BOX issues Area Forecast Discussion (AFD) at Feb 13, 6:51 PM EST
113
FXUS61 KBOX 132351
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
651 PM EST Thu Feb 13 2025
.SYNOPSIS...
A cold front crossing the region early this evening will bring dry,
but windy and colder weather tonight and Friday. Another system
brings a round of wintry precipitation later Saturday into Sunday,
starting as accumulating snow before changing to rain near the coast
and a wintry mix inland. A shot of arctic air follows Monday and
Tuesday along with strong winds.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
645 PM update...
Cold front has moved into western MA and will quickly sweep
across rest of SNE this evening. Front will be followed by wind
shift to W-WNW and increasing gusts. Low clouds will dissipate
with clearing skies as much drier air moves in. Adjusted timing
of stronger wind gusts for somewhat slower fropa.
Previous discussion...
Key Messages...
* Windy & turning colder tonight
* Westerly wind gusts of 35-50 mph with lows upper teens/20s
* Wind Chills of 5 to 15 above zero by daybreak
Low pressure will rapidly intensify tonight as it lifts into the
Canadian Maritimes. This will result in a strong cold front crossing
the region early this evening...scouring out the remaining low
clouds and fog. The increasing pressure gradient will allow windy
conditions to usher in a colder airmass despite skies becoming
partly to mostly clear. 850T fall from between +4C to +8C this
afternoon to between -14C/-15C by daybreak Friday. This will result
in low temps by daybreak in the upper teens across parts of the high
terrain in MA...to mainly the 20s elsewhere. This coupled with the
windy conditions will result in wind chill values dropping to
between 5 and 15 above zero by daybreak.
Speaking of the winds...pretty good pressure rise couplet behind the
cold front this evening with a strong northwest LLJ on the order of
50 to 60 knots. Steepening lapse rates should allow for northwest
wind gusts of 35 to 50 mph this evening. A few places in the high
terrain may even see brief gusts near 55 mph. We opted to extend the
Wind Advisory for all locations generally near and northwest of the
I-95 corridor...underneath the core of the low level jet. We may see
a few brief gusts to advisory criteria across RI/SE MA...but felt it
was too marginal to issue at this time.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Key Messages...
* Mostly sunny, windy & cold Fri with highs upper 20s/lower 30s
* Cold with diminishing winds Fri night
* Lows Fri night mainly in the teens with a few high single digits
Details...
Friday...
Low pressure will continue to intensify Fri as it lifts even further
north across the Canadian Maritimes. This will continue to result in
cold advection with 850T on the order of -15C to -17C. Despite
plenty of sunshine and good mixing...highs should be held in mainly
the upper 20s to the lower 30s. Bufkit soundings show excellent
mixing with very steep 1000 to 850 developing. So we should see a
second burst of wind develop later in the morning into the mid
afternoon. Therefore...we opted to extend the Wind Advisory into Fri
afternoon generally near and northwest of the I-95 corridor. We
expect northwest winds to gust to between 35 and 50 mph. This will
keep wind chills in the teens Fri afternoon.
Friday night...
Large high pressure will build in from the west Fri night. This will
allow for diminishing winds and a good night of radiational cooling.
Model cross sections indicate some high cloudiness may overspread
the region for the second half of the night...but probably will not
have a significant impact on temps. Low temps should bottom out in
the teens with even some single digits in the normally coldest
outlying locations of west/northwest MA.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Key Messages:
* Next system arrives Saturday afternoon bringing snow to start
followed by a transition to ice and rain by mid-morning Sunday.
* Exact snow amounts uncertain but at least advisory level
accumulations (3-6") for much of the region.
* Windy conditions Monday. Below normal temperatures early next
week.
* Watching the potential for a coastal storm Weds - Thurs.
Details:
Saturday and Sunday
Still tracking an active pattern for this weekend as a southern
stream shortwave trough ejects northward ahead of a deep upper level
trough. Ensemble means have shifted the storm track southeast with
time as it moves northeast Saturday through Sunday. There is good
confidence in this being a more amplified system compared to recent
storms. As a result, models are in good agreement in a wide swath of
1+ inch QPF totals 18z Sat - 03Z Mon.
Precipitation likely gets underway later Saturday afternoon. Cold air
in place will result in widespread snow at the onset. Some mesoscale
models indicate the potential for pockets of moderate snow beneath
vigorous warm advection for a period of time late Saturday afternoon
into the evening. Precip will eventually mix with and change to a
wintry mix from south to north as the mid-level warm nose works its
way north Saturday night into Sunday. The northward extent of the
warmest air and plain rain is still in question. With a southern
trend in the modeled storm track there is a chance that areas north
of route 2 maintain sleet and freezing rain for the majority of the
event. Further south, there is better confidence in a quicker
transition from a mix to rain by Sunday afternoon, especially across
the coastal plain. Despite differences in guidance, there is a good
chance for widespread 2-4 to 3-6 inch snowfall totals for
northern CT and most of MA, especially north of the Mass Pike.
There is growing confidence that most of the CWA picks up
advisory-level snow and ice accums. There is even a low
probability of warning-level impacts north of the Mass Pike.
