Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 261414 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1014 AM EDT TUE AUG 26 2014 .SYNOPSIS... HIGH PRESSURE OVER NEW ENGLAND WILL BRING WARM AND DRY WEATHER AS IT DRIFTS SOUTH OF THE AREA. A COLD FRONT THEN MOVES ACROSS NEW ENGLAND WEDNESDAY AND WEDNESDAY NIGHT BRINGING A CHANCE OF AN ISOLATED SHOWER OR THUNDERSTORM. HURRICANE CRISTOBAL WILL REMAIN WELL OFFSHORE AND TURN OUT TO SEA WEDNESDAY NIGHT...HOWEVER ROUGH SURF AND RIP CURRENTS WILL IMPACT OCEAN BEACHES WED AFTERNOON INTO FRI. DRY...COOLER CONDITIONS RETURN FOR THE LATTER PART OF THE WEEK. ANOTHER FRONT MAY BRING UNSETTLED CONDITIONS DURING THE HOLIDAY WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 10 AM UPDATE... ONLY CHANGE WAS TO INCREASE AFTERNOON TEMPS BY A FEW DEGS GIVEN THE WARM START TO THE DAY THAN YESTERDAY ALONG WITH THE AIRMASS OVER NEW ENGLAND SLIGHTLY WARMER THAN MON. 12Z CHH OBSERVED SOUNDING HAS 850 TEMPS AROUND +15C WITH BLYR MIXING UP TO ABOUT 800 MB. THUS HIGHS TODAY INLAND WILL RANGE FROM THE U80S TO L90S. CLOSER TO THE COAST TEMPS ARE TRICKY ESPECIALLY IN THE BOSTON TO PROVIDENCE CORRIDOR AS SSW GRADIENT MAY PRECLUDE MARITIME AIRMASS REACHING THIS AREA. THEREFORE MU80S ARE LIKELY FROM PROVIDENCE TO BOSTON WITH THEIR W-NW SUBURBS POSSIBLY TOUCHING 90...SUCH AS BROOKLINE/CAMBRIDGE AND POSSIBLY AS FAR EAST AS BACKBAY. STILL WARM AT THE BEACHES WITH HIGHS U70S TO L80S. AS OF 10 AM JUST ABOUT ALL THE RADIATIONAL FOG HAS BURNED OFF. EARLIER DISCUSSION BELOW. ================================================================= PREVIOUS DISCUSSION... HIGH PRESSURE REMAINS OVERHEAD TODAY AND WILL PROVIDE SUNNY DAY WITH LIGHT WINDS. THIS LIGHT FLOW WILL FAVOR THE RESUMPTION OF SEA BREEZES LATE THIS MORNING AND EARLY AFTERNOON. MIXING SHOULD REACH TO AT LEAST 850 MB WHERE TEMPS OF 15-16C SHOULD SUPPORT MAX TEMPS IN THE MID TO UPPER 80S...EVEN 90 IS POSSIBLE IN SOME NORMALLY WARM INLAND SPOTS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... TONIGHT... RIDGE SHIFTS OFFSHORE TONIGHT WITH THE PRESSURE GRADIENT STARTING TO FAVOR A SOUTHWEST FLOW. BUT THAT GRADIENT AND RESULTING FLOW SHOULD REMAIN LIGHT ENOUGH FOR ANOTHER ROUND OF PATCHY FOG OVERNIGHT. DEWPOINTS ARE EXPECTED IN THE LOW TO MID 60S...SO EXPECT MIN TEMPS IN THE 60S. WEDNESDAY... COLD FRONT DROPPING SOUTHEAST FROM NORTHERN ONTARIO WILL REACH NORTHERN NEW ENGLAND BY WEDNESDAY MORNING. MODEL CONSENSUS BRINGS FROPA TO SOUTHERN NEW ENGLAND DURING THE AFTERNOON AND EVENING. RH FIELDS LOOK LIMITED...BUT PRECIPITABLE WATER VALUES ARE FORECAST AROUND 1.5 INCHES SO THERE IS WATER TO BE UTILIZED. TOTALS WILL BE IN THE MID 40S. THE UPPER JET DRIVING THE SUPPORTING SHORTWAVE MOVES INTO POSITION OVER SOUTHERN NEW ENGLAND DURING THE TIME OF FROPA. SO WE HAVE QUESTIONS ON MOISTURE AND INSTABILITY BUT SUPPORTIVE DYNAMICS. WE WILL NUDGE POPS UP TO CHANCE LEVELS IN WESTERN MA/NORTHERN CT/NORTHERN RI WITH SLIGHT CHANCE POPS IN THE REMAINDER OF THE REGION. TEMPS AT 850 MB WILL BE A LITTLE WARMER...16-17C...BUT GREATER POTENTIAL FOR AFTERNOON CLOUDS MAY LIMIT HEATING/MIXING. COULD STILL REALIZE A FEW HIGHS APPROACHING 90 WITH SW FLOW IN PLACE...BUT WILL SEE HIGHS MAINLY IN THE 80S. