000
FXUS61 KBTV 071148
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
648 AM EST WED JAN 7 2009
.SYNOPSIS...
A LONG-DURATION WINTER STORM WILL IMPACT THE NORTH COUNTRY TODAY
INTO EARLY THURSDAY. LOW PRESSURE WILL TRACK NORTHEASTWARD UP
THROUGH THE GREAT LAKES TODAY AND INTO THE SAINT LAWRENCE VALLEY TONIGHT.
A SECOND AREA OF LOW PRESSURE WILL DEVELOP EAST OFF THE NEW JERSEY
COAST AND THEN STRENGTHEN AS IT LIFTS NORTHEASTWARD INTO THE GULF
OF MAINE DURING TONIGHT. A MIX OF SNOW AND SLEET WILL IMPACT THE
REGION...WITH SOME FREEZING RAIN ACROSS SOUTH CENTRAL VERMONT THIS
AFTERNOON ASSOCIATED WITH A LAYER OF ABOVE FREEZING AIR ALOFT. THE
MIXED PRECIPITATION WILL CHANGE BACK TO SNOW EARLY TONIGHT BEFORE
DIMINISHING THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 512 AM EST WEDNESDAY...LIGHT SNOW HAS OVERSPREAD THE REGION
EARLY THIS MORNING. HOWEVER...SOME WARMER AIR ALOFT IS NOT THAT
FAR AWAY. COMPOSITE RADAR LOOP SHOWING SOME BRIGHT BANDING ACROSS
EXTREME SOUTHERN VERMONT AND JUST TO THE NORTH OF ALBANY. THIS
CORRESPONDS TO THE CHANGE OVER OR MIXING WITH SLEET. ALREADY SLEET
BEING REPORTED AT ALBANY...AND INDICATIONS THAT PRECIPITATION HAS
CHANGED TO SLEET AT BENNINGTON VERMONT. THIS INDICATES THE WARMER
AIR ALOFT MOVING TOWARD THE REGION. EXPECTING SNOW TO MIX WITH OR
CHANGE TO SLEET THIS MORNING ACROSS SOUTHERN VERMONT...AND THEN
MIX WITH OR CHANGE TO SLEET OR FREEZING RAIN THIS AFTERNOON ACROSS
SOUTHERN VERMONT. BUFKIT FORECAST SOUNDINGS ALSO SHOWING THAT SNOW
WILL LIKELY MIX OR CHANGE TO A PERIOD OF SLEET ACROSS PORTIONS OF
NORTHERN AND CENTRAL VERMONT...AS WELL AS A PORTION OF THE
ADIRONDACKS EARLY THIS AFTERNOON. BUFKIT FORECAST SOUNDINGS
SUGGEST PRECIPITATION WILL STAY AS ALL SNOW ACROSS THE SAINT
LAWRENCE VALLEY. HAVE GONE A BIT BELOW MOS GUIDANCE FOR MAX
TEMPERATURES TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
AS OF 512 AM EST WEDNESDAY...ANY MIXED PRECIPITATION EARLY THIS
EVENING WILL CHANGE BACK TO ALL SNOW AS COLDER AIR ALOFT WORKS
BACK INTO THE REGION...WITH AN ADDITIONAL SNOW ACCUMULATION OF 1
TO 4 INCHES EXPECTED. THE SNOW WILL SLOWLY TAPER OFF TO SNOW
SHOWERS LATE TONIGHT...WITH SNOW SHOWERS CONTINUING INTO THURSDAY
AS THE REGION WILL BE UNDER CYCLONIC FLOW FROM THE DEPARTING LOW
PRESSURE AREA OVER THE CANADIAN MARITIMES. SNOW SHOWER ACTIVITY
WILL BEGIN TO WIND DOWN THURSDAY NIGHT...AND BE MAINLY CONFINED TO
THE HIGHER ELEVATIONS OF THE ADIRONDACKS AND GREEN MOUNTAINS. A
WEAK RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE
EASTERN GREAT LAKES BY FRIDAY AFTERNOON.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 325 AM EST WEDNESDAY... GRADUAL DEEPENING LONG WAVE TROF
OVER THE EASTERN US IS EXPECTED THIS PERIOD WITH SEVERAL SHORT
WAVES HELPING TO CARVE OUT THE TROF. EXACTLY WHEN AND HOW THIS
OCCURS IS NOT CERTAIN AT THIS POINT SO LEANED ON GFS ENSEMBLES FOR
WEATHER AND MOS FOR TEMPS.
