Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 250840 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 440 AM EDT WED MAR 25 2015 .SYNOPSIS... HIGH PRESSURE MOVES OFFSHORE TODAY ALLOWING MORE SEASONABLE AIR TO RETURN TO NEW ENGLAND. A WARM FRONT MOVES ACROSS NEW ENGLAND TONIGHT BRINGING A PERIOD OF RAIN...FOLLOWED BY CLOUDS/DRIZZLE/FOG. ANOTHER AREA OF RAIN MOVES THROUGH ON THURSDAY. A COLD FRONT SWEEPS ACROSS THE REGION THURSDAY NIGHT WITH SHOWERS. A SECOND COLD FRONT WILL BRING COLDER TEMPERATURES LATER FRIDAY INTO THIS WEEKEND. ANOTHER FAST MOVING FRONT WILL PUSH ACROSS THE REGION SUNDAY NIGHT INTO MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THROUGH 8 AM... HIGH PRESSURE CENTERED OVER NEW ENGLAND WITH CLEAR SKIES ACROSS THE REGION. PER SATELLITE THE NEAREST CIRRUS WAS LOCATED IN WESTERN NY/WESTERN PA AT 2 AM. THIS WILL MOVE EAST AT A PACE THAT WILL BRING IT INTO SOUTHERN NEW ENGLAND AROUND SUNRISE. FAIR SKIES AND LIGHT WINDS WILL ALLOW COOLING TEMPERATURES THROUGH SUNRISE WITH DEW POINTS IN THE TEENS AND LOWER 20S ALLOWING AN EXPECTED RANGE OF MORNING LOWS IN THE MID TEENS TO MID 20S. TODAY... INCREASING HIGH CLOUDS MORNING AND MIDDAY BUT PLENTY OF SUN THROUGH THAT SKY COVER. SO EXPECT TEMPERATURES TO RECOVER FROM THE CHILLY START. TEMPS ALOFT THROUGH 18Z WOULD SUPPORT MAX SFC TEMPS IN THE 40S. SOUTHERLY LOW LEVEL JET REMAINS TO OUR WEST AT 18Z BUT SHIFTS INTO SOUTHERN NEW ENGLAND BY 00Z. SO EVEN WITH INCREASING CLOUDS THE WEATHER SHOULD REMAIN DRY THROUGH ALMOST ALL OF THE DAY. COULD BE A CHANCE OF INITIAL LIGHT SHOWERS IN WESTERN MASS/CT AROUND 5 PM. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... TONIGHT... PRIME ZONE OF WARM ADVECTION LIFT MOVES THROUGH DURING THE FIRST HALF OF THE NIGHT AND THEN MOVE EAST OF US AFTER MIDNIGHT. THE WARM ADVECTION THEN REACHES THE SURFACE AND SHOULD PROVIDE FOR WARMING TEMPS OVERNIGHT...A DECIDED NON-DIURNAL TREND. WE HAVE ADJUSTED HOURLY TEMPS TO REFLECT THIS. THE WARM ADVECTION...WITH DEW POINTS RISING ABOVE FREEZING TO AROUND 40...SHOULD BRING AREAS OF FOG AS IT RIDES OVER THE SNOWPACK. WITH NEARSHORE WATER TEMPS IN THE 30S...THE HIGHER DEW POINT AIR MOVING ASHORE ALONG THE SOUTH COAST MAY ALSO BE SUFFICIENTLY CHILLED TO CREATE AREAS OF FOG. THURSDAY... COLD FRONT STARTS THE DAY EXTENDING FROM NORTHERN VERMONT TO THE OHIO VALLEY. THIS AXIS HAS A NORMAL COMPONENT TO THE UPPER FLOW BUT IS NOT FAR FROM BEING PARALLEL. THE FRONT WILL BE SUPPORTED BY A 155 KNOT UPPER JET OVER THE GREAT LAKES WITH RIGHT ENTRANCE REGION OVER ILLINOIS/INDIANA. SURPRISE...A WAVE OF LOW PRESSURE DEEPENS IN THIS LOCATION AS IT MOVES UP THE FRONT. THIS WILL BRING A STRONG LOW LEVEL SOUTHWEST JET UP TOWARD NEW ENGLAND WHICH SHOULD GENERATE ANOTHER PERIOD OF RAIN OVER OUR AREA BY AFTERNOON. ACTUALLY IT/S A TOUGH CALL FOR RAIN VS SHOWERS...THE PATTERN LOOKS STRATIFORM BUT TAKES PLACE AHEAD OF AN ADVANCING COLD FRONT. BASED