Woburn Weather Center  68.7°F

Area Forecast Discussion
National Weather Service Boston/Norton MA
200 AM EDT Thu Jun 19 2025

SYNOPSIS
Overcast skies and muggy conditions persist through the rest of
the day with lingering showers pushing across central MA today.
A Heat Advisory is in effect for Thursday with heat indices
ranging from 97 to near 105. There is also a risk for strong to
severe thunderstorms Thursday afternoon as a cold front moves
through. Drier and seasonably warm Friday and Saturday. A multi-
day stretch of significant heat is possible starting early next
week.

.NEAR TERM /THROUGH TODAY/...
Key Messages:

* Overcast conditions remain through the evening with a quick
  round of scattered showers across western MA.

* Muggy again tonight with lows in the upper 60s to low 70s and
  temperatures near 70.

Details:

Another round of scattered showers is moving into western
MA/northwest CT moving NE this afternoon associated with another
weak disturbance in the SW flow aloft. Should only result in a
quick shower... not expecting any lightning/high winds/etc.
Muggy conditions continue through the afternoon and evening,
with little relief expected over the next day or so.

High humidity continues tonight as dewpoints remain in the high
60s, possibly even into the low 70s across the interior,
meaning dewpoint spreads will only be around 1-2 degrees at
most. Broad SW flow continues aloft while moist southerly flow
continues in the lower levels. This is the primary driver behind
the overcast stratus, and will also lead to a wider area of
patchy fog tonight... especially along southern RI, the South
Shore, Cape and Islands.

.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
Key Messages:

* Heat Advisory in effect for tomorrow with temperatures feeling
  like 95-105.

* Scattered strong to severe thunderstorms as soon as 3 PM, but
  more likely between 5 to 9 PM. Damaging straight line winds,
  torrential downpours, and frequent lightning are the main
  concerns.

* Much less humid Thursday night and drying out.

Thursday:

Stratus and fog likely lingers through mid-morning, but should
scatter out/dissipate quickly once the winds start picking up.
Thursday still looks to be quite active, as the eroding of the
cloud cover will lead to a hazy, hot and humid late morning to
midafternoon. A strong cold front associated with a rather
strong frontal system for late-June will also lead to
potentially strong to severe thunderstorms Thursday afternoon.

1... Heat and Humidity...

Without question, Thursday stands to be one of the hottest days
in southern New England up to this point in the summer, and it
will only feel worse with high humidity levels. 850mb
temperatures warm to around +17C-20C on increasing southwesterly
flow. High temperatures should soar into the mid 80s across the
Cape and Islands and into the low to mid 90s across the rest of
the CWA. With the prolonged moist, southerly flow... dewpoints
will hover in the low 70s, making it feel like 97-105 degrees
outside in the CT and Merrimack Valleys as well as the I-95
corridor. It will likely feel like 95-100 degrees across a wider
portion of Southern New England (excluding the south coast/Cape
Cod where it may feel closer to 90 degrees). Seabreezes are not
expected as southwesterly surface winds pick up to around 10-15
mph. A Heat Advisory is in effect, and we encourage those to
take appropriate heat-related precautions such as taking
frequent breaks in shaded and air conditioned areas, remaining
hydrated, and checking in on those sensitive to heat such as the
elderly and pets.

The high heat and humidity is not expected to break until the
cold front moves across the area later Thursday evening.

2... Strong to Severe Thunderstorms Late in the Day...

Guidance is indicating 850-500mb lapse rates will be quite
steep, around 8-10 C/km, creating an environment that`s
moderately to strongly unstable. Afternoon MLCAPE values range
around 1500-2500 J/kg, with the highest values in interior
Southern New England. Most guidance indicates a moderate amount
of capping, which should act to suppress convection until the
forcing arrives as a cold front arrives... which leads to one of
the biggest questions in the forecast: there is still some
disagreement as to when the front arrives. We anticipate the
main threat for severe weather to begin after 3 PM in western
New England, and particularly in the 5-9 PM timeframe as a line
of storms.

If any isolated storm were to develop on the prefrontal trough
ahead of the main line of storms in the mid to late afternoon,
it would likely become strong to severe quickly. However, most
guidance (including high-resolution and convection allowing
models) are indicating the main threat forming a line of strong
to severe storms moving in from eastern NY after 5 PM with the
cold front. Of some concern is that flow fields have trended a
little stronger (850 winds now near 50 kt in some models), and
bring deep shear values to around 40 kt. We have high confidence
that the greatest threat for severe weather is west of
I-95/I-495, but some threat is possible towards sunset in the
I-95 corridor, especially if convection can get going earlier in
the afternoon.

