-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBOX 152327
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
727 PM EDT WED MAY 15 2013

.SYNOPSIS...
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A COOL FRONT WILL MOVE THROUGH DURING THE NIGHT. DRY AND WARM
WEATHER RETURNS FOR THURSDAY. A WEAK...DRY COLD FRONT WILL
QUICKLY CROSS THE REGION THURSDAY NIGHT...BRINGING COOLER BUT
SEASONABLE CONDITIONS FRIDAY INTO THE WEEKEND. A WARMING TREND IS
LIKELY EARLY NEXT WEEK AS MARITIME HIGH PRESSURE MOVES OFFSHORE.
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&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...

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7 PM UPDATE...
SHOWERS ARE MOVING OFFSHORE. SATELLITE IMAGERY SHOWS CLEARING
MOVING INTO THE CT VALLEY. THIS CLEARING WILL SPREAD ACROSS THE
REMAINDER OF SOUTHERN NEW ENGLAND BY MIDNIGHT. WINDS WILL DIE DOWN
A LITTLE DURING THE NIGHT...AND THIS COULD MAKE ROOM FOR SOME
PATCHY FOG OVERNIGHT ESPECIALLY ALONG THE SOUTH COAST. ADVANCED
THE CLEARING SKIES AND DIMINISHING POPS BY A COUPLE OF HOURS...AND
ADJUSTED TEMPS/DEWPOINTS PER CURRENT OBSERVATIONS.

PREVIOUS DISCUSSION...
H85 TEMPS DO NOT FALL TOO MUCH OVERNIGHT...SO TEMPS WILL BOTTOM
OUT IN THE MID 40S TO AROUND 50.
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&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
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THURSDAY...
NEW ENGLAND REMAINS IN THE BASE OF A BROAD CYCLONIC UPPER
FLOW AS H5 CUTOFF LOW SPINS OVER QUEBEC. EXPECT DRY CONDITIONS
WITH W-SW WINDS IN PLACE. SKIES WILL BE MOSTLY CLEAR AND...ALONG
WITH RATHER STRONG JET IN PLACE UP TO 700 HPA...WILL SEE
EXCELLENT MIXING UP TO 700-800 HPA. W-SW WINDS WILL BE
INCREASING...WITH GUSTS UP TO 35 MPH WITH SOME GUSTS UP TO 40 MPH
AS TEMPS SOAR TO THE MID 70S TO AROUND 80. RELATIVE HUMIDITIES
WILL BE RATHER LOW AS WELL...DOWN TO 20 TO 30 PERCENT...SO
POTENTIAL FOR FIRE WEATHER CONCERNS /SEE FIRE WEATHER SECTION
BELOW/.

THURSDAY NIGHT...
AS UPPER LOW MOVES E...WILL SEE WINDS DIMINISH AS TEMPS FALL BACK.
EXPECT ANOTHER DRY FRONT TO MOVE ACROSS OVERNIGHT WITH LITTLE
MORE THAN A WIND SHIFT TO NW-N. COOLER AIR WILL WORK IN AFTER
MIDNIGHT AS H85 TEMPS FALL BACK TO +1 TO +4C. OVERNIGHT LOWS WILL
FALL BACK TO THE 40S TO AROUND 50.
-- End Changed Discussion --

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
BIG PICTURE...
UPPER TROUGH OVER NEW ENGLAND MOVES OFF THROUGH THE MARITIMES BY
SATURDAY. UPPER RIDGE THEN BUILDS OVER THE EASTERN USA FOR THE
FIRST HALF OF NEXT WEEK. TREND TO A SLOWER MOVING PATTERN DURING
NEXT WEEK.

MODEL PREFERENCES...GENERAL AGREEMENT BETWEEN THE GFS AND ECMWF
ON ON LARGE SCALE MASS FIELDS. DURING NEXT WEEK THE GFS IS MORE
AGGRESSIVE IN BRINGING NORTHERN CANADA UPPER LOW SOUTH TO NEW
ENGLAND...THE ECMWF GETS AROUND TO IT 24 HOURS LATER. WE USED A
BLEND OF HPC AND GMOS GRIDS EXCEPT POPS WERE HAND DRAWN BASED ON
ENSEMBLE COMPARISON OF THE VARIOUS MODEL QPF.

THE DAILIES...

FRIDAY...CYCLONIC FLOW ALOFT WITH COLD POOL PRESENT ALOFT.
HOWEVER DESTABILIZING SHARP LAPSE RATES REMAIN ACROSS MAINE AND
NORTHERN VT/NH. LIMITED MOISTURE 800-850 MB BUT MUCH DRIER ABOVE.
SO WE EXPECT LIMITED DIURNAL CUMULUS BUT OTHERWISE A DRY DAY.
MIXING DEPTHS REACH ABOVE 850 MB...POSSIBLY CLOSE TO 800 MB. WINDS
THROUGH THIS LAYER WILL BE 15 KTS OR LESS. TEMPS IN THE LAYER WILL
SUPPORT LOWER 70S...WITH A LITTLE DEEPER MIXING A FEW SPOTS COULD
REACH MID 70S. SURFACE PRESSURE PATTERN IS SUFFICIENTLY LIGHT TO
ALLOW MIDDAY/AFTERNOON SEABREEZES.

