Area Forecast Discussion
Issued by NWS Boston, MA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KBOX 111352
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
950 AM EDT FRI JUL 11 2014

.SYNOPSIS...
TRANQUIL WEATHER TODAY AND TOMORROW AS HIGH PRESSURE SETTLES OVER
THE REGION. UNSETTLED WEATHER IN THE FORM OF SHOWERS AND
THUNDERSTORMS RETURNS LATE SUNDAY INTO EARLY NEXT WEEK. THERE IS
THE POTENTIAL FOR STRONG WINDS AND HEAVY RAINFALL.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...

950 AM UPDATE...

A BEAUTIFUL JULY DAY IN PROGRESS ACROSS SOUTHERN NEW ENGLAND AS HIGH
PRESSURE BUILDS INTO THE REGION.  MOST OF THE MID LEVEL CLOUDINESS
WAS NOW CONFINED TO THE CAPE AND ISLANDS...WITH SUNNY SKIES
ELSEWHERE.

EXPECT PARTLY TO MOSTLY SUNNY SKIES THROUGH THE AFTERNOON WITH
COMFORTABLE HUMIDITY FOR MOST OF THE REGION.  HIGHS WILL MAINLY BE
IN THE LOWER TO MIDDLE 80S...EXCEPT 70S ALONG THE IMMEDIATE COAST AS
A RESULT OF SEA BREEZES DEVELOPING.

DRY WEATHER EXPECTED...BUT CAN/T RULE OUT A BRIEF SPOT SHOWER OR TWO
THIS AFTERNOON ACROSS EASTERN CT/RI/SOUTHEAST MA WITH SOME LEFT OVER
MARGINAL INSTABILITY.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SATURDAY/...
TONIGHT...

HIGH PRESSURE WILL CONTINUE TO DOMINATE ACROSS SOUTHERN NEW ENGLAND
TONIGHT. THIS WILL ALLOW FOR A WEAK PRESSURE GRADIENT AND WITH
MOSTLY CLEAR SKIES COULD SEE SOME RADIATIONAL COOLING. TEMPS WILL
GENERALLY BE IN THE UPPER 50S WITH LOW 60S ACROSS THE METRO REGIONS.
PATCHY FOG MAY DEVELOP ESPECIALLY ACROSS VALLEY REGIONS BUT HAVE
A LOWER CONFIDENCE.

TOMORROW...

HIGH PRESSURE WILL BEGIN TO SLIDE EASTWARD ON SATURDAY. MOISTURE
WILL SLOWLY INCREASE AS WINDS WILL SWITCH TO THE SOUTHWEST NEAR THE
END OF THE DAY. THIS WILL ALLOW FOR MORE DIURNAL CU TO DEVELOP.
STILL A PRETTY WEAK PRESSURE GRADIENT SO SEA BREEZE DEVELOPMENT
LOOKS LIKELY ALONG BOTH COASTLINES.

FULL MOON WILL OCCUR OVER THE WEEKEND ALLOWING FOR THE
ASTRONOMICAL HIGH TIDES TO OCCUR. THERE COULD BE SOME MINOR
SPLASHOVER ACROSS SCITUATE AND P-TOWN HARBOR. OTHERWISE EXPECT
VERY LITTLE IMPACT ON THE LATE SATURDAY HIGH TIDE.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
HIGHLIGHTS...

* MORE HUMID AND BREEZY SUNDAY...SHOWERS POSSIBLE LATE
* STRONG TO SEVERE THUNDERSTORMS & HEAVY RAINFALL POSSIBLE MON/TUE
* TREND TOWARD DRIER AND LESS HUMID WEATHER MID TO LATE NEXT WEEK

SYNOPTIC OVERVIEW AND MODEL PREFERENCES...

GUIDANCE CONTINUES TO SIMULATE AN EVOLVING HIGHLY ANOMALOUS
AMPLIFIED NORTHERN STREAM THIS PERIOD WITH A FULL LATITUDE RIDGE
DEVELOPING ACROSS THE WESTERN CONUS INTO CANADA. DOWNSTREAM A POTENT
CLOSED LOW ADVECTS SOUTHWARD INTO THE GREAT LAKES EARLY NEXT WEEK.
THIS YIELDS A DEEP MOIST SW FLOW ALONG THE EASTERN SEABOARD WITH AN
INFLUX OF GULF AND ATLANTIC MOISTURE INTO NEW ENGLAND. A STRONG
FRONTAL ZONE WILL ACCOMPANY THIS CLOSED LOW AND WILL BECOME THE
FOCUS FOR CONVECTION AND HEAVY RAINFALL EARLY NEXT WEEK ACROSS NEW
ENGLAND. ANOMALOUS JET DYNAMICS ASSOCIATED WITH THIS FEATURE
COMBINED WITH PEAK CLIMATOLOGICAL HEATING WILL INCREASE THE RISK FOR
STRONG TO SEVERE STORMS HERE IN SOUTHERN NEW ENGLAND. ALSO GIVEN THE
DEEP SOUTHWEST FLOW THESE STORMS WILL HAVE THE POTENTIAL OF BACK
BUILDING AND TRAINING OVER THE SAME AREA YIELDING A RISK OF FLASH
FLOODING. AS FOR MODEL GUIDANCE...BOTH THE 12Z GEFS AND ECENS
ENSEMBLES ALONG WITH THE 00Z DETERMINISTIC RUNS OF GFS AND ECMWF ARE
IN VERY GOOD AGREEMENT ON TROUGH/RIDGE AMPLITUDE AND TIMING OF
FRONTAL PASSAGE. THUS WILL BLEND ALL DATA SOURCES FOR THIS PORTION
OF THE FORECAST.

