BOX issues Area Forecast Discussion (AFD) at Jan 7, 10:22 AM EST560
FXUS61 KBOX 071522
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
1022 AM EST Tue Jan 7 2025
.SYNOPSIS...
Cold temperatures, blustery northwest winds and dry weather
will prevail for much of this week. High temperatures may run
some 10 degrees below normal, and be accompanied by below zero
wind chills for some during the midweek. Our next chance for
precipitation may not appear until this weekend, but uncertainty
remains quite large.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
845 AM Update:
After some early coordination with NWS Albany, and based on
observations at Worcester Airport with gusts to 46 mph, we
opted to issue a Wind Advisory until 10 PM for the gusty
northwest winds. An increasing NWly jetstreak this afternoon and
a low inversion height could generate gusts up to 50 mph
in/around the higher terrain in central and western MA today
into early tonight. Not much impact with this advisory is
expected aside from a few downed branches and some difficult
travel through some of the hills/passes through the Berkshires.
For the vast majority of the area, the winds should just
contribute to lower daytime windchills. Otherwise, forecast
seems to be holding up well with no other changes necessary.
Previous discussion:
Northern stream shortwave and cold front drops south from northern
New England this morning bringing a reinforcing shot of cold air and
gusty northwest winds. 850mb LLJ between 50-60 knots and good
boundary layer mixing will allow 30-40mph wind gusts to mix down to
the surface. There could be some gusts of 40-50 mph, especially
across the Berkshires, for a short period this afternoon. Confidence
was not high enough to issue a Wind Advisory at this time due to the
question of exactly how deep the mixed layer can get with more
clouds than sun today. The strong NW winds will advect in cold air
with highs only in the low to mid-20s. The feel-like temperature
will be much lower than the actual air temperature, only in the low
teens to single digits. Guidance is mainly dry today due to mid and
upper-level dry air, even with the strong forcing from the
shortwave. It is not entirely out of the question that a few
flurries will be seen around the region this morning, but we are
certainly not expecting any accumulating snow.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Gusty NW winds of 20-30mph continue tonight as the pressure gradient
remains tight, sandwiched between high pressure over Eastern Canada
and low pressure out over the western Atlantic. The stratocumulus
begins dissipating with the loss of diurnal heating, but the gusty
winds will make for less than ideal radiational cooling conditions.
Lows will drop into the mid to high teens, with the feels like temp
near 0F.
Another shortwave trough and reinforcing shot of cold air move
through Wednesday, ultimately giving us a rinse and repeat of our
weather from Tuesday. Gusty NW winds of 30-40mph are likely all day
again, but the 40-50mph gusts over the Berkshires look less likely
with a weaker 850mb wind field around 40-50 knots. High temps once
again top out in the low to mid-20s with feels like temps in the
single digits to low teens.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Key Messages...
* Cold and blustery weather continues Thursday, moderating a bit by
Friday into the weekend
* 30-40 mph NW wind gusts likely continue Thursday
* Tracking a potential storm system for the weekend but confidence
that it directly impacts southern New England is low. A miss to
the south appears more likely at this time.
Thursday...
Persistence forecast continues when it comes to sensible weather as
we head into Thursday with the deep northwest flow pattern remaining
in place. This means continuation of the -15C 925 mb temps resulting
in highs reaching the 20s for most. These 20s, though, will feel
more like the teens thanks to continued gusty winds. Placed between
the deepening low over Nova Scotia and a mid level ridge over the
Ohio Valley we'll efficiently mix down a good portion of the 35-45
kt LLJ overhead. Expect gusts once again to reach 30-40 mph.
Friday...
Quieter Friday, with moderating temperatures and decreasing wind
speeds. Both are thanks to progression of the ridge-trough pattern,
shifting further east and placing SNE increasingly beneath a mid
level ridge. This decreases the pressure gradient (hence the
lessening wind), if slowly, so while it won't be as windy on Friday,
gusts 20-25 mph remain likely. A surge of warmer air beneath the
ridge brings 925 mb temps back toward -2C for highs closer to the
mid and upper 30s.
