FXUS61 KBOX 300359
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1059 PM EST SUN NOV 29 2009
.SYNOPSIS...
LOW PRESSURE OVER WESTERN NEW YORK STATE WILL ADVANCE EASTWARD OVERNIGHT.
A STRONG COLD FRONT WILL SWEEP ACROSS SOUTHERN NEW ENGLAND MONDAY
AFTERNOON BRINGING A PERIOD OF RAIN SHOWERS...FOLLOWED BY DRY BRISK
WEATHER ON TUESDAY. THERE IS THE POTENTIAL FOR A STRONG STORM SYSTEM
BRINGING WIND DRIVEN RAIN LATE WEDNESDAY NIGHT INTO THURSDAY...
FOLLOWED BY SEASONABLY CHILLY AND MAINLY DRY WEATHER FRIDAY THROUGH
NEXT SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
UPDATE... NOT MUCH CHANGE TO FORECAST. JUST A FEW TEMPERATURE
ADJUSTMENTS...COOLER IN SOUTHERN NEW HAMPSHIRE BY A FEW DEGREES AND
WARMER BY A FEW DEGREES IN THE HARTFORD AREA BASED ON CURRENT
OBSERVATIONS. CLOUD COVER SHOULD HOLD TEMPERATURES NEARLY STEADY
OVERNIGHT. POPS STILL LOOK GOOD.
PREVIOUS DISCUSSION...
NEXT FAST MOVING SHORTWAVE MOVES EAST FROM THE GT LAKES
TONIGHT AND TRACKS ACROSS NORTHERN NEW ENGLAND MONDAY. ASSOCD
"STRENGTHENING" COLD FRONT MOVES WEST TO EAST ACROSS SNE MON
AFTERNOON AND EARLY EVENING.
BULK OF SHOWERS WILL OVERSPREAD SNE DURING MONDAY...MAY BEGIN NW
FRINGE OF THE FA AFTER 09Z MONDAY. 15Z SREF POPS USED AND IN AGREEMENT
WITH MANY 12Z OP MODELS ON VIRTUALLY NIL PRIOR TO 10Z IN OUR CWA.
CONFIDENCE HIGH ON THE FCST DETAILS TONIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
RI AND SE MASS...MOST OF THE SHOWERS MAY HOLD OFF TIL MON AFTN. DUE
TO THE INCREASING FGEN...LIGHT TO MDT SHOWERS SHOULD BECOME MORE
WDSPRD AS THE FRONT CROSSES SNE...ESP SE 2/3RDS OF THE AREA. WE DO
SEE 12Z/29 RGEM AND GGEM AND 18Z NAM AS MORE CONSERVATIVE ON QPF BUT
ATTM .. SIDED WITH THE WETTER VERSIONS OF THE 12Z GFS/NAM UKMET AND
ECMWF.
THEREFORE...15Z SREF POPS RAISED 10 PCT DURING THE MIDDAY HOURS MONDAY
ALONG AND S OF THE MASS PIKE. MILD PRIOR TO THE SHOWERS INTO THE
FORENOON AND MIDDAY HOURS BDL ORH BOS SEWD WITH EVEN A LITTLE MORNING SUN?
THEN COOLING DURING THE AFTN IN SHOWERS.
CONFIDENCE ON THE DETERMINISTIC DETAILS MONDAY IS AVG.
MON NIGHT...SHOWERS ENDING SE NEW ENGLAND EVENING PER 15Z/29 SREF
POPS AND MULTI 12Z/29 OP MODEL AGREEMENT AS STRENGTHENING CFP MOVES
OFFSHORE AND GUSTY NW WINDS DEVELOP. MODELS WITH A NOTABLE INTENSIFYING
500 MB VORT-HFC /200M 12 HR/ CROSSING THE NJ COAST AT NIGHT SUGGESTING
AS PER PREV MODEL CYCLES THERE MAY BE SOME LAGGING OF THE SHOWER
DEPARTURE SE MASS AND HAVE RAISED OUR GUIDANCE A BIT IN THAT AREA.
THIS IDEA IS NOT IN AGREEMENT WITH THE 12Z EC...THEREFORE UNCERTAINTY
EXISTS REGARDING TIMING THE END OF THE SEVERAL HOUR WIDE SHOWER BAND.
NO SNOW FCST AT THE TAIL END DUE TO MILD BL TEMPS.
A DECENT SHOT OF CAA LATE MON NIGHT AND WHILE WE ARE NOT YET FCSTG
32F TUE MORNING DEC 1 IN BOS...IT MIGHT NUDGE FREEZING AT LOGAN PER
SEVERAL MODELS T1 TEMPS INCLUDING 18Z NAM.
