FXUS61 KBOX 271507
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1007 AM EST FRI NOV 27 2009
.SYNOPSIS...
A COASTAL STORM DEVELOPING SOUTH OF NANTUCKET WILL RAPIDLY INTENSIFY
AS IT TRACKS NORTHWARD INTO THE GULF OF MAINE THIS AFTERNOON AND
THEN INTO THE MARITIMES TONIGHT AND SATURDAY. HIGH PRESSURE WILL
BRING DIMINISHING WINDS AND MILDER CONDITIONS SUNDAY. A COLD FRONT
MOVES ACROSS THE AREA BRINGING SHOWERS MONDAY AND MONDAY
NIGHT...FOLLOWED BY COOLER AND DRIER WEATHER TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1006A UPDATE:
BOX STP HIGHLY OVER PREDICTED IN CT SW ORH CTY DUE TO BRIGHT BANDING.
ALSO...TIDES RESENT...BIG SURGE OF ~1.5 FT...ONLY MODEL PREDICTED .5
TO .7 FT ATTM. INCREASED SURGE AND STORM TIDE THROUGH TONIGHT BUT ITS
NOT A FACTOR DUE TO LOW ASTRO. THIS A CONTG PROBLEM WITH MRPSSE FCSTS
...PREDICTING HALF OF THE REALTIME STORM SURGE ON ONSHORE FLOW LOW
PRES EVENTS.
THUNDER: NO LIGHTNING YET. HIGH REFLECTIVITY IN E MASS CW SO FAR BLO
THE ICING LVL/LIGHTNING THRESHOLD.
918 AM: BL APPEARS JUST TOO WARM TO SUPPORT A BAND OF HEAVY WET SNOW
TODAY IN THE FGEN REGION OF E CT CENTRAL MA AND MONADNOCKS BUT WE ARE
MONITORING. BRIGHT BANDING DEVELOPING CT ATTM AS EITHER SLEET OR BIG
WET FLAKES ALOFT ARE MELTING IN THE BL. WILL MONITOR BUT FCST WITH
SLEET IN IT FOR NOW THIS MORNING IS OK. WILL THERE BE THUNDER? RAW
FCST PARAMETERS SUGGEST A SMALL CHC E MASS CW THIS MORNING BUT SOMETIMES
THIS OCCURS IN THE MAX FGEN REGION AND SO WE CUD SEE ISO THUNDER
DEVELOP LATE THIS MORNING IN CT OR CENTRAL MA BUT FOR NO SUBSTANTIAL
CHANGES TO THE 845 AM UPDATE.
845 AM: UPDATE HAS SLEET ADDED IN THIS MORNING FOR CT...W 1/2 MA AND
SW NH. ADJUSTED TEMPS/FOG A BIT TOO...DUE TO INCREASING CONVERGENT
FLUXES WITH BL COOLING MIXING.
REMAINDER BLO FROM EARLIER THIS MORNING..
COASTAL STORM SOUTH OF ACK WILL UNDERGO RAPID CYCLOGENESIS THROUGH
TODAY IN RESPONSE TO FAVORABLE JET DYNAMICS AND 200-240M HEIGHT FALL
CENTER MOVING OFF THE COAST. MID LEVEL TROF BECOMES NEG TILTED WHICH
FORCES STORM TO HUG NEW ENG COAST AND MOVE NWD INTO GULF OF MAINE
THIS AFTERNOON.
RAIN OVERSPREAD SNE EARLY THIS MORNING AND WILL CONTINUE TO MOVE NWD.
DRY SLOT MOVES ACROSS THE COASTAL PLAIN AFT 12Z WHICH WILL ALLOW THE
RAIN TO TAPER OFF IN THIS REGION THIS MORNING...BUT CANT RULE OUT A
FEW TSTMS ALONG AND E OF I95 CORRIDOR FROM BOS-PVD ON THE EDGE OF THE
DRY SLOT. NAM/GFS BOTH SHOW STRONG ELEVATED THUNDER SIGNAL WITH TT IN
LOW TO MID 50S AND UNSTABLE SWI.
