018
FXUS61 KBOX 212009
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
309 PM EST Fri Feb 21 2025

.SYNOPSIS...

Dry weather continues into this weekend as temperatures moderate to
seasonable levels. Above normal temperatures are anticipated for
early to mid week and some locations may reach into the 50s Tuesday
and Wednesday. A few spot showers are possible around Tuesday, then
it gradually turns cooler and more unsettled toward the end of the
week.

&&

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

Key Messages...

* Dry and colder tonight with lows in the single digits and teens.

We`re on the tail end of our last windy day for a while as we`re
sandwiched between the low over Atlantic Canada and a sprawling high
pressure over the central U.S. As both of these features shift east
overnight the pressure gradient will relax allowing the winds to
diminish. This, combined with our clear skies overnight will allow
for efficient radiational cooling, though if winds don`t
diminish quickly enough the effect will be limited. Combined
with 925 mb temps around -10C and the snowpack, this will mean
low temperatures from around 0F in the highest elevations to the
upper teens for the coastal plain.

&&

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

Key Messages...

* Sunny and dry with light winds and highs in the 30s.

High pressure dominates our weather on Saturday as it moves south of
SNE. While keeping skies clear and winds light, this high will also
back winds to the W then SW kicking off warm advection and a
moderation of our airmass. 925 mb temps warm from -10 to -5 which
should result in highs in the mid to upper 30s. That moderating
airmass continues into the overnight hours as temps only drop into
the upper teens to upper 20s.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...

Key Messages:

* Temperatures trending well above normal Tue and Wed with some
  locations possibly reaching the 50s

* Mainly dry through the middle of the week but a few spot showers
  are possible around Tue

* Trending cooler and more unsettled toward the end of the week

Overview...

Solidly positive AO/NAO pattern early next week with lack of high
latitude blocking and near zonal flow across the CONUS will bring a
warming trend early to mid week. Will have to contend with a few
fast moving northern stream shortwaves passing to the north during
this time but moisture and forcing will be limited. Then the pattern
amplifies toward the end of the week as western CONUS ridge
amplifies with downstream trough amplification across the east
leading to a cooler temps and more unsettled weather.

Sensible weather...

Mainly dry weather expected through Wed, although there may be a few
showers at times from Mon night through Tue night as a few
shortwaves rotate through New Eng. Stronger shortwave is Tue/Tue
night with a cold front sweeping through the region with drying on
Wed. Then a pattern change for the end of the week as digging
northern stream energy amplifies the upper trough across the NE. Low
pressure will be approaching from the west but details in track,
timing and potential secondary development is unknown at this time.
Expect a more unsettled pattern toward the end of the week with
increasing risk of some rain and/or snow.

Temperatures...

Seasonable temps Sunday then a pronounced warming trend is expected
Mon through Wed as SW flow develops with warming 925/850 mb temps.
Peak of the 925/850 mb temps is Tue when highs may reach into the
50s in portions of the coastal plain, especially if there is
sufficient sunshine. NBM indicating 40-60 percent probs of temps
over 50F Tue across RI and SE MA. While low level temps are cooling
Wed, favorable W-NW flow behind the front and deeper mixing may
result in another day with highs 50+ in the coastal plain. NBM probs
of 50+ are 20-40 percent on Wed. Confidence in Thu temps is low as a
possible surge in 925 mb temps ahead of next system may be offset by
cloud cover and potential precip limiting how mild it gets. This
will all depend on the timing of this system but it could be another
mild day Thu in the coastal plain with 50 degree temps if system is
slower. Then colder Fri behind this system with temps trending back
to near seasonable.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
Forecast Confidence Levels:

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

18z TAF Update...

This afternoon...High Confidence.

VFR. NW wind gusts between 25 and 30 knots.

Tonight...High Confidence.

VFR. NW winds gradually diminish.

Saturday... High Confidence.

VFR. WNW 5-10 knots shift to the SW in the afternoon.

Saturday night...High Confidence.

VFR. SW winds 5-10 kts.

KBOS TAF...High Confidence in TAF.

KBDL TAF...High confidence in TAF.

Outlook /Sunday through Wednesday/...

Sunday through Sunday Night: VFR.

Monday: VFR. Breezy.

Monday Night: VFR. Breezy. Slight chance SHRA.

Tuesday: VFR. Slight chance SHRA.

Tuesday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.

Wednesday: VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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

This afternoon and tonight...High Confidence.

Strong pressure gradient as a result of intensifying low pressure
passing east of the Maritimes...will generate NW wind gusts of 20 to
30 knots into tonight. Small craft advisories are posted for all
waters. We also expect areas of light freezing spray tonight.

Saturday and Saturday night...High Confidence.

Pressure gradient weakens as high pressure passes to the south of
our waters. This should result in winds/seas below small craft
advisory thresholds.

Outlook /Sunday through Wednesday/...

Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.

Sunday Night through Monday: Winds less than 25 kt.

Monday Night: Winds less than 25 kt. Seas locally approaching
5 ft.

Tuesday through Tuesday Night: Winds less than 25 kt. Areas of
seas approaching 5 ft. Slight chance of rain showers.

Wednesday: Winds less than 25 kt. Areas of seas approaching
5 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ230-
     236.
     Small Craft Advisory until 7 AM EST Saturday for ANZ231-250-
     254>256.
     Small Craft Advisory until 3 AM EST Saturday for ANZ232>235-
     237-251.

&&

$$

SYNOPSIS...KJC/BW
NEAR TERM...BW
SHORT TERM...BW
LONG TERM...KJC
AVIATION...KJC/BW
MARINE...KJC/BW