A potent cold front sweeps through Sunday night followed by strong
CAA. While the column will gradually dry out throughout the night, a
few wrap-around rain and snow showers will likely linger, esp across
northern Mass.
Early Next Week:
Little has changed with our thinking regarding the potential for
strong winds on Monday. With strong CAA and a moderate LLJ overhead,
the potential for stronger gusts should be supported. This will
support Advisory/near Advisory winds across the CWA. The GFS even
hinted at the threat for warning level winds across the higher
terrain but this is a low probability scenario at the moment.
Outside of the winds, anomalous cold is likely early next week.
Ensembles indicate well-below average 850 mb(-15 to -20 C)
temperatures overhead early next week. This will set the stage for
below normal temperatures with highs in the 20s by Tuesday. By
Wednesday there are some signs of upper level heights becoming more
zonal which should help moderate temperatures back into the low 30s.
Midweek:
By midweek, models begin to change the longwave pattern over the
CONUS. Several models are hinting at the potential for a coastal low
pressure to ring in the large-scale pattern shift later in the
period. While we are far away from specifics, ensembles have split
into two distinct camps. The GEFS advertise a flatter wave of low
pressure while the EPS show a more robust coastal low for the
Thursday timeframe.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00z TAF Update: High confidence in trends.
Leftover MVFR-IFR cigs will break up and become VFR with
clearing skies 01-03z. VFR tonight and Fri with W/NW winds
gusting to 35kt at times, but as high as 40kt during day Fri
before winds slowly subside Fri night.
KBOS TAF...Moderate confidence. Timing of changes may be off by
1-2 hours, but more confident in clearing 23z-01z. High
confidence in wind forecast.
KBDL TAF...Moderate confidence. Timing of changes may be off by
1-2 hours. High confidence in wind forecast.
Outlook /Saturday through Tuesday/...
Saturday: Mainly VFR, with areas IFR possible. Breezy. Chance
SN.
Saturday Night: Mainly IFR, with local MVFR possible. Breezy.
SN, FZRA, PL.
Sunday: Mainly IFR, with areas MVFR possible. Breezy. RA, FZRA,
PL.
Sunday Night: MVFR/IFR conditions possible. Strong winds with
local gusts up to 40 kt. FZRA likely, chance RA, chance SN.
Washingtons Birthday: VFR. Strong winds with gusts up to 45 kt.
Monday Night: VFR. Windy with gusts up to 35 kt.
Tuesday: VFR. Windy with gusts up to 30 kt.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight and Friday...High Confidence.
Low pressure will rapidly intensify as it lifts northeastward into
the Canadian Maritimes tonight into Friday. This will result in
strong cold air advection developing this evening along with a tight
pressure gradient. Therefore...Gale Warnings are posted across all
waters into Fri for WNW wind gusts of 30-40 knots with even a few
gusts up to 45 knots. Seas will remain rough and we will see some
light freezing spray develop toward daybreak Fri.
Friday night...High Confidence.
Winds/seas will be diminishing as high pressure builds in from the
west. However...we still will need small craft headlines for many
waters into a good portion of the night.
Outlook /Saturday through Tuesday/...
Saturday: Winds less than 25 kt. Chance of snow. Areas of
visibility 1 to 3 nm.
Saturday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Snow, rain, freezing rain. Areas of visibility 1 nm or
less.
Sunday: Moderate risk for Small Craft Advisory winds with gusts
up to 30 kt. Rough seas up to 12 ft. Rain. Local visibility
1 to 3 nm.
Sunday Night: Strong winds with gusts up to 40 kt. Rough seas
up to 14 ft. Chance of rain, freezing rain likely, slight
chance of snow. Local visibility 1 to 3 nm.
Washingtons Birthday: gale force winds with gusts up to 40 kt.
Rough seas up to 14 ft. Freezing spray. Local visibility 1 to
3 nm.
Monday Night: Moderate risk for gale force winds with gusts up
to 40 kt. Rough seas up to 14 ft. Freezing spray.
Tuesday: Strong winds with gusts up to 35 kt. Rough seas up to
12 ft. Freezing spray.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory until 4 PM EST Friday for CTZ002>004.
MA...Wind Advisory until 4 PM EST Friday for MAZ002>016-026.
RI...Wind Advisory until 4 PM EST Friday for RIZ001.
MARINE...Gale Warning until 4 PM EST Friday for ANZ230-236.
Gale Warning until 7 PM EST Friday for ANZ231>235-237-251-255-
256.
Gale Warning until 10 PM EST Friday for ANZ250-254.
&&
$$
SYNOPSIS...KJC/Frank/FT
NEAR TERM...KJC/Frank
SHORT TERM...Frank
LONG TERM...KJC/FT
AVIATION...KJC/FT/JWD
MARINE...KJC/Frank/FT
Source: BOX issues Area Forecast Discussion (AFD) at Feb 13, 6:51 PM EST (https://mesonet.agron.iastate.edu/p.php?pid=202502132351-KBOX-FXUS61-AFDBOX)
----------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!