Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 310159 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 959 PM EDT MON MAR 30 2015 .SYNOPSIS... A QUIET NIGHT OF WEATHER PRIOR TO A CLIPPER-LOW SWEEPING SOUTH OF THE REGION BRINGING A MIX OF RAIN AND SNOW TO SOUTHERN-MOST PORTIONS OF NEW ENGLAND. WARMER TEMPERATURES TOWARDS THE END OF THIS WEEK THEN A MORE SIGNIFICANT STORM MAY APPROACH LATE THIS WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 10 PM UPDATE... MAY SEE A FEW OF THE REMNANT SHRA/SHSN ASSOCIATED WITH THE COLD FRONT STILL JUST TO THE W SPILL INTO THE E SLOPES OF THE BERKSHIRES AND PORTIONS OF THE CT VALLEY UNTIL MAINLY ABOUT 1 AM. AT WHICH POINT DRIER AIR AND THE LACK OF ADDITIONAL SUPPORT SHOULD BRING MOST OF THESE TO AN END. FORECAST ON TRACK OTHERWISE. MAIN ADJUSTMENTS ARE TO BRING POPS UP TO PEED WITH THIS THINKING. PREVIOUS DISCUSSION... QUIET WEATHER. SCATTERED RAIN / SNOW SHOWERS CONCLUDE WITH ONLY REMNANT MID- TO HIGH-LEVEL CLOUDS REMAINING. BREEZY W-WINDS WITH THE POTENTIAL FOR GUSTS UP TO 25 MPH. COLD AIR ADVECTION IN WAKE OF THE FRONT WHICH WILL SWEEP ACROSS THE REGION INTO THIS EVENING. EXPECT OVERNIGHT LOWS TO DROP TO AROUND THE LOW-30S...NEAR- SEASONABLE FOR THIS TIME OF YEAR. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... TUESDAY INTO TUESDAY NIGHT... DEPENDENCE OF THE FORECAST UPON THE TRACK OF THE CLIPPER DISTURBANCE THROUGH THE BASE OF THE BROADER CYCLONIC FLOW AND ITS SURFACE LOW PRESSURE REFLECTION IN AREAS OF FAVORABLE BAROCLINICITY / THERMAL PACKING. THE CLOSER TO THE S NEW ENGLAND SHORELINE...THE GREATER THE IMPACT. WENT WITH A CONSENSUS BLEND OF THE FORECAST GUIDANCE NOTING THE EC / NAM ALONG THE N-END OF THE ENVELOP WITH ALL OTHER FORECAST GUIDANCE SUGGESTING A SWING AND A MISS. FORECAST GUIDANCE CONSENSUS HAS CLIPPER LOW TRACK OFF THE DELMARVA COAST ALONG A W-E ZONAL-FLOW. OVER-RUNNING PRECIPITATION APPEARS LARGELY ABSENT THOUGH W-E SETUP...DISCREET OUTCOMES APPARENT WITH FRONTOGENETICAL BANDING ALONG THE PARENT WARM FRONT TO THE CLIPPER LOW AROUND H7-8. IN ADDITION BETTER MOISTURE AND QG-FORCING MAINTAIN S OF NEW ENGLAND PARENT WITH THE LOW WITH CONSENSUS OF GUIDANCE. SO FEEL THE BULK OF PRECIPITATION WILL REMAIN OFFSHORE. ANY ACTIVITY WILL BE LIGHT MOSTLY S OF THE MASS-PIKE. SUBSEQUENTLY WITH DRY LOW- LEVELS AT ONSET FEEL WETBULBING / DYNAMIC COOLING OF LOW-LEVELS WILL BE MINIMAL AGAINST HIGHS THAT ARE FORECAST TO WARM INTO THE LOW- TO MID-40S WITH DAYTIME HEATING PRIOR TO THE ONSET OF THE STORM WHICH IS EXPECTED TO BE LATE. YET PROCEEDING INTO A EVENING ALONG WITH AN ISALLOBARIC RESPONSE OF WINDS THAT WILL FUNNEL OUT OF THE N ABSENT OF ARCTIC HIGH PRESSURE...FEEL PRECIP-TYPE WILL VARY BETWEEN RAIN / SNOW FROM WHICH AM NOT EXPECTING MUCH IN THE WAY OF ACCUMULATION. IF ANY...A TRACE AT MOST ON LINGERING SNOWPACK / ELEVATED SURFACES. GREATEST IMPACTS WILL BE ALONG THE IMMEDIATE S-COAST AND ISLANDS. MAJORITY OF THE IMPACTS WILL BE DUE TO VISIBILITY RESTRICTIONS WITH SNOW...IF ANYTHING. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... HIGHLIGHTS... * MODERATING MORE SPRING-LIKE TEMPS LATE THIS WEEK * INCREASING CHANCES FOR PRECIP LATE THIS WEEK INTO THE WEEKEND DISCUSSION... MODELS ARE IN GOOD AGREEMENT ON THE BROAD SCALE WITH SOME EXPECTED DETAIL DIFFERENCES THROUGHOUT THE LONG TERM. A SERIES OF SHORTWAVES WILL MOVE ACROSS THE NORTHEAST CONUS WITH ATTENDANT SURFACE LOW PRESSURE CENTERS/COLD FRONTS MOVING OVER SOUTHERN NEW ENGLAND. THIS WILL BRING SEVERAL CHANCES OF RAIN TO THE REGION THROUGHOUT THE LONG TERM PERIOD OF THE FORECAST. WEDNESDAY...HIGH PRESSURE BUILDS OVER SOUTHERN NEW ENGLAND BRINGING DRY WEATHER AND COOLER TEMPERATURES. EXPECT BELOW NORMAL TEMPERATURES. THURSDAY...TEMPERATURES BEGIN TO MODERATE AS HIGH PRESSURE MOVES OFFSHORE AND LOW PRESSURE MOVES INTO QUEBEC. TEMPERATURES WILL REMAIN BELOW NORMAL BUT ONLY BY A FEW DEGREES. EXCELLENT MIXING... COUPLED WITH A STRONG LOW LEVEL JET WILL LIKELY RESULT IN GUSTY WINDS. THURSDAY NIGHT THROUGH SATURDAY...TWO SHORTWAVE TROUGHS AND THEIR ATTENDANT LOW PRESSURE SYSTEMS WILL MOVE OVER THE NORTHEASTERN UNITED STATES...BRINGING A WIDESPREAD RAINFALL TO SOUTHERN NEW ENGLAND. AT THIS POINT...LOOKING AT MAINLY RAIN SHOWERS WITH AROUND AN INCH OF QPF. THERE ARE STILL DETAIL DIFFERENCES IN THE MODELS FOR THIS PERIOD SO QPF AMOUNTS ARE LIKELY TO CHANGE. WARMEST DAY OF THE WEEK SHOULD BE FRIDAY WHEN THEY WILL ACTUALLY CLIMB ABOVE NORMAL...POSSIBLY GIVING US OUR FIRST 60+ DEGREE DAY OF THE SPRING. TEMPERATURES FALL SATURDAY...DROPPING BACK BELOW NORMAL BEHIND THE COLD FRONT THAT TRAILS THE LAST LOW PRESSURE SYSTEM. SUNDAY...HIGH PRESSURE BUILDS IN WITH DRY WEATHER AND TEMPERATURES WELL BELOW NORMAL FOR EARLY APRIL. MONDAY...ANOTHER CHANCE OF RAIN AS LOW PRESSURE MOVES INTO THE GREAT LAKES...PUSHING HIGH PRESSURE OFFSHORE. TEMPERATURES BEGIN TO MODERATE ONCE AGAIN...CREEPING BACK TOWARDS NORMAL. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM /THROUGH TUESDAY NIGHT/...HIGH CONFIDENCE. 