Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 111911 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 311 PM EDT FRI JUL 11 2014 .SYNOPSIS... DRY AND BEAUTIFUL MID JULY WEATHER CONTINUES THROUGH SATURDAY. HUMID AND UNSETTLED WEATHER RETURNS LATE SUNDAY INTO EARLY NEXT WEEK WITH PERIODS OF SHOWERS AND THUNDERSTORMS. THERE WILL BE THE POTENTIAL FOR SOME SEVERE WEATHER AND LOCALIZED FLASH FLOODING...BUT ITS TOO EARLY TO GIVE MORE DETAILS. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... HIGH PRESSURE OVERHEAD WILL RESULT IN A VERY NICE AND COMFORTABLE NIGHT FOR THE MIDDLE OF JULY. DIURNAL CUMULUS CLOUDS WILL DISSIPATE AFTER SUNSET ALLOWING SKIES TO BECOME MOSTLY CLEAR. GIVEN THE RELATIVELY DRY AIRMASS IN PLACE FOR THIS TIME OF YEAR...LOWS SHOULD FALL WELL DOWN INTO THE 50S IN MOST LOCALES. EVEN THE URBAN HEAT ISLANDS OF DOWNTOWN BOSTON/PROVIDENCE SHOULD SEE LOWS BOTTOM OUT BETWEEN 60 AND 65. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... ***BEAUTIFUL START TO THE WEEKEND*** SATURDAY... HIGH PRESSURE SLOWLY SLIDES OFF THE COAST ON SATURDAY. THIS WILL ALLOW FOR A RETURN SOUTH TO SOUTHWEST FLOW OF AIR AND TEMPS A FEW DEGREES WARMER THAN TODAY. HIGHS SHOULD TOP OUT MAINLY IN THE MIDDLE TO UPPER 80S...ALTHOUGH A FEW DEGREES COOLER ON THE SOUTH COAST WITH SOUTHERLY WINDS BLOWING OFF THE OCEAN. DEWPOINTS WILL BE BETWEEN 55 AND 60...SO HUMIDITY WILL BE HELD IN CHECK FOR THIS TIME OF YEAR. PARTLY TO MOSTLY SUNNY SKIES EXPECTED AND THERE IS LITTLE FORCING/MOISTURE AVAILABLE...SO WILL CONTINUE WITH A DRY FORECAST. SATURDAY NIGHT... HIGH PRESSURE CONTINUES TO MOVE EAST AND WAY FROM THE REGION. HOWEVER...ANY FORCING FOR PRECIPITATION WILL REMAIN TO OUR WEST...SO ANOTHER DRY NIGHT IN STORE FOR THE REGION. LOW TEMPS WILL BE MILDER WITH READINGS DROPPING INTO THE UPPER 50S TO MIDDLE 60S BY DAYBREAK MONDAY. && .LONG TERM /SUNDAY THROUGH FRIDAY/... 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 /19Z FRIDAY THROUGH WEDNESDAY/... 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. TONIGHT 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. EASTERLY SEA BREEZE TO BECOME SOUTHEAST AND PERSIST THROUGH LATE EVENING BEFORE DISSIPATING. 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. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE. NICE BOATING WEATHER THROUGH SATURDAY NIGHT. WEAK PRESSURE GRADIENT WILL KEEP WINDS/SEAS BELOW SCA THRESHOLDS THROUGH SATURDAY NIGHT. VARIABLE WINDS WILL TONIGHT WILL BECOME SOUTHERLY AT 5 TO 15 KNOTS EARLY SATURDAY AS HIGH PRESSURE MOVES OFF THE COAST. WINDS WILL THEN BECOME SOUTH SOUTHWEST AT THE SAME SPEEDS SATURDAY NIGHT. OUTLOOK...SUNDAY THROUGH TUESDAY... 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...FRANK NEAR TERM...FRANK SHORT TERM...FRANK LONG TERM...NOCERA AVIATION...FRANK/NOCERA MARINE...FRANK/NOCERA

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