Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 201854
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
254 PM EDT MON OCT 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL SLIDE TO THE SOUTH OF THE REGION TODAY KEEPING
THE WEATHER QUIET. A LONG DURATION COASTAL STORM WILL BRING
PERIODS OF RAIN TUESDAY AND WEDNESDAY WITH LINGERING SHOWERS
THURSDAY AND FRIDAY AS THE STORM MOVES OVER NEW ENGLAND AND THEN
SLOWLY PULLS AWAY. DRY AND MILD WEATHER IS EXPECTED NEXT WEEKEND.

&&

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

MOSTLY SUNNY SKIES AT MID AFTERNOON WILL GRADUALLY GIVE WAY TO MORE
MID LEVEL CLOUDINESS THAT WILL WORK IN FROM THE WEST
THROUGH EARLY EVENING.  HIGH TEMPS WILL TOP OUT IN THE MIDDLE TO
UPPER 50S IN MOST LOCATIONS...BUT LESS WIND THAN YESTERDAY WILL MAKE
IT FEEL MUCH MILDER OVER THE NEXT FEW HOURS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
TONIGHT AND TOMORROW...

LOW PRESSURE SYSTEM WILL BEGIN TO DEVELOP ACROSS THE GREAT LAKES
OVERNIGHT. THIS PUTS THE REGION IN MORE OF A SOUTHWEST FLOW AND
BEGIN TO MOISTEN THE COLUMN. ANTICIPATE CLOUDS TO BE ON THE INCREASE
OVERNIGHT LIMITING THE POTENTIAL FOR RADIATIONAL COOLING. THEREFORE
KEPT TEMPS IN THE LOW TO MID 40S...WARMER ALONG THE SOUTH COAST
THANKS TO THE SW FLOW.

SW LLJ WILL BEGIN TO INCREASE CLOSER TO DAYBREAK AND WITHIN THE SW
WAA FLOW...SHOWERS WILL DEVELOP IN THE MORNING HOURS. THE BEST SHOT
WILL BE ACROSS THE CAPE AND ISLANDS AND PERHAPS THE COASTAL
PLAIN...ALIGN WITH THE LOCATION OF THE LLJ. THERE IS A SLIGHT CHANCE
FOR SOME THUNDER OVER THE SOUTHEASTERN WATERS AND EVEN THE CAPE AND
ISLANDS ON TUESDAY WITH CAPE VALUES NEAR 500 J/KG COMBINED WITH
STEEP LAPSE RATES AND LI VALUES BELOW 0. BECAUSE OF THIS AND THE
INCREASING LLJ HAVE INSERTED ISO THUNDER INTO THE FORECAST.

UPPER LEVEL LOW WILL BECOME CUTOFF OVER THE EASTERN GREAT LAKES
DURING THE DAY...AND WILL DOMINATE THE REGION FOR THE REMAINDER OF
THE WEEK. ALTHOUGH THE MAIN SHORTWAVE/LIFT WILL BE AWAY FROM THE
REGION...THERE IS STILL THE POTENTIAL FOR A FEW SHOWERS TO DEVELOP
ACROSS THE WESTERN ZONES. RIGHT NOW HAVE THE HIGHER CONFIDENCE THAT
THE CAPE AND THE ISLANDS WILL SEE THE BEST CHANCE FOR RAINFALL ON
TUESDAY.

BECAUSE OF THE RETURN FLOW AND THAT SOUTHERN NEW ENGLAND IS IN WARM
AIR ADVECTION SIDE OF THE SYSTEM...TEMPS WILL WARM INTO THE UPPER
50S TO MID 60S.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...

BIG PICTURE...

CLOSED UPPER LOW OVER THE MID ATLANTIC COAST WEDNESDAY MIGRATES
ACROSS NEW ENGLAND THURSDAY AND INTO THE MARITIMES FRIDAY. SHORTWAVE
FROM THE PACIFIC NORTHWEST RACES ACROSS THE NORTHERN TIER OF STATES
THIS WEEK AND CROSSES NEW ENGLAND SATURDAY. HIGH PRESSURE RIDGE THEN
BUILDS OVER THE NORTHEAST USA SUNDAY AND MONDAY. HEIGHT CONTOURS ARE
BELOW NORMAL MUCH OF THE WEEK UNDER THE INFLUENCE OF THE UPPER
LOW...THEN RECOVER TO NORMAL LEVELS BY SUNDAY AS THE RIDGE BUILDS.

