BOX issues Area Forecast Discussion (AFD) at Oct 15, 2:43 PM EDT212
FXUS61 KBOX 151843
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
243 PM EDT Thu Oct 15 2026
.WHAT HAS CHANGED...
There is a low risk for severe weather Friday between 5 and 11 pm in
the form of strong to localized damaging wind gusts.
&&
.KEY MESSAGES...
- Brief period of showers mainly Fri morning with a lull in the
activity much of Fri afternoon outside of a few spot showers.
Cluster of showers & perhaps a few embedded t-storms with even
a low risk for severe weather between 5 and 11 pm Fri evening.
Windy and much cooler Sat with highs in the lower-middle 50s.
- Chilly night Saturday night with below-freezing low temperatures
away from the coasts.
- Dry with a modest warmup through early next week, though
monitoring coastal storminess near or south of the mid-
Atlantic waters.
&&
.DISCUSSION...
KEY MESSAGE 1...Brief period of showers mainly Fri morning with a
lull in the activity much of Fri afternoon outside of a few spot
showers. Cluster of showers & perhaps a few embedded t-storms with
even a low risk for severe weather between 5 and 11 pm Fri evening.
Windy and much cooler Sat with highs in the lower-middle 50s.
Large high pressure shifts east of the region tonight as an
intensifying low pressure moves across the eastern Great Lakes. This
will allow a return southerly flow of air along with increasing low
level moisture to work northward into the region overnight.
Initially...mainly clear skies/light winds will allow for temps to
fall quickly through the 40s in many locations shortly after sunset
this evening. However...increasing clouds along with developing low
level southeast flow will allow for slowly rising temperatures
toward daybreak.
In addition...the developing southerly LLJ/moisture transport will
increase the forcing for ascent and allow for a cluster of showers
to develop toward daybreak across interior southern New England.
These showers may reach the coastal plain during the early-mid
morning hours. The showers should be fairly numerous especially
across northern MA...but the steady showers should be relatively
short-lived lasting generally 1-3 hours in a given location.
Otherwise...a good portion of Fri afternoon should feature a lull in
the activity. A few spot showers certainly will remain
possible...But much of this period may feature just cloudy skies
with a breezy southerly wind. Despite lots of clouds...strong warm
advection should push highs well into the 60s in many locations
perhaps even near 70 in few spots. Dewpoints reaching or breaking
60+ will result in a bit of humidity too for the middle of October
standards.
The main concern though is between 5 and 11 pm Fri evening as a cold
front crosses the region. There should be roughly a few hundred J/KG
of at least elevated Cape ahead of this front. Strong jet
dynamics/forcing are also depicted ahead of this front with 55-65
knots of effective shear. The high resolution models generally show
a line of showers with perhaps some embedded thunder as the cold
front sweeps across the region. Despite very strong jet
dynamics...instability is meager...so the severe weather potential
is low but brief sub-severe wind gusts of 35-50 mph are still
possible even if the showers do not contain any thunder.
However...if we end up getting just a bit better moisture return off
the relatively warm ocean...the low risk for severe weather could be
realized. The CSU machine learning probabilities as well as the NCAR
HRRR neural network indicate a low risk for severe weather. Again
this is a low probability...but it needs to be watched. The main
risk would be locally strong to damaging wind gusts especially with
fully leafed trees across most locations.
Otherwise...a much cooler airmass works into the region late Fri
night and Saturday on quite gusty NW winds. A few lingering showers
possible into mid-morning Sat near the southeast New England coast.
Otherwise...windy with northwest wind gusts on the order of 25 to 35
mph with a few gusts near 40 mph expected on Sat. Despite skies
becoming partly sunny on Sat...highs will be held in the lower to
middle 50s.
KEY MESSAGE 2...Chilly night Saturday night with below-freezing
low temperatures away from the coasts.
After a cool, dry and blustery Saturday, looking at one of the
coldest nights we've seen to this point in autumn 2026 as broad, and
strong high pressure settles in over the Northeast. It's still a
little unclear how quickly the blustery NW winds from the daytime
hours subside but at least very good radiational cooling conditions
are anticipated. With a likely cool start, should see lows drop into
mid 20s to low 30s range for much of Southern New England except in
the mid 30s for the cities and Cape Cod/Islands. Note that the
frost/freeze program for Southern New England has ended as of
October 11th and not expected to resume again until mid-Spring 2027,
which means freeze/frost headlines won't be issued; however if you
still have plants/crops outside, you'll want to take the necessary
precautions to prevent freeze/frost damage.
