Area Forecast Discussion
Issued by NWS Burlington, VT

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000
FXUS61 KBTV 201943
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
343 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 330 PM EDT WEDNESDAY...UPPER LOW CONTINUES TO MEANDER ACROSS THE
NORTHERN GREAT LAKES REGION...WITH WEAK MID-LEVEL RIDGING IN
PLACE ACROSS VT. ONGOING LINE OF SHOWERS AND EMBEDDED
THUNDERSTORMS CONTINUES ACROSS CENTRAL NY STATE. IT HAS BEEN VERY
SLOW TO MOVE NORTHWARD TODAY WITH LIGHT DEEP-LAYER WINDS PRODUCING
SLOW STORM MOTIONS /LESS THAN 20 KTS/. AIRMASS IS SLIGHTLY MORE
UNSTABLE FURTHER SOUTH...BUT LAPS CAPE VALUES RANGE FROM NIL
ACROSS VT TO AROUND 1500 J/KG IN THE LOWER ST. LAWRENCE VALLEY AND
ADIRONDACKS. HI-RES GUIDANCE CONSENSUS /HRRR...BTV-4 AND NMM-ARW/
LIFTS THIS AREA OF SHOWERS AND STORMS INTO NORTHERN NY LATER THIS
AFTERNOON...WITH SHOWERS CONTINUING THROUGH THE OVERNIGHT. LOCALLY
HEAVY DOWNPOURS ARE POSSIBLE AND WILL MENTION THIS IN HWO. 1-/3-HR
FFG IS RELATIVELY HIGH (ABOUT 2.5" NEEDED IN 3 HR PERIOD) SO NOT
THINKING ANY FLASH FLOODING. PRETTY GOOD AGREEMENT THAT THE RAIN
SHIELD NEVER MAKES IT INTO THE CHAMPLAIN VALLEY UNTIL LATER THIS
EVENING...AND AFTER MIDNIGHT INTO CENTRAL VERMONT. POPS RANGE FROM
SLIGHT CHANCE/CHANCE ACROSS VERMONT TO LIKELY/LOW CATEGORICAL
ACROSS THE ADIRONDACKS AND ST. LAWRENCE VALLEY.

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 PROGESSES 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
GENERALL 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 /19Z WEDNESDAY THROUGH MONDAY/...
THROUGH 18Z THURSDAY....CURRENTLY VFR ACROSS THE REGION. DAYTIME
HEATING CUMULUS CLOUDS ARE DEVELOPING ACROSS THE HIGHER TERRAIN OF
THE ADIRONDACKS AND ANTICIPATE ISOLATED SHOWERS SHOULD BE FORMING
SOON (SO HAVE COVERED SLK WITH VCSH THE NEXT FEW HOURS). WATCHING
SLOW MOVING AREA OF SHOWERS AND ISOLATED THUNDERSTORMS OFF TO THE
WEST AND SOUTHWEST. ULTIMATELY THIS WILL MOVE INTO NORTHERN NEW
YORK AND AFFECT TAF LOCATIONS SUCH AS KMSS & KSLK. HARD TO
SPECIFICALLY PINPOINT EXACTLY WHERE CONVECTION WILL BE AT EXACT
TIMES, SO IN GENERAL THE CONFIDENCE IN THE OVERALL SPECIFICS IN
THE FORECAST IS NOT ALL THAT GREAT. HAVE INCLUDED THE VCSH/VCTS.
TOOK A STAB AT A LITTLE MORE WIDESPREAD LIGHT SHOWER ACTIVITY
OCCURRING AFTER 00Z FOR THE NORTHERN NEW YORK LOCATIONS WITH
PREDOMINANTE -SHRA IN THE TAFS. FOR THE CHAMPLAIN VALLEY AND
POINTS EAST, THE SHOWERS WON`T BE GETTING EVEN CLOSE ENOUGH UNTIL
WELL AFTER 00Z AND PROBABLY WON`T BE AS CONCENTRATED. THUS VCSH
FOR A GOOD CHUNK OF THE NIGHT. GUIDANCE AGAIN HITS MONTPELIER
(MPV) HARD WITH LIFR CONDITIONS IN BOTH CEILING AND VISIBILITY
WITH DENSE FOG. THINK IT WILL BE MORE STRATUS AND LESS FOG
TONIGHT, BUT THE END RESULT COULD BE THE SAME WITH A CLOUD DECK
JUST A FEW HUNDRED FEET ABOVE THE GROUND. FOR THURSDAY, THE
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS NOW OFF TO OUR WEST WILL
BE MORE OR LESS OVER THE AREA. KEPT IT VFR FOR VERMONT SIDE,
THOUGH MVFR VISIBILITIES AND CEILINGS WILL PROBABLY BE ACROSS
NORTHERN NEW YORK.

OUTLOOK 18Z THURSDAY THROUGH MONDAY...
18Z THUR 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...NASH
NEAR TERM...LOCONTO
SHORT TERM...LOCONTO
LONG TERM...NASH
AVIATION...NASH





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