Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 130918 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 418 AM EST SAT FEB 13 2016 .SYNOPSIS...
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AN ARCTIC FRONT WILL DELIVER DANGEROUSLY COLD WIND CHILLS OF 20 TO 35 BELOW ZERO LATER TODAY INTO SUNDAY MORNING. A PERIOD OF ACCUMULATING SNOW AND ICE IS THEN LIKELY FOR MUCH OF REGION ESPECIALLY AWAY FROM THE COAST MONDAY AFTERNOON AND EVENING. A POWERFUL STORM SYSTEM WILL LIKELY TRACK WEST OF NEW ENGLAND TUE/TUE NIGHT BRINGING HEAVY RAIN...STRONG WINDS AND WARM TEMPERATURES TO THE REGION. A TREND TOWARD DRIER AND COLDER WEATHER FOLLOWS NEXT WED AND THU.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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*** ARCTIC COLD FRONT WILL BRING STRONG WIND GUSTS AND A RAPID FALL IN TEMPERATURES THIS AFTERNOON/EARLY EVENING *** DISTANT OCEAN STORM WILL CONTINUE TO MOVE FURTHER WAY FROM THE REGION EARLY THIS MORNING. THIS WILL ALLOW THE STEADY SNOW TO COME TO AN END ACROSS THE CAPE/ISLANDS BETWEEN 10 AND 12Z. WILL ALLOW WINTER WEATHER ADVISORY TO EXPIRE AT 7 AM FOR NANTUCKET. OTHERWISE...THE MAIN STORY WILL BE THE ARCTIC COLD FRONT THAT WILL SWEEP ACROSS THE REGION THIS MORNING. NOT MUCH LOW LEVEL MOISTURE AVAILABLE...SO OTHER THAN A BRIEF PASSING FLURRY/SNOW SHOWER IT WILL COME THROUGH DRY. HOWEVER...A BRUTAL SURGE OF ARCTIC AIR ACCOMPANIED BY STRONG WIND GUSTS WILL RESULT IN A RAPID FALL IN TEMPS THROUGH THE AFTERNOON. 850 TEMPERATURES CRASH TO BETWEEN -26 TO -30C BY 00Z...WHICH IS VERY RARE FOR SOUTHERN NEW ENGLAND STANDARDS. MORNING HIGH TEMPS MAINLY IN THE TEENS TO LOWER 20S WILL PLUMMET THROUGH THE AFTERNOON/EARLY EVENING. BY EARLY EVENING...TEMPERATURES WILL ALREADY BE BELOW ZERO ACROSS THE INTERIOR AND SINGLE DIGITS ALONG THE COASTAL PLAIN. WIND GUSTS WILL LIKELY OVER ACHIEVE TODAY BASED ON STRONG PRESSURE RISES BEHIND THE FRONT AND EXCELLENT MIXING WITH SUCH COLD AIR MOVING IN ALOFT. EXPECT NORTHWEST WIND GUSTS OF 35 TO 45 MPH WITH A FEW GUSTS TO 50 MPH THAT WILL DEVELOP THIS AFTERNOON. WIND ADVISORIES WERE NOT ISSUED SINCE THE STRONG WIND GUSTS ARE COVERED BY THE WIND CHILL HEADLINES. BY EARLY EVENING...WIND CHILLS WILL ALREADY HAVE FALLEN TO BETWEEN 10 AND 25 BELOW ZERO!
