FXUS61 KBOX 150922
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
421 AM EST TUE DEC 15 2009
.SYNOPSIS...
LOW PRESSURE TRACKING ACROSS NORTHERN NEW ENGLAND WILL PUSH A STRONG
COLD FRONT THROUGH THE REGION LATE THIS AFTERNOON AND EVENING.
BLUSTERY AND UNSEASONABLY COLD WEATHER WILL FOLLOW WEDNESDAY THROUGH
THE WEEKEND. A COASTAL STORM MAY THREATEN SOUTHERN NEW ENGLAND
SOMETIME LATE IN THE WEEKEND BUT ITS TRACK AND ANY EFFECTS ARE
HIGHLY UNCERTAIN.
&&
.NEAR TERM /THROUGH TODAY/...
GENERALLY A DRY AND MILD MID DECEMBER DAY IS ON TAP FOR SOUTHERN NEW
ENGLAND. WEAK BOUNDARY LAYER MIXING WILL LIKELY TRAP LOW LEVEL
MOISTURE BENEATH THE INVERSION. THIS SHOULD RESULT IN RATHER CLOUDY
SKIES ACROSS THE REGION FOR MUCH OF THE DAY. DESPITE THE CLOUD
COVER...MILD MID LEVEL TEMPERATURES AND A MILD START SHOULD YIELD
HIGHS WELL UP INTO THE 40S TO POSSIBLY SOME LOWER 50S ACROSS RHODE
ISLAND/SOUTHEAST MA.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
TONIGHT...
A STRONG COLD FRONT WILL MOVE ACROSS THE REGION DURING BY EARLY THIS
EVENING. WHILE THE FRONT SHOULD MOVE THROUGH DRY WITH LITTLE
MOISTURE AVAILABLE...IT WILL USHER IN MUCH COLDER AIR INTO SOUTHERN
NEW ENGLAND. LOW TEMPERATURES BY 12Z WEDNESDAY WILL GENERALLY BE
IN THE 20S UNDER MOSTLY CLEAR SKIES.
WEDNESDAY...
DESPITE PARTLY TO MOSTLY SUNNY SKIES IT WILL BE A WINDY AND VERY
COLD DAY. STRONG COLD ADVECTION SHOULD HOLD HIGH TEMPERATURES IN
THE MID TO UPPER 20S ACROSS THE INTERIOR HIGH TERRAIN...TO THE LOWER
30S IN THE LOWER ELEVATIONS. LOWED MOS GUIDANCE A FEW DEGREES BASED
ON 2 METER TEMPERATURES AND STRONG COLD AIR ADVECTION. IN
ADDITION...A WELL MIXED ATMOSPHERE WILL SUPPORT NORTHWEST WIND GUSTS
OF 20 TO 30 MPH WITH GUSTS TO 40 MPH. MOST LOCATIONS WILL PROBABLY
FALL JUST SHORT OF WIND ADVISORY CRITERIA DURING THE DAY
WEDNESDAY...BUT ITS POSSIBLE A FEW LOCATIONS TOUCH CRITERIA.
REGARDLESS...WIND CHILL VALUES SHOULD BE IN THE TEENS FOR MOST OF
THE DAY. IT CERTAINLY WILL FEEL VERY COLD AFTER THE MILD WEATHER OF
TODAY.
AS FOR PRECIPITATION CHANCES GENERALLY EXPECT A DRY DAY.
HOWEVER...WE MAY SEE A FEW SNOW FLURRIES OR PERHAPS A PASSING SNOW
SHOWER ACROSS SOUTHWEST NH AS WELL AS THE EAST SLOPES OF THE
BERKSHIRES IN MASSACHUSETTS DURING THE AFTERNOON. WILL INCLUDE A 20
POP IN THIS REGION BY LATE AFTERNOON/EARLY EVENING.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
VERY COLD AIRMASS WILL AFFECT SOUTHERN NEW ENGLAND THROUGH MUCH OF
THE PERIOD...WITH AVERAGING 10 TO 20 DEGREES BELOW NORMAL WEDNESDAY
NIGHT THROUGH AT LEAST FRIDAY. WHILE WE WILL HAVE FAIR WEATHER WITH
PLENTY OF SUNSHINE DURING THIS TIME...WIND CHILL VALUES WILL BE VERY
COLD...WITH THOSE READINGS AT OR BELOW ZERO DURING AT NIGHT AND IN
THE SINGLE NUMBERS/TEENS DURING THE DAY. WIND TRAJECTORIES FAVOR ANY
OCEAN AFFECT SNOW SHOWERS TO REMAIN OFFSHORE...BUT CAN/T RULE OUT
SOME BRIEF/LIGHT ACTIVITY ON THE OUTER CAPE.
