Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 210212
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1012 PM EDT WED AUG 20 2014

.SYNOPSIS...
SLOW MOVING LOW PRESSURE WILL BRING UNSETTLED WEATHER TONIGHT AND
THURSDAY FOR MAINLY NORTHERN NEW YORK AND THE WESTERN HALF OF
VERMONT. DRIER WEATHER WILL DEVELOP ON FRIDAY AS HIGH PRESSURE
STARTS TO MOVE INTO THE AREA. THAT HIGH WILL STICK AROUND, GIVING
US A LONG STRING OF DRY AND WARM WEATHER THAT WILL LAST FROM THE
WEEKEND INTO THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 7 AM THURSDAY MORNING/...
AS OF 1012 PM EDT WEDNESDAY...NORTHERN NY CONTINUES TO SEE RAIN
SHOWERS WITH ISOLATED EMBEDDED THUNDERSTORMS MAINLY OVER THE SLV
AND ERN ADKS. THESE SHOWERS ARE SLOW TO PROGRESS EASTWARD WITH
OBSERVATIONS SHOWING RAINFALL AMOUNTS AROUND HALF INCH...AND
ISOLATED HEAVIER AMOUNTS A LITTLE OVER AN INCH...AS INDICATED BY
RADAR. LOCAL MODELS CONTINUE TO HANDLE THE GRADUAL TRACK OF
PRECIP WELL...WITH SOME ISO TO SCT SHOWERS TRYING TO DEVELOP IN
THE UPPER HUDSON/LOWER CHAMPLAIN VALLEY...WHILE MAIN SHIELD OF
PRECIP REMAINS EAST OF THE CPV TIL AFTER 06Z. THIS SLOW
PROGRESSION IS DUE TO THE SOMEWHAT STALLED NATURE/MOVEMENT OF
CLOSED UPPER LOW OVER LAKE HURON.

TEMPS TONIGHT TO RANGE FROM THE MID 50S ACROSS EASTERN VT WHERE
BETTER RADIATIONAL COOLING IS EXPECTED TO THE MID/UPPER 60S IN
NORTHERN NEW YORK UNDER OVERCAST.

&&

.SHORT TERM /7 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 330 PM EDT WEDNESDAY...AFOREMENTIONED UPPER LOW WILL CONTINUE
TO BE THE PRIMARY DRIVER OF NORTH COUNTRY WEATHER THROUGH
THURSDAY NIGHT. NAM/GFS ALL IN GOOD AGREEMENT THAT UPPER LOW OPENS
UP/WEAKENS AS IT PROGRESSES ACROSS THE NORTH COUNTRY THURSDAY INTO
THURSDAY NIGHT. EXPECT SHOWERS TO ONCE AGAIN BE PRIMARILY FOCUSED
ACROSS NORTHERN NY /LIKELY POPS/ ON THURSDAY...THOUGH THE BEST
CHANCE FOR PRECIPITATION ACROSS VT IS ON THURSDAY. AIRMASS STILL
IS FAIRLY MOIST WITH PWS AROUND 1.5" WITH 12Z NAM SHOWING CAPE
VALUES SUPPORTIVE OF THUNDER. THE THUNDER RISK FOR THURSDAY IS
LIMITED GIVEN EXPECTED EXTENSIVE CLOUD COVER AND ALSO LOSING
BETTER DYNAMIC FORCING GIVEN WEAKENING UPPER LOW. THEREFORE I`VE
ONLY GONE WITH SHOWERS THURSDAY. DESPITE 850 TEMPS OF +11 TO
+13C...OVERCAST WILL ONLY KEEP TEMPS IN THE MID 70S. OVERALL
DECREASING TREND IN POPS FOR THURSDAY NIGHT AS UPPER DISTURBANCE
PIVOTS SOUTH OF THE NORTH COUNTRY.

