Fitchburg, Massachusetts 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

551
FXUS61 KBOX 110706
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
306 AM EDT Fri Jul 11 2025

.SYNOPSIS...
Seasonably warm and humid weather will remain in control of our
weather into the first half of next week. Although there
will be diurnally-driven shower and thunderstorm chances in
western MA and CT Friday through the weekend, most of eastern
MA and RI should remain dry under onshore flow. A frontal system
on Monday offers better chances at showers and thunderstorms
across most of Southern New England. Temperatures then warm up
around the middle of next week, but will have to monitor for
possible unsettled weather off the mid-Atlantic waters.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

Key Points

* Warm and humid today with heat indices in the upper 80s to low
   90s

* Isolated showers and Thunderstorms this afternoon across the interior

The low-pressure system that brought the heavy rain and flooding
yesterday is now well offshore, with drier air aloft moving in for
today. Low clouds and fog should begin to lift and scatter out
quickly this afternoon, and drier air begins to work in this
morning.  With less cloud cover today, high temperatures are
expected to warm back into the mid-to-upper 80s. Dewpoints remain in
the upper 60s to low 70s, resulting in heat indices near 90F. There
will likely be a couple of isolated showers and thunderstorms across
the interior this afternoon as around 1000-1500 J/kg of MLCAPE
builds.  Storms that do form this afternoon will struggle to become
severe with less than 20 knots of sfc-6km shear, weak mid-level
lapse rates under 5C/km, and very dry air above 10kft.  Storms that
do form could still potentially drop heavy rain with PWATS around
1.25 and tall skinny CAPE profiles. Not anticipating flash flooding
like we saw yesterday with short-lived pulse thunderstorms.


&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...

Tonight

Another warm and humid night with lows in the mid-to-upper 60s, due
to dewpoints also in the mid-to-upper 60s. Given the saturated air
and light southerly onshore flow, expecting more low clouds and fog
to form tonight and linger into Saturday morning.

Saturday

Key Points

* Continued warm and humid conditions

* Isolated showers and thunderstorms are possible once again
  across the interior

Very little change in airmass on Saturday as high pressure remains
parked just off shore.  Surface winds turn more easterly as a result
of the high pressure, but with dry air offshore, not expecting low
clouds and fog to stick around all day. High temperatures moderate
slightly, topping out in the low 80s in the east and mid-80s in the
west.  Mid-level flow begins to turn more SW late across western MA
and into NY and VT.  This will help establish a weak convergence
boundary that could bring Isolated showers and thunderstorms to the
interior.  The severe threat still appears limited with little to no
shear, but MLCAPE values between 1000-1500 J/kg again.


&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Key Messages:

* Drier with onshore flow in eastern portion of Southern New England
  this weekend, with diurnally-driven showers/t-storms possible each
  day this weekend in western MA and CT. Still rather humid but
  temps around or slightly cooler than seasonable.

* Better chance at more widespread showers/t-storms Monday, although
  severe weather potential looks limited.

* Turning very warm to hot around mid next week, but monitoring
  possible unsettled weather off the mid-Atlantic coast.

Details:

Sunday:

Overall a pretty similar weather pattern anticipated for this
weekend. Sfc high pressure in the Gulf of Maine forces a period of
onshore ESE flow, while a weakness in the 500 mb height field lends
itself to more unsettled conditions over distant interior Southern
New England. While most of central and eastern MA and RI should end
up seeing drier conditions than not, a daily (mainly mid-aftn to
early evening) risk for scattered slow-moving showers or
thunderstorms are possible for western MA and CT in vicinity of the
weak upper trough and associated with weak upslope flow. With weak
flow aloft and CAPE values around 1500 J/kg, probably not looking at
severe weather with any storms, but lightning and slow-moving
downpours are possible in any storm which develops. Daily evening to
overnight risk for patchy radiation fog and stratus as well. Highs
low to mid 80s (mid/upper 70s Cape and Islands with onshore flow,
with mid/upper 80s for interior Southern New England.

Monday:

Unfortunately Monday offers a better chance at showers and
thunderstorms across a wider portion of Southern New England, as a
stronger shortwave trough in midlevels and an associated sfc front
cross the area during the afternoon to early evening. Wind fields
aloft at a little stronger than during the weekend, though they`re
still better characterized as weak, and instability values are also
on the lower side. Wouldn`t rule out a stronger cell or two but
thinking any storms would be more garden-variety than otherwise.
Highs are generally similar in the mid 80s and still rather humid.

Tuesday through Thursday:

Some uncertainty in the specific details in this period with respect
to the anticipated weather pattern. More specifically the GFS shows
an amplifying ridge over the OH Valley moving eastward. On the other
hand, the ECMWF and the Canadian GEM are weaker/slower to advance
this ridge eastward, instead favoring a weakness in the height
field/troughiness along the mid-Atlantic/northeast US coastline. A
minority of the ECMWF/GEM members even show some diffuse area of
disturbed weather moving northward from the mid-Atlantic/Carolinas.
Temperatures stand to be quite a bit warmer than the weekend/Monday
and it will also be quite a bit more humid too, but there is more
uncertainty on cloud cover/rain chances in this period given the
differences in ensembles. Because of that uncertainty, didn`t really
stray far from the NationalBlend. Highs in the upper 80s to
lower 90s.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...

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

06z TAF Update...

Rest of Tonight: High confidence in TAF/trends, but lower
confidence on visibilities.

Guidance has generally been a bit too pessimistic so far
tonight, so have trended CIGS slightly higher then previous
forecast, but still low end MVFR/IFR with pockets of LIFR for
ORH and the Cape and Islands.

Friday...High confidence in trends but lower confidence in timing.

Given the better then expected CIGS overnight, expecting low
clouds and fog to lift pretty quickly with sunrise, with fog
clearing out by 12z, and IFR cigs lifting to MVFR/VFR around
15z. CIGS remain MVFR with pockets of VFR from time to time.
Expecting isolated showers and thunderstorms to form across
western MA and CT this afternoon.

Friday night...Moderate confidence.

IFR stratus and fog move back in with light SE flow, but how
far north the status deck gets is still uncertain.

Saturday:

VFR/MVFR. Isolated showers and thunderstorms possible once
again, mainly in western MA.

KBOS Terminal...High confidence in TAF/trends but lower on
visbys.

IFR with periods of LIFR possible tonight. Cigs lift to MVFR
with off and on periods of VFR by mid morning. IFR stratus deck
from SE MA may be able to reach the terminal overnight, but
confidence is low.

KBDL Terminal...High confidence in TAF.

MVFR with periods of IFR possible this morning. Other wise VFR
today with periods of MVFR possible through the afternoon. Low
chance for an isolated thunderstorm early this evening.

Outlook /Saturday Night through Tuesday/...

Saturday Night: VFR. Slight chance SHRA.

Sunday: VFR.

Sunday Night: VFR. Slight chance SHRA.

Monday: VFR. Chance SHRA, chance TSRA.

Monday Night: VFR. Slight chance SHRA, slight chance TSRA.

Tuesday: VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

Today through Saturday...High confidence.

Weak pressure gradient will keep winds/seas below small craft
advisory thresholds through Saturday. Main concern for mariners
will be areas of fog through this morning and again tonight.

Outlook /Saturday Night through Tuesday/...

Winds less than 25 kt.

&&

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

&&

$$

SYNOPSIS...Loconto/KP
NEAR TERM...KP
SHORT TERM...KP
LONG TERM...Loconto
AVIATION...KP
MARINE...KP