Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 121405 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1005 AM EDT SAT APR 12 2014 .SYNOPSIS... LOW PRESSURE MOVES OFF THROUGH THE MARITIMES. HIGH PRESSURE BUILDS OVER NEW ENGLAND WITH DRY AND PROGRESSIVELY MILDER CONDITIONS THROUGH MONDAY. A SLOW MOVING FRONT WILL BRING A SOAKING RAIN TUESDAY INTO WEDNESDAY WITH BELOW AVERAGE TEMPERATURES TO FOLLOW. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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10 AM UPDATE... LEFTOVER FOG ALONG THE CT RIVER IN NW MA AND SW NH WILL BE BURNING OFF...OTHERWISE HIGH PRES IN CONTROL THIS AFTERNOON WILL BRING SUNSHINE AND MILD TEMPS. EXPECTED MAX TEMPS WILL REACH AROUND 70 DEGREES IN THE INTERIOR VALLEYS AND INTERIOR E MA/RI. SOUTH COAST SEABREEZE IS EXPECTED TO DEVELOP THIS AFTERNOON WHICH WILL COOL TEMPS BUT EAST COAST SEABREEZE MAY REMAIN JUST OFFSHORE ALLOWING TEMPS TO REACH WELL INTO 60S. PREVIOUS DISCUSSION... HIGH PRESSURE BUILDS OVER NEW ENGLAND AND SHOULD MAINTAIN PLENTY OF SUNSHINE THROUGH THE DAY. THERE SHOULD BE ENOUGH OF A PRESSURE GRADIENT TO MAINTAIN NORTHWEST WINDS IN THE MORNING...BUT THIS DIMINISHES BY AFTERNOON. THE DIMINISHING WIND AND SOLAR HEATING SHOULD ALLOW SEA BREEZES TO DEVELOP...ESPECIALLY ALONG THE SOUTH COAST. MIXING WILL GO DEEP...REACHING AT LEAST TO 850 MB AND POSSIBLY TO 800 MB. TEMPS AT 850 MB AT 4-5C...TEMPS AT 800 MB AROUND 0-2C...THIS WOULD SUPPORT MAX TEMPS 65 TO 70. BEST CHANCE FOR THE LOW 70S WILL BE IF THE MIXING REACHES 800 MB. COOLER TEMPS NEAR THE COASTS.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... TONIGHT... HIGH PRESSURE MOVES OFF TO THE EAST. QUESTION FOR THIS PERIOD TURNS ON A WARM FRONT EXTENDING EAST FROM THE GREAT LAKES...WHERE IN NEW ENGLAND DOES IT GO? UPPER FLOW IS WEST-EAST AND WOULD BRING IT ACROSS VT/NH. FORECAST SURFACE WINDS FOR SATURDAY NIGHT SHOW A 40-50 KNOT SOUTHWEST JET MOVING UP THROUGH THE OHIO VALLEY AND ACROSS NY/VT/NH. SO THE BEST CHANCE OF CLOUDS AND SHOWERS SHOULD BE NORTH OF THE FRONT...AND LIKELY NORTH OF OUR FORECAST AREA. WE SHOULD SEE SOME INCREASE IN MID AND HIGH CLOUDS AS THE WARMER AIR MOVES NORTH ON SOUTHERLY WINDS. COULD ALSO BE PATCHY FOG EARLY MORNING. TEMPS ARE FROM A BLEND OF MODEL DATA...UPPER 30S TO MID 40S. SUNDAY... WARM FRONT REMAINS WELL TO OUR NORTH WITH A SOUTH TO SOUTHWEST FLOW OF AIR. MODEL RH FIELDS SUGGEST AT LEAST SOME CLOUD COVER FROM TIME TO TIME...BUT OVERALL EXPECT A FINE