Area Forecast Discussion
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000
FXUS61 KBOX 042322
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
722 PM EDT WED MAY 4 2016

.SYNOPSIS...
CLOUDY...DREARY AND COOL WEATHER CONTINUES THROUGH FRIDAY WITH
PERIODS OF RAIN AS WEAK WAVES OF LOW PRESSURE PASS SOUTH AND EAST OF
OUR REGION. SOME SHOWERS ARE STILL POSSIBLE AT TIMES THIS
WEEKEND...BUT TEMPERATURES WILL BEGIN TO MODERATE. SIGNIFICANT
IMPROVEMENT WILL LIKELY OCCUR EARLY TO MIDDLE OF NEXT WEEK AS HIGH
PRESSURE BUILDS IN WITH MUCH MILDER TEMPERATURES.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
***A PERIOD OF STEADY RAIN IN MOST LOCATIONS THIS EVENING WILL TAPER
TO SCATTERED SHOWERS/AREAS OF DRIZZLE AFTER MIDNIGHT***

7 PM UPDATE...
BAND OF STEADY MODERATE RAINFALL CONTINUES MAINLY SE OF A LINE
FROM HFD-ORH-BVY ALONG A TRACK OF HIGHER PWATS AND MODEST ELEVATED
INSTABILITY AHEAD OF DEVELOPING LOW PRES OFFSHORE. ALREADY SEEING
BREAKS ACROSS NY/NJ WHICH WILL MOVE NE THROUGH THE
EVENING...BRINGING THE WIDESPREAD RAINFALL TO AN END BETWEEN
04Z-06Z THIS EVENING. HRRR/WRF POPS WERE USED WITH THIS UPDATE.

OCCASIONAL EMBEDDED TS AND HEAVIER RAIN STILL EXPECTED WITH
INDIVIDUAL CELLS ABLE TO OVERACHIEVE AMONGST THE ELEVATED
INSTABILITY.

PREVIOUS DISCUSSION...

CLOSED UPPER LEVEL LOW DROPPING SOUTH TOWARDS THE OHIO VALLEY WAS
BACKING THE MID LEVEL FLOW.  THIS WAS ALLOWING FOR A DEEPER PLUME OF
MOISTURE TO ADVECT NORTHWARD INTO SOUTHERN NEW ENGLAND.  AT THE SAME
TIME...ANOTHER WAVE OF LOW PRESSURE WAS APPROACHING SOUTHERN NEW
ENGLAND.  THE RESULT WILL BE A PERIOD OF STEADY RAIN ACROSS MOST OF
SOUTHERN NEW ENGLAND THIS EVENING...SOME OF WHICH MAY BE BRIEFLY
HEAVY.  THERE ALSO IS SOME MARGINAL ELEVATED INSTABILITY...SO A FEW
EMBEDDED THUNDERSTORMS CAN NOT BE RULED OUT.  THE HIGHEST RISK FOR
THAT ACROSS SOUTHEAST NEW ENGLAND.

THE SHORTWAVE LIFTS NORTHEAST OF THE REGION LATER THIS
EVENING...TAKING THE STRONGER FORCING WITH IT.  HOWEVER...AN
ABUNDANCE OF LOW LEVEL MOISTURE REMAINING ALONG WITH NORTHEAST FLOW
WILL RESULT IN SCATTERED SHOWERS...AREAS OF DRIZZLE AND PATCHY FOG
PERSISTING. LOW TEMPS WILL BOTTOM OUT IN THE 40S.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
***UNSEASONABLY COOL/DREARY WEATHER CONTINUES THURSDAY/THURSDAY
NIGHT WITH A PERIOD OF STEADY RAIN LIKELY LATE IN THE AFTERNOON AND
EVENING ACROSS EASTERN NEW ENGLAND***

THURSDAY AND THURSDAY NIGHT...

ANOTHER WAVE OF LOW PRESSURE WILL BE TRACKING SOUTHEAST OF SOUTHERN
NEW ENGLAND THURSDAY INTO THURSDAY EVENING.  THIS COMBINED WITH HIGH
PRESSURE OVER THE CANADIAN MARITIMES WILL RESULT IN ANOTHER
DREARY/UNSEASONABLY COOL DAY ACROSS THE REGION.  THIS NEXT WAVE OF
LOW PRESSURE WILL BE A BIT STRONGER THAN THE PAST FEW...SO NORTHEAST
WIND GUSTS OF 20 TO 30 MPH ARE EXPECTED ACROSS THE EASTERN HALF OF
SOUTHERN NEW ENGLAND WITH PERHAPS A FEW GUSTS TO 35 MPH.  HIGH TEMPS
ON THURSDAY WILL ONLY BE IN THE UPPER 40S TO AROUND 50 IN MOST
LOCATIONS.  GUSTY WINDS ALONG THE COASTAL PLAIN WILL RESULT IN WIND
CHILLS IN THE UPPER 30S TO THE LOWER 40S IN THIS REGION!

