BOX issues Area Forecast Discussion (AFD) at Dec 31, 6:49 AM EST960
FXUS61 KBOX 311149
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
649 AM EST Tue Dec 31 2024
.SYNOPSIS...
Dry conditions and above normal temperatures expected Tuesday. Our
next system arrives Tuesday night, bringing rainfall across southern
New England. Low pressure lifts northeast of our region Wednesday
morning...but a few showers may linger into the afternoon with one
more day of relatively mild temperatures. Otherwise...temperatures
will progressively trend colder/below normal Thursday through the
upcoming weekend. A period of strong to damaging wind gusts are
possible Thursday, as the initial surge of colder air works into the
region. Dry weather will generally prevail Thursday through the
weekend, outside of a brief spot snow shower or two.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM update...
Key Messages:
* Another day of above normal temps
Relatively mild morning in progress, with temps in the 30s to
lower 40s along the coast. Some locations away from the
coastline are at or below freezing. This combined with some
residual moisture from Monday's rains, is resulting in isolated
areas of black ice, especially untreated surfaces. Thus, use
caution over the next few hours.
Otherwise, very pleasant weather today to close out the month of
Dec. Short wave ridging through the column provides abundant
sunshine this morning and temps rising fairly rapidly in the
upper 40s and lower 50s early this afternoon. Given light winds,
it will feel mild. Sunshine will give way to increasing clouds
this afternoon, as WAA pattern advects into SNE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Key Messages:
* Round of heavy rain and perhaps a few embedded t-storms very
late tonight into early Wed
Tonight:
The "action" happens Tuesday evening/early Weds AM with the
arrival of the next system. An upper level shortwave and surface
low will bring another period of rainfall to southern New
England. Warm advection and weak lift combined with precipitable
water values 200-240% of normal will support another soaking
rain to the region. The bulk of the precipitation is likely to
occur late tomorrow night through Wednesday morning. Given
warmer temperatures, this will fall as rain.For rain
amounts(QPF), a good portion of ensemble members are still
hovering in the 0.5 to 1 inch range. Can't rule out a rumble of
thunder as high resolution guidance shows marginal instability
in place.
Wednesday...
Low pressure in the vicinity of the I-95 corridor early Wed morning
will be intensifying as it lifts into Maine later Wed. There will be
lingering showers Wed morning and perhaps even a rumble or two of
thunder early in the morning with some elevated instability.
Otherwise...with lingering shortwave energy a few showers may
persist into the afternoon and evening but not a washout. There
could even be a bit of wet snow mixed in late Wed/Wed evening across
the high terrain...but not expecting much of an impact. Highs should
be in the middle 40s to the lower 50s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
315 AM update...
Key Messages...
* A few showers linger Wed with highs mid 40s to the lower 50s
* Strong-Damaging Wind Gusts Possible Thu...Highs upper 30s/lower 40s
* Temps trending colder/below normal Fri through early next week
* Mainly Dry Thu into the Weekend
* Perhaps a period of snow early next week...but low confidence
Synoptic Overview...
Ensembles and deterministic guidance have closed low over the
maritimes Thu and with upstream ridge amplification over the
Rockies, combined with positive height anomaly amplifying over
Greenland/Davis Strait, maritime low undergoes significant
intensification. Resulting well below normal heights over New
England and the northwest Atlantic, will translate to colder than
normal and blustery conditions for SNE beginning Thursday,
continuing through the weekend and into early next week. The core of
the cold air appears to traverse SNE this weekend, with 850 mb temps
down to -14C/-15C, about 10C colder than normal. Then early next
week, a Pacific system emerges out from the MS/TN Valleys toward the
east coast. Current indications from the ensembles are that the
anomalous Newfoundland low would likely suppress the storm track too
far south of New England, keeping snow threat offshore. However,
some deterministic guidance has a storm track closer to SNE. As
previous forecaster mentioned, still 6 days away, plenty of time for
the atmosphere to reconfigure.
Sensible weather/potential impacts...
Thursday...high probability (greater than 60% chance) for west winds
20-30 mph sustained, gusting to 50 mph (wind advisory). Model
soundings continue to show mixing potential up to 60 mph at times.
