374
FXUS61 KBOX 132322
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
722 PM EDT WED MAY 13 2026
WHAT HAS CHANGED
NO SIGNFICANT CHANGES.
KEY MESSAGES
- WIDESPREAD RAINFALL THU INTO FRI, COOLING DOWN FRIDAY BEFORE
THE WEEKEND'S WARM-UP.
- DRY WITH WELL ABOVE NORMAL TEMPERATURES SATURDAY THROUGH THE
MIDDLE OF NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...WIDESPREAD RAINFALL THU INTO FRI, COOLING DOWN
FRIDAY BEFORE THE WEEKEND'S WARM-UP.
SOUTHERN NEW ENGLAND IS SITUATED BETWEEN HIGH PRESSURE OVER THE
WESTERN ATLANTIC AND A 1004MB LOW PRESSURE CENTER OVER THE GREAT
LAKES. THE WARM FRONT EXTENDING FROM THAT LOW IS MAKING ITS WAY
NORTH THROUGH NEW ENGLAND THIS AFTERNOON AND LED TO LIGHT SHOWERS
OUT AHEAD EARLIER THIS AFTERNOON. THESE HAVE CLEARED AND WE EXPECT
THAT TO REMAIN THE CASE THE REST OF THE DAY AS SOME MARGINALLY DRIER
AIR MOVES IN IN THE 850-600MB LAYER AND A LACK OF MUCH FORCING
BEHIND THE FRONT. OTHERWISE, BREEZY CONDITIONS THE REST OF THE DAY
AS THE WELL MIXED BL TAPS INTO A 35-40 KT 850MB JET OVERHEAD.
AS THE UPPER LEVEL LOW DIGS INTO THE SOUTHEAST IT SETS US UP FOR A
COOL AND WET THURSDAY (LINGERING INTO FRIDAY THANKS TO THE
AMPLIFIED, SLOWLY EVOLVING PATTERN). THIS PLACES SNE BENEATH A PLUME
OF ANOMOLOUS MOISTURE (PWATS OVER 1" ARE IN THE 99TH PERCENTILE OF
CLIMATOLOGY). TOGETHER WITH STRONG SYNOPTIC FORCING FROM STRONG PVA,
FAVORABLE PLACEMENT BENEATH A 300MB JET, AND CONVERGENCE IN THE MID
LEVELS MOST LOCATIONS IN THE REGION CAN EXPECT 1 TO 2 INCHES OF RAIN
BEFORE ALL IS SAID AND DONE. RAIN ARRIVES IN WESTERN SNE THURSDAY
MORNING, OVERSPREADING THE REGION THROUGH THE DAY AND ENDING IN THE
EARLY OVERNIGHT HOURS. THERE MAY BE TWO BULLSEYES OF HIGHEST RAIN
TOTALS, ONE OVER THE WESTERN MA/CT HIGH TERRAIN THANKS TO UPSLOPE
FLOW, AND ANOTHER OVER EASTERN MA ASSOCIATED WITH A SECONDARY
LOW THAT LOOKS TO FORM BETWEEN THE PARENT LOW TO OUR NW AND
ANOTHER DISTURBANCE PASSING BY OVER THE ATLANTIC. FORTUNATELY,
GIVEN THE PROLONGED NATURE OF THE RAIN, NOT EXPECTING FLOODING
TO BE A CONCERN. FINALLY, DEWPOINTS MAY REACH THE LOW TO MID 50S
THURSDAY AFTERNOON CONTRIBUTING TO SEVERAL HUNDRED J/KG OF
ELEVATED CAPE, SO MAY HAVE SOME EMBEDDED THUNDERSTORMS AS WELL.
FRIDAY WILL BE DRIER AS THE SURFACE LOW SLOWLY MOVES EAST BUT THE
UPPER LOW LINGERS OVERHEAD. THIS TURNS WINDS OUT OF THE NORTHEAST
WHILE LOW LEVEL MOISTURE REMAINS LOCKED IN. SO, EXPECT A COOL,
CLOUDY, DAY WITH OFF AND ON LIGHT RAIN/DRIZZLE; MORE LIKELY TO
REMAIN DRY THE FURTHER WEST YOU GO. THE UPPER LEVEL AIRMASS DOESN'T
CHANGE MUCH, SO EXPECTING HIGH TEMPERATURES FOR THE WESTERN HALF OF
THE REGION TO BE SIMILAR TO THURSDAY, IN THE UPPER 50S (HIGH
ELEVATION) TO LOW 60S (CT VALLEY). THE DIFFERENCE WILL BE FELT IN
EASTERN MA AND RI WHERE THAT ONSHORE FLOW WILL DROP HIGH
TEMPERATURES FROM THE LOW/MID 60S THURSDAY TO THE UPPER 50S ON
FRIDAY. THIS IS APPROACHING 10 DEGREES COOLER THAN NORMAL.