AS OF THIS FCST...THE 12Z/29 NAM/GFS MOS WAS BLENDED FOR TT/TD/WIND
21Z TDY THRU 12Z TUE. SKY WAS AN APPROX 12Z/29 RGEM GFS/NAM 30/40/30
BLEND. GUSTS DRIVEN SOLELY FROM THE 12Z/29 NAM MXG HTS AND GUSTS
ALG. WE NOTE THE GUSTS ARE CAPPED ARD 26 KTS PARTS OF SE MASS MON
AFTN.
CONFIDENCE ON THE MON NIGHT DETERMINISTIC DETAILS IS AVG.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
TUESDAY...
HIGH CONFIDENCE IN A BLUSTERY AND CHILLY DAY BEHIND THE COLD FRONT...BUT
CERTAINLY NOTHING EXTRAORDINARY FOR THIS TIME OF YEAR. 850 MB
TEMPERATURES AROUND -7C TO -8C...SHOULD HOLD HIGH TEMPERATURES IN THE
LOW TO MID 40S ACROSS MOST OF THE REGION. IN FACT...PORTIONS OF THE
INTERIOR HIGH TERRAIN MAY NOT REACH 40. GUSTY NORTHWEST WINDS WILL
MAKE IT FEEL QUITE CHILLY CONSIDERING OUR RECENT WEATHER. SHOULD
GENERALLY BE A DRY DAY...ALTHOUGH A FEW SNOW FLURRIES CAN NOT BE
RULED OUT ACROSS THE HIGHER TERRAIN OF THE DISTANT INTERIOR.
TUESDAY NIGHT AND WEDNESDAY...
WEAK RIDGE OF HIGH PRESSURE WILL TEMPORARILY BUILD INTO THE REGION.
LIGHT WINDS AND MAINLY CLEAR SKIES TUESDAY NIGHT SHOULD ALLOW
OVERNIGHT LOWS TO FALL INTO THE MID TO UPPER 20S ACROSS MUCH OF THE
REGION...WITH LOW TO MID 30S EXPECTED IN DOWNTOWN BOSTON/PROVIDENCE.
HIGHS ON WEDNESDAY SHOULD RECOVER INTO THE 45 TO 50 DEGREE
RANGE...BUT IT WILL FEEL QUITE A BIT MILDER THAN TUESDAY WITH LESS
WIND.
WEDNESDAY NIGHT AND THURSDAY..
ALL THE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT A STRONG LOW
PRESSURE SYSTEM DEVELOPING OVER THE SOUTHERN U.S. WILL TRACK
NORTHEAST AND IMPACT OUR REGION. THE MODELS CONTINUE TO BOUNCE AROUND
QUITE A BIT WITH THEIR TRACK SHIFTING WILDLY FROM RUN TO RUN. ALL
OF THE 12Z RUNS HAVE SHIFTED CONSIDERABLY FURTHER WEST BACK TO WHAT
THEY WERE SHOWING 36 HOURS AGO. IN FACT...ALL THE 12Z MODELS TAKE A
DEEPENING SURFACE LOW WELL WEST OF SOUTHERN NEW ENGLAND. THE MODELS
STILL MAY CERTAINLY BOUNCE AROUND SOME MORE AND WE DO NOT WANT TO
LOCK INTO A SOLUTION AT THIS POINT. HOWEVER...WE ARE CLOSE ENOUGH
TO START LEANING TO MORE OF AN INLAND SOLUTION DESPITE THE FACT THAT
WE MAY EVENTUALLY SOME SECONDARY DEVELOPMENT NEAR THE COASTAL PLAIN.
THIS LOOKS TO BE ONE OF THOSE MORE RARE OCCASIONS WHERE THE IMPACT
FROM THIS STORM WILL LIKELY BE MUCH GREATER WITH A FURTHER INLAND
TRACK...IN TERMS OF STRONG WINDS AND POTENTIALLY COASTAL FLOODING
ALONG THE SOUTH COAST THURSDAY MORNING. WE WILL EXPLAIN A FEW
PARAGRAPHS BELOW.
DESPITE THE VARIANCE IN TRACK...CONFIDENCE IS HIGH ENOUGH TO RUN
WITH HIGH END LIKELY POPS WEDNESDAY NIGHT AND THURSDAY. TIMING IS
WHAT PREVENTS US FROM GOING WITH CATEGORICAL POPS AT THIS TIME...BUT
CONFIDENCE IS RELATIVELY HIGH THAT A PERIOD OF HEAVY RAIN WILL
AFFECT THE REGION. THE SYSTEM APPEARS TO BE MOVING TOO FAST FOR
SIGNIFICANT FLOODING...BUT TYPICAL POOR DRAINAGE STREET FLOODING IS
LIKELY. THE NEXT SHIFT MAY WANT TO CONSIDER UPGRADING POPS TO
CATEGORICAL.
