FXUS61 KBTV 151751
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1251 PM EST TUE DEC 15 2009
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE OVER THE CHAMPLAIN VALLEY WILL MOVE
NORTHEAST INTO NORTHERN MAINE BY THIS EVENING. THIS LOW WILL BRING
AN ARCTIC COLD FRONT THROUGH THE REGION THIS MORNING WITH A FEW
SHOWERS. SIGNIFICANTLY COLDER AIR WILL MOVE INTO THE NORTH COUNTRY
BEHIND THIS FRONT WITH BELOW COLD BLUSTERY CONDITIONS EXPECTED
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1109 AM EST TUESDAY...925 MB TEMPERATURES STILL ABOVE
FREEZING FROM THE EASTERN ADIRONDACKS EASTWARD ACROSS VERMONT.
WILL CONTINUE TO KEEP IN A CHANCE OF RAIN SHOWERS IN THROUGH THE
DAY FROM THE CHAMPLAIN VALLEY EASTWARD. EXPECTING ANY RAIN SHOWERS
WILL CHANGE TO SNOW SHOWERS LATE THIS AFTERNOON ACROSS THE
CHAMPLAIN VALLEY AND THE REMAINDER OF VERMONT...AS COLDER AIR
ALOFT MOVES INTO THE REGION. SNOW SHOWERS ARE ALREADY OCCURRING IN
THE SAINT LAWRENCE VALLEY OF NORTHERN NEW YORK AS THE COLDER AIR
ALOFT HAS MOVED IN THERE. WILL ALSO KEEP SOME PATCHY FOG IN AS
WELL FOR THE REMAINDER OF TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
AS OF 431 AM EST TUESDAY...THE POTENTIAL FOR SCATTERED SHOWERS
CONTINUES INTO THE EVENING...BUT WITH COLD AIR
ADVECTION...MOISTURE IN THE DENDRITIC ZONE WILL ALLOW FOR PRECIP
TO FALL IN THE FORM OF SNOW SHOWERS. BRIEFLY THIS EVENING THE
ADIRONDACKS AND PORTIONS OF THE NORTHERN GREENS COULD SEE BIT OF
LAKE SNOW SHOWER WITH THE COLD AIR ADVECTION PRIOR TO THE PASSING OF
THE UPPER TROUGH... AS THERE WILL BE A BRIEF OPEN DOOR OF
SOUTHWESTERLY FLOW. BUT...THE PASSING OF THE UPPER TROUGH BRINGS A
MORE WEST TO NORTHWESTERLY FLOW ACROSS THE REGION BEFORE
MIDNIGHT...WHICH WOULD PUT AN END TO ANY SUCH SHOWERS IN OUR AREA.
THIS NORTHWESTERLY FLOW WILL BRING MUCH DRYER AND COLDER AIR INTO
THE NORTH COUNTRY...THUS ANTICIPATING SOME BREAKS IN THE CLOUDS BY
MORNING. TEMPERATURES WILL FALL RAPIDLY THROUGH THE EVENING AND
NIGHT INTO THE TEENS AND SINGLE DIGITS.
AFTER THIS EVENING THE FOCUS SHIFTS FROM PRECIPITATION POTENTIAL TO
WIND AND COLD TEMPERATURES. AS THE SURFACE LOW PASSES TO OUR EAST
OVER THE CANADIAN MARITIMES...AND STRONG HIGH PRESSURE BEGINS TO
BUILD OVER THE OHIO VALLEY...THE PRESSURE GRADIENT WILL TIGHTEN
CONSIDERABLY OVER THE FORECAST AREA. ANTICIPATE NNW GUSTS OF 25
TO 35 MPH THOUGH MUCH OF THE NORTH COUNTRY. THIS WILL BRING SUBZERO
WINDCHILL TEMPERATURES IN THE DACKS AND NORTHEAST KINGDOM OF VT
TOWARD WEDNESDAY MORNING. TEMPERATURES WEDNESDAY WILL RUN ABOUT
8-10 DEGREES BELOW NORMAL. AS WINDS PERSIST AND TEMPERATURES
CONTINUE TO DROP WEDNESDAY NIGHT...SUBZERO WIND CHILL TEMPERATURES
ARE EXPECTED THROUGH OUT THEN NORTH COUNTRY WEDNESDAY NIGHT INTO
THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 310 AM EST TUESDAY...NO BIG WX SYSTEMS TO AFFECT THE NORTH
COUNTRY THRU THE EXTENDED PERIOD. MDLS BRING STAGNANT UPPER LOW
OVER THE CANADIAN MARITIMES THURSDAY NIGHT ON INTO FRIDAY...BACK WEST
ACROSS THE GREAT LKS REGION THRU THE WEEKEND...THEN BACK EAST
AGAIN FOR NEXT MONDAY AND TUESDAY. THIS PATTERN IS A BIT SLOWER IN
ECMWF VERSUS GFS...BUT GENERAL TREND THE SAME. WK SFC RIDGE DOES
TRY TO BUILD OVER THE AREA DURING THIS TIMEFRAME...BUT CWA WILL
SEE SL CHANCE FOR -SW AS UPPER LOW RETROGRADES TO THE GREAT LKS.