STEADIER RAIN WILL SHIFT TO THE INTERIOR AND CONTINUING INTO THE
AFTERNOON AS DEFORMATION BAND SETS UP ALONG AND WEST OF THE DEEPENING
MID LEVEL CENTER. WE THINK THE NAM IS CAPTURING THIS COMMA HEAD
PRECIP THIS AFTERNOON BETTER THAN THE GFS. AS STORM INTENSIFIES AND
UPPER LOW MOVES OVERHEAD...DYNAMIC COOLING WILL COOL THE COLUMN AND
MAY SEE A MIX/CHANGE TO SNOW OVER THE HIGHER ELEVATIONS OF THE
BERKS...MONADNOCKS AND NORTHERN ORH HILLS THIS AFTERNOON. NAM IS MOST
AGGRESSIVE WITH THIS COOLING AND WOULD SUGGEST AT LEAST A FEW INCHES
ABOVE 1000 FT...BUT GFS IS SLOWER WITH THE COOLING WITH MINIMAL
ACCUM. WE HAVE INDICATED A MIX OF RAIN/SNOW OVER THE HIGHER TERRAIN
BUT NO ACCUM YET. HOWEVER...DONT THINK WE CAN COMPLETELY DISCOUNT THE
NAM SOLUTION AS SREF IS SHOWING INCREASING POPS FOR FOR 1" AND 4"
OVER SW NH. DAY SHIFT WILL NEED TO EVALUATE THIS FURTHER.
AS THE STORM MOVES TO THE NORTH...WINDS WILL SHIFT TO THE WEST AND
INCREASE THIS AFTERNOON...FIRST ALONG THE SOUTH COAST THEN SPREADING
NORTH. HOWEVER...THE STRONGEST WINDS WILL OCCUR TONIGHT.
MAX TEMPS WILL OCCUR THIS MORNING WITH COOLING TEMPS THIS
AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
VERTICALLY STACKED LOW WILL SLOWLY DRIFT EWD FROM GULF OF MAINE
TONIGHT. AREA OF DEEPER MOISTURE AND OMEGA ROTATING AROUND THE
UPPER LOW WILL SWING THOUGH SNE TONIGHT AND LIKELY BRING ANOTHER
PERIOD OF SHOWERS...WITH MIXED RAIN/SNOW HIGHER TERRAIN. MINOR
ACCUM POSSIBLE IN THE NW HIGHER TERRAIN. SFC TEMPS MAY HOLD STEADY
OR EVEN SLOWLY RISE TONIGHT AS MID LEVEL COLD POOL MOVES EWD.
AFTER COORD WITH SURROUNDING OFFICES...WE EXPANDED THE WIND ADVISORY
FOR ALL SNE FOR TONIGHT AS LOW LEVEL WIND FIELD INCREASES WITH 40-45
KT DOWN TO 925 MB. GFS IS MORE BULLISH THAN THE NAM ON THE STRONG
WIND POTENTIAL. STRONGEST WINDS WILL LIKELY BE NEAR THE COAST WHERE
BEST MIXING...WITH SECONDARY MAX POSSIBLE OVER THE HIGHER TERRAIN.
MODERATE TO HIGH CONFIDENCE FOR WIND ADVSY NEAR THE COAST WITH LOWER
CONFIDENCE IN THE INTERIOR.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
VERTICALLY STACKED LOW PRESSURE OVER THE MARITIMES CONTINUES MOVING
NORTH SATURDAY. THE LOW WILL BE LED BY PRESSURE FALLS OF 2 MB PER
HOUR AND TRAILED BY PRESSURE RISES OF 1 MB PER HOUR. THAT WILL MEAN
CONTINUED STRONG WINDS FOR AT LEAST THE START OF SATURDAY...WITH
WINDS THEN DIMINISHING LATE IN THE DAY AS THE STRONGEST RISES MOVE
INTO THE MARITIMES. THERE WILL ALSO BE SUFFICIENT COLD ADVECTION TO
PROMOTE MIXING OF STRONGER GUSTS FROM 3000-4000 FEET. WINDS AT THAT
LEVEL REACH 40 TO 45 KNOTS WITH WINDS 50 TO 60 KNOTS JUST ABOVE THE
EXPECTED MIXING HEIGHT. THE WIND ADVISORY WILL CONTINUE THROUGH AT
LEAST MIDDAY SATURDAY...BEST BETS FOR WINDS WOULD BE OVER THE CAPE
AND ISLANDS AND OVER THE HIGHER ELEVATIONS OF THE INTERIOR.