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
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*** DANGEROUSLY COLD WIND CHILLS OF 20 TO 35 BELOW ZERO TONIGHT INTO SUNDAY MORNING *** *** COLDEST LOW TEMPERATURES SINCE JANUARY 2004 APPEAR LIKELY IN BOSTON AND WORCESTER BY EARLY SUNDAY MORNING *** TONIGHT... BRUTAL SURGE OF ARCTIC AIR WILL CONTINUE TO WORK INTO THE REGION TONIGHT. 850 TEMPERATURES ARE EXPECTED TO BE AROUND -30C BY 6Z WHICH IS EXTREMELY RARE FOR THIS PART OF THE COUNTRY. NORTHWEST WIND GUSTS OF 35 TO 45 MPH WITH A FEW GUSTS NEAR 50 MPH WILL CONTINUE TONIGHT. STRONGEST OF THOSE WINDS WILL OCCUR DURING THE FIRST PART OF THE NIGHT. THE RESULT OF THE STRONG WINDS AND EXTREME COLD WILL RESULT IN WIND CHILL VALUES DROPPING TO BETWEEN 20 AND 35 BELOW ZERO TONIGHT INTO SUNDAY MORNING. 850 TEMPERATURES NEAR -30C WILL SUPPORT LOW TEMPERATURES BELOW ZERO FOR ALL LOCATIONS EXCEPT PORTIONS OF THE OUTER-CAPE COD AND NANTUCKET. MUCH OF THE INTERIOR SHOULD SEE LOW TEMPS BETWEEN 10 AND 15 BELOW ZERO. IT IS APPEARING MORE LIKELY THAT BOTH BOSTON AND WORCESTER WILL RECORD THEIR LOWEST TEMPERATURE IN MORE THAN A DECADE. WE ARE GOING WITH A LOW OF 6 BELOW ZERO IN BOSTON AND 12 BELOW IN WORCESTER...BOTH OF WHICH WOULD BE THE COLDEST SINCE JANUARY OF 2004! WILL DISCUSS THE CONCERN FOR ANOTHER ROUND OF ACCUMULATING SNOW FOR THE OUTER-CAPE TONIGHT/SUNDAY MORNING IN OUR MESOSCALE SECTION. MESOSCALE SETUP FOR THE OUTER-CAPE TONIGHT/SUNDAY MORNING... A RATHER INTERESTING SETUP TONIGHT INTO SUNDAY MORNING FOR THE OUTER- CAPE. A MID LEVEL TROUGH AND ARCTIC SHORTWAVE SLIDE SOUTH IN SOUTHERN NEW ENGLAND. THIS WILL ALLOW FOR DEEPENING LOW LEVEL MOISTURE ACROSS EASTERN NEW ENGLAND. AT THE SAME TIME...VERY EXTREME INSTABILITY WILL DEVELOP OVER THE OCEAN. DELTA T VALUES FROM THE OCEAN TO THE TOP OF THE MIXED LAYER ARE NEAR 35C RESULTING IN OCEAN INDUCED CAPES NEAR 1500 J/KG. THE BIG LIMITING FACTOR WILL BE THE WIND DIRECTION OF 300 TO 310 DEGREES...WHICH NORMALLY IS TOO SHORT A FETCH FOR OCEAN EFFECT. HOWEVER...THIS IS A RARE CASE AND WE SHOULD BE ABLE TO COMPENSATE FOR IT WITH THE EXTREME INSTABILITY. IN ADDITION...SEEDER FEEDER PROCESSES WITH DEEPENING MID LEVEL MOISTURE AND SYNOPTIC FORCING FROM MID LEVEL SHORTWAVE. WILL GO FOR 1 TO 3 INCHES OF SNOW TONIGHT INTO SUNDAY MORNING FOR THE OUTER-CAPE WITH A LOW RISK FOR 4 INCHES. WE WILL RE-ISSUE THE SPECIAL WEATHER STATEMENT TO WRAP UP THE EARLY MORNING SNOW ACROSS CAPE COD AND HIGHLIGHT CONCERNS FOR TONIGHT/SUNDAY MORNING. THERE ALSO IS LOW RISK FOR EVEN A FEW SNOW SHOWERS/FLURRIES ACROSS EASTERN MA WITH MID LEVEL SHORTWAVE. SOME MINOR ACCUMS CAN NOT BE RULED OUT ACROSS CAPE ANN/UPPER CAPE AND NANTUCKET...BUT MAIN FOCUS WILL BE ACROSS THE OUTER-CAPE. SUNDAY... DANGEROUSLY COLD WIND CHILLS OF 20 TO 35 BELOW ZERO WILL BE THE MAIN STORY THROUGH MID MORNING ON SUNDAY. WHILE IT WILL REMAIN BREEZY LATER SUNDAY MORNING AND INTO THE AFTERNOON...WINDS WILL DIMINISH SOME ALLOWING WIND CHILLS TO IMPROVE. NONETHELESS...THEY WILL REMAIN BELOW ZERO ALL DAY. HIGH TEMPERATURES ON SUNDAY WILL ONLY RECOVER INTO THE SINGLE DIGITS AND LOWER TEENS DESPITE PLENTY OF SUNSHINE. OCEAN EFFECT SNOW SHOWERS SUNDAY MORNING ACROSS THE OUTER- CAPE WILL DIMINISH TO FLURRIES SUNDAY AFTERNOON...BUT CLOUDS MAY PERSIST.
