032
FXUS61 KBOX 111920
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
320 PM EDT THU JUN 11 2026
WHAT HAS CHANGED
BOTH THE MARGINAL RISK (LEVEL 1 OF 5) AND SLIGHT RISK (LEVEL 2
OF 5) OF SEVERE WEATHER ON FRIDAY WERE PULLED BACK A BIT FURTHER
WEST; CHANCE OF SEVERE WEATHER IS LOW BUT NOT ZERO FOR EASTERN
MA/RI.
KEY MESSAGES
- HEAT AND HUMIDITY CONTINUES THROUGH FRIDAY BEFORE WE GET A BREAK
IN THE HUMIDITY, EVEN IF NOT SO MUCH FROM THE HEAT.
- AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE POSSIBLE
BOTH THURSDAY AND FRIDAY, A FEW OF WHICH COULD BE SEVERE.
- ABOVE NORMAL TEMPERATURES CONTINUE THIS WEEKEND BUT WITH A
LITTLE LESS HUMIDITY. DRY WEATHER PREVAILS UNTIL A RISK FOR
SHOWERS AND THUNDERSTORMS DEVELOPS SUNDAY NIGHT, AND A COUPLE
COULD BECOME STRONG.
- COOLDOWN TO MORE SEASONABLE TEMPERATURES WITH DRIER WEATHER
FOR EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...HEAT AND HUMIDITY CONTINUES THROUGH FRIDAY BEFORE WE
GET A BREAK IN THE HUMIDITY, EVEN IF NOT SO MUCH FROM THE HEAT.
TEMPERATURES IN THE 80S TO LOW 90S AND DEWPOINTS IN THE UPPER 60S TO
LOW 70S HAVE BROUGHT A MUGGY FEEL TO THE AIR TODAY UNDER A VERY
MOIST AIRMASS (PWATS NEAR 1.75"). 850 MB TEMPS SURGING TO NEAR 20C
TODAY WILL PERSIST THROUGH FRIDAY UNDER A BUILDING MID LEVEL RIDGE
AND THIS PROLONGS THE BOUT OF ABOVE NORMAL HEAT/HUMIDITY THROUGH
FRIDAY. THOSE ELEVATED DEWPOINTS WILL MAKE TEMPS IN THE UPPER 80S
AND 90S FEEL MORE LIKE THE 90S TO NEAR 100 (IN THE CT VALLEY). THE
EXCEPTION WILL BE ALONG THE COAST, ESPECIALLY THE EAST COAST OF MA
WHERE ONSHORE EASTERLY FLOW KEEPS TEMPS MORE COMFORTABLY IN THE 70S
TO MID 80S. THE HEAT ADVISORY CONTINUES THROUGH FRIDAY WITH LOW
TEMPERATURES LIMITED BY THE ELEVATED DEWPOINTS TO THE UPPER 60S/LOW
70S.
KEY MESSAGE 2...AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE
POSSIBLE BOTH THURSDAY AND FRIDAY, A FEW OF WHICH COULD BE SEVERE.
THE SAME HEAT AND HUMIDITY MENTIONED ABOVE ARE CONTRIBUTING TO
2,000+ J/KG OF CAPE ACROSS SNE THIS AFTERNOON AND THAT WILL BE
CONDUCIVE TO SCATTERED THUNDERSTORMS THIS AFTERNOON OWING TO A FEW
MID LEVEL SHORTWAVES PROVIDING ENOUGH LIFT AS THEY SLIDE OVERHEAD.
AMPLE MOISTURE AND INSTABILITY ARE AVAILABLE, BUT A LIMITING FACTOR
IS MINIMAL 0-6KM BULK SHEAR 20-25 KTS IN THE AREA WHERE THE BEST
FORCING AND INSTABILITY ARE. THAT BEING SAID, GIVEN THE MAGNITUDE OF
INSTABILITY IT SHOULD BE ENOUGH TO OVERCOME THE LIMITING SHEAR
VALUES TO PRODUCE A FEW STRONG STORMS, ONE OR TWO OF WHICH COULD BE
SEVERE. THE MAIN THREAT WILL BE DAMAGING WINDS WITH A BATCH OF
STORMS MOVING IN FROM NY; THIS IS WHERE THE GREATEST THREAT IS.
ANOTHER BATCH OF SHOWERS/STORMS LIKELY INITIALIZE ALONG A SEABREEZE
BOUNDARY OVER EASTERN MA THIS EVENING AS WELL WITH A LESSER SEVERE
RISK.