DAY WITH MOSTLY SUNNY SKIES. THE 40-50 KNOT SOUTHWEST JET WILL BE ALOFT AT 2000-5000 FEET...AND SOME OF THIS MAY MIX TO THE SURFACE. TEMPERATURES IN THE MIXED LAYER WILL SUPPORT MAX TEMPS IN THE LOW TO MID 70S...BUT COOLER TEMPS NEAR THE COAST. THE SOUTH FLOW WILL BRING INCREASING DEWPOINTS OVER THE COLD WATERS SOUTH OF NEW ENGLAND. THE REFRIDGERATING WATER WILL CAUSE ENOUGH CONDENSATION FOR FOG AND LOW CLOUDS OFFSHORE. SOME OF THIS MAY MOVE ONSHORE ALONG THE SOUTH COAST LATE SUNDAY AFTERNOON OR EVENING. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... HIGHLIGHTS... * ABOVE AVERAGE TEMPERATURES ARE EXPECTED ON MONDAY * STRONG COLD FRONTAL PASSAGE NEXT TUES/WED * BELOW AVERAGE TEMPERATURES RETURN FOR THE REMAINDER OF THE WORK WEEK MODELS AND CONFIDENCE... HAVE HIGH CONFIDENCE IN THE WARMING TREND IN THE FORECAST OVER THE WEEKEND WITH A MODERATE CONFIDENCE FOR THE TIMING POTENTIAL FOR THE SYSTEM NEXT WEEK. INCREASING CONFIDENCE THAT PRECIP WILL OCCUR DURING THE MID-WEEK BUT THE EXACT TIMING AND LOCATION OF MODERATE RAINFALL ARE STILL UNCERTAIN. IN FACT GUIDANCE IS TRYING TO STALL THE FRONT OUT JUST SOUTH OF THE AREA...HAVE LOW CONFIDENCE THAT THIS WILL OCCUR. FINALLY BELIEVE THAT TEMPS WILL DROP BELOW AVERAGE BY WEDNESDAY. OVERALL 00Z MODEL GUIDANCE IS GENERALLY IN GOOD AGREEMENT. FOR EARLY NEXT WEEK...THE UPPER PATTERN WILL BEGIN TO FAVOR A DIGGING TROUGH ACROSS THE CENTRAL CONUS AS UPPER LEVEL RIDGING BUILDS OVER BOTH COASTLINES. THIS WILL PUSH A WAVY COLD FRONT ACROSS THE CONUS AND INTO SOUTHERN NEW ENGLAND BY TUES/WED. THE UPPER LEVEL FLOW APPEARS TO RAPIDLY FLATTEN...LEAVING THE FRONT OVER THE WRN ATLC FOR THE REST OF THE FCST. THE DETERMINISTIC AND ENSEMBLE GUIDANCE CONTINUE TO SHOW BETTER AGREEMENT ON THE EVOLUTION OF THIS SYSTEM. HOWEVER THE 12Z EC SHOWED A COASTAL LOW DEVELOPING ALONG THE STALLED FRONT AND MOVE WELL INTO SOUTHERN NEW ENGLAND. LOOKING AT OTHER GUIDANCE BELIEVE THIS IS AN OUTLIER...ESP SINCE THE 00Z EC KEEPS THAT POTENTIAL COAST LOW MORE OFFSHORE. IN FACT THERE WAS ONLY 1 MEMBER OF THE GEFS THAT SUPPORTED THE 12Z EC WHILE THE REMAINDER OF THE GEFS/GFS/CMC/UKMET KEEP THE SYSTEM WELL OFFSHORE. THIS WILL ALL BE DETERMINED ON THE STRENGTH OF THE BUILDING HIGH BEHIND THE FRONT. BELIEVE THAT IN THE WAKE OF THE FRONT A STRONG HIGH PRESSURE WILL SETTLE OVER/NEAR NEW ENGLAND. TEMPS SHOULD MODERATE TO WITHIN 10F OF NORMAL BY LATE NEXT WEEK. HAVE TRENDED THIS FORECAST TOWARDS PREVIOUS FORECAST AND A 2:1 RATIO OF