Area Forecast Discussion
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FXUS61 KBOX 192039
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
439 PM EDT SUN APR 19 2015

.SYNOPSIS...
A WIND SWEPT SOAKING RAIN IS EXPECTED MONDAY AND MONDAY NIGHT...WITH
EVEN A FEW THUNDERSTORMS POSSIBLE AT NIGHT. SCATTERED SHOWERS AND
MILD TEMPS TUESDAY MORNING GIVE WAY TO A DRYING TREND DURING THE
AFTERNOON. THEN MUCH COOLER WEATHER OVERSPREADS THE AREA MID TO
LATE NEXT WEEK ALONG WITH THE RISK OF SCATTERED
SHOWERS...ESPECIALLY DURING THE AFTERNOON AND EVENING.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
4 PM UPDATE...

A WIDE RANGE IN TEMPS AGAIN LATE THIS AFTERNOON...ALTHOUGH NOT
NEARLY AS EXTREME AS YESTERDAY.  LATE AFTERNOON READINGS RANGED FROM
THE UPPER 40S TO LOWER 50S ALONG THE IMMEDIATE COAST AND LOWER 60S
IN THE CT RIVER VALLEY.  TEMP RANGE WILL BEGIN TO NARROW AFTER
SUNSET...AS THE DRY AIR IN PLACE ALLOWS THE INTERIOR TO BEGIN TO
RADIATE OUT.

HIGH PRESSURE NEAR THE CANADIAN MARITIMES WILL VERY SLOWLY SHIFT
EAST TONIGHT...AS LOW PRESSURE APPROACHES FROM THE MIDWEST. WHILE IT
WILL REMAIN DRY TONIGHT...MID/HIGH LEVEL CLOUDINESS WILL INCREASE
FROM THE WEST AND THICKEN AFTER MIDNIGHT.  LOW TEMPS WILL BOTTOM OUT
MAINLY IN THE UPPER 30S AND LOWER 40S.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
MONDAY...

A WAVE OF LOW PRESSURE APPROACHES FROM THE WEST WITH HIGH PRESSURE
RETREATING ACROSS THE EASTERN CANADIAN MARITIMES.  THIS WILL
GENERATE A CHILLY EAST WIND AT THE SURFACE WITH A SOUTHERLY LOW
LEVEL JET JUST OFF THE DECK.  THE RESULT WILL BE WIDESPREAD RAIN
WHICH WILL WORK ACROSS THE REGION FROM WEST TO EAST. THE RAIN SHOULD
ARRIVE ACROSS WESTERN MA/NORTHERN CT BETWEEN 7 AND 10 AM...REACHING
EASTERN MA/RI BETWEEN 10 AM AND 1 PM. THE RAIN WILL INITIALLY BE
LIGHT...BUT SHOULD PICKUP IN INTENSITY FROM WEST TO EAST DURING THE
MID TO LATE AFTERNOON HOURS...BECOMING MODERATE TO HEAVY AT TIMES.

IT WILL BE UNSEASONABLY CHILLY WITH TEMPS MAINLY IN THE 40S TO NEAR
50 MONDAY AFTERNOON.  IN ADDITION...INCREASING PRESSURE GRADIENT
WILL RESULT IN EASTERLY WIND GUSTS OF 25 TO 35 MPH ALONG THE COAST.
THIS WILL RESULT IN WIND CHILL VALUES IN THE MIDDLE 30S TO THE LOWER
40S!

MONDAY NIGHT...

WAVE OF LOW PRESSURE WILL LIFT NORTHEAST AND MOVE NEAR OR NORTHWEST
OF THE I-95 CORRIDOR.  THIS SHOULD ALLOW RHODE ISLAND AND AT LEAST
SOUTHEAST MA TO WARM SECTOR...ALLOWING TEMPS TO RISE INTO THE 50S.
LOW LEVEL JET OF 50 KNOTS COMBINED WITH PWATS OF 1 TO 1.5 INCHES
WILL ALLOW FOR NUMEROUS SHOWERS...ESPECIALLY DURING THE FIRST PART
OF THE NIGHT.  IN ADDITION...SHOWALTER INDICES DROPPING BELOW ZERO
MAY RESULT IN A FEW ELEVATED THUNDERSTORMS.  THE HIGHEST RISK OF ANY
CONVECTION WILL BE ACROSS RHODE ISLAND/SOUTHEAST MA ON THE NOSE OF
THE LOW LEVEL JET...BUT ITS POSSIBLE ACROSS THE ENTIRE REGION.