ON THE LOW LEVEL JET AND RESULTING LIFT WE WILL GO STRATIFORM AT THIS TIME...BUT COULD BE MORE LIKE PERIOD OF RAIN RATHER THAN A LONG SOAKING RAIN. STABILITY PARAMETERS LOOK FAVORABLE FOR CONVECTION WITH TOTALS IN THE LOWER 50S AND TQ 17 TO 18. THE COOLING BY THE SNOWPACK MAY MAINTAIN A STABLE LAYER AT THE SURFACE...BUT ELEVATED INSTABILITY MAY BE ENOUGH TO SET OF ISOLATED OR WIDELY SCATTERED THUNDER DURING THE AFTERNOON AND EVENING. THE STRONG WARM ADVECTION WILL CONTINUE TO BRING RELATIVELY HIGH DEW POINT AIR...IN THE 40S...ACROSS THE REGION. THIS WILL AID BOTH FOG FORMATION AND SNOWMELT. PRECIPITABLE WATER VALUES CLIMB TO AROUND 1 INCH TO 1.5 INCHES...WHICH IS ABOUT 2 SD ABOVE NORMAL. THIS SUGGESTS POTENTIAL FOR OCCASIONAL HEAVY DOWNPOURS. 950 MB TEMPS 8-10C BROUGHT TO THE SURFACE ISOTHEMALLY WOULD START TEMPERATURES AT 45-50. ALLOW SOME MINIMAL WARMING DURING THE MORNING AND POTENTIAL IS THERE FOR MAX TEMPS 50-55. THURSDAY NIGHT... THE SURFACE LOW PASSES TO OUR NORTH AND THEN SWINGS THE COLD FRONT THROUGH SOUTHERN NEW ENGLAND DURING THE NIGHT. LOW CONFIDENCE ON EXACT TIMING...BUT THE WIND SHIFT SHOULD COINCIDE WITH DIMINISHING SHOWERS. WE STAYED CLOSE TO BLENDED MODEL GUIDANCE FOR MIN TEMPS LATE THURSDAY NIGHT. && .LONG TERM /FRIDAY THROUGH TUESDAY/... HIGHLIGHTS... * BLUSTERY AND BELOW AVERAGE TEMPS FOR THE WEEKEND * WEAK DISTURBANCE POSSIBLE ON MONDAY MODEL GUIDANCE... OVERALL AMPLIFIED TROUGH PATTERN WILL CONTINUE WITH 00Z GUIDANCE IN GOOD AGREEMENT. STILL SOME TIMING/INTENSITY ISSUES FOR UPCOMING SYSTEMS. DEEP TROUGH AXIS WILL MOVE OVERHEAD SAT INTO EARLY SUNDAY FOLLOWED BY A QUICK MOVING RIDGE. BY LATE SUNDAY INTO MONDAY ANOTHER SHORTWAVE WILL MOVE INTO SOUTHERN NEW ENGLAND. GUIDANCE IS SPLIT ON THIS SYSTEM AS THE GFS IS MORE AMPLIFIED COMPARED TO THE EC. OTHERWISE...MIDDLE OF NEXT WEEK LOOKS TO BE A POSSIBLE PATTERN CHANGE. DETAILS... * FRIDAY INTO SATURDAY...MODERATE CONFIDENCE. DEEP SHORTWAVE WILL DIG FROM THE GREAT LAKES DOWN INTO THE SOUTHEAST ALLOWING FOR DEEP TROUGH TO SETTLE OVER THE NORTHEAST BY LATE FRIDAY/SATURDAY. PRIOR TOO THIS SECONDARY COLD FRONT WILL SWEEP ACROSS THE AREA FROM WEST TO EAST ON FRIDAY PUSHING MOST OF THE PRECIP OFFSHORE...BUT USHERING COLDER AIR ALOFT. THIS FRONTAL PASSAGE WILL OCCUR LATE IN THE DAY/EVENING HOURS TO MUCH OF THE REGION MAY REACH INTO THE MID 40S TO LOW 50S. COULD SEE A FEW POP UP SHOWERS ALONG THE FRONT AS IT PASSES THROUGH AS THERE IS SOME LINGER MOISTURE. AM NOT EXPECTING MUCH IN THE WAY OF ACCUMULATIONS. COLD AIR WILL USHER ACROSS THE REGION FRIDAY NIGHT INTO SATURDAY. AS UPPER LEVEL TROUGH PUSHES OVERHEAD...COULD SEE SOME SCT SNOW SHOWERS DURING THE DAY ON SATURDAY. FEEL THESE MAY BE MORE CONVECTIVELY DRIVEN AS THERE IS SOME MOISTURE IN THE LOW LEVELS AND LAPSE RATES STEEPEN DURING THE DAY. THEREFOR INSERT SLIGHT CHC POP INTO THE FORECAST...WITH THE AREA WITH THE BEST CHANCE OF SEEING A SNOW