459
FXUS61 KBOX 291047
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
647 AM EDT THU MAY 29 2025
SYNOPSIS
SHOWERS CONTINUE INTO THURSDAY AS WEAK LOW PRESSURE PASSES OFFSHORE.
ANOTHER ROUND OF SHOWERS EXPECTED FOR THE FIRST PART OF THE WEEKEND
AS A LOW PRESSURE CENTER TRACKS THROUGH NEW ENGLAND. COOLER AND DRY
WEATHER FOLLOWS SUNDAY INTO MONDAY, UNCERTAINTY WITH EARLY TO MIDDLE
PART OF NEXT WEEK IN TERMS OF TEMPERATURES, BUT DOES TREND
DRIER.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
* COOLER THU WITH SHOWERS FOCUSED IN RI AND EASTERN MA.
SHOWERS CONTINUE TO IMPACT ALL OF SOUTHERN NEW ENGLAND EARLY THIS
MORNING AS A WEAK SURFACE LOW MOVES TOWARD LONG ISLAND BEFORE
CROSSING OUR REGION LATER TODAY. THIS WILL PLACE A WEAK LOW LEVEL
JET OVER SOUTHEAST MA AND RI HELPING SHOWERS TO PERSIST HERE THROUGH
THE LATE MORNING/EARLY AFTERNOON EVEN AS DRIER AIR LEADS TO TAPERING
OFF OF WET WEATHER FOR WESTERN AREAS. EVEN SO, SKIES WILL BE SLOW TO
CLEAR AS LOW LEVEL MOISTURE REMAINS TRAPPED BENEATH AN INVERSION
EVEN HAS DRY AIR MOVES IN AT THE MID AND UPPER LEVELS. EVENTUALLY,
THOUGH, WE'LL SEE A DECREASE IN LOW CLOUDS AS A SHIFT TO W/SW FLOW
BRIEFLY BRINGS IN SOME DRIER LOW LEVEL AIR. THIS WILL BE MOST LIKELY
IN WESTERN MA/CT WHICH STANDS THE BEST CHANCE OF SOME BREAKS IN THE
CLOUDS IN THE EVENING BEFORE SATURATION RETURNS AT THE SURFACE
PERHAPS LEADING TO PATCHY DRIZZLE OVERNIGHT INTO FRIDAY AS A WEAK
TROUGH MOVES OVERHEAD.
SHORT TERM /FRIDAY/
KEY MESSAGE:
* REMAINING CLOUDY, PERHAPS A SPOT SHOWER.
PLENTY OF LOW LEVEL MOISTURE LINGERS THU NIGHT SO CLOUDS SHOULD
REMAIN LOCKED IN, ESPECIALLY WITH BROAD W/SW FLOW ALOFT AND A
WEAK SURFACE TROUGH MOVING THROUGH. THERE MAY BE ENOUGH WEAK
LIFT TO SUPPORT A BRIEF SHOWER OR EVEN PATCHY DRIZZLE.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
KEY MESSAGES:
* RAIN RETURNS FRIDAY NIGHT INTO SATURDAY, WHILE DRIER ON SUNDAY
WILL HAVE SPOTTY SHOWER ACTIVITY.
* TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL THIS WEEKEND.
* UNCERTAINTY WITH EARLY TO MIDDLE PART OF NEXT WEEK IN TERMS OF
TEMPERATURES, BUT DOES TREND DRIER.
THERE ARE NO WHOLESALE CHANGES TO THE MID-LEVEL PATTERN THROUGH THIS
WEEKEND, RIDGING IN THE WEST, TROUGHING IN THE EAST, AND CUT-OFF LOW
WELL TO THE NORTH IN EASTERN QUEBEC, CANADA. UNSETTLED CONDITIONS
BEST DESCRIBES WHAT TO EXPECT HEADING INTO THIS WEEKEND. OUR OF THE
TWO DAYS, SATURDAY WILL BE THE DAY WITH WIDESPREAD RAIN, OF WHICH
MAY BE HEAVY AT TIMES. SUNDAY WILL BE DRIER, THOUGH SPOTTY SHOWERS
REMAIN POSSIBLE. THE RIDGE IN THE WEST DOES SHIFT EAST TOWARDS THE
CENTRAL CONUS, THUS NUDGES THE TROUGH/CUT-OFF LOW FURTHER EAST. BUT,
THERE IS A GOOD SPREAD AMONGST THE DETERMINISTIC GUIDANCE ON HOW FAST
OR RATHER HOW SLOW IT TAKES FOR IT TO EXIT SOUTHERN NEW ENGLAND.
LEADING TO LOWER FORECASTER CONFIDENCE MONDAY THROUGH WEDNESDAY.
THIS WEEKEND IS ROUGHLY 50/50, WITH THE SOGGIEST WEATHER OCCURRING
LATE FRIDAY NIGHT AND SATURDAY. A LOW PRESSURE SYSTEM DEVELOPS SOUTH
OF THE REGION AND TRACKS NORTH/NORTHEAST. NOW, THERE IS A BIT OF
SPREAD IN THE GUIDANCE WHEN IT COMES TO THE POSITIONING OF THE LOW.
