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Area Forecast Discussion
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000
FXUS61 KBOX 271815
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
215 PM EDT WED AUG 27 2014

.SYNOPSIS...
HIGH PRESSURE OFFSHORE WILL DRAW WARMER AIR ACROSS NEW ENGLAND
TODAY WITH HIGHS AROUND 90 FOR MANY LOCATIONS. A COLD FRONT WILL
THEN SWEEP THROUGH DURING THE LATE AFTERNOON AND EARLY
NIGHT...BRINGING WIDELY SCATTERED SHOWERS AND THUNDERSTORMS. DRY
AND COOLER CONDITIONS RETURN THURSDAY AND FRIDAY BEHIND THE FRONT.
HURRICANE CRISTOBAL WILL PASS WELL OFFSHORE LATE TONIGHT INTO
THURSDAY MORNING...BUT WILL BRING LARGE SURF AND DANGEROUS RIP
CURRENTS TO SOUTH FACING OCEAN BEACHES. A FRONT MAY STALL ACROSS
NEW ENGLAND...BRINGING UNSETTLED CONDITIONS SUNDAY INTO EARLY NEXT
WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

2 PM UPDATE...

TEMPERATURES...

FINALLY HIT 90 DEGREES AT LOGAN AT 139 PM THIS AFTERNOON. LAST
OCCURRENCE WAS 7/23 WHEN IT WAS 92. NOT MUCH CHANGE FROM PREVIOUS
FORECAST OTHER THAN INCREASING HIGHS BY A FEW DEGS. A MODEST SW
WIND 10 TO 20 MPH IS HELPING TO TAKE THE EDGE OFF THE HEAT ALONG
WITH DEW PTS REMAINING BELOW 70. 

CONVECTION...

12Z NAM ALONG WITH LATEST HRRR AND RAP13 HAVE REALLY BACKED OFF ON
CONVECTIVE QPF AND HAVE DIMINISHED THE EASTWARD TREND...KEEPING
THE BULK OF ANY ACTIVITY ACROSS WESTERN NEW ENGLAND LATER THIS
AFTERNOON AND EVENING. THIS SEEMS REASONABLE GIVEN MARGINAL
INSTABILITY /500-1000J-KG/ ALONG WITH DEEP LAYER SHEAR AND JET
DYNAMICS ARRIVING 00Z-06Z...WELL AFTER PEAKING HEATING. THIS MAY
BE ABLE TO SUSTAIN SOME SHOWERS INTO THE COASTAL PLAIN THIS
EVENING BUT THUNDER NOT LIKELY. WORSE CASE SCENARIO REMAINS AN
ISOLATED STRONG T-STORM POSSIBLE WESTERN CT/MA WITH BRIEF GUSTY
WINDS AND HEAVY DOWNPOURS. 

HIGH SURF...

FIRST SET OF SWELLS /SWELL FRONT/ APPEAR TO BE ON THE EDGE OF
ENTERING SOUTHERN NEW ENGLAND WATERS...WITH BUOY 44097 SOUTHEAST
OF BLOCK ISLAND NOW REPORTING 4 FT SWELLS EVERY 12 SECONDS. THIS
SHOULD RESULT IN SURF BUILDING RAPIDLY LATER THIS AFTERNOON AND
ESPECIALLY TOWARD SUNSET AT SOUTH AND SOUTHEAST FACING OCEAN
BEACHES. 

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
TONIGHT...
CONSENSUS OF THE MODEL SOLUTIONS BRINGS THE COLD FRONT TO THE
COASTAL PLAIN AROUND SUNSET AND OFFSHORE EARLY TONIGHT. EXPECT
LINGERING SHOWER/TSTM THROUGH 10 PM IN RI AND EASTERN MASS...AND
THROUGH MIDNIGHT CAPE AND ISLANDS. WINDS TURN NORTHWEST BEHIND THE
COLD FRONT AND DRAW COOLER DRIER AIR DOWN FROM CANADA. THIS WILL
MEAN CLEARING SKIES AND DEW POINTS IN THE 50S AND LOWER 60S.
SWELL FROM HURRICANE CRISTOBAL CONTINUES TO INCREASE...WITH 5 FOOT
SWELL MOVING INTO OUR SOUTHERN WATERS EARLY TONIGHT. WE HAVE
ISSUED A HIGH SURF ADVISORY STARTING TONIGHT.

