Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 301444
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1044 AM EDT TUE SEP 30 2014

.SYNOPSIS...
VARIABLE CLOUDS WITH MAINLY DRY AND SEASONABLY MILD EARLY FALL
WEATHER WILL PERSIST ACROSS THE REGION THROUGH FRIDAY AFTERNOON AS
HIGH PRESSURE REMAINS ACROSS THE AREA. THE NEXT CHANCE FOR
WIDESPREAD SHOWERS WILL OCCUR BY FRIDAY NIGHT INTO SATURDAY AS A
COLD FRONT PUSHES ACROSS THE REGION. BEHIND THIS
SYSTEM...COOLER...CLOUDIER WEATHER IS EXPECTED FOR THE EARLY
PORTIONS OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1043 AM EDT TUESDAY...DIFFICULT SKY FORECAST FOR
TODAY...WITH LOW CLOUDS ASSOCIATED WITH MARINE LAYER MOISTURE FROM
THE ATLANTIC ACROSS EASTERN AND SOUTHERN VERMONT PER LATEST
VISIBLE SATELLITE LOOP. PARTLY SUNNY SKIES ACROSS MOST OF THE
CHAMPLAIN VALLEY AND THE ADIRONDACKS...WITH MOST CLOUDY SKIES IN
THE VICINITY OF THE SAINT LAWRENCE RIVER IN NORTHERN NEW YORK.
EXPECTING CLOUD COVER TO LINGER MOST OF TODAY ACROSS EASTERN AND
SOUTHERN VERMONT...AS KCXX 88D VAD WIND PROFILE SHOWING VERY LIGHT
WINDS IN THE LOW LEVELS OF THE ATMOSPHERE. HAVE LOWERED MAX
TEMPERATURES FOR TODAY WHERE CLOUD COVER STILL PERSISTS.

PREVIOUS DISCUSSION FROM 721 AM EDT TUESDAY...MINOR ADJUSTMENTS
TO SKY/T/TD DATA TO MATCH CURRENT OBSERVATIONAL TRENDS...OTW
FORECAST REMAINS IN GOOD SHAPE DESPITE THE SOMEWHAT CHALLENGING
CLOUD FORECAST TODAY. PRIOR DISCUSSION FOLLOWS...

