Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 080306
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1106 PM EDT TUE JUL 7 2015

.SYNOPSIS...
WARM AND MUGGY NIGHT THANKS TO A TROPICAL AIRMASS OVER THE
REGION. A COLD FRONT MOVES ACROSS THE AREA WEDNESDAY WILL BRING
SHOWERS AND THUNDERSTORMS...SOME WITH HEAVY DOWNPOURS. LEFTOVER
SHOWERS WILL CONTINUE WEDNESDAY NIGHT AS THE FRONT MOVES SOUTH OF
THE REGION. COOLER TEMPERATURES EXPECTED ON THURSDAY...WITH A
RISK FOR A PERIOD OF SHOWERS MAINLY LATE THURSDAY AND THURSDAY
NIGHT SOUTH OF THE MASSACHUSETTS TURNPIKE. HIGH PRESSURE WILL
THEN BRING DRY AND WARM WEATHER FRIDAY...SATURDAY AND PROBABLY
INTO MUCH OF SUNDAY. A PERIOD OR TWO OF UNSETTLED WEATHER MAY
ARRIVE EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...

1045 PM UPDATE...

AFTER SHOWERS AND THUNDERSTORMS...SEVERAL WITH LOCALLY FLOODING
RAINFALL AS WELL AS ONE WITH A REPORTED MICROBURST LATE THIS
AFTERNOON ACROSS PORTIONS OF NW MA...MOVED FURTHER E AFTER SUNSET
AND DISSIPATED. AT 02Z...A POCKET OF DRIER AIR ALOFT MOVING ACROSS
BUT STILL VERY SOUPY AT THE SURFACE WITH DEWPTS IN THE UPPER 60S
TO LOWER 70S. TEMPS WILL NOT DROP OFF MUCH MORE WITH THE HIGH
DEWPTS IN PLACE.

LEFTOVER LOW CLOUDS AND PATCHY FOG WILL LINGER...ESPECIALLY ALONG
THE S COAST...CAPE COD AND THE ISLANDS. STILL SOME QUESTION AS TO
WHETHER VSBYS WILL DROP BELOW 1 MILE OR EVEN PATCHY DENSE FOG
ALONG THE S COAST WITH TROPICAL AIRMASS IN PLACE BUT WILL MONITOR
CLOSELY.

HAVE UPDATED NEAR TERM GRIDS TO BRING CONDITIONS CURRENT.

PREVIOUS DISCUSSION...
WILL SEE SOME MIXING STILL IN PLACE ALONG THE S COAST...WHICH
COULD LIMIT DENSE FOG POTENTIAL. STILL CANT RULE IT OUT AS WELL
AS LOW STRATUS. LOW CONFIDENCE ON HOW WIDE SPREAD IF/IT WILL GET
SO FOR NOW BELIEVE THAT PATCHY FOG MAY OCCUR.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
***FLASH FLOOD WATCH ISSUED FOR LATE WEDNESDAY MORNING INTO
  WEDNESDAY EVENING FOR ALL OF RHODE ISLAND AND MOST OF SOUTHEAST
  MASSACHUSETTS***

HAVE DECIDED TO HOIST A FLASH FLOOD WATCH FOR ALL OF RHODE ISLAND
AND SOUTHEAST MA LATE WEDNESDAY MORNING INTO WEDNESDAY EVENING.  A
NUMBER OF THINGS HAVE US CONCERNED INCLUDING 2+ INCH PWATS...K INDEX
VALUES AROUND 36...ALONG WITH CAPE VALUES LIKELY TO REACH OR EXCEED
1000 J/KG WITH DAYTIME HEATING.  COMBINED ALL THOSE FACTORS OVER
THE HIGHLY URBANIZED AREAS...FELT IT WAS WORTH A FLASH FLOOD WATCH.
LATER SHIFTS MAY HAVE TO EXPAND IT A BIT FURTHER NORTHWEST
DEPENDING ON WHAT THE LATEST GUIDANCE DEPICTS.

WEDNESDAY...

ANOTHER SHORTWAVE WILL MOVE ACROSS WESTERN NEW ENGLAND TOMORROW.
THIS WILL BRING A COLD FRONT ACROSS THE REGION. THERE IS STILL A
LARGE SPREAD IN GUIDANCE ON TIMING OF THE FRONT WITH THE HI-RES/NAM
FASTER VS THE GFS/EC/RGEM. WENT CONSERVATIVE AND PLAYED DOWN THE
MIDDLE OF THE ROAD FOR TIMING.