FRIDAY WE'LL HAVE A SIMILAR SETUP WITH NOT MUCH CHANGE IN THE
AIRMASS (INSTABILITY AND SHEAR SPECIFICALLY) AS THE BROADER MID
LEVEL SHORTWAVE APPROACHES SO MODEST HEIGHT FALLS AS WELL AS AN
APPROACHING COLD FRONT AND QUASI- SEABREEZE BOUNDARY WILL
PROVIDE SOME LIFT TO KICK OFF A FEW CLUSTERS OF THUNDERSTORMS.
THE FIRST TO SEE STORMS WILL LIKELY BE EASTERN MA AND RI WHERE
THAT QUASI- SEABREEZE BOUNDARY/ONSHORE FLOW WILL LIKELY HELP
INITIALIZE SOME STORMS BY MID AFTERNOON. AN APPROACHING COLD
FRONT FROM NY WILL ALSO BE MOVING THROUGH MIDNIGHT WHICH WILL
LEAD TO A BROKEN LINE OF STORMS FROM WEST TO EAST 7PM-MIDNIGHT;
HOWEVER, WE WILL BE LOSING OUR DIURNAL HEATING EARLY IN THAT
PERIOD SO INSTABILITY AND SEVERE POTENTIAL WILL BE DECREASING
QUICKLY; BEST CHANCE OF SEVERE WEATHER IS IN WESTERN MA AND CT
WHERE WE HAVE PLACED A SLIGHT (LEVEL 2 OF 5) SEVERE RISK.
KEY MESSAGE 3...ABOVE NORMAL TEMPERATURES CONTINUE THIS WEEKEND BUT
WITH A LITTLE LESS HUMIDITY. DRY WEATHER PREVAILS UNTIL A RISK FOR
SHOWERS AND THUNDERSTORMS DEVELOPS SUNDAY NIGHT, AND A COUPLE COULD
BECOME STRONG.
WHILE STILL VERY WARM TO HOT ON SATURDAY, WE SHOULD SEE A BIT LESS
HUMIDITY COMPARED TO THE PAST COUPLE DAYS. DRY WEATHER SHOULD
PREVAIL AS SHORTWAVE RIDGING GOVERNS, WITH AREAS ALONG THE MA EAST
COAST AND AROUND NARRAGANSETT BAY. HIGHS SHOULD AGAIN REACH WELL
INTO THE 80S TO LOW 90S BUT WITH DEWPOINT TEMPERATURES IN THE UPPER
50S/NEAR 60 COMPARED TO THE UPPER 60S/LOW 70S, IT SHOULD BE A
SOMEWHAT DRIER HEAT. UNDER SHORTWAVE RIDGING, THE RISK FOR AFTERNOON
STORMS ALSO LOOKS TO BE MITIGATED WITH DRY WEATHER ANTICIPATED.
SOUTHWEST FLOW RESUMES ON SUNDAY AND WITH IT COMES A BIT OF AN
INCREASE TO HUMIDITY LEVEL BUT NOT TO THE EXTENT OF TODAY OR FRIDAY.
WE'LL ALSO BE WAITING ON AN APPROACHING COLD FRONT TO TRIGGER
SHOWERS AND THUNDERSTORMS, AND WHILE THE EXACT TIMING VARIES,
THERE'S SOME GENERAL AGREEMENT ON IT BEING A LATER ARRIVAL (AFTER 5
PM) INTO WESTERN NEW ENGLAND. MIDLEVEL FLOW INCREASES SUNDAY IN
RESPONSE TO THE APPROACHING SHORTWAVE ALOFT WITH WSWLY 0-6 KM
SHEAR VECTOR MAGNITUDES AROUND 35 TO 45 KT, SUPPORTIVE OF SEVERE
WEATHER POTENTIAL. THE ISSUE IS MORE TEMPERED INSTABILITY WITH
THE LATER-DAY TIMING AND DEWPOINTS BEING ON THE LOWER SIDE, WITH
BETTER INSTABILITY MORE RESTRICTED TO THE NORTHERN MID-ATLANTIC
REGION WHERE SPC HAS DELINEATED A 15% PROBABILITY FOR SEVERE
STORMS. POPS INCREASE INTO THE LIKELY RANGE FOR SHOWERS AND
THUNDERSTORMS SUNDAY EVENING, BUT IF STORMS CAN PRODUCE SEVERE
WEATHER IS STILL A QUESTION MARK, WHICH WILL HINGE ON EITHER AN
EARLIER TIMING OR HIGHER FORECAST DEWPOINT TEMPERATURES.
KEY MESSAGE 4...COOLDOWN TO MORE SEASONABLE TEMPERATURES WITH DRIER
WEATHER FOR EARLY NEXT WEEK.