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&& .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
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*** DANGEROUSLY COLD WIND CHILLS SUNDAY MORNING *** HIGHLIGHTS... * SOME ACCUMULATING SNOW AND ICE LIKELY MON AFTERNOON/EVENING * TEMPS IN THE 50S TUE-TUE NGT W/HEAVY RAIN AND STRONG WINDS OVERVIEW AND MODEL PREFERENCES... A CHANGEABLE PATTERN THROUGH THE WEEK IS EXPECTED AS THE INITIAL ARCTIC OUTBREAK FROM THE WEEKEND DISSIPATES AND GIVES WAY TO THE SRN STREAM BRIEFLY. HOWEVER...THIS IS NOT LONG LIVED AS A PERSISTENT VORTEX NEAR BAFFIN ISLAND WILL LEAD TO ANOTHER /ALTHOUGH NOT NEARLY AS ROBUST/ ARCTIC INFLUENCE AS STRONG RIDING AMPLIFIES OVER THE WRN HALF OF THE CONUS. THIS RIDGING WILL KEEP THE ARCTIC INFLUENCE SHORT LIVED AS IT ONCE AGAIN ALLOWS FOR SRN STREAM DOMINANCE BY THE END OF THE WEEK. SO...IN OTHER WORDS...A BIT OF A ROLLER COASTER WITH TEMPERATURES DURING THE WEEK. THERE IS REASONABLE AGREEMENT BETWEEN OPERATIONAL MODELS THROUGH THE PERIOD...SUCH THAT A BLEND OF THESE SOURCES SHOULD SUFFICE AS BASELINE FOR MOST OF THE PERIOD. HOWEVER...WILL CONTINUE WITH AN ENSEMBLE BLEND FOR THE LOW PRES PASSAGE LATE MON INTO TUE...THIS IS DUE TO ITS MORE PERSISTENT SUGGESTION OF A WESTERLY TRACK WHEN COMPARED WITH PARTICULARLY THE GFS OPERATIONAL SOLUTION. DETAILS... SUN NIGHT INTO MON... GOOD SETUP FOR RADIATIONAL COOLING SUN NIGHT...SO THANKFULLY NOT AS MUCH WIND TO YIELD THE BITTER WIND CHILLS OF SAT NIGHT. HOWEVER...WITH A SNOWPACK AND COLD H92 TEMPS...INVERSIONS WILL STILL ALLOW SEVERAL LOCATIONS ACROSS THE INTERIOR TO DROP BELOW 0F... WITH ONLY SINGLE DIGITS NEAR THE COAST MON MORNING. THE COLD START...AND CRESTING HIGH PRES WILL MEAN TEMPS ARE NOT GOING TO REBOUND AS WELL AS THEY COULD GIVEN THE H92 TEMPS APPROACH -8C BY AFTERNOON. INCREASING CLOUDS MON WITH HIGHS IN THE 20S AND LOW 30S. MON EVENING INTO TUE NIGHT... SRN STREAM LOW PRES IS CURRENTLY PROGGED TO PASS W OF NEW ENGLAND DURING THE DAY ON TUE. GIVEN THIS HAS SRN STREAM INFLUENCE AND GULF OF MEXICO MOISTURE...PRECIP PRODUCTION WILL BE RELATIVELY EFFICIENT WITH PWATS 2 STD DEVIATIONS ABOVE NORMAL AND A 40-50 KT LLJ. THE INITIAL ISENTROPIC LIFT IS LIKELY TO BE SNOW THANKS TO A LEFTOVER DOME OF COLD AIR IN ADVANCE OF THE WARM ADVECTION. QPF PRIOR TO THE CHANGEOVER SUPPORTS ANYWHERE FROM 1-4 IN OF SNOWFALL..BUT AS MENTIONED BE THE PREVIOUS FORECASTER...THIS IS ONLY AN INITIAL LOOK UNTIL TRACK/THERMAL PROFILES ARE BETTER RESOLVED. THE SNOWFALL COULD ACTUALLY INCREASE THE RISK FOR SOME FZRA/ICE DEVELOPMENT INITIALLY AS THE CHANGEOVER TO RAIN OCCURS AND SFC TEMPS REMAIN NEAR FREEZING. HOWEVER...EXPECT ALL RAIN BY ABOUT SUNRISE ON TUE DUE TO INFLUENCE OF THE LLJ. PERIODS OF HEAVY RAIN POSSIBLE AT TIMES TUE...WITH FINAL LIQUID TOTALS OF AN INCH OR MORE POSSIBLE. MODERATING TEMPS SUGGEST LOWS NEAR NORMAL BUT HIGHS ABOVE NORMAL AND IN THE 40S TO EVEN NEAR 50 BY TUE AFTERNOON. WED AND WED NIGHT... ARCTIC SHORTWAVE WILL ROTATE THROUGH THE MUCH SUPPRESSED