AS FOR PRECIPITATION...GIVEN MOIST ONSHORE FLOW...LOW CLOUDS ALONG
WITH SCATTERED SHOWERS/AREAS OF DRIZZLE AND PATCHY FOG ARE EXPECTED
THU INTO THU NIGHT.  A PERIOD OF STEADIER RAINFALL WILL PROBABLY
OCCUR LATE THURSDAY AFTERNOON AND EVENING ACROSS EASTERN NEW
ENGLAND. THIS WILL DEPEND ON EXACTLY HOW CLOSE INTENSIFYING LOW
PRESSURE AND ITS ASSOCIATED DEEPER MOISTURE/FORCING TRACK IN REGARDS
TO THE SOUTHERN NEW ENGLAND COAST.  ECMWF/NAM ARE THE MOST ROBUST
SHOWING 40 TO 50 KNOTS OF NORTHEAST WINDS AT 925 MB...WHILE THE GFS
IS WEAKER. EITHER WAY...GIVEN THAT TYPE OF NORTHEAST LOW LEVEL FLOW
THERE SHOULD BE A PERIOD OF STEADIER RAIN AT LEAST ALONG THE EASTERN
MA COAST.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
*/ HIGHLIGHTS...

 - THRU THE WEEKEND AN UNSETTLED COOL PATTERN OF LOW CLOUDS/DRIZZLE
 - TWO BOUTS OF MORE APPRECIABLE WET WEATHER: FRIDAY AND SUNDAY
 - MODERATE WARMING DRY TREND THRU NEXT WEEK
 - NEXT SHOT OF UNSETTLED WEATHER POSSIBLE AT THE FOLLOWING FRIDAY

OVERVIEW AND MODEL PREFERENCES...
VERY AMPLIFIED TROF-RIDGE-TROF PATTERN CONTINUES ACROSS THE CONUS
WITH HIGHLY POSITIVE PNA...BUT NEAR NEUTRAL NAO/AO/EPO. LITTLE
CHANGE IS EXPECTED IN THIS PATTERN FRI AND SAT...HOWEVER BY SUN AN
ARCTIC VORTEX FORMING NEAR HUDSON BAY WILL ACT AS A KICKER
FORCING THE STAGNANT TROF ACROSS THE NORTHEAST TO FINAL SHIFT E.
THIS BREAKS DOWN THE CENTRAL RIDGE AND ALLOWS PHASING WITH THE SRN
STREAM. THE RESULT IS YET ANOTHER TROF EARLY NEXT WEEK ACROSS THE
NE...BUT NOT AS DEEP AS THE FEATURE THAT INFLUENCED OUR WX
THROUGH THIS WEEK. BLEND OF DETERMINISTIC GUIDANCE STILL SEEMS
REASONABLE WITH THIS UPDATE...AS IT FEATURES THE TWO PRIMARY
PERIODS OF RAINFALL EXPECTED THROUGH SUN..AND THEN A DRYING TREND
THEREAFTER.

DETAILS...

FRI AND SAT...
THE FINAL VORT MAX ASSOCIATED WITH THE STUBBORN CUTOFF LOW PRES
WHICH HAS DEFINED OUR WX OF LATE WILL BE ROTATING ACROSS NEW
ENGLAND FROM S-N LATE FRI INTO EARLY SAT. PWATS ARE NEAR
NORMAL...WITH MUCH OF THE COLUMNS MOISTURE TRAPPED IN THE LOWEST
300MB...THEREFORE...EXPECT THIS TO BE MAINLY A BATCH OF WIDESPREAD
SHRA/DRIZZLE WETTING THE GROUNDS ONCE AGAIN. FINAL TOTALS STILL
REMAIN GENERALLY AT OR BELOW A QUARTER INCH. DRIER...BUT COOL
CONDITIONS FOLLOW FOR THE AFTERNOON SAT. TEMPS REMAIN GENERALLY
BELOW NORMAL UNDER MOSTLY CLOUDY SKIES AND LITTLE CHANGE IN
AIRMASS. RAW MODEL 2M TEMPS ARE BETTER SUITED HERE...BUT STILL
LIKELY A BIT TOO HIGH.

