ROAD WASHOUTS AND MINOR PROPERTY DAMAGE. CHECK LATEST
BTVLSR FOR FURTHER INFO.

MINOR UPDATE TO FCST TO REMOVE MENTION OF THUNDERSTORMS AND
CAPTURE CRNT TEMP/PRECIP TRENDS. SFC COLD FRNT IS ACRS THE CPV
ATTM...WITH A TRANSITION FROM A MOIST/UNSTABLE TO MUCH
COOLER/MOIST AIR MASS TAKING PLACE FROM NW TO SE. IN ADDITION...A
TIGHT THERMAL GRADIENT HAS DEVELOPMENT FROM M40S SLV TO M60S NEAR
VSF. THIS CRNT AND LLVL CAA WL HELP TO PRODUCE OCCASIONAL SHOWERS
OVERNIGHT...WITH GREATEST ADDITIONAL QPF ACRS CENTRAL/SOUTHERN VT.
ADDITIONAL RAINFALL AMOUNTS WL RANGE BTWN 0.25 AND 0.50 ACRS
SOUTHERN VT...WITH 0.10 TO 0.20 ACRS THE DACKS/CPV AND NORTHERN
AREAS. GIVEN SEVERAL HYDRO WARNINGS IN EFFECT WL CONT FLASH FLOOD
WATCH ATTM...BUT NOT ANTICIPATING ANY FURTHER FLASH FLOODING AS
THUNDERSTORMS WITH 1 TO 2 INCH PER HOUR RAINFALL RATES HAVE
DISSIPATED.

COLD FRONT MOVING THROUGH ADIRONDACKS AT THIS TIME...AND WILL BE
MAKING ITS WAY INTO CHAMPLAIN VALLEY A LITTLE AFTER MIDNIGHT.
THREAT OF THUNDERSTORMS AND HEAVY RAINFALL IN ADVANCE OF THE
FRONT...WHILE BEHIND THE FRONT PRECIPITATION MOSTLY IN THE FORM OF
LIGHT TO MODERATE RAIN SHOWERS. FLOODING ISSUES STILL
EXIST...ESPECIALLY ACROSS PARTS OF NORTHERN AND CENTRAL VERMONT
WHERE HEAVIEST RAIN HAS OCCURRED THIS EVENING. UPWARDS OF 3 INCHES
REPORTED IN SOME AREAS RESULTING IN SIGNIFICANT FLOODING.

ALSO...RAINS THIS EVENING COUPLED WITH COPIOUS RAINFALL OVER PAST
FEW DAYS HAS PROMPTED ISSUANCE OF FLOOD WARNING FOR BARTON RIVER
AT COVENTRY. WITH MORE RAIN EXPECTED OVER NEXT FEW DAYS...
POTENTIAL FOR MORE RIVER FLOODING WILL LIKELY INCREASE RIGHT INTO
THE UPCOMING WEEKEND...ESPECIALLY ACROSS NORTHERN VERMONT.

EARLIER DISCUSSION...
LAPS SOUNDING SHOW SATURATED ATMOSPHERIC COLUMNS...TALL SKINNY
CAPE VALUES OF UP TO 1300 J/KG. WARM CLOUD DEPTHS RUNNING NEAR 4KM
AND PW VALUES NEAR 1.70". BEING IN THE RIGHT ENTRANCE REGION OF
THE UPPER LEVEL JET ALL CONTINUE TO INDICATE THE THREAT OF VERY
EFFICIENT WARM PROCESSES...1 TO 3" HOUR RAINFALL TOTALS...AND
POTENTIAL FOR FLASH FLOODING. MODEL CONSENSUS SEEMS TO FAVOR TWO
SW-NE ORIENTATED AREAS, ONE IN THE WESTERN ADIRONDACKS AND ANOTHER
ACROSS SOUTH CENTRAL AND NE VT. THIS SEEMS TO BE DEVELOPING ON
RADAR. SOME AREAS HAVE HAD 2 INCHES OF RAIN ALREADY THIS WEEK SO
CONTINUED FLASH FLOOD WATCH UNTIL EARLY TOMORROW MORNING FOR MOST
OF THE NORTH COUNTRY.

FALLING TEMPERATURES CONTINUE FROM NW TO SE OVERNIGHT WITH THREAT
OF THUNDERSTORMS TAPERING OFF OVERNIGHT AS COLD FRONT PUSHES
SLOWLY SOUTH.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
AS OF 454 PM EDT THURSDAY...MODELS ARE CONSISTENT WITH THE FRONT
BECOMING NEARLY STATIONARY OVER SOUTHERN NEW ENGLAND ON FRIDAY AS
SIGNIFICANT SHORT WAVE DIVES SOUTH FROM THE GREAT LAKES TOWARD THE
MID ATLANTIC COAST WITH OVER 100M 12H HGT FALLS REACHING THE
DELMARVA AREA BY 00Z SAT THEN ROTATE NORTH TO CAPE COD BY 00Z SUNDAY.
SURFACE LOW PRESSURE DEVELOPS ALONG THE FRONT OVER SOUTHERN NEW
ENGLAND THEN WAITS FOR THE UPPER LOW TO BECOME VERTICALLY STACKED.
STRONG QG FORCING, WARM MOISTURE ADVECTION, AND STRONG LOW-MID
LEVEL FRONTOGENESIS TO COMBINE TO BRING RAIN TO THE NORTH COUNTRY.

