Woburn Weather Center  63.6°F

Area Forecast Discussion
National Weather Service Boston/Norton MA
237 AM EDT Mon Jul 21 2025

SYNOPSIS
It will turn cooler and much less humid Monday and Tuesday.
A warming trend begins Wednesday, with heat and humidity
returning for Thursday and especially Friday when highs may
reach 95 to 100 degrees resulting in dangerous Heat Indices.
Summer heat and humidity may persist into next weekend...although
probably not to the magnitude of what we are expecting for
Friday. Dry weather for much of the work week, but the risk for
a few showers and thunderstorms begins Friday and continues into
next weekend.

.NEAR TERM /THROUGH TODAY/...
230 AM Update:

Key Message:

* Sunny, a little breezy and much less humid. Highs 70s to low 80s.

Details:

Surface cold front has passed into the southeast offshore waters,
with northerly winds in place and dewpoints beginning to fall into
the 60s. The real airmass change is still working its way south
through central VT/central NH, where dewpoint temps are commonly in
the mid 50s.

Really nice day shaping up for Southern New England as ridging
associated with a 1020 mb sfc Canadian-origin anticyclone builds
into the region. This will supply a few fair weather cloudiness but
full sun and much lower humidity levels as dewpoints plummett into
the 50s and even some upper 40s toward later in the day. Until then,
combo of rather deep mixing to 800 mb and 3-hourly pressure rises
around 3-4 mb will support northerly breezes, with speeds 10-15 mph
and developing gusts up to 25 mph picking up around mid to late
morning. Overall a mostly sunny, breezy and much less humid day
ideal for outdoor plans, with highs in the 70s to near 80.


.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
230 AM Update:

Key Messages:

* Clear skies/light winds tonight and again on Tue night,
  cooler lows upper 40s - mid 50s.

* Sunny Tue, cooler seabreezes near coasts, highs mid 70s-low 80s.

Details:

1020 mb high pressure continues to build southward into New England
tonight. Clear skies and a decoupling boundary layer after sundown
tonight should favor strong radiational cooling, with 925 mb temps
dropping to a seasonably-cool +11-13C. Tonight is without question
one of those nights where you can give your A/C or central air units
a break and open those windows. MOS guidance should do pretty well
tonight, with lows in the upper 40s to the mid 50s (urban and
coastal areas). Coolest lows in the locations which typically
radiate well.

Cooler start for a typical late-July day on Tuesday, although temps
should recover pretty well under full sun with comfortable
humidities. Still should see highs recover back into the 70s to low
80s, though a seabreeze on both eastern and southern coasts
occurring pretty early in the day should keep highs in the mid 70s.

For Tuesday evening...still another strong radiational cooling night
as high pressure slides offshore. But as it does so, dewpoints start
to rise into the lower to mid 50s. Could lead to patchy fog as
cooling temps thru radiational effects are met with rising dewpoints
but confidence is low on development. Lows in the 50s, still a
pretty nice evening overall.

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Key Messages:

* Turning warmer and increasingly more humid Wed thru Fri.

* Elevated heat indices Thu (mid 90s), with dangerous heat indices
  (100-105+) by Fri. Heat headlines possible.

* Dry weather thru Thurs, but a cold front Fri supports a potential
  for thunderstorms, although it is unclear on how strong any storms
  may become.

* Humid weekend with stalled frontal boundary around, which could
  favor opportunies for showers/storms but temps could be a touch
  cooler than on Fri.

Details:

Wednesday through Friday:

High pressure which settled over the southern waters will continue
to shift southward on Wed, which will herald the start of a warming
trend to temperatures and also allow for increasingly-rising levels
of humidity. Increasing heat and humidity are expected by Thurs with
heat indices in the mid to upper 90s; the peak of the heat and
humidity still looks to be on Fri, with the potential for dangerous
heat indices around 100-105 degrees or perhaps greater, as 850 mb
temps rise into the low-20s C. SWly flow looks strong enough through
this period to mitigate seabreezes, thus very warm temps are
expected to reach into coastal areas. Heat headlines will probably
be needed at some point for the late-week period; heat indices are
borderline Thu but are more solid for Fri.

Wed and Thurs look to feature dry weather despite building warm
temps and rising dewpoints, with subsidence and lack of sufficient
forcing mechanisms offsetting a moderate degree of instability. By
Friday, a weak cool front will be working its way southward, which
will also coincide with the peak of the heat and humidity. Will have
to see if this front lines up with peak heating to favor potential
for stronger storms; currently machine-learning severe weather progs
from Colorado State show low (5%) probs for severe weather for Fri.