LARGE GRADIENT IN STORM TOTAL QPF /SPANNING WEDNESDAY AFTN THROUGH
12Z FRIDAY/. AMOUNTS RANGE FROM NIL ACROSS THE NORTHEAST
KINGDOM...UNDER 0.5" FOR THE CHAMPLAIN VALLEY...TO UP TO 1.25" FOR
THE ADIRONDACKS AND ST. LAWRENCE VALLEY AREAS.

BY FRIDAY...AN AMPLIFIED UPPER RIDGE WILL BUILD SOUTHWARD TOWARD
QUEBEC AS THE UPPER LOW PASSES INTO THE NORTH ATLANTIC AND WEAKENS
TO AN OPEN WAVE. SOME INSTABILITY SHOWERS STILL POSSIBLE ON FRIDAY
BUT SUBSIDENCE FROM BUILDING UPPER RIDGE WILL WIN OUT BY LATE IN THE
DAY INTO THE EVENING. NOT MUCH CHANGE IN THERMAL PROFILES FOR
FRIDAY...BUT MORE BREAKS IN CLOUDINESS SHOULD ALLOW FOR HIGHS TO
TOP OUT IN THE MID TO UPPER 70S WITH 50S TO AROUND 60 FOR LOWS.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 330 PM EDT WEDNESDAY...12Z GUIDANCE FROM GFS, GFS ENSEMBLES
AND ECMWF ARE ALL IN PRETTY DARN GOOD AGREEMENT WITH EACH OTHER
AND THEIR INDIVIDUAL PREVIOUS RUNS, THUS I WOULD RATE MY
CONFIDENCE IN THE FORECAST AS ABOVE NORMAL. IN SUMMARY, LARGE
SCALE BLOCKING RIDGE DEVELOPS ACROSS THE EASTERN HALF OF THE
COUNTRY, RESULTING IN DRY AND WARMING CONDITIONS INTO THE MIDDLE
PART OF NEXT WEEK (SUMMER WILL HANG ON NEXT WEEK, WHICH MAKES THIS
FORECASTER PERSONALLY HAPPY). WITH THE CLOSENESS AMONG THE MODELS, I
SAW NO REASON TO SIGNIFICANTLY DEVIATE FROM THE PURE BLEND BETWEEN
THEM ALL. HERE ARE THE DAILY SPECIFICS...

SATURDAY...UPPER TROUGH WILL BE PUSHING SOUTH/EAST OF THE AREA.
STILL SOME CYCLONIC FLOW ALOFT SO CAN`T RULE OUT AN ISOLATED LIGHT
SHOWER OR SPRINKLE ACROSS MAINLY THE HIGHER TERRAIN, BUT IN
GENERAL THE FORECAST IS A DRY ONE. CLOSER TO THE SURFACE, HIGH
PRESSURE WILL BE SLOWLY NOSING DOWN FROM THE NORTH. THIS WILL
RESULT IN A LIGHT EASTERLY FLOW. LUCKILY THIS TIME OF THE YEAR THE
ATLANTIC OCEAN WATERS ARE AT THEIR WARMEST SO I DON`T EXPECT ANY
ISSUES WITH WIDESPREAD LOW STRATUS DEVELOPING AS WE WOULD SEE IN
THE SPRING OR EVEN EARLY SUMMER. HOWEVER IT WILL SET UP AN A
TEMPERATURE GRADIENT WHERE IT WILL BE COOLEST EAST OF THE GREEN
MOUNTAINS AND WARMEST IN THE ST LAWRENCE VALLEY. WITH 850MB
TEMPERATURES RUNNING ABOUT 10-12C (EAST TO WEST), HIGHS SHOULD
RANGE FROM THE LOWER 70S IN THE CONNECTICUT VALLEY TO UPPER 70S IN
THE ST LAWRENCE VALLEY. SHOULD BE MOSTLY CLEAR SATURDAY NIGHT.
VALLEY FOG WILL PROBABLY FORM AS TYPICAL THIS TIME OF YEAR. LOWS
GENERALLY IN THE 50S.

SUNDAY...DITTO.