Damaging wind gusts continue to be the primary hazard, but with
a linear storm mode and the increased low level windfields, a
brief tornado embedded in the line could exist too. Street
flooding could be possible in isolated instances, but the storms
should be moving along at a good clip. Hail is a secondary risk
as well, but the linear storm mode and the hot airmass might
limit hail growth potential. Included gusty winds, small hail
and heavy downpour hazards in enhanced wording, and messaged as
scattered thunderstorms to bring greater awareness.

Those with plans outside during the afternoon, especially from
the Berkshires/Litchfield Hills eastward to Metrowest, will want
to keep close tabs on the forecast for the afternoon.

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Key Messages:

* Cooler and windy Friday with gusts 25-40 mph.

* Mainly dry Friday. More unsettled for Saturday with shower
  chances.

* Signal for well above normal temperatures early next week with
  potential to reach dangerous/impactful levels.

Friday-Weekend:

Mid level troughing persists over the region Friday with NW
flow aloft. Subsident flow should bring in drier air in place
for Friday which will keep conditions dry for Friday. A 40-55 kt
LLJ positions across southern New England. Model soundings
shows sufficient mixing a little below 850mb which should help
bring down gusty W-NW winds. The ECMWF ensemble EFI shows a
signal for anomalous wind gusts with the stronger signal more
confined to the higher terrain of New England. This means we are
likely to have a gusty day, with lower potential for higher
impact winds for southern New England. Ensemble guidance show
gusts in the 25-40 mph range with the higher end of that range
over the higher elevations (east slope of Berkshires and
Worcester Hills). Temperatures trend lower than Thursday in the
cooler post-frontal airmass with highs in the upper 70s to mid
80s.

Saturday, a mid-level ridge approaches from the west. A weak
piece of shortwave energy rounds the ridge dropping across the
region later Saturday-Saturday night. Combined with higher
moisture, this should bring a more unsettled day. Models show a
weak signal for precipitation with differences with respect to
coverage and timing. Most guidance keeps the higher chances for
scattered showers/few storms for later Saturday. Can`t rule out
a spot shower during the day or even a storm given the marginal
instability (MLCAPE < 500 J/kg).

Sunday through Early Next Week:

Ensemble guidance shows good agreement that an anomalously
strong upper level ridge shifts into the northeast by early next
week. Unsurprisingly, this is coupled with a signal for 850mb
temperatures a couple standard deviations above normal. NAEFS,
ECMWF EFI also displays a strong signal for well above normal
heat. Ensemble guidance also shows a stream of moisture
transporting into the region over the top of the upper ridge.
This will help bring in higher moisture air which mean higher
humidity. Another element will be warm temperatures overnight
providing little relief from the hot daytime temperatures.
Together, these elements will raise the risk for heat-related
impacts to those in southern New England.

Rising heat and humidity begins Sunday extending through early
next week. NWS Heat Risk is quite reflective of the rising
temperatures and humidity with values increasing into the
Moderate Category Sunday and into the High Category
Monday/Tuesday for most places. Even the Cape/Islands enter the
Moderate Category by Tuesday. What this means is that early next
week will have a high risk for heat related impacts, especially
to heat sensitive people, urban populations, and those who lack
cooling sources. This is still further out, so stay tuned as
confidence increases in this signal. At this point,
awareness/preparedness are beneficial given the potential for
impactful heat/humidity next week. Find/have a location that
provides cooling/AC and plan more strenuous activities outside
of the hotter parts of the day.

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...

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

06Z TAF Update:

Through 12z Thursday: High confidence in trends, though moderate
on exact timing.

IFR to LIFR stratus and fog has already developed in most
locations but will continue to expand northward through the rest
of the overnight. Possible hit-or-miss shower for the interior
airports thru 10z. Light S winds, calm at times.

Today: High confidence in trends, though moderate on timing.

IFR-LIFR stratus and fog dissipate for most airports between
13-14z; although at least IFR is likely to continue over the
Cape and Islands much of the day. VFR with hazy conditions once
stratus dissipates.

