FXUS61 KBTV 100556
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1256 AM EST THU DEC 10 2009
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN CONTINUES IN THE NORTH COUNTRY. A COLD
FRONT WILL MOVE THROUGH THE FORECAST AREA THIS EVENING BRINGING
ANOTHER CHANCE OF SHOWERS AND MAINTAINING GUSTY WINDS THROUGH THIS
EVENING. COLDER AIR WILL MOVE INTO THE NORTH COUNTRY LATER
TONIGHT...WITH THE POTENTIAL FOR SOME ONTARIO LAKE EFFECT SNOW
SHOWERS...IN ST LAWRENCE VALLEY AND THE ADIRONDACKS. ADDITIONAL LAKE
EFFECT SNOW SHOWERS WILL OCCUR TOMORROW...MAINLY IN THE ADIRONDACKS
AND PORTIONS OF THE WESTERN GREENS. THEN LATER TOWARD THE WEEKEND
EXPECT THE COLDEST AIRMASS THUS FAR OF THE SEASON.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1008 PM EST WEDNESDAY...ANOTHER MINOR UPDATE TO THIS EVENING'S
PACKAGE...MAINLY TO REFLECT LATEST EXPECTED TRENDS IN TEMPS
OVERNIGHT AND TO INCREASE POPS SLIGHTLY THROUGH LATE EVENING BASED
OFF CURRENT RADAR TRENDS. COMPLEX OCCLUDED BNDRY IN PROCESS OF
CROSSING THE AREA CURRENTLY...WITH STRONGER COLD FRONT PUSHING
RAPIDLY EASTWARD ACROSS CENTRAL NY. WITH DECENT SOUTH/SOUTHWESTERLY
MIXED BNDRY LYR FLOW EXPECTED TO CONTINUE OVERNIGHT...CAA PROCESSES
WILL BE OFFSET SOMEWHAT INITIALLY...SO EXPECTING VALUES TO FALL LATE
ACROSS OUR NRN NY ZONES...THOUGH HOLD NEARLY STEADY IN THE 29-35
ACROSS VT. AS COLDER 850 MB TEMPS RACE IN ALOFT...ANY LINGERING
MIXED P-TYPE CONCERNS THIS EVENING SHOULD CHANGE TO ALL SHSN AFTER 4
AM OR SO. WILL MAINTAIN IDEA THAT ANY ACCUM SHOULD REMAIN LIGHT AND
GENERALLY LESS THAN 2 INCHES THROUGH EARLY MORNING...THOUGH HEAVIER
LAKE EFFECT SNOWS WILL BE IN THE PROCESS OF CRANKING UP LATE ACROSS
TRADITIONAL SNOWBELTS OF SRN ST LAWRENCE/SRN FRANKLIN COUNTIES. REST
OF FCST IN GOOD SHAPE AND OTHER THAN ABOVE CHGS...NO OTHER
ADJUSTMENTS NEEDED ATTM. HAVE A GOOD NIGHT.
PRIOR DISCUSSION...THE HEAVIEST ORGANIZED BAND OF PRECIPITATION HAS
MOVED OUT OF THE FORECAST AREA. BUT A COLD FRONT APPROACHING FROM
THE SOUTHWEST WILL KEEP SHOWERS IN THE FORECAST TONIGHT. WITH STRONG
SOUTHERLY FLOW...WE ARE SEEING TEMPERATURE CONTINUE TO CLIMB THROUGH
THE EVENING. THIS STRONG FLOW AND A TIGHT PRESSURE GRADIENT WILL
ALSO MAINTAIN GUSTY SOUTHEASTERLY AND SOUTHERLY WINDS IN THE NORTH
COUNTRY. WARNING LEVEL WINDS WILL CONTINUE ALONG THE WESTERN SPINE
OF THE GREEN MOUNTAINS THROUGH THE EVENING HOURS AND SUBSIDE SLOWLY
THIS EVENING AS THE WINDS SHIFTS MORE SOUTH AND SOUTHWESTERLY...
