Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 280600 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 100 AM EST SAT FEB 28 2015 .SYNOPSIS... HIGH PRESSURE SLOWLY BUILDING IN FROM THE WEST WILL BRING DRY BUT UNSEASONABLY COLD WEATHER INTO SUNDAY MORNING. A LOW PRESSURE SYSTEM WILL BRING A PLOWABLE SNOW LATE SUNDAY AND SUNDAY NIGHT. ANOTHER STORM IS LIKELY TUESDAY NIGHT INTO WEDNESDAY...WITH SNOW AND MIXED PRECIPITATION LIKELY CHANGING TO RAIN. COLD AND DRY CONDITIONS RETURN FOR THE END OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 1 AM UPDATE... CLEAR SKIES...LIGHT WINDS AND DEEP SNOW PACK WAS ALLOWING FOR AN IDEAL NIGHT OF RADIATIONAL COOLING. A FEW OF THE NORMALLY COLDEST OUTLYING LOCATIONS WERE ALREADY BELOW ZERO...WHILE SOME OF THE MORE URBANIZED AREAS WERE STILL IN THE MIDDLE TO UPPER TEENS AS OF 1 AM. LOW TEMPS SHOULD BOTTOM OUT BETWEEN 5 AND 15 BELOW ZERO ACROSS THE NORMAL COLDEST OUTLYING LOCATIONS! MEANWHILE...OTHER AREAS THAT TYPICALLY DO NOT RADIATE AS WELL WILL SEE LOW TEMPS IN THE SINGLE DIGITS TO THE LOWER TEENS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... SATURDAY AND SATURDAY NIGHT...HIGH PRESSURE REMAINS IN CONTROL OF THE REGION. DESPITE A FRIGID START TO THE DAY...TEMPERATURES WILL REBOUND INTO THE MID TO UPPER 20S SATURDAY AFTERNOON. LIGHT WINDS AND THE HIGHER SUN ANGLE WILL AID IN IT FEELING A BIT MORE TOLERABLE DESPITE TEMPS REMAINING WELL BELOW NORMAL. ANOTHER COLD NIGHT IS EXPECTED SATURDAY NIGHT WITH EXCELLENT RADIATIONAL COOLING. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... HIGHLIGHTS... * PLOWABLE SNOW LIKELY LATE SUN/SUN NIGHT...CLEARING MONDAY * ANOTHER STORM POSSIBLE TUE NIGHT INTO WED...WITH SNOW OR MIXED PRECIP LIKELY CHANGING TO RAIN * COLD AND DRY TOWARD THE END OF THE WEEK SUNDAY... HIGH PRES MOVES OFF THE COAST DURING THE AFTERNOON WITH DEVELOPING WARM ADVECTION PATTERN RESULTING IN SUNSHINE QUICKLY GIVING WAY TO INCREASING CLOUDS. SOME UNCERTAINTY ON TIMING OF LEADING EDGE OF SNOW AND HOW QUICKLY THE COLUMN MOISTENS. SOME LIGHT SNOW MAY DEVELOP BY LATE AFTERNOON. MAX TEMPS UPPER 20S TO LOWER 30S. SUNDAY NIGHT... MODELS SIMILAR WITH LOW PRES TRACKING ACROSS CENTRAL NEW ENG LATE SUN NIGHT...WITH SOME HINT OF A WEAK LOW LEVEL CIRCULATION DEVELOPING SOUTH OF THE COAST. GOOD OVERRUNNING SIGNATURE WITH A PERIOD OF MID LEVEL FGEN AND DECENT PWATS WILL BRING A SLUG OF PRECIP INTO SNE SUN NIGHT. THERMAL PROFILES COLD ENOUGH FOR ALL SNOW...EXCEPT PERHAPS FOR THE ISLANDS WHERE BOUNDARY LAYER