The weekend into next week...
Not much more in the way of clarity when it comes to the potential
system lurking nearby around the Saturday time period. Odds continue
to favor an offshore miss to the south by a coastal storm that is at
this moment merely a trough of low pressure over southern
California. For anyone hoping for a big snow storm, you'll be
rooting for this southern stream shortwave to phase with a second
northern stream shortwave dropping out of western Canada. Over the
past day or so, the GFS has been the only real global model to do
this and strengthen it into a major storm directly over/near the
70/40 benchmark. Other guidance including the ECMWF and UKMET fail
to sync up these pieces of energy and keep the system suppressed to
our south. Focusing on ensemble guidance at this distance, the GEFS
ensemble isn't too enthused, with a swath of 40-50% chance of
3+inches while the EPS ensemble guidance is a shutout with 0% chance
of 3+inches. FWIW, none of the EPS member lows pass over the
benchmark; all are south and east. We will continue to monitor the
possibility, but at this time odds of a high impact winter storm
appear low.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
15z TAF Update:
Today: High confidence.
VFR. Winds will be strong from the NW all day up to 25-35 kt,
up to 40 kt in the high terrain and near coastal areas.
Tonight... High Confidence
VFR and windy. NW gusts of 20-25 knots continue
Wednesday... Moderate confidence
VFR and windy again with NW gusts of 25-30 knots. Strato
cumulus clouds possible again which could bring brief periods of
MVFR
KBOS TAF...High confidence in TAF.
VFR with gusty NW winds of 25-35 knots for much of the TAF
period.
KBDL TAF...High confidence in TAF.
VFR. Gusty NW winds of 20-30 knots for much of TAF period.
Outlook /Wednesday Night through Saturday/...
Wednesday Night through Thursday Night: VFR. Windy with gusts
up to 35 kt.
Friday: VFR. Windy with local gusts up to 30 kt.
Friday Night: VFR.
Saturday: Mainly VFR, with local MVFR possible. Slight chance
SN.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High- greater than 60 percent.
Today through Wednesday... High confidence
Gale warnings remain in effect today through Wednesday and may need
to be expanded into Thursday as strong NW sustained winds of 30
knots with gusts of 35-40 knots are likely. Gale warnings were
expanded to Boston Harbor for today only, while Narragansett Bay
remains in small craft through Wednesday. The strong winds will
bring dangerous seas of 5-10 feet across the open waters this
afternoon.
The strong winds and cold temperatures will bring light freezing
spray concerns through Thursday night.
Outlook /Wednesday Night through Saturday/...
Wednesday Night: Strong winds with gusts up to 35 kt. Rough
seas up to 11 ft. Chance of freezing spray.
Thursday: Strong winds with gusts up to 30 kt. Rough seas up to
9 ft. Chance of freezing spray.
Thursday Night: Strong winds with gusts up to 30 kt. Rough seas
up to 9 ft.
Friday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Local rough seas.
Friday Night: Winds less than 25 kt. Seas locally approaching
5 ft.
Saturday: Winds less than 25 kt. Slight chance of snow.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Wind Advisory until 10 PM EST this evening for MAZ002-004-008-
009-012-026.
RI...None.
MARINE...Gale Warning until 7 PM EST this evening for ANZ230.
Gale Warning until 7 PM EST Wednesday for ANZ231>235-237-250-
251-254>256.
Small Craft Advisory until 7 PM EST Wednesday for ANZ236.
&&
$$
SYNOPSIS...BW/KP
NEAR TERM...Loconto/KP
SHORT TERM...KP
LONG TERM...BW
AVIATION...BW/KP
MARINE...BW/KP
Source:
BOX issues Area Forecast Discussion (AFD) at Jan 7, 10:22 AM EST----------------
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