000
FXUS61 KBTV 272047
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
347 PM EST MON DEC 27 2010
.SYNOPSIS...
A POWERFUL WINTER STORM WILL MOVE ACROSS NOVA SCOTIA THIS EVENING
AND CONTINUE HEADING UP THROUGH THE CANADIAN MARITIMES OVERNIGHT.
A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION ON TUESDAY. AN
UPPER AIR DISTURBANCE WILL BRING SOME CLOUDS AND WIDELY SCATTERED
SNOW SHOWERS TO THE NORTH COUNTRY TUESDAY NIGHT INTO WEDNESDAY.
ANOTHER RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION THURSDAY
AND FRIDAY...ALONG WITH A TREND TOWARDS MILDER TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 343 PM EST MONDAY...967 MB LOW HEADING TOWARDS NOVA SCOTIA
THIS AFTERNOON WILL CONTINUE ITS TREK UP THRU THE MARITIMES
OVERNIGHT. SNOW SHOWERS CONTINUE ACROSS VERMONT AT THIS TIME...AND
WILL CONTINUE FOR THE BALANCE OF THE AFTERNOON BEFORE TAPERING OFF
THIS EVENING. ANY ADDITIONAL ACCUMULATIONS EXPECTED TO BE
MINOR...GENERALLY A DUSTING TO PERHAPS AS MUCH AS 2 INCHES. ONLY
CHANCE POPS CARRIED AFTER 00Z...DIMINISHING TO SLIGHT CHANCE AND
CONFINED TO NORTHEAST KINGDOM AFTER MIDNIGHT AS THE LOW PULLS
FURTHER AWAY AND DRIER AIR WORKS IN FROM THE WEST. SKIES HAVE BEEN
PARTLY TO MOSTLY SUNNY IN ST LWR VLY THIS PM...AND THIS CLEARING
TREND WILL OCCUR ACROSS REST OF THE FORECAST AREA OVERNIGHT...ALTHOUGH
CLOUDS WILL STUBBORNLY HANG ON IN NORTHEAST VERMONT AND UPSLOPE
FAVORED AREAS OF NORTHERN VERMONT DUE PERSISTENT NW FLOW. THIS NW
FLOW WILL BE ABATING SOME OVERNIGHT...SO STRONGEST WINDS (MAINLY
BTWN 30-35 MPH) WILL OCCUR FROM THE CHMPLN VLY EASTWARD THRU ABOUT
MIDNIGHT. THE STRONG WINDS THIS EVENING WILL CONTINUE TO PRODUCE
AREAS OF BLOWING/DRIFTING SNOW AND REDUCED VSBYS. MIN TEMPS
EXPECTED TO BE WITHIN A FEW DEGREES OF ZERO ACROSS MUCH OF THE
AREA TONIGHT...WITH WIND CHILLS MAINLY BETWEEN -10 AND -20F. NO
WIND CHILL ADVISORIES ISSUED AT THIS TIME...AS VALUES BELOW -20F
MOSTLY CONFINED TO THE HIR ELEVATIONS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 343 PM EST MONDAY...NORTHWEST FLOW CONTINUES ACROSS THE REGION
ON TUESDAY...ALTHOUGH AIRMASS QUITE DRY SO EXPECT PARTLY TO
MOSTLY SUNNY SKIES AS WEAK RIDGING ATTEMPTS TO BUILD IN FROM THE
WEST DURING THE AFTERNOON AND EVENING HOURS. COULD BE SOME LIGHT
SNOW SHOWERS RETURNING...MAINLY TO THE SAINT LAWRENCE VALLEY
AND THE ADIRONDACKS LATER TUESDAY NIGHT INTO WEDNESDAY AS FLOW
