Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 152032 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 432 PM EDT TUE APR 15 2014 .SYNOPSIS...
-- Changed Discussion --
SHARP COLD FRONT PUSHING ACROSS NEW ENGLAND OVERNIGHT WILL BRING A MIX OF STRONG GUSTY WINDS...HEAVY RAIN...AND EVEN A BRIEF CHANGE TO A WINTRY MIX BEFORE ENDING EARLY ON WEDNESDAY. HIGH PRESSURE IMMEDIATE FOLLOWING BRINGING DRY BUT UNSEASONABLE CONDITIONS FOR WEDNESDAY INTO WEDNESDAY NIGHT. DRY WEATHER CONTINUES THURSDAY INTO THE FIRST PART OF FRIDAY WITH MODERATING AFTERNOON TEMPS INLAND... BUT REMAINING CHILLY ALONG THE COAST. LOW PRESSURE MAY BRING A ROUND OR TWO OF RAIN SHOWERS SOMETIME FRIDAY NIGHT INTO SATURDAY THEN DRY AND COOLER SUNDAY/MONDAY.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --
430 PM UPDATE... COLD FRONT NOW PUSHING INTO WESTERN NEW ENGLAND. WIDESPREAD RAIN WITH EMBEDDED HEAVIER SHOWERS LENDING TO NUMEROUS OBSERVATIONS OF SOUTHERLY WIND GUSTS IN EXCESS OF 40 MPH WITH ISOLATED GUSTS UP TO AROUND 50 MPH. THE PROGRESSIVE NATURE OF THE RAIN IS LENDING TO A QUARTER- TO HALF-INCH PER HOUR RAINFALL AMOUNTS...NOT SO MUCH AN ISSUE TOWARDS FLASH FLOODING...BUT ENOUGH OVER THE COURSE OF TODAY INTO THIS EVENING TO LEND TO RIVER AND URBAN/POOR DRAINAGE FLOODING. THREATS AND ASSOCIATED IMPACTS ARE OUTLINED BELOW: HEAVY RAIN/FLOODING... FLOOD WARNINGS HAVE BEEN ISSUED FOR MULTIPLE POINTS ALONG THE CONNECTICUT RIVER BASIN WITH THE EXPECTATION OF MINOR RIVER FLOODING...PERHAPS MODERATE FLOODING AT MIDDLE HADDAM. SUB-TROPICAL MOISTURE WITH ASSOCIATED PRECIPITABLE WATER VALUES IN EXCESS OF 1.5-INCHES SURGING NORTH WITH THE AMPLIFYING LOW-LEVEL FLOW /70-80 KTS PRESENTLY PER WSR-88D VERTICAL WIND PROFILERS/ IS ANOMALOUSLY HIGH ON THE ORDER OF 3-4 STANDARD DEVIATIONS ABOVE NORMAL. CONVERGENT AHEAD OF THE FRONT AND ALONG THE NOSE OF THE LOW- LEVEL-JET...MOISTURE IS UNDERGOING BOTH FRONTOGENETICAL LIFT AND STRONG DEEP-LAYER ASCENT BENEATH AN AREA OF STRONG UPPER-LEVEL DIVERGENCE PER RRQ. THIS IS LENDING TO WIDESPREAD RAIN WITH EMBEDDED HEAVIER SHOWERS AND EVEN THE POSSIBILITY OF ISOLATED THUNDERSTORMS /ESPECIALLY IMMEDIATELY AHEAD OF THE COLD FRONT OVER NJ INTO THE LOWER HUDSON VALLEY TOWARDS THE BERKSHIRES/. WHILE RAINFALL RATES HAVE BEEN ANYWHERE FROM A QUARTER TO HALF- AN-INCH PER HOUR...THE CUMULATIVE RAINFALL AMOUNTS ARE EXPECTED TO BE AROUND 2 INCHES WITH LOCALLY HIGHER AMOUNTS AROUND 3 INCHES IN A TIME-FRAME ROUGHLY AROUND 6-HOURS. THUS THE FLOOD WATCH CONTINUES. THE BASIS FOR THE FLOOD WATCH CONTINUES TO BE A FOCUS UPON ALREADY SWOLLEN RIVERS FROM UPSTREAM SNOWMELT TAKING ON ADDITIONAL WATER GOING INTO MINOR FLOODING...POSSIBLY INTO MODERATE FLOOD FOR THE CONNECTICUT RIVER AT MIDDLE HADDAM. RIVER