Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 291833 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 233 PM EDT FRI AUG 29 2014 .SYNOPSIS...
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HIGH PRESSURE CENTERED OVER THE GREAT LAKES WILL BUILD OVER NEW ENGLAND FEATURING MILD DAYS AND COOL NIGHTS ALONG WITH DRY WEATHER AND LOW HUMIDITY TODAY AND SATURDAY. A FRONT WILL SLOWLY PUSH ACROSS NEW ENGLAND LATE SUNDAY AND MONDAY BRINGING A PERIOD OF SHOWERS AND SCATTERED THUNDERSTORMS. SOME SHOWERS AND A FEW THUNDERSTORMS MAY LINGER INTO TUESDAY. WARM...DRY CONDITIONS LOOK TO SET UP BY LATE NEXT WEEK.
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&& .NEAR TERM /UNTIL 7 PM THIS EVENING/...
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2 PM UPDATE... SCT-BKN SCU HAVE DEVELOPED ACROSS THE REGION IN RESPONSE TO ONSHORE/SEABREEZE PROVIDING LOW LEVEL MOISTURE AND CONVERGENCE. IN ADDITION FLOW ALOFT REMAINS CYCLONIC. HOWEVER LIFT AND MOISTURE IS VERY SHALLOW SO NOT EXPECTING ANY PRECIP...JUST SOME FAIR WEATHER CLOUDS FROM TIME TO TIME. THUS ONLY CHANGE TO THE PREVIOUS FORECAST WAS TO INCREASE SKY COVER A BIT DURING PEAK HEATING HOURS AND THEN SLOWLY ERODE CLOUD COVER TOWARD SUNSET. OTHERWISE PREVIOUS FORECAST REMAINS ON TRACK WITH COOLER TEMPS TODAY THAN YESTERDAY GIVEN CORE OF COOLER AIRMASS IS NOW OVER THE REGION. ALSO LEFTOVER SURF FROM POST TROPICAL CRISTOBAL CONTINUES TO SUBSIDE.
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&& .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SATURDAY/... HIGH PRESSURE MOVES OFFSHORE TONIGHT AND REMAINS IN PLACE TO OUR EAST ON SATURDAY. THIS WILL BRING INCREASING FLOW FROM THE SOUTH...EXCEPT SOUTHEAST NEAR THE EAST MASS COAST. DEW POINTS WILL START TO RISE...BUT THIS TREND MAY HOLD OFF UNTIL THE FLOW PICKS UP ON SATURDAY. AT THAT POINT...DEW POINT VALUES WILL CLIMB THROUGH THE 50S TO NEAR 60 BY SATURDAY EVENING. TONIGHT... THE LIGHT WIND/FAIR SKIES WILL ALLOW ANOTHER COOL NIGHT TONIGHT WITH SURFACE TEMPS IN THE UPPER 40S AND 50S. THIS WILL BE CLOSE ENOUGH TO SATURATION FOR PATCHY FOG. BEST CHANCES WOULD BE IN THE CT VALLEY AND IN THE LOW SPOTS OF EASTERN MASS. SATURDAY... SUNSHINE THROUGH CIRRUS ON SATURDAY WILL MEAN A PLEASANT DAY. THE SUNSHINE WILL BE FILTERED A LITTLE...BUT TEMPS IN THE MIXED LAYER WILL BE A LITTLE MILDER THAN TODAY. SO SFC TEMPS SHOULD BE AT LEAST THE SAME AS TODAY AND PROBABLY A LITTLE MILDER. BASED ON A MIXED LAYER TO 900 MB OR A LITTLE ABOVE...WE WENT WITH MAX TEMPS 75 TO 80. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... OVERVIEW AND MODEL PREFERENCES... NOTING OVERALL CHANGES ON THE MEDIUM RANGE MODELS TOWARD A BROAD RIDGING PATTERN DEVELOPING ACROSS THE EASTERN SEABOARD...MORE OF A TYPICAL SUMMER PATTERN THOUGH LATE IN THE SEASON...AS OPPOSED TO THE LONG WAVE TROUGHING THAT HAS BEEN ACROSS THE EAST OVER THE LAST SEVERAL MONTHS. WILL CONTINUE WITH TREND OF BROAD TROUGHING TO START OFF THIS PORTION OF THE FORECAST...THEN TRANSITION