Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 192036 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 336 PM EST WED NOV 19 2014 .SYNOPSIS...
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HIGH PRESSURE OVER THE REGION MOVES EAST TONIGHT...THEN A WEAK DISTURBANCE MAY BRING A FEW SNOW SHOWERS TO THE SOUTH COAST TONIGHT. ANOTHER SHOT OF UNSEASONABLY COLD AIR IS EXPECTED THURSDAY NIGHT INTO SATURDAY. A SIGNIFICANT WARM-UP IS IN STORE BY SUNDAY INTO EARLY NEXT WEEK. A STORM MOVING OUT OF TEXAS WILL LIKELY BRING RAIN TO SOUTHERN NEW ENGLAND SUNDAY NIGHT INTO EARLY NEXT WEEK.
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&& .NEAR TERM /THROUGH TONIGHT/...
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THROUGH 7 PM/00Z HIGH PRESSURE RIDGE AXIS IS OVERHEAD AND SHIFTING EAST. THE LEADING EDGE OF WARM ADVECTION CLOUDS IS MOVING ACROSS WESTERN NY AND WESTERN/CENTRAL PA. THESE CLOUDS EXTRAPOLATE TO THE HUDSON VALLEY BY 7 PM. THERE MAY BE A FEW HIGH CLOUDS OUT AHEAD OF THIS. WE/RE ALSO WATCHING CLOUD BANDS OVER THE OCEAN THAT ARE SOUTH OF THE ISLANDS. THE BANDS ARE ORIENTED WEST-EAST...BUT AS THE RIDGE AXIS SHIFTS EAST THE MOTIVATING FLOW WILL BECOME MORE SOUTHWEST- NORTHEAST AND SHOULD EVENTUALLY TURN THESE BANDS TOWARD THE CAPE AND ISLANDS AND POSSIBLY A LITTLE FARTHER WEST ALONG THE SOUTH COAST. TONIGHT... THE TWO CLOUD AREAS APPROACHING THIS EVENING WILL MOVE ACROSS SOUTHERN NEW ENGLAND TONIGHT. THE OCEAN CLOUD BANDS WILL MOVE UP ACROSS THE CAPE AND ISLANDS EARLY TONIGHT. MEANWHILE EXTRAPOLATION WOULD BRING CLOUDS IN FROM THE WEST AROUND 9-10 PM /02Z-03Z. THE SURFACE LOW WILL MOVE FROM THE GREAT LAKES OVER CANADA...PASSING TO OUR NORTH. THIS INCREASES THE PRESSURE GRADIENT SURFACE AND ALOFT AND BRINGS INCREASING SOUTHWEST WINDS. A 40 TO 50 KNOT LOW LEVEL JET WILL ENTER NEW ENGLAND AROUND MIDNIGHT AND REMAIN OVERHEAD THROUGH THE NIGHT. THE BEST JET DYNAMICS WILL REMAIN TO OUR WEST AND NORTH. SO ANY PCPN DIRECTLY CONNECTED TO THE CLIPPER LOW WILL BE LIGHT AND MOSTLY TO OUR NORTH. THE SOUTHWEST FLOW OFF THE OCEAN WILL BRING GREATER INSTABILITY INTO THE SOUTH COAST AREA...TOTAL TOTALS ARE FORECAST IN THE MID 40S WHICH WOULD SUPPORT SCATTERED RAIN/SNOW SHOWERS. SO THE FORECAST WILL BRING INCREASING CLOUDS...CHANCE POPS OVER THE CAPE/ISLANDS/SOUTH COAST...AND INCREASING WIND OVER THE OCEAN AND ALONG COASTAL AREAS. FOR MIN TEMPS WE STAYED CLOSE TO GUIDENCE WITH VALUES IN THE 20S INLAND AND LOW TO MID 30S CAPE/ISLANDS.
