FXUS61 KBOX 012133
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
430 PM EST TUE DEC 1 2009
.SYNOPSIS...
HIGH PRESSURE WILL BRING DRY WEATHER AND NEAR SEASONABLE TEMPERATURES
TO SOUTHERN NEW ENGLAND TONIGHT AND WEDNESDAY. STRONG LOW PRESSURE
WILL BRING HIGH WINDS AND RAIN TO THE REGION LATE WEDNESDAY NIGHT
AND THURSDAY MORNING. AT OR BELOW NORMAL TEMPERATURES WILL FOLLOW
FRIDAY THROUGH THE WEEKEND AND THERE IS EVEN THE CHANCE FOR SOME
SNOW LATE SATURDAY/SATURDAY NIGHT IF LOW PRESSURE COMES CLOSE ENOUGH
TO THE COAST.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AREA OF SNOW SHOWERS REACHED INTO THE BERKSHIRES LATE THIS MORNING
AND EARLY AFTERNOON...BUT HAS SINCE DISSIPATED. STILL NOTE LAKE
EFFECT BANDS WORKING ACROSS NORTHERN NY STATE INTO VT...FAR AWAY
FROM THE REGION.
CLOUDS FROM A WEAKENING SHORT WAVE IN THE FAST UPPER WEST FLOW WILL
MOVE E AND TEND TO DISSIPATE TONIGHT AS HIGH PRESSURE BUILDS OFF THE
MID ATLC COAST...WITH SURFACE RIDGING HELPING TO CLEAR THINGS OUT.
WITH MAINLY LIGHT W-SW WINDS TONIGHT...EXPECT TEMPS TO FALL BACK TO
NEAR SEASONAL LEVELS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
WEDNESDAY...HIGH PRES WILL SHIFT TO THE WESTERN ATLC DURING THE DAY
WHILE LOW PRES TAKES SHAPE OVER THE SOUTHEASTERN U.S. EXPECT A
PLEASANT DAY WITH SW WINDS STARTING TO PICK UP A BIT. TEMPS WILL
REBOUND TO THE UPPER 40S TO LOWER 50S AT MOST LOCATIONS. CLOUD WILL
QUICKLY INCREASE FROM SW-NE DURING THE AFTERNOON AHEAD OF THE NEXT
SYSTEM.
WEDNESDAY NIGHT...RAPIDLY INTENSIFYING LOW PRES WILL WORK ACROSS THE
APPALACHIANS...WITH THE GFS STRONGER THAN THE OTHER SHORT RANGE
MODELS. USED A BLEND OF THE PREVIOUS FORECAST ALONG WITH THE 09Z
SREF...WHICH SEEMED TO BE A GOOD BLEND OF THE 12Z OP MODEL RUNS.
RAIN WILL QUICKLY PUSH INTO THE REGION OVERNIGHT. EXCELLENT MOISTURE
CONVERGENCE WITH THIS SYSTEM WILL BRING A SLUG OF RAIN...POSSIBLY UP
TO AN INCH OF RAIN WITH LOCALLY HIGHER AMOUNTS. GOOD DYNAMICS IN
PLACE AS WELL...SO COULD SEE SCT TSTMS MAINLY NEAR OR AFTER MIDNIGHT.
THERE ARE TWO POTENTIAL PROBLEMS WITH THIS SYSTEM...THE RAPIDLY
INCREASING SOUTHERLY WINDS AND POSSIBLE COASTAL FLOODING. VERY
STRONG LOW LEVEL JET...UPWARD TO 70 KTS AT 925 HPA AND 80 KTS AT 850
HPA...WILL MOVE INTO THE REGION OVERNIGHT. WILL LIKELY SEE AT LEAST
WINDS UP TO ADVISORY LEVEL...WITH THE CHANCE OF REACHING HIGH WIND
WARNING CRITERIA MAINLY ON THE SOUTH COAST. WILL MONITOR THIS ASPECT
CLOSELY...AND COVERED IN THE HAZARDOUS WEATHER OUTLOOK. SEAS ARE
FORECAST TO BUILD QUICKLY ON THE SOUTH COAST...WHICH COULD LEAD TO
POTENTIAL OF COASTAL FLOODING MAINLY ON THE THURSDAY MORNING TIDE.
EXPECT TEMPS TO INCREASE THROUGH THE NIGHT...APPROACHING 60 DEGREES
OR HIGHER BY SUNRISE WITH THE STRONG WARM AIR ADVECTION AHEAD OF THE
APPROACHING COLD FRONT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
THURSDAY...