SHOWER BEING WEST OF I-95. TEMPS OVERNIGHT WILL FALL WELL BELOW NORMALS WITH LOWS AROUND THE TEENS TO LOW 20S. TEMPS MAY BE SLIGHTLY COLDER AT WE COULD RADIATE OUT THANKS TO CLEARING SKIES AND LIGHT WINDS ACROSS THE INTERIOR. * SUNDAY...HIGH CONFIDENCE. SUNDAY IS A TRANSITION DAY AS DEEP TROUGH BEGINS TO PULL OFFSHORE AND UPPER LEVEL RIDGE MOVES INTO THE REGION. TEMPS ON SUNDAY WILL WARM INTO THE LOW TO MID 40S...WHICH IS STILL SEVERAL DEGREES BELOW AVERAGE. EXPECT MOSTLY CLEAR SKIES IN THE MORNING BUT THEY WILL BEGIN TO CLOUD UP DURING THE AFTERNOON AS THE NEXT SYSTEM APPROACHES FROM THE WEST. MONDAY INTO TUESDAY...LOW CONFIDENCE. NEXT UPPER LEVEL DISTURBANCE WILL IMPACT SOUTHERN NEW ENGLAND LATE SUNDAY INTO MONDAY. STILL A GOOD AMOUNT OF SPREAD AMONGST THE GUIDANCE WITH THE EC KEEPING THE SYSTEM TO THE NORTH WHILE THE GFS BRINGS THE SYSTEM OVER SNE. CONTINUED TO KEEP PRECIP IN THE FORECAST FOR NOW WITH THIS SYSTEM. SURFACE LOW ACROSS THE GREAT LAKES WILL PASS JUST NORTH OF SNE...DRAGGING ASSOCIATED COLD FRONT WITH IT. TEMPS AT THE ONSET LOOK TO BE COOL THEN WARM UP DURING THE DAY ON MONDAY PRIOR TO FRONTAL PASSAGE. THIS MAY CAUSE P-TYPE ISSUES...BUT BECAUSE THIS IS SEVERAL DAYS AWAY WILL NEED TO REEVALUATE. FRONT WILL PASS THROUGH LATE MONDAY WITH HIGH PRESSURE AND COOLER TEMPS IN ITS WAKE FOR TUESDAY. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH WEDNESDAY...THEN SOME UNCERTAINTY ON EXACT TIMING OF LOWER CIGS/VSBYS WITH RAIN LATE WED INTO WED EVENING. THROUGH 12Z/8 AM...HIGH CONFIDENCE. VFR CLR. LIGHT/VRBL OR CALM WINDS. TODAY...VFR. CLOUDS LOWER AND THICKEN DURING THE AFTERNOON/EVENING. MVFR CIGS/VSBYS DUE TO RAIN MAY ENTER THE CT RIVER VALLEY BETWEEN 21Z AND 00Z THIS EVENING. TONIGHT...CONDITIONS LOWERING TO MVFR WITH AREAS OF IFR DUE TO LOW CIGS/RAIN/FOG. RAIN TAPERS OFF AFTER MIDNIGHT BUT IFR/LIFR DUE TO LOW CIGS/FOG/DRIZZLE THROUGH SUNRISE. THURSDAY...ANOTHER AREA OF RAIN MOVES IN FROM THE SOUTHWEST. MIXED MVFR/IFR CIGS/VSBYS IN RAIN AND FOG. LOCALLY HEAVY DOWNPOURS POSSIBLE THURSDAY NIGHT AS A COLD FRONT SWINGS THROUGH. LOW CONFIDENCE FOR ISOLATED THUNDERSTORMS LEADING THE FRONT THURSDAY EVENING/NIGHT. BEST CHANCE FOR THUNDER WOULD BE ACROSS RI AND SOUTHEAST MASS. KBOS TAF...HIGH CONFIDENCE THRU 00Z TODAY THEN SOME UNCERTAINTY ON EXACT TIMING OF LOWERING CONDITIONS. KBDL TAF...HIGH CONFIDENCE THRU 21Z TODAY THEN SOME UNCERTAINTY ON EXACT TIMING OF LOWERING CONDITIONS. OUTLOOK...FRIDAY THROUGH SUNDAY...MODERATE TO HIGH CONFIDENCE FRIDAY THROUGH SATURDAY...MVFR CONDITIONS IMPROVING TO VFR FROM WEST TO EAST ON FRIDAY. COULD SEE ISO/SCT MVFR CIGS ALONG COLD FRONT ON FRIDAY AND AGAIN DIURNALLY DRIVEN ON SATURDAY. SATURDAY NIGHT INTO SUNDAY...VFR CONDITIONS LIKELY. && .