949
FXUS61 KBOX 141121
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
721 AM EDT WED OCT 14 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES.
KEY MESSAGES
- ISOLATED SHOWER POSSIBLE TODAY, BUT DRIER OVERALL. DRY
THURSDAY WITH SEASONABLY COOL TEMPERATURES.
- LOW PRESSURE SYSTEM EXPECTED TO BRING RAIN FRIDAY INTO EARLY
SATURDAY. GUSTY NW WINDS AND BELOW NORMAL TEMPERATURES
EXPECTED TO BE LEFT IN ITS WAKE.
DISCUSSION
KEY MESSAGE 1...ISOLATED SHOWER POSSIBLE TODAY, BUT DRIER OVERALL.
DRY THURSDAY WITH SEASONABLY COOL TEMPERATURES.
LOW PRESSURE CENTERED OVER CENTRAL NY WILL CONTINUE TO TRACK EAST
INTO NORTHERN NEW ENGLAND THROUGH THE DAY TODAY. WITH THIS PASSING
LOW, ITS TRAILING COLD FRONT WILL CROSS OVER SOUTHERN NEW ENGLAND
AND HIGH PRESSURE WILL BUILD IN SLOWLY BEHIND IT. SKIES ARE EXPECTED
TO STEADILY CLEAR THROUGH THE DAY TODAY AS A RESULT. AN ISOLATED
SHOWER CANNOT BE RULED OUT THIS AFTERNOON GIVEN THE PASSAGE OF THIS
DISTURBANCE, AND LATEST CAMS DID HINT AT A LOW CHANCE FOR AN
ISOLATED SHOWER OR TWO TO DEVELOP.
LATEST MODEL SOUNDINGS CONTINUE TO INDICATE DECENT MIXING DURING THE
DAY TODAY, WHICH WILL LEND ITSELF TO GUSTY W WINDS UP TO 20-30 MPH,
THOUGH LOCALLY HIGHER GUSTS IN THE HIGHER TERRAIN CANNOT BE RULED
OUT. WITH THESE AFOREMENTIONED GUSTY WESTERLY WINDS, DOWNSLOPING
FLOW IS ANTICIPATED TODAY WHICH WILL COMBINE WITH WARMER
TEMPERATURES ALOFT TO SUPPORT A MUCH WARMER FALL DAY. 925 MB
TEMPERATURES ARE EXPECTED TO RANGE BETWEEN 16-18C, WITH THE SOUTHERN
COASTAL AREAS POSSIBLY REACHING 20C ALOFT. THOUGH TEMPERATURES ARE
NOT EXPECTED TO HIT 80F, HIGHS IN THE 70S TODAY WILL OVERSPREAD
SOUTHERN NEW ENGLAND, AND SOME SPOTS IN THE SOUTHERN CT RIVER VALLEY
AND SE MA COULD GET VERY CLOSE TO 80F. DESPITE THESE WARMER
TEMPERATURES, DEW POINTS WILL REMAIN COMFORTABLY IN THE 50S AND 60S.
HEADING INTO TONIGHT AND THURSDAY, HIGH PRESSURE STRONGLY TAKES HOLD
OF THE REGION ALONG WITH A SIGNIFICANTLY DRIER AIRMASS. PWATS FALL
TO AS LOW AS 0.2" AND WINDS SLACKEN CONSIDERABLY, BECOMING LIGHT TO
CALM. THE WARMER AIRMASS OVERHEAD TODAY SHIFTS OFF TO THE EAST AND
IS REPLACED BY A NOTABLY COOLER ONE WITH 925 MB TEMPERATURES FALLING
BELOW 10C. THIS WILL BE SUPPORTIVE OF COOLER LOWS TONIGHT AND A
COOLER DAY THURSDAY: LOWS WILL FALL INTO THE 40S AND LOW 50S, AND
HIGHS THURSDAY WILL TOP OUT IN THE LOW 60S.
KEY MESSAGE 2...LOW PRESSURE SYSTEM EXPECTED TO BRING RAIN FRIDAY
INTO EARLY SATURDAY. GUSTY NW WINDS AND BELOW NORMAL TEMPERATURES
EXPECTED TO BE LEFT IN ITS WAKE.
A STRONG NORTHERN STREAM SHORTWAVE TROUGH IS EXPECTED TO SHIFT
ACROSS THE GREAT LAKES AND INTO THE NORTHEAST FRIDAY INTO SATURDAY.
