258
FXUS61 KBOX 131745
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
145 PM EDT Mon Jul 13 2026

.WHAT HAS CHANGED...
A Heat Advisory has been issued Tuesday into Wednesday for much
of southern New England. Heat Indices are likely to reach
100-103 in some areas.

&&

.KEY MESSAGES...

- Dry and comfortable conditions continue today.

- Heat and humidity return midweek. Heat Advisories go into
  effect Tuesday morning through Wednesday evening.

- Periods of unsettled weather possible later this week as an
  upper level trough pushes over the region.

&&

.DISCUSSION...
KEY MESSAGE 1...Dry and comfortable conditions continue today.

Broad high pressure continue to sit of New England today,
pushing offshore later tonight. Some low-end PoPs across
northern and western MA have been included due to the passage of
a weak shortwave trough later this afternoon, but any showers
will be scattered and sub-severe in nature. Otherwise, most
areas will remain dry through the day, and south-southwesterly
flow will allow for temperatures in the mid to uppers 80s with
heat indices in the upper 80s to low 90s.

KEY MESSAGE 2...Heat and humidity return midweek. Heat
Advisories go into effect Tuesday morning through Wednesday
evening.

Broad mid-level high pressure over the Upper Midwest Tuesday
with ridging extending all the way out to New England will bring
a period of rising heat through Wednesday. 850mb temperatures
rise to near +23C by Tuesday evening, allowing for surface
temperatures to soar into the mid 90s across southern New
England both Tuesday and Wednesday. Prolonged southwesterly flow
will also surge dewpoints to near 70. Combined with poor
overnight relief Tuesday night with low temperatures likely
remaining in the mid 70s to near 80 in some areas, Heat
Advisories have been issued across most of southern New England
(excluding the Cape/Islands and eastern slopes of the
Berkshires) for Tuesday morning through Wednesday evening. While
not as intense as the previous stretch of hot weather,
temperatures of this magnitude will still present significant
risks for those working or doing recreation outdoors.

KEY MESSAGE 3...Periods of unsettled weather possible later
this week as an upper level trough pushes over the region.

Ensemble guidance continues to indicate an amplifying upper-
level trough across Quebec later on in the week, allowing cooler
850mb temps around +10C to +13C to prevail. This will help cool
surface temperature to the low to mid 80s by Friday (upper 80s
across the CT River Valley). Several weak shortwaves pushing
through with the trough bring chances for precipitation and
unsettled weather by the end of the week and into the weekend.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

Today and Tonight: High Confidence. Moderate for shower chances.

VFR conditions are expected across all terminals today. SW winds
at 10-15 kts with gusts 20-25kt this afternoon. Winds decrease
after 00Z to some degree, but there is some question if some
terminals may not decouple overnight with winds staying
elevated. If winds do decouple, LLWS may be possible for a few
hours across the SE MA terminals overnight. Due to lower
confidence this has been kept out of the TAF for now, but may be
added for the 00Z TAF update. A few pop-up showers may be
possible across the area, however given the low coverage of
showers has been messages as VCSH or PROB30 for showers this
afternoon through around 00Z.

Tuesday: High Confidence.

VFR. SW winds 10-20 kts with gusts 20-30 kts.

KBOS Terminal...High Confidence.

KBDL Terminal...High confidence.

Outlook /Tuesday through Saturday/...

Tuesday: VFR. Windy with areas of gusts up to 30 kt.

Tuesday Night: VFR. Windy with local gusts up to 30 kt.

Wednesday: VFR. Breezy.

Wednesday Night: VFR.

Thursday through Thursday Night: VFR. Breezy.

Friday: VFR.

Friday Night: VFR. Slight chance SHRA.

Saturday: VFR. Chance SHRA, chance TSRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Through Tuesday...High confidence.

High pressure moves offshore later today with southwest winds
increasing across the coastal waters. SCA have been issued
Tuesday, with gusty southwest winds 25-30 kts across the
southern and eastern waters. Seas will be quite choppy Tuesday
into Wednesday morning as well, with wave heights 5-8 ft
possible across the southern ocean waters and 3-5 ft along the
coastal waters, including Vineyard and Nantucket Sounds.

Outlook /Tuesday through Saturday/...

Tuesday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas up to 5 ft.

Tuesday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Rough seas up to 9 ft.

Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 25 kt. Areas of rough seas.

Wednesday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Slight chance of rain showers.

Thursday: Winds less than 25 kt. Seas locally approaching 5 ft.

Thursday Night through Friday: Winds less than 25 kt.

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

Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.
Slight chance of rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory from 11 AM Tuesday to 8 PM EDT Wednesday for
     CTZ002>004.
MA...Heat Advisory from 11 AM Tuesday to 8 PM EDT Wednesday for
     MAZ003>007-010>021-026.
RI...Heat Advisory from 11 AM Tuesday to 8 PM EDT Wednesday for
     RIZ001>007.
MARINE...Small Craft Advisory from 4 PM to 11 PM EDT Tuesday for ANZ231-
     250.
     Small Craft Advisory from noon Tuesday to 11 AM EDT Wednesday
     for ANZ232-233-235-237-254>256.
     Small Craft Advisory from noon Tuesday to 5 AM EDT Wednesday
     for ANZ234.

&&

$$

DISCUSSION...McMinn
AVIATION...Mensch
MARINE...McMinn