PRIOR DISCUSSION...
MAINLY A WIND DIRECTION/CLOUD FORECAST CHALLENGE FOR TODAY AS
BACKDOOR SFC FRONT HAS SNAKED ITS WAY SOUTH/SOUTHWEST INTO THE ST
LAWRENCE AND CHAMPLAIN VALLEYS WHILE FURTHER EAST HAS PUSHED WEST
FROM THE NEW ENGLAND COASTAL PLAIN INTO ERN PORTIONS OF VT.
FRONTAL ZONE IS SHALLOW (UP TO ABOUT 2 KFT) AND TAKING ON CLASSIC
DENSITY CURRENT FLOW BEHAVIOR...SO ADIRONDACKS AND HIGHER TERRAIN
OF GREENS LARGELY UNAFFECTED BY THIS MODEST AIRMASS CHANGE. FOR
TODAY WILL MAINTAIN PRIOR IDEA OF VARIABLE CLOUD COVER ACROSS THE
AREA...WITH PARTIAL SUN MOST PREVALENT IN THE CHAMPLAIN VALLEY AND
ADIRONDACKS AND HIGHEST CLOUD COVER IN VALLEYS OF ERN VT WHERE
LIGHT EASTERLY MARITIME FLOW WILL CONTINUE. ANY PATCHY -DZ IN ERN
VT THIS MORNING SHOULD END BY AFTERNOON HOWEVER AS PBL WARMS/DRIES
SLIGHTLY. WINDS LIGHT AND LESS THAN 10 KTS TODAY...BUT QUITE
VARIABLE AS EVIDENT FROM CURRENT (07Z) SFC OBSERVATIONS SHOWING
WINDS NORTHEASTERLY AT KMSS...NORTHERLY AT KPBG/KBTV...SOUTH AT
KMPV...SOUTHEAST AT KRUT AND CALM AT KSLK...YOU GET THE PICTURE.
ONLY OTHER SLIGHT ADJUSTMENT WAS TO ADD AN OUTSIDE SHOT OF A
SHOWER ACROSS THE SWRN PORTIONS OF THE ADIRONDACKS AS CLOSED H5
LOW DROPS ESE FROM THE LOWER LAKES INTO THE NRN MID ATLANTIC
REGION BY EVENING. MODELS REMAIN CONSISTENT IN SHOWING THIS SMALL
AREA WILL LIE IN A NARROW INSTABILITY AXIS (200-400 J/KG)
COINCIDENT WITH A WEAK MID LEVEL DEFORMATION ARM EXTENDING
NORTHEAST FROM THE LOW CENTER. QPF WILL BE SCT AND LIGHT AT BEST
HOWEVER. STAYED AWAY FROM BIAS-CORRECTED TEMPERATURE DATA GIVEN
OUR SLIGHT REGIME CHANGE OFFERING VALUES RANGING THROUGH THE 60S
TO LOCALLY AROUND 70 IN THE CHAMPLAIN AND SWRN ST LAWRENCE
VALLEYS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
AS OF 355 AM EDT TUESDAY...FROM TONIGHT ONWARD INTO THURSDAY
PRETTY MUCH A PERSISTENCE/DRY FORECAST WILL BE OFFERED AS WEAK
HIGH PRESSURE REMAINS IN CONTROL OF NRN NY/VT WEATHER AS
AFOREMENTIONED CLOSED H5 LOW SLIDES TO OUR SOUTH AND OFF THE
SOUTHERN NY/NEW ENGLAND COAST. CLOUDS AGAIN QUITE VARIABLE WITH
PARTIAL SUN EXPECTED HERE AND THERE...MOST PREVALENT CHAMPLAIN
VALLEY WEST AND LESS SO EASTERN COUNTIES WITH EVIDENCE OF ANOTHER
EASTERLY MARITIME PUSH WEDNESDAY NIGHT/THURSDAY MORNING.
TEMPERATURES FAIRLY CONSISTENT AS WELL WITH DAILY HIGHS WED/THU
FROM THE MID 60S TO LOWER 70S (COOLEST ERN VT) AND OVERNIGHT LOWS
IN THE UPPER 40S TO LOWER 50S.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 434 AM EDT TUESDAY...THE LARGE WESTERN CONUS MID-LEVEL
TROUGH FINALLY SHIFTS INTO THE CENTRAL/NORTHERN PART OF THE CONUS
LATE IN THE WEEK INTO THE WEEKEND WITH AN ACCOMPANYING SURGE OF
CONTINENTAL POLAR AIR AWAITING BEHIND THE COLD FRONT. THIS IS
FAIRLY WELL AGREED UPON BY THE GFS AND THE INTERNATIONAL MODELING
SUITE...THOUGH DIFFERENCES IN FRONTAL TIMING REMAIN APPARENT. THAT
BEING SAID...IT`S PRETTY CLEAR THAT A CHANGE FROM THE RECENT WARM
DRY WEATHER/AMPLIFIED RIDGE PATTERN IS IN THE OFFING BASED ON
ABOVE GUIDANCE AND GFS ENSEMBLE DEPICTION OF SHARPLY NEGATIVE
ARCTIC OSCILLATION (AO) TELECONNECTION INTO EARLY OCTOBER.