SATURDAY-SUNDAY...HIGH PRESSURE BUILDS OVER THE REGION SATURDAY
AND SHIFTS OFFSHORE SUNDAY. FAIR SKIES SATURDAY. FLOW TURNS
SOUTHEAST SUNDAY WITH MODELS SHOWING MOISTURE INCREASING FROM THE
SOUTH...SO MORE IN THE WAY OF CLOUDS ON SUNDAY BUT WITH DRY
WEATHER.

MONDAY THROUGH WEDNESDAY...UPPER RIDGE BREAKS DOWN DURING THIS
PERIOD. HIGH PRESSURE OFFSHORE SHOULD KEEP US DRY MONDAY. THE GFS
SWINGS A COLD FRONT THROUGH LATE TUESDAY FOLLOWED BY CANADIAN HIGH
PRESSURE BUILDING SOUTH WITH DRY WEATHER WEDNESDAY. THE ECMWF
BRINGS THE FRONT THROUGH ON WEDNESDAY. WE HAVE BROUGHT CHANCE POPS
TO MOST OF THE REGION TUESDAY NIGHT AND WEDNESDAY. WHETHER THE
SLOWER OR FASTER SCENARIO OCCURS...WE EXPECT A WARMING TREND
THROUGH THE FIRST HALF OF THE WEEK WITH COOLING TEMPS AFTER THE
COLD FRONT MOVES THROUGH.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
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FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH THURSDAY NIGHT/...MODERATE TO HIGH
CONFIDENCE.

TONIGHT...MVFR CIGS LINGER BEHIND THE DEPARTING SHOWERS...BUT
SHOULD CLEAR BY MIDNIGHT. AS WINDS DIMINISH OVERNIGHT THERE MAY BE
PATCHY IFR IN FOG ESPECIALLY ALONG THE SOUTH COAST AND COASTAL
LOWLANDS.  FOR MOST PLACES...VFR AFTER CLEARING.

THURSDAY-THURSDAY NIGHT...VFR CONDITIONS. LOW PROB OF MVFR VSBYS
THROUGH 14Z ACROSS CAPE COD AND THE ISLANDS. MAY SEE GUSTY W-SW
WINDS UP TO 35 KT DURING THU...DIMINISHING THU NIGHT.

KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.

KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.

OUTLOOK...FRIDAY THROUGH MONDAY...

GENERALLY VFR DURING THE PERIOD. LOCAL IFR IN AREAS OF LATE
NIGHT/MORNING FOG.
-- End Changed Discussion --

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH THURSDAY NIGHT/...MODERATE CONFIDENCE.

TONIGHT...S-SW WINDS GUSTING UP TO 25 TO 30 KT EARLY WILL DIMINISH
AS THEY VEER TO W OVERNIGHT AS THE COLD FRONT PASSES. SEAS WILL
REMAIN AOA 5 FT.

THURSDAY...W WINDS WILL NOT BE QUITE AS STRONG ACROSS THE WATERS
AS BEST MIXING WILL OCCUR AWAY FROM THE COAST. WILL SEE GUSTS UP
TO 20 KT...BUT SEAS WILL REMAIN AOA 5 FT.

THURSDAY NIGHT...W WINDS WILL SHIFT TO N-NW AS ANOTHER COLD FRONT
MOVES THROUGH...AND WILL START TO PICK UP LATE WITH GUSTS UP TO 20
KT. SEAS CONTINUE AOA 5 FT.

OUTLOOK...FRIDAY THROUGH MONDAY...

FRIDAY THROUGH MONDAY...WINDS BELOW 25 KNOTS THROUGH THE PERIOD.
SEAS BELOW 5 FEET FRIDAY THROUGH SUNDAY...THEN 5 FOOT SEAS RETURN
TO THE EXPOSED SOUTHERN WATERS ON MONDAY.

&&

.FIRE WEATHER...
THURSDAY...EXPECT MINIMUM RH VALUES IN THE 20 TO 30 PERCENT RANGE.
WILL SEE EXCELLENT MIXING...POSSIBLY FROM 700 TO 750 HPA LEVEL
/AROUND 9KFT/. THIS...ALONG WITH TEMPS SOARING TO THE MID 70S TO
AROUND 80...W-SW WIND GUSTS WILL APPROACH 30-35 KT ESPECIALLY
NEAR AND N OF THE MASS PIKE FROM LATE MORNING THROUGH MID TO LATE
AFTERNOON. THE REGION IS CLOSE TO GREEN UP...EXPECT FOR HIGHER
TERRAIN OF N MA AND ACROSS S NH. AT THIS POINT...WILL CONTINUE TO
MONITOR BUT MAY NEED AT LEAST A SPECIAL WEATHER STATEMENT FOR
ENHANCED FIRE WEATHER CONDITIONS ESPECIALLY ACROSS INLAND AREAS OF
CENTRAL AND WESTERN MASS INTO S NH.

MINIMUM RELATIVE HUMIDITY FRIDAY AND SATURDAY WILL BE 25 TO 40
PERCENT...BUT WITH WINDS BELOW 20 KNOTS.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ231>234-
     251.
     SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ230-
     236.
     SMALL CRAFT ADVISORY UNTIL 5 AM EDT FRIDAY FOR ANZ235-237.
     SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR ANZ250-254>256.

&&

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