EC:GFS. DETAILS... SUNDAY NIGHT INTO MONDAY... WARM FRONT WILL LIFT NORTHWARD ON SUNDAY NIGHT ALLOWING FOR RETURN FLOW TO THE REGION. EXPECT TEMPS TO WARM OVERNIGHT AND WITH THE INCREASING MOISTURE EXPECT PATCHY TO AREAS OF FOG TO DEVELOP. ONLY CAVEAT IS THE GUSTY WINDS...SO BELIEVE BEST AREA WILL BE OVER THE WATERS AND ALONG THE IMMEDIATE SOUTH COAST. AS THE WARM FRONT MOVES THROUGH NEW ENGLAND ON MONDAY...EXCELLENT WAA WILL MOVE INTO THE AREA. SOUNDINGS SHOW THAT THE AREA WILL MIX TO ABOUT 900 MB AND WITH 925 MB TEMPS AROUND 14-16C...HIGH TEMPERATURES WILL FLIRT INTO THE MID TO PERHAPS UPPER 70S ON MONDAY. IF THE ATMOSPHERE IS SUPER ADIABATIC AND CLOUD COVER AHEAD OF THE FRONT BREAKS OUT THEN TEMPERATURES MAY REACH 80F ON MONDAY...ESP NORTH OF THE PIKE. HOWEVER IF YOU ARE ALONG THE SOUTH COASTLINE...SOUTHERLY WINDS WILL BRING THE COOL MARITIME AIR ONSHORE KEEPING TEMPS IN THE LOW 60S. 925 MB LLJ WILL BE INCREASING THROUGHOUT THE DAY AS AN ANOMALOUS COLD FRONT APPROACHES FROM THE WEST. THIS LLJ WILL INCREASE TO ABOUT 40-50KTS AND WITH EXCELLENT MIXING PLACE WE COULD SEE GUSTS BETWEEN 25-35 MPH...AND POSSIBLY FLIRT WITH WIND ADV CRITERIA. MONDAY NIGHT INTO WEDNESDAY.... GUIDANCE IS BEGINNING TO CLUSTER MORE TOGETHER ON THE TIMING AND INTENSITY OF THE APPROACHING COLD FRONTAL SYSTEM. THE LATEST 00Z MODELS INDICATE THAT SEVERAL WAVES WILL DEVELOP ALONG THE SLOW MOVING COLD FRONT ALLOWING FOR MULTIPLE CHANCES FOR HEAVY RAINFALL. ANTICIPATE A FEW SHOWERS TO DEVELOP AHEAD OF THE FRONT MONDAY NIGHT INTO TUESDAY EARLY MORNING. BUT AS SOON AS THE FRONT APPROACHES EXPECT MODERATE TO HEAVY RAINFALL TO FALL. THIS PRECIP MAY CAUSE URBAN AND POOR DRAINAGE FLOODING...AND IT MAY ALSO HELP ELEVATED THE RIVER LEVELS IF EVERYTHING LINES UP. GUIDANCE IS SHOWING EXCELLENT MOISTURE TRANSPORT AND BEING TAPPED IN WITH THE GULF STREAM SEE NO REASON TO BELIEVE THAT FLOODING WILL NOT OCCUR...ESP WHEN PWAT VALUES ARE OVER 1.5 INCHES WHICH IS 4 STANDARD DEVIATIONS AWAY. BOTH AHEAD AND BEHIND THE FRONT...A VERY STRONG LLJ WILL DEVELOP WHICH WILL NOT ONLY AID IN THE MOISTURE TRANSPORT BUT WILL ALSO CREATE VERY GUSTY WINDS THROUGH THE PERIOD. WIND GUSTS OF 20 TO 30 MPH ARE EXPECTED AHEAD OF THE FRONT BUT PERHAPS EVEN STRONGER GUSTS COULD OCCUR AS 925MB WINDS SPEEDS STRENGTHEN TO 60-80KTS. THIS COULD RESULT IN A POSSIBLE WIND ADV IF WE MIX ALL THE WAY TO 925MB. LATEST BUFKIT SOUNDINGS ARE SHOWING THAT WE WILL BE JUST SHY...BUT SOMETHING TO MONITOR. VERY STRONG CAA