COLD FRONT LOOKS TO APPROACH THE NORTH COUNTRY FRIDAY OR SATURDAY.
THE GFS IS ABOUT 6-12 HOURS QUICKER THAN THE ECMWF IN PUSHING THE
FRONT ACROSS THE NORTH COUNTRY. GIVEN HOW AMPLIFIED THE MID-LEVEL
PATTERN IS...I`M MORE APT TO BELIEVE THE SLOWER ECMWF TIMING
THOUGH. THEREFORE...WHILE I STILL THINK LIKELY POPS ARE WARRANTED
I`VE SLOWED THE TIMING BACK UNTIL SATURDAY AFTN FOR NORTHERN NY
AND SATURDAY NIGHT FOR VT. GIVEN PROGGED SHARP 500-MB HEIGHT FALLS
AND SYNOPTIC/FRONTAL FORCING...A FINE LINE MORE CLOSELY TIED TO
THE FRONT WOULD BE A PLAUSIBLE SCENARIO. I`VE ACTUALLY SHOWN RAIN
AS OPPOSED TO RAIN SHOWERS AS POPS TREND TO LIKELY TO BETTER SHOW
THAT SCENARIO. COLD ADVECTION BEHIND THE FRONT SENDS 925 MB TEMPS
TO AROUND +3 TO +5C BY SUNDAY AND MOSTLY STAY AROUND THAT RANGE
INTO MONDAY. ONLY LOOKING AT HIGHS IN THE UPPER 50S/LOW 60S SUNDAY
UNDER MOSTLY CLOUDY SKIES AND LINGERING CHANCE POPS FOR LAKE-
EFFECT RAIN SHOWERS. MEAN CYCLONIC FLOW CONTINUES MONDAY INTO
TUESDAY BUT WITH SLIGHT MODERATION TO TEMPS LATER MONDAY INTO
TUESDAY AS MID-LEVEL FLOW BECOMES SOUTHWESTERLY. ANOTHER SHORTWAVE
TROUGH BRINGS ABOUT INCREASING POPS AREAWIDE FOR MONDAY NIGHT INTO
TUESDAY.

TEMPERATURES INITIALLY BEGIN ABOUT 5-10 DEGREES ABOVE NORMAL BEFORE
TRENDING A COUPLE DEGREES BELOW NORMAL FOR LATER IN THE WEEKEND. A
RETURN TO MORE SEASONAL TEMPS IS THEN ANTICIPATED FOR NEXT WEEK.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
THROUGH 12Z WEDNESDAY...HODGEPODGE OF FLIGHT CATEGORIES CONTINUES
EARLY THIS MORNING PRIMARILY FROM CEILINGS. SOUTHEAST STRATUS DECK
FROM BACKDOOR FRONT STILL CONTINUES AT MPV AND TO SOME DEGREE AT
RUT AS WELL...MEANWHILE STRATUS LAYER AT MSS FROM FRONT/INVERTED
TROUGH WITH NORTHEAST FLOW. TAF FORECAST IS LARGELY BASED ON
EXTRAPOLATION OF CURRENT OBS WITH GUIDANCE POORLY DEPICTING
CURRENT CONDITIONS. EXPECT LONGEST DURATION OF IFR CEILINGS AT
MSS. AS SFC LOW NEAR EASTERN GREAT LAKES SHIFTS SOUTH EXPECT
LOWERING CEILINGS TO SLK...PBG AND BTV LATER IN THE DAY AND
CONTINUING INTO THE EVENING. CEILINGS LIKELY MVFR TO IFR AT ANY OF
THESE SITES. SOUTHEAST FLOW LOOKS TO PERSIST AT MPV BUT LIKELY
MORE IN THE MVFR RANGE. WINDS HIGHLY VARIABLE AT EACH TAF SITE.

OUTLOOK 12Z WEDNESDAY THROUGH SATURDAY...

12Z WED - 00Z THU...CEILINGS TO IMPROVE FROM NORTH TO SOUTH.
LINGERING MVFR CEILINGS STILL POSSIBLE AT MPV WITH EAST FLOW.

00Z THU - 00Z SAT...GENERALLY VFR CONDITIONS UNDER HIGH PRESSURE.
LATE NIGHT AND EARLY MORNING LIFR/FOG AT KMPV/KSLK LIKELY FROM
06-13Z EACH DAY.

00Z SATURDAY THROUGH 00Z SUNDAY...VFR TRENDING TO MVFR IN SHOWERS
AS A COLD FRONT TRACKS INTO THE REGION. GUSTY SOUTHERLY WINDS AND
LLWS POSSIBLE...ESPECIALLY IN THE CHAMPLAIN AND ST. LAWRENCE
VALLEYS.

&&

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

&&

$$
SYNOPSIS...JMG
NEAR TERM...JMG/WGH
SHORT TERM...JMG
LONG TERM...LOCONTO
AVIATION...LOCONTO






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