Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 250541
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
141 AM EDT MON MAY 25 2015

.SYNOPSIS...
A WARM FRONT WILL MOVE ACROSS THE REGION MONDAY FOLLOWED BY WARM
AND HUMID CONDITIONS WHICH WILL LIKELY LAST INTO NEXT WEEKEND.
THE THREAT FOR SCATTERED SHOWERS AND THUNDERSTORMS WILL INCREASE
FROM WEDNESDAY AFTERNOON INTO THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
140 AM UPDATE... HIGH CLOUDINESS CONTINUE TO MOVE ACROSS SOUTHERN
NEW ENGLAND OVERNIGHT AHEAD OF A WARM FRONT THAT WAS PROGRESSING
NORTHEASTWARD ACROSS THE APPALACHIANS. TEMPERATURES RANGED FROM
THE MID 50S TO MID 60S ACROSS THE REGION AS OF 140 AM WITH
SOUTHWEST WINDS 5 TO 15 MPH. LIGHT PATCHY FOG IS POSSIBLE MAINLY
ALONG THE SOUTH COAST TOWARD DAYBREAK.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
MONDAY AND MONDAY NIGHT...
BERMUDA HIGH SETS UP ALONG EASTERN SEABOARD. WARM FRONT DEVELOPS
AS IT SHIFTS E ACROSS NY STATE DURING MONDAY. HOWEVER...WITH
STRONG SUBSIDENCE IN PLACE AS WELL AS CONTINUED SW SURFACE WINDS
AND H5 RIDGING BUILDING ACROSS WESTERN NEW ENGLAND...BETTER
MOISTURE AND LIFT WILL REMAIN N AND W OF THE REGION. WHILE THERE
WILL BE NO PRECIP WITH THIS FRONT...WILL SEE A LOT OF CLOUDINESS
STREAMING ACROSS THE REGION. EXPECT THE WARM FRONT TO PUSH NE
ACROSS NORTHERN NEW ENGLAND MON NIGHT.

MAY SEE SOME LEFTOVER PATCHY FOG ALONG THE S COAST EARLY MON
MORNING...THEN AGAIN NEAR THE S COAST AS WELL AS OUTER CAPE COD
AND THE ISLANDS LATE MON NIGHT AS DEWPTS/RH VALUES INCREASE.

EVEN WITH THE CLOUDS...IT WILL STILL BE WARM ON MON WITH HIGHS
AROUND 80 EXCEPT IN THE UPPER 60S AND 70S ACROSS S COASTAL AREAS.
READINGS WILL ONLY FALL BACK TO THE UPPER 50S TO LOWER 60S MON
NIGHT...AND IT WILL BE MUGGY AS DEWPTS CONTINUE TO RISE THROUGH
THE 50S.

&&

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

* WARM AND HUMID INTO THE WEEKEND
* INCREASING SHOWER/THUNDERSTORM POTENTIAL WED INTO THU
* MORE SHOWERS AND THUNDERSTORMS POSSIBLE THIS WEEKEND

OVERVIEW...
MID LEVEL RIDGING ALONG THE EAST COAST WILL BE THE DOMINANT
FEATURE THROUGH MUCH OF THE WEEK...ALTHOUGH NORTHERN STREAM ENERGY
RIDING OVER THE TOP WILL DEAMPLIFY THE RIDGE ALLOWING FOR A WEAK
FROPA AROUND THU TIMEFRAME. ABOVE NORMAL TEMPS WITH INCREASING
HUMIDITY WILL BE THE THEME THROUGH THE WEEK WITH THE WARMEST TEMPS
TUE/WED...WITH POTENTIAL FOR NEAR 90 DEGREES INTERIOR VALLEYS.
BEST CHANCE FOR SHOWERS/TSTMS WILL BE THU WITH THE FROPA...BUT
NEARBY INSTABILITY AXIS SUGGESTS POTENTIAL FOR SCT CONVECTION FOR
INTERIOR LOCATIONS ON WED/FRI. LOOKING AHEAD TO THE WEEKEND...A
MORE ROBUST MID LEVEL TROF WILL BE SLIDING EAST ACROSS SE CANADA
BUT MODELS DIFFER ON TIMING WHICH WILL AFFECT TIMING OF A COLD
FRONT AND SENSIBLE WEATHER. WE LEANED TOWARD WPC GUIDANCE WHICH IS
CLOSER TO SLOWER ECMWF.

TUESDAY INTO WEDNESDAY...
SNE IN THE WARM SECTOR AIRMASS WITH SW FLOW BRINGING WARM AND
INCREASINGLY HUMID CONDITIONS. 850 MB TEMPS 15-16C SUGGEST
POTENTIAL FOR NEAR 90 DEGREES IN SOME OF THE INTERIOR
VALLEYS...BUT SW WINDS OFF COOLER OCEAN WILL KEEP TEMPS IN THE 70S
NEAR THE SOUTH COAST. DEWPOINTS CLIMBING TO 60+ SO IT WILL START
TO FEEL A BIT HUMID COMPARED TO RECENT DAYS.

