FXUS61 KBTV 220235
AFDBTV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
935 PM EST MON DEC 21 2009
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION TONIGHT
THROUGH WEDNESDAY...ACCOMPANIED BY SOME LIGHT SNOW SHOWERS. NO
SIGNIFICANT ACCUMULATIONS ARE EXPECTED. A MORE SIGNIFICANT STORM
IS EXPECTED FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 928 PM EST MONDAY...A QUICK UPDATE TO FRESHEN THE FORECAST
TO CURRENT TRENDS. CLOUDS HAVE MOVED IN FURTHER WEST IN VT..INTO
THE CHAMPLAIN VALLEY WITH BROKEN TO OVERCAST DECK OVER BURLINGTON.
HAVE BUMPED UP SKY COVER NORTHERN HALF OF VT...WHILE STILL CLEAR
TO PARTLY CLOUDY IN THE ADIRONDACKS. ALSO UPDATED TEMPS WITH NEWER
LAV GUIDANCE WHICH IS A DEGREE OR TWO WARMER THAN PREVIOUS
FORECAST...LIKELY BASED ON THE ADDITIONAL CLOUD COVER. LEFT POPS
ALONE...WITH CHC IN NE KINGDOM AFTER MIDNIGHT AND SLIGHT CHC
ELSEWHERE. LYNDONVILLE AIRPORT OB HAD LIGHT SNOW IN 02Z OB...AND
EXPECT OFF/ON SNOW IN NE VT WITH NO ACCUMULATIONS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 330 PM EST MONDAY...SHORTWAVE WILL REMAIN OVER THE FORECAST
AREA TUESDAY. MOISTURE WRAPPING AROUND FROM DEPARTING LOW
PRESSURE SYSTEM WILL ALSO CONTINUE TO PLAY A ROLE INFLUENCING THE
WEATHER ACROSS THE NORTH COUNTRY. THAT MOISTURE ALONG WITH
SHORTWAVE DROPPING ACROSS THE AREA WILL PROVIDE SOME SNOW SHOWERS
TO THE NORTH COUNTRY...ESPECIALLY IN NORTHWEST UPSLOPE AREAS. MID
LEVEL MOISTURE IS FAVORABLE WITH THIS FEATURE...SO ALTHOUGH WE
HAVE SURFACE HIGH PRESSURE BUILDING...THE UPPER TROF ABUNDANT
MOISTURE AND SOME LIFT WILL COMBINE TO BRING SOME SNOW SHOWERS TO
THE REGION. WITH LOW LEVELS AS DRY AS THEY ARE...WILL DETER ANY
SIGNIFICANT SNOWFALL. UP TO A FEW INCHES OF SNOW ARE EXPECTED IN
THE NORTHEAST KINGDOM WITH ONE TO TWO INCHES ELSEWHERE. SNOW
SHOWERS WILL CONTINUE TUESDAY NIGHT AS IT SLOWLY SLIDES
EAST...AND SHOULD END WEDNESDAY NIGHT AS SHORTWAVE FINALLY MOVES
OFF THE COAST OF NEW ENGLAND AND BEGINS TO MOVE AWAY FROM THE
AREA. TEMPERATURES WILL CONTINUE TO RUN A BIT BELOW NORMAL
THROUGH THE SHORT TERM WITH PERSISTENT COLD NORTHWEST FLOW.
SURFACE HIGH PRESSURE WILL BEGIN TO RIDGE INTO THE REGION
WEDNESDAY NIGHT BEHIND DEPARTING SHORTWAVE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM EST MONDAY...SURFACE HIGH PRESSURE BUILDS INTO THE
REGION FROM THE NORTH ON THURSDAY AS UPPER LEVEL RIDGE AMPLIFIES
OVER THE EASTERN GREAT LAKES. THIS RIDGE WILL PROVIDE MAINLY DRY
CONDITIONS TO THE NORTH COUNTRY THURSDAY THROUGH MUCH OF
CHRISTMAS DAY. EXTENDED MODELS REMAIN IN GOOD AGREEMENT REGARDING
THE LOW PRESSURE SYSTEM WHICH WILL AFFECT THE AREA CHRISTMAS
NIGHT INTO THE WEEKEND. THIS RESULTS IN HIGH CONFIDENCE THAT THE
AREA WILL SEE PRECIPITATION...BUT PRECIPITATION TYPE IS STILL IN
QUESTION. PRIMARY LOW EXPECTED TO LIFT OUT OF THE SOUTHERN PLAINS
ON THURSDAY INTO THE CENTRAL GREAT LAKES REGION FRIDAY...WITH A
SECONDARY LOW DEVELOPMENT NEAR THE MID ATLANTIC COAST FRIDAY
NIGHT INTO SATURDAY. MEANWHILE...HIGH PRESSURE REMAINS IN PLACE
OVER EASTERN CANADA FRIDAY NIGHT...RETREATING FURTHER TO THE
NORTHEAST ON SATURDAY. WITH COLD AIR IN PLACE AT THE ONSET OF THE
EVENT...PRECIPITATION WILL LIKELY BEGIN AS SNOW...BUT AS WARMER
AIR ALOFT BECOMES ENTRAINED INTO THE SYSTEM...EXPECT A CHANGEOVER
FROM SNOW TO RAIN IN MOST AREAS LATER FRIDAY NIGHT INTO SATURDAY.
