Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Graphics & Text | 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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 111742 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 140 PM 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/...
-- Changed Discussion --
140 PM UPDATE... BEAUTIFUL MID JULY DAY IN PROGRESS WITH PARTLY TO MOSTLY SUNNY SKIES AND COMFORTABLE HUMIDITY LEVELS. LATE AFTERNOON HIGHS WILL TOP OUT MAINLY IN THE 80 TO 85 DEGREE RANGE...EXCEPT 70S ON THE IMMEDIATE COAST AS A RESULT OF SEA BREEZES. DRY WEATHER EXPECTED...BUT LOW PROBABILITY OF A SPOT SHOWER ON THE SEA BREEZE FRONT ACROSS RI/SOUTHEAST THROUGH LATE AFTERNOON WITH MARGINAL INSTABILITY.
-- End Changed Discussion --
&& .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 /18Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE. THIS AFTERNOON THROUGH SATURDAY NIGHT...VFR OTHER THAN PERHAPS A TOUCH OF LATE NIGHT/EARLY MORNING PATCHY GROUND FOG IN THE TYPICALLY PRONE LOCATIONS. KBOS TAF...HIGH CONFIDENCE IN TAF. EAST SEA BREEZE TO BECOME SOUTHEAST AND PERSIST THROUGH LATE EVENING. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...SUNDAY THROUGH TUESDAY.... 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.
-- End Changed Discussion --
&& .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...FRANK/NOCERA 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.