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&& .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
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THURSDAY... THE CLIPPER PASSES NORTH OF US DURING THE DAY AND SWINGS A COLD FRONT THROUGH THE REGION. WE MAY START OUT WITH SOME CLOUDS AS THE FRONT MOVES THROUGH BUT SHOULD SEE CLEARING FROM WEST TO EAST DURING THE DAY. SUNSHINE WILL PROMOTE MIXING UP TO 850 MB AND DRAW SOME OF THAT WIND TO THE SURFACE OVER LAND. THE 40 KNOT WINDS AT 850 MB FIRST THING IN THE MORNING WILL DIMINISH TO 25-30 KNOTS INLAND...BUT MAY LINGER OVER THE CAPE AND ISLANDS. THE WINDS THAT ARE THERE AROUND MIDDAY WILL BE MIXED TO THE SURFACE IN GUSTS. WE USED 25 KNOTS NORTHWEST TO 35 KNOTS CAPE AND ISLANDS. TEMPERATURES INITIALLY IN THE MIXED LAYER WOULD SUPPORT SFC MAX TEMPS IN THE 40S. BUT COLD ADVECTION FROM THE WEST WILL LOWER THESE VALUES IN THE AFTERNOON SO MAX TEMPS SHOULD BE MORE LIKE 35 TO 45...COLDEST NORTHWEST. THURSDAY NIGHT... HIGH PRESSURE OVER THE PLAINS AND LOW PRESSURE OVER THE MARITIMES WILL FAVOR WEST WINDS...BUT THE GRADIENT WILL BE DIMINISHING AND SO THE WINDS WILL ALSO DIMINISH. A SHORTWAVE MOVES OVERHEAD AND MAY SUPPORT A FEW CLOUDS ESPECIALLY NORTH OF THE MASS PIKE. BUT THE AIRMASS WILL BE DRY SO SKY COVER WILL BE LIMITED. THE COLDEST TEMPS AND CONTOUR HEIGHTS WILL MOVE IN THURSDAY NIGHT...SO TEMPS WILL BE A FEW DEGREES COOLER THAN TONIGHT. WE USED UPPER TEENS TO MID 20S.
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&& .LONG TERM /FRIDAY THROUGH WEDNESDAY/...
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HIGHLIGHTS... * ANOMALOUS COLD THROUGH SATURDAY * WARMER SUNDAY THROUGH END OF PERIOD * MAINLY RAIN LIKELY MONDAY OVERVIEW AND MODEL PREFERENCES... OPERATIONAL MODELS CONTINUE TO SHOW REASONABLY GOOD AGREEMENT THROUGH THE LONG TERM. THE LONGWAVE TROF ACROSS THE REGION WILL BEGIN A SLOW LIFT TOWARD THE EAST NORTHEAST AS INCOMING PACIFIC TROF FORCES RIDGE TO THE E. THIS PATTERN SHIFT IS WELL CAPTURED BY BOTH OPERATIONAL RUNS AND ENSEMBLES ALIKE...SO CONFIDENCE REMAINS RELATIVELY HIGH THAT A TRANSITION FROM BELOW NORMAL TEMPERATURES TO POSSIBLY EVEN ABOVE NORMAL IS EXPECTED OVER THE WEEKEND. WHILE THERE ARE SOME SLIGHT DIFFERENCES REGARDING THIS WAVE AND IT/S ATTENDANT COLD FRONT FOR SUN-MON...EVEN HERE A BLEND OF GUIDANCE CAPTURES THE PATTERN WELL. SUGGESTING A WARM INSIDE RUNNER. GIVEN THIS AGREEMENT...A GENERAL BLEND WILL BE USED FOR THIS UPDATE INCLUDING THE GFS/ECMWF AND SOME OF THE PREVIOUS FORECASTER. DETAILS... FRIDAY INTO FRI NIGHT... ONE MORE REINFORCING SHOT OF COLD AIR EXPECTED EARLY FRI IN THE FORM OF A MODEST ARCTIC FRONT ATTENDANT TO THE KICKER WAVE WHICH WILL SHIFT THE PATTERN E. THEREFORE...FOR THIS PERIOD...EXPECT CONTINUED BELOW NORMAL TEMPERATURES. THE FRONT