Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 200545
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
145 AM EDT WED AUG 20 2014

.SYNOPSIS...
HIGH PRESSURE TO REMAIN IN CONTROL ACROSS THE NORTH COUNTRY
WITH DRY WEATHER OVERNIGHT. A SLOW-MOVING LOW PRESSURE AREA WILL
MOVE ACROSS THE NORTH COUNTRY WEDNESDAY INTO THE FRIDAY. SHOWERS
AND THUNDERSTORMS FROM THIS SYSTEM WILL BE PRIMARILY FOCUSED
ACROSS NORTHERN NEW YORK WITH LESS AREAL COVERAGE ACROSS VERMONT.
DRY WEATHER THEN RETURNS WITH GENERALLY SEASONABLE TEMPERATURES
FOR THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 116 AM EDT WEDNESDAY...MAINLY CLEAR SKIES ACROSS THE REGION
AT THIS TIME. PREVIOUS FORECAST OF CLEAR SKIES FOR THE OVERNIGHT
PERIOD STILL LOOKS GOOD...SO NO CHANGES MADE.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 415 PM EDT TUESDAY...THE MAIN FEATURES IN THE SHORT-TERM
PERIOD IS THE CLOSED UPPER LOW AND ITS ASSOCIATED SURFACE LOW NOW OVER
THE GREAT LAKES REGION. THOSE TWO FEATURES WILL SLOWLY MAKE THEIR
WAY TOWARD THE NORTH COUNTRY WEDNESDAY INTO WEDNESDAY NIGHT. A
GENERAL WEAKENING TREND IS OFFERED BY MAJORITY OF THE MODEL
GUIDANCE WITH THESE FEATURES ON THURSDAY AS THE UPPER DISTURBANCE
PASSES SOUTH OF SOUTHERN NEW ENGLAND.

SURFACE WARM FRONT TIED TO THE SURFACE LOW WILL SPREAD NORTHEASTWARD
DURING THE MORNING/AFTERNOON HRS WEDNESDAY. MOST OF THE RAIN WILL BE IN
A WARM SECTOR WITH DEW POINTS IN THE 60S AND PWS OF 1-1.5"...BUT
THAT AIR MASS WILL PRIMARILY ESTABLISH ITSELF ACROSS NORTHERN NY TAKE
ITS TIME TO MAKE ITS WAY INTO VT. SOURCES OF SYNOPTIC-SCALE LIFT
ARE MODEST /PRIMARILY FROM DIFFLUENCE ALOFT AND WEAK CYCLONIC
VORTICITY ADVECTION/...BUT SURFACE-BASED CAPES OF 1000 J/KG OR LESS WILL
SUPPORT A SLIGHT CHANCE FOR AFTERNOON THUNDERSTORMS ACROSS NORTHERN NY.
I`VE CONTINUED TO SHOW A SLOW INCREASE IN POPS FROM SLIGHT CHANCE
FOR THE NY SIDE OF THE CHAMPLAIN VALLEY TO HIGH CHANCE/LIKELY BY
WEDNESDAY EVENING FURTHER INCREASING TO LIKELY/CATEGORICAL THROUGH
WEDNESDAY NIGHT...WITH SLIGHT CHANCE/CHANCE POPS ENTERING INTO
THE CHAMPLAIN VALLEY OF VT. SIMILAR AREAL COVERAGE TO POPS FOR
THURSDAY WITH GENERAL DECREASING TREND INTO THE EVENING. MAJORITY
OF THE QPF THROUGH THURSDAY NIGHT WILL BE ACROSS NORTHERN NEW
YORK WITH AMOUNTS .5"-.75" WITH AMOUNTS IN VT A QUARTER-INCH OR
LESS.