THURSDAY...
UPPER SHORTWAVE MOVES ACROSS NEW ENGLAND WITH BRIEF COOLING ALOFT.
MOISTURE FIELDS SHOW LINGERING 80 PCT RH VALUES BETWEEN 800 AND
900 MB. THIS SUGGESTS DIURNAL CUMULUS WILL FORM DURING THE DAY.
MIXING WILL REACH TO 850 MB WHERE TEMPS OF 10-12C WOULD SUPPORT
MAX SFC TEMPS IN THE UPPER 70S AND LOW 80S. WINDS ALOFT WITHIN THE
MIXED LAYER ARE FORECAST AT 20 KNOTS...WHICH MAY GET MIXED TO THE
SURFACE IN GUSTS.

HIGH SURF WILL CONTINUE THROUGH THE DAY AS CRISTOBAL PASSES WELL
OFFSHORE. THE HIGH SURFACE ADVISORY WILL CONTINUE THROUGH THE DAY.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...

* COOL AND DRY WEATHER UNDER HIGH PRESSURE FRIDAY
* WARM AND HUMID CONDITIONS INTO THE WEEKEND 
* SCT SHOWERS/THUNDERSTORMS SUNDAY INTO EARLY NEXT WEEK

OVERVIEW AND MODEL PREFERENCES...
MEDIUM RANGE MODELS AND THEIR ENSEMBLES ALL CONTINUE TO SIGNAL A
LOW AMPLITUDE UPPER LEVEL PATTERN ACROSS THE NORTHERN TIER
STATES... WHICH GENERALLY MEANS A FAST MOVING PATTERN IN PLACE.
NOTING A DECENT SHORT WAVE DEVELOPING ACROSS THE GREAT LAKES LATE
THIS WEEK...THEN PUSHING ALONG IN THE GENERAL W-NW UPPER FLOW
TOWARD NEW ENGLAND. A FRONT ALSO TRIES TO SHIFT S...BUT BECOMES
PARALLEL TO THIS UPPER FLOW...SO MAY SEE UNSETTLED CONDITIONS MOVE
IN FOR SUNDAY AND LABOR DAY. NOTING INCREASING VARIANCE AMONGST
THE OP MODEL RUNS EARLY NEXT WEEK IN TRYING TO CLEAR THE SHORT
WAVE...WITH POSSIBLY ANOTHER WEAKER ONE MOVING IN.

LEANED TOWARD A BLEND OF AVAILABLE MODELS FOR THE EARLY PORTION OF 
THE FORECAST...WHICH SHOWED GOOD CONTINUITY AND RUN TO RUN 
CONSISTENCY OVER THE LAST SEVERAL MODEL RUNS...THEN TRENDED TOWARD 
THE GFS/EC ENSEMBLES BEGINNING SUNDAY THROUGH TUESDAY. 
 
DETAILS...

THURSDAY NIGHT THROUGH FRIDAY NIGHT... 
EXPECT DRY AND COOL CONDITIONS AS LARGE HIGH PRES BUILDS OUT OF
THE GREAT LAKES...SHIFTING E IN THE BROAD UPPER LEVEL WESTERLY
WIND FLOW. WILL MAINLY CLEAR SKIES THU NIGHT AND WINDS BECOMING
LIGHT/VRBL MAINLY AFTER MIDNIGHT...TEMPS WILL TUMBLE...WITH
READINGS AWAY FROM THE IMMEDIATE COAST AND URBAN CENTERS DROPPING
TO THE MID 40S TO AROUND 50. SOME DIURNAL CLOUDS WILL DEVELOP
DURING FRIDAY...BUT IT WILL REMAIN COOL WITH HIGHS MAINLY IN THE
LOWER-MID 70S. NW WINDS MAY GUST UP TO AROUND 20 KT DURING THE
AFTERNOON.

CONDITIONS WILL REMAIN DRY FRI NIGHT...BUT THE HIGH WILL CREST 
ACROSS THE REGION OVERNIGHT. EXPECT SOME MID AND HIGH LEVEL CLOUDS 
WORKING IN WITH LOWS IN THE 50S. 