TOWARD NEARLY ZONAL NORTHERN TIER UPPER FLOW WHICH THE MODELS/ENSEMBLES HAVE BEEN ADVERTISING OVER THE LAST FEW NIGHTS. MODEL SOLUTION DIFFERENCES IN THE STEERING CURRENTS WORK IN BEGINNING EARLY NEXT WEEK...SO SOME QUESTION AS TO TIMING OF SURFACE SYSTEMS TO THE EASTERN SEABOARD. LEANED TOWARD A BLEND OF AVAILABLE GUIDANCE THROUGH LATE MONDAY... WHICH SHOWED GOOD RUN TO RUN CONSISTENCY OVER THE LAST SEVERAL DAYS. FOR TUESDAY AND BEYOND...WENT CLOSER A BLEND OF THE EC/GEFS ENSEMBLE MEANS. WITH SOLUTION TIMING ISSUES...HAVE LOWER CONFIDENCE DURING THIS TIMEFRAME. DETAILS... SATURDAY NIGHT THROUGH SUNDAY NIGHT... LARGE SURFACE HIGH SLOWLY PUSHES E OF NEW ENGLAND DURING THIS TIMEFRAME. LOOKS LIKE THIS WILL BE SLOW TO CLEAR THE COAST...SO HAVE CARRIED DRY CONDITIONS. PERSISTENT SW WINDS WILL BRING IN MORE HUMIDITY TOWARD THE REGION ESPECIALLY ON SUNDAY AHEAD OF AN APPROACHING FRONT. DEWPTS FORECASTED TO INCREASE TO THE MID 60S TO AROUND 70 DEGS DURING SUNDAY. WILL SEE PATCHY FOG DEVELOP SAT NIGHT MAINLY AFTER MIDNIGHT WITH LOWS IN THE LOWER-MID 60S. A FRONTAL SYSTEM WILL SHIFT SLOWLY E DURING SUNDAY...SO WILL SEE CLOUDS INCREASING AS WELL AS THE HUMIDITY. WILL START TO SEE SHOWERS AND SOME SCT THUNDERSTORMS PUSH INTO WESTERN AREAS DURING THE AFTERNOON...WITH THE BEST SHOT FOR PRECIP DURING SUN NIGHT. MODELS SIGNALING A SHARP INCREASE IN PWATS AS WELL...ON THE ORDER OF 2.1 TO 2.3 INCHES...WHICH RUNS CLOSE TO 3 SD ABOVE NORMAL FOR EARLY SEPTEMBER BY SUN NIGHT. SO...WILL PROBABLY SEE SOME HEAVY DOWNPOURS WITH SOME OF THESE SHOWERS AND STORMS. PRETTY GOOD INSTABILITY ALSO MOVING ACROSS WITH K INDICES IN THE LOWER-MID 30S...ALONG WITH A BAND OF BELOW ZERO SHOWALTER INDICES CROSSING THE REGION SUN NIGHT. HIGHS ON SUNDAY WILL BE STEAMY...IN THE LOWER-MID 80S...WITH LOWS SUN NIGHT BETWEEN 65 AND 70 DEGREES. MONDAY... FRONT CROSSES THE REGION AS IT WASHES OUT...BUT MOISTURE LINGERS ACROSS THE REGION ALONG WITH THE HIGH HUMIDITIES. KEPT CHANCE POPS GOING DURING THE DAY INTO EVENING HOURS MAINLY DUE TO DIURNAL HEATING. ALSO HAVE MENTIONED CHANCE FOR THUNDER ACROSS CENTRAL AND SOUTHERN AREAS. EXPECT PRECIP TO WEAKEN MON NIGHT. WILL REMAIN WARM AND HUMID. TUESDAY... ANOTHER COLD FRONT APPROACHES...SO WILL SEE ANOTHER ROUND OF SCT SHOWERS/TSTMS. WARM AND HUMID CONDITIONS WILL CONTINUE WITH HIGHS AGAIN IN THE LOWER-MID 80S. THE FRONT SHOULD CLEAR THE COAST TUE NIGHT...BUT WIND FLOW REMAINS FROM THE W WITH THE DRIER AIR REMAINING N OF THE REGION. WEDNESDAY AND THURSDAY... SOMEWHAT DRIER AIR WILL WORK INTO THE REGION DURING THIS TIMEFRAME...BUT TEMPS LOOK TO REMAIN ON THE WARM SIDE AS A RIDGE BUILDS ACROSS THE EASTERN U.S. STILL SOME QUESTIONS WITH THE EVOLVING UPPER LEVEL PATTERN ACROSS THE CONUS...SO LOWER CONFIDENCE ON THIS PORTION OF THE FORECAST. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. 