FXUS61 KBTV 160112
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
812 PM EST TUE DEC 15 2009
.SYNOPSIS...
A LOW PRESSURE AREA OVER NORTHERN MAINE WILL MOVE INTO THE
CANADIAN MARITIMES OVERNIGHT. THIS LOW PRESSURE AREA WILL BRING
BITTERLY COLD ARCTIC AIR INTO THE NORTH COUNTRY ON GUSTY NORTHWEST
WINDS LATE TONIGHT THROUGH THE REMAINDER OF THIS WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 812 PM EST TUESDAY...MINOR UPDATE TO THIS EVENINGS FORECAST
TO ADJUST POPS/WX/SKY BASED ON CURRENT TRENDS. LATEST OBSERVATIONS
AND RADAR TRENDS INDICATE CONTINUING SNOW SHOWER ACTIVITY ACROSS
NORTHEASTERN VERMONT WHILE SOME SCATTERED SNOW SHOWERS HAVE
DEVELOPED DOWNWIND FROM LAKE ONTARIO IN THE NORTHERN ADIRONDACKS.
HAVE INCREASED POPS IN THESE AREAS THROUGH MIDNIGHT...THEN
ACTIVITY SHOULD TAPER OFF AS HIGH PRESSURE BEGINS TO FILTER INTO
THE REGION AND LOW LEVEL MOISTURE THINS. ALSO BASED ON CURRENT
SATELLITE TRENDS...HAVE GONE A BIT MORE PESSIMISTIC ON SKY COVER
FROM PREVIOUS FORECAST. CURRENTLY A GOOD DEAL OF CLOUDS
UPSTREAM...BUT SOME BREAKS ARE NOTED. STILL FEEL SKY COVER WILL
DECREASE OVERNIGHT...JUST NOT SOLD ON SKIES BECOMING MOSTLY CLEAR
SO HAVE GONE WITH PARTLY CLOUDY INSTEAD. UPSTREAM OBS DO SUPPORT
PREVIOUS FORECAST OVERNIGHT TEMPS WITH MANY LOCATIONS UPSTREAM
ALREADY FALLING INTO THE LOWER TEENS AND SINGLE DIGITS. EVEN IF
AREAS DONT CLEAR OUT...TEMPS WILL PLUMMET OVERNIGHT AND WITH RECENT
SNOW/RAIN SHOWERS AND WET ROAD SURFACES...BLACK ICE WILL LIKELY
FORM AREA-WIDE OVERNIGHT. HAVE ALREADY HAD A FEW PHONE CALLS
ABOUT SOME ACCIDENTS DUE TO SLICK ROADWAYS. SEE ALBSPSBTV FOR
MORE DETAILS ON THAT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 414 PM EST TUESDAY...TEMPERATURES WILL NOT CLIMB THAT MUCH
ABOVE OVERNIGHT MIN TEMPERATURES ON WEDNESDAY AS THE REGION WILL
BE UNDER COLD AIR ADVECTION THROUGH THE DAY. MODEL GUIDANCE
SHOWING A SECONDARY COLD FRONT/TROUGH COMING THROUGH THE REGION
WEDNESDAY AFTERNOON. BUFKIT FORECAST SOUNDINGS SHOWING STEEP LOW
LEVEL LAPSE RATES TO DEVELOP ACROSS THE REGION WEDNESDAY
AFTERNOON...AS THE SECONDARY COLD FRONT AND UPPER SHORTWAVE COMES
THROUGH THE REGION...SO HAVE GONE WITH A SLIGHT CHANCE OF SNOW
SHOWERS. THE WINDS WILL STAY UP WEDNESDAY NIGHT WITH TEMPERATURES
FALLING INTO THE SINGLE DIGITS ABOVE AND BELOW ZERO. WIND CHILL
VALUES APPROACH -20 IN THE ADIRONDACKS LATE WEDNESDAY NIGHT AND
EARLY THURSDAY...SO LATER SHIFTS MAY HAVE TO CONSIDER A WIND CHILL
ADVISORY THERE. GUSTY NORTHWEST WINDS WILL CONTINUE INTO THURSDAY
WITH HIGHS RANGING FROM THE SINGLE DIGITS ABOVE ZERO TO THE
TEENS. WIND CHILL VALUES WILL AGAIN APPROACH ADVISORY CRITERIA IN
THE ADIRONDACKS LATE THURSDAY NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 PM EST TUESDAY...THE LONG TERM FOCUS FOR DAYS 4 THRU 7 WL
BE POSITION/MOVEMENT AND STRENGTH OF DEEP MID/UPPER LVL CLOSED
CYCLONIC CIRCULATION AND TIMING OF INDIVIDUAL S/W'S ALONG WITH
TIMING/EVOLUTION OF TROF REPLACEMENT BY NEXT WEEK. OVERALL PATTERN
WL FEATURE BLW NORMAL TEMPS INTO THE WEEKEND...WITH THE CHCS FOR
MAINLY MTN -SW. LATEST 12Z GFS SHOWS MID/UPPER LVL CLOSED CYCLONE
OVER EASTERN CANADA RETROGRADING WEST TWD NORTHERN MAINE...WHILE
FAVORABLE 850 TO 500MB MOISTURE MOVES FROM EAST TO WEST INTO
CENTRAL/NORTHERN VT. IN ADDITION...LLVL WAA OCCURS FROM AIRMASS
COMING OFF THE ATLANTIC...WHICH WOULD HELP TO ENHANCE SOME MTN
-SW. SETUP LOOKS VERY SIMILAR IN MANY WAYS TO THE MARCH 4 2006
EVENT...WHICH OUR FCSTER BANACOS DID AN EXCELLENT WRITE UP ON.