The Weekend:

The cold front from Friday then looks to stall and weaken over or
just south of Southern New England, in a regime of weak troughing
per ensemble means. This is a pattern which would keep our weather
pattern unsettled with periods of showers and storms around in and
near the remnant frontal boundary, although the placement of it will
be key in determining where showers/storms would be more favored.
For now kept PoPs pretty generic at a 15-25% range but these will
need to be better refined as we move through the workweek.

It is possible that heat and humidity could lead to elevated heat
indices this weekend, but location of the front and potential for
considerable cloudiness casts more uncertainty on those values.
Highs in the mid to upper 80s with heat indices in the lower to mid
90s are currently forecast, but these could need adjusting either up
or down once confidence grows in the exact placement of the
remnant frontal boundary.

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

06z TAF Update:

Through 12z Tuesday: High confidence.

VFR. NW winds pick up to around 10-15 kt, with gusts 20-25 kt
starting 13-15z thru sundown. Winds then slacken to 5-10 kt
tonight, higher eastern terminals.

Tuesday: High confidence.

VFR continues with light north winds; seabreezes on both coasts
which could develop on the earlier end of seabreeze climo, around
14z.

Tuesday Night: High confidence.

VFR, with light S winds. Radiation fog for southern/southwest
airports is possible.

KBOS terminal...High confidence in TAF

KBDL terminal...High confidence in TAF

Outlook /Wednesday through Friday/...

Wednesday through Thursday Night: VFR. Breezy.

Friday: VFR. Breezy. Slight chance SHRA, slight chance TSRA.

.MARINE...
Forecaster Confidence Levels...

Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.

Through Tuesday Night: High confidence.

N/NW winds could gust to near-SCA levels (around 20 kt) around
early to mid Monday morning until midafternoon, though I didn`t
think gusts of 25+ kts would be persistent enough for SCA
headlines. NW winds then subside to light levels tonight, which
remain light northerly on Tue (nearshore seabreezes). Winds then
become S/SW around 5-10 kt Tue night. Seas mainly 3 ft or less
through the period, except nearing 4 ft early this morning. No
obstructions to visibility expected thru Tue night.

Outlook /Wednesday through Friday/...

Wednesday through Wednesday Night: Winds less than 25 kt.

Thursday: Low risk for Small Craft Advisory winds with local
gusts up to 30 kt. Seas locally approaching 5 ft.

Thursday Night: Moderate risk for Small Craft Advisory winds
with areas of gusts up to 30 kt. Seas up to 5 ft.

Friday: Moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Areas of seas approaching 5 ft. Slight chance of
rain showers.

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

SYNOPSIS...Loconto
NEAR TERM...Loconto
SHORT TERM...Loconto
LONG TERM...Loconto
AVIATION...Loconto
MARINE...Loconto          

Zone Forecast Product for Southern New England
National Weather Service Boston/Norton MA
104 AM EDT Mon Jul 21 2025

Forecast Synopsis
It will turn cooler and much less humid Monday and Tuesday.
A warming trend begins Wednesday, with heat and humidity
returning for Thursday and especially Friday when highs may
reach 95 to 100 degrees resulting in dangerous Heat Indices.
Summer heat and humidity may persist into next weekend...although
probably not to the magnitude of what we are expecting for
Friday. Dry weather for much of the work week, but the risk for
a few showers and thunderstorms begins Friday and continues into
next weekend.

Southeast Middlesex MA-
Including the city of Cambridge
104 AM EDT Mon Jul 21 2025

.REST OF TONIGHT...Mostly clear. Lows in the mid 60s. Northwest
winds 5 to 10 mph with gusts up to 20 mph.
.MONDAY...Mostly sunny. Cooler with highs in the upper 70s.
Northwest winds 10 to 15 mph.
.MONDAY NIGHT...Mostly clear. Cooler with lows in the mid 50s.
Northwest winds 5 to 10 mph.
.TUESDAY...Sunny. Highs in the upper 70s. Northwest winds around
5 mph, becoming northeast in the afternoon.
.TUESDAY NIGHT...Mostly clear. Lows in the mid 50s. Southeast
winds around 5 mph, becoming southwest around 5 mph after
midnight.
.WEDNESDAY...Sunny. Highs in the mid 80s.
.WEDNESDAY NIGHT AND THURSDAY...Partly cloudy. Hot. Lows in the
upper 60s. Highs in the lower 90s.
.THURSDAY NIGHT...Partly cloudy. Lows in the mid 70s.
.FRIDAY...Partly sunny with a chance of showers and
thunderstorms. Hot with highs in the upper 90s. Chance of rain
40 percent. Heat index values up to 105.
.FRIDAY NIGHT...Mostly cloudy with a chance of showers and
thunderstorms. Lows in the mid 70s. Chance of rain 40 percent.
Heat index values up to 100 early in the evening.
.SATURDAY...Partly sunny with a chance of showers and
thunderstorms. Not as warm with highs in the upper 80s. Chance of
rain 30 percent.
.SATURDAY NIGHT AND SUNDAY...Partly cloudy. A chance of showers
and thunderstorms. Lows in the upper 60s. Highs in the lower 80s.
Chance of rain 30 percent.          