WILL OCCUR AS THE FRONT PASSES THROUGH BY WED...WHICH COULD RESULT IN AN INCREASE OF WIND SPEEDS BEHIND THE FRONT. PERHAPS SPEEDS AROUND 20MPH AS 925 MB JET IS AROUND 30-40KTS. GUIDANCE INDICATES THAT TEMPS BEHIND THE FRONT DROP VERY QUICKLY ALLOWING FOR COLDER AIR TO RUSH INTO THE REGION. IF ANY PRECIP LINGERS BEHIND THE SYSTEM...WE COULD HAVE SOME P-TYPE ISSUES ESP ACROSS THE BERKSHIRES AND IN SOUTHERN NEW HAMPSHIRE. LASTLY WITH THE STRONG ONSHORE FLOW FROM THE SOUTH...WE WILL NEED TO WATCH FOR THE POTENTIAL FOR SOME MINOR SPLASHOVER ALONG THE SOUTH SHORE AND INTO NARRAGANSETT BAY. TIDES ARE SLOWLY INCREASING WITH HIGH ASTRONOMICAL TIDE PEAKING NEXT FRIDAY/SATURDAY. HOWEVER WE WOULD NEED CLOSE TO A 2FT SURGE INTO NARRAGANSETT BAY AND A 5 FT SURGE ALONG THE SOUTH COAST. YET THE BIGGEST CONCERN ACROSS THE SOUTH COASTLINE WOULD BE THE POTENTIAL WAVE ACTION AHEAD OF THE FRONT. AS ONE CAN SEE THERE IS A LOT OF HAZARDS THAT THIS STORM CAN POTENTIALLY DEVELOP. ALTHOUGH CONFIDENCE IS STILL A LITTLE UNCERTAIN...ESP SINCE THIS STORM IS STILL 4 DAYS AWAY...IT IS LOOKING LIKE A POTENT SPRING STORM WILL AFFECT THE EASTERN STATES EARLY NEXT WEEK. THURSDAY AND FRIDAY... STRONG HIGH PRESSURE WILL QUICKLY USHER INTO THE REGION BEHIND THE STALLED FRONT. TEMPERATURES WILL DROP WELL BELOW AVERAGE WITH HIGH JUST REACHING 50F. WE WILL NEED TO MONITOR THE FRONT FOR ANY POTENTIAL WAVES THAT COULD DEVELOP ALONG IT ON THURSDAY OR FRIDAY. RIGHT NOW BELIEVE THAT THE HIGH PRESSURE WILL WIN OUT...OVERALL HAVE A LOW CONFIDENCE. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE. TODAY...NORTHWEST WINDS DIMINISH BY AFTERNOON WITH POTENTIAL FOR SEA BREEZES ALL COASTS IN THE AFTERNOON. TONIGHT...VFR. SUNDAY...VFR. AREAS OF IFR CIGS/VSBYS IN FOG MAY MOVE ONTO THE SOUTH COAST/ISLANDS TOWARD EVENING. INCREASING SOUTHWEST WINDS AT 2000-3000 FEET WITH POTENTIAL OF 40-50 KNOTS. THIS WOULD BRING LOW LEVEL WIND SHEAR TO ALL AREAS. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. LOW CONFIDENCE IN TIMING OF SEA BREEZE. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY... SUNDAY NIGHT...MODERATE CONFIDENCE. VFR TO START WITH IFR CONDITIONS MOVING ACROSS THE SOUTH SHORELINE IN LOW CLOUDS/PATCHY FOG. MONDAY...MODERATE CONFIDENCE. LOCAL MVFR-IFR CIGS/VSBYS ALONG S COAST EARLY MON SHOULD IMPROVE...OTHERWISE VFR. S-SW WINDS GUSTING UP 25-35 KTS. TUESDAY-WEDNESDAY...LOW CONFIDENCE. EXPECT MVFR CONDITIONS TO DEVELOP FROM W-E DURING TUE IN RAIN SHOWERS. PERIODS OF HEAVY RAIN POSSIBLE TUE AFTERNOON/EVENING ACROSS CENTRAL AND WESTERN AREAS WITH AREAS OF IFR. PRECIP MAY MIX WITH LIGHT SNOW AND/OR SLEET ACROSS S NH/W MA BEFORE ENDING LATE TUE NIGHT OR WED MORNING. CONDITIONS SHOULD IMPROVE TO VFR FROM W-E DURING WED. && .