AS FOR PRECIPITATION TYPE...THIS LOOKS TO BE AN ALL RAIN EVENT FOR
SOUTHERN NEW ENGLAND. ANY THREAT FOR A BIT OF WET SNOW ACROSS THE
DISTANT INTERIOR APPEARS TO BE FADING...AND IS A VERY LOW
PROBABILITY AT THIS POINT.
OUR MAIN CONCERNS FOR THIS EVENT WILL REVOLVE AROUND THE POTENTIAL
FOR STRONG WINDS AND PERHAPS EVEN COASTAL FLOODING ALONG THE SOUTH
COAST THURSDAY MORNING. HOWEVER...CONFIDENCE IN THESE TWO POTENTIAL
SCENARIOS REMAINS AVERAGE. IN ORDER FOR COASTAL FLOODING ALONG THE
SOUTH COAST AND STRONG WINDS TO OCCUR...THE LOW WOULD HAVE TO PASS
WEST OF THE REGION ALLOWING THE REGION TO WARM SECTOR. THE 12Z
MODELS ARE POINTING TO THIS POTENTIAL SCENARIO BUT STILL A WAYS OUT
SO ITS NOT SET IN STONE. THE HIGHEST PROBABILITY FOR THE STRONG
WINDS WILL BE ALONG THE COASTAL PLAIN...BUT CAN NOT BE RULED OUT
ACROSS THE REST OF THE REGION DEPENDING UPON HOW FAR WEST THE LOW
TRACKS. FINALLY...A FEW EMBEDDED THUNDERSTORMS ARE POSSIBLE IN THE
WARM SECTOR THURSDAY MORNING BUT TOO MUCH UNCERTAINTY TO INSERT INTO
THE FORECAST THIS FAR OUT.
FRIDAY THROUGH SUNDAY...
MAINLY DRY BUT CHILLY WEATHER APPEARS TO BE IN THE CARDS AS UPPER
TROUGH SETSUP OVER SOUTHERN NEW ENGLAND. GENERALLY EXPECTING HIGHS
IN THE UPPER 30S TO MID 40S ACROSS THE REGION. THIS FORECAST IS 5
TO 7 DAYS INTO THE FUTURE AND OF COURSE SUBJECT TO CHANGE.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
TONIGHT...VFR...BUT LOWERING CIGS AND LOW PROB MVFR CONDITIONS IN
DEVELOPING SHOWERS EEN TO THE NW BAF AFTER 10Z. CONFIDENCE ABV AVG.
MON...BRIEF PERIOD OF MVFR CONDS IN BAND OF SHOWERS MOVING ACROSS THE
REGION. SW GUSTS TO 25 KT POSSIBLE FMH-HYA-ACK. WE MAY SEE IFR CONDS
DEVELOPING VCNTY ORH MIDDAY MONDAY IN SHOWERS... AND THEN BECOMING
EVIDENT FM PVD TO FMH/HYA ARD 21Z MONDAY "IF" SHOWERS DEVELOP AND EXPAND
IN COVERAGE AND INTENSITY ACROSS SNE AS WE ARE CURRENTLY FCSTG.
CONFIDENCE ON MVFR/IFR CIGS/VSBY FCST BELOW AVG. CONDS COULD BE VFR
IF SHOWERS ARE LESS THAN .10 IN SNE.
MONDAY NIGHT...IFR CONDS KACK KFMH AND KHYA /POSSIBLY PVD?/ DURING
THE EVENING BECOMING VFR WHILE ALL OTHER TAF SITES VFR. NW WINDS
G15-25 KTS BOS PVD ORH HYA ACK AND FMH IN CAA. CONFIDENCE ON IFR
CIGS/VSBYS IS BELOW AVG.
OUTLOOK /TUESDAY THROUGH FRIDAY/...
TUESDAY AND WEDNESDAY...MAINLY VFR BUT SOME MARGINAL MVFR CEILINGS
ARE POSSIBLE DURING THE DAY TUESDAY ACROSS THE DISTANT INTERIOR.
WEDNESDAY NIGHT AND THURSDAY...A SIGNIFICANT STORM WILL LIKELY BRING
MVFR-IFR CONDITIONS LATE WEDNESDAY NIGHT/THURSDAY IN HEAVY RAIN
ALONG WITH THE POTENTIAL FOR A PERIOD OF STRONG WIND GUSTS TO
PORTIONS OF THE REGION.
FRIDAY...LOW CONFIDENCE THIS FAR OUT BUT CONDITIONS SHOULD IMPROVE
TO MARGINAL MVFR/VFR.
&&
.MARINE...