REGIONAL WEATHER ROUNDUP
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
300 AM EDT MON JUL 21 2025

NOTE:  "FAIR" INDICATES FEW OR NO CLOUDS BELOW 12,000 FEET WITH NO
SIGNIFICANT WEATHER AND/OR OBSTRUCTIONS TO VISIBILITY.

MAZALL-210800-
EASTERN MASSACHUSETTS

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
BOSTON         CLEAR     68  62  81 NW10      29.75S
BEVERLY        CLEAR     65  63  93 NW7       29.74S
LAWRENCE       CLEAR     65  62  90 CALM      29.77S
BEDFORD        CLEAR     64  62  93 NW7       29.74F
NORWOOD        CLEAR     65  63  93 CALM      29.76S
MARSHFIELD     CLEAR    N/A N/A N/A MISG      29.73S
PLYMOUTH       CLEAR     67  66  97 NW9       29.73S
TAUNTON        CLEAR     65  63  93 CALM      29.75R
NEW BEDFORD    CLEAR     66  64  93 VRB3      29.73S


MAZALL-210800-
CAPE COD AND THE ISLANDS

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
FALMOUTH       MOCLDY    72  68  88 N7        29.74S
HYANNIS        CLOUDY    67  65  93 N9        29.71S
CHATHAM        CLOUDY    69  65  86 N9G18     29.72S
PROVINCETOWN   CLEAR     67  67 100 NW9       29.73S
NANTUCKET      MOCLDY    69  67  93 N18G30    29.71R
MARTHAS VNYRD  CLEAR     68  66  93 N7        29.72R


MAZALL-210800-
CENTRAL AND WESTERN MASSACHUSETTS

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
WORCESTER      CLEAR     64  59  83 NW9       29.80
FITCHBURG      CLEAR     64  60  87 NW7       29.79S
ORANGE         CLEAR     60  58  92 CALM      29.81S
SPRINGFIELD    CLEAR     62  60  95 CALM      29.76F
WESTFIELD      CLEAR     63  62  97 NE3       29.79F
NORTH ADAMS    CLOUDY    61  60  97 W5        29.84S
PITTSFIELD     CLEAR     63  60  90 NW3       29.84S


RIZALL-210800-
RHODE ISLAND

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
PROVIDENCE     CLEAR     69  63  81 NW9       29.76S
NEWPORT        CLEAR     68  64  87 N9        29.75R
BLOCK ISLAND   CLEAR     68  66  93 NW8       29.76R
SMITHFIELD     CLEAR     64  32  30 NW6       29.77F
WESTERLY       CLEAR     67  64  90 NW6       29.76R


CTZALL-210800-
CONNECTICUT

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
BRADLEY INTL   CLEAR     66  63  90 N3        29.79F
HARTFORD       CLEAR     69  65  86 NW3       29.79S
PLAINVILLE     SUNNY     67  65  93 CALM      29.79S
BRIDGEPORT     CLEAR     72  65  78 N9        29.79S
DANBURY        CLEAR     71  63  75 W3        29.83S
GROTON         RAIN     N/A N/A N/A MISG      29.76S
NEW HAVEN      CLEAR     73  67  81 NW6       29.79S
CHESTER        CLEAR     68  68 100 NW9       29.79S
MERIDEN        CLEAR    N/A N/A N/A CALM      29.79S
WILLIMANTIC    CLEAR     65  63  93 CALM      29.80R
OXFORD         CLEAR     65  65 100 CALM      29.83R