THE NAM 12KM/GFS FAVOR A TRACK ALONG AND TO THE WEST OF THE
CONNECTICUT RIVER, UKMET/ECMWF FAVOR A TRACK ALONG THE 95 CORRIDOR
BETWEEN PROVIDENCE AND BOSTON, WHILE THE GEM FAVORS A TRACK OVER
NANTUCKET. IF THIS WERE WINTER, WE'D BE STRESSED OVER A RAIN/SNOW
LINE. WHILE WE DON'T HAVE THAT ISSUE, THE FOCUS IS WHERE THE
GREATEST QPF FALLS, USUALLY NORTHWEST OF THE LOW. GIVEN THE GEM IS
AN OUTLIER, HAVE SOME CONFIDENCE THE GREATEST QPF WILL FALL ACROSS
WESTERN SOUTHERN NEW ENGLAND. THIS SYSTEM DOES NOT LOOK AS ROBUST AS
LAST WEEKS SYSTEM, ENSEMBLES HIGHLIGHT LOW TO MODERATE PROBABILITES,
20 TO 40 PERCENT, OF 2+ INCHES OF RAIN ACROSS CENTRAL AND WESTERN
MASSACHUSETTS AND CONNECTICUT. LIKELY AS THE WORSE CASE SCENARIO,
BUT FWIW, THE LAST SEVERAL RUNS OF THE NBM HAVE SHOWN A MEAN STORM
TOTAL, MORE LIKELY OUTCOME BETWEEN 0.5" AND 1.0", LESSER FOR CAPE
AND ISLANDS, WITH HIGHER AMOUNTS ACROSS THE INTERIOR. DRIER ON
SUNDAY AS THE LOW MOVES NORTH, WITH THE MID-LEVEL LOW OVER THE
REGION, STILL CANNOT RULE OUT SPOTTY SHOWER ACTIVITY. SEASONABLY
COOL, WITH BOTH DAYS RUNNING A FEW DEGREES BELOW THE NORMAL, HIGHS
ARE IN THE UPPER-60S TO LOW-70S, WITH NIGHTLY LOWS IN THE UPPER-40S
TO LOW-50S.
THE CUT-OFF LOW REMAINS OVERHEAD LIKELY THROUGH MONDAY, THEN WILL
BEGIN TO MOVE EAST TUESDAY/WEDNESDAY. BUT, THERE IS SPREAD IN THE
GUIDANCE IN HOW THIS UNFOLDS. UKMET/ECMWF SHOW THE RIDGING FROM THE
WEST BUILDING IN, BUT THE GFS/GEM SHOW THE CUT-OFF LOW MEANDERING
OFF SHORE. FIRST OUTCOME WOULD LEAD TO MUCH WARMER WEATHER, WHILE
THE LATTER HALF COOLER.
AVIATION /12Z THURSDAY THROUGH MONDAY/
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
12Z TAF UPDATE...MODERATE CONFIDENCE.
LOW END MVFR TO IFR CONDITIONS WILL PERSIST TODAY WITH
SCATTERED -SHRA THE BULK OF WHICH WILL BE IN THE MORNING TO
EARLY AFTERNOON FOR THE RI AND SOUTHERN MA TERMINALS. SOME
IMPROVEMENT POSSIBLE TONIGHT BUT MVFR CEILINGS SHOULD PERSIST. S
WINDS THIS EVENING BECOME LIGHT SE OVERNIGHT AND THEN
E/EVENTUALLY ENE ON THU.
FRIDAY IFR TO START, ESPECIALLY SOUTH, WITH IMPROVING CONDITIONS
THROUGH THE DAY FOR TERMINALS AWAY FROM THE SOUTH COAST. WINDS
SW 5-10 KTS.
BOS TAF...MODERATE CONFIDENCE IN TAF.
BDL TAF...MODERATE CONFIDENCE IN TAF.
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...
FRIDAY NIGHT: MVFR/IFR CONDITIONS POSSIBLE. SHRA LIKELY,
ISOLATED TSRA.
SATURDAY: MAINLY MVFR, WITH LOCAL IFR POSSIBLE. BREEZY. SHRA,
ISOLATED TSRA.
SATURDAY NIGHT: MAINLY VFR, WITH LOCAL IFR POSSIBLE. BREEZY.
CHANCE SHRA.
SUNDAY: VFR. BREEZY. SLIGHT CHANCE SHRA.
SUNDAY NIGHT THROUGH MONDAY: VFR.
MARINE
FORECASTER CONFIDENCE LEVELS:
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
OVERALL HIGH CONFIDENCE THROUGH THE WEEKEND.
SCA CONTINUES FOR SEAS ON SOUTH COASTAL WATERS AS WEAK LOW
PRESSURE BRINGS MARGINAL 5-6 FT SEAS, MAINLY ON OPEN WATERS,
STARTING TODAY AND LINGERING INTO TONIGHT.
WEAK LOW PASSING NEAR CAPE COD AND ISLANDS TODAY WILL BRING
SHOWERS TODAY BUT WINDS STAY BELOW 15KT. TONIGHT SEAS DIMINISH
BELOW SCA CRITERIA WITH LIGHT WINDS AND THIS CONTINUES ON
FRIDAY.
OUTLOOK /FRIDAY NIGHT THROUGH MONDAY/...
FRIDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT. RAIN SHOWERS LIKELY, ISOLATED THUNDERSTORMS.
SATURDAY: WINDS LESS THAN 25 KT. LOCAL ROUGH SEAS. RAIN SHOWERS
LIKELY, ISOLATED THUNDERSTORMS.
SATURDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF ROUGH SEAS.
CHANCE OF RAIN SHOWERS.
SUNDAY: WINDS LESS THAN 25 KT. AREAS OF ROUGH SEAS. SLIGHT
CHANCE OF RAIN SHOWERS.
SUNDAY NIGHT: WINDS LESS THAN 25 KT. LOCAL ROUGH SEAS.
MONDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 2 AM EDT
FRIDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 AM EDT
FRIDAY FOR ANZ254>256.
SYNOPSIS...BW/DOOLEY
NEAR TERM...BW
SHORT TERM...BW
LONG TERM...DOOLEY
AVIATION...BW/DOOLEY
MARINE...BW/DOOLEY
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