FXUS61 KCAR 212105
AFDCAR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
405 PM EST MON DEC 21 2009

.SYNOPSIS...
A TROUGH OF LOW PRESSURE EXTENDING NORTHWEST FROM LOW PRESSURE
WELL EAST OF NOVA SCOTIA WILL BACK EASTWARD INTO THE REGION
TONIGHT AND TUESDAY AS AN UPPER LEVEL LOW SLIDES SOUTH OF THE
AREA. THE TROUGH WILL WEAKEN ON WEDNESDAY AS HIGH PRESSURE SLOWLY
BUILDS OVER THE AREA WEDNESDAY NIGHT AND THURSDAY. 
&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
MAIN FOCUS IS BAND OF SNOW ON AND OFF THROUGH TUESDAY MORNING AND
WHERE TO PLACE THE HIGHEST SNOWFALL.

RADAR SHOWING BANDS OF LIGHT TO OCCASIONALLY MODERATE SNOW DIVING
SOUTH ACROSS THE NORTHERN AND EASTERN SECTIONS OF THE CWA. THE
SREF POPS LOOKED TO MATCH THIS CLOSE AND USED THEM AND THEN
ADJUSTED FOR AREAL COVERAGE THROUGH THE NIGHT. THE NAM AND GFS
SUPPORT THIS BANDING AND SNOW BEGINNING TO CONGEAL MORE ACROSS THE
NORTHERN SECTIONS BY TUESDAY MORNING. WINDS SHOW SIGNS OF VEERING
FROM 850-700BMS W/SOME FORCING TAKING SHAPE OVER THE NORTHERN
TIER. THEREFORE...DECISION WAS TO GO CATEGORICAL ACROSS THE FAR
NORTHERN SECTIONS W/PERIODS OF SNOW W/CHC POPS AS ONE TRAVELS
SOUTH AND SOUTHWESTWARD THROUGH 06Z. PRECIP CHCS(SNOW) WERE
INCREASED TO CATEGORICAL(80%) AS FAR SOUTH AS SOUTH AS MLT AND HUL
BY DRIVE TIME TUESDAY MORNING. ATTM...SNOWFALL ACCUMULATIONS WILL
BE AROUND AN INCH THROUGH 12Z TUESDAY.