MEZ002-015-021-024-NHZ003-005-008-011-012-014-VTZ005-008-210800-
NORTHERN NEW ENGLAND

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
PORTLAND ME    CLEAR     63  62  97 NW9       29.73R
BANGOR ME      CLEAR     62  61  96 NW3       29.68F
CONCORD NH     PTCLDY    61  60  97 CALM      29.78R
MANCHESTER NH  CLEAR     65  60  84 NW10      29.75F
NASHUA NH      CLEAR     65  61  87 NW6       29.77S
PORTSMOUTH NH  CLEAR     65  63  91 W7        29.72F
JAFFREY NH     CLEAR     61  60  97 CALM      29.82S
KEENE NH       FOG       61  61 100 CALM      29.81  VSB 1/4
BURLINGTON VT  CLOUDY    65  59  81 N7        29.84S
MT. WASHINGTON FOG       43  43 100 NW37G51     N/A  VSB 0   WCI  31


NYZ052-076-210800-
EASTERN NEW YORK

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
ALBANY         PTCLDY    64  63  96 CALM      29.84R
NEW YORK CITY  PTCLDY    76  61  59 NW13      29.80R


ANZALL-210800-
MARINE OBSERVATIONS

STATION/POSITION TIME  TEMP    WIND        PRES    VSBY  WAVE
                       AIR SEA DIR/SP/G                  HT/PER
                 (UTC) (F)     (DEG/KT/KT) (MB)    (MI)  (FT/S)
BOSTON BUOY      0640   66 65  300/  8/ 10 1007.2S
BUZZARDS BAY     0600          350/ 18/ 19 1006.4F
NANTUCKET SOUND  0640   71 74  350/ 17/ 21 1005.5F
MASS BAY-STELLWA 0530   65     330/  8/  8   N/A    1 7/8
ISLE OF SHOALS   0700   66     280/ 15/ 15 1005.6F
S OF BLOCK IS    0626      73                N/A           3/ 4


......................KEY.........................
  SKY/WX - SKY CONDITION/PRESENT WEATHER
  TMP    - TEMPERATURE IN FAHRENHEIT
  DWPT   - DEWPOINT IN FAHRENHEIT
  RH     - RELATIVE HUMIDITY IN PERCENT
  WIND   - DIRECTION AND SPEED IN MPH
  PRES   - MEAN SEA LEVEL PRESSURE IN INCHES OF HG
  WCI    - WIND CHILL INDEX
  VSB    - VISIBILITY IN MILES
  HX     - HEAT INDEX
  TC     - TEMPERATURE IN CELSIUS
  VRB    - VARIABLE WIND DIRECTION
  N/A    - NOT AVAILABLE          

RTPBOX

Most of Southern New England
National Weather Service Boston/Norton MA
820 PM EDT Sun Jul 20 2025

This is an automated product. These data are preliminary and have
not undergone final quality control by the National Centers for
Environmental Information (NCEI). Therefore, these data are subject
to revision. Final and certified climate data can be accessed at
www.ncei.noaa.gov.

Values represent lows over the last 18 hours, highs over the last
18 hours and precipitation over the last 24 hours.

.BR BOX  0720 ES DH19/TAIRZS/TAIRZI/PPDRZZ

                           Max        Min         24-Hour
ID         Location        Temp       Temp     Precipitation

Eastern Massachusetts...
 BED        Bedford        89    /    70    /    0.19
 BVY        Beverly        84    /    71    /    0.55
 BOS        Boston         87    /    71    /    0.15
 LWM       Lawrence        89    /    70    /    0.25
 EWB      New Bedford      81    /    69    /    0.00
 OWD        Norwood        86    /    69    /    0.26
 PYM       Plymouth        82    /    70    /    0.00
 GHG      Marshfield        M    /     M    /

Cape Cod and the Islands...
 CQX        Chatham        76    /    67    /    0.00
 HYA        Hyannis        77    /    70    /    0.00
 MVY   Marthas Vineyard    76    /    68    /    0.03
 ACK       Nantucket       77    /    65    /    0.06
 FMH       Falmouth        79    /    70    /
 PVC     Provincetown      79    /    70    /

Central and Western Massachusetts...
 FIT       Fitchburg       89    /    69    /    0.13
 ORE        Orange         87    /    70    /    0.01
 CEF      Springfield      90    /    71    /    0.08
 BAF       Westfield       90    /    71    /    0.12
 ORH       Worcester       85    /    67    /    0.04

Rhode Island...
 BID     Block Island      78    /    68    /
 SFZ      Smithfield       84    /    69    /
 UUU        Newport        77    /    70    /      T
 PVD      Providence       81    /    71    /      T
 WST       Westerly        80    /    70    /    0.01

Northern Connecticut...
 BDL   Hartford-Bradley    90    /    71    /    0.87
 HFD       Hartford        90    /    72    /    0.67
 IJD      Willimantic      87    /    70    /    0.79