WILL ALSO INTRODUCE YET ANOTHER ROUND OF GUSTY W-NW WINDS YIELDING BLUSTERY CONDITIONS. SOUNDINGS LOOK MAINLY DRY...SO EXPECT MAINLY JUST SOME CLOUDS WITH THIS FRONTAL PASSAGE. SAT AND SUN... UPPER LVL SHIFT AS CUTOFF/LONGWAVE TROF SHIFTS TO THE E ALLOWING STACKED RETURN FLOW WITH GULF REGION CONNECTIONS. THEREFORE...AFTER A COOL START ON SAT...EXPECT TEMPS TO GRADUALLY INCREASE THROUGH SUN. WARM FRONT WILL BE APPROACHING AS OCCLUDING SYSTEM MOVES INTO THE GREAT LAKES REGION. AT THIS TIME...HANGING LOW-MID LVL RIDGE SHOULD KEEP MOST OF SRN NEW ENGLAND DRY WITH THE BULK OF OVERRUNING PRECIP ACROSS NRN NEW ENGLAND UNTIL COLD FRONTAL/OCCLUSION PRECIP APPROACHES LATE IN THE DAY. H85 TEMPS ON SUN SUGGEST HIGHS MAY ACTUALLY BE ABOVE NORMAL BY SUN IN SPITE OF INCREASING CLOUD COVER AND OVERALL COLUMN MOISTURE. SUN NIGHT INTO MON... WHAT LOOKS LIKE A WARM OCCLUSION WILL MOVE ACROSS THE REGION LATE SUN NIGHT INTO EARLY MON. DYNAMICS ARE FAIRLY ROBUST HERE...WITH POTENTIAL FOR 60 KT H85 LLJ. COMBINE THIS WITH 1.25 INCH PWATS /NEARLY 3 STD DEV ABOVE NORMAL/ AND SETUP SUGGESTS POTENTIAL FOR HEAVY RAIN WITH MODEST CONVECTIVE ELEMENTS. INDEED THE COLUMN LOOKS TO BE WARM ENOUGH FOR ALL RAIN BY THE TIME THIS PRECIP BEGINS. GIVEN THE STRONG DYNAMIC POTENTIAL FOR THIS SYSTEM...WILL HAVE TO MONITOR FOR PRECIP/WIND HEADLINES. A SECONDARY LOW PRES MAY ATTEMPT TO MAKE A NORTHWEST PASS ON MON...CONTINUING THE UNSETTELD WX...BUT THERE ARE SOME DISCREPANCIES REGARDING THE MOISTURE BY THIS POINT. TUE INTO WED... ALTHOUGH ANOTHER /ALBEIT LESS DEEP OR COLD/ TROF WILL ATTEMPT TO SETTLE ACROSS THE NRN CONUS INTO THE GREAT LAKES...A BLOCKING PATTERN SUGGESTS THE CORE OF THE COLD AIR MAY REMAIN TO THE W AT THIS TIME.
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&& .AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...HIGH CONFIDENCE. TONIGHT...INCREASING SOUTHWEST FLOW OVERNIGHT WITH INCREASING SKY COVER. MOST AREAS WILL BE VFR WITH CLOUD BASES LOWERING TO 4000-5000 FEET. SOUTHWEST WIND OFF THE OCEAN MAY BRING SCATTERED SNOW SHOWERS TO PARTS OF THE SOUTH COAST OF RI AND MASS INCLUDING THE CAPE AND ISLANDS. CIGS WOULD LOWER TO MVFR IN/NEAR ANY SNOW SHOWERS WITH VSBYS OF 3 MILES. PROBABILITY OF SNOW IS TOO LOW FOR IT TO APPEAR IN THE TAFS AT THIS TIME. THURSDAY...VFR. CLEARING SKIES. WEST-SOUTHWEST WINDS GUSTING 20-30 KNOTS EXCEPT 30-35 KNOTS CAPE AND ISLANDS. THURSDAY NIGHT...CLEARING SKIES. WEST WINDS DIMINISHING INLAND BUT GUSTING 20-30 KNOTS ALONG THE COAST AND ISLANDS. KBOS TERMINAL...HIGH CONFIDENCE. KBDL TERMINAL...HIGH CONFIDENCE. OUTLOOK...FRIDAY THROUGH SUNDAY... FRIDAY AND SATURDAY...HIGH CONFIDENCE. MAINLY VFR. NW GUSTS POSSIBLE 20 TO 25 KTS ON FRI. LIGHTER WINDS SAT. SUNDAY...MODERATE CONFIDENCE. MAINLY VFR. SW WIND GUSTS INCREASE TO AROUND 25 KTS AGAIN.
