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Area Forecast Discussion
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000
FXUS61 KBOX 280045
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
845 PM EDT SUN JUL 27 2014

.SYNOPSIS...
A RATHER STRONG AREA OF LOW PRESSURE BY JULY STANDARDS WILL DEVELOP 
OVER NY AND PA TONIGHT. ITS WARM FRONT WILL BRING A ROUND OF HEAVY 
SHOWERS AND THUNDERSTORMS MONDAY MORNING FOLLOWED BY POSSIBLE
STRONG THUNDERSTORMS MONDAY AFTERNOON AS ITS ATTENDING COLD FRONT
APPROACHES FROM THE WEST. BY TUE THE FRONT MOVES OFFSHORE WITH DRY
AND MUCH LESS HUMID WEATHER OVERSPREADING THE REGION AND
CONTINUING FOR MUCH OF THE REMAINDER OF THE WORKWEEK.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
*** WIDESPREAD HEAVY RAIN AND T-STORMS LATER TONIGHT INTO MONDAY
 MORNING ***

845 PM UPDATE...

QUICK UPDATE TO MODIFY POPS THROUGH MIDNIGHT BASED UPON RADAR
TRENDS.

STORMS OVER WESTERN NEW ENGLAND WERE WEAKENING AS THEY WERE
OUTRUNNING INSTABILITY AXIS. NOT MUCH IN WAY OF ACTIVITY EXPECTED
THROUGH MIDNIGHT OR SO AS WE AWAIT NEXT ROUND OF SHOWERS/STORMS
LIFTING NE FROM PA. HRRR HAS A DECENT HANDLE ON TIMING...ALTHOUGH
IT MAY BE A COUPLE OF HOURS TOO SLOW...BUT BRINGS THIS ACTIVITY
INTO WESTERN NEW ENGLAND 2-5 AM AND FARTHER EAST 5-8 AM.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
*** FEW STRONG TO SEVERE STORMS POSSIBLE MON AFTERNOON ***

IMPRESSIVE SHORT WAVE TROUGH SWINGS ACROSS THE AREA MON WITH 500 MB 
HEIGHTS ON THE ORDER OF -3 SD FROM CLIMO! SURFACE LOW PRES TRACKS 
FROM PA/NY BORDER THEN ACROSS CENTRAL NEW ENGLAND IN THE AFTERNOON. 
WARM FRONTAL CONVECTION WITH HEAVY RAIN IS LIKELY IN THE MORNING BUT 
SHOULD LIFT QUICKLY NORTHEAST AND EXIT THE REGION 12Z-15Z FROM SW TO 
NE. WARM SECTOR THEN OVERSPREADS EASTERN HALF OF THE REGION WITH 
TEMPS RISING INTO THE 80S AND DEW PTS 65-70. THIS WILL YIELD SB 
CAPES OF 1000-2000J/KG ALONG WITH MID LEVEL LAPSE RATES OF 6-6.5C/KM 
AS COOLING OCCURS ALOFT. DEEP LAYER SHEAR IS STRONG AS WELL WITH 0-6 
KM 35 TO 40 KT. FORCING FOR ASCENT WILL BE PROVIDED BY STRONG 
FRONTAL CONVERGENCE AS COLD FRONT APPROACHES FROM THE WEST. IN 
ADDITION LFQ OF ANOMALOUS UPPER LEVEL JET OVER THE AREA WILL PROVIDE 
ENHANCED QG FORCING. THE ONLY WRINKLE IS THE EXACT TIMING AND 
TRAJECTORY OF THE DRY SLOT WHICH MUCH OF THE GUID SUGGEST WILL BE 
OVER SOUTHEAST MA AND VCNTY. THUS THE GREATEST THREAT OF STRONG TO 
SEVERE TSTMS MAY BE FROM INTERIOR CT NORTHEAST INTO CENTRAL AND 
NORTHEAST MA INCLUDING SOUTHERN NH. SPC HAS PLACED THIS REGION IN A 
SEE TEXT. MAIN THREATS WILL BE STRONG TO DAMAGING WINDS/LARGE HAIL 
AND LOW RISK OF AN ISOLATED TORNADO GIVEN STRONG LOW LEVEL SHEAR AND 
HIGH DEW PTS/LOW LCL. 

MON NIGHT...

BIG IMPROVEMENT BEHIND THE FRONTAL PASSAGE WITH MUCH LESS HUMID 
AIRMASS OVERSPREADING THE REGION WITH DEW PTS FALLING INTO THE 50S! 
THIS WILL SUPPORT LOW TEMPS BY TUE MORNING IN THE MU50S INLAND AND 
LOW TO MID 60S ALONG THE COAST.