BULK OF PRECIP TO REMAIN ALONG THE OUTER TRACK OF THE
LOW(PINWHEELING AROUND IT)...WITH THE NORTHEAST REGION ON THE
DRIER SIDE. CD AIRMASS WILL WRAP AROUND CIRCULATION FOR FIRST HALF
OF EXTENDED...WHICH WILL TREND TEMPS NEARLY 10 DEGREES BLW NORMAL.
BY THE LATTER HALF...W/ UPPER LOW OVER THE GREAT LKS...SOME WAA
WILL WORK INTO AREA THAT LIFT OUT SOME HIR TEMPS...BUT WILL BE
LIMITED BY CLD COVER.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...AVIATION CHALLENGE THRU TONIGHT WL BE
CIGS/VIS AND CHCS FOR LIGHT PRECIP. CRNT SFC ANALYSIS SHOWS LOW
PRES ACRS NEK ATTM...WITH SFC COLD FRNT APPROACHING BTV. EXPECT
WIND SHIFT TO THE NW BTWN 18Z-19Z AT BTV AND 19Z-20Z AT RUT/MPV.
IN ADDITION...CIGS WL DROP BEHIND THE FRNT...BASED ON UPSTREAM
OBS/UPSLOPE FLW AND PLENTY OF BL MOISTURE. OBS AT PBG SHOW A LOW CLD
DECK DEVELOPING AROUND 006FT AND FSO SHOWS OVC002. THESE LOW
CLDS WL DEVELOP FOR A PERIOD BTWN 19Z-23Z ACRS OUR TAF
SITES...ALONG WITH SOME -SN AND BR. EXPECT MVFR TO IFR CONDITIONS
FOR SEVERAL HRS THIS AFTN/EVENING BEHIND FROPA. OTHERWISE...SFC
RIDGE LOCATED OVER THE NORTHERN LAKES WL SLOWLY ADVECT IN DRIER
AIR ON NW WINDS OF 10 T0 20 KNOTS THRU 18Z WEDS.
OUTLOOK...18Z WEDNESDAY THROUGH SUNDAY...
MAINLY VFR CONDITIONS WITH POTENTIAL FOR SOME MTN -SW AND
OCCASIONAL MVFR (SLK/MPV) WEDS THRU FRI. MORE WIDESPREAD SNOW
SHOWERS WL BE POSSIBLE SATURDAY INTO SUNDAY WITH PERIODS OF MVFR TO
IFR CONDITIONS POSSIBLE...ESPECIALLY AT MPV/SLK.
&&
.EQUIPMENT...
THE ASOS TEMPERATURE SENSOR AT SAINT JOHNSBURY VERMONT (1V4) HAS BEEN
RUNNING A BIT TOO WARM LATELY. IT GAVE A HIGH TEMPERATURE OF 43
DEGREES ON MONDAY. THE TEMPERATURE AND DEW POINT SENSORS HAVE BEEN
TEMPORARILY TURNED OFF UNTIL THIS PROBLEM IS FIXED. PARTS ARE ON
ORDER TO FIX THIS SENSOR. OUR ELECTRONICS TECHNICIANS WILL VISIT
THE SITE ON WEDNESDAY TO DO MAINTENANCE WORK ON THIS SENSOR.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...AMF
NEAR TERM...WGH
SHORT TERM...AMF
LONG TERM...JN
AVIATION...TABER
EQUIPMENT...