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&& .MARINE...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH THURSDAY. TONIGHT...SOUTHWEST WINDS ALOFT WILL INCREASE DURING THE NIGHT. THE COMBINATION OF COLD AIR ALOFT AND RELATIVELY WARM OCEAN TEMPS...10-14C...WILL ENCOURAGE SOME OF THIS WIND DOWN TO THE OCEAN SURFACE. THE SOUTHWEST LOW LEVEL JET HAS SPEEDS OF 35 TO 40 KNOTS...SO THAT MEANS A GOOD POTENTIAL FOR GALE FORCE SOUTHWESTERS LATER TONIGHT. A GALE WARNING HAS BEEN ISSUED FOR THE OUTER WATERS/SOUTHERN SOUNDS/CAPE COD BAY WITH SMALL CRAFT ADVISORIES FOR NARRAGANSETT BAY/BOSTON HARBOR/MASS BAY. MASS BAY WINDS ARE BORDERLINE AND MAY NEED TO BE UPGRADED OVERNIGHT. THURSDAY...CONTINUED WEST TO SOUTHWEST WINDS AS A COLD FRONT APPROACHES THE WATERS. CONTINUED SPEEDS OF 35 KNOTS MOST WATERS WHERE GALES WARNINGS WILL CONTINUE. CONTINUED 25-30 KNOTS CLOSER TO SHORE WHERE SMALL CRAFT ADVISORY WILL CONTINUE. THURSDAY NIGHT...WINDS AND SEAS WILL DIMINISH DURING THE NIGHT. BUT WEST-SOUTHWEST GALES MAY LINGER ON THE OUTER WATERS FOR A FEW HOURS EARLY IN THE NIGHT BEFORE GOING SUB-GALE. OUTLOOK...FRIDAY THROUGH SUNDAY... FRI...HIGH CONFIDENCE. WINDS AND SEAS REMAIN ABOVE SMALL CRAFT ADVISORY THRESHOLDS...WITH GUSTS APPROACHING 30 KT AND SHIFTING TO THE NW ON FRI. SEAS START AROUND 6-10 FT...BUT THEN GRADUALLY DIMINISH THROUGH THE PERIOD. SAT...HIGH CONFIDENCE. WINDS SHIFT TO THE W-SE BUT REMAIN BELOW SCA CRITERIA AND SEAS ALSO BELOW SCA THRESHOLDS. SUN...MODERATE CONFIDENCE. WINDS SHIFT TO THE S-SW...WITH GUSTS UP TO SMALL CRAFT ADVISORY THRESHOLDS AT LEAST...BUT MAY HAVE A FEW GALE FORCE GUSTS. SEAS INCREASE TO 5-7 FT ON THE OCEAN WATERS.
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&& .CLIMATE... RECORD LOW MAX TEMPS TODAY... BOSTON 30/1897 PROVIDENCE33/1936 HARTFORD33/1955 WORCESTER29/2008 BLUE HILL27/1897 && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ231>235-237-250-251-254>256.
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&& $$ SYNOPSIS...WTB/DOODY NEAR TERM...WTB SHORT TERM...WTB LONG TERM...DOODY AVIATION...WTB/DOODY MARINE...WTB/DOODY CLIMATE...

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