Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 012322 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 722 PM EDT WED APR 1 2015 .SYNOPSIS... HIGH PRESSURE AND CHILLY OVERNIGHT. TURNING MILDER INTO THURSDAY WITH BREEZY SOUTHWEST WINDS. RAIN CHANCES INCREASE TOWARDS FRIDAY MORNING WITH THE THREAT OF HEAVY RAIN AND THUNDERSTORMS AS WAVES OF LOW PRESSURE SLIDE ACROSS A SLOW MOVING COLD FRONT. DRY AND CHILLIER WEATHER FOLLOWS BY LATE SATURDAY INTO SATURDAY NIGHT. FAST MOVING LOW PRESSURE MAY BRING A FEW RAIN AND/OR SNOW SHOWERS TO THE REGION SUNDAY INTO SUNDAY NIGHT. PERIODS OF UNSETTLED WEATHER POSSIBLE FOR THE FIRST HALF OF NEXT WEEK...BUT CONFIDENCE IS QUITE LOW. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 730 PM UPDATE...MADE ADJUSTMENTS TO THE TEMPERATURES AND DEWPOINTS TO BRING THEM BACK IN LINE WITH CURRENT TRENDS. OTHERWISE...THE FORECAST WAS ON TRACK. WINDS TAPER AS HIGH PRESSURE PUSHES INTO THE REGION. ANTICIPATE QUIET WEATHER CONSISTING OF MOSTLY CLEAR CONDITIONS AND LIGHT / VARIABLE WINDS. WHILE SOME INCREASING CLOUDS LATE...EXPECTING AN OPPORTUNITY FOR RADIATIONAL COOLING. A CONSENSUS BLEND OF MOS GUIDANCE...NUDGED TEMPERATURES DOWN A FEW DEGREES FOR AREAS WHICH NOTORIOUSLY RADIATE OUT AND VALLEY LOCATIONS SUBJECT TO COLD-AIR DRAINAGE /KATABATIC FLOW/. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... */ THURSDAY... WARM FRONT LIFTING NE ACROSS THE REGION ALONG THE NOSE OF RETURN WARM-MOIST SW-FLOW ALONG THE W-PERIPHERY OF THE LOW- TO MID-LEVEL RIDGE AXIS PUSHING E. WITH MID- TO UPPER-LEVEL SUPPORT LACKING... FEEL A DRY FORECAST PREVAILS. THOUGH THERE IS SOME HINT OF LOW- TOPPED SHOWERY WEATHER THE BETTER CHANCES OF WHICH ARE ALONG THE W- SLOPES OF HIGHER TERRAIN...SYNOPTIC FORCING AND DYNAMICS ARE LARGELY ABSENT...MAINLY FOUND NW ACROSS CANADA. ONSHORE FLOW INCREASING OUT OF THE S IN RESPONSE TO AN ENHANCING PRESSURE-GRADIENT WITH THE APPROACHING LOW AND HIGH PRESSURE PUSHING OFFSHORE. INCREASING SW-FLOW ALOFT BENEATH AN ANTICIPATED BOUNDARY- LAYER INVERSION AT H85 TEMPERATURES WARM TO +6-8C WITH H925 +2-4C. BUT WITH CLOUDS REMAINING A NUISANCE MAINLY OVER THE N/W OF NEW ENGLAND...WHEREAS S/E REMAIN MOSTLY CLEAR...THE HIGH-ANGLE OF THE EARLY APRIL SUN WILL LIKELY ALLOW FOR HIGHS UP AROUND THE LOW- TO MID-50S. THE WARM-SPOTS LIKELY IN THE LOWER CT-VALLEY...MERRIMACK RIVER VALLEY...AND INTERIOR E/SE MA. COOLER ALONG THE S-SHORE AND OUT ON CAPE COD WITH THE ONSHORE SW-FLOW OFF THE MUCH COOLER WATERS. */ THURSDAY NIGHT... FRONTAL BOUNDARY SWEEPS S ACROSS NEW ENGLAND TOWARDS FRIDAY MORNING. NEARLY PARALLEL FLOW ALONG THE BOUNDARY. ATTENDANT SYNOPTIC FORCING AND DYNAMICS LACKING. THERE IS LITTLE INDICATION OF CONVERGENCE NOR DEEP-LAYER ASCENT. THOUGH ANOMALOUS PWATS ON THE ORDER OF +1-2 SD AS CONSENSUS FORECAST GUIDANCE SUGGESTS 1.00-1.25 INCHES...WITHOUT MUCH FORCING / LIFT...CAN NOT EFFICIENTLY GET THE ATMOSPHERE TO RAIN OUT. SO WHILE WET WEATHER IS LIKELY...EXPECT JUST SHOWERS. NO THUNDER AND NOTHING PRONOUNCED. SCATTERED ACTIVITY. NO FLOODING CONCERNS. JUST AN ABUNDANCE OF CLOUDS AND OVERALL A MILD NIGHT THE LIKES WE HAVE NOT SEEN