SATURDAY...
TRANSITION DAY AS H5 SHORT WAVE MOVES OUT OF THE GREAT LAKES.
TEMPS WILL REBOUND AS W-SW WINDS KICK IN...BRINGING IN THE MILDER
CONDITIONS WITH INCREASING HUMIDITY ESPECIALLY LATE IN THE DAY
INTO SAT NIGHT. A FRONT WILL BEGIN TO SLOWLY SHIFT S OUT OF QUEBEC
AND S ONTARIO...SO MAY START TO SEE SOME SHOWERS MOVE INTO WESTERN
AREAS SAT NIGHT. CARRIED ONLY LOW CHANCE POPS AT THIS POINT. HIGHS
WILL BE IN THE 70S...UP TO AROUND 80 IN THE CT AND MERRIMACK
VALLEYS.

SUNDAY THROUGH MONDAY...
WITH THE HIGH ANCHORED OFF THE MID ATLC AND SE U.S. COAST...ALONG
WITH GENERAL W WIND FLOW ALOFT...THE FRONT THAT TRIES TO PUSH S
WILL GET HUNG UP IN THIS UPPER FLOW. THE SHORT WAVE WILL MOVE
ALONG THE FRONT...SO WILL SEE SCT SHOWERS PUSH ACROSS SUNDAY INTO
THE HOLIDAY...WITH BEST SHOT SUNDAY NIGHT AND MON MORNING. DEWPTS
ALSO INCREASE. PWATS WILL ALSO INCREASE...ON ORDER OF 1.7 TO 1.8
INCHES /ABOUT +2 SD FOR LATE AUGUST/. SOME MARGINAL INSTABILITY
ALSO WORKS IN...SO CAN NOT RULE OUT SOME THUNDERSTORMS. MAY ALSO
SEE A FEW PRODUCING LOCALLY HEAVY RAINFALL.

TEMPS WILL RISE TO THE UPPER 70S TO MID 80S...MILDEST ON 
SUNDAY...WITH DEWPTS RISING TO THE MID 60S BOTH DAYS.

TUESDAY...
SOME QUESTION AS TO TIMING OF EXIT OF PRECIP...AND WHETHER
ANOTHER SHORT WAVE DEVELOPS AND PUSHES TOWARD THE REGION. FOR
NOW...EXPECT MAINLY DRY BUT WARM CONDITIONS...BUT NOT A LOT OF
CONFIDENCE FOR THIS PORTION OF THE FORECAST.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT. 
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

SHORT-TERM /TODAY THROUGH THURSDAY/...MODERATE CONFIDENCE.

THRU 00Z...ANY -TSRA NOT FIRING UNTIL 20Z/21Z WESTERN NEW ENGLAND
WITH CHANCES FARTHER EAST FADING TOWARD 00Z. ACTIVITY WILL BE
ISOLATED OR WIDELY SCATTERED. VFR PREVAILS WITH LOW RISK OF BRIEF
MVFR IN -TSRA.

AFTER 00Z...ISOLATED TO WIDELY SCATTERED SHOWERS TIL 06Z THEN
MOVING OFFSHORE WITH FRONTAL PASSAGE AND WIND SHIFT FROM SW TO NW
06Z-12Z FROM NW TO SE. VFR PREVAILS WITH BRIEF MVFR POSSIBLE IN
ANY HEAVIER SHOWERS. LOW RISK OF BRIEF IFR SOUTH COAST UNTIL
FRONTAL PASSAGE 06Z-12Z. 

THURSDAY...VFR. NORTHWEST WINDS MAY GUST TO 20 KNOTS WITH
SCATTERED TO BROKEN SKY COVER AROUND 5000 FEET FROM MIDDAY TO
EVENING.

THU NIGHT...VFR AND DRY WITH A MODEST NW WIND 10-20 KT DIMINISHING
TOWARD MORNING.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF. ISOLATED -SHRA/-TSRA 22Z-
04Z POSSIBLE. GIVEN LIMITED AREAL COVERAGE DECIDED NOT TO INCLUDE
VCTS AND JUST GO WITH VCSH...THE HIGHER PROBABILITY.

KBDL TERMINAL...HIGH CONFIDENCE IN TAF. ISOLATED -SHRA/-TSRA
21Z-03Z.  GIVEN LIMITED AREAL COVERAGE DECIDED NOT TO INCLUDE
VCTS AND JUST GO WITH VCSH...THE HIGHER PROBABILITY.