LONGWAVE TROF ASSOCIATED WITH BAFFIN LOW CUTOFF. AT THIS POINT...IT/S LIKELY THIS WILL PASS WITH LITTLE FANFARE EXCEPT MAYBE A FEW -SHSN THANKS TO COLD ADVECTIVE DRIVEN INSTABILITY. WILL NEED TO WATCH SOME OFFSHORE WAVE DEVELOPMENT...BUT THIS APPEARS TO BE TOO PROGRESSIVE FOR A NORMAL HIT...HENCE THE LOWER END POPS. HIGHS IN THE 30S AND 40S DUE TO THE LATE PASSAGE WED EVENING...OVERNIGHT LOWS IN THE TEENS AND 20S. THU AND FRI... HIGH PRES ASSOCIATED WITH COLD AIRMASS EXPECTED THU. H85 TEMPS ONLY DROP TO AROUND -18C AS COMPARED TO THE -30C EXPECTED THIS WEEKEND. BUT THIS IS STILL ENOUGH TO KEEP HIGHS THU IN THE 20S AND LOW 30S AND OVERNIGHT MINS IN THE LOW TEENS WITH A FEW SINGLE DIGITS. SOME WARMING EXPECTED FRI AS THE HIGH SHIFTS E AND ALLOWS MODEST RETURN FLOW. EXPECT HIGHS BACK IN THE 30S TO AROUND 40 BUT MAINLY DRY WX TO PREVAIL. NEXT WEEKEND... ALTHOUGH THERE IS SOME UNCERTAINTY FOLLOWING THE RIDGING...W-E TRAVERSING WAVE WILL APPROACH AND CURRENTLY LOOKS TO BE YET ANOTHER INSIDE RUNNER BASED ON THE SHARPENING TROF. STILL LOT/S OF TIME HERE...BUT CONDITIONS LOOK TO BE MORE ACTIVE FOLLOWING THE LATE WEEK HIGH PRES.
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&& .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TODAY THROUGH SUNDAY/... TODAY...MODERATE TO HIGH CONFIDENCE. SNOW AND ASSOCIATED IFR CONDITIONS ACROSS CAPE/ISLANDS SHOULD COME TO AN END BY 11 OR 12Z. OTHERWISE...MAINLY VFR CONDITIONS IN MOST LOCALES TODAY...BUT SOME MVFR CIGS POSSIBLE AT TIMES ESPECIALLY CAPE/ISLANDS. GENERALLY DRY TODAY OTHER THAN A BRIEF PASSING FLURRY/SNOW SHOWER. BIG STORY WILL BE ARCTIC FRONT WHICH WILL ALLOW NORTHWEST WIND GUSTS OF 35 TO 40 KNOTS TO DEVELOP BY AFTERNOON. TONIGHT...HIGH CONFIDENCE. NORTHWEST WIND GUSTS OF 30 TO 40 KNOTS...STRONGEST OF WHICH WILL OCCUR DURING THE FIRST PART OF THE NIGHT. MAINLY VFR EXCEPT CAPE/NANTUCKET WHERE MVFR CONDITIONS ARE EXPECTED IN OCEAN EFFECT CLOUDS/SCATTERED SNOW SHOWERS. BULK OF THE SCATTERED SNOW SHOWERS WILL BE FOUND ACROSS THE OUTER-CAPE. LOW RISK THAT A PERIOD OF MVFR CIGS WORK INTO EASTERN MA FOR A TIME LATE TONIGHT. SUNDAY...HIGH CONFIDENCE. MAINLY VFR WITH NORTHWEST WIND GUSTS OF 20 TO 25 KNOTS. THE EXCEPTION WILL BE PORTIONS OF CAPE/NANTUCKET WHERE MVFR CIGS MAY PERSIST INTO THE AFTERNOON. OCEAN EFFECT SNOW SHOWERS MAINLY ACROSS OUTER-CAPE SHOULD WIND DOWN SUNDAY AFTERNOON. KBOS TERMINAL...MODERATE TO HIGH CONFIDENCE IN TAF. KBDL TERMINAL...MODERATE TO HIGH CONFIDENCE IN TAF. OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/... SUN NIGHT INTO MON...HIGH CONFIDENCE. HIGH PRES YIELDS A PERIOD OF MAINLY VFR CONDITIONS. MON EVENING INTO TUE NIGHT...MODERATE CONFIDENCE. MIX OF IFR/MVFR...FIRST AS SNOWFALL OVERSPREADS THE REGION MON NIGHT...CHANGING TO A MIX OF RAIN AND POSSIBLE BRIEF PERIOD OF FREEZING RAIN. ALL RAIN EXPECTED ON TUE. WINDS WILL BE SHIFTING BUT GUSTS TO 20-30 KT POSSIBLE MAINLY DURING THE DAY TUE. LLWS POSSIBLE TUE AS WELL. WED...MODERATE CONFIDENCE. MAINLY VFR...BUT BRIEF SHRA/SHSN POSSIBLE.