THE LOW IS EXPECTED TO MOVE THROUGH WESTERN OR CENTRAL NEW YORK
STATE...DEPENDING ON WHICH MODEL ONE BELIEVES. THERE ARE TWO MAIN
THREATS WITH THIS SYSTEM...A PERIOD OF VERY STRONG AND POTENTIALLY
DAMAGING SOUTH TO SOUTHWEST WIND GUSTS AS WELL AS THE POSSIBILITY OF
COASTAL FLOODING ALONG THE SOUTH COAST DURING THE TIME OF HIGH TIDE
THURSDAY MORNING. IN ADDITION...A PERIOD OF HEAVY RAIN IS EXPECTED
WITH EVEN A FEW THUNDERSTORMS ALSO POSSIBLE. MORE SPECIFICALLY...
1) WIND POTENTIAL...
ALL MODELS CONTINUE TO INDICATE AN INTENSIFYING LOW PRESSURE SYSTEM
PASSING WELL WEST OF SOUTHERN NEW ENGLAND. THE GFS IS STRONGEST BUT
ALL OTHER MODELS ARE STRONG ENOUGH. EXPECT SOMEWHERE AROUND A 985 TO
990 MB LOW TO TRACK ACROSS WESTERN OR CENTRAL NEW YORK LATE WED NIGHT
AND THU MORNING. THE 00Z GFS HAD 85 KNOTS AT 850 MB AND THE 06Z RUN
HAS COME DOWN TO 80 KNOTS...OR NEAR 90 MPH. THE 00Z NAM...WHILE NOT
AS DEEP WITH THE LOW PRESSURE AS THE GFS...ACTUALLY HAD A SMALL
BULLSEYE OF 90 KNOTS... OR NEAR 100 MPH... AT 3200 FT OVER
SOUTHERNMOST NEW ENGLAND AROUND DAYBREAK THU. THIS IS PROBABLY TOO
EXAGGERATED. ALL MODELS SHOW 70 KNOTS AT 925 MB. IN ADDITION...
PRESSURE FALLS OF 3 TO 5 MB IN 3 HOURS ARE EXPECTED. TEMPERATURES
ARE FORECAST TO SOAR OVERNIGHT...REACHING 60 DEGREES IN SOUTHEAST MA
AND RI BY DAYBREAK THU. UPON SUNRISE...THEY WILL RISE INTO THE MID
60S AND HELP PROMOTE VERY GOOD MIXING TO THE SURFACE. ALTHOUGH
SURFACE WINDS MAY GUST TO 30-40 MPH ESPECIALLY ALONG THE COAST WED
NIGHT...BUFKIT PROFILES FOR BOTH THE NAM AND GFS SHOW THE STRONGEST
WINDS OCCURRING WITH MIXING ALONG AND AFTER THE FRONTAL PASSAGE.
THE UPSHOT...EXPECT SOLID WIND ADVISORY CRITERIA...WHICH IS SUSTAINED
WINDS 31-39 MPH OR GUSTS 46-57 MPH...OVER A LARGE PORTION OF THE AREA
BEGINNING ON THE SOUTH COAST WED NIGHT BEFORE DAYBREAK AND
OVERSPREADING MOST OF THE REGION THU ESPECIALLY BETWEEN 10 AM AND
3 PM ON SOUTHWEST WINDS BEHIND THE FRONT. WIND ADVISORY LEVEL WINDS
CAN CAUSE SCATTERED POWER OUTAGES AND FALLING TREE LIMBS. THERE IS A
CHANCE OF REACHING HIGH WIND WARNING CRITERIA...WITH SUSTAINED WINDS
40 MPH OR GREATER AND A FEW GUSTS TO 58 MPH OR HIGHER. AT THESE
LEVELS...THERE IS THE POTENTIAL FOR MORE WIDESPREAD POWER OUTAGES AND
DOWNED TREES. THE MOST LIKELY AREAS FOR THIS TO OCCUR WOULD BE FROM
PLYMOUTH TO FALL RIVER...AS WELL AS ON THE CAPE AND ISLANDS. A HIGH
WIND WATCH MAY BE NEEDED FOR PARTS OF THE AREA IN LATER FORECAST
PACKAGES.
2) MODERATE COASTAL FLOOD POTENTIAL ON THE SOUTH COAST THURSDAY
MORNING...
THE HIGHEST ASTRONOMICAL TIDES OF DECEMBER WILL BE OCCURRING ON
THURSDAY MORNING TO BEGIN WITH. IN ADDITION...THE STRONG WINDS
MENTIONED ABOVE MAY COINCIDE WITH THE ASTRONOMICAL HIGH TIDE...WHICH
ROUGHLY OCCURS AROUND 8 OR 9 AM IN THE MORNING ON THE SOUTH COAST.
