Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 021811
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
210 PM EDT MON MAY 2 2016

.SYNOPSIS...
A WARM FRONT WILL STRUGGLE TO MAKE IT NORTH OF THE SOUTH COAST THIS
AFTERNOON BEFORE STALLING OUT TONIGHT. LOW PRESSURE TRAVELS UP ALONG
THE FRONT TUESDAY WHICH WILL BRING ANOTHER PERIOD OF RAIN TO THE
REGION. YET ANOTHER LOW PRESSURE AREA DROPS THROUGH THE GREAT LAKES
WEDNESDAY AND STALLS OVER THE WATERS SOUTH OF NEW ENGLAND FOR
THURSDAY THROUGH SATURDAY BRINGING A CONTINUED THREAT OF SHOWERS
ALTHOUGH THERE WILL BE DRY PERIODS AS WELL. A COLD FRONT WILL MOVE
THROUGH NEXT SUNDAY WITH MORE SHOWERS.

&&

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

205 PM UPDATE...

STEADY RAIN HAS ALREADY MOVED OFF THE EASTERN MA COAST WITH THE
ASSOCIATED SHORTWAVE.  STILL ENOUGH ELEVATED INSTABILITY FOR A BAND
OF SCATTERED SHOWERS TO RE-DEVELOP ACROSS WESTERN MA/NORTHERN CT AT
MID AFTERNOON.  THIS ACTIVITY WILL NOT BE NEARLY AS INTENSE AND MORE
SCATTERED IN NATURE...BUT SHOULD MOVE ACROSS THE REST OF THE REGION
THROUGH LATE AFTERNOON.

LOW CLOUDS/FOG PATCHES WILL KEEP THE WARM FRONT JAMMED NEAR THE
SOUTH COAST AND TEMPS IN THE UPPER 40S TO THE LOWER 50S...EXCEPT
SOME MIDDLE 50S IN PORTIONS OF RI/SOUTHEAST MA.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...

WET PATTERN CONTINUES THROUGH TUESDAY WITH THE FRONT STALLED JUST
SOUTH OF SOUTHERN NEW ENGLAND AND SEVERAL AREAS OF LOW PRESSURE
TRAVELING ALONG IT.  NOT EXPECTING THE ENTIRE PERIOD TO BE
RAINY...BUT PERIODS OF RAIN COUPLED WITH AREAS OF DRIZZLE AND FOG
WILL KEEP THE AREA IN THE GRAY...DAMP...COOL THAT WE OFTEN ASSOCIATE
WITH APRIL RATHER THAN MAY.  THERE IS A LITTLE BIT OF LINGERING
ELEVATED INSTABILITY EARLY TONIGHT...BUT AT MOST EXPECT A FEW
RUMBLES OF THUNDER OVER THE SOUTHERN WATERS. TEMPERATURES WILL BE
RATHER STEADY GIVEN THE MOISTURE WITH LOWS IN THE MID 40S NORTH TO
UPPER 40S SOUTH AND HIGH TEMPERATURES BARELY CLIMBING INTO THE 50S
DURING THE DAY.

&&

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

* UNSETTLED WEATHER WITH PERIODS OF SHOWERS AT TIMES INTO NEXT
  WEEKEND BUT THERE WILL BE DRY PERIODS AS WELL
* MOSTLY BELOW NORMAL TEMPS...BUT MILDER NEXT WEEKEND