2 PM UPDATE... FORECAST CONFIDENCE MODERATE TO HIGH. CIGS AND VSBYS WEIGHTED MORE HEAVILY ON NAM AND ITS METMOS THAN GFS AND MAVMOS. THRU 00Z...VFR WITH SCT-BKN045-055. LIGHT EAST WINDS WILL BECOME SOUTHEAST. DRY WEATHER/RUNWAYS. AFTER 00Z...VFR ALONG WITH WINDS BECOMING CALM INLAND AND LIGHT SE ALONG WITH COAST. SOME PATCHY MVFR/IFR IN FOG TOWARD SUNRISE IN THE INTERIOR VALLEYS AND IN THE LOW LYING SECTIONS OF EASTERN MA. SATURDAY...MARGINAL MVFR-VFR IN SCT-BKN035-045 DURING THE AFTERNOON HOURS. LOW RISK OF MORE WIDESPREAD MVFR CIGS BKN020-030 ACROSS RI AND SOUTHEAST MA. SE WINDS BECOMING MORE S IN THE AFTERNOON. DRY WEATHER/RUNWAYS CONTINUE. SAT NIGHT...INCREASING RISK OF MVFR CIGS AND VSBYS. SHOULD REMAIN DRY. S WINDS BECOME MORE SSW DURING THE NIGHT. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...SUNDAY NIGHT THROUGH TUESDAY... SUNDAY...MODERATE CONFIDENCE. MAINLY VFR. S/SW WINDS GUSTING UP TO 20-25 KT DURING SUNDAY. MVFR- IFR CIGS/VSBYS POSSIBLE ALONG THE S COAST SATURDAY NIGHT. CHANCE FOR SHRA/TSRA ACROSS CENTRAL AND WESTERN AREAS BEGINNING AROUND MIDDAY SUNDAY ONWARD. SUNDAY NIGHT AND MONDAY...LOW CONFIDENCE. MIX OF LOW END VFR TO MVFR. WIDESPREAD SHRA ACROSS THE TERMINALS. POSSIBLE TSRA ACROSS THE INTERIOR MONDAY. CONTINUED S/SW WINDS. TUESDAY...MODERATE CONFIDENCE. COLD FRONT SWEEPING ACROSS THE TERMINALS LATE TUE/TUE NIGHT. LOW END VFR. CHANCE OF SHRA/TSRA. WINDS BACKING OUT OF W BEHIND THE FRONT TUE NIGHT.
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&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. 10 AM UPDATE... SE SWELLS CONTINUE TO SLOWLY DIMINISH ALONG WITH N-NE WINDS AS HIGH PRES CREST OVER CAPE COD LATER TODAY. EARLIER DISCUSSION BELOW. SHORT-TERM /TONIGHT THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE. TODAY...HIGH PRESSURE BUILDS OVER THE WATERS. THIS MEANS NORTH WINDS WILL DIMINISH AND BECOME LIGHT. LIGHT WINDS WILL ALLOW SEA BREEZES TO DEVELOP NEAR SHORE. A 5 FOOT SOUTH SWELL FROM CRISTOBAL LINGERS ON THE EXPOSED WATERS BUT IS SHOWING A LOWERING TREND. WE WILL CONTINUE THE SMALL CRAFT ADVISORY FOR A FEW MORE HOURS...ENDING IT ON THE SOUNDS BY 8 AM...AND ON ALL OUTER WATERS BY 2 PM. TONIGHT...SEAS WILL BE BELOW 5 FEET AND WINDS LIGHT. SATURDAY...WINDS INCREASE FROM THE SOUTH...BUT SEA WILL REMAIN BELOW 5 FEET. SATURDAY NIGHT AND SUNDAY...MODERATE CONFIDENCE. S-SW WINDS GUSTING UP TO 20 KT MAINLY ON THE SOUTHERN OUTER WATERS ALONG WITH SEAS BUILDING UP TO AROUND 5 FT. PATCHY FOG WITH REDUCED VSBYS. SCT SHOWERS/TSTMS POSSIBLE ON THE NEAR SHORE WATERS LATE SUN. SUNDAY NIGHT AND MONDAY...MODERATE CONFIDENCE. S-SW WINDS GUSTING UP TO 20 KT WITH SEAS AROUND 5 FT MAINLY ON THE SOUTHERN OUTER WATERS. MAY SEE PATCHY FOG DEVELOP LATE SUN NIGHT INTO MON MORNING. TUESDAY...MODERATE CONFIDENCE. EXPECT SW WINDS BELOW SMALL CRAFT CRITERIA ALONG WITH SEAS BELOW 5 FT. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE.
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&& $$ SYNOPSIS...WTB/EVT NEAR TERM...NOCERA SHORT TERM...WTB LONG TERM...EVT AVIATION...NOCERA/EVT MARINE...WTB/NOCERA/EVT

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