WARMING MAY EVENTUALLY FORCE A CHANGE TO RAIN. MODELS IN GOOD AGREEMENT ON QPF WITH 0.25"-0.50"+ FROM NORTH TO SOUTH...HEAVIEST ALONG THE SOUTH COAST. CROSS SECTIONS DO SHOW A PERIOD OF DECENT SNOW GROWTH WITH MAX OMEGA NUDGING INTO -10C LAYER. GENERALLY EXPECTING A GOOD ADVISORY EVENT WITH 3 TO 6 INCHES WITH MAX SNOW ALIGNED ALONG AND SOUTH OF THE MASS PIKE BUT INLAND FROM THE S COAST WHERE SLR MAY BE LOWER DUE TO BL WARMING. A FEW LOCALLY HIGHER AMOUNTS CANT BE RULED OUT ACROSS N CT...N RI AND ADJACENT SE MA. THE SYSTEM IS PROGRESSIVE AND BULK OF SNOW SHOULD BE MOVING OUT BEFORE THE MONDAY MORNING COMMUTE. MONDAY... SOME LINGERING LIGHT SNOW POSSIBLE IN THE MORNING...OTHERWISE MAINLY DRY AS DEEPENING LOW PRES MOVES INTO THE GULF OF MAINE WITH GOOD MID LEVEL DRYING MOVING INTO THE REGION. EXPECT CLEARING SKIES IN THE AFTERNOON BUT BECOMING BLUSTERY WITH NW WINDS GUSTING TO 35 MPH. MAX TEMPS IN THE 30S. MONDAY NIGHT INTO TUE... HIGH PRES BUILDS IN FROM THE WEST. GUSTY WINDS MON EVENING WILL GRADUALLY DIMINISH LATER MON NIGHT INTO TUE AS THE RIDGE CRESTS OVER NEW ENG. TEMPS BELOW NORMAL. TUESDAY NIGHT INTO WEDNESDAY NIGHT... MODELS IN AGREEMENT ON DEEPENING LOW PRES MOVING UP THROUGH THE LAKES WITH NOT MUCH HINT OF SECONDARY LOW DEVELOPMENT. WITH LOW LEVEL S/SW FLOW IT WILL BE VERY DIFFICULT TO LOCK IN THE COLD AIR SO AN EVENTUAL CHANGE TO RAIN IS EXPECTED...QUICKEST ALONG THE COAST TUE NIGHT...BUT ECMWF IS QUITE A BIT COLDER THAN GFS ON THE FRONT END OF THE STORM TUE NIGHT AND WOULD SUGGEST A DECENT ACCUM OF SNOW/ICE IN THE INTERIOR BEFORE GOING TO RAIN WED. GFS WOULD SUGGEST A FAIRLY RAPID TRANSITION FROM SNOW TO RAIN TUE NIGHT. DUE TO UNCERTAINTY WE BLENDED THE GFS/ECMWF PARTIAL THICKNESSES AND HAVE PRECIP STARTING AS SNOW EVERYWHERE TUE NIGHT THEN TRANSITIONING TO A MIX/ICE OVERNIGHT IN THE INTERIOR WITH RAIN ALONG THE COAST...THEN ALL RAIN WED. SNOWPACK WILL BE ABLE TO ABSORB THE RAINFALL AND OTHER THAN AREAS OF POOR DRAINAGE FLOODING DUE TO CLOGGED DRAINS...FLOODING IS NOT ANTICIPATED. THE OTHER ITEM OF UNCERTAINTY IS HOW QUICKLY THE RAIN EXITS. GFS IS MOST PROGRESSIVE AND DRIES IT OUT WED NIGHT...WHILE ECMWF HAS MORE AMPLIFIED UPSTREAM TROF WHICH SLOWS THE FRONT DOWN WITH POTENTIAL FRONTAL WAVE BRINGING ANOTHER PERIOD OF RAIN WED NIGHT INTO EARLY THU. CONSENSUS OF THE GUIDANCE FAVORS ECMWF SOLUTION. STILL LOTS OF UNCERTAINTY THIS FAR OUT AND HOW THIS PLAYS OUT WILL AFFECT FORECAST POPS/TEMPS/PTYPE. A SOLUTION CLOSER TO ECMWF WOULD RESULT IN MILDER TEMPS WED NIGHT WITH MORE RAIN. THURSDAY AND FRIDAY... PRECIP COULD LINGER INTO THU MORNING IF ECMWF SOLUTION IS CORRECT...BUT TREND THROUGH THE END OF THE WEEK WILL BE FOR COLDER AND DRY CONDITIONS WITH TEMPS DROPPING WELL BELOW NORMAL...ESPECIALLY THU NIGHT AND FRI. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TODAY THROUGH SUNDAY NIGHT/... TODAY AND TONIGHT...HIGH CONFIDENCE IN VFR CONDITIONS. SUNDAY AND SUNDAY NIGHT...MODERATE CONFIDENCE. VFR CONDITIONS EXPECTED SUN MORNING WITH AN INCREASE IN MID LEVEL CLOUDINESS. SNOW OVERSPREADS THE REGION FROM WEST TO EAST LATE SUN AFTERNOON AND EARLY EVENING. CIGS/VSBYS WILL DETERIORATE TO MVFR OR IFR LEVELS BY EARLY EVENING. THE HEAVIEST SNOW FALLS SUN NIGHT...RESULTING IN WIDESPREAD IFR TO LIFR CONDITIONS. SNOW MAY MIX WITH OR CHANGE TO RAIN FOR A TIME ACROSS PORTIONS OF SOUTHERN RI AND FAR SOUTHEAST MA...ESPECIALLY IMMEDIATE SOUTH COAST/CAPE AND ISLANDS. PRECIP SHOULD RAPIDLY END FROM WEST TO EAST TOWARD DAYBREAK MONDAY....WITH IMPROVING CONDITIONS. KBOS TAF...HIGH CONFIDENCE IN VFR CONDITIONS INTO SUNDAY MORNING. KBDL TAF...HIGH CONFIDENCE IN VFR CONDITIONS INTO SUNDAY MORNING. OUTLOOK...MONDAY THROUGH WEDNESDAY... MONDAY...MODERATE CONFIDENCE. MVFR/IFR POSSIBLE EARLY...THEN IMPROVING TO VFR. NW WIND GUSTS TO 30 KT DEVELOPING IN THE AFTERNOON. TUESDAY...HIGH CONFIDENCE. MAINLY VFR. TUESDAY NIGHT INTO WEDNESDAY...CONDITIONS LOWERING TO IFR WITH SNOW CHANGING TO ICE THEN RAIN...QUICKEST ALONG THE COAST. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE. HIGH PRESSURE BUILDS OVER THE WATERS FROM THE WEST ALLOWING WINDS AND SEAS TO SUBSIDE GRADUALLY. SEAS REMAIN ABOVE 5 FEET ON THE OUTER WATERS SO AM ALLOWING THE SMALL CRAFT ADVISORY TO CONTINUE ON THOSE WATERS THROUGH TONIGHT. OUTLOOK...SUNDAY THROUGH WEDNESDAY...HIGH CONFIDENCE. SUNDAY...LIGHT WINDS AND SEAS SUN...THEN SW INCREASING TO 10-20 KT SUN NIGHT. VSBYS REDUCED IN RAIN/SNOW SUN NIGHT. MONDAY...INCREASING NW WINDS DEVELOP WITH GALE FORCE GUSTS POSSIBLE IN THE AFTERNOON AND EVENING BEFORE DIMINISHING OVERNIGHT. TUESDAY...WINDS BELOW SCA WITH SUBSIDING SEAS AS HIGH PRES CRESTS OVER THE WATERS. LATE TUE NIGHT INTO WEDNESDAY...INCREASING SW WINDS WITH GUSTS TO SCA THRESHOLDS. LOWERING VSBYS IN SNOW CHANGING TO RAIN. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR ANZ250-254>256. && $$ SYNOPSIS...KJC/RLG NEAR TERM...FRANK SHORT TERM...RLG LONG TERM...KJC AVIATION...FRANK/KJC MARINE...KJC/RLG

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.