BECOMES MORE SOUTHWESTERLY AND WEAK UPPER AIR DISTURBANCE MOVES
ACROSS THE REGION. MOISTURE LACKING HOWEVER...SO NOTHING
APPRECIABLE IN WAY OF SNOWFALL EXPECTED. RIDGE OF HIGH PRESSURE
THEN BUILDS EAST FROM THE GREAT LAKES WEDNESDAY NIGHT BRINGING
CLEARING SKIES.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 320 PM EST MONDAY...NO BIG CHANGES IN 12Z GUIDANCE SUITE FOR
THE UPCOMING NEW YEARS HOLIDAY WEEKEND. ALL IN ALL, IT STILL
APPEARS THAT WE'LL SEE A DIFFERENT SYNOPTIC PATTERN IN PLACE
COMPARED TO THE ONE WE'VE BEEN IN. THIS FORECAST PERIOD WILL START
OUT DRY AND CLEAR AS HIGH PRESSURE SITS OVERHEAD. TEMPERATURES
SHOULD BE SEASONABLY COOL THURSDAY. HIGH PRESSURE STARTS TO MOVE
EAST OF HERE THURSDAY NIGHT, ALLOWING SOME WARM AIR ADVECTION TO
COMMENCE, ESPECIALLY ACROSS NORTHERN NEW YORK. HUNG CLOSE TO
GUIDANCE, SHOWING COLDEST TEMPERATURES (SINGLE DIGITS) ACROSS
NORTHEAST VERMONT, WITH TEMPS IN THE TEENS/LOWER 20S IN NORTHERN
NY. HOWEVER IF THINGS PROGRESS A BIT SLOWER, EXCELLENT RADIATIONAL
COOLING CONDITIONS WOULD BE IN PLACE, LEADING TO TEMPERATURES
LOWER THAN CURRENTLY PROJECTED. FRIDAY SHOULD BE ANOTHER DRY AND
MOSTLY SUNNY DAY THANKS TO RIDGING ALOFT. TEMPERATURES ABOUT 5-10F
HIGHER THANKS TO A DEVELOPING SOUTHWEST FLOW.
LOOKS LIKE THE SYNOPTIC PATTERN WILL BE GOING TO ONE WHERE LOW
PRESSURE SYSTEMS WILL BE FORMING ACROSS THE CENTRAL US AND
TRACKING NORTHEAST BUT STAYING TO OUR WEST. THAT MEANS WE'LL BE
GETTING INTO THE WARM SECTOR OF STORMS AS THEY APPROACH. GUIDANCE
IS PRETTY SIMILAR AND CONSISTENT WITH SHOWING A PRETTY STRONG LOW
PRESSURE SYSTEM MOVING ACROSS THE WESTERN GREAT LAKES TO NEAR
HUDSON BAY SATURDAY INTO SUNDAY. A COLD FRONT WILL MOVE ACROSS THE
REGION SATURDAY NIGHT AND EARLY SUNDAY. AHEAD OF THE FRONT, WE
SHOULD SEE QUITE MILD TEMPERATURES ON SATURDAY ALONG WITH
INCREASING CLOUDS. WENT A COUPLE OF DEGREES ABOVE GUIDANCE, BUT
WITH SNOWPACK ON THE GROUND, TEMPERATURES WILL BE TRICKY. COLDER
TEMPERATURES MAY BE HARD TO SCOUR OUT IN THE NORTHEAST KINGDOM,
WHILE WE MAY SEE GUSTY SOUTH/SOUTHWEST WINDS DEVELOP IN THE
CHAMPLAIN AND ST LAWRENCE VALLEYS ENHANCING THE MIXING OF THE WARM
TEMPERATURES ALOFT (~6C AT 925MB AND ~8C AT 850). IN THE END, I
DID SHADE A DEGREE OR TWO ABOVE MOS GUIDANCE IN THE CHAMPLAIN & ST
LAWRENCE VALLEYS (TO SHOW MID-UPPER 40S), AND STAYED CLOSE IN THE
NORTHEAST KINGDOM (NEAR 40). MOUNTAIN SUMMITS WILL BE WELL INTO
THAT ABOVE FREEZING AIR.
