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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBOX 131757
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
157 PM EDT MON MAY 13 2013

.SYNOPSIS...
COOL BUT MOSTLY DRY WEATHER IS EXPECTED INTO TUESDAY AS HIGH
PRESSURE REGAINS CONTROL. TEMPERATURES RECOVER TO NEAR TO EVEN
ABOVE NORMAL LEVELS AT TIMES BY THE MIDDLE AND END OF THE WEEK. A
FEW ROUNDS OF SHOWERS ARE ALSO POSSIBLE FOR THE SECOND HALF OF THE
WEEK...BUT A WASHOUT IS NOT EXPECTED.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
145 PM UPDATE...
AREA OF CLOUDS REMAINS ACROSS CENTRAL AND WESTERN AREAS HOLDING
TEMPS IN THE UPPER 40S TO LOWER 50S...WHILE TEMPS HAVE RISEN TO
THE MID-UPPER 50S ACROSS NE CT/RI/SE MA WHERE SKIES ARE MAINLY
CLEAR AT 17Z. SW WINDS HAVE PICKED UP ALONG THE S COAST...WHICH
HAS BROUGHT DEWPTS UP A BIT HIGHER THAN PREVIOUS THINKING SO HAVE
UPDATED GRIDS FOR THIS TREND. NOTING SOME GUSTS UP TO 20-25 KT
EARLIER BUT HAVE SETTLED DOWN A BIT.

AREA OF SHOWERS HAS GROWN ACROSS CENTRAL NY STATE INTO N CENTRAL
PA...BUT NOTING ONLY TRACE AMOUNTS OF PRECIP REPORTED AT SOME
LOCATIONS ACROSS NORTHERN AND W CENTRAL NY AT 17Z. SOME EASTWARD
PROGRESS NEAR AND AHEAD OF THE APPROACHING UPPER LEVEL SHORT
WAVE...SO DOES BEAR WATCHING FOR ANY SPRINKLES THAT MAY MAKE IT
INTO THE CT VALLEY BY AROUND 21Z OR SO.

HAVE UPDATED GRIDS TO BRING CONDITIONS CURRENT AND INCORPORATED
INTO NEAR TERM TRENDS.

PREVIOUS DISCUSSION...
MID LEVEL TROF AMPLIFIES OVER THE MID ATLC REGION LATE TODAY AS
SHORTWAVE ENERGY DIVES SE FROM THE GT LAKES. 500 MB TEMPS COOLING
TO -25 TO -28C BY 00Z. HOWEVER...THE COLUMN IS RATHER DRY WITH
JUST SOME SHALLOW LOW LEVEL MOISTURE WHICH WILL LEAD TO SCT TO
BKN CU...BUT EXPECT DRY WEATHER. IT WILL BE A CHILLY DAY WITH 850
MB TEMPS HOVERING AROUND -2C. MAXES WILL BE MOSTLY IN THE 50S WITH
SOME LOWER 60S IN THE COASTAL PLAIN. STILL ENOUGH LOW LEVEL WIND
TO SUPPORT WEST WIND GUSTS TO 20-25 MPH.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
TONIGHT...
STRONG SHORTWAVE TRACKS S OF NEW ENG TONIGHT WITH OFFSHORE LOW
REMAINING WELL SE OF NEW ENG AS HIGH PRES RIDGE BUILDS TO THE
WEST OF NEW ENG. SOME CLOUD COVER POSSIBLE ACROSS FAR SE NEW
ENG...OTHERWISE EXPECT MOCLEAR SKIES WITH LIGHT WINDS ESPECIALLY
INTERIOR. THIS WILL SET THE STAGE FOR A COLD NIGHT WITH GOOD
RADIATIONAL COOLING CONDITIONS. EXPECT MIN TEMPS IN THE LOW TO MID
30S FOR MOST LOCATIONS WITH SOME UPPER20S FAR NW ZONES. WE ISSUED
A FROST ADVISORY FOR MOST OF THE REGION WHERE GROWING SEASON IS
ACTIVE EXCEPT BOS METRO AREA...E COASTAL MA...NARRAGANSETT BAY
COMMUNITIES AND CAPE/ISLANDS WHERE TEMPS WILL LIKELY REMAIN ABOVE
40. NO HEADLINES FOR NW MA AND SW NH AS GROWING SEASON HERE HAS
NOT OFFICIALLY BEGUN.