WHICH EQUATES TO LESS FAVORABLE DOWN SLOPE DIRECTION...WITH THE
FRONTAL PASSAGE. THOUGH THESE WINDS WILL NOT COMPLETELY ABATE...AS
THE PRESSURE GRADIENT CONTINUES TO BE STRONG. THIS STRONG GRADIENT
AND OUR ABILITY TO MIX NOW THAT PRECIP HAS ENDED...IS THE REASON WE
ARE SEEING SUCH GUSTY WINDS THIS EVENING IN THE CHAMPLAIN VALLEY.
FOR THE REMAINDER OF THE NIGHT PRECIPITATION WILL BE MUCH MORE
SCATTERED THAN THE WIDESPREAD SNOW WE EXPERIENCED EARLIER. WHILE
MUCH OF THE FORECAST AREA HAS TEMPERATURES ABOVE THE FREEZING
MARK...SOME LOCAL AREAS ARE STILL AT OR BELOW FREEZING AND THUS THE
SLIGHT POTENTIAL FOR ISOLATED POCKETS OF FREEZING RAIN EXISTS
ESPECIALLY IN THE LOW LYING MTN VALLEYS. BUT AS MENTIONED
ABOVE...TEMPERATURES WILL CONTINUE TO CLIMB THROUGH THIS EVENING.
BEHIND THE FRONT A SUBSTANTIALLY COLDER AIRMASS MOVES INTO THE
NORTH COUNTRY. THUS WE WILL SEE OUR TEMPERATURES COOL MARKEDLY
TOWARD MORNING. AS THIS COLD AIR MOVES OVER LAKE ONTARIO IT WILL
DEVELOP LAKE EFFECT SHOWERS WHICH...WITH SOUTHWESTERLY FLOW...WILL
IMPACT THE ST. LAWRENCE VALLEY...THEN THE ADIRONDACKS AFTER
MIDNIGHT. WE ARE SEEING A HINT AT THIS NOW WITH SHOWERS IN WESTERN
NEW YORK AND ALSO PENN. THE ATMOSPHERE IS MUCH MORE UNSTABLE IN
THOSE LOCATIONS THAN OVER THE NORTH COUNTRY...SO SHOWERS THIS
EVENING WILL DISSIPATE AS THEY MOVE IN OUR DIRECTION.
WINDS WILL SHIFT TO A MORE WESTERLY DIRECTION TOMORROW AS A RIDGE
OF HIGH PRESSURE TRIES TO BUILD BEHIND THE SYSTEM. AS SUCH THE
GRADIENT WILL BE FAIRLY TIGHT AND WE WILL CONTINUE TO SEE GUSTY
WINDS TO ABOUT 30-40 MPH ACROSS THE FORECAST AREA. WITH THE UPPER
AND MID LEVEL FLOW REMAINING SOUTHWESTERLY...WE WILL CONTINUE SEE
SOME LAKE EFFECT SNOWS DEVELOP OFF OF LAKE ONTARIO...AND PROPAGATE
MAINLY INTO THE ADIRONDACKS. TOWARD AFTERNOON...AS OUR FLOW BECOMES
MORE WESTERLY... THESE SNOWS WILL ALSO PROPAGATE TOWARD THE WESTERN
SLOPES OF THE GREEN MOUNTAINS. WE COULD SEE A FEW INCHES OF SNOW IN
THE DACKS AND CENTRAL GREENS TOMORROW...AND WIDELY SCATTERED SNOW
SHOWERS ELSEWHERE. AS THE COLD AIRMASS CONTINUES TO WORK INTO THE
FORECAST AREA WE WILL NOT SEE MUCH OF A WARM UP TOMORROW. IN FACT
TEMPERATURES WILL REMAIN NEARLY FLAT FROM THE MORNING LOWS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
AS OF 239 PM EST WEDNESDAY...