Focus then turns to strong to severe TSRA potential for the
afternoon to early evening. Growing consensus in scattered to
numerous t-storms between 18-23z for BAF-BDL-HFD-ORH corridor,
some which may turn severe. Have hit these airports the hardest,
with prevailing VCTS with TEMPO 2 SM +TSRA in the
aforementioned timeframe. It`s still a question if BOS, PVD and
BED sees t-storms but the potential seems to be on the increase,
best chance between 22-00z. Maintained PROB30s for these TAFs,
and later TAF issuances could increase the t-storm potential
here. Damaging wind gusts and torrential downpours are the
primary severe-storm hazards. SW winds increase to around 10 kt
by late this morning, with developing gusts to 20-25 kt during
the afternoon.

Tonight: High confidence.

A low chance for lingering TSRA thru 02z but improvement is
expected at all airports. IFR stratus and fog out over the Cape
and Islands may still linger until we see a gusty westerly
windshift overnight. SW to W winds increase to around 10-15 kt
with gusts low-20s kt range, with possible LLWS for the Cape and
Islands from a 40kt westerly low level jet.

Friday: High confidence.

VFR. W/WNW winds become gusty by late morning, with speeds
13-18 kt and gusts 25-35 kt.

KBOS Terminal...Moderate confidence in TAF.

IFR ceilings scatter to VFR after 14z, with possible HZ due to
very humid air. Monitoring for possible TSRA 22-00z; while
confidence is still lower on occurrence, the potential continues
to increase. Maintained PROB30 -TSRA for now. SW winds becoming
10-13 kt today with gusts 20-23 kt, with a windshift to W
overnight at similar speeds.

KBDL Terminal...Moderate confidence in TAF.

IFR ceilings scatter to VFR 13-14z, with possible HZ due to very
humid air. Greater potential for TSRA/+TSRA between 18-23z and
indicated VCTS starting 18z with TEMPO 2SM +TSRA 19-23z due to
growing confidence. Damaging winds, frequent lightning and heavy
downpours all threats in +TSRA. S winds around 10-12 kt with
gusts to 20 kt today, then with a windshift to W around midnight
at similar speeds.

Outlook /Friday Night through Monday/...

Saturday: VFR.

Saturday Night through Sunday: VFR. Breezy. Chance SHRA, slight
chance TSRA.

Sunday Night: VFR.

Monday through Monday Night:

Tuesday: Breezy.

.MARINE...
Forecaster Confidence Levels...

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

Winds and seas through Wednesday night should remain below small
craft advisory thresholds. S winds around 10-15 kt with seas
around 4 ft or less. Small craft advisory in effect for Thurs
and Fri both from building seas near 5 ft and SW winds around
25-30 kt.

Foggy conditions again tonight. Potential for strong to severe
thunderstorms in the nearshore waters late Thursday evening into
the overnight period.

Outlook /Friday Night through Monday/...

Saturday: Winds less than 25 kt.

Saturday Night: Winds less than 25 kt. Slight chance of rain
showers.

Sunday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Slight chance of rain showers.

Sunday Night through Monday: Winds less than 25 kt. Seas
locally approaching 5 ft.

Monday Night through Tuesday: Winds less than 25 kt.

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for CTZ002>004.
MA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for MAZ003>007-010>019-026.
RI...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for RIZ001-002.
MARINE...Small Craft Advisory from 4 PM this afternoon to 8 AM EDT
     Friday for ANZ250-254>256.

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
103 AM EDT Thu Jun 19 2025

Forecast Synopsis
Overcast skies and muggy conditions persist through the rest of
the day with lingering showers pushing across central MA today.
A Heat Advisory is in effect for Thursday with heat indices
ranging from 97 to near 105. There is also a risk for strong to
severe thunderstorms Thursday afternoon as a cold front moves
through. Drier and seasonably warm Friday and Saturday. A multi-
day stretch of significant heat is possible starting early next
week.

Southeast Middlesex MA-
Including the city of Cambridge
103 AM EDT Thu Jun 19 2025

...HEAT ADVISORY REMAINS IN EFFECT FROM 11 AM TO 8 PM EDT
THURSDAY...

