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000 FXUS61 KBOX 090008 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 708 PM EST WED FEB 8 2012 .SYNOPSIS... LOW PRESSURE PASSING WELL OFFSHORE TONIGHT MAY CLIP THE SOUTH COAST...CAPE COD AND THE ISLANDS WITH A BRIEF PERIOD OF LIGHT SNOW SHOWERS OR FLURRIES. DRY WEATHER WITH ABOVE NORMAL TEMPERATURES WILL RETURN FOR THURSDAY AND FRIDAY. LOW PRESSURE MAY DEVELOP SOUTH OF NEW ENGLAND SATURDAY...WHICH MAY BRING A PERIOD OF LIGHT SNOW OR A MIX OF RAIN AND SNOW TO THE REGION. AN ARCTIC FRONT WILL MOVE THROUGH LATE THIS WEEKEND...USHERING IN A BRIEF SHOT OF ARCTIC AIR LATE SUNDAY INTO MONDAY. TEMPERATURES WILL THEN MODERATE TUE AND WED OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 707 PM UPDATE... NOT MUCH CHANGE FROM PREVIOUS FORECAST WITH THE THEME REMAINING THE SAME...LIGHT SNOW OR FLURRIES FOCUSED ALONG THE SOUTH COAST OF MA AND RI. PRECIP SHIELD CONTINUES TO ERODE AS IT OVERSPREADS SOUTHERN NEW ENGLAND IN RESPONSE TO LOW LEVEL DRY AIR /DEW PTS IN THE SINGLE DIGITS AND TEENS/ OVER THE REGION. THUS GREATEST CHANCE OF SNOW WILL BE ALONG THE SOUTH COAST WHERE SURFACE DEW PTS ARE HIGHER AND CLOSER TO APPROACHING JET DYNAMICS. STARTING TO SEE SOME ENHANCEMENT ON SATELLITE AND RADAR OVER EASTERN PA AND NJ AS MID LEVEL SHORT WAVE APPROACHES THIS REGION. THIS AREA OF SNOW WILL MOVE ENE AND OVERSPREAD COASTAL SECTIONS OF CT/RI AND SOUTHEAST MA BETWEEN 03Z-09Z FROM WEST TO EAST. 15Z SREF POPS REFLECT THIS WELL WITH FLURRIES POSSIBLE FROM BDL-ORH-BOS. AS PREVIOUS FORECAST INDICATED NOT MUCH IF ANY ACCUMULATION EXPECTED. PREVIOUS DISCUSSION BELOW. UPPER LEVEL SHORTWAVE IS STILL ON TRACK AND IS CURRENTLY EJECTING OUT OF THE OHIO VALLEY AT THIS TIME. THIS SHORTWAVE HAS SPAWNED SNOW SHOWERS ACROSS EASTERN PENNSYLVANIA AND ACROSS NEW JERSEY OVER THE PAST HOURS. HOWEVER BECAUSE OF THE LARGE TEMP/DEWPOINT SPREAD ACROSS THE AREA...BELIEVE IT WILL BE SOME TIME IN THE EVENING FOR A CHANCE OF SNOW TO OCCUR. TEMPERATURES ARE STILL ON TRACK FOR THE REMAINDER FOR THE DAY WHILE DEWS CONTINUE TO BE A TAD TRICKY AS WE HAVE MIXED OUT TODAY. HAVE ADJUSTED THE FORECAST TO ACCOUNT FOR THIS TREND. BELIEVE THAT WITH THE APPROACHING SYSTEM...AND THE SOUTHERLY SHIFT IN THE WINDS...MOISTURE WILL BEGIN TO INCREASE ACROSS THE AREA. TONIGHT... UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION DURING THE OVERNIGHT HOURS...THIS WILL BRING THE REGION A CHANCE FOR RAIN/SNOW SHOWERS ESP ALONG THE SOUTH COAST. GENERALLY GOOD MODEL AGREEMENT ACROSS THE BOARDS. JUST UNCERTAIN ON EXACTLY WHEN THE GRADIENT OF SNOW VS NO SNOW WILL SET UP. THE GFS/ECMWF ARE STILL IN GOOD AGREEMENT WITH THE GRADIENT LINE BEING A TAD NORTHWARD HITTING PVD AND MOST OF THE CAPE WHILE THE NAM/SREF ARE STILL FOCUSING MORE ACROSS THE ISLANDS AND EXTREME SOUTHERN COAST LINE. WITH THIS IN MIND...BELIEVE THE AREAS THAT WILL SEE THE BEST SNOWFALL WILL BE MARTHAS VINEYARD...NANTUCKET...AND THE SOUTH SHORE OF THE CAPE/RI. EXPECT SNOW