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * COLD FRONT MOVES OFFSHORE WEDNESDAY NIGHT * COOL TO SEASONABLE CONDITIONS ARE EXPECTED UNDER HIGH PRESSURE THURSDAY AND FRIDAY * POTENTIAL FOR SHOWERS DURING THE LABOR DAY WEEKEND * HURRICANE CRISTOBAL WILL PASS WELL SE OF NANTUCKET WEDNESDAY NIGHT AND THURSDAY. EXPECT INCREASING SWELLS AND ROUGH SURF TO MOVE INTO S FACING COASTAL AREAS LATE WEDNESDAY THROUGH THURSDAY NIGHT. EXPECT AN ENHANCED RIP CURRENT RISK AS WELL. WEDNESDAY NIGHT...H5 SHORT WAVE WILL MOVE SE AND DIG AS IT APPROACHES THE REGION. HOWEVER...MOST OF THE ASSOCIATED ENERGY WILL REMAIN ACROSS NORTHERN NEW ENGLAND AS THE SURFACE FRONT CONTINUES TO PUSH OFFSHORE. CAN NOT TOTALLY RULE OUT SCT SHOWERS OR AN ISOLD THUNDERSTORM THROUGH MIDNIGHT...THEN ANY LEFTOVER SHOWERS WILL MOVE OFF THE S COAST OVERNIGHT WITH LIGHT NW WINDS BRINGING COOLER AND DRIER AIR. THURSDAY THROUGH FRIDAY...MID AND UPPER LEVEL RIDGE BUILDS ACROSS THE GREAT LAKES N INTO HUDSON BAY DURING THURSDAY...WITH DOWNSTREAM NW FLOW BRINGING DRY AND SEASONABLE CONDITIONS AS LARGE SURFACE HIGH SLOWLY BUILDS E. NW WINDS MAY BECOME GUSTY...UP TO AROUND 20 KT... MAINLY ACROSS THE INTERIOR WITH EXCELLENT MIXING IN PLACE. EXPECT DAYTIME HIGHS IN THE 70S...WITH A FEW LOCALES REACHING 80. WITH MOSTLY CLEAR SKIES THU NIGHT...EXPECT TEMPS TO FALL BACK TO THE 50S...WITH A FEW OF THE COOLER INLAND SPOTS ACROSS S NH/N CENTRAL AND W MA POSSIBLY DROPPING BELOW 50. AS THE HIGH BUILDS SLOWLY E ACROSS NORTHERN NEW ENGLAND DURING FRIDAY...EXPECT WINDS TO SHIFT TO E-NE BY MIDDAY OR EARLY AFTERNOON ON FRIDAY THEN VEER TO SE LATE IN THE DAY. THIS WILL BRING COOLER AIR OFF THE OCEAN...SO TEMPS WILL BE A FEW DEGS COOLER THAN THURSDAY. EXPECT HIGHS IN THE LOWER-MID 70S...MAYBE A FEW DEGS WARMER IN THE MID AND LOWER CT VALLEY. SATURDAY THROUGH LABOR DAY...HIGH PRES WILL BUILD OFFSHORE DURING SATURDAY. EXPECTING UPPER LEVEL FLOW ACROSS THE NORTHERN TIER TO FLATTEN OUT...WHICH WILL ALLOW THE NEXT FRONT TO APPROACH. LONG RANGE MODELS ACTUALLY SEEM TO BE IN FAIRLY GOOD AGREEMENT IN BRINGING A COLD FRONT IN THE FLOW...BUT WILL THE FRONT WILL TEND TO BECOME PARALLEL TO THE FLOW LATER SAT/SAT NIGHT. BIG QUESTION AT THIS POINT WILL BE WHERE THE FRONT WILL SET UP. AT THIS POINT... HAVE KEPT SLIGHT CHANCE TO CHANCE POPS GOING OFF AND ON THROUGH THE WEEKEND. THINK THAT SAT WILL BE THE DRIER OF THE THREE DAY WEEKEND...THOUGH SHOWERS AND EVEN AN ISOLD TSTM MAY SNEAK INTO SW NH/NW MA LATE IN THE DAY. BOTH SUNDAY AND MONDAY LOOK QUESTIONABLE WITH SCT SHOWERS. ISOLD TSTMS ARE POSSIBLE DURING EACH AFTERNOON/EARLY EVENING. WITH A GENERAL S-SW FLOW IN PLACE...TEMPS WILL REBOUND TO AROUND 80 BUT HUMIDITY WILL ALSO BE INCREASING. TIMING AND PLACEMENT OF THE FRONT ARE IN QUESTION SO LOWER CONFIDENCE ON THIS PORTION OF THE FORECAST. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. 