THIS PATTERN FAVORS A COOL WET MID AND LATE WEEK...THEN DRY AND
SEASONABLE BY SUNDAY AND MONDAY.  MODERATE CONFIDENCE IN THE TYPES
OF WEATHER...BUT LOW CONFIDENCE IN EXACT TIMING.

THE DAILIES...

WEDNESDAY-THURSDAY...COASTAL LOW SURFACE AND ALOFT WILL DOMINATE OUR
WEATHER AS IT MOVES UP THE COAST. LOW PRESSURE TO OUR SOUTH AND AN
EAST 50-60 KNOT LOW LEVEL JET ACROSS COASTAL MAINE AND WRAPPING INTO
NH/VT. THIS MAY BRING ENHANCED ISENTROPIC LIFT ACROSS SOUTHERN NH
AND NORTHERN MASS...WITH WEAKER LIFT FARTHER SOUTH. BY THURSDAY THE
COLD CORE IS DIRECTLY OVERHEAD. SO WEDNESDAY IS A TRANSITION FROM
STRATIFORM TO CONVECTIVE...THURSDAY MAINLY CONVECTIVE. SUFFICIENT
INSTABILITY BOTH DAYS TO INDICATE A CHANCE OF THUNDER.

FRIDAY...LOW PRESSURE SURFACE AND ALOFT WILL MOVE OFF TO THE EAST.
COLD CORE STILL CLOSE ENOUGH TO PROVIDE CLOUDS AND SOME INSTABILITY.
SHOULD CONTINUE TO BE A DIMINISHING CHANCE OF SHOWERS.

SATURDAY...COLD FRONT ASSOCIATED WITH UPPER SHORTWAVE MOVES THROUGH
LATER SATURDAY OR SATURDAY NIGHT. THE APPROACH OF THIS FRONT MAY
ACTUALLY BE THE NUDGE THAT GETS THE LAST OF THE COLD POOL CLOUDS OUT
OF OUR AREA. THE FRONT WILL BRING A PERIOD OF CLOUDS. THE
POTENTIAL FOR SHOWERS IS LESS DEFINED AND SO WE FEATURE JUST SLIGHT
CHANCE POPS IN SRN NH AND NRN MASS. TEMPS ALOFT SUPPORT DAYTIME
MAX TEMPS IN THE 60S.

SUNDAY-MONDAY...HIGH PRESSURE BUILDS OVER THE NORTHEAST WITH TEMPS
ALOFT WARMER FROM SUNDAY TO MONDAY. TEMPS ALOFT SUPPORT 60S BOTH
DAYS.


&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH TUESDAY NIGHT/...

THIS AFTERNOON...HIGH CONFIDENCE IN VFR.

TONIGHT...HIGH CONFIDENCE IN VFR.  SCATTERED SHOWERS MAY DEVELOP
ACROSS EASTERN NEW ENGLAND TOWARD DAYBREAK.

TUESDAY...MODERATE CONFIDENCE.  CONDITIONS PROBABLY DETERIORATE TO
MAINLY MVFR THRESHOLDS...BUT BRIEF IFR CIGS/VSBYS ARE POSSIBLE.
SCATTERED SHOWERS EXPECTED WITH AN ISOLATED THUNDERSTORM OR TWO
POSSIBLE.  BULK OF THE FOCUS ACROSS EASTERN NEW ENGLAND.

TUESDAY NIGHT...MODERATE CONFIDENCE.  LOW END MVFR TO PERHAPS IFR
CONDITIONS DOMINATE IN LOW CLOUDS...SCATTERED SHOWERS AND FOG
PATCHES. THE BULK OF THE ACTIVITY WILL LIKELY BE FOUND ACROSS OUR
NORTHERN ZONES.

KBOS...HIGH CONFIDENCE IN TAF TONIGHT WITH MODERATE CONFIDENCE ON
TUESDAY.  LOW PROBABILITY OF AN ISOLATED THUNDERSTORM ON TUESDAY.

KBDL...HIGH CONFIDENCE IN TAF TONIGHT WITH MODERATE CONFIDENCE ON
TUESDAY.