&&

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

 - SLIGHTLY COOL AND DRY INTO THE END OF JULY!
 - SCATTERED STORMS POSSIBLE ACROSS INTERIOR NEW ENGLAND FOR THURSDAY
 - DECENT CHANCES FOR WET WEATHER FRIDAY INTO SATURDAY 
 - POSSIBLE DAILY OCCURRENCES OF INTERIOR STORMS INTO NEXT WEEK

*/ OVERVIEW AND MODEL PREFERENCE...

INCREDIBLE PATTERN FOR MID-SUMMER! ENSEMBLE SIGNALS AVERAGING WELL-
BELOW NORMAL /-4 TO -5 SD/ FOR BOTH TEMPERATURE AND HUMIDITY ACROSS 
THE NE CONUS AS A BUCKLED PATTERN PREVAILS WITH PREFERRED TROUGHING 
ACROSS THE GREAT LAKES NEIGHBORED BY STRONG RIDGING. ANTICIPATING A 
COOL TO SEASONABLE PATTERN LACKING OF HEAT AND HUMIDITY. 

GOING DEEPER...SLIGHTLY NEGATIVE NAO/AO INDICES INTO THE EARLY-HALF 
OF AUGUST AS THE ENSEMBLE SPREAD OF THE PNA EXHIBITS AN OVERALL 
POSITIVE TREND SIGNALS CONTINUED RIDGING OVER THE E-PACIFIC WITH 
PREFERRED TROUGHING E. NO SURPRISE THAT THE NAEFS/GEFS ANALOGS ALONG 
WITH THE EC-ENSEMBLE HOLD A BUCKLED PATTERN ACROSS THE REGION AS THE 
W-ATLANTIC RIDGE REMAINS STOUT. TREND OF ANOMALOUS BELOW-NORMAL 
CONDITIONS PREVAILS.

THOUGH...PER AFOREMENTIONED ANALOGS/ENSEMBLES...THERE IS A POTENTIAL 
TREND TOWARDS DEAMPLIFICATION. THIS RESONATES WITHIN GLOBAL FORECAST 
SOLUTIONS HIGHLIGHTING A PHASE-SHIFT IN THE MJO CLIMATOLOGICALLY 
RESULTING IN A MORE ZONAL PATTERN WITH WARMER TEMPERATURE ANOMALIES 
OVER NORTH AMERICA. SOME UNCERTAINTY WITH A CONTINUED LOW ANOMALY 
OVER NE CANADA. WILL HAVE TO WAIT AND SEE. 

AS TO THE FORECAST...WILL TREND WITH MORE SEASONABLE CONDITIONS AS 
CYCLONIC FLOW ALOFT PREVAILS USHERING MUCH COOLER AIR S OUT OF 
CANADA. PRECIPITATION CHANCES VARY...BUT WILL NEED TO CLOSELY 
MONITOR INDIVIDUAL IMPULSES AND ACCOMPANYING JET STREAKS THROUGH THE 
OVERALL TROUGH PATTERN. ITS PLAUSIBLE TO SEE PERIODS OF WET WEATHER 
SHOULD THE TROUGH WOBBLE PARENT WITH ITS NEIGHBORING RIDGE AXES. 
WILL BREAK DOWN THE HIGHLIGHTS/CONFIDENCE WITHIN THE DAILY 
DISCUSSION BELOW. 
 
*/ DAY-TO-DAY DETAILS...

TUESDAY INTO WEDNESDAY...

MID- TO UPPER-LEVEL CYCLONIC FLOW USHERS +8-10C H85 AIR INTO S NEW 
ENGLAND AS THE MAJORITY OF ACTIVITY/DYNAMICS IS SHUNTED OFFSHORE. 
WEAK HIGH PRESSURE WITH LIGHT WINDS SLOWLY TURNING S TOWARDS THE END 
OF THE PERIOD. LOTS OF DRY AIR IN PLACE AS IT CONTINUALLY WRAPS INTO 
THE OCCLUSION AS NEW ENGLAND FINDS ITSELF WITHIN THE LFQ OF THE 
UPPER-LEVEL JET...A FAVORABLE REGION OF SUBSIDENCE. 

WILL PREVAIL WITH SEASONABLE CONDITIONS WITH SEA-BREEZES ALONG THE 
SHORES. A DRY FORECAST WITH ACTIVITY HELD WELL N/W PARENT WITH THE 
OCCLUSION AND BETTER COLD-POOL. PARTLY CLOUDY CONDITIONS DURING THE 
DAY WITH DIURNAL CUMULUS. 

THURSDAY...

