100
FXUS61 KBOX 081809
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
209 PM EDT FRI AUG 8 2025
SYNOPSIS
HIGH PRESSURE WILL BRING WARM DAYS AND COMFORTABLY COOL NIGHTS
THROUGH SATURDAY NIGHT. WARMING TREND BEGINS IN EARNEST SUNDAY AS STRONG MID-LEVEL RIDGING
BUILDS OVER THE REGION. EXTENDED PERIOD OF WARM WEATHER LIKELY
CONTINUES THROUGH AT LEAST THURSDAY. TEMPERATURES AWAY FROM THE
SOUTH COAST WILL INCREASE TO 90 PLUS. UNSETTLED WEATHER RETURNS
LATER IN THE WEAK AS THE RIDGE BEGINS TO BREAK DOWN.
NEAR TERM /THROUGH TONIGHT/
TONIGHT:
HIGH PRESSURE REMAINS ANCHORED OVERHEAD TONIGHT, BRINGING ANOTHER
GORGEOUS EVENING WITH COMFORTABLE HUMIDITY. DEWPOINTS ARE ONCE
AGAIN IN THE UPPER 40S TO LOW 50S ACROSS THE REGION THIS
AFTERNOON. GIVEN LOW TEMPERATURES LAST NIGHT FELL TO AFTERNOONS
DEWPOINTS, EXPECTING LOWS TO ONCE AGAIN FALL TO THE UPPER 40S TO
LOW 50S WITH CLEAR SKIES. SKIES MAY CLOUD OVER NEAR THE SOUTH
COAST TONIGHT, AS LIGHT SOUTHERLY FLOW AND SATURATED AIR WILL BE
CONDUCIVE FOR THE FORMATION OF LOW STRATUS AND FOG.
SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/
SATURDAY AND SATURDAY NIGHT.
ANOTHER RINSE AND REPEAT WEATHER DAY AS HIGH TEMPERATURES WARM IN
THE LOW TO MID 80S WITH COMFORTABLE HUMIDITY AS DEWPOINTS REMAIN
BELOW 60F. WINDS REMAIN LIGHT OUT OF THE SSE WITH LOCALIZED SEA
BREEZES ALONG THE COASTS. OVERNIGHT LOWS STAY SLIGHTLY WARMER
SATURDAY NIGHT, BUT STILL DROP INTO THE 50S AWAY FROM URBAN CENTERS
AND COASTS. LOW STRATUS AND FOG ARE POSSIBLE AGAIN, MAINLY NEAR THE
SOUTH COAST.
LONG TERM /SUNDAY THROUGH FRIDAY/
KEY MESSAGES:
* MULTI-DAY STREAK OF ABOVE AVERAGE TEMPERATURES STILL LIKELY
STARTING SUNDAY
* A FEW SHOWERS OR T-STORMS POSSIBLE MID-LATE WEEK, BUT DRY PATTERN
OVERALL
GUIDANCE REMAINS CONSISTENT IN SHOWING A BUILDING UPPER LEVEL RIDGE
AND SURFACE HIGH PRESSURE ACROSS THE EASTERN CONUS. MODERATE TO HIGH
CONFIDENCE IN AN EXTENDED PERIOD OF 90+ DEGREE TEMPERATURES STARTING
SUNDAY AND LASTING THROUGH THURS. CONFIDENCE IN HEAT-RELATED
HEADLINES IS SOMEWHAT LOWER WITH THIS UPDATE AS LOWER DEWPOINTS MAY
KEEP MOST LOCATIONS FROM SEEING HEAT INDEX VALUES ABOVE 95 DEGREES.
STILL, THE EXTENDED STRETCH OF ABOVE NORMAL TEMPERATURES WILL POSE A
RISK FOR THOSE WITHOUT ACCESS TO PROPER COOLING AND TO THOSE WORKING
OUTDOORS. CONFIDENCE IN THE UPPER AIR PATTERN DECREASES LATE IN THE
WEEK GIVEN SPREAD AMONG DETERMINISTIC GUIDANCE REGARDING WHETHER THE
RIDGE WILL BREAK DOWN. HIGH CONFIDENCE IN THE FORECAST THROUGH WED
THEN DECREASING CONFIDENCE.
