NWS Forecast Discussion
623
FXUS61 KBOX 220810
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
310 AM EST Wed Jan 22 2025
.SYNOPSIS...
An arctic airmass will persist through tonight with moderating
temperatures Thursday into the weekend although still below normal.
Generally dry conditions are expected through early next week, but
will monitor a weak clipper system that passes to our north on
Sunday and potentially again on Monday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Subsidence behind departing mid level trough combined with high pres
building in from the west will provide abundant sunshine across SNE
today. Exception will be across the outer Cape where some ocean
clouds are expected to develop and can`t rule out a few flurries
here. Otherwise, an exceedingly dry airmass with PWATs below 0.10"
and subzero dewpoints. It will be another very cold day with 925 mb
temps around -15C resulting in highs in the upper teens to lower 20s
across much of SNE. A modest NW breeze will make if feel more like
the single numbers and teens.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Tonight...
Mid level shortwave moves into the Ohio Valley tonight with area of
enhanced mid level moisture bringing increasing cloud cover. While
it will remain rather cold, the cloud cover will limit radiational
cooling and help to keep temps milder than last few nights. Lows
will range through the single numbers, with teens near the coast.
Thursday...
The mid level shortwave moves into SNE from the west with a weak
ocean storm developing well to the south. Mid and high clouds in the
morning are expected to clear out in the afternoon as mid level
drying moves in from the SW. Meanwhile, increasing low level
moisture from the ocean will bring an increase in lower clouds
across the Cape/Islands. While the deeper moisture remains offshore,
a few snow showers are possible in the afternoon for the
Cape/Islands. Airmass moderates with developing SW flow as 925 mb
temps warm from -15C today to -8 to -9C on Thu. Highs will recover
into the mid-upper 20s interior and lower 30s near the coast.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Key Messages:
* Fairly benign conditions, a weak clipper system Sunday may bring a
few snow showers to northwest Massachusetts, and early next week.
* Chilly again Friday night, but the trend overall are for improving
temperatures this weekend into early next week.
Very little changes in the extended and most of this period will
feature benign conditions. High pressure remains in play for Friday
into Saturday, 1030mb high centered across the eastern third of the
CONUS, resulting in dry conditions. Temperatures trend seasonable,
though are a few degrees below the climatological normal. Highs for
both days are in the upper 20s to low 30s, Friday night will be
colder in the single digits and teens near the coast. Saturday night
temperatures are nearly 10 degrees warmer in the upper teens to
middle 20s.
A weak clipper moves across northern New England on Sunday, but, the
better forcing and moisture (limited at best) is focused across
northern New England. Best chance for any light snow showers would
be focused in northwestern Massachusetts and maintained low POPs in
the `slight chance` category. Monday into Tuesday appears slightly
more active, guidance supports multiple rounds of weak clippers and
shortwave energy moving down from northwestern Canada into northern
New England Monday afternoon and Tuesday. Should have little or no
impacts to southern New England. One wrinkle, whether or not a weak
southern stream system phases with a northern stream clipper on
Monday and bring a few snow/rain showers on Monday. Will say, most
guidance doesn`t support this, although the GFS does bring it some
what close. At this point, no concerns but could be worth watching.
Temperatures climb a few degrees higher than those experienced over
the weekend, highs topping out in the middle to upper 30s Sunday,
Monday, and Tuesday. Nightly lows are still chilly, although is not
to the extent we experienced early this week, forecast lows range
between the upper teens across the interior and low/middle 20s at
the coast.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
06z TAF Update:
Through 12z...
Light snow with MVFR and local IFR conditions from HYA-ACK will
improve to VFR 08-09z as snow ends. VFR elsewhere. Light wind.
Today....High confidence.
VFR, with 4-5k ft cigs developing over outer Cape and ACK. Low
risk for MVFR cigs east of HYA. NW wind 5-15 kt.
Tonight...High Confidence
VFR with mid level clouds moving in. Low risk for MVFR cigs
possible east of HYA. Light to calm wind becoming light SW after
midnight.
Thursday...High confidence.
VFR cigs with patchy MVFR possible over Cape/Islands. SW wind
around 10 kt.
KBOS TAF...High Confidence in TAF.
KBDL TAF...High Confidence in TAF.
Outlook /Thursday Night through Sunday/...
Thursday Night through Friday Night: VFR.
Saturday through Sunday: VFR. Breezy.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High- greater than 60 percent.
Today and tonight...
N wind 15-20+ kt this morning will diminish this afternoon with
light SW winds developing tonight. Seas below SCA. Areas of light
freezing spray this morning.
Thursday...
Increasing SW winds 10-20 kt with a risk for a few 25 kt gusts over
NE MA waters.
Outlook /Thursday Night through Sunday/...
Thursday Night through Friday: Winds less than 25 kt. Seas
locally approaching 5 ft.
Friday Night: Winds less than 25 kt.
Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.
Saturday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 25 kt. Seas up to 5 ft.
Sunday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Seas up to 5 ft.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Cold Weather Advisory until 10 AM EST this morning for MAZ002-
008-009.
RI...None.
MARINE...None.
&&
$$
SYNOPSIS...KJC/Dooley
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...Dooley
AVIATION...KJC/Dooley
MARINE...KJC/Dooley
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