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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 231134
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
734 AM EDT THU MAY 23 2013

.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL BECOME WIDESPREAD ACROSS THE NORTH
COUNTRY THIS AFTERNOON AND TONIGHT. VERY HEAVY DOWNPOURS AND GUSTY
WINDS WILL EXIST WITH THE THUNDERSTORMS...AND FLASH FLOODING WILL
BE A CONCERN AS STORMS WILL MOVE IN SUCH A WAY AS TO INCREASE
RAINFALL AMOUNTS IN A SMALL AREA AND HELP TO CAUSE FLASH FLOODING.
EXPECT MORE PRECIPITATION FRIDAY AND SATURDAY AS AN UPPER LEVEL
LOW PRESSURE SYSTEM DEVELOPS OVER NEW ENGLAND. BELOW NORMAL
TEMPERATURES WILL BE EXPECTED AS WELL.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 415 AM EDT THURSDAY...JUST DEALING WITH SOME SCATTERED
SHOWERS THIS MORNING...ESPECIALLY OVER NORTHERN NEW YORK WHERE
BETTER DYNAMIC SUPPORT EXISTS AHEAD OF APPROACHING UPPER TROUGH.
HOWEVER...THE CONVECTIVE THREAT WILL INCREASE THIS AFTERNOON AND
EVENING AS SUFFICIENT INSTABILITY DEVELOPS FROM THE NORTHERN
ADIRONDACKS EASTWARD TO THE CONNECTICUT RIVER VALLEY AHEAD OF
APPROACHING UPPER TROUGH. HIGH PRECIPITABLE WATER VALUES EXIST
OVER THE AREA...THUS HEAVY DOWNPOURS WILL EXIST WITH THE
THUNDERSTORMS AND MORE IMPORTANTLY...THE FLOW PATTERN WILL BE
CONDUCIVE FOR THE TRAINING OF CELLS. THIS COMBINED WITH RAINFALL
RATES OF 1 TO 2 INCHES PER HOUR SUGGESTS THE POTENTIAL FOR FLASH
FLOODING WILL EXIST. WILL BE ISSUING A FLASH FLOOD WATCH AS A
RESULT FROM THE NORTHERN ADIRONDACKS EASTWARD TO THE CONNECTICUT
RIVER VALLEY. WATCH WILL RUN FROM NOON TODAY THROUGH 8AM FRIDAY.
ISOLATED FLASH FLOODING EXISTED ON WEDNESDAY ACROSS THE AREA...BUT
IN THIS CASE THE AREAL COVERAGE OF STORMS SUGGESTS MORE AREAS
COULD BE AFFECTED BY FLASH FLOODING. ONE LAST ITEM THAT WILL EXIST
IS SOME OF THE STORMS MAY ALSO PRODUCE GUSTY WINDS AND WILL
INCLUDE THIS WORDING IN THE FORECAST AS WELL.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH SATURDAY/...
AS OF 415 AM EDT THURSDAY...POTENTIAL FOR FLASH FLOODING WILL
EXIST THROUGH 12Z FRIDAY WITH TONIGHT BEING FAVORABLE FOR
WIDESPREAD SHOWERS AND THUNDERSTORMS. HIGH PRECIPITABLE WATER AIR
REMAINS OVER THE AREA AND THE TRAINING OF CELLS OVER THE SAME AREA
WILL HELP KEEP THE THREAT OF FLASH FLOODING GOING TONIGHT. CAN
EASILY SEE 1 TO 2 INCH RAINFALL RATES AN HOUR THAT COULD EASILY
CAUSE PROBLEMS. IT LOOKS LIKE THE HYDROLOGIC CONCERNS WILL SHIFT
FROM FLASH FLOODING EARLY FRIDAY TO POTENTIAL FLOODING ON RIVERS.
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL WANT TO BECOME CUT OFF
OVER THE AREA ON FRIDAY AND SATURDAY...WHICH WILL HELP KEEP
SHOWERS AND SOME STORMS OVER THE AREA DURING THIS PERIOD AND
CONTINUE TO POTENTIALLY PRODUCE HEAVY RAIN. SITUATION WILL HAVE TO
BE CLOSELY MONITORED ONCE WE GET THROUGH THE FLASH FLOODING THREAT
THURSDAY AFTERNOON AND NIGHT. WITH THE UPPER LOW TRYING TO CUT OFF
OVER THE AREA...WE ARE NO LOOKING AT BETTER CHANCES FOR MORE
SHOWERS...ESPECIALLY OVER VERMONT ON FRIDAY AND SATURDAY. EXPECT
PLENTY OF CLOUDS AND WITH THE PRECIPITATION...LOOKING AT BELOW
NORMAL TEMPERATURES AS NORTHERLY LOW LEVEL FLOW DEVELOPS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 415 AM EDT THURSDAY...UPPER LEVEL LOW PRESSURE SYSTEM WILL
REMAIN OVER THE REGION THROUGH SUNDAY NIGHT...THUS LOOKING AT THE
THREAT FOR MORE SHOWERS THROUGH SUNDAY NIGHT...ESPECIALLY FROM THE
CHAMPLAIN VALLEY EASTWARD. THIS UNFORTUNATELY MEANS A COOLER AND WETTER
START TO THE MEMORIAL DAY WEEKEND AND MARATHONERS WILL WANT TO PAY
CLOSE ATTENTION TO THE FORECAST GIVEN THE TREND TOWARD COOLER AND
WETTER WEATHER ON SUNDAY. EVENTUALLY THE UPPER LOW MOVES OUT OF
THE AREA SUNDAY NIGHT INTO MONDAY AND AN UPPER LEVEL RIDGE BUILDS
IN MONDAY THROUGH WEDNESDAY FOR WARMER AND DRIER WEATHER.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
THROUGH 12Z FRIDAY...NUMEROUS SHOWERS AND THUNDERSTORMS WL DEVELOP
ACRS OUR TAF SITES TODAY...WITH MVFR AND PERIODS OF IFR LIKELY IN
THE HEAVIER SHOWERS/STORMS. CRNT RADAR SHOWS LIGHT RAIN SHOWERS
MOVING FROM SW TO NE ACRS WESTERN/NORTHERN NY ATTM...WITH MAINLY
VFR CONDITIONS. OTHERWISE...LOW STRATUS WITH IFR AT MPV WL
DISSIPATE BTWN 12Z-14Z TODAY. CHCS FOR SHOWERS/STORMS WL INCREASE
AFT 15Z...WITH BEST CHC OF IFR CONDITIONS BTWN 17Z-21Z...WHEN
INSTABILITY IS THE GREATEST. OCCASIONAL SHOWERS AND THUNDERSTORMS
WL CONT INTO THE EVENING HOURS...BEFORE SLOWLY WEAKENING WITH
AREAS OF FOG/LOW CLOUDS DEVELOPING. IFR/LIFR CONDITIONS WL BE
LIKELY AT MPV/SLK/PBG WITH MVFR AT MSS/RUT/BTV. ALSO...BREEZY
SOUTHERLY WINDS AT 5 TO 15 KNOTS WITH GUSTS NEAR 20 KNTS
TODAY...WL SHIFT TO THE NORTHWEST TONIGHT.