GIVEN RELATIVELY HIGH PWATS AND GOOD FORCING...BRIEF HEAVY RAIN MAY
RESULT IN TYPICAL NUISANCE POOR DRAINAGE STREET FLOODING.
HOWEVER...NO SIGNIFICANT FLOODING PROBLEMS ARE EXPECTED AS WE ARE
ONLY LOOKING AT BETWEEN 1 AND 2 INCHES OF TOTAL RAINFALL.  THE ONE
AREA WE MAY HAVE TO WATCH IS ACROSS EASTERN CT/RI/SOUTHEAST MA.  A
FEW OF OUR MESOSCALE MODELS ARE INDICATING THE POTENTIAL FOR 2+
INCHES OF RAIN WITH PERHAPS SOME CONVECTION.  AGAIN THOUGH...THIS
REALLY LOOKS LIKE TYPICAL BRIEF NUISANCE POOR DRAINAGE STREET
FLOODING EVENT.

&&

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

* TUE...SCATTERED MORNING SHOWERS THEN AN AFTERNOON DRYING TREND
* WED-SAT...COOLER WITH PERIODS OF SHOWERS...MAINLY DIURNAL

SYNOPTIC OVERVIEW AND MODEL PREFERENCES...

AMPLIFYING NORTHERN STREAM PHASES WITH SOUTHERN PLAINS CUTOFF LOW
TODAY TO FORM AN ANOMALOUS LOW/VORTEX OVER THE GREAT LAKES TUE.
THEREAFTER THIS UPPER LOW WILL BE VERY SLOW TO MOVE AS HIGH LATITUDE
BLOCKING DEVELOPS WITH POSITIVE HEIGHT ANOMALY EVOLVING OVER THE
SOUTHERN DAVIS STRAIT. THIS RESULTS IN A VERY SLOW MOVING VORTEX
FROM THE NORTHERN GREAT LAKES WED TO ONLY ADVANCING EASTWARD INTO
MAINE BY NEXT WEEKEND! WHILE THIS SEEMS EXTREME IT/S DOES HAVE
SUPPORT FROM TELECONNECTIONS AS AO/NAO AND EPO AS ALL THREE INDICES
GO NEGATIVE. GIVEN GOOD MODEL AGREEMENT A BLEND OF OPERATIONAL
GUIDANCE WILL WORK BEST AS A BASELINE FOR THIS PORTION OF THE
FORECAST.

DAILY DETAILS...

TUESDAY...TRAILING SHORT WAVE TROUGH AND ATTENDING COLD FRONT ALONG
WITH TRIPLE POINT LOW WILL BE MOVING ACROSS THE AREA DURING THE
MORNING. THIS WILL LIKELY YIELD A ROUND OF SHOWERS TO THE REGION.
INSTABILITY ALOFT MAY BE SUFFICIENT FOR ELEVATED THUNDER. IF NOT AT
THE VERY LEAST THIS INSTABILITY WILL ENHANCE SHOWER INTENSITY AND
ASSOCIATED DOWNPOURS. BY AFTERNOON DRY SLOT WILL BE WORKING ITS WAY
AROUND THE SYSTEM AND INTO THE REGION. SO SUSPECT WITH DEEPENING DRY
LAYER AND COLD ADVECTION TUE AFTERNOON WILL FEATURE A DRYING TREND
FROM SOUTH TO NORTH. IN ADDITION...MILD START TO THE DAY COMBINED
WITH BREAKS OF AFTERNOON SUNSHINE POSSIBLE AND WEAK COLD AIR
ADVECTION HIGHS WILL WARM INTO THE 60S.

WED AND THU...WHILE BOTH ENSEMBLES AND DETERMINISTIC GUIDANCE ARE IN
VERY GOOD AGREEMENT ON THE TIMING AND TRACK OF MID LEVEL CLOSED
LOW...AS EXPECTED MODELS ARE STRUGGLING WITH THE AMPLITUDE AND
TIMING OF INDIVIDUAL SHORT WAVES CIRCULATE AROUND THE VORTEX. THUS
LOW CONFIDENCE ON TIMING SHOWER THREAT THIS PERIOD. TRENDING COOLER
AS MID LEVEL LOW AND ASSOCIATED COLD POOL ALOFT ADVECT EASTWARD INTO
THE REGION. COOLER THU THAN WED.

FRIDAY AND SATURDAY...ECENS/EPS SUGGEST CORE OF COLD AIR ALOFT
SETTLES OVER THE AREA AS MID LEVEL LOW TRACKS ACROSS NORTHERN NY
STATE AND NORTHERN NEW ENGLAND WITH 850 TEMPS COOLING TO -2C TO
-5C! RISK OF SHOWERS TOO GIVEN COLD AIR AND CYCLONIC FLOW ALOFT. NOT
OUT OF THE QUESTION THAT SCATTERED RAIN SHOWERS MIX WITH SOME SNOW
AT TIMES ACROSS THE HIGHER TERRAIN!