SOUTHWEST FLOW CONTINUING INTO THE MORNING HOURS...AND WITH A COLD
FRONT APPROACHING COULD SEE SCT SHOWERS AND THUNDERSTORMS DEVELOP
BY LATE MORNING LASTING INTO THE EVENING HOURS. BIGGEST THREAT
WITH THE STORMS WILL BE HEAVY RAIN LEADING TO LOCALIZED FLOODING.
IN FACT IT APPEARS THAT THE FRONT WILL SLOW DOWN ITS SOUTHWARD
MOVEMENT AND STALL SOMEWHERE ACROSS THE THE SOUTH COAST. WITH THIS
SLOW MOVEMENT AND THE WINDS BEING PARALLEL WITH THE FRONT...COULD
SEE TRAINING CELLS. ALSO APPEARS THAT THERE WILL BE GOOD BL
MOISTURE CONVERGENCE ALONG THE FRONT.CONSIDERED ISSUING A FLASH
FLOOD WATCH FOR TOMORROW AFTER...ESP FOR THE 95 CORRIDOR AND
POINTS SOUTH AND EAST FOR 2+ INCH PWATS...COMBINED WITH TRAINING
CELLS...BUT HAVE A LOW CONFIDENCE. SOMETHING THE NEXT SHIFT MAY
NEED TO THINK ABOUT.

CANNOT RULE OUT A FEW STRONG THUNDERSTORMS TOMORROW...BUT HAVE A LOW
CONFIDENCE AS SHEAR AND LAPSE RATES ARE STILL WEAK. TEMPS ALOFT
BARELY COOL A DEGREE KEEPING THE ATMOSPHERE PRETTY STABLE AND WITH
THE FRONT BEING DISPLACED BY THE SHORTWAVE...REALLY LOSING A GOOD
AMOUNT OF FORCING. STILL WITH 70F DEWPOINTS CANT DISMISS THE
POTENTIAL FOR A QUICK SPIN-UP OR WET MICROBURST.

WEDNESDAY NIGHT...

WEAK COLD FRONT WILL STALL SOMEWHERE ACROSS THE SOUTH SHORE
OVERNIGHT. A MID-LEVEL WAVE WILL RIDE ALONG THE FRONT DEVELOPING A
WEAK LOW PRESSURE SYSTEM. AS THIS SYSTEM MOVES CLOSER...COULD SEE
SCT SHOWERS AND PERHAPS A THUNDERSTORM DEVELOP OVERNIGHT. STORM
MOTION WILL BE MOVING FORM THE SW TO THE NE AND INCREASE IN AREAL
COVERAGE THROUGH THE NIGHT. TEMPS WILL BE COOLER AS FRONTAL PASSAGE
WILL BRING IN LOWER DEWS AND TEMPS. A COMFORTABLE NIGHT AHEAD...BUT
A FEW SCT SHOWERS.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...

* COOLER THU/THU NIGHT BUT UNCERTAIN IF WE SEE A PERIOD OF SHOWERS
* MAINLY DRY AND WARM FRI/SAT AND PROBABLY INTO MUCH OF SUNDAY
* A PERIOD OR TWO OF UNSETTLED WEATHER POSSIBLE EARLY NEXT WEEK

DETAILS...

THURSDAY AND THURSDAY NIGHT...

COOLER AND LESS HUMID WEATHER WILL BE USHERED IN ON THURSDAY BEHIND
A COLD FRONT.  DEPARTING WAVE MAY RESULT IN SOME LEFT OVER MORNING
SHOWERS....ESPECIALLY ACROSS SOUTHEAST NEW ENGLAND.

OTHERWISE...A LOT OF CLOUDS EXPECTED ON THURSDAY.  MAIN UNCERTAINTY
IS IF SOME OF OUR AREA IS AFFECTED BY AN MCS LATE THU INTO THU
NIGHT.  WE WILL BE ON THE COOL SIDE OF THE BOUNDARY WITH BASICALLY
NO SURFACE INSTABILITY.  MANY TIMES THESE MCS/S TEND TO GRAVITATE TO
WHERE THE HIGHEST INSTABILITY RESIDES...WHICH IN THIS CASE WILL BE
TO OUR SOUTHWEST.  SO WOULD NOT BE SURPRISED IF MUCH OF THE AREA
ENDED UP DRY LATE THU/THU NIGHT.  NONETHELESS...A PERIOD OF SHOWERS
IS CERTAINLY POSSIBLE WITH THE BEST CHANCE SOUTH OF THE MA PIKE AND
ESPECIALLY NORTHERN CT.  NOT CONCERNED ABOUT THUNDER OR SEVERE
WEATHER WITH LIMITED INSTABILITY.  HIGH TEMPS ON THU WILL MAINLY BE
IN THE 70S...AND MAY STRUGGLE TO REACH 70 ON THE IMMEDIATE EASTERN
MA COAST.

FRIDAY THROUGH SUNDAY...