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 TODAY THEN MODERATE CONFIDENCE TONIGHT AND THURSDAY. TODAY...LIGHT WINDS BECOME SOUTH THIS AFTERNOON. WINDS AND SEAS REMAIN BELOW SMALL CRAFT THRESHOLDS. CHANCE OF LIGHT RAIN TOWARD EVENING. TONIGHT...SOUTH TO SOUTHWEST WINDS WILL INCREASE TO 20-25 KNOTS. THIS WILL BUILD SEAS TO 5 FEET ON THE OUTER WATERS AND 3-4 FEET CLOSER TO SHORE. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR SOME OF THE EASTERN WATERS. THE SOUTH WIND WILL TRANSPORT INCREASING HUMIDITY WITH DEW POINTS AT LEAST IN THE 40S. AS THIS MOVES OVER 38 DEGREE WATER IT MAY GENERATE LOW VSBYS IN FOG ACROSS THE WATERS...ESPECIALLY SOUTH OF NEW ENGLAND. THURSDAY AND THURSDAY NIGHT...INCREASING SOUTHWEST WINDS WITH FREQUENT GUSTS 25-30 KNOTS. THIS WILL BUILD SEAS WITH 5-10 FOOT HEIGHTS EXPECTED ON THE EXPOSED WATERS INCLUDING RI SOUND. HEIGHTS ON THE OUTER WATERS COULD REACH 11 TO 13 FEET AT TIMES. VSBYS WILL REMAIN LOW IN RAIN AND FOG. A COLD FRONT APPROACHES THE WATERS OVERNIGHT THURSDAY NIGHT. OUTLOOK...FRIDAY THROUGH SUNDAY... MODERATE TO HIGH CONFIDENCE FRIDAY. MODERATE CONFIDENCE FRIDAY NIGHT INTO SUNDAY. FRIDAY...WINDS SHIFT TO NW DURING THE DAY AS COLD FRONT PASSES. BUILDING SEAS WILL SLOWLY BEGIN TO SUBSIDE BY FRIDAY NIGHT. GUSTY WINDS LOW END GALES WILL ALSO BEGIN TO DISSIPATE AS THE FRONT PASSES THROUGH. FRIDAY NIGHT INTO SUNDAY...HIGH PRESSURE WILL SLIDE SOUTH OF THE REGION FRIDAY NIGHT/SATURDAY ALLOWING FOR THE WIND AND SEAS TO BEGIN TO SUBSIDE. THIS MAY TAKE SOME TIME AS WE COULD SEE LINGERING SCA WIND GUSTS THANKS TO CAA. SCA MAY BE NEEDED FOR THE WHOLE PERIOD.
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&& .HYDROLOGY... CONTINUE TO NOTE GOOD AMOUNT OF RAINFALL WILL MOVE ACROSS THE REGION...AS WELL AS TEMPERATURES RISING TO THE UPPER 40S TO MID 50S ALONG WITH INCREASING DEWPTS /AT LEAST TO THE 40S/ THURSDAY INTO FRIDAY. THIS WILL COMBINE TO CAUSE SIGNIFICANT SNOW MELT ACROSS THE REGION. EXPECT RAINFALL AMOUNTS TO RANGE FROM 0.5 TO 1 INCH ACROSS THE REGION...POSSIBLY 1.25 IN SPOTS. HIGHEST VALUES WILL BE ACROSS NORTHERN AND WESTERN MASS AND CT. HOWEVER...WITH MILDER TEMPS...WILL SEE A BIG WATER RELEASE WITH THE SNOW TO WATER EQUIVALENT /SWE/ ON ORDER OF 2-5 INCHES. MAY ALSO SEE SOME HEAVIER DOWNPOURS OVERNIGHT THU INTO FRI MORNING ESPECIALLY IF ANY CONVECTION DEVELOPS. COMBINING THE RAPID SNOW MELT WITH THE UPCOMING QPF...MAY SEE 1.5 TO 3 INCHES OF WATER FLOWING INTO AREA RIVERS AND STREAMS. SEVERAL OF THE MAIN STEM RIVER LEVELS MAY APPROACH ACTION STAGE DURING FRIDAY...WITH A COUPLE POSSIBLY APPROACHING MINOR FLOOD STAGE. CURRENT FORECASTS ISSUED BY THE NORTHEAST RIVER FORECAST CENTER HAVE THE DETAILS. CONTINUE TO MONITOR FORECAST UPDATES FOR MORE DETAILS ON THIS EVENT. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO NOON EDT THURSDAY FOR ANZ250-254.
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&& $$ SYNOPSIS...WTB/DUNTEN NEAR TERM...WTB SHORT TERM...WTB LONG TERM...DUNTEN AVIATION...WTB/DUNTEN MARINE...WTB/DUNTEN HYDROLOGY...

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