-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 231942
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
342 PM EDT THU MAY 23 2013

.SYNOPSIS...
SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS AFTERNOON. 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 RECEIVE 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 8 PM THIS EVENING/...
AS OF 147 PM EDT THURSDAY...SLIGHT TWEAKS TO TEMPS THIS
AFTERNOON. SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE
REGION AND LINING UP WITH POTENTIAL FOR TRAINING AND VERY HEAVY
RAIN.

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 FOR MOST OF THE NORTH COUNTRY.

&&

.SHORT TERM /8 PM THIS EVENING 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 THURSDAY/...
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 /20Z THURSDAY THROUGH TUESDAY/...
THROUGH 18Z FRIDAY...VFR/MVFR COND THIS AFTNOON AS RW/TRW DEVELOP
OVER AREA. THRU 00Z FRI...VSBY 2-5SM IN -RW/FG W/ LOWEST VSBY IN
TRW. CEILINGS RANGING FROM BKN015-035 W/ LWR CEILINGS FOR CB/TRW
DEVELOPMENT. AFT 00Z FRI...-RW/FG WILL PERSIST WITH VSBY DOWN TO
3-6SM. CEILINGS WILL DROP TO MAINLY OVC010-015 W/ SCT CLDS BLW
OVC010. WINDS SSW 10-20KTS THRU 00Z-02Z FRI THEN SHIFTING TO NW-
NE 5-15KTS.

OUTLOOK 18Z FRIDAY THROUGH TUESDAY...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...W/ VFR CONDITIONS TUESDAY.

&&

.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.

&&

.MARINE...
-- Changed Discussion --
A LAKE THUNDERSTORM ADVISORY IS IN EFFECT FOR TONIGHT FOR THE
ENTIRE LAKE AREA. THUNDERSTORMS WILL DEVELOP AND MOVE ACROSS THE
LAKE TONIGHT AS A FRONTAL BOUNDARY MOVES IN FROM THE WEST.
EXPECTING HEAVY RAINFALL TO OCCUR WITH ANY POTENTIAL
STORMS...ALONG WITH STRONG WIND/WAVE OCCURRENCE IN VICINITY OF ANY
THUNDER.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...SISSON
NEAR TERM...SISSON
SHORT TERM...EVENSON
LONG TERM...EVENSON
AVIATION...JN/TABER
HYDROLOGY...EVENSON
MARINE...JN