Lowell, Massachusetts 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

465
FXUS61 KBOX 260909
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
509 AM EDT Sun Jul 26 2026

.WHAT HAS CHANGED...


&&

.KEY MESSAGES...

- Mainly dry conditions expected today. Increased risk for rip
  currents today, mainly for Cape Cod and Nantucket.

- Periodic chances of scattered showers and thunderstorms early
  to mid week next week, potentially lingering into Thursday.
  Increasing potential for heavy rain late Tuesday through
  Wednesday with at least localized flash flooding possible.

&&

.DISCUSSION...
KEY MESSAGE 1...Mainly dry conditions expected today. Increased
risk for rip currents today, mainly for Cape Cod and Nantucket.


Mainly dry conditions expected today with weak high pressure
overhead. Aloft, heights continue to fall today as a mid-level
trough works into the region while a low pressure system passes well
offshore. The only "impact" this system will have the region is
bringing a stream of moisture brushing across mainly the southeast
portions of MA. This has been prevalent in the low level moisture
fields with easterly flow to reinforce it. Model soundings indicate
a shallow layer of moisture at the surface with dry air above.
Indicator for low clouds and perhaps some patchy drizzle in the
highest coverage spots. The area that has the greater risk for
seeing this is Nantucket and perhaps the outer most portion of the
Cape. Aside from the clouds in some areas, it will be a mainly dry
day with a northeasterly breeze for the eastern coastal areas.
Temperatures lean slightly below normal in the upper 70s to low 80s
for the interior and mid to upper 70s in the eastern and coastal
areas. Areas such as Nantucket may struggle to get out of the low
70s today if the clouds stay persistent.

Prolonged easterly component flow will lead to an increased risk for
rip currents today. The greatest risk will be for the east-facing
beaches on Cape Cod and Nantucket; however, there is also an
elevated risk for the south coast and remaining east-facing beaches.
Nantucket was added to the current Rip Current Statement.

KEY MESSAGE 2...Periodic chances of scattered showers and
thunderstorms early to mid week next week, potentially
lingering into Thursday. Increasing potential for heavy rain
late Tuesday through Wednesday with at least localized flash
flooding possible.

A mid-level trough positions across the region through much of the
week. A series of shortwaves embedded in the flow are expected to
progress across the region through the week supporting periodic
chances for showers and thunderstorms.

The first embedded shortwave likely moves through late Monday into
Tuesday. WAA and moist advection occur ahead of the shortwave during
the day Monday resulting in a warmer day in the low to mid 80s and
upper 70s for coastal areas. There is still potential for scattered
showers and thunderstorms late afternoon/evening though guidance is
still lacking agreement on the coverage and convective potential.
This keeps us at probabilities less than 40% still with west/central
southern New England being more favored.

Model guidance has remained generally consistent with a deepening
trough into Tue/Wed with a strong signal for above normal moisture
(120-170% of normal) advecting into the region by Tuesday. Most
deterministic and ensemble solutions have now come on board with the
development of a low pressure system. In many solutions now, the low
pressure is quite anomalous in magnitude for late-July. Combined
with the enhanced forcing from the low, this is a set-up for heavy
rain potential. However, some model guidance has been more
aggressive than others. The ECMWF and its ensemble members have
shown the strongest signal for heavy rain/flash flooding potential
with a stronger low pressure system tracking in the vicinity of Long
Island, toward eastern MA/Cape Cod in many of its solutions. It also
leans on a slower progression of the trough as well. Soundings
exhibit the textbook environment for efficient rain processes with
deep warm cloud depths aligned with instability. ECMWF ens probs
show 40-75% probability for 1+ of rainfall later Tue into Wed and 10-
40% for 2"+ across a good portion of southern New England. The
deterministic guidance over the last 24 hours of runs has showed a
large footprint of 2"+ amounts across the region in that same
timeframe. With weak steering flow this support slow storm motions
of embedded heavy rain and thunderstorms. This combined with
potential for training for training will increase the risk for flash
flooding with more "scattered" occurrences as opposed to an
isolated case or two. While the recent deterministic runs of the
Canadian and GFS have gone more on board with the heavy rain
potential, their ensemble guidance still have shown solutions
leaning toward a weaker low and differing track resulting
leading to lesser rainfall amounts. There is still a signal for
localized heavy rain/flash flooding within these solutions;
however, they are more isolated or localized. There is still
uncertainty; however, we are at least seeing increasing
confidence for widespread rain with at least localized heavy
downpours/flash flooding possible in spots, particularly later
Tue through Wed. Depending on the track of the low, showers may
linger through Thurs.

Temperatures lean seasonably cool to slightly below normal at times
through the week ranging in the mid 70s to low 80s.


&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
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.

VFR for most. Very low chance of some marginal MVFR conditions
across Cape and Island terminals after 08Z with the higher risk
for ACK. Light northerly to variable winds.

Sunday...High confidence overall (Moderate for cigs in east).

VFR for most. A stream of moisture brushes across the Cape and
Nantucket today resulting increased cloud cover. The potential
for MVFR ceilings is still lower confidence, though the higher
risk would be for ACK with periods of MVFR/IFR cigs possible.
Also can`t rule out a deck of lower clouds near the BOS terminal
around 12Z, but this is very low probability at this time.

E winds for the interior 5-10 kts. NE winds for east coast
terminals 8-12 kts few gusts to 20 kts possible for
Cape/Islands.

Tonight...High confidence overall (Moderate for cigs for
Cape/Islands).

If ceilings ended up lowering today for the Cape/Islands, expect
MVFR/IFR cigs to continue overnight for those areas. Greatest
risk for IFR cigs at ACK with patchy FG possible. VFR elsewhere.
Light northerly to VRB winds.

KBOS Terminal...Moderate Confidence in TAF.

Only moderate confidence due to the low end potential for a
patch of lower MVFR cigs to develop offshore of the BOS
terminal 11-14Z this morning. This is very low probability as it
is not showing up on satellite yet. Will have to keep an eye out
for development this morning.

KBDL Terminal...High confidence in TAF.

Outlook /Monday through Thursday/...

Monday: VFR.

Monday Night: VFR. Slight chance SHRA.

Tuesday: Breezy. Chance SHRA, slight chance TSRA.

Tuesday Night through Wednesday: Breezy. SHRA, chance TSRA.

Wednesday Night: MVFR/IFR conditions possible. Breezy. SHRA
likely, slight chance TSRA.

Thursday: Mainly VFR, with local MVFR possible. Breezy. Chance
SHRA, slight 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.

Light winds and seas 1-4 ft through Monday. Increasing winds
and seas for Sunday; however, below SCA. NE winds 10-15 kts
with gusts to 20 kts. Light NE to SE winds Monday.

Seas increase late Tuesday into Wednesday with SCA conditions
becoming more likely from winds and increased seas.

Increased risk for rip currents today with the greatest risk
for the east-facing beaches/coastline.

Outlook /Monday

Monday through Monday Night: Winds less than 25 kt.

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

Tuesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers,
slight chance of thunderstorms.

Wednesday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Rain showers likely, chance
of thunderstorms.

Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers,
slight chance of thunderstorms.

Thursday: Winds less than 25 kt. Areas of rough seas. Chance of
rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents through Monday morning for MAZ022-024.
RI...None.
MARINE...None.

&&

$$

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