WINDS DIMINISH SATURDAY NIGHT AND SUNDAY AS HIGH PRESSURE BUILDS OVER
THE REGION.
THE NEXT WEATHER MAKER WILL BE A COLD FRONT MOVING ACROSS FROM THE
GREAT LAKES. CLOUDS LEADING THE FRONT MAY REACH US LATE SUNDAY...BUT
MOST INCREASE IN CLOUDS WILL OCCUR SUNDAY NIGHT. THE VARIOUS MODELS
HAVE DIFFERENT TIMING FOR THIS FRONT...WITH THE NAM AND GFS FASTER
AND THE ECMWF SLOWER. WITH THE DIGGING OF AN UPPER TROF OVER THE
LAKES AND RESULTING SOUTHWEST FLOW OVER US...WE PREFER THE SLOWER
ECMWF SCENARIO. THIS WOULD BRING THE FRONT THROUGH LATE MONDAY OR
MONDAY NIGHT. EXPECT LIGHT SHOWERS...THE PRECIP TYPE SHOULD MOSTLY BE
RAIN BUT FORECAST THERMAL PROFILES SHOW A POTENTIAL FOR A CHANGE TO
SNOW MONDAY NIGHT AFTER THE COLD FRONT MOVES THROUGH ESPECIALLY IN
THE NORTH AND WEST. THIS COULD BRING AN INCH OR TWO OF SNOW TO THE
BERKSHIRE EAST SLOPES/MONADNOCKS/NORTHERN WORCESTER HILLS.
TUESDAY AND WEDNESDAY LOOK DRY AND COOL AS HIGH PRESSURE MOVES
THROUGH. THE GFS SHOWS ANOTHER COASTAL LOW MOVING PAST ON WEDNESDAY
NIGHT...THE ECMWF BRINGS IT THROUGH ON THURSDAY. WILL FAVOR THE ECMWF
SOLUTION AND FORECAST CHANCE POPS FOR THURSDAY.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
918 AM: ISO THUNDER POSSIBLE IN CT/CENTRAL MA THIS MORNING IN MAX
LIFT REGION WHERE ICE OR LARGE WET SNOWFLAKES ARE OCCURRING ALOFT PER
RADAR AND MODELED TEMPS/FGEN. OTRW ANY T TODAY SHOULD B CONFINED TO
THE E MASS WATERS MIDN OR LATE MORNING INTO EARLY AFTN CLOSER TO THE
LOW LVL INSTABILITY.
845 AM: WIDESPREAD IFR CIGS AND MVFR/IFR VSBYS THIS MORNING AS RAIN
MOVES ACROSS THE REGION. SLEET REPORTS IN ELLINGTON CT AND
SPRINGFIELD MA AREA ARD 815 AM AND PUBLIC PRODUCTS UPDATED.
MAY SEE A MIX WITH SNOW OVER THE HIGHER ELEVATIONS THIS AFTERNOON AND
HAVE INDICATED THIS IN THE ORH TAF. SOME IMPROVEMENT POSSIBLE IN THE
LOWER CT VALLEY AND COASTAL PLAIN THIS AFTERNOON AS WESTERLY WINDS
INCREASE. WEST WIND GUSTS INCREASE TO 25-30 KTS LATER TODAY.
TONIGHT...GUSTY WEST WINDS TO 35-40 KT POSSIBLE...ESPECIALLY HYA-ACK
AND ORH. CONDITIONS SHOULD IMPROVE TO VFR IN THE COASTAL
PLAIN...BUT MVFR PERSISTING IN THE DISTANT INTERIOR...ESPECIALLY
ORH-MHT.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...CONDITIONS IMPROVING TO VFR IN THE MORNING. STRONG
NORTHWEST WINDS THROUGH AT LEAST MIDDAY WITH SUSTAINED WINDS 20 TO 30
KNOTS AND GUSTS 40 TO 45 KNOTS. WINDS WILL DIMINISH LATE SATURDAY.