10 AM UPDATE... SHORT TERM...THIS AFTERNOON THROUGH WEDNESDAY...HIGH CONFIDENCE. TODAY...VFR. DEVELOPING SEA BREEZES LATE MORNING AND EARLY AFTERNOON ON ALL COASTS. TONIGHT...VFR. SEA BREEZES SHOULD DISSIPATE AROUND OR JUST AFTER SUNSET. PATCHES OF IFR IN FOG SHOULD DEVELOP AGAIN AFTER MIDNIGHT. WEDNESDAY...VFR MOST OF THE TIME. PATCHY IFR IN FOG POSSIBLY FIRST THING IN THE MORNING. CLOUDS DEVELOP AT 4000-6000 FEET IN THE LATE MORNING AND AFTERNOON. COLD FRONT MOVES ACROSS THE REGION DURING THE MID TO LATE AFTERNOON WITH POTENTIAL FOR SCATTERED TO WIDELY- SCATTERED MVFR IN AFTERNOON SHOWERS/TSTMS. KBOS TERMINAL...HIGH CONFIDENCE IN TAF WITH SLIGHTLY LOWER CONFIDENCE ON SEA BREEZE AS PRESSURE GRADIENT MAY BE SUFFICIENT TO SHIFT WINDS TO 200 DEGS. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WEDNESDAY NIGHT...MODERATE CONFIDENCE. VFR. LOW PROB OF WIDELY SCT SHOWERS EARLY...THEN CLEARING SKIES. THURSDAY INTO FRIDAY NIGHT...MODERATE CONFIDENCE. VFR. EXPECT NW WINDS GUSTING UP TO AROUND 20 KT DURING THU...THEN LIGHT E-SE WINDS ON FRI. LOW PROB OF PATCHY FOG WITH BRIEF MVFR VSBYS DURING PRE DAWN HOURS FRI. SATURDAY...MODERATE CONFIDENCE. MAINLY VFR. POTENTIAL FOR MVFR IN SCATTERED SHRA/ISOLATED TSRA ACROSS SW NH/W AND N CENTRAL MA LATE SAT/SAT NIGHT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM...TODAY THROUGH WEDNESDAY...HIGH CONFIDENCE. TODAY AND TONIGHT... EAST SWELLS OF 2-3 FT CONTINUE ACROSS THE WATERS. HIGH PRESSURE OVER NEW ENGLAND MOVES OVER THE WATERS TONIGHT MAINTAINING LIGHT WIND. VSBY MAY BRIEFLY LOWER IN FOG NEAR SHORE EARLY THIS MORNING AND AGAIN TONIGHT...OTHERWISE GOOD VSBY SHOULD PREVAIL ALONG WITH DRY WEATHER. WEDNESDAY... EAST SWELL SHIFTS TO A SOUTH SWELL BY AFTERNOON WITH VALUES REACHING 4-5 FEET ON THE SOUTHERN WATERS TOWARD SUNSET. A COLD FRONT FROM NORTHERN NEW ENGLAND WILL SWEEP ACROSS SOUTHERN NEW ENGLAND DURING THE AFTERNOON AND EVENING AND MAY GENERATE SCATTERED SHOWERS/THUNDERSTORMS THAT REACH THE COAST LATE IN THE DAY. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WEDNESDAY NIGHT AND THURSDAY...MODERATE CONFIDENCE. EXPECT COLD FRONT TO PUSH OFFSHORE WED NIGHT. WIDELY SCT SHOWERS/ISOLD THUNDER EARLY WED NIGHT POSSIBLE AS COLD FRONT MOVES OFFSHORE. EXPECT NW WINDS TO PICK UP ON THU...MAY GUST TO AROUND 20 KT ON THE NEAR SHORE WATERS. HRCN CRISTOBAL REMAINS WELL OFFSHORE AS IT HEADS INTO THE NORTHERN ATLC. INCREASING S-SE SWELLS MAY RESULT IN WAVE HEIGHTS UP TO 7 OR EVEN 8 FT ON THE OUTER WATERS. FRIDAY AND SATURDAY...MODERATE CONFIDENCE. DIMINISHING SWELL EXPECTED ON FRI WITH HIGH PRESSURE OVER THE WATERS. SEAS SHOULD SUBSIDE TO 5 FEET...BUT A LOW CHANCE THAT ROUGH SEAS MAY LINGER. WINDS BECOME S-SW AND STRENGTHEN ON SATURDAY BUT SHOULD REMAIN BELOW SMALL CRAFT CRITERIA FOR THAT TIMEFRAME. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...WTB/EVT NEAR TERM...WTB/NOCERA/EVT SHORT TERM...WTB LONG TERM...EVT AVIATION...WTB/NOCERA/EVT MARINE...WTB/EVT

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