KEY MESSAGE 2...DRY WITH WELL ABOVE NORMAL TEMPERATURES
SATURDAY THROUGH THE MIDDLE OF NEXT WEEK.
A PERSISTENT RIDGE SETS UP OVER THE EAST CONUS ON SATURDAY AND
REMAINS QUASI-STATIONARY THROUGH THE MIDDLE OF NEXT WEEK. THIS WILL
SUPPORT A PERSISTENT AREA OF HIGH PRESSURE OFF THE SOUTHEAST THAT
WILL ADVECT WARM, MOIST AIR INTO SOUTHERN NEW ENGLAND FOR
SEVERAL DAYS. EXPECT SEVERAL CONSECUTIVE DAYS WITH HIGH
TEMPERATURES IN THE 70S FOR MUCH OF SOUTHERN NEW ENGLAND, WITH
LOW TO MID 80S POSSIBLE ON TUESDAY AND WEDNESDAY. LOW TEMPS
FORECAST TO BE MAINLY IN THE 50S DURING THIS STRETCH. OVERALL A
WARM,DRY, AND QUIET STRETCH OF WEATHER BETWEEN SATURDAY AND THE
MIDDLE OF NEXT WEEK.
AVIATION /00Z THURSDAY THROUGH MONDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
00Z TAF UPDATE:
TONIGHT...HIGH CONFIDENCE.
VFR CIGS TO START THEN BECOMING MVFR/IFR AFTER 08Z FROM WEST TO
EAST. FEW SHOWERS ARE POSSIBLE IN WEST/CENTRAL SOUTHERN NEW
ENGLAND AFTER 06Z. AS SURFACE WINDS SLACKEN AFTER 00Z, MARGINAL
LLWS POSSIBLE GIVEN MODEST LOW LEVEL SW JET OF 35-40 KT.
THURSDAY...HIGH CONFIDENCE ON TRENDS BUT SOME UNCERTAINTY ON
EXACT TIMING OF DETAILS.
MVFR/IFR WITH PERIODS OF RAIN, MODERATE TO HEAVY AT TIMES. 20-25%
PROBABILITY OF -TSRA IN EMBEDDED HEAVIER SHOWERS. ESE WINDS AT
8-12 KTS WITH A OCCASIONAL GUST UP TO 20 KTS.
THURSDAY NIGHT...HIGH CONFIDENCE.
IFR/LIFR CIGS. WIDESPREAD MODERATE TO HEAVY RAIN ENDS BUT LIGHT
RAIN/DRIZZLE CONTINUES. WINDS LIGHT NE.
KBOS...HIGH CONFIDENCE.
KBDL...HIGH CONFIDENCE.
OUTLOOK /FRIDAY THROUGH MONDAY/...
FRIDAY: MAINLY VFR, WITH AREAS IFR POSSIBLE. SHRA LIKELY.
FRIDAY NIGHT: VFR.
SATURDAY THROUGH SUNDAY: VFR. BREEZY.
SUNDAY NIGHT THROUGH MONDAY: VFR.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
2 AM UPDATE...
TODAY THROUGH THURSDAY...HIGH CONFIDENCE.
STRENGTHENING LOW LEVEL SW JET MOVES ACROSS SNE TODAY, WITH LIGHT SW
EARLY THIS MORNING, BECOMING SOUTH AND INCREASING TO 20-25 KT THIS
AFTERNOON, EXCEPT 25-30 KT IN GUSTS NEAR SHORE. HENCE, SCA REMAINS
POSTED. OTHER THAN A SPOT MORNING SHOWER ACROSS NORTHERN MA WATERS,
DRY WEATHER AND GOOD VSBY PREVAIL TODAY. SOUTH WINDS SLACKEN TONIGHT
WITH MAINLY DRY WEATHER. ROUGH CONDITIONS THU, WITH S-SE WINDS 20-25
KT IN THE MORNING, THEN SLACKEN IN THE AFTERNOON AND BECOME EAST AS
LOW PRESSURE TRACKS SOUTH OF NEW ENGLAND. THIS LOW WILL BRING
WIDESPREAD RAIN TO REGION THU, MODERATE TO HEAVY AT TIMES WITH
REDUCED VSBY.
OUTLOOK /FRIDAY THROUGH MONDAY/...
FRIDAY: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT. CHANCE OF RAIN
SHOWERS.
FRIDAY NIGHT: WINDS LESS THAN 25 KT. SEAS UP TO 5 FT.
SATURDAY: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH GUSTS UP
TO 25 KT. SEAS UP TO 5 FT.
SATURDAY NIGHT: LOW RISK FOR SMALL CRAFT ADVISORY WINDS WITH
GUSTS UP TO 25 KT. AREAS OF SEAS APPROACHING 5 FT.
SUNDAY THROUGH 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 UNTIL 11 PM EDT THIS EVENING FOR
ANZ230>237-250-251-254>256.
DISCUSSION...BW/RM
AVIATION...BW/RM
MARINE...BW
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