NORTHWEST FLOW ALOFT SHOULD PROVIDE DRY WEATHER WITH WARM
AFTERNOON/S.  HIGHS SHOULD REACH INTO THE 80S IN MOST LOCATIONS
FRI/SAT AND SUN AWAY FROM THE COAST.  ITS POSSIBLE THAT A FEW
LOCATIONS FLIRT WITH 90 ON SUNDAY...IF CLOUDS AND ANY SCATTERED
PRECIPITATION WITH AN APPROACHING SHORTWAVE HOLD OFF UNTIL SUN NIGHT
OR MON.

SUNDAY NIGHT THROUGH TUESDAY...

LOW CONFIDENCE FORECAST ESPECIALLY WITH TIMING...BUT A PERIOD OR TWO
OF UNSETTLED WEATHER IS CERTAINLY POSSIBLE.  THE MODELS DO SHOW A
FEW SHORTWAVES DROPPING INTO OUR REGION IN NORTHWEST FLOW ALOFT...SO
THE RISK FOR A PERIOD OR TWO OF SHOWERS WITH SOME EMBEDDED
THUNDERSTORMS EXISTS. TIMING UNCERTAIN...SO WILL CARRY LOW POPS SUN
NIGHT INTO TUE BUT NOT EXPECTING A WASHOUT.  SEASONABLE TEMPS MUCH
OF THE TIME.

&&

.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH WEDNESDAY NIGHT/...

OVERNIGHT...MODERATE CONFIDENCE.
CONDITIONS WILL LOWER TO MVFR TO IFR. MVFR FOG MAY DEVELOP AS
WELL ACROSS THE INTERIOR. COULD SEE IFR VSBYS ACROSS COASTAL
REGION TONIGHT.

WEDNESDAY INTO WEDNESDAY NIGHT...MODERATE CONFIDENCE.
APPROACHING COLD FRONT WILL BRING SCT -SHRA AND -TSRA ACROSS THE
REGION. ANTICIPATE MVFR/IFR CIGS WITHIN ANY -TSRA AS WELL AS VSBY
RESTRICTIONS. OTHERWISE VFR FOR THE DAY. FRONT WILL STALL ACROSS
SOUTH SHORE ALLOWING FOR SHOWERS TO OVERSPREAD TOMORROW NIGHT.
CIGS COULD DROP TO MVFR.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF.

KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.

OUTLOOK...THURSDAY THROUGH SUNDAY...

THURSDAY AND THURSDAY NIGHT...MODERATE TO HIGH CONFIDENCE.  MAINLY
VFR CONDITIONS BUT CAN NO RULE OUT A PERIOD OF MVFR CIGS/VSBYS IN A
CLUSTER OF SHOWERS...HIGHEST RISK SOUTH OF MA PIKE LATE THU INTO THU
NIGHT.

FRIDAY AND SATURDAY...HIGH CONFIDENCE IN MAINLY VFR CONDITIONS.

SUNDAY...MODERATE CONFIDENCE.  MAINLY VFR BUT MAY SEE MVFR-IFR
CONDITIONS DEVELOP ACROSS THE INTERIOR LATE SUN OR SUNDAY
NIGHT...BUT THAT IS HIGHLY UNCERTAIN.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

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

OVERNIGHT...GUSTS UP TO 20 KT ON THE SOUTHERN OUTER WATERS WITH
SEAS UP TO 3-4 FT. ALL SMALL CRAFTS HAVE ENDED AS CONDITIONS HAVE
DIMINISHED. PATCHY FOG DEVELOPS WITH REDUCED VSBYS...BELOW 3
MILES.

WEDNESDAY...SW WINDS WILL INCREASE...WITH GUSTS UP TO 20 KT ON THE
SOUTHERN OUTER WATERS. EXPECT SEAS TO REMAIN BELOW 5 FT...THOUGH
MAY BRIEFLY REACH 5 FT AT TIMES. CHANCE OF SHOWERS/THUNDERSTORMS
SOME WITH HEAVY RAINFALL.

WEDNESDAY NIGHT...FRONT WILL SIT ACROSS THE SOUTH SHORE...WITH A
LOW PRESSURE RIDING ALONG IT COULD SEE INCREASE IN SEAS AND
WINDS. SHOWERS WILL ALSO INCREASE FOR THE SOUTHERN WATERS.

OUTLOOK...THURSDAY THROUGH SUNDAY...

WEAK PRESSURE GRADIENT SHOULD KEEP WINDS/SEAS BELOW SMALL CRAFT
ADVISORY THRESHOLDS THROUGH THE WEEKEND.  OVERALL...NICE BOATING
WEATHER EXPECTED.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...FLASH FLOOD WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
     EVENING FOR MAZ013-015>022.
RI...FLASH FLOOD WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
     EVENING FOR RIZ001>007.
MARINE...NONE.

&&

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



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