666
FXUS61 KBOX 021850
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
250 PM EDT THU JUL 2 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES TO THE FORECAST.
KEY MESSAGES
- DANGEROUS PROLONGED HEATWAVE CONTINUES THROUGH SAT JULY 4TH.
AFTERNOON HEAT INDICES OF 100 TO 110 DEGREES AGAIN FRIDAY BUT
STILL 95 TO 100+ ON SATURDAY. LITTLE RELIEF AT NIGHT EITHER.
- LOW CONVECTIVE/SEVERE WEATHER PROBABILITY THROUGH TONIGHT
GIVEN THE LACK OF FORCING. HOWEVER, IF ISOLATED STORMS ARE
ABLE TO DEVELOP, THEY COULD BECOME SEVERE. THE THUNDERSTORM
AND SEVERE WEATHER POTENTIAL INCREASES LATE FRIDAY AND/OR
SATURDAY AHEAD OF AN APPROACHING COLD FRONT.
- RELIEF FROM THE HEAT WITH COOLER AND MORE SEASONABLE
TEMPERATURES RETURNING FOR THE FIRST HALF OF NEXT WEEK.
DISCUSSION
KEY MESSAGE 1... DANGEROUS PROLONGED HEATWAVE CONTINUES THROUGH
SAT JULY 4TH. AFTERNOON HEAT INDICES OF 100 TO 110 DEGREES
AGAIN FRIDAY BUT STILL 95 TO 100+ ON SATURDAY. LITTLE RELIEF AT
NIGHT EITHER.
DANGEROUS HEATWAVE ONGOING ACROSS NEW ENGLAND TODAY AND FRIDAY. AS
OF 2 PM EDT, BOSTON (KBOS) HAS ALREADY BROKEN THE HIGH TEMPERATURE
RECORD TODAY, WITH 99F RECORDED A HANDFUL OF TIMES SO FAR THIS
AFTERNOON (PREVIOUS RECORD WAS 98F IN 1963). RECORDING 100F HERE HAS
YET TO OCCUR, BUT IS CERTAINLY WITHIN REACH OVER THE NEXT COUPLE OF
HOURS. TIME WILL TELL.
925MB TEMPS HAVE BEEN HANGING AT 28-29C TODAY, AND WILL CONTINUE
THROUGH FRIDAY. CENTER OF THE RIDGE IN THE CAROLINA PIEDMONT SINKS
EVER SO SLIGHTLY FRIDAY, ALLOWING HEIGHTS TO FALL A TAD. AS A
RESULT, HIGH TEMPERATURES ARE JUST A TOUCH "COOLER" FRIDAY (NOT THAT
YOU'LL REALLY FEEL A DIFFERENCE). DEWPOINTS ARE STILL WELL INTO THE
70S THE WHOLE TIME, MEANING THAT THE HEAT/HUMIDITY COMBINATION WON'T
HAVE A PROBLEM YIELDING HEAT INDICES WELL INTO THE TRIPLE DIGITS
(100-110F) ACROSS MOST OF NEW ENGLAND.
STILL HOT BUT A BIT MORE UNCERTAINTY INTRODUCED TO SATURDAY
BASED ON FRONTAL TIMING. THE SPREAD IN 850 MB TEMPS ACROSS
GUIDANCE HAS INCREASED TO ANYWHERE BETWEEN +15C AND +19 OR +20C.
WITH WESTERLY DOWNSLOPING WINDS AND COMPRESSIONAL WARMING AHEAD
OF THE FRONT ADDING A COUPLE OF DEGREES THAT COULD MEAN
ANYWHERE FROM NEAR 90 TO MID 90S. NBM GUIDANCE IS PROBABLY A
LITTLE OVERBAKED BUT NOT BY A MEANINGFUL DEGREE. IT WILL STILL
BE HOT AND DEWPOINTS WILL STILL MAKE IT FEEL A GOOD 5 TO 10
DEGREES WARMER THAN THE AIR TEMPS. SO EVEN IF MANY SITES DO NOT
HIT EXACT EXTREME HEAT CRITERIA, THE PROLONGED NATURE OF THE
HEAT PLUS THE HOLIDAY OUTDOOR ACTIVITIES MEAN THAT THE EXTREME
HEAT WARNING AND HEAT ADVISORY FOR MOST OF THE CAPE AND ISLANDS
SHOULD CONTINUE THRU SAT.