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...

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

.SHORT-TERM /THIS AFTERNOON THROUGH MONDAY NIGHT/...

TONIGHT...HIGH CONFIDENCE IN VFR CONDITIONS DESPITE INCREASING MID
LEVEL CLOUDINESS.

MONDAY...MODERATE TO HIGH CONFIDENCE.  CONDITIONS DETERIORATE TO
MVFR FROM WEST TO EAST MONDAY MORNING INTO MID AFTERNOON IN
WIDESPREAD RAIN.  IFR CONDITIONS MAY DEVELOP BY MID TO LATE
AFTERNOON FROM WEST TO EAST...AS HEAVIER RAIN WORKS INTO THE REGION.
THIS IN RESPONSE TO WIDESPREAD RAIN WORKING IN FROM THE WEST.
EASTERLY WINDS WILL ALSO GUST TO 30 KNOTS ALONG THE COAST BY
AFTERNOON.

MONDAY NIGHT...MODERATE TO HIGH CONFIDENCE.  MAINLY LOW END MVFR TO
IFR CONDITIONS. PERIODS OF SHOWERS CONTINUE MONDAY NIGHT AS AT LEAST
THE SOUTHERN HALF OF THE REGION PROBABLY ENTERS THE WARM SECTOR.  A
FEW EMBEDDED THUNDERSTORMS ARE ALSO POSSIBLE...WITH THE HIGHEST RISK
ON THE SOUTH COAST NEAR THE NOSE OF THE LOW LEVEL JET BUT THEY ARE
POSSIBLE ACROSS THE ENTIRE REGION.  WHILE SOUTHEAST WINDS MAY GUST
TO 30 KNOTS ALONG THE COAST...LLWS OF 50 TO 60 KNOTS EXPECTED AT
2000 THOUSAND FEET WITH DEVELOPING LOW LEVEL JET.

KBOS TAF...HIGH CONFIDENCE THROUGH 14Z MONDAY IN VFR CONDITIONS.
MVFR CONDITIONS IN SOME RAIN ARE EXPECTED TO REACH THE TERMINAL
BETWEEN 15Z AND 18Z.

KBDL TAF...HIGH CONFIDENCE THROUGH 11 OR 12Z MONDAY IN VFR
CONDITIONS. MVFR CONDITIONS IN SOME RAIN ARE EXPECTED TO REACH THE
TERMINAL BETWEEN 12Z AND 14Z.

OUTLOOK...TUESDAY THROUGH FRIDAY...

TUE INTO EARLY WED...HIGH CONFIDENCE.
CONDITIONS IMPROVE TO VFR EARLY TUE. ALTHOUGH LINGERING CLOUDS
AND SHOWERS ARE POSSIBLE. THE VFR CONDITIONS CONTINUE INTO EARLY
WED W WINDS ON TUE GIVE WAY TO SW WINDS ON WED...WITH A FEW GUSTS
TO AROUND 20 KT POSSIBLE.

WED EVENING INTO EARLY THU...MODERATE CONFIDENCE.
COLD FRONT INCREASES THE RISK FOR MORE WIDESPREAD SHOWERS.
CONDITIONS MAY DIP TO MVFR/IFR AT TIMES DURING THE OVERNIGHT
HOURS.

REST OF THU AND FRI...HIGH CONFIDENCE.
MAINLY VFR.  CHANCE FOR AFTERNOON/EVENING SHOWERS.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH MONDAY NIGHT/...

TONIGHT...HIGH CONFIDENCE WINDS/SEAS REMAIN BELOW SCA THRESHOLDS
THROUGH AT LEAST 8 OR 9Z WITH RELATIVELY WEAK PRESSURE GRADIENT IN
PLACE.

MONDAY AND MONDAY NIGHT...MODERATE TO HIGH CONFIDENCE.  HIGH
PRESSURE OVER THE CANADIAN MARITIMES AND AN APPROACHING LOW PRESSURE
SYSTEM FROM THE WEST WILL RESULT IN AN INCREASING PRESSURE GRADIENT.
PERSISTENT EAST TO SOUTHEAST WIND GUSTS OF 25 TO 35 KNOTS DEVELOP BY
MONDAY AFTERNOON AND CONTINUE INTO MONDAY EVENING.  WE HOISTED GALES
FOR OUR EASTERN OUTER-WATERS WITH BETTER MIXING EXPECTED AND HAVE
STRONG SCA POSTED ELSEWHERE.  HOWEVER...BRIEF SOUTHEAST GALE FORCE
WIND GUSTS CAN NOT BE RULED OUT ANYWHERE MONDAY NIGHT ESPECIALLY IF
WE CAN GENERATE ANY CONVECTION.