THE OVERALL CONSENSUS ACROSS THE DETERMINISTIC AND ENSEMBLE GUIDANCE
IS THAT THE SURFACE LOW SETS UP ACROSS WESTERN NY AND SOUTHEASTERN
ONTARIO BY FRIDAY MORNING, WITH RAIN MOVING INTO SOUTHERN NEW
ENGLAND AT THIS SAME TIME. AN UPPER LEVEL JET SETS UP NEAR SOUTHERN
NEW ENGLAND (AT 250 MB OVER THE REGION, THIS JET MAY REACH AROUND
120-150 KT BASED ON LATEST GUIDANCE), PROVIDING SUPPORT FOR BROAD
SYNOPTIC ASCENT. WITH THIS SETUP, AN ANOMALOUS MOISTURE PLUME WILL
BE ADVECTED IN FROM THE SW. NAEFS GUIDANCE HAS PWAT VALUES
APPROACHING 3 STANDARD DEVIATIONS ABOVE NORMAL OVER THE REGION BY
FRIDAY MORNING, AND IVT VALUES REACHING THE MAXIMUM OF THE CFSR
CLIMATOLOGY BY EARLY FRIDAY AFTERNOON. NOTABLY, TOO, TEMPERATURES
ALOFT WITH THIS PLUME ARE QUITE WARM, WITH 925 MB TEMPERATURES
BRIEFLY RETURNING TO AROUND 16-18C AND 850 MB TEMPERATURES TO AROUND
10C. ENSEMBLE GUIDANCE HAS A BIT MORE AGREEMENT THIS MORNING
REGARDING RAINFALL TOTALS, GENERALLY RANGING BETWEEN 0.4-0.7".
ACROSS ALL ENSEMBLES, SOME HIGHER PROBABILITIES OF TOTALS REACHING
OR EXCEEDING 1.0" EXIST OVER PARTS OF CENTRAL AND WESTERN MA,
ESPECIALLY TOWARDS THE BERKSHIRES. MEAN TOTALS ALSO TREND SLIGHTLY
HIGHER THERE ACROSS GUIDANCE, GENERALLY GETTING TO JUST UNDER AN
INCH. DETERMINISTIC GUIDANCE INDICATES SOME SIGNAL FOR LINES OF MORE
CONVECTIVE SHOWERS, BUT DETAILS REGARDING HOW MUCH MAY FALL WITHIN
THOSE AND WHERE THEY SET UP ARE STILL UNCERTAIN AT THIS TIME.
ASIDE FROM THE UPPER LEVEL JET, A SOUTHERLY LLJ IS SLATED TO SET UP
OVER THE REGION FRIDAY, WITH VALUES AT 925 MB RANGING BETWEEN 40-50
KT AT ITS MAXIMUM. IF MIXED WELL, WE COULD SEE SOME BREEZY OR GUSTY
SW WINDS. GUSTS COULD RANGE BETWEEN 25-35 MPH, WITH HIGHER GUSTS
POSSIBLE FOR THE CAPE AND ISLANDS, ESPECIALLY AS THE CORE OF THIS
JET SETS UP OVER THESE AREAS.
FOLLOWING THIS RAINFALL, A STRONG COLD FRONT IS EXPECTED TO PUSH
THROUGH THE REGION SATURDAY MORNING, KICKING OFF STRONG COLD AIR
ADVECTION UNDERNEATH MORE CYCLONIC FLOW. LATEST GUIDANCE INDICATES
925 MB TEMPERATURES SINKING BELOW 0C SATURDAY AS THIS PATTERN KICKS
OFF. PWATS FALL BELOW 0.25" ONCE MORE AS THIS DRY, COLD AIR SETS IN.
LOWS FRIDAY NIGHT FALL INTO THE 40S AND UPPER 30S, WITH THE HIGHER
ELEVATIONS LIKELY FALLING BELOW TO AT FREEZING. HIGHS SATURDAY MAY
STRUGGLE TO REACH THE LOW 50S ACROSS THE INTERIOR AND LOWS SATURDAY
NIGHT WILL LIKELY DIP BELOW FREEZING ACROSS THE REGION BASED ON THE
LATEST ENSEMBLE PROBABILITIES, WITH THE EXCEPTIONS BEING AREAS
CLOSEST TO THE COASTS AND URBAN AREAS. THOUGH, THOSE AREAS WILL
LIKELY BE SITTING JUST AROUND/ABOVE FREEZING OVERNIGHT. IN THE MIDST
OF THIS COLDER AIR, STRONG NW WINDS PREVAIL, GUSTING WELL INTO THE
30 MPH RANGE WITH SOME GUSTS TO 40 MPH NOT TO BE RULED OUT.
HIGH PRESSURE BUILDS IN SUNDAY AND A MORE SEASONABLY COOL AIRMASS
MOVES INTO THE REGION, AND THE TIGHTER GRADIENT BETWEEN THE STRONG
EXITING LOW AND APPROACHING HIGH PRESSURE SLACKENS. THIS WILL ALLOW
WINDS TO LET UP AS WELL, DIMINISHING SLIGHTLY HEADING INTO THE
SECOND HALF OF THE WEEKEND.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
12Z TAF UPDATE:
TODAY: HIGH CONFIDENCE.
