451 
FXUS61 KBTV 110223
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1023 PM EDT FRI MAY 10 2013

.SYNOPSIS...
THE COMBINATION OF A SLOW MOVING COLD FRONT AND A WAVE OF LOW
PRESSURE WILL BRING SHOWERS TO THE REGION TONIGHT INTO SATURDAY. 
BEHIND THIS SYSTEM...MUCH COOLER AIR ARRIVES ACROSS THE REGION BY
SUNDAY INTO EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 8 AM SATURDAY MORNING/...
AS OF 1019 PM EDT FRIDAY...AGAIN, JUST MINOR TWEAKS TO THE GRIDDED
FORECAST DATABASE. SHOWERS CONTINUE TO APPROACH FROM THE WEST,
WITH SOME ALREADY INTO THE ST LAWRENCE VALLEY AND WESTERN 'DACKS.
SHOULD BE GETTING INTO VERMONT A BIT AFTER MIDNIGHT. LATEST
LIGHTNING DATA SHOWS PRETTY MINIMAL ACTIVITY, MAINLY SOME IN-CLOUD
FLASHES, SO KEPT TO THE IDEA OF ONLY A SLIGHT CHANCE OF A RUMBLE
OF THUNDER UNTIL MIDNIGHT FOR NORTHERN NEW YORK. COULD BE SOME
PATCHY FOG, ESPECIALLY IN EASTERN VERMONT/CONNECTICUT RIVER
VALLEY, WHERE WINDS ARE LIGHT AND THERE ARE A FEW HOLES IN THE
CLOUDS. TEMPERATURES ARE IN THE UPPER 50S TO LOWER 60S AT THIS
TIME, AND ARE NOT EXPECTED TO CHANGE MUCH OVERNIGHT DUE TO THE
CLOUDS, SHOWERS AND INCREASING LOW LEVEL JET. 

PREVIOUS DISCUSSION....
MINOR UPDATES EARLY THIS EVENING, BASED PRIMARILY ON LATEST RADAR
TRENDS. AS EXPECTED THE THUNDERSTORMS WELL TO OUR SOUTHWEST ARE
CONGEALING INTO A LARGER AREA OF RAIN/SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS. TOOK NOTE OF THE THUNDERSTORMS WHICH PERSISTED AS
THEY WENT ACROSS THE COLD WATERS OF LAKE ONTARIO AND NOW MOVING
INTO THE ST LAWRENCE VALLEY AS A SIGNAL OF SOME ELEVATED
INSTABILITY. 18Z NAM SHOWED THIS AREA WITH NEGATIVE SHOWALTERS, SO
LEANED ON IT FOR A SHORT TERM PREDICTION WHICH INDICATES SOME
ELEVATED INSTABILITY WILL BE INTACT EVEN AT 06Z AND BY THAT TIME
BE INTO VERMONT. PURE EXTRAPOLATION PUTS THAT BATCH OF
PRECIPITATION MOVING INTO THE ADIRONDACKS BY 0130Z AND THEN INTO
THE CHAMPLAIN VALLEY ABOUT 03-04Z. THIS IS A SLIGHT SPEEDING UP
FROM PREVIOUS FORECAST, BUT NOT BY MUCH. ALSO ADDED MENTION OF
THUNDERSTORMS FOR ALL OF NORTHERN NY AND INTO THE FAR WESTERN
EDGES OF VERMONT THROUGH ABOUT 04Z. DESPITE THE ELEVATED
INSTABILITY, I DO THINK MUCH OF THE CONVECTION WILL "MUSH OUT",
BUT WILL RE-EVALUATE IT IN A COUPLE OF HOURS.

TEMPERATURES WON'T BE GOING MUCH ANYWHERE FROM WHERE THEY ARE NOW.
GOING TO BE A WARM/MUGGY NIGHT.

SOUTHERLY LOW LEVEL JET WILL ALSO BE PICKING UP AFTER MIDNIGHT,
AND COULD GET A LITTLE BREEZY IN THE CHAMPLAIN VALLEY BUT THAT WAS
ALREADY ACCOUNTED FOR IN THE FORECAST.


&&

.SHORT TERM /8 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 354 PM EDT FRIDAY...AFOREMENTIONED COLD FRONT WILL MAKE ITS
WAY SLOWLY EASTWARD ACROSS THE FORECAST AREA DURING SATURDAY. SLOW
EASTWARD PROGRESS DUE TO UPPER FLOW ALMOST PARALLEL TO SURFACE
BOUNDARY. DRY SLOT DOES WORK INTO NORTHERN NEW YORK DURING THE
MORNING...WHERE BULK OF RAIN WILL END BY MIDDAY. IN VERMONT
HOWEVER...THREAT OF SHOWERS CONTINUES FOR MUCH OF THE
DAY....ESPECIALLY EAST OF THE GREENS. MARGINAL INSTABILITY
INDICATED IN ADVANCE OF THE FRONT...SO HAVE LEFT IN SLIGHT CHANCE
OF THUNDER. RAINFALL TOTALS THROUGH SATURDAY ACROSS THE REGION
EXPECTED TO RANGE FROM 0.50 TO 1.50 INCHES. MAX TEMPS SATURDAY
WILL BE IN THE UPPER 60S AND LOWER 70S.