OVERVIEW...
MODELS ARE IN GOOD AGREEMENT ON THE OVERALL PATTERN IN THE EXTENDED
PERIOD FEATURING A DEVELOPING OMEGA BLOCK ACROSS THE CENTRAL US WITH
CLOSED LOWS MOVING INTO THE WEST COAST AND DROPPING SOUTH FROM THE
GT LAKES TO THE MID ATLC COAST. STRONG BLOCKING DOWNSTREAM RIDGE
OVER THE ATLANTIC WILL ENSURE THAT THIS PATTERN WILL BE SLOW TO
BREAK DOWN SO WE ARE LOOKING AT AN UNSETTLED PERIOD INTO THE WEEKEND
WITH SHOWERS FROM TIME TO TIME...BUT DRY PERIODS AS WELL. THERE ARE
SIGNS THAT THE CLOSED LOW COULD GET KICKED EAST BY THE END OF THE
WEEKEND AS NORTHERN STREAM VORTEX DROPS S FROM HUDSON
BAY...DELIVERING A COLD FRONTAL PASSAGE. LOW CONFIDENCE ON TEMPS AS
WELL AS TIMING AND DETAILS OF PRECIP WHICH WILL DEPEND ON THE
PLACEMENT OF THE UPPER LOW AND ATTENDING SFC LOW.

DETAILS...

TUE NIGHT...
LOW PRES S OF NEW ENG TUE EVENING WILL BE MOVING OFFSHORE AS SFC
RIDGING BUILDS S INTO NEW ENG. ANY LIGHT RAIN SHOULD BE EXITING THE
REGION IN THE EVENING AND MOST OF THE NIGHT SHOULD BE DRY...BUT CANT
RULE OUT A FEW SHOWERS...ESPECIALLY INTERIOR AS MID LEVEL SHORTWAVE
LIFTS TO THE N OF THE REGION.

WEDNESDAY...
A MID LEVEL SHORTWAVE MOVING THROUGH MID ATLC REGION THEN NE ALONG
THE COAST WILL LIKELY GENERATE ANOTHER SFC WAVE S OF NEW ENG. WEAK
WARM ADVECTION COMBINED WITH DEEPENING MOISTURE WILL LIKELY LEAD TO
MORE SHOWERS DEVELOPING IN THE AFTERNOON...WITH BEST FOCUS ACROSS
THE INTERIOR UNDER THE RIGHT ENTRANCE REGION OF THE UPPER JET. LOW
CONFIDENCE TEMP FORECAST GIVEN WIDE RANGE IN MODEL GUIDANCE WITH
ECMWF IN THE 40S...GFS 50S AND NAM 60S. LOW LEVEL NE FLOW AND
DAMMING SIGNATURE WILL RESULT IN BELOW NORMAL TEMPS BUT LOW
CONFIDENCE ON HOW COOL. WE WILL LEAN TOWARD GFS WITH HIGHS IN
THE 50S WHICH IS A COMPROMISE...BUT POTENTIAL FOR COOLER EXITS.

THURSDAY THROUGH SUNDAY...
UNSETTLED CONDITIONS EXPECTED AT TIMES DURING THIS PERIOD BUT LOW
CONFIDENCE ON TIMING...DURATION AND EXTENT OF SHOWER ACTIVITY.
CLOSED LOW OVER THE OHIO VALLEY WILL GRADUALLY MOVE OFF THE MID ATLC
COAST...BUT EXACT LOCATION SOUTH OF NEW ENG IS UNCERTAIN AND THIS
WILL IMPACT SENSIBLE WEATHER. WHILE IT MAY BE WET AT TIMES THERE
WILL BE PERIODS OF DRY WEATHER AS WELL. IT DOES APPEAR COLD FRONT
WILL BE MOVING THROUGH ON SUNDAY WHICH WILL KICK LOW PRES OUT TO SEA
BUT BRING A PERIOD OF SHOWERS. FORECAST CONFIDENCE ON TEMPS IS ALSO
LOW AND WILL DEPEND ON EXTENT OF CLOUD COVER AND WHETHER THERE IS
ANY BREAKS OF SUN. TEMPS WOULD LIKELY REACH WELL INTO THE 60S IN THE
INTERIOR WITH ANY SUN...BUT COOLER ALONG THE COAST WITH PERSISTENT
E/NE FLOW. MILDEST DAY MAY BE SUN AS WINDS TURN SW AHEAD OF
APPROACHING FRONT WITH 70+ DEGREE READINGS POSSIBLE AWAY FROM THE
COAST.

&&

.AVIATION /18Z 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 AFTERNOON/...

