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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 180433
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1233 AM EDT SAT MAY 18 2013

.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL CONTINUE TO BUILD DOWN FROM
EASTERN CANADA AND PERSIST OVER NORTHERN NEW ENGLAND THROUGH MUCH OF
THE WEEKEND. LOOK FOR MORE DRY WEATHER WITH JUST A SLIGHT CHANCE OF
SHOWERS SUNDAY AFTERNOON AND NIGHT. A GRADUAL WARMING TREND IS ALSO
EXPECTED FOR THE WEEKEND.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
-- Changed Discussion --
AS OF 1232 AM EDT SATURDAY...INHERITED FORECAST IN GOOD SHAPE FOR
THE REMAINDER OF THE NIGHT WITH ONLY A FEW TWEAKS NEEDED TO
TEMPS/DEWPOINTS TO MATCH OBSERVATIONAL TRENDS. STILL DEALING WITH
SOME PESKY CLOUDS ACROSS NORTH-CENTRAL/NORTHEAST VERMONT...WHICH
WILL LIKELY STICK AROUND THROUGH MUCH OF THE NIGHT...LIMITING
TEMPS FROM DROPPING TOO FAR BELOW 40. OTHERWISE...LOW TEMPS STILL
EXPECTED TO FALL INTO THE 30S TO LOW 40S FOR THE REST OF THE
AREA...WITH A FEW UPPER 20S IN THE COLDEST AREAS OF THE
ADIRONDACKS WHERE AREAS OF FROST ARE POSSIBLE.
-- End Changed Discussion --

&&

.SHORT TERM /8 AM THIS MORNING THROUGH SUNDAY NIGHT/...
AS OF 317 PM EDT FRIDAY...LOW LEVEL FLOW BEGINS TO GRADUALLY BACK TO
THE WEST ON SATURDAY AND EVENTUALLY THE SOUTHWEST ON SUNDAY. THIS
WILL ALLOW A WARMING TREND TO BEGIN WITH HIGH TEMPERATURES ABOUT 5
TO 10 DEGREES WARMER THAN TODAY. DRY AIR MASS IN PLACE WILL RESULT
IN NO PRECIPITATION ON SATURDAY AND MOST OF SUNDAY. THERE IS A
LITTLE RETURN FLOW ON SUNDAY...BUT NO FORCING AND INSTABILITY IS A
BIT WEAK. HAVE KEPT A SLIGHT CHANCE GOING OVER PARTS OF OUR
SOUTHERN AND WESTERN AREAS CLOSER TO ANY SORT OF INSTABILITY
SUNDAY AFTERNOON AND EVENING.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 345 PM EDT FRIDAY...OVERALL A MORE ACTIVE PATTERN
ANTICIPATED FOR DAYS 4 THRU 7 WITH SEVERAL CHANCES FOR SHOWERS AND
MAYBE SOME THUNDERSTORMS. STILL ANTICIPATING A COMPLEX MID/UPPER
LVL PATTERN ACRS THE NE/EASTERN CONUS WITH TROF ACRS EASTERN
CANADA...DEVELOPING RIDGE OVER THE SE...AND CLOSED 5H/7H
CIRCULATION ACRS THE PLAINS. THIS WL CREATE A FAST WESTERLY FLW
ACRS OUR CWA...WITH EMBEDDED VORTS EJECTING FROM CENTRAL PLAINS
SYSTEM EVERY COUPLE OF DAYS. THIS VORTS WL RIDE ALONG A SFC
BOUNDARY PROGGED TO BE FROM THE GREAT LAKES/OHIO VALLEY INTO
SNE/NE CONUS THRU THE PERIOD. THE EXACT POSITION OF THIS BOUNDARY
WL PLAY A MAJOR ROLE IN TEMPS/INSTABILITY/POPS AND PLACEMENT OF
HEAVIEST QPF. GFS/ECMWF CONT TO SHOW DIFFERENT SOLUTIONS WITH
REGARDS TO BOUNDARY AND ASSOCIATED SHARP THERMAL GRADIENT. GIVEN
THE UNCERTAINTY AND POTENTIAL FOR SEVERAL WEAK AREAS OF LOW PRES
TO DEVELOP ALONG THE FRONT...WL CONT TO MENTION CHC POPS FOR TUES
THRU THURS. THE HIGHEST CHC POPS WOULD BE TUES...AS COLD FRNT
DROPS SOUTH...THEN AGAIN ON THURS. STILL SOME QUESTION WITH
REGARDS TO AMOUNT OF SFC HEATING...ESPECIALLY WITH EXPECTED CLOUD
COVER...BUT SOME INSTABILITY WL BE PRESENT ALONG AND SOUTH OF THE
BOUNDARY ON TUES...WITH CAPE VALUES APPROACHING 1000 J/KG. HAVE
MENTION SCHC FOR THUNDER. OTHERWISE...TIGHT THERMAL GRADIENT FROM
MONDAY THRU THURS ACRS OUR CWA...WL MAKE TEMP FCST TRICKY. IF WE
PUSH WELL INTO THE WARM SECTOR...WHICH IS POSSIBLE ON
MONDAY/TUES...TEMPS AHEAD OF SFC COLD FRNT COULD BE WELL INTO THE
80S...GIVEN PROGGED 85H TEMPS NEAR 14C. BUT IF BOUNDARY GETS HUNG
UP...AND MORE CLOUDS/PRECIP LINGER...THAN HIGHS WOULD ONLY BE IN
THE 60S. HAVE TRENDED SLIGHTLY ABOVE NORMAL WITH HIGHS MAINLY IN THE
70S AND LOWS IN THE U40S TO NEAR 60F THRU THE PERIOD.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 18Z SATURDAY...VFR THROUGH THE PERIOD AS HIGH PRESSURE
CRESTS ATOP THE REGION. LIGHT AND VRB FLOW GENERALLY 5 KTS OR LESS
     DOMINATED BY SLOPE/VALLEY FLOW TONIGHT AND LAKE BREEZES AND/OR
TERRAIN-INFLUENCED FLOW TOMORROW AFTERNOON AS P-GRADIENT REMAINS
VERY LIGHT. ANY SCT/BKN CIGS FROM 070-090 KFT EARLY THIS EVENING
TO TREND SKC OVERNIGHT...THEN SKC TOMORROW WITH PERHAPS SOME
AFTERNOON SHALLOW CUMULUS AT VT TERMINALS AFTER 15Z.

OUTLOOK 18Z SATURDAY THROUGH WEDNESDAY...
VFR FROM 18Z THRU TUESDAY...WITH CHCS INCREASING FOR SHOWERS BY
EARLY NEXT WEEK. THIS COULD RESULT IN A PERIOD OF MVFR
CIGS/VIS...ESPECIALLY ON TUES IN THE HEAVIER SHOWERS. IN
ADDITION...A SPRINKLE ASSOCIATED WITH A WARM FRNT WL BE POSSIBLE
LATE SUNDAY INTO EARLY MONDAY.

&&

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

&&

$$
SYNOPSIS...EVENSON
NEAR TERM...LAHIFF
SHORT TERM...EVENSON
LONG TERM...TABER
AVIATION...JMG/TABER