Area Forecast Discussion
Issued by NWS Boston, MA

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194 FXUS61 KBOX 120005 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 705 PM EST THU FEB 11 2016 .SYNOPSIS... MUCH COLDER AIRMASS MOVES INTO THE REGION TONIGHT OM GUSTY NORTHWEST WINDS. AN OCEAN STORM WILL TRACK WELL OFFSHORE FRIDAY NIGHT BUT WILL BRING A PERIOD OF ACCUMULATING SNOW TO THE CAPE AND ISLANDS. AN ARCTIC FRONT WILL DELIVER BITTERLY COLD WEATHER THIS WEEKEND WITH DANGEROUSLY COLD WIND CHILLS. TEMPERATURES MODERATE MONDAY. FOR TUESDAY AND TUESDAY NIGHT...A STORM WILL LIKELY BRING SNOW QUICKLY CHANGING TO RAIN ALONG THE COAST AND TO FREEZING RAIN AND THEN RAIN INLAND AS MUCH MILDER AIR MOVES INTO NEW ENGLAND. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... ***WIND CHILLS DROPPING TO BETWEEN 0 AND 10 BELOW ZERO LATE TONIGHT INTO EARLY FRIDAY MORNING*** 7 PM UPDATE... RADAR DEPICTS AN EXTENDED LAKE ENHANCED BAND FROM LAKE ONTARIO TO THE BERKSHIRES BUT IT STRUGGLES TO STAY TOGETHER OVER THE BERKSHIRE CREST. A FEW BANDS OF OCEAN EFFECT SNOW SHOWERS DEPICTED OFFSHORE AND SHOULD REMAIN OFFSHORE. OTHERWISE...A FEW FLURRIES SPILLING OVER THE BERKSHIRE CREST AND ACROSS SW HARTFORD COUNTY SHOULD DISSIPATE LATER THIS EVENING. CURRENT TEMPERATURES WERE RUNNING 2 OR 3 DEGREES BELOW THE FORECAST AT 7 PM...BUT THE FORECAST MINIMUM TEMPERATURES STILL LOOK REASONABLE. JUST TWEAKED THE HOURS TEMPERATURES AND DEWPOINTS A LITTLE. PRIOR DISCUSSION... SCT FLURRIES AND SNOW SHOWERS MOVING ACROSS SNE THIS AFTERNOON WILL DISSIPATE BY EVENING FOLLOWED BY CLEARING SKIES TONIGHT AS GOOD MID LEVEL DRYING MOVES IN. STRONG COLD ADVECTION ON GUSTY NW WINDS WITH 850 MB TEMPS DROPPING TO -20C TONIGHT...THEN WINDS GRADUALLY DIMINISH OVERNIGHT. MIN TEMPS WILL BE MOSTLY IN THE SINGLE NUMBERS...EXCEPT TEENS CAPE/ISLANDS. WIND CHILLS WILL DROP TO ZERO TO 10 BELOW OVERNIGHT. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... FRIDAY... HIGH PRES MOVES OFF MID ATLC COAST WITH SUNSHINE GIVING WAY TO INCREASING AFTERNOON CLOUDS AS NEXT POTENT SHORTWAVE MOVES INTO THE GT LAKES. WITH DEEPER MOISTURE REMAINING SOUTH AND WEST OF THE REGION IT SHOULD REMAIN DRY THROUGH THE DAY. THERE IS A LOW PROB OF A FEW OCEAN EFFECT FLURRIES/SNOW SHOWERS OVER CAPE/ISLANDS TOWARD EVENING WITH SW FLOW AND COLD AIR ALOFT YIELDING OCEAN INDUCED CAPES AROUND 500 J/KG...BUT MOISTURE IS VERY SHALLOW WHICH WILL LIMIT ACTIVITY. MAX TEMPS WILL BE MOSTLY IN THE LOW AND MID 20S...WITH UPPER TEENS HIGHER TERRAIN. WINDS WILL BE LIGHT. FRIDAY NIGHT... *** ACCUMULATING SNOW LIKELY ACROSS CAPE/ISLANDS *** INTERESTING SET UP AS OCEAN STORM TRACKS WELL OFFSHORE BUT POTENT MID LEVEL TROF/SHORTWAVE APPROACHING FROM THE WEST WILL INDUCE AN INVERTED TROF WHICH EXTENDS ACROSS SE NEW ENG. MODELS ARE