AMOUNTS TO RANGE FROM A TRACE UP TO A HALF OF AN INCH...AS QPF WILL BE QUIET LIMITED WITH THIS SYSTEM. EXPECT SNOW TO BEGIN BY THE EVENING HOURS AND LAST THROUGH THE EARLY MORNING...WHICH MAY CAUSE SOME ISSUES WITH THE MORNING COMMUTE ACROSS THE SOUTH SHORE...CAPE AND ISLANDS. LOW TEMPS TONIGHT WILL BE WARMER THAN THE PREV NIGHT...AS CLOUDS WILL HELP KEEP TEMPS FROM RADIATING OUT. EXPECT TEMPS TO DROP DOWN INTO THE UPPER TEENS ACROSS THE INTERIOR TO THE MID TO UPPER 20S ALONG THE COAST AND URBAN CITIES. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... THURSDAY... THIS WEEKS TEMPERATURE ROLLER COASTER WILL CONTINUE AS MAX TEMPS ON THURSDAY WILL WARM UP TO THE MID TO UPPER 40S ACROSS MOST OF THE AREA AS LOW 40S WILL OCCUR ACROSS WESTERN MASS AND INTO NH. THIS WARM UP IS THANKS TO SLIGHT RIDGING MOVING ACROSS SOUTHERN NEW ENGLAND...SHIFTING THE WINDS TO THE SOUTHWEST. BELIEVE THIS WILL BE A LATE DAY RALLY AS THERE WILL STILL BE A GOOD AMOUNT OF CLOUDS INTO THE LATE MORNING FROM THE SHORTWAVE THAT PASSED THROUGH DURING THE OVERNIGHT TIMEFRAME. THURSDAY NIGHT... THE QUIET WEATHER TREND WILL CONTINUE AS HIGH PRESSURE CONTINUES TO BUILD THROUGH THE AREA. WITH CLEAR SKIES AND LIGHT WINDS...TEMPS WILL DROP TO THE UPPER TEENS IN THE INTERIOR TO THE MID TO UPPER 20S ACROSS THE COASTAL REGIONS THANKS TO THE WARM START FROM THE DAY. OTHERWISE...TEMPS WOULD BE QUIET CHILLY. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... HIGHLIGHTS... * DRY AND ABOVE NORMAL TEMPS FRI * ARCTIC COLD STILL EXPECTED SUN AND MON * LOW PROBABILITY OF SNOW SHOWERS AND MINOR ACCUMULATIONS SAT/SAT NIGHT 12Z GFS AND 12Z ECMWF CONTINUE TO DIVERGE ON THE WEEKEND FORECAST. BOTH MODELS AGREE ON THE POLAR VORTEX DROPPING SOUTHWARD INTO ME AND THE MARITIMES...HOWEVER MODELS DIFFER ON THE AMPLITUDE OF SHORT WAVE ENERGY EJECTING FROM THE VORTEX INTO NEW ENGLAND. THE ECMWF AND ITS PREVIOUS RUNS CONTINUE TO PUT MORE EMPHASIS ON THE LEAD SHORT WAVE SATURDAY WHICH INDUCES CYCLOGENESIS WELL SOUTHEAST OF NEW ENGLAND. HOWEVER THERE IS SUFFICIENT MID LEVEL LIFT AND MOISTURE /PER THE EC/ WITH THE ACCOMPANYING FRONT TO YIELD WIDESPREAD SNOW SHOWERS /POSSIBLY MIXED WITH RAIN SOUTH COAST/ SAT WITH A LOW PROBABILITY OF MINOR ACCUMULATIONS. THIS SOLUTION ALSO SUPPORTS A PERIOD OF OCEAN EFFECT SNOWS FOR CAPE COD SAT NIGHT. HOWEVER THE 12Z GFS AND ITS PREVIOUS RUNS ARE PLACING MORE STOCK IN A TRAILING SHORT WAVE SUN WITH THE ATTENDING ARCTIC FRONT. THIS SOLUTION SUPPORTS A POSSIBLE WINDEX EVENT WITH SNOW SQUALLS ALONG AND AHEAD OF THE ARCTIC FRONT SUNDAY AS IT CROSSES SOUTHERN NEW ENGLAND. SO QUITE THE MODEL SPREAD! THE NAM SUPPORTS THE GFS BUT THE 50 MEMBER ECENS AND THE GFS MOS POPS SUPPORT THE 12Z ECMWF. THUS WE FOLLOWED THE GFS MOS POPS FOR SAT FOLLOWED BY MAINLY DRY WEATHER SUN. HOWEVER CAN`T RULE OUT A SNOW SHOWER WITH THE PASSAGE OF THE ARCTIC FRONT SUN. TEMPS MAY FALL SHORT OF RECORD COLD SUN AND MON HOWEVER GUSTY WNW WINDS WILL COMBINE WITH ACTUAL AIR TEMPS IN THE SINGLE DIGITS SUN NGT TO YIELD BITTERLY COLD WIND CHILLS BELOW ZERO. ALL MODEL GUIDANCE IN GOOD AGREEMENT THAT UPPER AIR PATTERN REMAINS PROGRESSIVE WITH POLAR VORTEX EJECTING QUICKLY OUT OF THE MARITIMES AS THE PATTERN DEAMPLIFIES. THIS SHOULD YIELD HIGHS CLIMBING BACK INTO THE 40S TUE-WED NEXT WEEK. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MODERATE...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT AFTER 00Z... 707 UPDATE... HIGH CONFIDENCE IN VFR CONDITIONS AT MOST TERMINALS. HOWEVER...THERE IS A LOW TO MODERATE PROBABILITY OF BRIEF MVFR CONDITIONS IN LIGHT RAIN/SNOW SNOW SHOWERS ACROSS COASTAL SECTIONS OF CT/RI AND SOUTHEAST MA. LITTLE IF ANY SNOW ACCUMULATION EXPECTED. THURSDAY...LOW PROBABILITY OF LEFT OVER EARLY MORNING MVFR CONDITIONS ACROSS THE CAPE/NANTUCKET IN LIGHT SNOW SHOWERS/FLURRIES. OTHERWISE...HIGH CONFIDENCE IN VFR CONDITIONS. KBOS TERMINAL...HIGH CONFIDENCE IN VFR CONDITIONS TODAY AND TONIGHT DESPITE MID LEVEL CLOUDINESS. THURSDAY NIGHT...HIGH CONFIDENCE IN VFR CONDITIONS DUE TO HIGH PRESSURE. OUTLOOK...FRIDAY THROUGH MONDAY... FRIDAY...HIGH CONFIDENCE FOR VFR CONDITIONS AND DRY WEATHER. SATURDAY AND SUNDAY...LOW CONFIDENCE FORECAST ON TIMING OF ARCTIC FRONT THIS WEEKEND. LIGHT SNOWFALL MAY PRECEDE THE FRONT SAT INTO SAT NIGHT...WITH LOCAL MVFR CIGS/VSBYS ESPECIALLY SOUTHEAST MA. N-NW WIND GUSTS UP TO 25-30 KT LATE SAT...THEN AGAIN DURING SUN. MON...MODERATE TO HIGH PROBABILITY OF VFR ALONG WITH DRY WEATHER. && .MARINE... TONIGHT... A WEAK PRESSURE GRADIENT WILL RESULT IN WINDS AND SEAS WELL BELOW SCA THRESHOLDS. A PERIOD OF LIGHT RAIN/SNOW SHOWERS MAY AFFECT THE SOUTHERN WATERS FOR A TIME TONIGHT...ESPECIALLY TO THE SOUTH OF THE ISLANDS. THURSDAY-THURSDAY NIGHT... LOW PRESSURE PASSING WELL SOUTH OF THE WATERS EARLY THU SHOULD RESULT IN NORTHWEST WINDS OF 10 TO 15 KNOTS DEVELOPING. GUSTS AROUND 20 KNOTS ARE EXPECTED...BUT WIND GUSTS AND SEAS SHOULD REMAIN BELOW SCA THRESHOLDS. WESTERLY WINDS WILL SWITCH TO THE SOUTHWEST OVERNIGHT WITH WINDS AND GUST SUBSIDING AFTER SUNSET. OUTLOOK...FRIDAY THROUGH MONDAY... FRIDAY...SW WINDS AHEAD OF APPROACHING FRONT. DRY WEATHER SHOULD PREVAIL. SATURDAY...LOW CONFIDENCE FORECAST. LOW PRES MAY DEVELOP SOUTH OF NEW ENGLAND BUT LIKELY NOT EVOLVE INTO A GALE CENTER UNTIL SAT NIGHT AS IT TRACKS OVER EASTERN GEORGES BANK. THIS MAY YIELD A PERIOD OF LOW END GALE FORCE WINDS SAT NIGHT OVER THE EASTERN MA WATERS ALONG WITH SCATTERED SNOW SHOWERS. SUNDAY...ARCTIC FRONT LIKELY TO CROSS SOUTHERN NEW ENGLAND WITH NW GALES ON THE BACK SIDE ALONG WITH A HIGH PROBABILITY OF MODERATE FREEZING SPRAY AND A LOW PROBABILITY OF HEAVY FREEZING SPRAY. SNOW SHOWERS WELL OFFSHORE GIVEN THE NW WIND TRAJECTORY. MON...IMPROVING CONDITIONS WITH WINDS EASING AND MODERATING TEMPERATURES. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...NOCERA/DUNTEN NEAR TERM...NOCERA/DUNTEN - UPDATED 707 PM SHORT TERM...DUNTEN LONG TERM...NOCERA AVIATION...NOCERA/DUNTEN - UPDATED 707 PM MARINE...NOCERA/DUNTEN