TUESDAY...
MID LEVEL TROF MOVES TO THE EAST AS HIGH PRES BUILDS S OF NEW
ENG. ANOTHER DRY DAY WITH SOME CU DEVELOPMENT AS SHALLOW LOW
LEVEL MOISTURE REMAINS IN PLACE...BUT DRY WEATHER CONTINUES. 850
MB TEMPS MODERATE TO AROUND 0C SO EXPECT TEMPS TO BE A FEW DEGREES
MILDER THAN TODAY...GENERALLY UPPER 50S TO MID 60S. LESS PRESSURE
GRADIENT WILL RESULT IN LIGHTER WINDS WHICH WILL PROMOTE
AFTERNOON SEABREEZES NEAR THE COAST.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
GOOD AGREEMENT IN THE MODELS ON SYNOPTIC SCALE FEATURES
THROUGHOUT MUCH OF THE FORECAST PERIOD. THERE ARE SOME TIMING
DIFFERENCES ON FEATURES GOING INTO THE WEEKEND BUT OTHERWISE THE
MODELS AGREE ON THE PATTERN. HIGH PRESSURE WILL MOVE OFFSHORE
WEDNESDAY ALLOWING FOR SHOWERS AHEAD OF A COLD FRONT THAT WILL
MOVE THROUGH THE AREA LATE WEDNESDAY OR THURSDAY. A SECONDARY
FRONT MOVES THROUGH THURSDAY OR FRIDAY DEPENDING ON MODEL
SOLUTION RESULTING IN A VERY UNSETTLED WEATHER PATTERN GOING INTO
THE WEEKEND. HIGH PRESSURE BUILDS INTO SOUTHERN NEW ENGLAND OVER
THE WEEKEND. HOW QUICKLY DEPENDS ON THE TIMING OF THE LOW PRESSURE
MOVING INTO THE MARITIMES AND THE NEXT LOW MOVING INTO THE GREAT
LAKES. GENERALLY WENT WITH A BLEND OF GUIDANCE FOR THE FORECAST.

TUESDAY NIGHT THROUGH THURSDAY...HIGH PRESSURE IS IN CONTROL
TUESDAY NIGHT AND MUCH OF WEDNESDAY. THEN LOW PRESSURE STARTS TO
MOVE E INTO THE JAMES BAY AREA AND SWINGS A COLD FRONT THROUGH
SOUTHERN NEW ENGLAND. THE NAM/GFS ARE A BIT QUICKER WITH THIS
TRANSITION...SWINGING THE COLD FRONT THROUGH WEDNESDAY NIGHT WHILE
THE ECMWF WAITS TIL THURSDAY TO MOVE THE COLD FRONT THROUGH.
EXPECT SHOWERS WEDNESDAY AHEAD OF THIS SYSTEM. COLD TEMPERATURES
TUESDAY NIGHT WILL GIVE WAY TO A WARMING TREND THROUGH THURSDAY OR
FRIDAY...DEPENDING ON THE TIMING OF THE INITIAL FRONT.

FRIDAY THROUGH SUNDAY...TIMING ISSUES ARE THE LARGEST DIFFERENCES
IN THE MODELS. THE SYNOPTIC PATTERN IS GENERALLY THE SAME...THE
GFS IS A BIT FASTER WITH A SECONDARY COLD FRONT THAT WILL MOVE
THROUGH SOUTHERN NEW ENGLAND. FRIDAY LOOKS TO BE MOSTLY DRY WITH
THE FRONT EITHER MOVING THROUGH SOUTHERN NEW ENGLAND THURSDAY
(GFS) OR EARLY FRIDAY (ECMWF). TEMPERATURES WILL BE A BIT COOLER
BUT STILL RIGHT AROUND NORMAL FOR THE WEEKEND. THERE IS THE
POSSIBILITY OF SOME SHOWERS SATURDAY AND SUNDAY WITH A LOW
PRESSURE SYSTEM THAT MAY AFFECT THE AREA.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS...

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

OVERVIEW...HIGH CONFIDENCE IN VFR CONDITIONS THROUGH TUESDAY
NIGHT.