COOLDOWN TO TEMPERATURES FOR EARLY NEXT WEEK, AS THE OFFSHORE
PASSAGE OF THE COLD FRONT ALLOWS MORE OF SOUTHERN NEW ENGLAND TO
BECOME GOVERNED BY COOLER CYLONIC FLOW ALOFT. 850 MB TEMPS DROP TO
AROUND THE +10 TO +12C RANGE VERSUS THE +16 TO +18C RANGE,
SUPPORTING HIGHS IN THE 70S TO LOW 80S UNDER SUNNY CONDITIONS TO GO
ALONG WITH COMFORTABLE HUMIDITIES. DRY WEATHER ALSO PREVAILS THROUGH
TUESDAY UNTIL A WAVE OF LOW PRESSURE IN SW FLOW BRINGS A RISK FOR
SHOWERS AND THUNDERSTORMS AROUND MIDWEEK.
AVIATION /19Z THURSDAY THROUGH TUESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THIS AFTERNOON...MODERATE CONFIDENCE.
VFR EXCEPT FOR ACK WHERE IFR CIGS/VSBS PERSIST. THERE IS A RISK
FOR THUNDERSTORMS BETWEEN 19Z AND 02Z, BUT THE RISK IS HIGHEST
AT BDL. THERE IS A CHANCE FOR -SHRA/-TSRA AT THE OTHER
TERMINALS, BUT CONFIDENCE IS LOWER.
TONIGHT...MODERATE CONFIDENCE.
- SHRA/-TSRA TAPERS OFF BY 03-04Z. MAINLY VFR, WITH SOME MVFR/IFR
VSBYS DEVELOPING IN PATCHY FOG MAINLY OVER CAPE/ISLANDS. LIGHT
AND VARIABLE WINDS.
FRIDAY...MODERATE CONFIDENCE.
VFR. LIGHT ONSHORE WINDS DEVELOPING. A FEW ROUNDS OF TSRA
DEVELOPING, FIRST IN THE 18-00Z TIME PERIOD OVER EASTERN MA AND
RI TERMINALS, THEN AGAIN A BROKEN LINE OF STORMS IS POSSIBLE IN
THE 23Z-06Z PERIOD.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. RISK FOR -TSRA THIS
AFTERNOON/EVENING BETWEEN 23Z AND 02Z BUT MAY DEPEND ON IF THE
SEABREEZE MAKES IT INTO THE TERMINAL WHICH IS BECOMING MORE
UNCERTAIN THE LATER INTO THE DAY WE GET.
FRIDAY NIGHT...HIGH CONFIDENCE IN TAF.
SHRA/TSRA EXITING BY 06Z. VFR. NW WINDS 5-10 KTS.
OUTLOOK /FRIDAY NIGHT THROUGH TUESDAY/...
SATURDAY: VFR. BREEZY.
SATURDAY NIGHT: VFR.
SUNDAY: VFR. BREEZY.
SUNDAY NIGHT: VFR. BREEZY. CHANCE SHRA, SLIGHT CHANCE TSRA.
MONDAY: VFR. CHANCE SHRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH FRIDAY NIGHT...HIGH CONFIDENCE.
SEAS 2-4 FEET FOR THE MAJORITY OF THE WATERS EXCEPT 3-5 FEET
ACROSS THE SOUTHERN OUTER WATERS TONIGHT. SW WINDS INCREASE TO
15-25 KT WITH GUSTS AS HIGH AS 30 KTS. SCA CONDITIONS CONTINUE
FOR THE SOUTHERN WATERS TODAY BEFORE GRADUALLY SUBSIDING BY THE
LATE EVENING. SEAS DECREASE TO 1-3 FT BY FRIDAY AND CONTINUE
INTO FRIDAY NIGHT. ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE THURSDAY NIGHT INTO FRIDAY MORNING
THEN AGAIN FRIDAY EVENING INTO FRIDAY NIGHT.
OUTLOOK /FRIDAY NIGHT THROUGH TUESDAY/...
FRIDAY NIGHT: WINDS LESS THAN 25 KT. CHANCE OF RAIN SHOWERS.
SATURDAY THROUGH SUNDAY: WINDS LESS THAN 25 KT.
SUNDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT. RAIN SHOWERS LIKELY, SLIGHT CHANCE OF THUNDERSTORMS.
MONDAY: WINDS LESS THAN 25 KT. CHANCE OF RAIN SHOWERS, SLIGHT
CHANCE OF THUNDERSTORMS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR CTZ002>004.
MA...HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR MAZ002>006-008>014-017-
018-026.
AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR MAZ013-
016>024.
RI...HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR RIZ001>004.
AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR RIZ001>008.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ254>256.
DISCUSSION...LOCONTO/BW
AVIATION...LOCONTO/BW
MARINE...LOCONTO/BW
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