SUN...
ARCTIC VORTEX AND ATTENDANT SFC COLD FRONT SWEEP ACROSS NEW
ENGLAND WITH A RENEWED RISK FOR WIDESPREAD SHRA AS THE FRONT MOVES
THROUGH. NOTING A SLIGHT INCREASE IN PWATS IN THE RETURN FLOW
AHEAD OF THIS FEATURE COMBINED WITH A CONDITIONALLY UNSTABLE LAYER
BETWEEN H9 AND H7 WHICH COULD SUPPORT A FEW HEAVIER SHRA. WHILE
FINAL QPF VALUES ARE EXPECTED TO REACH ONLY ABOUT 0.25 INCHES...IT
WILL FALL OVER A SHORTER PERIOD OF TIME SUN AFTERNOON. COOLER AND
DRIER TEMPERATURES FOLLOW THE FROPA...WITH CLEARING EXPECTED INTO
THE OVERNIGHT HOURS.

MON...
REINFORCING ARCTIC FRONT MOVES THROUGH EARLY MON...BUT MAIN
IMPACTS WILL BE INCREASED NW FLOW AND A SLIGHT COOL DOWN IN TEMPS.
OVERALL COLUMN MOISTURE IS MUCH LOWER BY THE TIME OF THIS
FROPA...SO LITTLE IF ANY PRECIPITATION IMPACTS ARE EXPECTED. IN
SPITE OF THE SUN BREAKING THROUGH CLOUDS THROUGH THE DAY. HIGHS
MAY ONCE AGAIN STRUGGLE TO REACH SEASONAL NORMALS AS H85 TEMPS
AVERAGE ONLY ABOUT +3C. THIS WOULD YIELD HIGHS MAINLY IN THE UPPER
50S AND LOW 60S.

TUE AND WED...
SOME UNCERTAINTY IN WHERE WEAK BAROCLINIC ZONE WILL SET UP BUT AT
THIS TIME...IT APPEARS IT WILL HOLD NEAR OR SLIGHTLY S OF THE
REGION. THIS SUGGESTS THE PATTERN FOR MAINLY NEAR OR SLIGHTLY
BELOW NORMAL WX TO CONTINUE INTO THE MIDDLE OF NEXT WEEK. MODELS
ARE ALSO DRY THROUGH THE COLUMN FOR THE MOST PART...SUGGESTING
THAT HIGH PRES WILL YIELD A LULL IN PRECIP ACTIVITY CONTINUING
INTO AT LEAST WED.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH THURSDAY NIGHT/...MODERATE TO HIGH CONFIDENCE.

TONIGHT...NO MAJOR CHANGES WITH THE 00Z UPDATE. WIDESPREAD VFR
FROM HFD-ORH-BVY AND POINTS E...WITH MVFR ELSEWHERE. EXPECT
GRADUAL REDUCTION TO IFR WITH SOME EMBEDDED LIFR THROUGH ABOUT
04Z. AREA OF RAIN CONTINUES ACROSS THE SAME LINE AND POINTS E WITH
LOWER VSBYS...ENDING BETWEEN 04Z AND 06Z...THEN TRANSITIONING TO
WIDESPREAD DZ AND FG...MAINTAINING THE LOW CATEGORIES. BREEZY WITH
NE WINDS 15-25 KT AT TIMES.

THURSDAY AND THURSDAY NIGHT...IFR TO LOW END MVFR CONDITIONS
EXPECTED TO CONTINUE IN SCATTERED SHOWERS/LOW CLOUDS AND AREAS OF
DRIZZLE/FOG PATCHES.  A PERIOD OF STEADY RAIN WILL LIKELY OCCUR LATE
THU AFTERNOON/EVENING MAINLY ACROSS EASTERN NEW ENGLAND.  NE WIND
GUSTS OF 20 TO 30 KNOTS ARE EXPECTED ALONG THE COASTAL PLAIN THU
INTO EARLY THU EVENING BEFORE DIMINISHING.

KBOS TERMINAL...MODERATE TO HIGH CONFIDENCE IN TAF.  MVFR CONDITIONS
SHOULD DETERIORATE TO IFR THRESHOLDS SOMETIME THIS EVENING.

KBDL TERMINAL...MODERATE TO HIGH CONFIDENCE IN TAF.  MVFR
CONDITIONS SHOULD DETERIORATE TO IFR THRESHOLDS SOMETIME TONIGHT.

OUTLOOK /FRIDAY THROUGH MONDAY/...