KEY MESSAGE 3...Dry with a modest warmup through early next
week, though monitoring coastal storminess near or south of the
mid- Atlantic waters.
The expansive surface high pressure from Saturday night, spanning
from the Southern Appalachians through Southern New England and the
Canadian Maritimes, then governs our weather pattern Sunday through
early next week. This will facilitate a steady warming trend with
slightly above normal temperatures, with mostly clear skies and
strong diurnal temperature ranges (milder days, cool nights).
Looking at highs Sunday in the mid to upper 50s and lows in the 30s.
Highs by early next week rebound back into the middle 60s with lows
in the upper 30s/low 40s.
It should be a largely dry period through Tuesday, though the one
system we'll be monitoring is a closed upper low near the mid-
Atlantic/Carolinas waters, a feature which became detached from the
broader upper level westerlies along the stalled frontal boundary
from Friday night and early Saturday. The general position of this
system is generally agreed upon across the ensemble NWP suite and AI-
based guidance, but there's quite a bit of uncertainty on if we see
any of this moisture come back northward through the governing
ridge. That could bring at least enhanced NE breezes, strongest near
Cape Cod, and possibly some clouds/light rain showers by Tuesday for
southeast New England. But it's very possible it ends up being
mainly dry/remains to our south. Will maintain blended guidance for
the time being until there's more agreement, but for now will
continue to reassess subsequent guidance.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
18Z TAF Update:
Today and Tonight...High confidence.
VFR. Winds currently shifting NE and diminishing to near 10 kts
as the high pressure system takes over. Winds shift SE this
evening, generally around 5 kts, and some higher level clouds
begin to build in overnight.
Thursday Night...Moderate confidence.
Becoming MVFR to IFR with -SHRA moving in from west to east
between 06Z and 12Z. S-SW winds develop with gusts nearing 20 kt
closer to sunrise.
Friday...Moderate confidence.
IFR to LIFR with SHRA. Brief respite from SHRA possible in the
afternoon hours, though low ceilings continue. Will need to
monitor for the risk of some embedded TSRA and convective
features. Gusty S to SW winds up to 30 kt with higher gusts
possible near the coasts and higher elevations.
KBOS Terminal...High confidence in TAF.
KBDL Terminal...High confidence in TAF.
Outlook /Saturday through Tuesday/...
Saturday: Mainly VFR, with local MVFR possible. Windy with
gusts up to 30 kt.
Saturday Night: VFR. Windy with local gusts up to 30 kt. Patchy
frost.
Sunday through Sunday Night: VFR.
Monday: VFR. Breezy.
Monday Night through Tuesday: VFR.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Tonight through Saturday...High confidence.
High pressure moves east of the waters tonight...but winds/seas will
remain below small craft advisory thresholds. Intensifying low
pressure will move across the eastern Great Lakes tonight and then
proceed near the northern New England/Quebec border Fri into Fri
evening. Ahead of this front...strong small craft southerly wind
gusts along with choppy seas will develop early Fri. We have hoisted
small craft headlines for all our waters on Fri.
Behind this cold front...NW wind gusts of 30-35 knots will develop
especially late Fri night into Sat in the CAA pattern. Given it is
marginal...we opted to continue Gale Watch over this time period.
Despite marginal conditions...cold air advection patterns can often
overperform this time of year given relatively warm SST which can
enhance mixing. Either way...strong SCA to gale force wind gusts are
expected with choppy seas.
Outlook /Saturday night through Tuesday/...
Saturday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 30 kt. Rough seas up to 10 ft.
Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Sunday Night: Winds less than 25 kt.
Monday through Monday Night: Winds less than 25 kt. Slight
chance of rain showers.
Tuesday: Winds less than 25 kt. Seas up to 5 ft. Slight chance
of rain showers.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 8 AM to 6 PM EDT Friday for ANZ230-
236.
Gale Watch from Friday evening through Saturday evening for
ANZ230>237-250-251-254>256-280>283.
Small Craft Advisory from 6 AM to 6 PM EDT Friday for
ANZ231>235-237-250-251-254>256.
&&
$$
DISCUSSION...Frank/Loconto
AVIATION...McMinn
MARINE...Frank/Loconto
Source:
BOX issues Area Forecast Discussion (AFD) at Oct 15, 2:43 PM EDT----------------
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