BASINS OF CONCERN INCLUDE CONNECTICUT/MERRIMACK/PAWCATUCK. ALSO ANTICIPATE IMPACTS TO LOCAL STREAMS/CREEKS/TRIBUTARIES... ESPECIALLY THOSE THAT ARE NARROWER AND FLASHIER. THOSE WITH INTERESTS ALONG AREA RIVERS SHOULD PAY ATTENTION TO THE LATEST FORECASTS AND CURRENT WATER LEVELS. THE FLOOD WATCH ALSO INCLUDES URBAN AND POOR DRAINAGE ISSUES FOR THE DRIVE-HOME COMMUTE PRESENTLY ONGOING FOR ALL ROADWAYS ACROSS SOUTHERN NEW ENGLAND. PONDING OF WATER THE BIGGEST CONCERN. PLEASE SEE THE COASTAL FLOODING SECTION BELOW FOR COASTAL FLOOD THREATS. WINDS... SEVERAL LOCATIONS ACROSS CENTRAL/EASTERN NEW ENGLAND OBSERVING WIND GUSTS IN EXCESS OF 40 KTS /46 MPH/. WSR-88D VERTICAL WIND PROFILERS SHOWING WINDS AT H925 AMPLIFYING TO 70 KTS. INCREASING AREAL COVERAGE OF RAIN WITH EMBEDDED HEAVIER SHOWERS AIDING IN THE PRECIP-DRAG / MECHANICAL MIXING OF FASTER MOMENTUM ALOFT DOWN TO THE SURFACE. SHOULD SEE THESE WINDS CONTINUE INTO THE EVENING HOURS. WIND ADVISORIES CONTINUE ACCORDINGLY. THOSE TRAVELING OVER BRIDGES /THINKING THE SAGAMORE AND BOURNE/ SHOULD BE AWARE OF FIERCE CROSSWINDS. GUSTS IN EXCESS OF 50 MPH WILL BE POSSIBLE. ALREADY RECEIVING NUMEROUS REPORTS OF TREES AND WIRES DOWN...BLOWN TRANSFORMERS AND POWER OUTAGES. THESE IMPACTS AND THREATS WILL CONTINUE OVER THE NEXT SEVERAL HOURS AHEAD OF THE COLD FRONT SWEEPING THROUGH THE REGION. WINTRY MIX/FLASH FREEZE POTENTIAL... TEMPERATURES QUICKLY FALLING IMMEDIATELY BEHIND THE COLD FRONT AS WINDS BACK OUT OF THE WEST. ALREADY TEMPERATURES IN THE 30S ARE ENCROACHING INTO THE HUDSON RIVER VALLEY REGION. EXPECTING THIS COLD AIR TO SURGE INTO THE REGION DURING THE OVERNIGHT HOURS... MAINLY AROUND AND AFTER MIDNIGHT. CONSIDERING THE STRONG DYNAMICS AND LIFT TO THE REAR OF THE COLD FRONT...THERE IS THE POTENTIAL FOR LINGERING PRECIPITATION WITHIN THE SHALLOW COLD-AIR MASS IN THE FORM OF A WINTRY MIX. THUS A BRIEF CHANGEOVER TO A SNOW/SLEET MIX IS POSSIBLE...MAINLY ACROSS INTERIOR PORTIONS OF NEW ENGLAND AND ESPECIALLY NORTH OF THE ROUTE-2 CORRIDOR INCORPORATING NORTHERN MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE. LIKELY TO SEE AN INCREASE IN LIKELIHOOD ALONG WESTERN SLOPES OF HIGHER TERRAIN. ANY ACCUMULATIONS WILL BE LIGHT AROUND A TRACE TO PERHAPS A TENTH OR TWO...ENOUGH TO MAKE FOR SLIPPERY CONDITIONS. DRIER AIR WILL WORK INTO THE REAR OF THE STORM RESULTING IN THE BACK EDGE OF PRECIP TO DISSIPATE. THIS DRIER AIR CAN BE SEEN WITHIN THE MID-LEVELS PER WATER-VAPOR IMAGERY...BUT SHOULD ALSO SEE THIS DRY AIR AT THE SURFACE. THUS IT IS A QUESTION AS TO WHETHER WET SURFACES WILL FREEZE AHEAD OF EVAPORATING. EITHER WHICH WAY...THERE IS THE POTENTIAL FOR BLACK-ICE AND SLIPPERY CONDITIONS THAT MAY EXIST FOR THE WEDNESDAY MORNING COMMUTE.