FRI AND SAT...MODERATE CONFIDENCE.
CONTINUED BKN-OVC CONDITIONS WITH OCCASIONAL SHOWERS AND DRIZZLE.
THIS SUGGESTS PERIODS OF MVFR/IFR INTERMIXED WITH EVEN A FEW LOW
VFR PERIODS THROUGH THE TWO DAY STRETCH.

SUN...MODERATE CONFIDENCE.
COLD FRONT SWEEPS THROUGH WITH VFR FIRST GIVING AWAY TO BRIEF
MVFR WITH SHRA...THEN RAPID IMPROVEMENT BACK TO VFR IN THE
AFTERNOON/EVENING.

MON...MODERATE CONFIDENCE.
MAINLY VFR.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

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

A COUPLE WAVES OF LOW PRESSURE COMBINED WITH A HIGH OVER THE
CANADIAN MARITIMES WILL RESULT IN PERSISTENT NORTHEAST WIND GUSTS OF
20 TO 30 KNOTS THROUGH THURSDAY EVENING...BEFORE GRADUALLY
DIMINISHING.  THE STRONGEST OF THOSE WINDS ARE EXPECTED LATE
THURSDAY MORNING INTO THE AFTERNOON...WHERE THERE IS A LOW RISK FOR
A FEW LOCATIONS TO BRIEFLY TOUCH 35 KNOTS.  SCA HEADLINES ARE POSTED
FOR ALL WATERS. OTHER CONCERNS FOR MARINERS WILL BE A FEW EMBEDDED
THUNDERSTORMS THIS EVENING...MAINLY ACROSS OUR SOUTHERN WATERS.
PATCHY FOG MAY ALSO AFFECT THE REGION AT TIMES THROUGH THURSDAY
NIGHT.

OUTLOOK /FRIDAY THROUGH MONDAY/...

GRAY CONDITIONS WITH OCCASIONAL SHOWERS AND DRIZZLE WILL CONTINUE
INTO SUN. THROUGH THIS PERIOD EVEN AS WINDS SHIFT FROM THE E...THE
N-NE AND THEN FINALLY S BY SAT NIGHT INTO SUN...GUSTS SHOULD
REMAIN GENERALLY BELOW 25 KT. HOWEVER...A LINGERING SWELL WILL
PERSIST...ESPECIALLY ACROSS THE OCEAN WATERS...NEAR 5-6 FT.
THEREFORE...SMALL CRAFT CONDITIONS MAY CONTINUE DUE TO THESE SEAS
RIGHT INTO SUN.

MON...CONDITIONS IMPROVE WITH MORE PEAKS OF SUN AND NW FLOW. WIND
GUSTS MAY REACH 25 KT AT TIMES.

&&

.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES OCCUR LATE THURSDAY EVENING THROUGH THE
WEEKEND.

FORTUNATELY...SEAS/WINDS WILL BE BELOW THRESHOLDS FOR A SIGNIFICANT
COASTAL FLOOD EVENT.  HOWEVER...THE POTENTIAL FOR POCKETS OF MINOR
SPLASH OVER/MINOR COASTAL FLOODING EXIST ALONG THE EASTERN MA COAST
DURING THE LATE THURSDAY EVENING AND LATE FRIDAY EVENING HIGH TIDES.

THE ASTRONOMICAL HIGH TIDE LATE THURSDAY EVENING IS 12.0 FEET AT
BOSTON AND THE LATE FRIDAY EVENING IS 12.3 FEET.  THE WINDS WILL BE
A BIT STRONGER THURSDAY EVENING...ESPECIALLY A FEW HOURS BEFORE
ASTRO HIGH TIDE...BUT THE LATE FRIDAY EVENING HIGH TIDE IS A TAD
HIGHER.  ALL IN ALL...POCKETS OF SPLASH OVER/MINOR COASTAL FLOODING
ARE A DECENT POSSIBILITY IN THE TYPICALLY VULNERABLE AREAS.  A
COASTAL FLOOD ADVISORY MAY EVENTUALLY BE NEEDED FOR BOTH THESE HIGH
TIDE CYCLES.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT THURSDAY NIGHT FOR
     ANZ232>234.
     SMALL CRAFT ADVISORY FROM 6 AM TO 7 PM EDT THURSDAY FOR ANZ230-
     236.
     SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT THURSDAY NIGHT FOR
     ANZ231.
     SMALL CRAFT ADVISORY UNTIL 8 PM EDT FRIDAY FOR ANZ235-237-
     254>256.
     SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR ANZ250-251.

&&

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


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