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. SCA REMAINS POSTED FOR SOUTHERN OUTER WATERS AND RI WATERS DUE TO LEFTOVER 5-7 FT SEAS. OTHERWISE WINDS DIMINISH AS HIGH PRESSURE BUILDS OVER THE WATERS TODAY. AFTERNOON WINDS WILL BE LIGHT AND ALLOW FOR SEA BREEZES ALONG THE EAST AND SOUTH COASTS. TONIGHT AND SUNDAY...LIGHT SOUTH SOUTHWEST FLOW DEVELOPS TONIGHT AND INCREASES A LITTLE SUNDAY. SPEEDS SHOULD REMAIN BELOW 25 KNOTS MOST PLACES...BUT MAY APPROACH 25 KTS IN SPOTS LATE SUNDAY. THIS WIND WILL TRANSPORT HIGHER HUMIDITY AIR OVER THE COLDER OCEAN WATERS...WHICH SHOULD AN INCREASING CHANCE OF FOG AND LOW CLOUDS THROUGH SUNDAY. SEAS WILL DIMINISH BELOW 5 FEET TONIGHT...THEN BUILD AGAIN LATER ON SUNDAY. SCA HAS BEEN EXTENDED INTO EARLY TONIGHT...AND MAY EVENTUALLY BE NEEDED FOR LATER SUNDAY. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY... MONDAY...HIGH CONFIDENCE. AREAS OF FOG WILL DEVELOP LATE SUNDAY NIGHT AND MAY LINGER INTO MID-MORNING ON MONDAY. DURING THE DAY...EXPECT S-SW WINDS TO GUST UP TO 25 KTS DURING THE DAY. FOG WILL DEVELOP AGAIN MONDAY NIGHT. SCA WILL BE NEEDED. TUESDAY INTO WEDNESDAY...MODERATE CONFIDENCE. STRONG COLD FRONT WILL MOVE ACROSS THE WATERS TUESDAY INTO WEDNESDAY. EXPECT GUSTY WINDS AHEAD OF THE FRONT AND BEHIND THE FRONT DUE TO STRONG CAA. SEAS WILL BUILD IN RESPONSE AND MAY START RELAXING LATE WEDNESDAY. THERE IS A LOW PROBABILITY OF GALES TUESDAY EVENING INTO THE OVERNIGHT HOURS. && .HYDROLOGY... NERFC FORECASTS BRING LOWER CT RIVER FROM HARTFORD THROUGH MIDDLE HADDAM INTO MINOR FLOOD BEGINNING SUNDAY EVENING...BASED UPON WATER BEING ROUTED DOWNSTREAM. THOSE WITH INTERESTS ALONG LOWER REACHES OF CT RIVER SHOULD PAY ATTENTION TO THE LATEST FORECASTS. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM EDT SUNDAY FOR ANZ254>256. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 3 PM EDT THIS AFTERNOON FOR ANZ237. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM EDT THIS EVENING FOR ANZ235.
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&& $$ SYNOPSIS...WTB/DUNTEN NEAR TERM...WTB/KJC SHORT TERM...WTB LONG TERM...DUNTEN AVIATION...WTB/DUNTEN MARINE...WTB/DUNTEN HYDROLOGY...

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