Arlington, Massachusetts 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

552
FXUS61 KBOX 280633
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
233 AM EDT Mon Jul 28 2025

.SYNOPSIS...
Scattered showers will remain possible into early this evening.
Otherwise...the main story will be the return of the dangerous
heat and humidity Monday through Wednesday and Heat Advisories
have been posted for much of the region. A cold front may bring
some scattered showers and thunderstorms sometime Wednesday
and/or Thursday...followed by much cooler/less humid weather
which will persist into next weekend.

&&

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

* Scattered hit or miss showers at times into this evening with an
  isolated t-storm or two possible

* Areas of fog develop tonight and may become locally dense in the
  typically prone spots...lows in the middle 60s to the lower 70s

Details...

Into Tonight...

The steadiest of the showers have now moved into northeast MA as of
early afternoon. We expect this activity to depart over the next 1-2
hours as the initial shortwave departs. However...diurnal
destabilization was allowing scattered showers and thunderstorms to
develop across parts of NY/PA. Modest west to northwest flow aloft
will bring the potential for additional scattered showers this
afternoon into early this evening...but these will be hit or miss
with plenty of dry weather in between. Instability will also be more
limited in our region given the cloud cover...so even if we see an
isolated t-storm or two not expecting severe weather.

Otherwise...drier mid level air will work into the region tonight.
This will allow for some partial clearing to occur...but the low
levels will remain moist with light/calm winds. This will lead to
the formation of fog...some of which may become locally dense in the
typically prone spots. Overnight low temps should bottom out in the
middle 60s to the lower 70s.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/...
Key Messages...

* Sunshine along with the heat & humidity return on Mon

* Highs Mon lower-middle 90s for many away from the immediate coast

* Heat Indices Mon in the middle to upper 90s

Details...

Monday...

Dry NW flow aloft and at the surface will result in plenty of
sunshine for Monday...but also a return of the heat and
humidity. 850T moderate to between +17C/+18C and expect a super
adiabatic atmosphere. This should allow highs to reach the lower
to middle 90s in many locales away from parts of the immediate
coast. We will mix some of the dewpoints out given NW flow...but
still expect heat indices to reach the middle to upper 90s.
Therefore...Heat Advisories continue and we opted to expand them
to the south coast where dewpoints will be higher. We also
extended the Heat Advisories through Wednesday...which will be
discussed in the long term section. The weak pressure gradient
will allow sea breezes to develop along portions of the
immediate coast and hold highs into the 80s across this region.

Monday night...

A ridge of high pressure will be in control of our weather
Monday night. This will result in light/calm winds with low
temps in the 60s to near 70. We may also see some fog develop
again Mon night. We also will need to watch for some more
smoke/haze from distant Canadian Wildfires based on the
HRRR/RAP...but the worst of that may remain to our north.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Key Messages...

* Heat Advisory in effect from 11 AM Monday to 8 PM Wednesday.

* Mostly dry this week with a chance of showers and t-storms Wed/Thu.

* Cooler for the second half of the week.

Ensemble and deterministic guidance continue to indicate that
Tuesday will be the hottest day of the week, with 850mb temps
right around 20C and 925mb temps between 25-27C. Surface temps
will likely be in the mid 90s across southern New England, with
the exception of the low to mid 80s for the Cape and Islands.
Generally W/NW flow and mixing up to near 700mb should allow for
dewpoints to (thankfully) be a little lower than initially
expected... mid to upper 60s Tuesday and upper 60s to low 70s
Wednesday. Regardless, it will still feel more like upper 90s to
near 100 both Tuesday and Wednesday. A Heat Advisory will be in
effect for through Wednesday for much of southern New England
with the exception of the Cape and Islands.

A weak mid-level shortwave is still on track to move through
Tuesday, bringing the chance for isolated to scattered showers
and thunderstorms in the afternoon. Ensemble guidance shows a
more substantial wave moving through sometime in the Weds-Thurs
timeframe. Still quite a bit of uncertainty in the details such
as timing, precipitation chances/amounts. Expecting a much
cooler (and drier) airmass to push into southern New England
once the shortwave moves through, allowing for a break in the
high heat and humidity. Ensemble guidance shows good agreement
with a transition to even below normal temperatures by Friday.
Another high pressure system looks to move into New England, and
bring a return to seasonal temperatures and dry weather for the
weekend.

&&

.AVIATION /06Z 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: Moderate confidence.

Generally MVFR in areas of stratus with areas of mist. IFR for
the Cape/Islands. Can`t totally rule out brief IFR inland or
along the south coast close to PVD early this morning. Winds light
W/WNW.

Monday: High confidence. Moderate (for ACK stratus).

Sub-VFR stratus and patchy mist scatter/dissipate shortly after
sunrise to VFR conditions. Improvements will likely trend a
little slower for the Cape and Islands with potential for the
low clouds/mist to linger around the Cape and Islands into the
early afternoon. North winds 5-10 kt with seabreezes at BOS.
Haze possible from wildfire smoke today.

Monday Night: High confidence.

VFR for most. IFR-LIFR stratus and mist/fog possible for PVD
and Cape/Islands. N winds become light SW tonight.

Tuesday: High Confidence.

VFR. Light W/SW winds with potential for a sea breeze at BOS.

KBOS terminal...Moderate confidence in TAF. Generally VFR with
MVFR stratus nearby with patchy mist. Still some chance at IFR
ceilings to approach BOS from the east after 07z-11z. Higher
confidence in categorical improvement to VFR by 12z. Haze from
wildfire smoke is possible today which may cause slantwise vis
issues in the AM. Seabreezes today around 14-16z.

KBDL terminal...Moderate confidence in TAF. Some chance at IFR
after 07z otherwise VFR. Higher confidence in categorical
improvement to VFR 11-13z. Light northerly winds.

Outlook /Tuesday Night through Friday/...

Tuesday Night: VFR.

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

Wednesday Night: VFR. Chance SHRA, chance TSRA.

Thursday: Mainly VFR, with local MVFR possible. Chance SHRA,
chance TSRA.

Thursday Night: VFR. Breezy. Chance SHRA, slight chance TSRA.

Friday: Breezy. Slight chance SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Tonight through Monday night...High confidence.

A weak frontal boundary will cross the region tonight. A ridge of
high pressure will then setup to our west Monday into Monday night.
The pressure gradient will remain weak enough to keep winds/seas
below small craft advisory thresholds through Monday night.

Outlook /Tuesday Night through Friday/...

Tuesday Night through Wednesday: Winds less than 25 kt.

Wednesday Night: Winds less than 25 kt. Chance of rain showers,
chance of thunderstorms.

Thursday through Thursday Night: Winds less than 25 kt. Chance
of rain showers, slight chance of thunderstorms.

Friday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas locally approaching 5 ft. Chance of rain
showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory from 11 AM this morning to 8 PM EDT Wednesday
     for CTZ002>004.
MA...Heat Advisory from 11 AM this morning to 8 PM EDT Wednesday
     for MAZ003>007-010>021-026.
RI...Heat Advisory from 11 AM this morning to 8 PM EDT Wednesday
     for RIZ001>007.
MARINE...None.

&&

$$

SYNOPSIS...Frank
NEAR TERM...Frank
SHORT TERM...Frank
LONG TERM...McMinn
AVIATION...Mensch
MARINE...Frank/Loconto/McMinn