W-SW WIND GUSTS TO 20-25 KT THROUGH LATE AFTERNOON...THEN WILL
DIMINISH. W-NW WINDS MAY PICK UP AGAIN ACROSS CAPE COD AND THE
ISLANDS AFTER 06Z. COASTAL SEA BREEZES LIKELY TUESDAY AFTERNOON.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF.

KBDL TERMINAL...HIGH CONFIDENCE IN TAF.

OUTLOOK...WEDNESDAY THROUGH FRIDAY...

WEDNESDAY THROUGH THURSDAY...MODERATE CONFIDENCE. MAINLY VFR.
COULD SEE MVFR/IFR CONDITIONS IN SHOWERS WEDNESDAY.

FRIDAY...MODERATE CONFIDENCE. VFR.
-- End Changed Discussion --

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

1055 AM UPDATE...
S-SW SWELLS UP TO 7 FT AT BUOY 44097 SE OF BLOCK ISLAND AT 14Z SO
UPDATED THOSE TO BRING CURRENT. REMAINDER OF FORECAST LOOKS ON
TRACK BUT DID UPDATE TO BRING CONDITIONS CURRENT.

FORECAST CONFIDENCE IS HIGH THROUGH TUESDAY.

ANOTHER ROUND OF WESTERLY WIND GUSTS TO 20-25 KT IS EXPECTED
TODAY...BUT WINDS SHOULD BEGIN TO DIMINISH BY MID AFTERNOON. WINDS
AND SEAS BELOW SCA THRESHOLDS TONIGHT AND TUE. LEFTOVER SWELL WILL
KEEP SEAS AT 5-6 FT OVER THE SOUTH COASTAL OPEN WATERS TODAY THEN
SUBSIDING TONIGHT INTO TUE. CONTINUED CURRENT SMALL CRAFT
ADVISORIES AND EXPANDED THE SCA TO THE NEARSHORE WATERS TODAY FOR
A PERIOD OF G25 KT.

OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...

MODERATE CONFIDENCE. SEAS BUILD THROUGH THURSDAY AND ARE BACK
OVER 5 FEET WEDNESDAY NIGHT INTO THURSDAY AS A COLD FRONT
APPROACHES THE WATERS. SEAS START TO DIMINISH FRIDAY AS HIGH
PRESSURE MOVES OVER THE WATERS BRIEFLY. WINDS WILL APPROACH SMALL
CRAFT CRITERIA WEDNESDAY NIGHT INTO THURSDAY AS THE COLD FRONT
APPROACHES AND THEN CROSSES THE WATERS.

&&

.FIRE WEATHER...
ALTHOUGH SOME AREAS IN SE MA RECEIVED 1+ INCHES OF RAINFALL
SAT INTO SUN MORNING...MOST OF THE REGION HAD LESS THAN A HALF
INCH SO RAINFALL DEFICITS CONTINUE FOR THE MONTH OF MAY.

CONDITIONS EARLY THIS WEEK WILL BE CONDUCIVE FOR ELEVATED FIRE
WEATHER. TODAY...MIN RH VALUES ARE EXPECTED TO DIP INTO THE
20S...WITH W WINDS GUSTING TO 25 MPH. TUESDAY...MIN RH VALUES ARE
IN THE 20S AGAIN BUT WINDS WILL BE LIGHTER...WITH GUSTS ONLY 10-15
MPH AT BEST. HOWEVER...BY WEDNESDAY STRONGER S TO SW WINDS COULD
APPROACH 20-30 MPH AT TIMES AGAIN WITH MIN RH VALUES NEAR 30
PERCENT.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FROST ADVISORY FROM 2 AM TO 8 AM EDT TUESDAY FOR CTZ002>004.
MA...FROST ADVISORY FROM 2 AM TO 8 AM EDT TUESDAY FOR MAZ005-006-
     012-013-017-018-020-021-026.
     FREEZE WARNING FROM 2 AM TO 8 AM EDT TUESDAY FOR MAZ009>011.
NH...NONE.
RI...FROST ADVISORY FROM 2 AM TO 8 AM EDT TUESDAY FOR RIZ001-003-
     006.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
     ANZ230>234-236-250-251.
     SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ235-
     237-254>256.

&&

$$
SYNOPSIS...KJC/RLG
NEAR TERM...KJC/RLG/EVT
SHORT TERM...KJC
LONG TERM...RLG
AVIATION...RLG/EVT
MARINE...KJC/RLG/EVT
FIRE WEATHER...STAFF