NBM STILL SHOWING 60-85% PROBS OF 90+ NEXT WEEK AWAY FROM THE
IMMEDIATE COAST. THE WORST OF THE HEAT IS EXPECTED IN THE INTERIOR
AS DAILY SEA-BREEZES MAY TEMPER THE HEAT SOMEWHAT NEAR THE COAST,
ESPECIALLY THE SOUTH COAST. IT APPEARS HUMIDITY LEVELS WILL BE
MODERATE THROUGH AT LEAST TUE AND POSSIBLY WED WITH DEWPOINTS MOSTLY
IN THE LOW-MID 60S WHICH WOULD KEEP HEAT INDICES A BIT BELOW
DANGEROUS THRESHOLDS. THE LOWER DEWPOINTS WILL ALSO ALLOW OVERNIGHT
LOW TEMPS TO FALL INTO THE 60S THROUGH MID WEEK. THE PROBABILITY OF
DEWPOINTS APPROACHING 70 INCREASES WED AND ESPECIALLY THU AS HIGHER
PWATS DEVELOP.
DRY WEATHER EXPECTED THROUGH AT LEAST TUE WITH SUBSIDENCE AND
LIMITED INSTABILITY IN PLACE. WHILE MOISTURE AND INSTABILITY
INCREASES LATER WED-THU, SYNOPTIC FORCING REMAINS WEAK. RISK FOR
DIURNAL SHOWERS/T-STORMS WILL INCREASE SOMEWHAT WED AND ESPECIALLY
THU AS INSTABILITY INCREASES. GREATER CHANCE FOR MORE ORGANIZED
CONVECTION FRIDAY AS A COLD FRONT PUSHES INTO THE REGION.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
18Z TAF UPDATE:
TONIGHT...MODERATE CONFIDENCE.
VFR OUTSIDE THE SOUTH COAST WHERE HREF PROBS FOR AN IFR STRATUS
DECK FORMING ARE AROUND 50-70%. CONFIDENCE IS ONLY MODERATE IN
THIS FORMING, AND LOW CONFIDENCE IFR VS LIFR. OTHERWISE PATCHY
GROUND FOG IS POSSIBLE AGAIN IN LOW LYING AREAS.
SATURDAY...HIGH CONFIDENCE
VFR. LIGHT SOUTHERLY WINDS WITH LOCALIZED SEA BREEZE
CIRCULATIONS.
SATURDAY NIGHT...LOW CONFIDENCE
WILL NEED TO WATCH FOR IFR/LIFR STRATUS ALONG THE SOUTH COAST
AGAIN, BUT CONFIDENCE IS LOW AT THIS TIME. OTHERWISE VFR FOR THE
INTERIOR WITH PATCHY GROUND FOG.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
VFR. SEA BREEZE SHOULD KICK OUT AROUND 02Z AGAIN TONIGHT AND
COME BACK SATURDAY MORNING BETWEEN 13-14Z. WILL NEED TO WATCH
THE SE STRATUS THE NEXT COUPLE OF NIGHTS, BUT SHOULD STAY SOUTH
OF TERMINAL.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
VFR. LIGHT SOUTHERLY WINDS
OUTLOOK /SUNDAY THROUGH WEDNESDAY/...
SUNDAY THROUGH MONDAY NIGHT: VFR.
TUESDAY: VFR. BREEZY.
TUESDAY NIGHT: VFR.
WEDNESDAY: VFR. BREEZY. SLIGHT CHANCE SHRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MEDIUM - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
THROUGH SATURDAY NIGHT...HIGH CONFIDENCE.
TRANQUIL BOATING CONDITIONS EXPECTED TO CONTINUE THROUGH SAT
NIGHT WITH E- SE WINDS 15 KT OR LESS. SEAS 3 FT OR LESS ALL
WATERS.
OUTLOOK /SUNDAY THROUGH WEDNESDAY/...
WINDS LESS THAN 25 KT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
SYNOPSIS...KP/FT
NEAR TERM...KP
SHORT TERM...KP
LONG TERM...FT
AVIATION...KP
MARINE...KP/FT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page