REGARDING TSTM POTENTIAL...THINK TUE WILL BE MOSTLY DRY WITH
POSSIBLE EXCEPTION OF FAR W NEW ENG AS MODELS GENERATE SOME
MARGINAL INSTABILITY DURING THE AFTERNOON WITH SBCAPES AROUND 500
J/KG AND KI CLIMBING TO 30+. CANT RULE OUT AN ISOLD TSTM ACROSS W
ZONES DURING THE AFTERNOON/EVENING...OTHERWISE MAINLY DRY TUE.
MORE INSTABILITY IS FORECAST ON WEDNESDAY WITH CAPES EXCEEDING
1000 J/KG SO EXPECT SCT AFTERNOON SHOWERS/TSTMS
DEVELOPING...MAINLY CONFINED TO W ZONES WHERE BEST INSTABILITY.
0-6KM SHEAR IS WEAK...LESS THAN 25 KT SO MAIN THREAT IS LOCALLY
HEAVY RAINFALL GIVEN HIGH PWATS.

THURSDAY AND FRIDAY...
NOT MUCH CHANGE IN AIRMASS WITH CONTINUED THREAT OF
SHOWERS/TSTMS...MAINLY INTERIOR. IT APPEARS BEST CHANCE OF
CONVECTION WILL BE THU AS SHORTWAVE PASSES TO THE NORTH WITH
SUBTLE MID LEVEL COOLING AND WEAK FROPA MOVING INTO THE REGION.
CAPES 1000+ J/KG AND SOME CONVERGENCE SUGGESTS A MORE ACTIVE DAY
AND 0-6KM SHEAR IS A BIT STRONGER AS WELL BUT STILL LESS THAN 30
KT. HEAVY RAIN IS MAIN THREAT BUT A FEW STRONG TO SEVERE STORMS
POSSIBLE THU. TEMPS ABOVE NORMAL...WARMEST 80S IN THE INTERIOR.

SATURDAY AND SUNDAY...
GFS IS CONSIDERABLY FASTER THAN ECMWF WITH COLD FRONT WITH
SHOWERS/TSTMS SAT THEN DRYING OUT SUNDAY AS HIGH PRES BUILDS TO
THE N. ECMWF HAS FRONT MOVING THROUGH SUN AFTERNOON/EVENING WITH
BEST CHANCE OF CONVECTION DURING THIS TIME. WPC CONSENSUS FAVORED
LOWER SOLUTION. A LOW CONFIDENCE FORECAST AT THIS TIME RANGE AND
TIMING OF FRONT WILL DICTATE WHICH WEEKEND DAY HAS BETTER CHANCE
OF CONVECTION.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH MONDAY NIGHT/...HIGH CONFIDENCE.

OVERNIGHT...VFR. CIGS 10KFT OR ABOVE OVERNIGHT. MAY SEE PATCHY
FOG WITH MVFR TO LOCAL IFR VSBYS ACROSS THE ISLANDS...POSSIBLY UP
TO THE IMMEDIATE S COAST.

MONDAY AND MONDAY NIGHT...VFR. MAY SEE PATCHY FOG WITH MVFR VSBYS
EARLY MON MORNING AND AGAIN AFTER MIDNIGHT MON NIGHT...MAINLY NEAR
THE S COAST AND OUTER CAPE COD/NANTUCKET. SW WINDS INCREASE MON
NIGHT...GUSTING TO 20-25 KT.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF.

KBDL TERMINAL...HIGH CONFIDENCE IN TAF.

OUTLOOK...TUESDAY THROUGH FRIDAY...MODERATE CONFIDENCE.

MOSTLY VFR CIGS. BUT BRIEF MVFR/IFR IN ANY SHOWERS/THUNDERSTORMS WED
THROUGH FRIDAY. LOW CONFIDENCE ON DURATION AND AREAL EXTENT OF ANY
IFR STRATUS AND FOG DURING THE LATE NIGHT AND MORNING PERIODS. SW
GUSTS TO 25 KT ALONG SE NEW ENG COAST TUE/WED.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH MONDAY NIGHT/...HIGH CONFIDENCE.

OVERNIGHT...SOUTHWEST WINDS 10 TO 20 KT ACROSS THE COASTAL WATERS.
MAY SEE PATCHY FOG DEVELOP LATE TONIGHT ACROSS PORTIONS OF THE
SOUTHERN WATERS WITH LOCALLY REDUCED VSBYS.

MONDAY-MONDAY NIGHT...SW WINDS CONTINUE...GUSTING UP TO 20 KT
DURING MON. SEAS SHOULD REMAIN BELOW 5 FT DURING THE DAY. EXPECT
SW WIND GUSTS TO PICK UP TO 20-25 KT MON NIGHT. SEAS ALSO BUILD
TO 5-6 FT ON THE SOUTHERN WATERS AS WELL AS THE EASTERN OUTER
WATERS.

OUTLOOK...TUESDAY THROUGH FRIDAY...MODERATE CONFIDENCE.

PERSISTENT SW FLOW WITH GUSTS AROUND 20-25 KTS AT TIMES. STRONGEST
WINDS OVER THE NEARSHORE WATERS. INCREASING SWELL AND WIND WAVE
WILL RESULT IN SEAS BUILDING TO 5-6 FT OVER S COASTAL WATERS. FOG
ANTICIPATED DURING THE OVERNIGHT AND MORNING LENDING TO VISIBILITY
RESTRICTIONS.

&&

.FIRE WEATHER...
4 PM UPDATE...
EXPECT DEWPTS TO SLOWLY BUT STEADILY RISE OVERNIGHT AND MONDAY
WITH PERSISTENT SW WINDS IN PLACE. FORECASTED MINIMUM RH VALUES
WILL BE FROM 35 TO 60 PERCENT ON MONDAY...LOWEST ACROSS INTERIOR
AREAS. WITH THE INCREASING HUMIDITY...EXPECT LOWERED FIRE WEATHER
RISK SO WILL NOT BE ISSUING A STATEMENT AT THIS TIME.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.

&&

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



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