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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. SHORT TERM /THROUGH SUNDAY/...HIGH CONFIDENCE. *** GALE FORCE WIND GUSTS AND HEAVY FREEZING SPRAY EXPECTED THIS AFTERNOON INTO SUNDAY MORNING *** TODAY THROUGH SUNDAY...HIGH CONFIDENCE. MAIN STORY IS THE INCREDIBLY STRONG ARCTIC COLD FRONT THAT WILL CROSS THE REGION THIS MORNING. 850 TEMPERATURES DROPPING TO BETWEEN -25 AND -30C OVER THE RELATIVELY MILD OCEAN WILL RESULT IN NORTHWEST GALE FORCE WIND GUSTS THIS AFTERNOON INTO SUNDAY MORNING. EXTREMELY COLD AIR/STRONG WINDS WILL RESULT IN AREAS OF HEAVY FREEZING SPRAY AND ARCTIC SEA SMOKE. GALE/FREEZING SPRAY HEADLINES ARE IN EFFECT INTO SUNDAY MORNING. FINALLY...OCEAN EFFECT SNOW SHOWERS WILL RESULT IN POOR VISIBILITY AT TIMES. OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/... SUN NIGHT INTO MON...HIGH CONFIDENCE. WINDS AND SEAS WILL DISSIPATE AS HIGH PRES MOVES OVER THE REGION. A PERIOD OF MAINLY QUIET BOATING WEATHER IS EXPECTED AFTER THE WINDS SUBSIDE AND FREEZING SPRAY SUBSIDES. TUE NIGHT INTO WED...MODERATE CONFIDENCE. A PERIOD OF AT LEAST SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED AS LOW PRES MOVES INLAND. GUSTS COULD REACH GALE FORCE DURING THE DAY ON TUE...BUT STRONG SMALL CRAFTS ARE EXPECTED AT LEAST. WAVES REACH 8-10FT BUT THEN DISSIPATE.
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&& .CLIMATE... BITTERLY COLD TEMPERATURES ARE EXPECTED THIS WEEKEND. RECORD COLD HIGH AND LOW TEMPERATURES MAY BE TIED OR BROKEN. HERE ARE THE CURRENT RECORDS FOR THE WEEKEND. RECORD COLD HIGHS FOR FEB 13TH - 14TH... BOSTON.......15/1979 - 14/1916 HARTFORD.....11/1979 - 11/1979 PROVIDENCE...10/1979 - 10/1979 WORCESTER.... 8/1899 - 7/1979 BLUE HILL.... 9/1899 - 10/1979 RECORD COLD LOWS FOR FEB 13TH - 14TH - 15TH... BOSTON...... -3/1967 - -3/1934 - -14/1943 HARTFORD.... -7/1967 - -9/1979 - -18/1943 PROVIDENCE.. -5/1967 - -7/1979 - -14/1943 WORCESTER...-12/1967 - -11/1979 - -19/1943 BLUE HILL...-10/1967 - -9/1979 - -18/1943 && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...WIND CHILL WARNING FROM 4 PM THIS AFTERNOON TO NOON EST SUNDAY FOR CTZ002>004. MA...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST SUNDAY FOR MAZ022>024. WIND CHILL WARNING FROM 4 PM THIS AFTERNOON TO NOON EST SUNDAY FOR MAZ002>019-026. WIND CHILL WARNING FROM 1 PM THIS AFTERNOON TO NOON EST SUNDAY FOR MAZ020-021. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR MAZ024. RI...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST SUNDAY FOR RIZ008. WIND CHILL WARNING FROM 4 PM THIS AFTERNOON TO NOON EST SUNDAY FOR RIZ001>004. WIND CHILL WARNING FROM 1 PM THIS AFTERNOON TO NOON EST SUNDAY FOR RIZ005>007. MARINE...HEAVY FREEZING SPRAY WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST SUNDAY FOR ANZ231>235-237-250-251-254>256. GALE WARNING FROM 11 AM THIS MORNING TO 10 AM EST SUNDAY FOR ANZ231>235-237-250-251-254>256. GALE WARNING FROM 11 AM THIS MORNING TO 7 AM EST SUNDAY FOR ANZ230-236.
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&& $$ SYNOPSIS...FRANK/DOODY NEAR TERM...FRANK SHORT TERM...FRANK LONG TERM...DOODY AVIATION...FRANK/DOODY MARINE...FRANK/DOODY CLIMATE...STAFF

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