Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 181918 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 318 PM EDT MON AUG 18 2014 .SYNOPSIS... REMAINING DRY AND SEASONABLE INTO WEDNESDAY FOLLOWED BY A COOLER PATTERN THURSDAY AND FRIDAY WITH THE INCREASE IN CLOUDS AND THE CHANCE OF SHOWERS /MAINLY OVER WESTERN NEW ENGLAND/. UNCERTAINTY IN THE FORECAST OVER THE WEEKEND WITH REGARDS TO THE PROXIMITY OF A COASTAL LOW OFF OF NEW ENGLAND. && .NEAR TERM /THROUGH TONIGHT/... INTO EVENING... WILL SEE NW-WINDS BEGIN TO DIMINISH AS SEA-BREEZES ALONG THE IMMEDIATE SHORELINE WASHOUT. SCATTERED TO BROKEN CLOUD DECKS WILL BEGIN TO DISSIPATE MAKING WAY FOR MOSTLY CLEAR CONDITIONS. TONIGHT... WEAK SURFACE HIGH PRESSURE SETTLES ACROSS THE REGION WITH DRY AIR AND SUBSIDENCE ALOFT. EXPECT MOSTLY CLEAR CONDITIONS WITH LIGHT AND VARIABLE WINDS. WHILE SOME SCATTERED MID-LEVEL CLOUDS ARE POSSIBLE OVER SW NEW ENGLAND...OVERALL EXPECTING A PRETTY CHILLY NIGHT WITH LOWS INTO THE LOW-50S. A FEW SPOTS WHICH CLIMATOLOGICALLY RADIATE WELL /I.E. SHELTERED VALLEYS WITHIN THE CT-RIVER VALLEY...SW MA...AND MARTHAS VINEYARD/ COULD SEE LOWS AROUND THE UPPER-40S. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... TUESDAY... GOOD MODEL AGREEMENT OF H5 RIDGE ENHANCEMENT W OF THE REGION AHEAD OF A SYNOPTIC DISTURBANCE ACROSS THE GREAT LAKES. THIS WILL RESULT IN SURFACE HIGH PRESSURE REMAINING IN CONTROL WITH CONTINUED DRY AIR AND SUBSIDENCE ALOFT...AS H85 TEMPERATURES WARM A COUPLE OF DEGREES TO +10-12C. WEAK PRESSURE GRADIENT ACROSS THE REGION SHOULD ALLOW FOR SEA- BREEZES ALONG THE SHORES. SCATTERED DIURNAL CUMULUS ANTICIPATED WITH DAYTIME HEATING. WITH MID-LEVEL TEMPERATURES WARMING...ANTICIPATE MORE SEASONABLE CONDITIONS WITH HIGHS AROUND THE UPPER-70S. TUESDAY NIGHT... WILL HOLD THE MID-ATLANTIC LOW PRESSURE DISTURBANCE S OF NEW ENGLAND...PREVAILING WITH A W TO E MOTION THROUGH THE QUASI-ZONAL FLOW. THIS REMOVES THE 18.09Z SREF FROM CONSIDERATION. FIGURE WITH THE MULTITUDE OF SYSTEMS SURROUNDING THE NE-CONUS SHOULD KEEP THE REGION BENEATH CONTINUED SUBSIDENCE AND DRIER AIR. ANTICIPATING A QUIET EVENING. PERHAPS SOME MID- TO HIGH-LEVEL CLOUDS FILTER ACROSS THE FORECAST AREA FROM THE REGION OF DISTURBED WEATHER S. OTHERWISE LIGHT WINDS AND LIKELY ANOTHER OVERNIGHT PERIOD OF CHILLY TEMPERATURES. LOWS AROUND THE MID-50S WITH A FEW LOCATIONS THAT RADIATE OUT EFFECTIVELY FALLING INTO THE UPPER-40S. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... HIGHLIGHTS... * QUIET WEATHER EXPECTED THROUGH MUCH OF THE WORK WEEK * UNCERTAINTY INCREASES OVER THE WEEKEND WITH SHOWERS POSSIBLE MODELS ARE IN GOOD AGREEMENT THROUGH MUCH OF THE WORK WEEK ON THE GENERAL PATTERN AS WELL AS THE SENSIBLE WEATHER. FOR THE WEEKEND AND INTO EARLY NEXT WEEK...MODELS DIVERGE AS THE GFS TAKES ON A MORE BLOCKY UPPER LEVEL PATTERN AND THE ECMWF REMAINS A BIT MORE PROGRESSIVE. THIS RESULTS IN SOME UNSETTLED WEATHER OVER THE WEEKEND. BOTH MODELS HAVE AN UPPER LEVEL TROUGH OVER THE REGION THROUGH THE WORK WEEK WHICH RESULTS IN THE COOLER...LESS SEASONABLE WEATHER. THEN FOR THE WEEKEND...THE ECMWF MOVES THE TROUGH OFFSHORE ALLOWING FOR A MORE PROGRESSIVE ZONAL FLOW WHILE THE GFS KEEPS THE TROUGH ANCHORED OVER THE NORTHEAST. THIS ALSO CREATES CHANGES IN THE SURFACE PATTERN. HIGH PRESSURE IN QUEBEC THROUGH MUCH OF THE WEEK SINKS SLOWLY SOUTHWARD THROUGH THE WEEKEND ON THE ECMWF PUSHING A SERIES OF LOW PRESSURE SYSTEMS MOVING OFF THE MID-ATLANTIC