SINCE THANKSGIVING 2014 FOR BOSTON / PROVIDENCE...SINCE LATE OCTOBER FOR HARTFORD / WORCESTER...USING 45 DEGREES AS THE THRESHOLD. AMAZING! LOOKING AT LOWS AROUND THE LOW- TO MID-40S. WILL NEED TO MONITOR CLOSELY FOR THE PRESENCE OF DENSE FOG. HIGHER DEWPOINT AIR OVER THE COLDER OCEAN...AND RELATIVELY COLDER GROUND WITH LINGERING SNOWPACK...WILL LIKELY RESULT IN THE DEVELOPMENT OF SOME DENSE FOG. THOUGH MILDER CONDITIONS USHERED BY BREEZY SW- FLOW. WILL THIS DETER FOG DEVELOPMENT REMAINS TO BE SEEN. OF SOME CERTAINTY WILL BE THE EXPECTATION OF BREEZY HIGH DEWPOINT AIR ALONG WITH WET-WEATHER WILL ALLOW FOR FASTER EROSION OF ANY LEFT- OVER SNOW. PERHAPS WE CAN FINALLY SAY GOODBYE TO THE REMNANTS OF WINTER. RIGHT NOW WE HAVE A FOG-FREE FORECAST AS NEITHER CLIMO NOR MOS-GUIDANCE SUGGESTS FOG MOSTLY DUE TO ANTICIPATED BREEZY WINDS. AGAIN...WILL JUST HAVE TO MONITOR. SW-GUSTS 25-35 MPH ACROSS S/SE COASTAL NEW ENGLAND...WITH 15-25 MPH GUSTS ACROSS THE INTERIOR. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... * QUITE UNSETTLED WEATHER EXPECTED THROUGH THE LONG TERM * HIGHEST CONFIDENCE IN PERIODS OF SHOWERS FRI INTO SAT AM * RAIN/SNOW SHOWERS POSSIBLE AGAIN SUN * LOW CONFIDENCE ON UNSETTLED WEATHER PATTERN NEXT WEEK MODELS ARE NOT IN VERY GOOD AGREEMENT AT ALL FOR MUCH OF THE FORECAST PERIOD. THE ECMWF IN PARTICULAR SEEMS TO BE SOMEWHAT OF AN OUTLIER. HOWEVER...CONFIDENCE IS RATHER LOW THROUGH THE PERIOD BUT ESPECIALLY NEXT WEEK. SOMEWHAT HIGHER CONFIDENCE IN THE FORECAST THROUGH SUNDAY...THOUGH THERE ARE STILL SOME MODEL DIFFERENCES THAT COULD YIELD DIFFERENT FORECAST RESULTS. FRIDAY THROUGH EARLY SATURDAY...A SHORTWAVE TROUGH AND ITS ATTENDANT LOW PRESSURE SYSTEM WILL MOVE OVER THE NORTHEASTERN UNITED STATES... BRINGING WIDESPREAD SHOWERS TO THE AREA. THE 01/12Z GFS/NAM BRING THIS LOW PRESSURE SYSTEM UP FROM THE LOWER MS VALLEY ARE THROUGH SOUTHERN NEW ENGLAND. THE 01/00Z ECMWF BRINGS THE LOW PRESSURE UP THROUGH NORTHERN NEW ENGLAND. THIS WOULD MEAN A DIFFERENCE IN TEMPERATURE PROFILES AS WELL AS WIND DIRECTIONS DURING THE DAY. HOWEVER...DON/T BELIEVE THERE IS A SIGNIFICANT ENOUGH DIFFERENCE TO RESULT IN A CHANGE OF PTYPE FROM RAIN. LEANING MORE TOWARDS THE GFS/NAM SOLUTION. WARMEST DAY OF THE WEEK SHOULD BE FRIDAY WHEN TEMPS WILL ACTUALLY REACH OR POSSIBLY EVEN CLIMB ABOVE NORMAL. THIS MAY RESULT IN A FEW LOCATIONS REACHING 60+ DEGREES FOR THE FIRST TIME THIS SPRING. REST OF SATURDAY...TEMPERATURES FALL BACK BELOW NORMAL BEHIND THE COLD FRONT THAT TRAILS THIS LOW PRESSURE SYSTEM. MUCH OF THE DAY SHOULD BE DRY PRIOR TO ANOTHER FRONT APPROACHING THE AREA. SUNDAY...A QUICK COLD FRONT WILL MOVE THROUGH THE REGION BRINGING ANOTHER ROUND OF RAIN AND POSSIBLY SNOW SHOWERS TO THE REGION. MONDAY THROUGH WEDNESDAY...A VERY UNSETTLED PATTERN WITH LOW CONFIDENCE IN THE DETAILS AND TIMING OF THE FORECAST. THERE IS POTENTIAL FOR RAIN SHOWERS EACH DAY IN ONE MODEL OR ANOTHER BUT NOT EXPECTING A WASHOUT ANY ONE DAY NOR THROUGH THE ENTIRE PERIOD. TEMPERATURES WILL BE FIGHTING BETWEEN COOLER AIR TO THE NORTH AND WARMER AIR TO THE SOUTH. GIVEN THE PATTERN AS OF LATE...EXPECT THE COOLER AIR WILL LIKELY WIN OUT. WILL GO WITH A BLEND OF MODEL GUIDANCE FOR THIS TIME PERIOD. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM /THROUGH THURSDAY NIGHT/... TONIGHT INTO THURSDAY...HIGH CONFIDENCE. VFR. VRB WINDS OVERNIGHT INCREASING OUT OF THE SW THROUGH THE DAY THURSDAY WITH GUSTS UP TO 25 KTS ALONG THE S-SHORE BY EVENING. SOME LOW-END VFR CIGS MAINLY ACROSS N/NW MA AROUND THURSDAY MORN INTO MIDDAY. THURSDAY NIGHT...MODERATE CONFIDENCE. LOW-END VFR / MVFR CIGS WITH SCT -SHRA. CONTINUED BLUSTERY SW-FLOW WITH GUSTS 15-20 KTS ACROSS MOST OF THE TERMINALS...25-30 KT OVER S/SE-COASTAL NEW ENGLAND. LOW CONFIDENCE AT THIS TIME...BUT DENSE IFR FOG POSSIBLE. LLWS LIKELY AS SW-WINDS AT 2 KFT WILL BE 40-50 KTS. KBOS TAF...HIGH CONFIDENCE. GUSTY PRESENTLY...BUT SHOULD SEE THESE GUSTS DROP OFF INTO EVENING. KBDL TAF...HIGH CONFIDENCE. GUSTY PRESENTLY...BUT SHOULD SEE THESE GUSTS DROP OFF INTO EVENING. .OUTLOOK...FRIDAY THROUGH MONDAY... FRIDAY THROUGH SATURDAY MORNING...MODERATE CONFIDENCE. MVFR CONDITIONS ARE LIKELY IN RAIN SHOWERS. IFR CONDITIONS ARE POSSIBLE FRIDAY NIGHT IN FOG. SATURDAY AFTERNOON AND NIGHT...MODERATE CONFIDENCE. MAINLY VFR. SUNDAY AND MONDAY...LOW CONFIDENCE. MAINLY VFR. PERIODS OF MVFR/IFR IN RA/SN SHOWERS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM /THROUGH THURSDAY NIGHT/... TONIGHT...HIGH CONFIDENCE. HIGH PRESSURE BUILDING ACROSS THE WATERS. WINDS BECOMING LIGHT AND VARIABLE. SEAS RELAX. THURSDAY...HIGH CONFIDENCE. WINDS INCREASING OUT OF THE SW THROUGH THE DAY WITH GUSTS UP TO 25 KTS ALONG THE S-SHORE BY EVENING. SWELL BUILDING RESULTING IN SEAS IN EXCESS OF 5-FEET BEGINNING BY AFTERNOON INTO EVENING. THURSDAY NIGHT...MODERATE CONFIDENCE. CONTINUED BLUSTERY SW-FLOW WITH GUSTS 25-30 KT OVER S/SE WATERS. LOW CONFIDENCE AT THIS TIME...BUT DENSE IFR FOG POSSIBLE. WINDS MAY LIMIT FOG DEVELOPMENT. WILL NEED TO CLOSELY MONITOR. LOW CONFIDENCE CONCERNING GALES BUT COULD NOT RULE OUT AN INTERMITTENT GALE-FORCE GUST AT TIMES. SEAS BUILDING 6-8 FEET ON THE OUTER WATERS...INCLUDING RI / BI SOUND. SHOWERY WEATHER...NOT THINKING ANY HEAVY RAIN / THUNDERSTORMS AT THIS TIME. .OUTLOOK...FRIDAY THROUGH MONDAY... FRIDAY THROUGH SATURDAY...SEAS INCREASE AS LOW PRESSURE APPROACHES AND THEN MOVES OVER 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 ON ALL THE WATERS WITH A LOW PROBABILITY OF GALES BEING NECESSARY FOR THE OUTER WATERS FOR A PERIOD SATURDAY. SATURDAY NIGHT THROUGH SUNDAY...SEAS DIMINISH...BUT REMAIN ABOVE 5 FEET ON THE OUTER WATERS. NORTHWESTERLY WINDS DIMINISH BUT REMAIN ABOVE 25 KTS FOR MOST OF THE WATERS. SMALL CRAFT ADVISORIES WILL LIKELY BE NECESSARY. MONDAY...SEAS FALL BELOW 5 FEET AS A BRIEF PERIOD OF HIGH PRESSURE BUILDS OVER THE WATERS. SOUTHWESTERLY WINDS CONTINUE TO DIMINISH AND SLOWLY SHIFT TO THE SOUTHEAST. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 2 PM THURSDAY TO 6 AM EDT FRIDAY FOR ANZ231>237-250-251-254>256. && $$ SYNOPSIS...RLG/SIPPRELL NEAR TERM...RLG/SIPPRELL SHORT TERM...SIPPRELL LONG TERM...RLG AVIATION...RLG/SIPPRELL MARINE...RLG/SIPPRELL

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