THE FORECAST THEN BECOMES MORE COMPLEX FOR THE WEEKEND. FROM TIME TO
TIME...VARIOUS MODEL GUIDANCE MEMBERS HAVE BEEN ADVERTISING STRONG
COASTAL LOW PRESSURE DEVELOPMENT ON THE EAST COAST AROUND THE
SUNDAY/MONDAY TIME FRAME. HOWEVER...THE WILD SWINGS IN THE SOLUTIONS
CONTINUE TO BE PRESENT AS THE GUIDANCE IS HAVING A TOUGH TIME
PROJECTING HOW THE POLAR VORTEX AND A SOUTHERN STREAM SHORT WAVE
INTERACT. FOR THE MOST PART...THE MODELS SOLUTIONS HAVE SHOWN AN OUT-
TO-SEA SCENARIO WITH LITTLE EFFECT ON SOUTHERN NEW ENGLAND. AS OF THE
LATEST 00Z MODEL RUN...THESE MEMBERS INCLUDE THE GFS...PARALLEL
GFS...GFS ENSEMBLE...UKMET. HOWEVER...THE ECMWF HAS SHIFTED WESTWARD
TOWARD THE COAST AND THE GGEM IS ALSO CLOSE ENOUGH TO GRAZE THE AREA.
IN A NUTSHELL...THE SUNDAY/MONDAY FORECAST IS A LOW CONFIDENCE ONE.
CHANCES ARE THAT ANY STORM THAT DEVELOPS WILL GRAZE OR MISS THE
REGION. HOWEVER...IF THE NORTHERN STREAM POLAR VORTEX MOVES INTO A
MORE FAVORABLE POSITION AND PHASES WITH THE SOUTHERN STREAM WAVE JUST
RIGHT...SNE COULD BE IN FOR A HECK OF A SNOWSTORM. IT WOULD ONLY TAKE
A SMALL SHIFT WESTWARD IN THE NORMALLY-RELIABLE ECMWF TO BE
SIGNIFICANT SNOWSTORM FOR MUCH OF SOUTHERN NEW ENGLAND AS IT IS.
OVERALL...EXPECT POOR RUN TO RUN CONSISTENCY IN THE MODELS OVER THE
NEXT FEW DAYS AS THE FLOW OVER NORTH AMERICA REMAINS TOUGH TO GET A
HANDLE ON.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
TODAY...HIGH CONFIDENCE THAT MVFR CEILINGS WILL CONTINUE FOR MUCH OF
THE MORNING WITH EVEN A PERIOD OF IFR CONDITIONS AT SOME OF THE
TERMINALS. CEILINGS MAY IMPROVE TO MARGINAL VFR LEVELS FROM
SOUTHWEST TO NORTHEAST DURING THE AFTERNOON.
TONIGHT...VFR CONDITIONS EXPECTED UNDER STRONG COLD ADVECTION.
NORTHWEST WIND GUSTS OF 25 KNOTS ARE ALSO EXPECTED TO DEVELOP AT
MANY OF THE TERMINALS...WITH EVEN A BIT STRONGER AT THE ACK TERMINAL.
WEDNESDAY...MAINLY VFR CONDITIONS EXPECTED DESPITE A SCATTERED TO
BROKEN DECK OF STRATO-CUMULUS CLOUDS DEVELOPING ACROSS THE INTERIOR.
MARGINAL MVFR CONDITIONS MAY WORK INTO NORTHWEST MA/SOUTHWEST NH
DURING THE AFTERNOON. OTHERWISE...NORTHWEST WIND GUSTS OF 35 KNOTS
ARE LIKELY TO DEVELOP ACROSS MOST OF THE TERMINALS WITH A LOW
PROBABILITY OF GUSTS UP TO 40 KNOTS.
OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...
WEDNESDAY NIGHT THROUGH FRIDAY...VFR. NW WINDS GUSTING TO 30 TO 35
KT WITH SOME MECHANICAL TURBULENCE.
SATURDAY...VFR WITH LIGHTER WINDS.
&&
.MARINE...
TODAY...
LEFT OVER SCA FOR ROUGH SEAS ACROSS THE SOUTHERN OUTER-WATERS WILL
DIMINISH EARLY THIS MORNING. OTHERWISE...WINDS AND SEAS SHOULD
GENERALLY REMAIN BELOW SCA THRESHOLDS FOR MOST OF THE DAY.
TONIGHT AND WEDNESDAY...
A STRONG COLD FRONT WILL MOVE THROUGH THE REGION BY EARLY THIS
EVENING. STRONG COLD ADVECTION OVER THE RELATIVELY WARM OCEAN WILL
RESULT IN HIGH CONFIDENCE IN GALE FORCE WEST TO NORTHWEST WIND GUSTS
DEVELOPING ACROSS ALL WATERS LATE TONIGHT THROUGH WEDNESDAY. GALE
WATCHES HAVE BEEN CONVERTED TO GALE WARNINGS FOR NORTHWEST WIND
GUSTS OF 35 TO 40 KNOTS ACROSS ALL WATERS OVER THIS TIME.
OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...
WED NIGHT THRU THURS NIGHT...HIGH PROB OF NW GALES...STRONGEST
EASTERN WATERS.
FRI...SCA WINDS EXPECTED WITH LOW PROB OF GALES IN THE MORNING.
SAT...SCA WINDS AND SEAS POSSIBLE...ESPECIALLY OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WARNING FROM 10 PM THIS EVENING TO 7 PM EST WEDNESDAY FOR
ANZ230>237-250-251-254>256.
&&
$$
SYNOPSIS...FRANK
NEAR TERM...FRANK
SHORT TERM...FRANK
LONG TERM...EKSTER
AVIATION...EKSTER/FRANK
MARINE...EKSTER/FRANK