This is in response to increasing CAA/steepening low level lapse
rates, combined with almost 50 mb pressure difference between
Maritime low (~ 982 mb) and MS/TN Valley high (~ 1030 mb). This
supports the potential (30% to 50% probability) of wind gusts up to
60 mph at times. Highest probs are across northern MA. If wind gusts
reach or exceed 60 mph, there will be a risk for power outages Thu.
No Wind Headlines yet...but thinking we certainly will need them in
future forecast packages. Otherwise, dry weather prevails but it
will be cold and blustery. Only caveat, given strong CAA across the
Great Lakes, lake effect snow showers (LES) may survive eastward
into western MA (Berkshires) and the Worcester Hills of central MA.
Fri/Sat/Sun...cold and dry with core of cold air over SNE this
weekend. Teleconnections support below normal cold with a -NAO/+PNA
pattern. Highs on Sunday may only reach 25-30 with wind chills in
the teens during the daylight hours. A noticeable difference from
our recent mild weather.
Early next week...ensembles suggest anomalous maritime low will
shift/suppress storm track well offshore for cold, dry weather to
prevail across SNE. However, some deterministic guidance tracks
MS/TN Valley low close enough to SNE for potentially some snow,
which includes the 00z UKMET and 12z ECMWF-AIFS. Still 6 days away,
so all simulations are plausible at this time range.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
12z update: no change to previous TAFs. Lower cigs and vsbys
with rain arrive after the late day/evening push. Low prob of
brief -TSRA Wednesday 09z-13z, but too low (10-20% prob) to
include in the TAF for now. Earlier discussion below.
----------------------------------------------------------------
Today...High confidence.
VFR. SW winds 5-10 knots early, becoming light SE late.
Tonight...High confidence.
VFR conditions early this evening deteriorate to lower end
MVFR-IFR conditions after midnight from west to east. This in
response to a shield of heavy rain, and perhaps a few embedded
thunderstorms overnight. Winds becoming E at 5 to 15 knots.
Wednesday...High confidence in trends. Moderate confidence in
timing.
Rainfall comes to an end, with IFR conditions trending to MVFR
into the afternoon.
KBOS TAF...High confidence in TAF.
KBDL TAF...High confidence in TAF.
Outlook /Wednesday night through Friday/
Wednesday Night: Mainly VFR, with areas MVFR possible. Windy
with gusts up to 35 kt. Chance SHRA, slight chance SHSN.
Thursday: Mainly VFR, with local MVFR possible. Strong winds
with gusts up to 45 kt.
Thursday Night: VFR. Windy with gusts up to 35 kt.
Friday through Friday Night: VFR. Breezy.
Saturday: VFR. Windy with local gusts up to 30 kt.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High- greater than 60 percent.
Winds and seas continue to diminish today, before increasing SE
winds develop tonight, then shift S for Wednesday. Seas will
build in response, especially across the outer coastal waters.
Small Craft Advisories continue into today.
Outlook /Wednesday Night through Saturday/...
Wednesday Night: Moderate risk for gale force winds with areas
of gusts up to 45 kt. Rough seas up to 14 ft. Chance of rain
showers.
Thursday: gale force winds with gusts up to 45 kt. Rough seas
up to 14 ft.
Thursday Night: Moderate risk for gale force winds with gusts
up to 40 kt. Rough seas up to 12 ft.
Friday: Moderate risk for Small Craft Advisory winds with gusts
up to 30 kt. Areas of rough seas.
Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Slight chance of snow
showers.
Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas up to 5 ft. Slight chance of snow
showers.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Gale Watch from Wednesday evening through Thursday evening for
ANZ230>237-250-251-254.
Small Craft Advisory until 7 PM EST this evening for ANZ231-
232-250-254>256.
Small Craft Advisory until 7 AM EST this morning for
ANZ233>235-237.
Gale Watch from Wednesday afternoon through Thursday evening
for ANZ255-256.
&&
$$
SYNOPSIS...Belk/Nocera
NEAR TERM...Belk/Nocera
SHORT TERM...Belk
LONG TERM...Nocera
AVIATION...Belk/Nocera
MARINE...Belk/Nocera
Source:
BOX issues Area Forecast Discussion (AFD) at Dec 31, 6:49 AM EST----------------
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!
