Waltham, Massachusetts 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

388
FXUS61 KBOX 281958
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
358 PM EDT Sat Jun 28 2025

.SYNOPSIS...
Chances for isolated severe weather this evening and tonight
across far western MA and norther CT. Seasonably warm and dry
for Sunday. Temperatures then warm up into the mid to upper 80s
again early next week. Primary chance for precipitation next
week falls on Tuesday.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Key Messages:

* Isolated severe weather threat late this afternoon across
  western parts of MA and CT.

The warm front is draped just west of Albany, NY early this
afternoon, and is anticipated to settle later today to the north
in central New England with our area well inside of the warm
sector. Cloud cover and drizzle have hung around a little longer
than expected, but starting to finally see some clearing in the
CT River Valley. Temperatures this afternoon will struggle to
reach 75F east of the CT River Valley, while the Valley itself
likely reaching into the low to mid 80s.

Even with the clearing and destabilization beginning across
eastern NY, still not expecting widespread severe storms this
afternoon across southern New England. More likely to see
isolated severe t- storms with the primary hazard being damaging
straight-line winds. SBCAPE remains around 1,200 J/kg and shear
around 30 knots across western MA and northern CT; however,
best forcing doesn`t arrive until 00z/8pm or just after sunset.
Latest hi-res guidance indicates a strong line of storms
entering western Berkshire County, but quickly dying out as it
approaches the CT River.

We will continue to monitor developments throughout the day but
do want to take a moment to echo the importance of being
weather aware. A thunderstorm doesn`t need to become severe to
be deadly. Lightning can occur without a storm reaching severe
limits, and if you can hear thunder, you are close enough to be
struck by lightning.

The cold front moves east overnight, showers and few rumbles of
thunder are possible, though the severe threat will have ended.
Wind shifts from the southwest to northwest, bringing in a
drier airmass and clearing skies. Tonight low temperatures
settle in the upper 60s. As the front is slow to clear the
coastal plain, fog redevelops overnight.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Key Messages:

* Sunny and warm Sunday!

Cold front shifts offshore and northwest flow ushers in a drier
and warmer airmass. Surface high pressure begins to build into
the northeast and remains through Monday. Have subtle mid-level
height increases as well, leading to a dry and mostly sunny
afternoon. With the 925mb temperatures on either side of +20C,
maximum temperatures will reach the mid to high 80s. Dew points
are manageable in the upper 50s across the interior, while the
coastal plain are in the lower and middle 60s.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Key Messages:

Key Points

 * Hot and humid conditions return Monday and Tuesday. Heat
   Advisories may be needed.

 * Strong to severe thunderstorms possible Tuesday.

 * More seasonable weather for Wednesday-Friday.

Hot and humid conditions are expected to return on Monday and
Tuesday as an upper-level ridge builds in with southwesterly
mid- level flow. 850mb temperatures will warm to +18 to +20 C,
which will translate to surface temperatures in the 90s with
full sunshine. With surface flow turning southerly, dewpoints
will rise into the upper 60s for Monday and low 70s for Tuesday.
Heat advisories may be needed on Monday and Tuesday, as heat
index values could reach 95F on Monday and will likely exceed
95F on Tuesday.

500mb shortwave and surface cold front move through sometime
between Tuesday afternoon and Tuesday night. The ingredients for
organized severe thunderstorms will be available on Tuesday,
with surface- based instability between 1000-2000 J/kg and
sufficient 0-6 km shear between 30-40 kts. The main questions
that remain are whether the front arrives before peak diurnal
heating ends and whether cloud cover and early-day warm frontal
precipitation clear out. The primary hazard at this time appears
to be damaging wind gusts with low-level lapse rates of 10
C/km and strong forcing from the cold front. The secondary
threat looks to be heavy rain, with PWATS closing in on 2.5
inches and warm cloud depths around 12 kft. Thinking storm mode
will be a linear line of storms, but cant rule out an isolated
hail or tornado threat should a discrete supercell form out
ahead of the line.

More seasonable weather behind the cold front for the remainder
of the week, with high temperatures in the 80s and dewpoints in
the upper 50s to low 60s. Another shortwave exits the Great
Lakes late in the week that may bring another round of showers
and thunderstorms for Thursday into Friday.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...

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

Tonight... Moderate Confidence.

LIFR/IFR conditions continue through the evening and overnight
period. Scattered TSRA likely to move into far western New
England in the 22z-24z time frame, but still quite a bit of
uncertainty. Have included a PROB30 at BDL and BAF for that
potential. Any TSRA should dissipate as they move eastward, and
believe any threat of precipitation will basically come to an
end 05-07z. A weak front will also be pushing through the region
producing a wind shift to the W/NW.

Sunday & Sunday Night... High Confidence.

IFR conditions begin to improve to MVFR/VFR around 12-15z. NW
winds 8 to 12 kts, up to 15 kts along the Cape and Islands.

KBOS Terminal...Moderate confidence in TAF. IFR/LIFR conditions
through the night. E/SE winds 3-7 kts veer to W/SW and cigs
lift to VFR Sunday morning.

KBDL Terminal...Moderate confidence in TAF. Possible -TSRA
00z-03z. Conditions improve to VFR early Sunday morning. SW
winds 3-7 kts.

Outlook /Monday through Thursday/...

Monday: VFR.

Monday Night: VFR. Slight chance SHRA.

Tuesday: Mainly VFR, with local MVFR possible. Breezy. Chance
SHRA, slight chance TSRA.

Tuesday Night: VFR. Breezy. Chance SHRA.

Wednesday: VFR. Breezy.

Wednesday Night: VFR.

Thursday: Breezy. Slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today and Tonight... High Confidence.

A warm front slowly moves across the southern waters this
afternoon, leading to areas of marine stratus and fog with
patchy areas of reduced visibilities. Tonight into Sunday
morning a cold front will push across the waters with hit-or-
miss showers and thunderstorms. The front slowly clear the
eastern waters Sunday morning, but areas of marine fog could
remain until the front completely clears the coast.

Sunday and Sunday Night... High Confidence.

High pressure builds in for Sunday with northwest winds across
the eastern waters and W/SW winds across the southern waters.

Outlook /Monday through Thursday/...

Monday through Monday Night: Winds less than 25 kt. Local
visibility 1 to 3 nm.

Tuesday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of
rain showers. Local visibility 1 to 3 nm.

Tuesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of
rain showers. Local visibility 1 to 3 nm.

Wednesday: Winds less than 25 kt. Areas of seas approaching 5
ft. Slight chance of rain showers. Local visibility 1 to 3 nm.

Wednesday Night: Winds less than 25 kt. Seas locally
approaching 5 ft. Local visibility 1 to 3 nm.

Thursday: Winds less than 25 kt. Local visibility 1 to 3 nm.

&&

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

&&

$$

SYNOPSIS...KJC/McMinn
NEAR TERM...McMinn
SHORT TERM...McMinn
LONG TERM...KP
AVIATION...McMinn
MARINE...McMinn