COLD FRONT COMES THROUGH SOMETIME SATURDAY NIGHT/EARLY SUNDAY.
TIMING WILL MAKE A BIG DIFFERENCE IN OVERNIGHT LOWS. TRIED TO SHOW
A COLDER WEST-WARMER EAST SITUATION. LOOKS LIKE PRECIP WILL BE
PREDOMINATELY RAIN. THERE IS AN OUTSIDE CHANCE OF SOME MIXED
PRECIP FOR SHELTERED HOLLOWS IF THEY NEVER GET THE WARM AIR.
HOWEVER, THIS FAR OUT WITH ALL THE UNCERTAINTY IN TEMPERATURES,
JUST PLAYED IT A RAIN/SNOW DEAL DEPENDING ON SURFACE TEMPERATURE.
AS WE GET CLOSER TO THE EVENT, WE CAN ADD MORE SCIENCE TO THE
FORECAST AND TAKE THE TIME TO ADD THE P-TYPE DETAILS AS NEEDED.
SUNDAY AND MONDAY LOOK TO BE POST-FRONTAL NORTHWEST FLOW REGIMES.
PAINTED IN SOME HIGHER POPS ACROSS THE HIGHER TERRAIN OF THE
NORTH. NO REAL COLD AIR EXPECTED IN THE WAKE OF THE STORM AS THE
OVERALL FLOW IS MORE ZONAL, RESULTING IN A MODIFIED PACIFIC
AIRMASS TO SPREAD ACROSS THE COUNTRY. THUS, LOOKING AT
TEMPERATURES SUNDAY AND MONDAY TO BE NEAR NORMAL.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
THROUGH 18Z TUESDAY...ALTHOUGH CONDITIONS IN MOST AREAS ARE
IMPROVING, NORTHERLY FLOW DOWN THE CHAMPLAIN VALLEY CONTINUES TO
BE A PAIN IN THE REAR, RESULTING IN CONTINUED DEVELOPMENT OF AREAS
OF SNOW. SOME OF THE SNOW IS BRIEFLY HEAVY, RESULTING IN
VISIBILITIES OF 1/4-1/2SM. FOR BETTER OR WORSE, THE ONLY TERMINAL
REALLY IMPACTED BY THIS FEATURE IS KBTV. MEANWHILE, VFR CONDITIONS
ARE DEVELOPING ACROSS NORTHERN NY. A MIX OF MVFR CEILINGS WITH IFR
VISIBILITIES ARE STILL BEING REPORTED AT OTHER VERMONT TERMINALS
(KRUT AND KMPV). SURFACE WINDS CONTINUE TO GUST INTO THE 20-30KT
RANGE AT MANY SITES. BLOWING SNOW CAN BE EXPECTED AT LOCATIONS
ACROSS VERMONT.
DESPITE THE PESKY SNOW IN THE CHAMPLAIN VALLEY, ANTICIPATE
IMPROVING CONDITIONS AREA WIDE BY THIS EVENING AS THE MAJOR STORM
PUSHES FARTHER OFF THE EAST COAST, ALLOWING HIGH PRESSURE TO START
BUILDING IN.
EXPECT VFR CONDITIONS AT ALL TERMINALS TO BE THE RULE OVERNIGHT
AND TUESDAY. MAY SEE SOME SURFACE WIND GUSTS IN THE 15-25KT RANGE
AFTER 15Z TUESDAY.
OUTLOOK 18Z TUESDAY THROUGH SATURDAY...
PERHAPS SOME MVFR WITH LIGHT SNOW SHOWERS ACROSS NORTHERN NY
TUESDAY NIGHT. PERHAPS SOME MVFR CEILINGS LATE FRIDAY AND
SATURDAY. OTHERWISE VFR AREAWIDE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RJS
NEAR TERM...RJS
SHORT TERM...RJS
LONG TERM...NASH
AVIATION...NASH