HIGH PRESSURE RIDGE SETS UP OVER THE MIDWEST/SOUTHERN PORTIONS OF
THE COUNTRY DURING THIS TIME. THIS WILL ALLOW FOR WINDS OVER THE
AREA TO REMAIN MAINLY FROM THE WNW. WIND FLOW SETS UP LK EFFECT BAND
OFF OF LK ONTARIO...THAT WILL MV FROM N NY...SOUTH INTO CENTRAL VT
OVER THE 36 HR PERIOD. BAND OF SNOW WILL BE FOCUSED OVER SOUTHERN
PORTIONS OF THE ST LAW VALLEY/DACKS AND SHIFT INTO CENTRAL VT W/
HIGHEST AMTS CLOSEST TO LK ONTARIO. W/ LITTLE CHANGE IN WND FLOW
HAVE KEPT CLOSE TO MDL GUIDANCE NUMBERS FOR TEMPS
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
AS OF 239 PM EST WEDNESDAY...RIDGE TO OUR SOUTH WILL LIFT
NORTHWARD DURING THIS TIME...ALLOWING FOR CLRING SKIES. SOME --SW
POSSIBLE FOR NE VT W/ NW FLOW...BUT DO EXPECT WINDS TO SUBSIDE AS
RIDGE CRESTS OVER AREA. ALSO LK EFFECT BAND FALLS APART AS WELL SO
POSSBL TO SEE LINGERING --SW OVER EXTREME SOUTHERN PORTIONS OF
CWA/VT BFR IT TAPERS OFF DURING THE MORNING HRS. TEMPS WILL DROP
GOING INTO SAT NGT AS SKIES CLR W/ CALM WINDS. HAVE GONE BLW MDL
NUMBERS FOR OVERNGT LOWS. RIDGE WILL SLIP OFFSHORE TOWARDS SUN
MORNING ALLOWING FOR SSW WINDS TO WORK INTO PORTIONS OF THE ST LAW
VALLEY AHEAD OF NEXT SYSTEM. NO PRECIP EXPECTED OVERNGT...BUT INCR
CLD COVER FOR FAR W CWA. NEXT SFC LOW TO AFFECT THE NORTH COUNTRY
WILL BUILD ACROSS THE CWA BY SUN. EXPECTING QPF TO BE LGT BASED ON
SFC LOW TRACK TO THE N...BUT WITH CD POOL OF 850 TEMPS DROPPING
DOWN TO -22C/-26C BY EVENING FROM DAY HIGHS NEAR -8C. POTENTIAL
FOR SNOW SQUALLS/FLASH FREEZE AS THIS PUSHES E...ESPECIALLY FOR
NORTHERN PORTIONS OF THE CWA. W/ THIS FROPA...WINDS SHIFT TO THE
NNW ALLOWING FOR LEFTOVER UPSLOPE -SW MONDAY MORNING...CLRING BY
MDDAY AS HIGH PRESSURE BUILDS E OVER THE AREA AND REMAINING INTO
TUESDAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
THROUGH 06Z FRIDAY...WINDS WILL BE AN ISSUE OVER THE AREA BETWEEN
12Z AND 00Z AS WINDS WILL INCREASE FROM THE WEST AND SOUTHWEST.
EXPECT SUSTAINED WINDS IN THE 10 TO 20 KNOT RANGE WITH GUSTS IN
THE 35 TO 45 KNOT RANGE...ESPECIALLY OVER NORTHERN NEW YORK.
EXPECT SOME LAKE EFFECT SNOWS TO IMPACT KSLK AS WELL WITH IFR
CONDITIONS IN SNOW AND BLOWING SNOW BETWEEN 12Z AND 00Z.
ELSEWHERE...LOOKING AT VFR CONDITIONS WITH RESPECT TO CEILINGS AND
VISIBILITIES WITH ONLY BRIEF PERIODS OF MVFR CONDITIONS.
06Z FRIDAY THROUGH MONDAY...GUSTY WINDS CONTINUE LATE THURS NITE
THRU FRIDAY AS LOW PRESSURE SLOWLY DEPARTS. EXPECT WEST WINDS
15-25 KTS WITH GUSTS 30-35 KTS ALONG WITH SCT SNOW SHWRS PRODUCING
LOCALIZED IFR CONDITIONS...ESPECIALLY AT KSLK. MAINLY VFR ON
SAT/SAT NITE AS RIDGE OF HIGH PRESSURE MOVES ACRS THE REGION.
AREAS OF MVFR IN SNOW SHOWERS SUNDAY INTO MONDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...AMF
NEAR TERM...AMF/JMG
SHORT TERM...AMF
LONG TERM...JN
AVIATION...EVENSON/RJS