SOME SLEET OR FREEZING RAIN IS POSSIBLE DURING THE TRANSITION AS
LOW LEVEL COLD AIR WILL BE DIFFICULT TO DISPLACE IN SOME
AREAS...PARTICULARLY NORTHEAST VERMONT. THE POSSIBILITY FOR SLEET
AND/OR FREEZING RAIN FRIDAY NIGHT WILL HAVE TO BE MONITORED.
MILDER AIR IN LOW LEVELS ARRIVES SATURDAY...RESULTING IN RAIN OR
MIXED RAIN/SNOW. ANY MIX WILL CHANGE TO SNOW SHOWERS SATURDAY
NIGHT AS COLDER AIR RETURNS. THE REGION WILL REMAIN UNDER THE
INFLUENCE OF AN UPPER TROUGH SUNDAY INTO MONDAY. AIRMASS
CONTINUES TO COOL THROUGH THE PERIOD WITH A CHANCE OF SNOW
SHOWERS.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
THROUGH 00Z WEDNESDAY...UPDATED TO KMSS TO REMOVE AMENDMENT
RESTRICTION WITH ASOS RETURN TO SERVICE.
PREV DISCUSSION...MAINLY VFR CONDITIONS EXPECTED...WITH MID AND
HIGH CLOUDS OVER THE REGION THROUGH TONIGHT. ANY LINGERING
SCATTERED SNOW SHOWERS AND MVFR CONDITIONS OVER NORTHEAST VERMONT
WILL DISSIPATE OVERNIGHT...AND ARE NOT EXPECTED TO IMPACT ANY TAF
SITES. TROUGH NORTH OF THE GREAT LAKES WILL MOVE SOUTHEAST INTO
FORECAST AREA TUESDAY. THIS WILL RESULT IN CEILINGS LOWERING TO
AROUND 4000 FEET....EXCEPT AT KSLK AND KMPV WHERE MVFR CEILINGS
EXPECTED. STARTING TO SEE WINDS DROP OFF AS WEAK INVERSION STARTS
TO SET UP.
AFTER 18Z TUESDAY...EXPECT LIGHT SNOW IN THE VERMONT AND NEW YORK
MOUNTAINS AS THE UPPER LOW APPROACHES...ESPECIALLY IN FAVORED
NORTHWEST FACING UPSLOPE AREAS. DID NOT INCLUDE IN TAFS AS CIG/VIS
IMPACT MINIMAL AND NOT WARRANTED THAT FAR OUT IN TIME.
OUTLOOK...00Z WEDNESDAY THROUGH SATURDAY... UPPER LEVEL TROUGH
MOVES SLOWLY ACROSS REGION THROUGH WEDNESDAY WILL PRODUCE SCATTERED SNOW
SHOWERS AND POSSIBLE MVFR CONDITIONS...ESPECIALLY OVER THE HIGHER
TERRAIN TAF SITES. VFR CONDITIONS EXPECTED THURSDAY THROUGH MUCH
OF FRIDAY AS REGION WILL BE UNDER A RIDGE OF HIGH PRESSURE. LOW
PRESSURE WILL BRING LOWERING CEILINGS AND VISIBILITIES IN
PRECIPITATION FRIDAY NIGHT INTO SATURDAY. EXPECT CONDITIONS TO
LOWER TO MVFR AND POSSIBLY IFR IN MIXED PRECIPITATION.
&&
.EQUIPMENT...
KMSS ASOS...COMMUNICATIONS CABLE HAS APPARENTLY BEEN REPAIRED AS
OBSERVATIONS ARE NOW AVAILABLE.
KSLK ASOS...THE TEMPERATURE SENSOR AT KSLK IS MALFUNCTIONING AND
SHOULD BE FIXED TOMORROW. UNTIL THEN THE TEMPERATURE SENSOR HAS
BEEN TURNED OFF.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...NEILES
NEAR TERM...HANSON
SHORT TERM...NEILES
LONG TERM...RJS
AVIATION...HANSON
EQUIPMENT...BTV