SEAS WILL BUILD TO BETWEEN 10 AND 15 FEET WITH LONG EASTERLY FETCH
ACROSS OUR EASTERN WATERS.  SHOWERS...A FEW THUNDERSTORMS AND PATCHY
FOG WILL ALL CONTRIBUTE TO REDUCED VISIBILITIES FOR MARINERS AT
TIMES.

OUTLOOK...TUESDAY THROUGH FRIDAY...

TUE AND WED...HIGH CONFIDENCE.
ALTHOUGH W-SW WINDS WILL BE DIMINISHING DURING THE DAY ON
TUE...LINGERING LARGE SWELL OF 10+ FT ON THE OCEAN WATERS
EXPECTED. THIS SWELL REMAINS ABOVE THE 5 FT THRESHOLD ON WED AS
WELL. THEREFORE...SMALL CRAFT ADVISORIES ARE LIKELY TO CONTINUES.

THU AND FRI...
WINDS SHIFT BACK TO THE SW ON THU AHEAD OF A COLD FRONT...WITH THE
POSSIBILITY OF MAINTAINING SWELLS ON S WATERS. WINDS BACK TO THE W
BY FRI. COULD SEE PERIOD GUSTS TO AROUND 25 KT EACH AFTERNOON...SO
WITH THE LEFTOVER SEAS AND PERIODIC GUSTS...SOME SMALL CRAFT
ADVISORIES MAY BE NEEDED AT TIMES.

&&

.TIDES/COASTAL FLOODING...
VERY HIGH ASTRONOMICAL TIDES OCCUR LATE THIS EVENING AND JUST AFTER
MIDNIGHT.  WHILE WE CAN NOT RULE OUT SOME VERY MINOR SPLASH
OVER...DID NOT THINK IT WAS WORTH ANY HEADLINES.  LATER SHIFTS WILL
HAVE TO MONITOR CLOSELY.

EAST TO SOUTHEAST WINDS WILL INCREASE MONDAY INTO MONDAY EVENING.
CURRENT GUIDANCE SUGGESTS THE STRONGEST WINDS OCCUR MONDAY AFTERNOON
AND EARLY EVENING AND NOT COINCIDE WITH THE HIGHEST ASTRONOMICAL
TIDE.  HOWEVER...THE HIGH TIDE WERE CONCERNED ABOUT OCCURS LATE
MONDAY EVENING ALONG THE SOUTH COAST AND VERY EARLY TUE MORNING
ALONG THE EASTERN MA COAST.  WE PROBABLY ARE LOOKING AT A 1 TO 1.5
FOOT STORM SURGE ALONG WITH 10 TO 15 FOOT SEAS OFFSHORE.  THIS
SHOULD BE ENOUGH TO GENERATE POCKETS OF MINOR COASTAL FLOODING AND
SPLASH OVER.  THEREFORE...DECIDED TO HOIST A COASTAL FLOOD ADVISORY
FOR THESE LOCATIONS DURING THEIR LATE MONDAY EVENING AND EARLY TUE
MORNING HIGH TIDES.  WINDS DO NOT LOOK STRONG ENOUGH AT THE TIME OF
HIGH TIDE FOR A MODERATE COASTAL FLOOD EVENT.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...COASTAL FLOOD ADVISORY FROM MIDNIGHT MONDAY NIGHT TO 4 AM EDT
     TUESDAY FOR MAZ007-015-016-019-022-024.
     COASTAL FLOOD ADVISORY FROM 8 PM MONDAY TO MIDNIGHT EDT MONDAY
     NIGHT FOR MAZ020-021.
RI...COASTAL FLOOD ADVISORY FROM 8 PM MONDAY TO MIDNIGHT EDT MONDAY
     NIGHT FOR RIZ002-004>007.
MARINE...SMALL CRAFT ADVISORY FROM 5 AM MONDAY TO 8 AM EDT TUESDAY FOR
     ANZ231>235-237.
     SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 4 AM EDT TUESDAY FOR
     ANZ230-236.
     GALE WARNING FROM NOON MONDAY TO MIDNIGHT EDT MONDAY NIGHT FOR
     ANZ250-251-254.
     SMALL CRAFT ADVISORY FROM 2 AM MONDAY TO 8 AM EDT TUESDAY FOR
     ANZ255-256.

&&

$$
SYNOPSIS...FRANK/DOODY
NEAR TERM...FRANK
SHORT TERM...FRANK
LONG TERM...DOODY
AVIATION...FRANK/DOODY
MARINE...FRANK/DOODY
TIDES/COASTAL FLOODING...STAFF



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