DAILY DETAILS...

SAT NIGHT...

QUIET/DRY WEATHER AS HIGH PRES LINGERS ALONG THE COAST. SEASONABLE
TEMPS WITH LOWS IN THE LOW TO MID 60S. TOLERABLE HUMIDITY WITH DEW
PTS IN THE U50S TO L60S.

SUNDAY...

BECOMING MORE HUMID AND BREEZY AS LOW LEVEL WARM AIR ADVECTION
INCREASES AS SURFACE HIGH DRIFTS OFFSHORE. NICE WEATHER LINGERS MUCH
OF THE DAY ACROSS EASTERN NEW ENGLAND PER GOOD MODEL AGREEMENT ON
WARM ADVECTION PRECIP ARRIVING AFTER 18Z ACROSS WESTERN NEW ENGLAND
AND PROBABLY NOT UNTIL AFTER 00Z OVER RI AND EASTERN MA. THUS DRY
WEATHER FOR MUCH OF THE DAYLIGHT HOURS ACROSS RI AND EASTERN MA.

EARLY NEXT WEEK...

WARM AND MUGGY CONDITIONS AHEAD OF A STRONG FRONTAL BOUNDARY
APPROACHING THE REGION FROM THE WEST. AS MID LEVEL FLOW AMPLIFIES
AND BACKS...DEEP S-SW FLOW ALOFT DEVELOPS ALONG THE EASTERN
SEABOARD. THIS RESULTS IN A SLOW MOVING FRONTAL BOUNDARY WITH AN
INFLUX OF GULF AND ATLC MSTR. STRONG JET DYNAMICS COUPLED WITH AT
LEAST MODEST INSTABILITY INCREASES THE RISK OF STRONG TO SEVERE
STORMS ALONG AND AHEAD OF THE APPROACHING FRONT MON AND TUE. IN
ADDITION THE DEEP S-SW FLOW ALOFT WILL PROVIDE AN ENVIRONMENT
FAVORABLE FOR BACK BUILDING STORMS AND TRAINING OVER THE SAME AREA.
THUS A RISK OF FLASHING FLOODING.

MID TO LATE NEXT WEEK...

ENSEMBLES AND DETERMINISTIC GUIDANCE SUGGEST A FRONTAL PASSAGE
AROUND WED ALONG WITH MID TO UPPER TROUGH DEAMPLIFYING AS IT LIFTS
NE INTO ONTARIO AND QUEBEC. THIS SUPPORTS A TREND TOWARD DRIER AND
LESS HUMID WEATHER MID TO LATE NEXT WEEK.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH SATURDAY/...HIGH CONFIDENCE.

7 AM UPDATE...NO MAJOR CHANGES FROM 06Z TAFS. MVFR VSBYS IN PATCHY
SHALLOW FOG OVER CAPE COD AND THE ISLANDS WILL IMPROVE TO VFR BY
15Z. EARLIER DISCUSSION BELOW.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

TODAY TIL TOMORROW...VFR THROUGH THE PERIOD. SEA BREEZES ONCE
AGAIN LIKELY AT NEAR SHORE TERMINALS FOR TODAY AND TOMORROW.
LOW CONFIDENCE ON PATCHY FOG ACROSS THE SOUTH COASTLINE.

KBOS TAF...HIGH CONFIDENCE IN TAF. SEA BREEZE SHOULD START 13-15Z
TODAY.

KBDL TAF...HIGH CONFIDENCE IN TAF.

OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...

SATURDAY NIGHT...HIGH CONFIDENCE FOR VFR AND DRY WEATHER.

SUNDAY...VFR BUT LOW RISK OF MVFR LATE IN THE DAY WESTERN NEW
ENGLAND AS SHOWERS ENTER THIS AREA. HIGH CONFIDENCE ON TRENDS BUT
LOWER CONFIDENCE ON EXACT TIMING.

SUNDAY NIGHT THROUGH TUESDAY...LOW TO MODERATE CONFIDENCE.  MAINLY
VFR DURING THE DAYLIGHT HOURS BUT LOWERING TO MVFR/IFR AT NIGHT IN
AREAS OF FOG. ALSO MVFR IN SCT SHOWERS/TSTMS.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /TODAY THROUGH SATURDAY/...HIGH CONFIDENCE.

A COLD FRONT WILL SLOWLY MOVE SOUTH OF THE WATERS TODAY AND
TOMORROW. A FEW ISOLATED SHOWERS MAY OCCUR TODAY BUT DRY WEATHER
SHOULD PREVAIL BY THE AFTERNOON LASTING THROUGH THE PERIOD. WINDS
AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH
SATURDAY.

OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...

SATURDAY NIGHT...QUIET BOATING WEATHER WITH LIGHT SSW WINDS AND DRY
WEATHER.

SUNDAY...SSW WINDS INCREASE AS FRONT APPROACHES. SHOWERS/TSTMS HOLD
OFF UNTIL SUN NIGHT.

MON AND TUE...PERSISTENT MODEST SSW WINDS 15-20 KT WITH HIGHER
GUSTS. SCT TSTMS WITH HEAVY RAIN AND STRONG WINDS POSSIBLE. PATCHY
DENSE FOG POSSIBLE ESPECIALLY AT NIGHT AND EARLY MORNING.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.

&&

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.