KEY MESSAGE 2... LOW CONVECTIVE/SEVERE WEATHER PROBABILITY
THROUGH TONIGHT GIVEN THE LACK OF FORCING. HOWEVER IF ISOLATED
STORMS ARE ABLE TO DEVELOP THEY COULD BECOME SEVERE. THE
THUNDERSTORM AND SEVERE WEATHER POTENTIAL INCREASES LATE FRIDAY
AND/OR SATURDAY AHEAD OF AN APPROACHING COLD FRONT.
COLD FRONT IS FORECAST TO BE IN THE VICINITY OF SOUTHERN NEW
ENGLAND SAT. IT WILL STILL BE HOT/HUMID AND THERE WILL BE MORE
THAN ENOUGH SHEAR TO ORGANIZE CONVECTION. THE LIMITING FACTOR
NOW APPEARS TO BE LAPSE RATES, GENERALLY AROUND 6C/KM. SO
GUIDANCE IS STRUGGLING TO PUSH CAPE NORTH OF 1000 J/KG. IT IS A
LITTLE LONG RANGE FOR SOME OF THE CAM GUIDANCE, BUT THERE IS
EVERYTHING FROM LITTLE TO NO CONVECTION TO FAIRLY WIDESPREAD
STORMS FROM THE RRFS. I HAVE A HARD TIME SEEING THE HEAT
BREAKING WITHOUT SOME SHOWERS AND STORMS TO CLEAR IT OUT, SO
MUCH OF WHAT HAPPENS SAT MAY DEPEND ON FRI/FRI NIGHT. ONCE AGAIN
PRIMARY SEVERE THREAT WOULD COME FROM DAMAGING WINDS AND
PERHAPS SOME LARGE HAIL.
KEY MESSAGE 3...RELIEF FROM THE HEAT WITH COOLER AND MORE
SEASONABLE TEMPERATURES RETURNING FOR THE FIRST HALF OF NEXT
WEEK.
LONG RANGE ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT IN THE UPPER
LEVEL RIDGE BREAKING DOWN AND A TENDENCY TOWARDS LOWER HEIGHTS
NEXT WEEK. THIS WILL BRING AN END TO THE EXTREME HEAT, WITH
READINGS MORE IN LINE WITH TYPICAL SUMMER. GUIDANCE IS ALSO
INCREASING POP TOWARDS TUE AS A WEAK UPPER LOW DRIFTS OR OPENS
UP AS IT CROSSES THE REGION. PRECIP CHANCES REMAIN LOW
CONFIDENCE HOWEVER, WITH LARGE SPREAD BETWEEN THE 25TH AND 75TH
PERCENTILE QPF.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE...
TODAY THROUGH FRIDAY...HIGH CONFIDENCE.
MAINLY VFR CONDITIONS INTO FRIDAY EVENING. FEW TO SCT CUMULUS AT
7000-8000 FT HAS DEVELOPED, BUT THE DECKS HAVE REMAINED SHALLOW.
CAPPING HAS KEPT CONVECTION FROM INITIATING, AND THAT SHOULD
CONTINUE THROUGH MUCH OF THIS AFTERNOON AND EVENING. FOG/STRATUS
DEVELOPMENT AGAIN LIKELY LATE THIS EVENING AND OVERNIGHT FOR
TERMINALS ACROSS THE CAPE AND ISLANDS. GREATER RISK FOR SOME
THUNDERSTORMS IN STORE FOR SATURDAY.
WESTERLY WINDS MAY GUST TO 20-25 KNOTS THIS AFTERNOON WITH SOME
SW WIND GUSTS AROUND 25 KNOTS TOWARDS THE CAPE AND ISLANDS.