SHOWERS WILL COME TO END SATURDAY NIGHT AS FRONT DEPARTS. 
CLOUDS WILL ALSO SLOWLY DIMINISH IN COVERAGE AS A DRY SLOT MOVES
INTO THE NORTH COUNTRY. LARGE UPPER LOW MOVES INTO THE REGION
SUNDAY...WHICH WILL BE ACCOMPANIED BY SOME CLOUDS AND WIDELY
SCATTERED SHOWERS. COLDER TEMPERATURES WILL ALSO FILTER IN
SATURDAY NIGHT INTO SUNDAY...WITH HIGHS SUNDAY EXPECTED TO BE IN
THE UPPER 50S AND LOWER 60S. WITH THE UPPER LOW MOVING ACROSS THE
AREA SUNDAY NIGHT...THERE WILL BE CHANCE FOR A FEW MORE LIGHT
SHOWERS...ESPECIALLY ACROSS NORTHERN NY. COULD BE COLD ENOUGH FOR
A FEW SNOW SHOWERS IN NORTHERN ADIRONDACKS WHERE TEMPS WILL DIP
INTO THE UPPER 20S. ELSEWHERE...LOWS WILL BE MAINLY IN THE 30S.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 348 PM EDT FRIDAY...NOT MUCH OVERALL CHANGE FROM PREVIOUS
FORECAST THINKING AS THE FORECAST AREA WEATHER WILL BE DOMINATED
BY UPPER LEVEL LOW PRESSURE FOR THE FIRST HALF OF THE WEEK...AND
RIDGING FOR THE REMAINDER. STARTING MONDAY...UPPER LEVEL TROUGH
ENTERS THE NORTHEAST BEHIND A DEPARTING COLD FRONT WITH
ABNORMALLY LOW TEMPS FOR MID-MAY USHERING INTO THE REGION. COLD
POOL ALOFT COMBINED TO STEEP LOW LEVEL LAPSE RATES SHOULD PRODUCE
SOME AFTERNOON SHOWERS...WITH HIGH TEMPS ACROSS THE REGION ONLY
IN THE 50S. BY MONDAY NIGHT...SURFACE HIGH PRESSURE BUILDS INTO
THE AREA WHILE THE UPPER TROUGH AND COLD AIR ALOFT IS SLOWER TO
MOVE OUT. THUS...WHILE PRECIP CHANCES DROP OFF...OVERNIGHT LOWS
WILL BE RATHER CHILLY IN THE UPPER 20S TO MID 30S WITH AREAS OF
FROST LIKELY.

UPPER TROUGH SLOWLY PROGRESSES EAST TUESDAY/TUESDAY NIGHT WITH A
SLOW WARMING TREND EXPECTED BY MID-WEEK AS AN UPPER RIDGE TRIES
TO BUILD INTO THE NORTHEAST. RIDGE NEVER REALLY FULLY MAKES IT IN
THOUGH...SHIFTING SOUTH OF THE CWA WITH THE NORTH COUNTRY
SITUATED ON THE NORTHERN PERIPHERY OF THE RIDGE SETTING UP A NICE
UPPER LEVEL THERMAL BOUNDARY. THIS BOUNDARY WILL BE THE FOCUS FOR
SHOWER AND THUNDERSTORM DEVELOPMENT FOR WEDNESDAY NIGHT THROUGH
FRIDAY. HIGHS THROUGH THIS PERIOD WARM BACK TOWARDS SEASONAL
NORMALS AND SLIGHTLY ABOVE WITH HIGHS GENERALLY IN THE UPPER 60S
TO LOWER 70S...AND LOWS IN THE 40S/50S.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 00Z SUNDAY...WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS
OVER WESTERN AND WEST-CENTRAL NEW YORK THIS EVENING WILL MOVE
NORTHEAST AND OVERSPREAD OUR AREA BETWEEN 01Z AND 04Z. BEST
POTENTIAL FOR ANY THUNDER WILL BE OVER NORTHERN NEW YORK. EXPECT
CEILINGS AND VISIBILITIES TO LOWER INTO THE MVFR CATEGORY ONCE THE
SHOWERS AND STORMS MOVE...ESSENTIALLY FROM 04Z THROUGH ABOUT
14Z...THEN VISIBILITIES WILL GO BACK INTO THE VFR CATEGORY WITH
CEILINGS SLOWLY RISING INTO THE VFR CATEGORY SATURDAY AFTERNOON.
WINDS WILL BE LIGHT AND VARIABLE...THEN BECOME MORE SOUTHERLY
AFTER 04Z WITH GUSTS IN THE 10 TO 20 KNOT RANGE BETWEEN 06Z AND
12Z BEFORE GRADUALLY TAPERING OFF AND BECOMING MORE SOUTHWEST.

OUTLOOK 00Z SUNDAY THROUGH WEDNESDAY...

00Z SUNDAY THROUGH 12Z SUNDAY...VFR UNDER DRY SLOT.

12Z SUNDAY THROUGH 00Z TUESDAY...GENERALLY VFR WITH ISOLATED AFTERNOON
SHOWERS POSSIBLE UNDER UPPER LEVEL LOW.

00Z TUESDAY THROUGH WEDNESDAY...VFR UNDER HIGH PRESSURE.

&&

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

&&

$$
SYNOPSIS...RJS
NEAR TERM...NASH
SHORT TERM...RJS
LONG TERM...LAHIFF
AVIATION...EVENSON/LAHIFF