THE EXACT TIMING WILL HAVE A HUGE IMPACT ON COASTAL FLOOD POTENTIAL.
THERE IS A CHANCE THAT THE STRONGEST WINDS WILL OCCUR JUST AFTER THE
HIGH TIDE. HOWEVER...THE POTENTIAL EXISTS FOR A 2 FOOT OR HIGHER
STORM SURGE AT THE TIME OF ASTRONOMICAL HIGH TIDE ALONG THE SOUTH
COAST. THIS WILL BRING THE POTENTIAL FOR MODERATE COASTAL FLOODING
ESPECIALLY ACROSS BUZZARDS AND NARRAGANSETT BAYS. MODERATE COASTAL
FLOODING MEANS THAT THERE IS THE POTENTIAL FOR STRUCTURAL DAMAGE TO
VULNERABLE AREAS. A COASTAL FLOOD WATCH MAY BE NEEDED IN SUBSEQUENT
FORECAST PACKAGES.
3) HEAVY RAIN AND A FEW THUNDERSTORMS... STRONG FORCING AND DYNAMICS
WILL YIELD A PERIOD OF HEAVY RAIN SHOWERS...ESPECIALLY WITH GOOD
MOISTURE RETURN AND DEW POINTS REACHING WELL INTO THE 50S TO NEAR 60.
FORTUNATELY...THE SYSTEM IS A FAST MOVER SO WE ARE ONLY EXPECTING A
QUICK 1.00 TO 1.50 INCHES WITH PERHAPS SOME LOCALLY HIGHER AMOUNTS.
NO SIGNIFICANT SMALL STREAM OR RIVER FLOODING IS EXPECTED...BUT WE
WILL LIKELY SEE TYPICAL URBAN AND POOR DRAINAGE STREET FLOODING. IN
ADDITION...A STRONG LOW LEVEL JET AND MARGINAL INSTABILITY MAY YIELD
SCATTERED THUNDERSTORMS FOR A FEW HOURS LATE WED NIGHT OR EARLY
THURSDAY MORNING...NOT THE USUAL TIME FOR THUNDER.
ALL INDICATIONS ARE THAT SKIES WILL BREAK OUT INTO SUNSHINE THURSDAY
AFTERNOON.
FRIDAY THROUGH MONDAY...
ALL THE MODELS ARE IN GENERAL AGREEMENT IN UPPER LEVEL TROUGH
ESTABLISHING ITSELF OVER THE OHIO VALLEY AND EVENTUALLY THE
NORTHEAST. THIS WILL BE A PATTERN SHIFT COMPARED TO THE RELATIVELY
MILD WEATHER THAT WE HAVE SEEN FOR THE PAST MONTH. EXPECT
TEMPERATURES TO AVERAGE AT OR BELOW NORMAL THROUGH THE PERIOD.
THE MAIN WEATHER ISSUE WILL BE THE POTENTIAL FOR A SIGNIFICANT
COASTAL STORM LATE SATURDAY INTO SUNDAY. THE 00Z GFS HAD A DEEPENING
LOW PRESSURE SYSTEM OUT TO SEA BUT CLOSE ENOUGH TO GIVE THE CAPE AND
EASTERN SECTIONS OF SOUTHERN NEW ENGLAND SOME RAIN...CHANGING TO
SNOW. THE ECMWF MODEL WAS MUCH FARTHER TO THE SOUTHEAST...ALLOWING
SOUTHERN NEW ENGLAND TO ESCAPE ANY PRECIPITATION. AS A RESULT...HAVE
CONTINUED THE CURRENT FORECAST WITH CHANCE POPS.
IT SHOULD BE NOTED THAT THE 06Z GFS HAS NOW CREATED A MAJOR NOREASTER
OVER THE BENCHMARK WHICH WOULD MEAN A LOT OF SNOW FOR PORTIONS OF
SOUTHERN NEW ENGLAND. THIS IS A LONG WAY OUT IN THE FUTURE AND MODEL
SOLUTIONS ARE BOUND TO CHANGE QUITE A BIT. THE EVOLUTION OF THIS
SYSTEM IS HIGHLY DEPENDENT ON THE PHASING OF TWO AREAS OF
VORTICITY...ONE THAT IS FORECAST TO DIVE INTO THE TEXAS PANHANDLE
AND THE OTHER EMANATING FROM THE CENTRAL GULF OF MEXICO.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
TONIGHT AND WEDNESDAY...VFR. CIGS WILL START TO LOWER TO AROUND 5KFT
DURING WEDNESDAY AFTERNOON ACROSS N CT/RI...QUICKLY PUSHING ACROSS
THE REMAINDER OF THE REGION.