THE FIRST SHORT WAVE SHOULD BRING A SURFACE LOW SOUTH OF THE AREA
OVER THE WEEKEND WITH SOME LIGHT SNOW. GFS/GFS ENSEMBLES A BIT
STRONGER AND FARTHER NORTH WHILE ECMWF IS FURTHER SOUTH AND WEAKER.
GFS ENSEMBLE MEAN A GOOD COMPROMISE.
MONDAY WE COULD BE BETWEEN SYSTEMS AS INDICATED IN THE ENSEMBLES
WHILE OPS GFS SHOWS ANOTHER SYSTEM WHICH SEEMS TO BE AN OUTLIER AT
THIS POINT.
ANOTHER LOW PRESSURE SYSTEM DEVELOPING OVER EASTERN NORTH AMERICA IN
RESPONSE TO DIGGING TROF ON TUE. AGAIN LOTS OF UNCERTAINTY WITH
THIS AS ECMWF BASICALLY HAS COLD ARTIC FROPA WITH A LOW IN ERN
CANADA WHILE GFS/ENSEMBLES HAVE A DEEPENING CYCLONE OVER THE GREAT
LAKES/NE. JUST KEPT A CHANCE OF SNOW IN THE FORECAST FOR THIS
BUT ANY SIG MOISTURE WITH THIS WOULD SEEM TO BE LACKING IN EITHER
CASE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 12Z THURSDAY...SATELLITE/RADAR SHOW PERIODS OF IFR/LIFR
POSSIBLE AT TIMES 12-18Z IN MODERATE TO HEAVY SNOW. SOME MIXING TO
SLEET 12-16Z KRUT AND FREEZING RAIN POSSIBLE BY 16Z WITH WARM AIR
ALOFT. SOME SLEET MAY REACH BTV AND MPV BY 18Z. THIS SHOULD BRING
SLIGHTLY HIGHER VSBYS AND CIGS BUT MOSTLY IFR. COLDER AIR STARTS
TO MOVE BACK INTO THE REGION THIS EVENING WITH ALL TAF SITES BACK
TO SNOW AND IFR CONDITIONS CONT THROUGH 12Z. WINDS E G25KT
EASTERLY AT KMSS IN ST. LAWRENCE VALLEY WIND CHANNELING AND SE
G25KT AT KRUT WITH GAP WINDS...OTHERWISE WINDS WILL GRADUALLY COME
AROUND TO W 10G20KT ALL SITES 6-12Z. ONE AREA OF LOW PRESSURE WILL
MOVE UP THE ST. LAWRENCE VALLEY TOWARDS KMSS AND ANOTHER MOVES
ALONG THE SOUTHERN NEW ENGLAND COAST.
12Z THURSDAY THROUGH SUNDAY...IFR WITH SNOW 12Z THU THROUGH 00Z FRI
WITH INCREASING NW UPSLOPE FLOW. MVFR/VFR FRIDAY UNDER HIGH
PRESSURE. IFR WITH SNOW/SNOW SHOWERS SAT/SUN AS LOW PRESSURE MOVES
SOUTH OF THE REGION.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WINTER STORM WARNING UNTIL 1 PM EST THURSDAY FOR VTZ001>012-
016>019.
NY...WINTER STORM WARNING UNTIL 1 PM EST THURSDAY FOR NYZ026>031-
034-035-087.
&&
$$
SYNOPSIS...SISSON
NEAR TERM...WGH
SHORT TERM...WGH
LONG TERM...SISSON
AVIATION...SISSON