MONDAY...SURFACE HIGH SHOULD BE PRETTY MUCH ON TOP OF THE AREA
ALONG WITH STRONG RIDGING ALOFT. NET RESULT: LOTS OF SUN AND VERY
LIGHT WINDS. 850MB TEMPERATURES RISE TO THE 12-13C RANGE AND WITH
ATMOSPHERIC MIXING, WE SHOULD REALIZE THE FULL POTENTIAL OF WARMTH
WITH HIGHS TOPPING OUT IN THE 70S TO LOWER 80S. MONDAY NIGHT
ANOTHER REPEAT OF CLEAR/CALM/PATCHY FOG.

TUESDAY...ALMOST IDENTICAL TO MONDAY, EXCEPT THE HIGH SINKS JUST A
LITTLE SOUTH OF THE AREA ALLOWING THE FLOW TO TURN MORE
SOUTHWESTERLY. IN RESPONSE, TEMPERATURES WILL RISE A DEGREE OR TWO
FROM MONDAY. 850MB TEMPERATURES WILL BE UP AROUND 12-14C, SO LOOK
FOR LOWER 80S TO BE MORE WIDESPREAD. STILL DEEP LAYER RIDGING AND
A STRONG SUBSIDENCE INVERSION PERHAPS AS LOW AS 7500FT SO ANY
DAYTIME CUMULUS THAT FORMS WILL BE VERY SHALLOW. TUESDAY NIGHT
ANOTHER REPEAT OF MONDAY NIGHT WHICH IS A REPEAT OF SUNDAY NIGHT
WITH IS A REPEAT OF SATURDAY NIGHT.

WEDNESDAY...MODELS BEGIN TO DIVERGE SOME. GFS & IT`S ENSEMBLE MEAN
KEEP THE UPPER RIDGE STRONG, MEANING LOTS O` SUN. ECMWF FLATTENS
THE RIDGE IN RESPONSE TO A STRONG SHORTWAVE PASSING BY TO THE
NORTH AND BRINGS IN SOME MOISTURE TO NORTHERN NY LATE IN THE DAY
SUGGESTING A FEW SHOWERS/T-STORMS ABOUT. WITH THE BLEND I USED, I
LEANED MORE TOWARD THE GFS SOLUTION, BUT PAINTED IN SOME 10-20%
POPS IN NORTHERN NY. THE BASIC WORDED FORECAST WILL INDICATE A DRY
DAY. 850MB TEMPERATURES RISE TO 14-16C OR SO, THUS EVEN MORE OF
THE AREA WILL BE POKING ABOVE THE 80F MARK -- WITH EVEN A FEW
LOCATIONS IN THE CHAMPLAIN/ST LAWRENCE VALLEY PUSHING INTO THE MID 80S.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY....OVERALL LOOKING AT VFR CONDITIONS BUT AREA
OF SHOWERS WILL BE MOVING ACROSS THE AREA THROUGH ABOUT 12Z AND
THUS EXPECTING PERIODS OF MVFR CONDITIONS WITH RESPECT TO CEILINGS
AND VISIBILITIES WITH THE SHOWERS. THIS BAND OF SHOWERS WILL MOVE
OUT OF THE AREA BETWEEN 12Z AND 18Z AND CONDITIONS WILL RETURN TO
VFR. WINDS WILL GENERALLY BE UNDER 10 KNOTS THROUGH THE PERIOD AND
FROM THE SOUTHEAST...ESPECIALLY AFTER 12Z.

OUTLOOK 00Z FRIDAY THROUGH MONDAY...00Z FRI TO 00Z SAT...AREAS
OF MVFR WITH ANY SHOWERS.

00Z SAT ONWARD...VFR, EXCEPT IFR IN LATE NIGHT VALLEY FOG
(PRIMARILY MPV AND SLK).

&&

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

&&

$$
SYNOPSIS...LOCONTO
NEAR TERM...KGM/LOCONTO
SHORT TERM...LOCONTO
LONG TERM...NASH
AVIATION...EVENSON/NASH






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