ANOTHER ROUND OF WESTERLY 20+ KNOT GUSTS WILL DEVELOP AGAIN
DURING THE DAY FRIDAY.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. THINKING GRADIENT REMAINS
STRONG ENOUGH TODAY TO PREVENT A SEA BREEZE.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /FRIDAY NIGHT THROUGH TUESDAY/...
INDEPENDENCE DAY: VFR. BREEZY. CHANCE SHRA, SLIGHT CHANCE TSRA.
SATURDAY NIGHT THROUGH SUNDAY: VFR.
SUNDAY NIGHT: VFR. SLIGHT CHANCE SHRA.
MONDAY THROUGH MONDAY NIGHT: VFR. CHANCE SHRA.
TUESDAY: VFR. BREEZY. CHANCE SHRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
TODAY THROUGH FRIDAY...HIGH CONFIDENCE.
SW WINDS WILL GUST TO 25 KNOTS AT TIMES TODAY AND LONG FETCH WILL
RESULT IN 3 TO 5 FOOT ACROSS OUR SOUTHERN WATERS. THEREFORE...WE
HAVE CONTINUED SMALL CRAFT HEADLINES FOR OUR SOUTHERN WATERS
UNTIL 6 PM EDT THIS EVENING. WINDS SHOULD DIMINISH A TAD AND
TURN TO MORE OF A WESTERLY COMPONENT TONIGHT INTO
FRIDAY...ALLOWING US TO DROP THE SMALL CRAFT HEADLINES BY THAT
TIME.
OUTLOOK /FRIDAY NIGHT THROUGH TUESDAY/...
INDEPENDENCE DAY: WINDS LESS THAN 25 KT. CHANCE OF RAIN
SHOWERS, SLIGHT CHANCE OF THUNDERSTORMS.
SATURDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT. CHANCE OF RAIN SHOWERS.
SUNDAY: WINDS LESS THAN 25 KT.
SUNDAY NIGHT: WINDS LESS THAN 25 KT. SLIGHT CHANCE OF RAIN
SHOWERS.
MONDAY THROUGH MONDAY NIGHT: WINDS LESS THAN 25 KT. CHANCE OF
RAIN SHOWERS.
TUESDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING 5 FT.
CHANCE OF RAIN SHOWERS.
CLIMATE
RECORD HIGH TEMPERATURES:
JULY 2:
KBOS: 98/1963
KBDL: 99/1966
KPVD: 98/1941
KORH: 97/1901
JULY 3:
KBOS: 102/1911
KBDL: 102/1966
KPVD: 98/2002
KORH: 96/1911
JULY 4:
KBOS: 104/1911
KBDL: 99/1911
KPVD: 99/1919
KORH: 102/1911
RECORD HIGH MINIMUM TEMPERATURES:
JULY 2:
KBOS: 76/2002
KBDL: 73/2018
KPVD: 75/1941
KORH: 73/1963
JULY 3:
KBOS: 80/2002
KBDL: 73/2018
KPVD: 78/2002
KORH: 72/2002
JULY 4:
KBOS: 77/2002
KBDL: 74/2018
KPVD: 77/2002
KORH: 73/2018
JULY 5:
KBOS: 81/1999
KBDL: 77/1999
KPVD: 78/1999
KORH: 73/1999
BOX WATCHES/WARNINGS/ADVISORIES
CT...EXTREME HEAT WARNING UNTIL 8 PM EDT SATURDAY FOR CTZ002>004.
MA...EXTREME HEAT WARNING UNTIL 8 PM EDT SATURDAY FOR MAZ002>021-
026.
AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR MAZ006-007-
013>024.
HEAT ADVISORY UNTIL 8 PM EDT SATURDAY FOR MAZ022-023.
RI...EXTREME HEAT WARNING UNTIL 8 PM EDT SATURDAY FOR RIZ001>007.
AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR RIZ001>008.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
ANZ231>235-237.
SMALL CRAFT ADVISORY UNTIL 1 AM EDT FRIDAY FOR ANZ254>256.
DISCUSSION...BOATMAN/LEGRO
AVIATION...BOATMAN
MARINE...BOATMAN
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