OUTLOOK...WEDNESDAY THROUGH SATURDAY...MODERATE CONFIDENCE.

WEDNESDAY-THURSDAY...PROLONGED PERIOD OF MIXED MVFR/IFR...WITH MORE
IFR IN RAIN WEDNESDAY AND MORE MVFR IN SHOWERS THURSDAY. CHANCE OF
THUNDER BOTH DAYS. CHANCE OF 30 KNOT EAST-NORTHEAST WIND GUSTS
WEDNESDAY MORNING ALONG THE OUTER CAPE AND MASSACHUSETTS NORTH SHORE
AREAS.

FRIDAY-SATURDAY...VFR. AREAS OF MVFR CIGS/VSBYS IN SHOWERS ON
FRIDAY...WITH THE BEST CHANCE IN SOUTHERN NH AND EASTERN MASS.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /TODAY THROUGH TUESDAY/...HIGH CONFIDENCE.

TODAY...
HIGH PRESSURE BUILDS OVER THE WATERS ALLOWING FOR THE WINDS TO
SLOWLY DIMINISH. WESTERLY WINDS WILL SWITCH TO THE SOUTHWEST BY
THE AFTERNOON. SEAS WILL LINGERING AROUND 5 FEET DURING THE
THE AFTERNOON SO HAVE EXPANDED SCA ACCORDINGLY. WOULD NOT BE
SURPRISED IF IT IS CANCELLED EARLIER.

TONIGHT... HIGH PRESSURE MOVES OFFSHORE. SOUTHWEST WINDS WILL REMAIN
BELOW 25 KTS AND SEAS WILL REMAIN BELOW 5 FEET. LIGHT RAIN MOVES
UP FROM THE MID ATLANTIC COAST LATE AT NIGHT.

TOMORROW...SOUTHWEST FLOW WILL ALLOWING RAIN SHOWERS TO MOVE
ACROSS THE SOUTHEASTERN WATERS. CONDITIONS WILL REMAIN BELOW SCA
BUT THERE IS A LOW PROB FOR AN ISO THUNDERSTORM DURING THE DAY.

OUTLOOK...WEDNESDAY THROUGH SATURDAY...MODERATE CONFIDENCE.

WEDNESDAY-THURSDAY...LOW LEVEL EAST-NORTHEAST JET WILL BE FEEDING
INTO THE MAINE MID-COAST WEDNESDAY. THE POTENTIAL FOR STRONG SURFACE
WINDS SHOULD REMAIN NORTH OF OUR WATERS. WINDS OF 25-30 KNOTS MAY
EXTEND AS FAR SOUTH AS THE MERRIMACK RIVER AND POSSIBLY CAPE ANN.
WINDS DIMINISH AND BECOME VARIABLE THURSDAY AS THE COASTAL LOW MOVES
ACROSS THE WATERS. SEAS WEDNESDAY REACH 5 FEET ON THE OUTER WATERS
WITH 8 TO 10 FEET POSSIBLE FROM CAPE ANN TO MERRIMACK RIVER. BY
THURSDAY THE PERSISTANT NORTHEAST FLOW WILL EXPAND THE AREA OF 8 TO
10 FOOT SEAS ACROSS THE EASTERN WATERS.  SMALL CRAFT ADVISORY WILL
BE NEEDED FOR THE EASTERN WATERS AND SOUTHERN OUTER WATERS.

FRIDAY... AS THE COASTAL LOW PRESSURE MOVES OFF TOWARD THE
MARITIMES...WINDS WILL BECOME NORTHWEST WITH GUSTS AROUND 20 KNOTS.
WITH THE SHIFTING OF THE WIND DIRECTION TO OFFSHORE...WE EXPECT SEAS
TO DIMINISH. BUT 5 FOOT SEAS MAY LINGER ON THE OUTER WATERS THROUGH
THE DAY.

SATURDAY...WINDS AND SEAS SHOULD REMAIN BELOW SMALL CRAFT LEVELS.

&&

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

&&

$$
SYNOPSIS...WTB/DUNTEN
NEAR TERM...FRANK
SHORT TERM...DUNTEN
LONG TERM...WTB
AVIATION...WTB/FRANK
MARINE...WTB/DUNTEN



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