COAST WELL OFFSHORE. THE HIGH IS EVENTUALLY PUSHED EASTWARD EARLY NEXT WEEK ALLOWING A COLD FRONT TO PUSH THROUGH SOUTHERN NEW ENGLAND. THE GFS MOVES THE HIGH PRESSURE EASTWARD THIS WEEKEND INSTEAD WHICH ALLOWS LOW PRESSURE TO MOVE UP THE COAST JUST OUTSIDE OF THE 40/70 BENCHMARK... BRINGING RAIN TO MUCH OF THE REGION SUNDAY. GIVEN THIS IS AT THE END OF THE LONG TERM FORECAST...WILL STICK WITH A BLEND OF GUIDANCE WITH SLIGHT CHANCE TO LOW END CHANCE POPS FOR THE BEGINNING OF NEXT WEEK AND SEE WHERE FUTURE RUNS OF THE MODELS TAKE US. WEDNESDAY THROUGH FRIDAY...UPPER LEVEL TROUGH STICKS ACROSS THE NORTHEAST WITH HIGH PRESSURE IN QUEBEC SINKING INTO SOUTHERN NEW ENGLAND. SEASONABLE TO JUST BELOW NORMAL TEMPERATURES ARE EXPECTED ALONG WITH DRY WEATHER. THERE IS A LOW PROBABILITY THAT A FEW SHOWERS MAY BLEED INTO WESTERN NEW ENGLAND ON WEDNESDAY...BUT IT IS EXPECTED THAT MOST OF THE SHOWER ACTIVITY WILL REMAIN IN NEW YORK STATE. THIS WEEKEND INTO EARLY NEXT WEEK...AS STATED ABOVE THIS IS WHERE THE BULK OF THE UNCERTAINTY IS. SATURDAY SHOULD STILL BE UNDER THE INFLUENCE OF HIGH PRESSURE WITH SEASONABLY COOL TEMPERATURES AND DRY WEATHER. SUNDAY AND MONDAY HAVE THE GREATEST LIKELIHOOD OF SHOWERS OR RAIN AS EITHER A COLD FRONT OR A COASTAL LOW BRING MOISTURE TO THE REGION. TEMPERATURES SHOULD START TO WARM A FEW DEGREES THROUGH THIS PERIOD. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...THROUGH TUESDAY NIGHT...HIGH CONFIDENCE. 18Z UPDATE... VFR. NW WINDS WITH GUSTS UP TO 20 KTS ACROSS THE INTERIOR. SEA- BREEZE ACTIVITY ALONG THE IMMEDIATE SHORELINES FROM NOW UNTIL 22Z. WINDS LIKELY TO BE LIGHT AND VARIABLE WITH SEA-BREEZE INCURSION. SCT-BKN CIGS AROUND 5-6 KFT. OVERNIGHT...LIGHT N WINDS ANTICIPATED UNDER SKC. PATCHY MVFR-IFR GROUND FOG IS POSSIBLE. LIGHT AND VARIABLE WINDS CONTINUE INTO TUESDAY ALLOWING SEA-BREEZE ENCROACHMENT BEGINNING AROUND 14Z... WASHING OUT INTO OVERNIGHT HOURS. SCT CIGS AROUND 5-6 KFT DURING THE DAY...MAINLY SKC INTO WEDNESDAY MORNING WITH SOME FILTERING MID- TO HIGH-LEVEL CLOUDS. KBOS TERMINAL...MODERATE CONFIDENCE. WEAKENING NW-FLOW IN AND AROUND THE TERMINAL INDICATES POTENTIAL SEA-BREEZE SETUP TOWARDS 20Z. SEA-BREEZE MAY STRUGGLE TO REACH THE TERMINAL...PERHAPS PARKING OVER THE E-END OF RUNWAYS. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...WEDNESDAY THROUGH SATURDAY... WEDNESDAY THROUGH SATURDAY...MODERATE CONFIDENCE. VFR. LOW PROBABILITY OF PATCHY MVFR/IFR FOG EACH NIGHT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM...THROUGH TUESDAY NIGHT...HIGH CONFIDENCE. AN OVERALL THEME OF HIGH PRESSURE AND QUIET BOATING WEATHER. S/SW-FLOW WILL DIMINISH INTO EVENING AS WINDS TURN OUT OF THE N. SEA-BREEZES WASH-OUT ALONG THE NEAR-SHORES. WILL SEE THE RETURN OF SE-WINDS TUESDAY TURNING N/NE INTO THE EVENING PERIOD... STRENGTHENING 10-15 KTS IN RESPONSE TO A STORM SWEEPING OUT TO SEA OFF THE MID-ATLANTIC. OUTLOOK...WEDNESDAY THROUGH SATURDAY... MODERATE TO HIGH CONFIDENCE. QUIET BOATING WEATHER IS EXPECTED THROUGH MUCH OF THE PERIOD WITH HIGH PRESSURE ACROSS THE REGION. LOW PROBABILITY OF PATCHY OVERNIGHT FOG LIMITING VISIBILITIES. SEAS MAY INCREASE ON THE OUTER WATERS SATURDAY AS AN OCEAN STORM PASSES WELL EAST OF THE SOUTHERN NEW ENGLAND WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...RLG/SIPPRELL NEAR TERM...SIPPRELL SHORT TERM...SIPPRELL LONG TERM...RLG AVIATION...RLG/SIPPRELL MARINE...RLG/SIPPRELL

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