OUTLOOK...FRI THROUGH SUNDAY...

FRIDAY...HIGH CONFIDENCE. VFR WITH SKC THURSDAY NIGHT INTO
FRIDAY. LIGHT WINDS. PATCHY FOG AFTER 06Z FRI WITH LOCAL MVFR TO
IFR CONDITIONS POSSIBLE IN NORMALLY PRONE AREAS. SEA BREEZES
FRIDAY.

SATURDAY INTO SUNDAY...MODERATE CONFIDENCE.
VFR. INCREASING S-SW WINDS. BETTER CHANCES FOR SHRA/TSRA SUNDAY
ACROSS THE INTERIOR.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT. 
MODERATE...30 TO 60 PERCENT. 
HIGH...GREATER THAN 60 PERCENT.

SHORT-TERM /TODAY THROUGH THURSDAY/...HIGH CONFIDENCE.

2 PM UPDATE...

3-5 FT SOUTHERLY SWELLS WITH A PERIOD OF 12 SECONDS AT BUOY 44097
SOUTHEAST OF BLOCK ISLAND. THUS SWELLS FROM CRISTOBAL HAVE ENTERED
SOUTHERN NEW ENGLAND WATERS. EARLIER DISCUSSION BELOW.

============================================================

TODAY...HIGH PRESSURE OVER THE WATERS WILL SHIFT FARTHER OFFSHORE.
EXPECT LIGHT WINDS/PATCHY FOG FIRST THING THIS MORNING...OTHERWISE
GOOD VSBY WITH SOUTHWEST WINDS 10-15 KNOTS. AN APPROACHING COLD
FRONT MAY BRING SCATTERED SHOWERS/TSTMS TOWARD EVENING.

TONIGHT...INCREASING SOUTH SWELL FROM HURRICANE CRISTOBAL. THE
SOUTHERN WATERS WILL EXPERIENCE A 5 FOOT SWELL IN THE EARLY NIGHT
AND 6 TO 8 FOOT SWELL BY MORNING.

THURSDAY...SOUTH SWELL CONTINUES THROUGH THE DAY WITH 6 TO 9 FOOT
SEAS...MAINLY SWELL...ON THE SOUTHERN WATERS. NORTHWEST WIND WILL
BE GUSTY NEAR SHORE WITH MAXIMUM GUSTS AROUND 20 KNOTS.

OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...

THURSDAY NIGHT...HIGH CONFIDENCE.
EXPECT S SWELL FROM HURRICANE CRISTOBAL TO CONTINUE THROUGH THE
NIGHT...THOUGH MAY START TO SUBSIDE LATE. SEAS UP TO 7-9 FT ON THE
OUTER WATERS. N-NW WIND GUSTS UP TO 20 KT ON THE EASTERN OUTER
WATERS.

FRIDAY...HIGH CONFIDENCE. 
N WINDS GUSTING TO 20 KT EARLY...THEN WILL VEER TO E-NE AND
DIMINISH DURING THE DAY. SEAS MAY LINGER AT AROUND 5 FT ON THE
OUTER WATERS DURING THE DAY BEFORE SUBSIDING.

SATURDAY AND SUNDAY...MODERATE CONFIDENCE. 
WINDS BECOME S-SW DURING SAT AND CONTINUE THROUGH SUN. GUSTS
SHOULD REMAIN BELOW SMALL CRAFT CRITERIA...BUT SEAS MAY BUILD UP
TO AROUND 5 FT ON THE SOUTHERN OUTER WATERS.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...AIR QUALITY ALERT UNTIL 9 PM EDT THIS EVENING FOR CTZ002>004.
MA...HIGH SURF ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT THURSDAY 
     FOR MAZ020-022>024.
NH...NONE.
RI...HIGH SURF ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT THURSDAY 
     FOR RIZ006>008.
     AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR RIZ001>005.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 PM THIS 
     AFTERNOON TO 8 PM EDT THURSDAY FOR ANZ235-237-254>256.

&&

$$
SYNOPSIS...WTB/EVT
NEAR TERM...NOCERA
SHORT TERM...WTB
LONG TERM...EVT
AVIATION...NOCERA/EVT
MARINE...WTB/EVT



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