HIGHS WEDNESDAY RANGE FROM THE MID/UPPER 70S ACROSS NORTHERN NY
/DUE TO MORE CLOUD COVER/ TO THE LOWER/MID 80S...WITH LOWS IN THE
50S TO THE LOWER-MID 60S. FOR THURSDAY EXPECTING HIGHS TO RUN IN
THE 70S AND LOWS IN THE 50S.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 416 PM EDT TUESDAY...AN AMPLIFIED PATTERN CONTINUES TO BE
OFFERED BY TODAY`S 12Z GFS AND ECMWF...FEATURING A REX BLOCK AND A
BUILDING MID-LEVEL RIDGE AXIS JUST WEST OF THE ST. LAWRENCE
VALLEY. THE UPPER LOW FROM THE PREVIOUS PERIOD ESSENTIALLY STALLS
NEAR OR JUST EAST OF THE 40N/70W BENCHMARK. THERE STILL IS A BIT
OF DISAGREEMENT INTO EARLY NEXT WEEK FROM THE GLOBAL MODELS ON HOW
THIS PATTERN BREAKS DOWN. THE GFS TAKES THE CLOSED LOW
NORTHEASTWARD MONDAY NIGHT/TUESDAY...WHILE THE ECMWF KEEPS IT
AROUND A LITTLE LONGER /ACTUALLY RETROGRADING SOUTHWESTWARD
TOWARDS THE CAROLINA COAST ON TUESDAY/.

LINGERING SLIGHT CHANCES FOR SHOWERS FOR FRIDAY. OTHERWISE...A
LARGELY DRY PERIOD FOR THE WEEKEND INTO EARLY NEXT WEEK WITH A
RIDGE OF HIGH PRESSURE EXTENDS ACROSS THE NORTH COUNTRY FROM A
BROAD HIGH OVER THE CANADIAN MARITIMES. THERE IS SOME EVIDENCE IN
1000-500MB THICKNESS FIELDS AND 850/925MB THERMAL PROGS OF
MARITIME AIR MASS/BACKDOOR COLD FRONTAL FEATURE KEEPING EASTERN VT
COOLER AND CLOUDIER THAN THE REST OF THE CWA. HIGHS GENERALLY IN
THE 70S /LOWER 70S EASTERN VT/ WITH LOWS IN THE 50S.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...AVIATION CHALLENGE WL BE AREAL COVERAGE OF
FOG THIS MORNING...FOLLOWED BY CHCS FOR SHOWERS THIS AFTN/EVENING
ACRS NORTHERN NY. CRNT SFC ANALYSIS SHOWS HIGH PRES ACRS THE CT
RIVER VALLEY WITH A SFC WARM FRNT LIFTING ACRS WESTERN/CENTRAL NY
ATTM. THIS FEATURE HAS PRODUCE SOME MID LVL CLOUDS...ALONG WITH
TIGHTEN THE GRADIENT ACRS NNY. THIS FACTORS WL LIMIT FOG/BR
POTENTIAL AT MSS/SLK...WL USE A TEMPO FOR IFR AT SLK BTWN 07-10Z.
OTHERWISE...STILL THINKING IFR/LIFR CONDITIONS ARE LIKELY AT MPV
BY 07Z THRU 12Z THIS MORNING IN FOG. FOG WL LIFT BY 13Z WITH VFR
CONDITIONS PREVAILING AT ALL SITES TODAY. CLOUDS WL CONT TO
INCREASE AND THICKEN FROM SW TO NE TODAY ACRS OUR TAF SITES WITH
SOME LIGHT RAIN SHOWER ACTIVITY LIKELY ACRS THE DACKS BY 21Z
TODAY. A BRIEF PERIOD OF MVFR CIGS/VIS WL BE POSSIBLE IN THE
HEAVIER SHOWERS TWD 00Z THIS EVENING. LIGHT TRRN DRIVEN WINDS THIS
MORNING WL BECOME SOUTH/SOUTHEAST AT 4 TO 8 KNOTS...EXCEPT EAST AT
MSS.

OUTLOOK 06Z THURSDAY THROUGH SUNDAY...
ADDITIONAL SHOWERS ARE LIKELY OVERNIGHT INTO THURSDAY WITH PERIODS
OF MVFR CIGS/VIS...ESPECIALLY AT SLK/MPV. FOG/BR WL BE LIMITED BY
THE INCREASING CLOUDS AND THREAT FOR SHOWERS. SFC HIGH PRES ACRS
NORTHERN MAINE WL BUILD INTO OUR TAF SITES ON SATURDAY INTO SUNDAY
WITH VFR CONDITIONS LIKELY. THE COMBINATION OF CLR SKIES AND LIGHT
WINDS WL RESULT IN FOG/BR AT SLK/MPV BOTH SAT AND SUN MORNINGS
WITH IFR CONDITIONS LIKELY.

&&

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

&&

$$
SYNOPSIS...LOCONTO
NEAR TERM...WGH
SHORT TERM...LOCONTO
LONG TERM...LOCONTO
AVIATION...TABER







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