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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBOX 160551
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
151 AM EDT THU MAY 16 2013

.SYNOPSIS...

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.

&&

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

-- Changed Discussion --
2 AM UPDATE...

NUISANCE PATCHY DENSE FOG THIS EVENING WHICH HAS BEEN DIFFICULT TO
NAIL DOWN. DRIER AIR IS SETTLING ACROSS UPSTATE NY BUT IS DELAYED
FROM GETTING OVER AND ACROSS THE BERKSHIRES. COLD FRONT IS
CURRENTLY SWEEPING ACROSS THE REGION AND WINDS ARE TURNING MORE
WESTERLY. ANTICIPATING DRIER AIR TO FILTER IN TOWARDS MORNING.
HIGHER ELEVATIONS ARE LIKELY TO REMAIN CLEAR...BUT INTERIOR
SHELTERED VALLEYS WILL REMAIN FOGGY. FOG WILL ALSO BE AN ISSUE
ALONG THE SHORES WHERE MOISTURE IS MORE ABUNDANT.

TEMPERATURES AND DEWPOINTS REMAINING ON TRACK. NO OTHER CHANGES
MADE TO THE FORECAST.

WITH ANY DENSE FOG...EXPECT REDUCED VISIBILITIES THAT WILL MAKING
DRIVING HAZARDOUS. MOTORISTS SHOULD BE AWARE OF THIS THREAT AND
EXERCISE CAUTION BY TAKING IT SLOW WHERE APPROPRIATE.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...

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.

&&

.LONG TERM /FRIDAY NIGHT 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 /06Z THURSDAY THROUGH MONDAY/...

-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS...

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

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

6Z UPDATE...

FOG HAS BEEN A NUISANCE WITH MVFR-VLIFR VARIABILITY. HAVE GREATER
CONFIDENCE THAT SHELTERED VALLEY TERMINALS WITH CALM WINDS...AND
TERMINALS ALONG THE S/SE SHORES...WILL SEE FOG INTO SUNRISE.

THEREAFTER VFR WITH WESTERLY WIND GUSTS AROUND 30 KTS THROUGH THE
DAY. SECONDARY DRY COLD FRONT WILL SHIFT WINDS OUT OF THE N/NW
THURSDAY NIGHT...MOSTLY CLEAR WITH LESSER CONFIDENCE OF FOG
IMPACTS. N/NW WINDS WITH POTENTIAL GUSTS AROUND 20 KTS CONTINUING
INTO FRIDAY BUT DIMINISHING INTO THE EVENING. VFR.

KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.

KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.

OUTLOOK...SATURDAY 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...

-- Changed Discussion --
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
     ANZ231>234-251.
     SMALL CRAFT ADVISORY UNTIL 5 AM EDT FRIDAY FOR ANZ235-237.
     SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR ANZ250-254>256.
-- End Changed Discussion --

&&

$$

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