OUTLOOK 12Z FRIDAY THROUGH MONDAY...THE COMBINATION OF A SFC
BOUNDARY AND ASSOCIATED LOW PRES WL KEEP SHOWERS IN THE TAF SITES
THRU THE WEEKEND. THESE SHOWERS WL PRODUCE PERIODS OF MVFR CIGS
WITH SOME IFR CONDITIONS POSSIBLE...ESPECIALLY AT NIGHT. IN
ADDITION...BREEZY NORTHWEST WINDS WL DEVELOP AS SFC LOW PRES
TRACKS INTO THE GULF OF MAINE ON SUNDAY. A SLOW CLRING TREND IS
ANTICIPATED ON MONDAY.
-- End Changed Discussion --


&&

.HYDROLOGY...
AS OF 415 AM THURSDAY...FLASH FLOOD WATCH EXISTS FROM NOON TODAY
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. THIS SITUATION WILL HAVE TO BE MONITORED.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...FLASH FLOOD WATCH FROM NOON EDT TODAY THROUGH FRIDAY MORNING
     FOR VTZ001>012-016>019.
NY...FLASH FLOOD WATCH FROM NOON EDT TODAY THROUGH FRIDAY MORNING
     FOR NYZ028>031-034-035.

&&

$$
SYNOPSIS...EVENSON
NEAR TERM...EVENSON
SHORT TERM...EVENSON
LONG TERM...EVENSON
AVIATION...TABER
HYDROLOGY...