IN FAIRLY GOOD AGREEMENT ON DEEPENING MOISTURE AND AREA OF GOOD LOW LEVEL CONVERGENCE AND MODEST OMEGA IN THE SNOW GROWTH REGION...FOCUSED ACROSS CAPE/ISLANDS FRI NIGHT WHICH SHOULD BRING A PERIOD OF SNOW. SOME OCEAN ENHANCEMENT LIKELY GIVEN STEEP LOW LEVEL LAPSE RATES AND OCEAN INDUCED CAPES AROUND 500 J/KG YIELDING POTENTIAL FOR BRIEF HEAVIER SNOW. SNOW ACCUM OF 1-3 INCHES EXPECTED WITH LOW RISK OF UP TO 4 INCHES. ADVISORIES MAY BE NEEDED. SNOW SHOWERS WILL LIKELY EXTEND ACROSS S COASTAL MA WITH MINOR ACCUM POSSIBLE BUT MAIN FOCUS EXPECTED TO BE ACROSS CAPE/ISLANDS. OTHERWISE...ARCTIC FRONT WILL BE APPROACHING FROM THE WEST LATE FRI NIGHT AND WILL LIKELY BRING A FEW SNOW SHOWERS TO WESTERN NEW ENG. && .LONG TERM /SATURDAY THROUGH THURSDAY/... HIGHLIGHTS... * SNOW SHOWERS ENDING OVER THE CAPE AND ISLANDS SAT * BITTER COLD ARCTIC AIR MOVES INTO SOUTHERN NEW ENGLAND FOR THE WEEKEND * SNOW CHANGING TO RAIN LIKELY TUE AND TUE NIGHT OVERVIEW... CLOSED UPPER LOW PASSES ACROSS NEW ENGLAND SAT NIGHT ABOVE COLDEST ARCTIC AIR WITNESSED HERE IN QUITE A WHILE. STRONG SURFACE PRESSURE GRADIENT WILL MOST LIKELY RESULT IN GALES ACROSS THE OCEAN WATERS AND WIND CHILLS APPROACHING OR EXCEEDING WIND CHILL WARNING CRITERIA OVER MUCH OF THE FORECAST AREA. UPPER LOW AND SURFACE HIGH MOVE EAST SUN AND MON. SHORT WAVE TROF AMPLIFIES LONG WAVE TROF POSITION IN NORTH AMERICA BUT SO SHARPLY THAT SURFACE LOW LOOKS TO MOVE NORTH ALONG OR JUST EAST OF THE APPALACHIANS AS AN INSIDE RUNNER. WITH THE SURFACE HIGH BEING SHOWN TO MOVE OFF THE COAST IT IS NOT THE RIGHT SYNOPTIC SET UP FOR COLD AIR DAMMING. THUS...ANY SNOW OR FREEZING RAIN AT THE OUTSET WILL LIKELY CHANGE RATHER QUICKLY TO RAIN EVEN FAR INLAND. THE ONLY CAVEAT IS THAT THIS EVENT IS STILL SEVERAL DAYS AWAY AND COULD SEE SOME VARIATIONS IN MODEL OUTPUT AS THE ENERGY REACHING NORTH AMERICA BECOMES BETTER RESOLVED IN THE UPPER AIR NETWORK. DETAILS... SAT...SNOW ON THE OUTSKIRTS OF AN OCEAN STORM SHOULD END ACROSS CAPE COD...MARTHA/S VINEYARD AND NANTUCKET DURING SAT MORNING. OCEAN EFFECT SNOW SHOWERS MAY PERSIST FOR A WHILE LONGER OVER THE OUTER CAPE. ALTHOUGH THERE WILL BE AN IMPRESSIVE LOW LEVEL LAYER OF A VERY STEEP LAPSE RATE...THE MEAN FLOW IN THE LOWER LEVELS HAS ENOUGH WESTERLY COMPONENT TO KEEP MOST OF THE SNOW SHOWERS OFFSHORE. THE MAIN SHOW OF THE ARCTIC BLAST ARRIVES BY SAT AFTERNOON WITH STRONG NW WINDS DRIVING WIND CHILLS DRAMATICALLY LOWER DURING THE AFTERNOON AND HENCE BEGINNING THE WIND CHILL WATCH AT 1800 UTC OR 1 PM EST. THE TEMPERATURES THEMSELVES MAY RISE A FEW DEGREES OR SO FROM EARLY MORNING TO MIDDAY AND THEN FALL STEADILY THROUGHOUT THE AFTERNOON. SAT NIGHT...MAIN STORY WILL BE THE BITTER COLD. WIND CHILL WATCH IN EFFECT FOR POTENTIAL WIND CHILLS OF -25 TO -30 ACROSS MOST OF THE FORECAST