.REST OF TONIGHT...Mostly cloudy. Patchy fog. Near steady
temperature in the upper 60s. South winds around 5 mph.
.THURSDAY...Partly sunny in the morning, then clearing. Patchy
fog in the morning. Much warmer. Humid with highs in the mid 90s.
Southwest winds 5 to 10 mph. Gusts up to 20 mph in the afternoon.
Heat index values up to 103 in the afternoon.
.THURSDAY NIGHT...Partly cloudy. Humid with lows in the upper
60s. Southwest winds around 10 mph with gusts up to 20 mph.
.FRIDAY...Sunny. Not as warm with highs in the lower 80s. West
winds 10 to 15 mph with gusts up to 30 mph.
.FRIDAY NIGHT...Mostly clear. Lows in the mid 60s. West winds
5 to 10 mph. Gusts up to 20 mph in the evening.
.SATURDAY...Mostly sunny. Highs in the mid 80s.
.SATURDAY NIGHT AND SUNDAY...Mostly cloudy. A chance of showers.
Lows in the upper 60s. Highs in the upper 80s. Chance of rain
30 percent.
.SUNDAY NIGHT THROUGH MONDAY NIGHT...Partly cloudy. Hot. Lows in
the lower 70s. Highs in the mid 90s.
.TUESDAY AND TUESDAY NIGHT...Mostly clear. Hot. Highs in the
upper 90s. Lows in the mid 70s. Heat index values up to 105.
.WEDNESDAY...Partly sunny with a chance of showers. Hot with
highs in the mid 90s. Temperature falling into the upper 80s in
the afternoon. Chance of rain 30 percent.          

REGIONAL WEATHER ROUNDUP
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
200 AM EDT THU JUN 19 2025

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

MAZALL-190700-
EASTERN MASSACHUSETTS

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
BOSTON         MOCLDY    68  67  96 SW3       29.83F
6HR MIN TEMP:  67; 6HR MAX TEMP:  75;

BEVERLY        CLOUDY    67  66  97 CALM      29.83F
LAWRENCE       CLOUDY    70  68  93 SW3       29.85F
BEDFORD          N/A    N/A N/A N/A MISG        N/A
NORWOOD        CLOUDY    71  68  90 S5        29.84F
MARSHFIELD     CLOUDY    70  68  94 SW5       29.84F FOG
PLYMOUTH       FOG       67  66  97 CALM      29.84F VSB 1/2
TAUNTON        CLOUDY    67  66  97 SW3       29.85F FOG
NEW BEDFORD    FOG       67  66  97 CALM      29.85F VSB 1/2


MAZALL-190700-
CAPE COD AND THE ISLANDS

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
FALMOUTH       FOG       64  64 100 S6        29.87F VSB 1/4
HYANNIS        FOG       65  65 100 S7        29.84F VSB 1/2
CHATHAM        FOG       63  63 100 SW5       29.85F VSB 1/2
PROVINCETOWN   CLOUDY    65  65 100 S9        29.85F FOG
NANTUCKET      FOG       62  62 100 SW10      29.86F VSB 1/4
MARTHAS VNYRD  FOG       63  63 100 S5        29.85F VSB 1/4


MAZALL-190700-
CENTRAL AND WESTERN MASSACHUSETTS

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
WORCESTER      FOG       68  67  96 W6        29.86F VSB 1
6HR MIN TEMP:  67; 6HR MAX TEMP:  72;

FITCHBURG      MOCLDY    68  67  96 CALM      29.85F
ORANGE         CLOUDY    70  68  93 CALM      29.85F
SPRINGFIELD    CLOUDY    71  69  95 S3        29.80F
WESTFIELD      CLOUDY    71  70  96 S6        29.83F
NORTH ADAMS    MOCLDY    71  69  93 SE3       29.83F
PITTSFIELD     CLOUDY    70  69  97 CALM      29.84F


RIZALL-190700-
RHODE ISLAND

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
PROVIDENCE     FOG       65  65 100 S3        29.85F VSB 1/4
6HR MIN TEMP:  65; 6HR MAX TEMP:  67;

NEWPORT        FOG       63  63 100 CALM      29.85F VSB 1/2
BLOCK ISLAND   FOG       63  63 100 SW5       29.85F VSB 3/4
SMITHFIELD     FOG       67  50  55 CALM      29.86F VSB 1/4
WESTERLY       FOG       64  64 100 CALM      29.85S VSB 1


CTZALL-190700-
CONNECTICUT

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
BRADLEY INTL   CLOUDY    71  70  96 S7        29.84F
6HR MIN TEMP:  71; 6HR MAX TEMP:  75;