MAIN IMPULSE ASSOCIATED WITH THE OCCLUSION EJECTS CYCLONICALLY OVER 
THE E GREAT LAKES. EXPECT SUBSEQUENT FALLING HEIGHTS COLOCATED WITH
STRONG ENHANCED ASCENT AND DEEP-LAYER LIFT /ESPECIALLY WITHIN THE
LFQ OF AN ATTENDANT JET STREAK/.

SHOULD SEE DIURNALLY-DRIVEN ACTIVITY DEVELOP ACROSS INTERIOR NEW 
ENGLAND BENEATH COOLER AIR ALOFT AND CYCLONIC FLOW. SEVERITY SHOULD 
BE LIMITED LACK OF INSTABILITY WITH POOR LAPSE RATES AND ABUNDANCE 
OF DRY AIR...DESPITE DECENT SW-NE UNI-DIRECTIONAL SHEAR. EXPECT 
ISOLATED TO SCATTERED ACTIVITY AWAY FROM THE SHORELINES WHICH SHOULD 
REMAIN FAIRLY QUIET UNDER THE INFLUENCE OF ONSHORE MARITIME AIR. 

FRIDAY INTO SATURDAY...

PACIFIC-ORIGIN ENERGY ROUNDING THE BROADER TROUGH PATTERN STREAMS NE 
ACROSS NEW ENGLAND. MID- TO UPPER-LEVEL TIGHTENING OF THE PRESSURE 
GRADIENT RESOLVES A FASTER JET STREAK SUBSEQUENTLY. SHOULD SEE A 
BROADSCALE REGION OF FAVORABLE ASCENT DEVELOP ACROSS NEW ENGLAND.

BUT CHALLENGES PREVAIL BETWEEN LIKELY DIURNALLY DRIVEN ACTIVITY 
ACROSS INTERIOR NE-CONUS AND LINGERING OFFSHORE FRONTAL BOUNDARY. 
ANTICIPATING A REGION BETWEEN OF DRIER WEATHER...JUST WHERE AND HOW 
IT EVOLVES ENTERTAINS A FAIR AMOUNT OF UNCERTAINTY. 

EC/GEFS TREND WITH ACTIVITY MAINLY ACROSS THE INTERIOR WHEREAS THE 
27.12Z GFS RETROGRADES THE OFFSHORE FRONT PARENT WITH A FRONTAL LOW 
CONSEQUENTIAL OF THE AFOREMENTIONED PACIFIC ENERGY. ALL SOLUTIONS 
SHOW THE MAIN LOW OVER THE GREAT LAKES LIFTING OUT OF THE REGION TO 
THE NE.  

SUNDAY INTO EARLY NEXT WEEK...

THOUGH PATTERN DEAMPLIFICATION IS POSSIBLE...CYCLONIC FLOW PREVAILS 
BEHIND THE EARLIER PACIFIC IMPULSE. WILL HOLD WITH THE TYPICAL 
SUMMER-TIME PATTERN OF CONVECTION ACROSS THE INTERIOR WITH QUIET 
WEATHER ALONG THE SHORES.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...

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

7 PM UPDATE...

ONLY CHANGE TO 18Z TAFS WAS TO ACCOUNT FOR TSTMS VICINITY OF
BAF/BDL THRU 00Z/01Z. OTHERWISE NO CHANGES. EARLIER DISCUSSION
BELOW.

================================================================

MODERATE CONFIDENCE THROUGH MON...THEN INCREASING CONFIDENCE MON
NIGHT.

THRU 00Z...SHOWERS AND SCATTERED TSTMS EXIT EASTERN MA 3PM OR
4PM...THEN ANY NEW CONVECTION SHOULD BE VERY ISOLATED IF AT ALL.
ANY LINGERING MVFR ACROSS EASTERN MA WILL IMPROVE TO LOW END VFR
BY 4 PM. 

TONIGHT...MARGINAL MVFR/VFR TO START THEN LOWERING TO MVFR/IFR AS
THE NIGHT PROGRESS AS FOG DEVELOPS. ANOTHER ROUND OF HEAVY SHOWERS
WITH SCT TSTMS DEVELOPS 07Z-10Z FROM SW TO NE. HEAVY RAIN AND
GUSTY WINDS ARE THE MAIN THREATS.

MONDAY...IFR/LIFR IN THE MORNING WITH SCT SHRA/TSTMS LIFTS NE INTO
ME 12Z TO 15Z FROM SW TO NE. THEN LOW END VFR MOST TERMINALS BY
AFTERNOON WITH ANOTHER ROUND OF TSTMS POSSIBLE EXPECT ACROSS RI
AND SOUTHEAST MA WHERE RISK OF SHRA/TSTMS IS MUCH LOWER. A FEW
STRONG STORMS ARE POSSIBLE WITH HEAVY RAIN AND GUSTY WINDS.

