-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 191142
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
742 AM EDT SUN MAY 19 2013

.SYNOPSIS...
HIGH PRESSURE OFF THE ATLANTIC COAST WILL CONTINUE TO BRING
MAINLY DRY BUT CLOUDY CONDITIONS TO THE NORTH COUNTRY TODAY AND
TONIGHT. A FRONTAL BOUNDARY DROPPING SOUTHWARD FROM CANADA WILL
SERVE AS A FOCUS FOR SHOWERS AND POSSIBLE THUNDERSTORMS ON
MONDAY...WITH DRY CONDITIONS RETURNING FOR MONDAY NIGHT INTO
TUESDAY. THE REMAINDER OF THE WEEK WILL BE UNSETTLED WITH SEVERAL
CHANCES FOR PRECIPITATION.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 704 AM EDT SUNDAY...A MAINLY DRY DAY IS EXPECTED ACROSS THE
NORTH COUNTRY TODAY AS MID/UPPER LEVEL THICKNESS/HEIGHTS CONTINUE
TO RISE AS A WEAK WARM FRONT APPROACHES THE REGION. CURRENT
SATELLITE IMAGERY SHOWS SCT-BKN MID/HIGH CLOUDS STREAMING FROM
NORTHWEST TO SOUTHEAST ACROSS PORTIONS OF THE REGION ASSOCIATED
WITH DECAYED CONVECTIVE ACTIVITY ACROSS THE GREAT LAKES REGION AND
INTO SOUTHERN ONTARIO/QUEBEC RIDING OVER THE CREST OF AN UPPER
RIDGE TO OUR WEST. AS THE RIDGE CONTINUES TO BUILD EASTWARD THIS
ACTIVITY SHOULD REMAIN NORTH OF THE BORDER LEAVING THE NORTH
COUNTRY WITH VARYING AMOUNTS OF MID/HIGH COVER THROUGH THE
DAY. SOME VERY LIGHT SHOWERS NOTED AS WELL ON UPSTREAM CANADIAN
RADAR BUT EXPECT MUCH OF THIS NOT TO REACH THE BTV CWA...BUT SOME
AFTERNOON INSTABILITY SHOWERS REMAIN POSSIBLE. MEAN 925-850MB
TEMPS TODAY ARE SIMILAR TO THOSE OBSERVED YESTERDAY SO HIGHS
SHOULD BE SIMILAR ACCORDINGLY...ALBEIT A COUPLE DEGREES COOLER
GIVEN INCREASED CLOUD COVER. ALSO...EXPECT TO SEE SOME GUSTY WINDS
LOCALLY IN THE CHAMPLAIN VALLEY AS A MODEST SOUTHERLY 925MB JET OF
25-35KTS ASSOCIATED WITH WARM AIR ADVECTION PATTERN MOVES ACROSS
THE REGION. SHOULD SEE SOME GUST UPWARDS OF 25 MPH...LOCALLY
HIGHER AROUND AND ON LAKE CHAMPLAIN.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 439 AM EDT SUNDAY...FOR TONIGHT...AFOREMENTIONED WARM FRONT
AND ASSOCIATED MOISTURE SHIFT NORTHEAST THROUGH THE REGION WITH
CONTINUED CHANCES FOR SOME SHOWERS THOUGH EXPECT OVERALL
CONDITIONS TO BE FAIRLY DRY. THE COMBINATION OF MODEST SOUTHERLY
FLOW AND ABUNDANT CLOUD COVER WILL KEEP TEMPS ON THE MILD SIDE
WITH LOWS HOLDING IN THE 50S FOR MOST AREAS...POSSIBLY IN THE LOW
60S IN THE CHAMPLAIN VALLEY.