00Z UPDATE... LINGERING SCT -SHRA/-SHSN CONCLUDING TOWARDS 02Z. VFR. COLD FRONT SWEEPS ACROSS THE TERMINALS LATE INTO THE EVENING HOURS BEHIND WHICH WINDS VEER W/NW. GUSTS UP TO 25 KTS. TUESDAY INTO TUESDAY NIGHT... STORM SWEEPING S OF NEW ENGLAND. LOWEST CONDITIONS ACROSS S-MOST NEW ENGLAND WITH POTENTIAL IFR WITH -SN. OTHERWISE LOW-END VFR / MVFR CIGS AND VSBYS MOSTLY S OF THE CT-RI-MA BORDER. N/NW WINDS INCREASING LATE WITH GUSTS UP TO 25 KTS FOR COASTAL TERMINALS. KBOS TAF...GUSTY W-WINDS OVERNIGHT. KBDL TAF...QUIET WEATHER PERIOD. OUTLOOK...WEDNESDAY THROUGH SATURDAY... WEDNESDAY AND THURSDAY...HIGH CONFIDENCE. VFR. GUSTY SOUTHWESTERLY WINDS ARE POSSIBLE THURSDAY. THURSDAY NIGHT THROUGH SATURDAY...MODERATE CONFIDENCE. MVFR CONDITIONS ARE LIKELY IN RAIN SHOWERS. IFR CONDITIONS ARE POSSIBLE FRIDAY NIGHT IN FOG. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM /TODAY THROUGH TUESDAY/...HIGH CONFIDENCE. COLD FRONT SWEEPING THE WATERS DURING THE EVENING HRS. SW-WINDS BACKING NW DURING WHICH TIME GUSTS UP TO 25 KTS WILL BE POSSIBLE. SEAS ABOVE 5 FEET MAINLY ON THE OUTER WATERS...THOUGH COULD BE SOME LINGERING ISSUES FOR RI / BI SOUND. TUESDAY INTO TUESDAY NIGHT... 10 PM UPDATE... HAVE EXTENDED TIMING OF E INTRA-COASTAL WATERS SMALL CRAFT ADVISORIES AS RECENT TREND SUGGESTS STRONGER WIND GUSTS WITH THE FROPA LATER TONIGHT INTO TOMORROW MORNING. WENT THROUGH 12Z FOR NOW TO ALLOW FOR BETTER ASSESSMENT OF OVERNIGHT MODEL TRENDS. ALSO...WILL BE ADDING NARRAGANSETT BAY AND BOSTON HARBOR WITH THIS UPDATE. PREVIOUS DISCUSSION... STORM SYSTEM SWEEPS S OF NEW ENGLAND. N/NW FLOW...WHICH WILL INCREASE TOWARDS THE LATER HALF OF THE PERIOD. WILL BE A LULL IN WIND AND WAVE ACTION DURING WHICH TIME A RAIN / SNOW MIX WILL BE AN ISSUE MOSTLY FOR THE S-WATERS WITH POTENTIAL VISIBILITY IMPACT. THEN WAVES INCREASE IN EXCESS OF 5-FEET WITH ENHANCING N/NW-FLOW. SMALL-CRAFT HEADLINES CONTINUE FOR THE OUTER WATERS THROUGHOUT THE FORECAST PERIOD...WHILE INNER-WATERS EXPIRE OVERNIGHT. OUTLOOK...WEDNESDAY THROUGH SATURDAY... WEDNESDAY AND THURSDAY...SEAS DIMINISH AS HIGH PRESSURE BUILDS OVER THE WATERS. NORTHWESTERLY WINDS SHIFT TO THE SOUTHWEST DIMINISHING THROUGH THE PERIOD. OCCASIONAL 25 KT GUSTS ARE POSSIBLE ON THE OUTER WATERS AT TIMES. THURSDAY NIGHT THROUGH SATURDAY...SEAS INCREASE AS TWO SEPARATE LOW PRESSURE CENTERS AND THEIR COLD FRONTS APPROACH THE WATERS. SOUTHWESTERLY WINDS 15 TO 20 KTS SHIFT TO THE NORTHWEST SATURDAY MORNING. GUSTS UP TO 30 KTS ARE POSSIBLE AT TIMES. SMALL CRAFT ADVISORIES ARE LIKELY FOR BOTH WINDS AND SEAS AT LEAST ON THE OUTER WATERS...IF NOT ON THE INTERIOR BAYS AND SOUNDS AT TIMES. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR ANZ230>234-236- 251. SMALL CRAFT ADVISORY UNTIL 2 PM EDT TUESDAY FOR ANZ235-237. SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR ANZ250-254-255. SMALL CRAFT ADVISORY UNTIL 5 PM EDT TUESDAY FOR ANZ256. && $$ SYNOPSIS...RLG/SIPPRELL NEAR TERM...DOODY/SIPPRELL SHORT TERM...SIPPRELL LONG TERM...RLG AVIATION...RLG/SIPPRELL MARINE...RLG/SIPPRELL

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