SUNDAY...VFR.
MONDAY...CIGS LOWERING TO MVFR IN ADVANCE OF A COLD FRONT...AREAS OF
MVFR VSBYS IN SHOWERS.
MONDAY NIGHT...MVFR CIGS WITH SCATTERED MVFR VSBYS IN RAIN
SHOWERS...POSSIBLE SNOW SHOWERS FAR INTERIOR.
TUESDAY...VFR.
&&
.MARINE...
NE WINDS SHIFT TO THE WEST TODAY AS COASTAL STORM TRACKS NORTH OF
THE WATERS. STRONGEST WESTERLY WINDS WILL OCCUR LATER TODAY AND
ESPECIALLY TONIGHT AS LOW LEVEL WINDS INCREASE FROM SOUTH TO NORTH.
GALE WARNING EXPANDED TO ALL WATERS STARTING OVER THE SOUTH COASTAL
WATERS LATER TODAY THAN EASTERN WATERS TONIGHT. GUSTS TO 45 KT
LIKELY OVER THE SOUTH COASTAL WATERS AND 35-40 KT ELSEWHERE. LOW
PROB FOR STORM FORCE WINDS TONIGHT SOUTHERN WATERS.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...NORTHWEST GALES CONTINUE...WITH WINDS DIMINISHING SATURDAY
NIGHT. SEAS BUILDING TO 8 TO 15 FEET ON THE OUTER WATERS...SUBSIDING
AFTER MIDNIGHT.
SUNDAY...WINDS AT SMALL CRAFT ADVISORY LEVEL IN THE MORNING BUT
DROPPING BELOW 25 KNOTS AFTERNOON. SEAS DIMINISH BELOW 5 FEET ON THE
INNER WATERS...BUT REMAIN AT OR ABOVE 5 FEET ON THE OUTER WATERS.
MONDAY-TUESDAY...INCREASING SEAS AND SOUTHWEST WINDS AHEAD OF A COLD
FRONT. WINDS AND SEAS MAY REACH SMALL CRAFT ADVISORY LEVELS.
CONDITIONS CONTINUE IN THE NORTHWEST FLOW BEHIND THE FRONT TUESDAY.
&&
.CLIMATE...
IT IS INTERESTING TO NOTE THAT BOSTON/S LOGAN AIRPORT HAS NOT FALLEN
TO THE FREEZING MARK SO FAR THIS SEASON. THE LATEST IN THE SEASON
THAT BOSTON HAS GONE WITHOUT HITTING 32F WAS DEC 2ND 1975. IT IS
POSSIBLE WE BREAK THAT RECORD...BUT IT WILL BE CLOSE SUNDAY NIGHT...
AND NOT COMPLETELY OUT OF THE QUESTION SATURDAY NIGHT...BUT A LOWER
PROBABILITY THEN.
&&
.EQUIPMENT...
RADAR PROBLEM ON THE WEB SHOULD BE FIXED.
TBOS TDWR CONT OTS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WIND ADVISORY FROM 6 PM THIS EVENING TO NOON EST SATURDAY FOR
CTZ002>004.
MA...WIND ADVISORY FROM 6 PM THIS EVENING TO NOON EST SATURDAY FOR
MAZ002>024-026.
NH...WIND ADVISORY FROM 6 PM THIS EVENING TO NOON EST SATURDAY FOR
NHZ011-012-015.
RI...WIND ADVISORY FROM 6 PM THIS EVENING TO NOON EST SATURDAY FOR
RIZ001>008.
MARINE...GALE WARNING FROM 3 PM THIS AFTERNOON TO 3 PM EST SATURDAY FOR
ANZ232>235-237-255-256.
GALE WARNING FROM 6 PM THIS EVENING TO 3 PM EST SATURDAY FOR
ANZ230-231-236-250-251-254.
&&
$$
SYNOPSIS...WTB/KJC
NEAR TERM...WTB/KJC/DRAG 1004
SHORT TERM...KJC
LONG TERM...WTB
AVIATION...WTB/KJC/DRAG
MARINE...WTB/KJC
CLIMATE...