HARTFORD       CLOUDY    70  69  97 S6        29.83F
PLAINVILLE     CLOUDY    70  70 100 S3        29.84S
BRIDGEPORT     CLOUDY    66  66 100 E3        29.84F FOG
DANBURY        CLOUDY    70  68  93 CALM      29.85F FOG
GROTON         FOG       65  65 100 SW3       29.85R VSB 1/2
NEW HAVEN      FOG       68  67  96 CALM      29.84F VSB 1/4
CHESTER        FOG       68  68 100 CALM      29.87S VSB<1/4
MERIDEN        CLOUDY    70  69  97 S5        29.84F
WILLIMANTIC    CLOUDY    68  68 100 S3        29.86S FOG
OXFORD         FOG       67  50  55 SE3       29.87F VSB 1/4


MEZ002-015-021-024-NHZ003-005-008-011-012-014-VTZ005-008-190700-
NORTHERN NEW ENGLAND

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
PORTLAND ME    FOG       60  60 100 CALM      29.85F VSB 1/2
6HR MIN TEMP:  59; 6HR MAX TEMP:  65;

BANGOR ME      FOG       61  61 100 S5        29.86F VSB 1
CONCORD NH     CLOUDY    68  67  96 CALM      29.84F
MANCHESTER NH  PTCLDY    67  66  97 CALM      29.82F
NASHUA NH      MOCLDY    68  68 100 CALM      29.84F
PORTSMOUTH NH  PTCLDY    66  65  96 CALM      29.82F
JAFFREY NH     CLOUDY    69  68  96 SW3       29.87F
KEENE NH       CLOUDY    70  69  97 CALM      29.84F
BURLINGTON VT  NOT AVBL
MT. WASHINGTON MOCLDY    54  52  94 SE9         N/A


NYZ052-076-190700-
EASTERN NEW YORK

CITY           SKY/WX    TMP DP  RH WIND       PRES   REMARKS
ALBANY         CLOUDY    73  71  93 SE5       29.80F
6HR MIN TEMP:  73; 6HR MAX TEMP:  78;

NEW YORK CITY  PTCLDY    69  65  86 CALM      29.82F
6HR MIN TEMP:  69; 6HR MAX TEMP:  78; 6HR PCP: TRACE;



ANZALL-190700-
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      0540   62 61  190/  6/  8 1010.8F
BUZZARDS BAY     0500          200/  8/  9 1011.8F
NANTUCKET SOUND  0540   64 64  210/  8/ 12 1010.3F
MASS BAY-STELLWA 0530   63     180/  6/  8   N/A     5/16
ISLE OF SHOALS   0500   65     200/ 11/ 11 1010.1F
S OF BLOCK IS    0556      61                N/A           3/ 6


......................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 Wed Jun 18 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  0618 ES DH19/TAIRZS/TAIRZI/PPDRZZ

                           Max        Min         24-Hour
ID         Location        Temp       Temp     Precipitation

Eastern Massachusetts...
 BED        Bedford        77    /    66    /    0.00
 BVY        Beverly        65    /    64    /    0.02
 BOS        Boston         78    /    65    /      T
 LWM       Lawrence        77    /    66    /    0.04
 EWB      New Bedford      77    /    65    /    0.01
 OWD        Norwood        79    /    67    /      T
 PYM       Plymouth        77    /    64    /    0.01
 GHG      Marshfield       77    /    64    /

Cape Cod and the Islands...
 CQX        Chatham        67    /    60    /    0.00
 HYA        Hyannis        69    /    63    /      T
 MVY   Marthas Vineyard    68    /    62    /      T
 ACK       Nantucket       65    /    59    /      T
 FMH       Falmouth        73    /    63    /
 PVC     Provincetown      74    /    63    /

Central and Western Massachusetts...
 FIT       Fitchburg       77    /    66    /      M
 ORE        Orange         75    /    65    /    0.06
 CEF      Springfield      80    /    64    /    0.10
 BAF       Westfield       78    /    64    /    0.10
 ORH       Worcester       74    /    62    /    0.03

Rhode Island...
 BID     Block Island      69    /    60    /
 SFZ      Smithfield       79    /    62    /
 UUU        Newport        71    /    62    /    0.02
 PVD      Providence       74    /    62    /    0.02
 WST       Westerly        71    /    61    /    0.02

Northern Connecticut...
 BDL   Hartford-Bradley    77    /    63    /    0.07
 HFD       Hartford        76    /    63    /      T
 IJD      Willimantic      76    /    62    /    0.01