AREA. THE WIND CHILL WATCH COVERS ALL BUT THE CAPE AND ISLANDS. LATER SHIFTS MAY NEED TO REEVALUATE TO SEE IF THE WATCH NEEDS TO BE EXPANDED TO THE CAPE...MARTHA/S VINEYARD...NANTUCKET AND BLOCK ISLAND. NEAR RECORD LOW TEMPERATURES ARE FORECAST FOR SUN MORNING AT MOST SOUTHERN NEW ENGLAND LOCATIONS INCLUDING BOSTON...WORCESTER AND HARTFORD/WINDSOR LOCKS. MODEL CONSENSUS BRINGS 850 MB TEMPERATURES WITHIN A DEGREE OR TWO OF -30C SAT NIGHT. OCEAN EFFECT SNOW SHOWERS WILL LIKELY REMAIN JUST OFFSHORE. SUN...AIR MASS SLOWLY BEGINS TO MODERATE TO -20C TO -22C AT 850 MB BUT STILL VERY COLD. ANTICIPATE MOST HIGH TO BE IN THE SINGLE DIGITS TO LOWER TEENS ACROSS SOUTHERN NEW ENGLAND. THERE SHOULD BE PLENTY OF SUNSHINE BUT STILL A BRISK NW WIND INTO THE EARLY AFTERNOON. THE WIND CHILL WATCH EXPIRES AT 1 PM. SUN NIGHT...CLEAR SKIES AND LIGHTER WINDS OVER THE SNOW COVER SHOULD BE A GOOD SET UP FOR EFFICIENT RADIATIONAL COOLING. TEMPERATURES WILL LIKELY DROP TO NEAR OR SEVERAL DEGREES BELOW ZERO MOST INTERIOR LOCATIONS AND NOT TOO MUCH ABOVE ZERO ACROSS THE SE URBAN CENTERS. MON...TEMPERATURES MODERATE CONSIDERABLY ALTHOUGH MAX TEMPERATURES WILL LIKELY TOP OFF BELOW FREEZING OUTSIDE OF THE CAPE AND ISLANDS. HIGH CLOUDS AHEAD OF A VIGOROUS SHORT WAVE DROPPING INTO THE MEAN LONG WAVE POSITION WILL INCREASE DURING THE AFTERNOON. MON NIGHT THROUGH TUE NIGHT...MODEL CONSENSUS IS FOR A SHARPENING TROF OVER THE EAST CENTRAL CONUS WITH ASSOCIATED SURFACE LOW THAT RUNS NEAR OR JUST EAST OF THE APPALACHIANS. THERE IS CURRENTLY GOOD MODEL CONSENSUS FOR AN INSIDE RUNNER...ALTHOUGH THE EVENT IS STILL SEVERAL DAYS AWAY. CURRENT MODEL CONSENSUS WOULD FAVOR SNOW CHANGING RATHER QUICKLY TO FREEZING RAIN AND THEN RAIN INLAND AND TO JUST RAIN ALONG THE COAST. A STRONG LOW LEVEL JET AT 925 MB IN EXCESS OF 80 KT MAY PRESENT A WIND ISSUE IF ENOUGH OF THAT MOMENTUM CAN MIX TO THE SURFACE...A QUESTION MARK AS AN INVERSION IS LIKELY TO EXIST. SIGNIFICANT ENOUGH RAFL FOR LOCAL STREET FLOODING IS POSSIBLE...BUT CONFIDENCE ON QPF THIS FAR OUT IS QUITE LOW. WED THROUGH THU...FOR NOW THIS PERIOD LOOKS TO BE DRY WITH SHORT WAVE ENERGY NOT SHARP ENOUGH TO PRODUCE A SIGNIFICANT SURFACE REFLECTION. HOWEVER...SOME PRIOR MODEL RUNS HAVE SHOWN A CLIPPER DURING THIS TIME PERIOD AND SO CONFIDENCE IS NOT ALL THAT HIGH. IF NOTHING ELSE...THE SHORT WAVE TROF SHOULD HELP USHER IN ANOTHER SHOT OF ARCTIC AIR BUT NOT NEARLY TO THE EXTENT OF WHAT IS EXPECTED THIS WEEKEND. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY NIGHT/... THROUGH 00Z...SCT SNOW SHOWERS AND MVFR CONDITIONS CONFINED TO E MA THIS AFTERNOON...OTHERWISE MAINLY VFR WITH SCT FLURRIES AND BRIEF MVFR. PARTIAL CLEARING TOWARD EVENING. W/NW GUSTS TO 25-30KT. TONIGHT...HIGH CONFIDENCE. AREAS OF VFR CIGS THIS EVENING...CLEARING BY 03Z. W/NW GUSTS TO 20-30 KT IN THE EVENING...DIMINISHING OVERNIGHT INLAND BUT REMAINING GUSTY ALONG THE COAST THROUGH THE NIGHT. FRIDAY...HIGH CONFIDENCE. MAINLY VFR...BUT SOME MVFR CIGS MAY DEVELOP IN THE AFTERNOON NORTH OF THE MASS PIKE. FRIDAY NIGHT...MODERATE CONFIDENCE. CONDITIONS LOWERING TO MVFR/IFR CAPE/ISLANDS AS SNOW OVERSPREADS THE REGION WITH SOME ACCUM LIKELY. SCT SNOW SHOWERS MAY EXTEND INTO SE MA...OTHERWISE A MIX OF VFR/MVFR CIGS. KBOS TERMINAL...HIGH CONFIDENCE. VFR THROUGH THE PERIOD. KBDL TERMINAL...HIGH CONFIDENCE. VFR THROUGH THE PERIOD. OUTLOOK /SATURDAY THROUGH TUESDAY/... SAT THROUGH SUN...MODERATE TO HIGH CONFIDENCE. MVFR CIGS/VSBYS IN SNOW SHOWERS OVER THE CAPE AND ISLAND...IMPROVING DURING SAT AFTERNOON. OTHERWISE...VFR FOR THE PERIOD BUT GUSTY NW SURFACE WINDS. MON...HIGH CONFIDENCE. VFR. MON NIGHT THROUGH TUE...LOW TO MODERATE CONFIDENCE. BECOMING IFR WITH SNOW CHANGING TO RAIN WITH AREAS OF FOG LATE MON NIGHT INTO TUE. STRONG SOUTHERLY WINDS ALOFT MAY RESULT IN SIGNIFICANT LOW LEVEL WIND SHEAR TUE AFTERNOON. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE. TONIGHT AND FRI...A PERIOD OF W/NW GALES AROUND 35 KT THROUGH THIS EVENING IN STRONG COLD ADVECTION. WINDS SLOWLY DIMINISH OVERNIGHT AND DROP BELOW SCA FRI MORNING WITH LIGHT SW WINDS DEVELOPING FRI AFTERNOON. AREAS OF MODERATE FREEZING SPRAY OVER E MA WATERS AND CAPE COD BAY TONIGHT SO FREEZING SPRAY ADVISORY WILL CONTINUE. FRI NIGHT...WINDS AND SEAS BELOW SCA. SW WINDS BECOMING NW AFTER MIDNIGHT...INCREASING TOWARD DAYBREAK. VSBYS REDUCED IN AREAS OF SNOW. OUTLOOK /SATURDAY THROUGH TUESDAY/... MODERATE TO HIGH CONFIDENCE. STRONG SURFACE PRESSURE GRADIENT AND COLD AIR ADVECTION IS EXPECTED TO RESULT IN GALE FORCE NW WINDS ACROSS ALL WATERS SAT AFTERNOON INTO SUN. IN ADDITION...THERE IS A RISK FOR HEAVY FREEZING SPRAY SAT NIGHT INTO SUN MORNING. WINDS AND SEAS SUBSIDE SUN NIGHT AND MON. A DEVELOPING LOW MOVING ALONG OR JUST EAST OF THE APPALACHIANS MAY PRODUCE SOUTHERLY WINDS OF GALE FORCE ACROSS AT LEAST SOME OF THE WATERS TUE ALONG WITH BUILDING SEAS. && .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... CT...WIND CHILL WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR CTZ002>004. MA...WIND CHILL WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR MAZ002>021-026. RI...WIND CHILL WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR RIZ001>007. MARINE...GALE WARNING UNTIL 4 AM EST FRIDAY FOR ANZ231>235-237-250-251- 254>256. SMALL CRAFT ADVISORY UNTIL 4 AM EST FRIDAY FOR ANZ230-236. FREEZING SPRAY ADVISORY UNTIL 7 AM EST FRIDAY FOR ANZ231-250- 251. && $$ SYNOPSIS...KJC/THOMPSON NEAR TERM...KJC/THOMPSON SHORT TERM...KJC LONG TERM...THOMPSON AVIATION...KJC/THOMPSON MARINE...KJC/THOMPSON CLIMATE...

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