MONDAY NIGHT...IMPROVING WEATHER AFTER 03Z OR SO AS COLD FRONT
SWEEPS ACROSS THE AREA ALONG WITH A WIND SHIFT TO THE WNW. ANY
LINGERING SHOWERS/TSTMS ACROSS NORTHERN MA AND SOUTHWEST NH AND
MVFR CONDITIONS WILL IMPROVE TO VFR AFTER 03Z OR SO.

KBOS TAF...MODERATE CONFIDENCE. SHOWERS/STORMS JUST ABOUT OFFSHORE
AS OF 230 PM. LITTLE IF ANY NEW CONVECTION UNTIL 09Z-12Z MON.
LOWERING TO MVFR/IFR TONIGHT IN FOG...THEN IMPROVING TO VFR MON
MIDDAY. A FEW STRONG STORMS POSSIBLE MON AFTN.

KBDL TAF...MODERATE CONFIDENCE. BRIEF MVFR CONDITIONS IN STORMS
THRU 00Z-01Z THEN IMPROVING TO VFR. THEN CONDITIONS LOWER 06Z-09Z
TO MVFR/IFR IN SHOWERS AND TSTMS. HEAVY RAIN AND GUSTY WINDS
POSSIBLE. CONDITIONS IMPROVE TO VFR MON MIDDAY WITH ANOTHER ROUND
OF AFTN T-STORM POSSIBLE. A FEW STRONG STORMS POSSIBLE.

OUTLOOK...TUESDAY THROUGH FRIDAY...MODERATE CONFIDENCE.

TUESDAY AND WEDNESDAY...HIGH CONFIDENCE. VFR WITH LIGHT WINDS 
GRADUALLY TURNING S. SEA-BREEZES ALONG THE SHORES.

THURSDAY...MODERATE CONFIDENCE. ISOLATED-SCATTERED SHRA/TSRA 
POSSIBLE OVER INTERIOR TERMINALS WITH MIX OF MVFR-IFR CONDITIONS. 
SEA-BREEZES ALONG THE SHORES.

FRIDAY...LOW CONFIDENCE. SCATTERED-WIDESPREAD SHRA/TSRA. MAIN FOCUS 
ACROSS SE/W/CENTRAL NEW ENGLAND. COULD BE A LULL IN ACTIVITY AROUND 
THE BOS-PVD CORRIDOR.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

MODERATE CONFIDENCE THROUGH MON NIGHT

TONIGHT...PATCHY DENSE FOG POSSIBLE. SHOWERS AND TSTMS REDEVELOP 
TOWARD DAYBREAK. A FEW STRONG STORMS POSSIBLE ALONG WITH VERY HEAVY 
RAIN. 

MONDAY...PATCHY DENSE FOG IN THE MORNING BURNS OFF/ERODES BY EARLY 
AFTERNOON. EARLY MORNING SHOWERS AND TSTMS TAPER OFF FOLLOWED BY A 
NEW ROUND OF SHOWERS/TSTMS MID TO LATE AFTERNOON. A FEW OF THESE 
STORMS MAY BE STRONG ALONG WITH HEAVY DOWNPOURS. SSW WINDS MAY 
APPROACH 25 KT AS THE AFTERNOON PROGRESSES ESPECIALLY NEAR SHORE.

MON NIGHT...COLD FRONT SWEEPS ACROSS THE WATERS WITH A WIND SHIFT
TO THE WNW ALONG WITH DRY WEATHER AND GOOD VSBY.

OUTLOOK...TUESDAY THROUGH FRIDAY...MODERATE CONFIDENCE.

TUESDAY THROUGH THURSDAY...MODERATE CONFIDENCE. LIGHT WINDS 
ASSOCIATED WITH HIGH PRESSURE SHOULD ALLOW FOR TRANQUIL BOATING 
WEATHER AS SEAS DIMINISH. 

FRIDAY...MODERATE CONFIDENCE. WHILE BOATING CONDITIONS REMAIN 
TRANQUIL...WILL SEE INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS 
DEVELOP ACROSS THE WATERS.

&&

.EQUIPMENT...
OUR DOPPLER RADAR IS DOWN. A TECHNICIAN IS ON THE WAY IN. WE
APOLOGIZE FOR ANY INCONVENIENCE.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 7 AM TO 7 PM EDT 
     MONDAY FOR ANZ235-250-254>256.

&&

$$
SYNOPSIS...NOCERA
NEAR TERM...JWD
SHORT TERM...NOCERA
LONG TERM...SIPPRELL
AVIATION...NOCERA/SIPPRELL
MARINE...NOCERA/SIPPRELL
EQUIPMENT...



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