TEMPERATURES WILL BE QUITE COLD FOR THIS TIME OF YEAR WITH
TEMPERATURES DROPPING THROUGH THE 50S IN THE VALLEYS AND INTO THE
40S IN THE MOUNTAINS ON FRIDAY. COLD TEMPERATURES WILL CONTINUE
THROUGH SATURDAY WITH LOTS OF CLOUDS AND PERIODS OF RAIN THROUGH
SATURDAY NIGHT AS UPPER LOW CUTS OFF OVER SOUTHERN NEW ENGLAND.
EXPECTING LOW TEMPERATURE MOSTLY IN THE 40S BUT SOME UPPER 30S
POSSIBLE IN THE MOUNTAINS. HAVE ALSO PUT A BIT OF WET SNOW AT THE
MOUNTAIN SUMMITS (ABOVE 2500 FT) ESPECIALLY SAT NIGHT. IT WOULD
APPEAR THAT ANOTHER 0.75-1.50" OF STEADIER LIGHT TO MODERATE RAIN
CAN BE EXPECTED THROUGH SUNDAY.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 454 PM EDT THURSDAY...UPPER LEVEL LOW PRESSURE SYSTEM WILL
BEGIN TO MOVE AWAY ON SUNDAY...HOW FAST REMAINS SOMEWHAT OF A
QUESTION. LEANED TOWARD THE EMCWF WHICH IS NOT GREAT NEWS FOR THE
THOUSANDS OF PEOPLE AROUND SUNDAY MORNING FOR THE MARATHON IN BURLINGTON.
KEPT A HIGH CHANCE OF SHOWERS GOING ON SUNDAY, HIGHEST IN THE
MORNING, BUT THERE COULD BE PERIODS WITHOUT SHOWERS AS WELL.
RIGHT NOW TEMPERATURES IN THE LOW 40S SUNDAY MORNING AND AND LOW
TO MID 50S IN THE AFTERNOON LOOK TO BE QUITE COLD FOR MAY WITH
BREEZY NORTH WINDS.

ON MONDAY THE UPPER LOW SHOULD BE MOVING FAR ENOUGH AWAY
FOR PARTLY CLOUDY TO SUNNY SKIES AND TEMPERATURES MOVING BACK INTO
THE 60S.

A SIGNIFICANT WARMING TREND WILL TAKE PLACE TUE-THU WITH
SOME CHANCE OF SHOWERS AND THUNDERSTORMS RETURNING THE FORECAST BY
WED AND THU AS TEMPERATURE BECOME MORE SUMMER-LIKE WITH RETURNING
HUMIDITY AS FLOW BECOMES SOUTHWEST WITH A BERMUDA HIGH FORMING.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
THROUGH 06Z SATURDAY...EXPECT AN EXTENDED PERIOD OF MVFR AND IFR
CONDITIONS ACROSS NORTHERN NEW YORK AND VERMONT DUE TO LOW
CEILINGS AND VISIBILITIES AS WELL AS LIGHT RAIN. THERE WILL ALSO
BE BRIEF PERIODS OF LIFR CEILINGS AS ABUNDANT LOW LEVEL MOISTURE
WILL EXIST OVER THE AREA. THE WIND WILL BECOME NORTHWEST ALL AREAS
AT SPEEDS OF 10 KNOTS OR LESS THROUGH MUCH OF THE PERIOD.

OUTLOOK 06Z SATURDAY THROUGH TUESDAY...THE COMBINATION OF A SFC
BOUNDARY AND ASSOCIATED LOW PRESSURE WILL KEEP SHOWERS IN THE TAF
SITES THRU THE WEEKEND. THESE SHOWERS WILL PRODUCE PERIODS OF MVFR
CIGS/VSBYS WITH SOME IFR CONDITIONS POSSIBLE...ESPECIALLY AT
NIGHT. IN ADDITION...BREEZY NORTHWEST WINDS WILL DEVELOP AS SFC
LOW PRES TRACKS INTO THE GULF OF MAINE ON SUNDAY. A SLOW CLEARING
TREND IS ANTICIPATED ON MONDAY...W/ VFR CONDITIONS TUESDAY.
-- End Changed Discussion --

&&

.HYDROLOGY...
AS OF 754 AM THURSDAY...FLASH FLOOD WATCH IN EFFECT UNTIL 8AM
FRIDAY FROM THE NORTHERN ADIRONDACKS EASTWARD TO THE CONNECTICUT
RIVER VALLEY. WATCH FOR MULTIPLE STORMS TO TRACK OVER THE SAME
AREA AND COMBINED WITH RAINFALL RATES AS MUCH AS 1 TO 2 INCHES PER
HOUR...FLASH FLOODING MAY RESULT. THE THREAT WILL TRANSITION ON
FRIDAY FROM FLASH FLOODING TO POTENTIAL RIVER FLOODING AS MORE
SHOWERS AND THUNDERSTORMS WILL EXIST OVER THE AREA ON FRIDAY. THE
THREAT OF RAIN WILL CONTINUE SATURDAY INTO SUNDAY...ESPECIALLY
ACROSS VERMONT. THIS SITUATION WILL HAVE TO BE MONITORED.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...FLASH FLOOD WATCH UNTIL 8 AM EDT THIS MORNING FOR VTZ001>012-
     016>019.
NY...FLASH FLOOD WATCH UNTIL 8 AM EDT THIS MORNING FOR NYZ028>031-
     034-035.

&&

$$
SYNOPSIS...SISSON
NEAR TERM...TABER
SHORT TERM...SISSON
LONG TERM...SISSON
AVIATION...EVENSON/RJS
HYDROLOGY...WFO BTV