-- End Changed Discussion --
&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
-- Changed Discussion --
WEDNESDAY... AN UNSEASONABLY CHILLY AIRMASS WILL CONTINUE TO WORK INTO THE REGION AS HIGH PRESSURE BUILDS IN FROM THE WEST. ANY LEFT OVER PRECIP SHOULD EXIT THE CAPE/ISLANDS BY MID-MORNING AT THE LASTEST AS THE COLD FRONT WILL BE WELL OFFSHORE. WESTERLY WINDS CONTINUE TO GUST BETWEEN 30 AND 40 MPH DURING THE MORNING...BUT WILL DIMINISH DURING THE AFTERNOON. THIS AIDED BY ANOMALOUSLY COLD H85 TEMPS FOR THIS TIME OF YEAR BETWEEN -6C AND -10C ALLOWING FOR EFFECTIVE BOUNDARY LAYER MIXING. THOUGH WITH RESPECT TO TEMPERATURES...PLENTY OF STRONG APRIL SUNSHINE WILL OFFSET COLDER AIR ALOFT TO SOME DEGREE. ALL IN ALL...MUCH OF THE REGION SHOULD SEE HIGHS RECOVER WELL INTO THE 40S DURING THE AFTERNOON.
-- End Changed Discussion --
&& .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * DRY BUT UNSEASONABLY CHILLY WED NIGHT * DRY WEATHER CONTINUES INTO FRI AND BECOMING MILDER INLAND * A PERIOD OF SHOWERS POSSIBLE FRI NIGHT INTO SAT BUT LOW CONFIDENCE AN ACTIVE AND SURPRESSED NORTHERN STREAM JET THIS PERIOD WILL RESULT IN TEMPERATURES AT OR COOLER THAN NORMAL ALONG WITH A FEW CHANCES OF SHOWERS. VERY TYPICAL PATTERN FOR MID APRIL. DAILY DETAILS... WEDNESDAY NIGHT... CHILLY AIRMASS OVER THE REGION ALONG WITH MAINLY CLEAR SKIES AND DIMINISHING WINDS. THIS WILL RESULT IN COLD TEMPS OUTSIDE OF THE URBAN AREAS WITH MOST LOCATIONS IN THE 20S! THURSDAY AND FRIDAY... STRONG /1044 MB!/ HIGH PRESSURE ADVECTS INTO THE CANADIAN MARITIMES. THIS WILL EVOLVE INTO A COOL MARITIME AIRMASS FOR SOUTHERN NEW ENGLAND WITH LARGE TEMP DIFFERENCES FROM THE COAST TO INLAND. ACROSS EASTERN MA THE VERY CHILLY OCEAN WATERS WITH SSTS IN THE L40S WILL ACT LIKE A SNOWCOVER AND ENHANCE THIS COOL MARITIME AIRMASS. CHILLY ONSHORE WINDS WILL ADVECT THIS VERY COOL AND SHALLOW MARITIME AIRMASS INTO THE COASTAL PLAIN. THEREFORE ONLY EXPECTING HIGHS IN THE 40S OVER EASTERN MA...MEANWHILE STRONG APRIL SUN HEATS UP THE INTERIOR INTO THE 50S. AIRMASS CONTINUES TO MODIFY FRI WITH HIGHS 45- 50 EASTERN MA AND 55-60 WELL INLAND. FRIDAY NIGHT AND SATURDAY... MODELS CONTINUE TO STRUGGLE ON AMPLITUDE AND INTERACTION OF NORTHERN AND SOUTHERN STREAM WAVES. 12Z GFS REMAINS MORE ROBUST AND PHASING THAN THE 12Z ECMWF. THUS THE GFS IS THE WETTER SOLUTION OF THE TWO. ENSEMBLES INDICATE MORE STREAM SEPARATION AND ARE SLOWER PHASING THE STREAMS BUT THIS IS SOMEWHAT TYPICAL GIVEN THE LOWER RESOLUTION OF THE ENSEMBLES. TEMPS LIKELY REMAIN NEAR NORMAL...HIGHS IN THE 50S. SUNDAY/MONDAY/TUESDAY... AS EXPECTED LOTS OF TIMING ISSUES HERE GIVEN THE FAST FLOW ACROSS THE NORTHERN STATES. GIVEN THIS FLOW REGIME AND TIME RANGE HERE WILL FOLLOW A MODEL BLEND WHICH YIELDS TEMPS NEAR NORMAL AND A RISK OF SHOWERS IN THE MON NIGHT/TUE TIME FRAME. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --
LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH WEDNESDAY/...MODERATE CONFIDENCE. IFR-LIFR CIGS/VSBYS WITH +RA CONTINUING THROUGH THE EVENING. STRONG S WINDS CONTINUING WITH GUSTS IN EXCESS OF 40 KTS WITH A FEW LOCATIONS UP TO AROUND 50 KTS /ESPECIALLY FOR E-S MA AND RI/. LLWS IMPACTS OVER ALL TERMINALS WITH 60-70 KT 2 KFT AGL. COLD FRONT PUSHES THROUGH THE TERMINALS AROUND MIDNIGHT. WILL SEE WINDS BACK WEST REMAINING GUSTY UP TO 40 KTS. CONDITIONS QUICKLY IMPROVING TO VFR. MAY SEE RAIN TRANSITION TO SNOW/SLEET BRIEFLY WITH MINOR ACCUMS. BEST CHANCES OVER NW MA INTO S NH. PRECIP COMING TO AN END AS WINDS DIMINISH THROUGH THE DAY WEDNESDAY. KBOS TERMINAL...MODERATE CONFIDENCE. KBDL TERMINAL...MODERATE CONFIDENCE. OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY... WEDNESDAY NIGHT THRU FRIDAY...VFR VSBYS LIKELY WITH MVFR CIGS POSSIBLE...HIGHEST PROBABILITY ACROSS RI AND EASTERN MA. FRIDAY NIGHT INTO SATURDAY...MVFR IN SCATTERED SHOWERS POSSIBLE BUT CONFIDENCE IS VERY LOW. SUNDAY...IMPROVING TREND WITH VFR LIKELY ALONG WITH INCREASING NW WINDS.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH WEDNESDAY/...MODERATE CONFIDENCE. S WINDS OVER THE WATERS GUSTING IN EXCESS OF GALE FORCE THROUGH THE EVENING WITH WAVES OF 10 TO 12 FEET ON THE OUTER WATERS. RAIN AND FOG AHEAD OF THE FRONT WILL NET VISIBILITY ISSUES OVER THE WATERS DOWN TO A MILE OR TWO AT TIMES. THERE IS THE POSSIBILITY OF ISOLATED THUNDERSTORMS OVER THE SOUTH WATERS. COLD FRONT SWEEPS THE WATERS AROUND MIDNIGHT BEHIND WHICH WINDS WILL BACK OUT OF THE WEST REMAINING GUSTY UP TO 40 KTS. CONDITIONS CLEARING QUICKLY AS WINDS DIMINISH THROUGH THE DAY WEDNESDAY. WAVE ENERGY WILL SLOWLY DIMINISH...SO WHILE GALES CONCLUDE...SMALL CRAFT ADVISORIES WILL LIKELY BE NECESSARY. OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY... WED NIGHT THRU FRI...TREND HERE WILL BE DECREASING SOUTHERLY SWELLS WITH INCREASING ENE WIND WAVES. MAINLY DRY WITH MARITIME AIRMASS OVER THE WATERS COURTSEY OF 1040 MB HIGH ACROSS NEWFOUNDLAND. FRI NIGHT AND SAT...LOW CONFIDENCE FORECAST WITH LOW PRES APPROACHING FROM THE SOUTH AND ANOTHER FROM THE GREAT LAKES. DILEMMA WILL BE HOW MUCH SEPARATION BETWEEN THESE SYSTEMS OR IF LOWS WILL MERGE INTO ONE STRONGER SYSTEM. STILL TOO EARLY TO SAY. SUNDAY...IMPROVING TRENDS WITH LOW PRES STRENGTHENING WELL EAST OF NEW ENGLAND FOLLOWED BY A MODEST NW WIND.
-- End Changed Discussion --
&& .TIDES/COASTAL FLOODING...
-- Changed Discussion --
STRONG SOUTHERLY WINDS OVER THE WATERS GUSTING 30 TO 40 MPH WILL YIELD AN AVERAGE 1.5 FOOT SURGE ALONG THE SOUTH COAST. COMBINED WITH HIGH TIDE AROUND 9-10 PM /NOT ASTRONOMICALLY HIGH/...THERE IS THE POSSIBILITY OF SPLASHOVER ALONG LOW-LYING AREAS. A COASTAL FLOOD STATEMENT HAS BEEN ISSUED ACCORDINGLY TO ACCOUNT FOR THE THREAT AND IMPACTS.
-- End Changed Discussion --
&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR CTZ002>004. MA...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR MAZ002>021-026. WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MAZ004>007- 012>024-026. NH...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR NHZ011-012-015. RI...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR RIZ001>007. WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR RIZ001>008. MARINE...GALE WARNING UNTIL NOON EDT WEDNESDAY FOR ANZ230>234-236-250- 251. GALE WARNING UNTIL 10 AM EDT WEDNESDAY FOR ANZ235-237-256. GALE WARNING UNTIL 2 PM EDT WEDNESDAY FOR ANZ254-255. && $$ SYNOPSIS...NOCERA/SIPPRELL NEAR TERM...SIPPRELL SHORT TERM...SIPPRELL LONG TERM...NOCERA AVIATION...SIPPRELL MARINE...NOCERA TIDES/COASTAL FLOODING...SIPPRELL

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