TONIGHT...LOW LEVEL SW FLOW INCREASES LATE AND SCA WINDS MAY DEVELOP
LATE SOUTH COASTAL WATERS. BUILDING SEAS SOUTH COASTAL WATERS. SCA
SEAS CONTINUE SE OUTER WATERS. BUOY 44097 SW OF MVY REPORTING 5 FT
SEAS AS OF 10 PM.
MONDAY...BETTER CHANCE OF SCA WINDS WITH BRIEF MIDDAY G25-30 KT AS
SW LLJ INCREASES AND MILD TEMPS OVER THE WATER SUPPORTS SOME MIXING.
SEAS BUILD OVER OUTER SOUTHERN WATERS.
MONDAY NIGHT...SCA ANTICIPATED MANY WATERS IN A PRD OF CAA BUT CONFIDENCE
LESS THAN 80 PCT AND SO SCA NOT ISSUED ATTM. THERE IS MODEL DISAGREEMENT
REGARDING THE STRENGTH OF THE CAA GUSTS...12Z EC AND 18Z NAM BEING
WEAKER THAN WOULD PREFER FOR A 3RD PERIOD ISSUANCE OF THE SCA.
OUTLOOK /TUESDAY THROUGH FRIDAY/...
TUESDAY AND TUESDAY NIGHT...SCA ADVISORY WINDS EXPECTED FOR MOST OF
OUR WATERS WITH WESTERLY FLOW AND DECENT MIXING. SCA FOR ROUGH SEAS
ARE EXPECTED OVER THE OUTER-WATERS.
WEDNESDAY...SEAS AND WINDS SHOULD DROP BELOW SCA FOR A TIME AS A
WEAK RIDGE OF HIGH PRESSURE TEMPORARILY BUILDS OVER THE MID ATLANTIC.
WEDNESDAY NIGHT AND THURSDAY...CONFIDENCE IS MODERATE TO HIGH THAT A
STRONG LOW PRESSURE SYSTEM WILL BRING A PERIOD OF SOUTHERLY GALE
FORCE WINDS AND HIGHS SEAS TO OUR WATERS LATE WEDNESDAY NIGHT AND
THURSDAY.
THURSDAY NIGHT AND FRIDAY...CONFIDENCE REMAINS MODERATE TO HIGH THAT
STRONG SCA TO GALE FORCE WESTERLY WIND GUSTS WILL OCCUR BEHIND THE
DEPARTING STORM SYSTEM. HIGH SEAS WILL LIKELY CONTINUE ACROSS OUR
SOUTHERN OUTER-WATERS.
&&
.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.
CURRENTLY...WE ARE FORECASTING A LOW OF 33 DEGREES ON THE MORNINGS OF
12/1 AND 12/2. AVERAGE FIRST DATE OF 32 IN BOSTON IS AROUND NOVEMBER
4TH. HAYDEN POINTED OUT THAT DESPITE THE POTENTIAL LATEST OCCURRING
FREEZING TEMP AT BOSTON... WE DID ESTABLISH THE 3RD EARLIEST MINOR
SNOWFALL AT LOGAN AIRPORT THIS FALL ON OCTOBER 18TH.
NOVEMBER WILL BE TOP 10 WARMEST... STATUS THRU 11/28
THERE ARE NO PROJECTIONS AS TO FINAL OUTCOME BUT A RANKING IN THE TOP
10 WARMEST IS ASSURED FOR MOST OR ALL OF THESE 100 PLUS YEAR LOCATIONS.
RECENT TOP 10 WARMEST WAS 2006...ONE OF THE WARMEST NOVEMBERS ON
RECORD.
BELOW IS THE CURRENT AVG FOR THE MONTH FROM OUR PRELIMINARY CF6...AS
WELL AS THE DEPARTURE FROM NORMAL...THE TOP 10 WARMEST RANKING AND
CLOSE WITH THE 2006 WARMEST NOV RANKING REFERENCE.
BOS 48.9 PLUS 3.7 RANKED A STRONG NUMBER 6 2006 WAS 4TH WARMEST
BDL 46.5 PLUS 4.4 RANKED NUMBER 5 2006 WAS 4TH WARMEST
PVD 49.0 PLUS 4.9 RANKED A SOLID NUMBER 3. 2006 WAS 2ND WARMEST.
ORH 44.8 PLUS 4.8 RANKED NUMBER 4. 2006 WAS WARMEST EVER NOV
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR ANZ254>256.
SMALL CRAFT ADVISORY FROM 3 AM MONDAY TO 5 AM EST TUESDAY FOR
ANZ235-237.
&&
$$
SYNOPSIS...DRAG/FRANK
NEAR TERM...GAF
SHORT TERM...KJC/DRAG
LONG TERM...FRANK
AVIATION...DRAG/FRANK/GAF
MARINE...DRAG/FRANK/GAF
CLIMATE...DRAG