FOR THE REMAINDER OF THE SHORT TERM PERIOD THROUGH TUESDAY THE
FORECAST BECOMES MUCH MORE COMPLEX AND CHALLENGING AS THE
AFOREMENTIONED WARM FRONT STALLS ALONG THE INTL BORDER AND
RETREATS SOUTHWARD THROUGH THE REGION AS A QUASI-BACKDOOR COLD
FRONT. GFS AND ECMWF HAVE COME INTO BETTER AGREEMENT IN REGARDS
TO OVERALL SYNOPTIC PATTERN THIS MORNING AND OFFER A DRIER
SCENARIO THAN HAS BEEN ADVERTISED IN THE PREVIOUS DAYS WITH A
MORE AMPLIFIED UPPER RIDGE SHUNTING DEEP LAYER MOISTURE AND LIFT
FARTHER NORTH OF THE CWA. HAVE TRENDED THE FORECAST ACCORDINGLY
LOWERING CHANCES FOR PRECIP TO SLIGHT CHANCE FOR MONDAY AND
MONDAY NIGHT...WITH INCREASING POPS FROM WEST TO EAST TUESDAY AS
THE RIDGE SHIFTS EASTWARD AND UPPER LEVEL LOW ACROSS THE CENTRAL
CONUS APPROACHES. LIKELY THE WARMEST DAY OF THE WEEK WILL BE
MONDAY WITH THE CWA ENTRENCHED IN THE WARM SECTOR WITH HIGHS IN
THE MID 70S TO LOWER 80S EXPECTED. TEMPS FALL BACK INTO THE UPPER
60S NORTH TO LOWER 70S SOUTH FOR TUESDAY AS THE FRONT SAGS
SOUTHWARD.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 407 AM EDT SUNDAY...RATHER UNSETTLED PERIOD ANTICIPATED AS
E-W ORIENTED FRONTAL ZONE WILL BE DRAPED ACROSS/NEAR THE NORTH
COUNTRY. BEGINNING TUESDAY NIGHT...BOTH THE 00Z ECMWF AND 00Z GFS
INDICATE SFC-850MB FRONTAL ZONE WILL BE LIFTING NEWD AS A WARM
FRONT ACROSS OUR REGION. ASSOCIATED ISENTROPIC ASCENT WILL BRING
INCREASING CLOUDS AND A CHANCE FOR RAIN SHOWERS...ESPECIALLY AFTER
MIDNIGHT. ASSOCIATED S-SW WINDS AND CLOUDS WILL ALSO KEEP LOW
TEMPERATURES ON THE MILD SIDE DURING TUESDAY NIGHT...WITH LOWS IN
THE MID 40S TO LOWER 50S (WARMEST CHAMPLAIN VALLEY). ON
WEDNESDAY...IT APPEARS THE NORTH COUNTRY WILL EMERGE INTO THE
CYCLONE WARM SECTOR WITH BROAD/LOW-AMPLITUDE RIDGE IN PLACE ALOFT.
AIR MASS HAS THE POTENTIAL TO BE QUITE MILD; 00Z ECMWF SHOWING
850MB TEMPS OF +14 TO +15C. QUESTION WILL BE AMT OF SUNSHINE IN
WARM SECTOR...WHICH IS A BIT DIFFICULT TO DETERMINE AT THIS POINT.
HAVE ADJUSTED ABOVE MEX-MOS GUIDANCE WITH HIGHS IN THE LOW-MID
70S...BUT THERE IS A CHANCE THAT TEMPS COULD BE CLOSER TO 80F FOR
AFTN HIGHS. AIR MASS MAY ALSO BECOME MARGINAL UNSTABLE...SO
INCLUDED A CHANCE FOR ISOLD/SCT TSTMS DURING THE AFTN/EVENING
HOURS WEDNESDAY. AT THIS POINT...ACTIVITY WILL LIKELY NOT BE WELL-
ORGANIZED...BUT LOCAL OROGRAPHIC EFFECTS AND INSTABILITY MAY BE
SUFFICIENT WITH DAYTIME HEATING TO GENERATE A FEW TSTMS. UPSTREAM
SHORTWAVE TROUGH ACROSS THE GREAT LAKES AMPLIFIES THURSDAY INTO
FRIDAY MORNING AND ASSOCIATED CYCLONIC FLOW AND PASSAGE OF A COLD
FRONT ACROSS THE NORTH COUNTRY WILL BRING ADDITIONAL CHANCES FOR
RAIN SHOWERS THURSDAY INTO FRIDAY (POPS 30-50 PERCENT). TIMING
UNCERTAINTIES REMAIN WITH REGARD TO THIS EVOLUTION...SO MOST
CONCENTRATED TIME FOR ASSOCIATED SHOWERS IS NOT KNOWN. SHOULD
TREND COOLER AND DRIER FOR FRIDAY AND INTO NEXT WEEKEND WITH HIGHS
IN THE MID-UPR 60S. LOWS WILL MAINLY BE IN THE 40S FRIDAY AND
SATURDAY NIGHT.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
THROUGH 12Z MONDAY...MID-UPR CLOUDS WILL INCREASE TODAY WITH
CEILINGS GENERALLY 8-10 KFT. HIGH PRESSURE DRIFTING EWD INTO THE
GULF OF MAINE WILL BRING WINDS AT THE TAF SITES AROUND TO
SOUTH...AND COULD SEE SOME GUSTS 20-24 KTS AT BTV BETWEEN 15-23Z.
BEFORE 14Z...WINDS GENERALLY LIGHT AND VARIABLE. SOUTH TO
SOUTHWEST WINDS AROUND 10 KTS CONTINUE TONIGHT AND PASSAGE OF A
WEAK WARM FRONT MAY BRING SOME MVFR CEILINGS AT KSLK/KMPV DURING
SUNDAY NIGHT. THERE IS A SLIGHT CHANCE OF RAIN SHOWERS THIS
EVENING AND OVERNIGHT...BUT NOT SUFFICIENT TO WARRANT EXPLICIT
INCLUSION IN THE TAF/S ATTM.

OUTLOOK 12Z MONDAY THROUGH THURSDAY... A FRONTAL BOUNDARY SAGGING
SWD FROM ONTARIO/QUEBEC BRINGS THE THREAT FOR SHOWERS AND POSSIBLE
TSTMS FOR MUCH OF NEXT WEEK. THE FRONTAL BNDRY WILL BECOME QUASI-
STATIONARY VCNTY OF NRN NY AND NRN NEW ENGLAND THRU MUCH OF THE
PERIOD. TIMING UNCERTAINTIES CURRENTLY EXIST BUT ANTICIPATE
SEVERAL PERIODS OF MVFR AND PERHAPS BRIEF IFR CONDITIONS DURING
THIS TIME FRAME WITH SHOWERS AND POSSIBLE TSTMS...ESPECIALLY
TUESDAY AND THURSDAY.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...LAHIFF
NEAR TERM...LAHIFF
SHORT TERM...LAHIFF
LONG TERM...BANACOS
AVIATION...BANACOS