WARM-FRONTAL IFR STRATUS AND FOG AT BED SHOULD TAKE LONGEST (BY
15Z) TO LIFT TO VFR, OTHERWISE VFR SHOULD GOVERN. WIDELY-SCT
LIGHT SHRA POSSIBLE 17-23Z FROM WEST TO EAST BUT COVERAGE TOO
LIMITED FOR A TAF MENTION. WINDS DRIVE MOST OF THE CHANGE
GROUPS, WITH SW WINDS 5 KT OR LESS NORTH OF THE MASS PIKE,
INCREASING TO AROUND 10-13 KT WITH GUSTS TO 22 KT SOUTH.
WINDSHIFT TO W BETWEEN 15-17Z AROUND 10 KT, THEN BECOMING NW
AROUND 10 KT BETWEEN 22-00Z THURS.
TONIGHT: HIGH CONFIDENCE.
VFR. NW WINDS INCREASE TO AROUND 10-12 KT, WITH GUSTS 20-25 KT
FOR MOST DEVELOPING 02-04; UPWARDS OF 25-28 KT GUSTS FOR THE
EASTERN MA AIRPORTS AND THE CAPE.
THURSDAY...HIGH CONFIDENCE.
VFR. WINDS DIMINISH GREATLY WITH HIGH PRESSURE SETTLING
OVERHEAD, BECOMING LIGHT AND VARIABLE TO CALM.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. BOS IS VFR, ALTHOUGH
OWD STILL HAS LIFR MIST/FOG. EXPECT THAT TO ERODE AT OWD BY 14Z.
WINDSHIFT TO W AROUND 10 KT BY 16Z, THEN TURNING NW AROUND 10 KT
BY 00Z, INCREASING TO 12-14 KT / GUSTS TO 25 KT OVERNIGHT. SLOW
CESSATION INTO THURS AM.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF. WINDSHIFT TO W AROUND
10 KT BY 15Z, THEN TURNING NW AROUND 10 KT BY 22-23Z, WITH GUSTS
TO 20 KT DEVELOPING OVERNIGHT.
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...
THURSDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. BREEZY.
CHANCE SHRA.
FRIDAY: MVFR/IFR CONDITIONS POSSIBLE. WINDY WITH LOCAL GUSTS UP
TO 30 KT. SHRA.
FRIDAY NIGHT: MAINLY VFR, WITH LOCAL MVFR POSSIBLE. WINDY WITH
GUSTS UP TO 35 KT. SHRA LIKELY.
SATURDAY: VFR. WINDY WITH GUSTS UP TO 35 KT.
SATURDAY NIGHT: VFR. WINDY WITH LOCAL GUSTS UP TO 30 KT.
SUNDAY: VFR. BREEZY.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH THURSDAY...HIGH CONFIDENCE.
WINDS WILL TURN MORE W/NW TODAY, BUT STILL CONTINUE IN THE
20-25KT RANGE THROUGH MID-DAY. WINDS START TO DIMINISH LATER IN
THE AFTERNOON INTO EVENING. THIS WILL HELP TO PUSH WAVES UP TO
AROUND 5-6FT, ESPECIALLY FURTHER OFFSHORE. LOOKING TOWARD
THURSDAY, WINDS AND SEAS WILL DIMINISH AS A RIDGE OF HIGH
PRESSURE MOVES ACROSS THE REGION.
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...
THURSDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT.
FRIDAY: MODERATE RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS
UP TO 30 KT. AREAS OF ROUGH SEAS. RAIN SHOWERS, SLIGHT CHANCE
OF THUNDERSTORMS.
FRIDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 35 KT. ROUGH SEAS
UP TO 13 FT. RAIN SHOWERS.
SATURDAY: STRONG WINDS WITH GUSTS UP TO 35 KT. ROUGH SEAS UP TO
13 FT. SLIGHT CHANCE OF RAIN SHOWERS.
SATURDAY NIGHT: STRONG WINDS WITH GUSTS UP TO 35 KT. ROUGH SEAS
UP TO 12 FT.
SUNDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 25 KT. LOCAL ROUGH SEAS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ231>235-237.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ250.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ254>256.
DISCUSSION...HRENCECIN
AVIATION...LOCONTO/HRENCECIN
MARINE...HRENCECIN/MENSCH/NASH
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