THROUGH LATE AFTERNOON...MODERATE TO HIGH CONFIDENCE.  STEADY/HEAVY
RAIN HAS ALREADY MOVED OFF THE EASTERN MA COAST AT MID AFTERNOON AND
JUST EXPECTED SCATTERED SHOWERS THE REST OF THE AFTERNOON.  IFR
CONDITIONS WILL DOMINATE.

TONIGHT...MODERATE CONFIDENCE.  SOME LOCATIONS MAY IMPROVE TO LOW
END MVFR.  IFR TO LIFR CONDITIONS LIKELY PERSIST ACROSS THE
SOUTHEAST NEW ENGLAND COAST IN LOW CLOUDS AND FOG. DRY WEATHER THIS
EVENING OTHER THAN A SPOT SHOWER...BUT BAND OF RAIN SHOWERS WILL
MOVE INTO AREAS ALONG AND SOUTH OF MA TURNPIKE FROM WEST TO EAST
BETWEEN 6 AND 12Z. SOME SHOWERS MAY REACH NEAR THE NH BORDER...BUT
CONFIDENCE IS LOWER FURTHER NORTH.

TUESDAY...MODERATE TO HIGH CONFIDENCE.  BULK OF SHOWERS MOVES EAST
OF THE REGION TUE MORNING.  OTHERWISE...MAINLY DRY WEATHER FOR THE
REST OF TUE BUT MVFR-IFR CIGS/VSBYS PERSIST WITH THE LOWER
CONDITIONS LIKELY ON THE COAST.  SOME GRADUAL IMPROVEMENT IS
EXPECTED INLAND FROM THE COAST.

KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.  IFR CONDITIONS MAY
BRIEFLY IMPROVE TO MVFR AFTER 00Z THIS EVENING IF WINDS CAN
TEMPORARILY SHIFT TO THE NORTHWEST. IF SO...IFR CONDITIONS PROBABLY
RE-DEVELOP AFTER 10Z WITH A BAND OF RAIN SHOWERS.

KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.  IFR CONDITIONS PROBABLY
IMPROVE TO LOW END MVFR THIS EVENING.

OUTLOOK /TUESDAY NIGHT THROUGH FRIDAY/...MODERATE CONFIDENCE

TUE NIGHT AND WEDNESDAY...AREAS OF MVFR/IFR CIGS WITH A FEW
SHOWERS AT TIMES.

THURSDAY AND FRIDAY...AREAS OF MVFR/IFR WITH SCT SHOWERS.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

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

SMALL CRAFT ADVISORIES FOR SEAS CONTINUE THROUGH TONIGHT FOR THE
OUTER WATERS.  SEAS WILL BE AROUND 5 FEET ON THESE WATERS.
OTHERWISE...WINDS AND SEAS REMAIN BELOW CRITERIA AND MAIN ISSUE WILL
BE PERIODS OF RAIN AND FOG LIMITING VISIBILITIES.  THIS AFTERNOON
AND EVENING...THERE MAY BE A FEW RUMBLES OF THUNDER ON THE SOUTHERN
WATERS.

OUTLOOK /TUESDAY NIGHT THROUGH FRIDAY/...MODERATE CONFIDENCE

SURFACE FLOW IS MOSTLY EAST TO NORTHEAST THROUGH THE PERIOD WITH
SPEEDS BELOW SCA. SEAS WILL LIKELY APPROACH 5 FT OVER THE OUTER
WATERS FROM SWELL GENERATED BY THE PERSISTENT EASTERLY FLOW. VSBYS
MAY BE REDUCED AT TIMES IN SHOWERS AND FOG.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 AM EDT TUESDAY
     FOR ANZ250-254-255.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM EDT THIS
     EVENING FOR ANZ256.

&&

$$
SYNOPSIS...KJC/RLG
NEAR TERM...FRANK
SHORT TERM...RLG
LONG TERM...KJC
AVIATION...FRANK/KJC
MARINE...KJC/RLG


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