TEMPERATURES WILL SLIDE BACK A BIT THIS EVENING AND THEN THEY
LOOK TO LEVEL OFF AS WARMER AIR ABOVE 925MBS GETS ADVECTED
WESTWARD FROM NEW BRUNSWICK. PREVIOUS FORECAST TEMPERATURES
HANDLED THIS WELL BUT WERE ADJUSTED UP A DEGREE OR TWO TO PLAY FOR
THE WARMING ALOFT.
&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
AN OCCLUDED FRONT MOVING SOUTHWARD FROM THE MARITIMES WILL REACH
NORTHERN MAINE TUESDAY AND STALL ACROSS CENTRAL MAINE LATER IN THE
DAY. AS AN UPPER LEVEL DISTURBANCE ARRIVES FROM WESTERN NEW
ENGLAND TUESDAY NIGHT, THE FRONT WILL INTENSIFY AND BRING SNOW ALL
OF THE FORECAST AREA TUESDAY NIGHT INTO EARLY WEDNESDAY. MODELS
STILL SHOW VARIATION IN THE TRACK OF THE UPPER LOW...WHICH WILL
DETERMINE WHERE THE INTENSIFICATION OCCURS ON THE INVERTED TROUGH. GFS
AND NAM12 FAVORED A MORE SOUTHERN TRACK THAT WOULD PLACE HEAVIEST
PRECIP OVER A LINE FROM BANGOR NORTHEAST TOWARD GREENVILLE, BUT
GEMS/ECMWF/UKMET FAVOR A MORE NORTHERN TRACK OF THE UPPER LOW AND
INVERTED TROUGH. HOWEVER, 21/12Z NAM12 SHOWED GOOD LIFT TO THE
NORTH OF ITS FORECAST PRECIP FIELDS. FURTHERMORE, UPPER LEVEL JET
ANALYSIS AND WV IMAGERY INDICATE A MORE NORTHERN TRACK IS FAVORED.
THIS IS A RATHER UNUSUAL EVENT AS OCCLUDED FRONTS FROM THE NORTH
TYPICALLY DON'T BRING MUCH SNOWFALL TO THE AREA. THE COMBINATION
OF UPPER LOW AND THE FRONT MAKES HEAVIER SNOWFALL MORE PLAUSIBLE.
USING CIPS ANALOG TOOL FROM ST LOUIS UNIV, AN SIMILAR SYNOPTIC
PATTERN WAS FOUND IN JAN 1998 THAT BROUGHT OVER A FOOT OF SNOW TO
THE AREA. OVERALL, EXPECT THAT THE STRONGEST LIFT WILL END UP OCCURRING IN
A RELATIVELY NARROW BAND...MEANING THAT THE ACTUAL AREAS RECEIVING
OVER 9-10 INCHES WILL BE IN A NARROWER AXIS THAN CURRENTLY
REFLECTED IN FORECAST GRIDS. THE BROAD AREA IS A REFLECTION OF
STORM TRACK UNCERTAINTY. SNOW RATIOS WILL ALSO PLAY A ROLE WITH
HIGHER RATIOS EXPECTED TO THE SOUTHEAST IN LOCATIONS SUCH AS BGR,
GNR AND MILO. 
&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE MODELS ARE IN GOOD AGREEMENT AT THE START OF THE LONG TERM. 
HIGHER PRESS WILL BE BUILT ACROSS THE CWA. A LOW PRES AND ITS
ASSOCIATED FRONTAL SYSTEM WRAPPED AROUND IT. THE HIGH WILL
CONTINUE TO DOMINATE THE WX THROUGH SAT MORNING AS THE LOW AND ITS
FRONT MOVES EAST. EARLY SAT MORNING A SECONDARY LOW WILL BE CNTRD
AT THE TRIPLE POINT OF THE FRONT OVR LONG ISLAND. MY MID DAY SAT
THE LOW WILL MOVE TO CAPE COD BRINGING PCPN INTO THE SRN CWA. BY
SUN MORNING THE LOW WILL BE OVR EASTPORT ITS ASSOCIATED FRONTAL
SYSTEM EAST IN NEW BRUNSWICK. A WEAK RIDGE OF HIGH PRESS WILL
BUILD IN BEHIND THE EXITING LOW...HOWEVER IT WILL BE BRIEF AS A
TROUGH WILL BRING SCT SHOWERS BACK INTO THE AREA ON MON. UNSETTLED
CONDITIONS WILL CONTINUE THROUGH THE END OF THE PERIOD. LOADED
GMOS GRIDS...MADE MINOR ADJUSTMENTS TO POP AND SKY GRIDS TO BETTER
SUPPORT ONE ANOTHER. LOADED NAWAVE 4 FOR SEAS...WITH MINOR
ADJUSTMENTS DOWN FOR SUN INTO MON.
&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
NEAR TERM: IFR/MVFR FOR THE NORTHERN TAF SITES THROUGH TUESDAY
MORNING. DOWNEAST SITES WILL BE MVFR/VFR TONIGHT DROPPING TO MVFR
BY MID TUESDAY MORNING.

SHORT TERM: EXPECT IFR TO VLIFR CONDITIONS IN SNOW UNTIL WEDNESDAY
AFTERNOON. AREAS SUCH AS BGR MAY START VFR OR MVFR EARLY TUESDAY
BUT WILL DETERIORATE TO IFR DURING THE AFTERNOON. VFR CONDITIONS
WILL OVERSPREAD THE AREA LATER WEDNESDAY AND REMAIN FOR THURSDAY.
&&

.MARINE...
NEAR TERM: SCA EXTENDED THROUGH TUESDAY FOR WINDS AND SEAS.

SHORT TERM: SCA CONDITIONS WILL CONTINUE INTO WED MORNING...
HOWEVER WILL RETURN TO SCA BY EARLY WED AFTERNOON. SCA CONDITIONS
WILL CONTINUE INTO EARLY FRI MORNING. WINDS AND SEAS WILL COME
BACK UP SAT AFTERNOON AS THE NEXT MAJOR LOW PRESS SYSTEM
APPROACHES THE AREA. GALE MAY BE REQUIRED SAT AFTERNOON THROUGH
SUN AFTERNOON AS THIS SYSTEM MOVES THROUGH. WNDS AND SEAS WILL
SUBSIDE EARLY MON.  
&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY 
     EVENING FOR MEZ001>006-010-011-015>017-029>032.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST TUESDAY FOR ANZ050>052.

&&

$$
NEAR TERM...HEWITT
SHORT TERM...MWALKER
LONG TERM...NORTON
AVIATION...HEWITT
MARINE...HEWITT/MWALKER