THIS UPCOMING EVENT FEATURES GOOD DEVELOPMENT OF DEEP WRAP AROUND
MOISTURE...CLOSED 7/5H CIRCULATIONS...AND LLVL WAA APPROACHING OUR
FA...FROM THE NORTH. THE MARCH 4TH EVENT DID PRODUCE SOME
ACCUMULATING SNOWS ACRS THE NORTHERN/CENTRAL GREENS AND PARTS OF
THE CPV. WL INCREASE POPS TO CHC ATTM...TO COVER THIS POTENTIAL.
IN ADDITION...LATEST BUFKIT SOUNDINGS SHOW GOOD DEEP LAYER
MOISTURE IN THE FAVORABLE SNOW GROWTH REGION...HELPING IN FLAKE
SIZE AND THE FLUFF FACTOR. WL CONT TO MONITOR TRENDS AND EXACT
PLACEMENT OF SYSTEM...BUT A PROLONG DURATION OF ACCUMULATING MTN
SNOW SHOWERS LOOKS POSSIBLE. OTHERWISE...TEMPS WL SLOWLY REBOUND
SATURDAY INTO SUNDAY...AS MORE CLOUDS AND WARMER 85H TEMPS ADVECT
INTO OUR CWA.
STILL WATCHING NUMEROUS EMBEDDED 5H VORTS IN FLW ALOFT...WITH ONE
ENHANCING DEEP SFC LOW PRES WELL SOUTH AND EAST OF CWA ON SUNDAY
AND ANOTHER FOR EARLY NEXT WEEK. THIS SETUP WITH NUMEROUS VORTS
AND DEEP CLOSED MID/UPPER LVL CIRCULATIONS...WL HAVE TO BE
WATCHED...ESPECIALLY IF FLW BECMS NEGATIVELY TILTED. FOR MONDAY
INTO TUES...TRENDED TWD GMOS TEMPS/PRECIP...WHICH IS CLOSE TO
NORMAL...HIGHS IN THE 20S LOWS IN THE TEENS.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 00Z THURSDAY...AVIATION CHALLENGE THRU TONIGHT WL BE
CIGS/VIS AND CHCS FOR LIGHT PRECIP. CRNT SFC ANALYSIS SHOWS LOW
PRES AND SFC CD FNT E OF FA. MEANWHILE...MID-LVL S/W STL UPSTREAM
AND XPCTD TO ROTATE ACRS FA BTWN 04-08Z ALG WITH MUCH COLDER AIR.
THIS SHLD BE ENUF WITH FVRBL UPSLOPE TO SQUEEZE OUT REMAINING LLVL
MOIST FOR CHC/SCT -SHSN...ESP VT SIDE OF CHMLP VLY AND WRN SLOPES
WITH CHAMPLAIN VLY CONVERGENCE AND RELATIVELY MILD LAKE WATER.
THIS MAY BRG MVFR AND VRY BRF IFR ARD 06Z.
THEREAFTER...DRIER AIR WL WORK ITS WAY INTO FA FOR IMPRVG TO SCT-
BKN 035-050 VFR CONDS. NW WNDS 8-12 WITH LCL G20 KTS TNGT AND
10-20 KTS WED.
OUTLOOK...00Z THURSDAY THROUGH SUNDAY... MAINLY VFR CONDITIONS
WITH POTENTIAL FOR SOME MTN -SW AND OCCASIONAL MVFR (SLK/MPV) WED
NGT 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...WGH
NEAR TERM...LAHIFF
SHORT TERM...WGH
LONG TERM...TABER
AVIATION...TABER/SLW
EQUIPMENT...