WEDNESDAY NIGHT...GENERAL MVFR-IFR CIGS/VSBYS WITH AREAS LIFR IN
LOCALLY HEAVY RAINFALL AND AREAS OF FOG. SCT TSTMS POSSIBLE NEAR OR
AFTER MIDNIGHT. S-SW WIND GUSTS UP TO 45 KNOTS POSSIBLE.
OUTLOOK /THURSDAY THROUGH SATURDAY/...
THURSDAY...MVFR-IFR CONDITIONS THURSDAY MORNING IN HEAVY
RAIN...STRONG SOUTH TO SOUTHWEST WIND GUSTS TO 45 KT...ALONG WITH
SCATTERED THUNDERSTORMS. CONDITIONS IMPROVING FROM W-E DURING THE
AFTERNOON.
THURSDAY NIGHT AND FRIDAY...MAINLY VFR CONDITIONS EXPECTED.
SATURDAY...LOW CONFIDENCE BUT MVFR-IFR CONDITIONS ARE POSSIBLE IN A
PERIOD OF SNOW.
&&
.MARINE...
TONIGHT...SMALL CRAFT CONTINUES INTO THE EVENING MAINLY FOR LEFTOVER
5 FOOT SEAS.
WEDNESDAY...HIGH PRES PUSHES E OF THE WATERS...WITH LIGHT W-SW WINDS
AND SEAS BELOW 5 FEET.
WEDNESDAY NIGHT...HAVE ISSUED A GALE WATCH FOR RAPIDLY INCREASING
S-SW WINDS...GUSTING UP TO 40-45 KTS LATE. SEAS QUICKLY BUILD...UP
TO 9-13 FEET BY SUNRISE THURSDAY.
OUTLOOK /THURSDAY THROUGH SATURDAY/...
THURSDAY...A PERIOD OF SOUTHERLY GALE FORCE WINDS ARE EXPECTED ALONG
WITH RAPIDLY BUILDING SEAS TO BETWEEN 10 AND 15 FEET OVER THE
SOUTHERN OUTER-WATERS. THERE IS A LOW PROBABILITY OF STORM FORCE
WIND GUSTS FOR AN HOUR OR TWO.
FRIDAY...WINDS SHOULD DIMINISH BELOW SCA CRITERIA BUT SEAS WILL
REMAIN ABOVE SCA THRESHOLDS ACROSS THE SOUTHERN OUTER-WATERS.
SATURDAY...THE POTENTIAL EXISTS FOR GALE FORCE NORTHEAST WINDS
AS LOW PRESSURE DEVELOPS OFF THE COAST. CONFIDENCE IS LOW TO MEDIUM
AT THIS TIME AS TO HOW FAR OFFSHORE THE STORM MIGHT BE.
&&
.CLIMATE...
BOSTON/S LOGAN AIRPORT HAS NOT FALLEN TO THE FREEZING MARK SO FAR
THIS SEASON. THE RECORD LATEST IN THE SEASON THAT BOSTON HAS
RECORDED ITS FIRST 32F WAS DEC 2ND 1975. AVERAGE FIRST DATE OF 32 IN
BOSTON IS AROUND NOVEMBER 4TH. OVERNIGHT LOWS TONIGHT AND WEDNESDAY
NIGHT FORECASTED TO REMAIN ABOVE FREEZING.
NOVEMBER 2009 WAS TOP 10 WARMEST AT OUR 4 CLIMATE SITES. BELOW ARE
PRELIMINARY NOVEMBER TEMPERATURE AVERAGES AND DEPARTURES FOR THE
MONTH.
BOS 48.8...PLUS 3.9...RANKED NUMBER 6.
BDL 46.4...PLUS 4.6...RANKED NUMBER 6.
PVD 48.9...PLUS 5.1...RANKED NUMBER 3.
ORH 44.5...PLUS 4.9...RANKED NUMBER 5.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
AFTERNOON FOR ANZ231>235-237-250-254>256.
GALE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
AFTERNOON FOR ANZ230-236-251.
SMALL CRAFT ADVISORY UNTIL 9 PM EST THIS EVENING FOR ANZ254-
255.
SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR ANZ256.
&&
$$
SYNOPSIS...GAF
NEAR TERM...EVT
SHORT TERM...EVT
LONG TERM...GAF
AVIATION...EVT/GAF
MARINE...EVT/GAF
CLIMATE...STAFF
