ct discuss
Office: BOX
FXUS61 KBOX 021800
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
100 PM EST Tue Dec 2 2025
.SYNOPSIS...
A winter storm will bring accumulating snow across interior southern
New England into tonight...particularly north of I-90 into the high
terrain where precipitation remains mainly snow. Mainly rain is
expected near I-95 and even for a time across the interior southern
New England south of I-90...before a transition back to snow occurs
later tonight. All precipitation should have come to an end by
daybreak Wednesday. Beyond that high pressure brings dry weather to
end the week except for a moisture starved front Thursday bringing a
few snow showers. Arctic airmass bring well below normal
temperatures Thursday night, Friday, and Friday night.
&&
.NEAR TERM /THROUGH TONIGHT/...
Key Messages...
* Winter Storm continues tonight across interior southern New
England especially north of I-90 and the high terrain
* 1-2" per hour snowfall rates north of I-90 and especially near
route 2 make for hazardous travel for the evening commute
* Mid level warm layer moving northward will result in Ptype
transitioning to a period of rain south of I-90 even across the
interior through the mid to late afternoon hours
* Narrow swath of sleet and freezing rain for a time into
northern CT and possibly interior southern MA
* Mainly rain along the I-95 corridor into RI that should transition
to a period of snow before ending toward daybreak
* Total snow accumulations of 6-10" in the highest terrain of
northern MA...2-5" in the lower elevations of western/central
MA...and mainly a dusting to 2" across CT/RI & eastern MA
Details...
This afternoon into tonight...
Low pressure will be intensifying as it moves off the mid Atlantic
coast and tracks just inside the Benchmark this afternoon into this
evening. Thermal profiles are initially cold enough for mainly snow
northwest of the I-84/I-495 interchange inland from the coastal
front into mid afternoon. However...given the lack of cold high
pressure across eastern Canada and the mid level centers tracking
northwest of the Benchmark will allow warmer mid-level air to move
northward. Therefore...an initial burst of snow through early
afternoon will change to mainly rain south of I-90 by mid-late
afternoon. A few inches of snow may occur in this region before the
transition to rain across southwest/south central MA perhaps into
far northern CT. There remains some uncertainty how far north this
mid level warm layer will reach before stalling out...but we are
thinking this will mainly stay south of the route 2 corridor and
possibly not make it much further north than I-90. As the mid level
low/s close off and result in strong mid level frontogenesis...we
may see 1-2 per hour snowfall rates this afternoon into early
evening where Ptype remains snow north of I-90 and especially
towards route 2. This will result in significant impact to the
evening commute north of I90 and especially near route 2 corridor.
There also may be a narrow area of sleet and freezing rain on the
edge of the mid level warmth...but should be fairly narrow
swath. We did expand the Winter Weather Advisory into northern
CT to account for this risk. We also may see that narrow band of
sleet and freezing rain into interior parts of southern MA.
Meanwhile...areas south of I-90 as well as along the I-95
should see moderate to heavy rain for the late day commute.
As the mid level low/s shift east of the region...lingering moisture
with temps cooling aloft should allow for many locations to
transition to snow before things wind down before daybreak
Wednesday. A coating to an inch of snow will be possible onto the I-
95 corridor with perhaps 2" into the lower elevations of interior
eastern MA. Further northwest in the lower elevations of
western/central MA...total accumulations of 2-5" seem reasonable.
The highest snowfall amounts of 5-10" should be common across the
northern Worcester Hills/Berks and as well as areas north of route
2. All in all...no changes planned to any of the headlines
except for the expansion of the Winter Weather Advisory into
northern CT.
Lastly...gusty N winds will work into the region on the backside of
the system later this evening and overnight. Gusts of 20-30 mph are
expected overnight with some 35-40+ mph gusts possible across
the outer- Cape/Nantucket. Low temps by daybreak will be in the
20s across the interior...with lower to middle 30s along the
I-95 corridor and middle to upper 30s near the Cape and Islands.
So not expecting many issues with roads along and southeast of
I-95 corridor...but northwest of I-95 untreated roads will be
slippery for the Wed am commute despite the precipitation having
ended.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Key Messages:
* High pressure builds in following the exit of the coastal storm,
leading to cooler, drier weather
The low responsible for the active weather to start the week exits
heading into Wednesday morning and high pressure moves in behind it.
High temperatures are not expected to get higher than the low 40s
and mid 30s for the region, with some spots in the higher elevations
struggling to get above freezing. NW winds weaken and shift slightly
more to the W and SW as the day progresses.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Key Messages:
* Scattered snow showers possible Thursday.
* Arctic airmass in place Thursday night-Saturday bringing well
below normal temperatures.
Details...
After a brief period of weak high pressure, a shortwave trough moves
through the region on Thursday accompanied by a strong cold front.
The wave is fairly moisture starved with precipitable water values
0.4-0.6". There should be a brief window with some mid-level
moisture advecting into the region. With the help of the
approaching front, this will provide lift for a few snow
showers during the day Thursday. Ensembles show low-moderate
probabilities for light QPF amounts. With marginal instability
present and approaching arctic front/airmass, global guidance
also hint at snow squall potential. Given limited moisture and
uncertainty in the details of the frontal passage, this will be
lower probability for now. A few convective showers/segments
that may be capable of a localized brief "burst" of higher snow
rates. Overall deterministic/ensemble guidance keeps totals
trace to light if anything given the localized nature of the
showers.
An arctic airmass will push in behind the front Thursday night.
850mb temperatures range -15 to -20C with mainly clear skies.
Despite breezy conditions (at least to start the night),
temperatures will likely plummet into the single digits for the
interior and teens along the coast. These are the coldest
temperatures of the season so far. As mentioned, winds may be
elevated to start the night which will bring wind chill values into
the negative single digits for the higher terrain and single digits
elsewhere. The arctic airmass remains in place for Friday support
high temperatures 10-15 degrees below normal. Highs struggle to
reach 30 degrees, with the exception of SE MA and the south coast in
the mid 30s.
Ensemble guidance shows a consensus for a transition to a more
active pattern heading into the weekend. There is a signal for a
coastal system to brush the region sometime late Friday-Saturday.
Details still less certain this far out, but this could bring
another round of precipitation to southern New England. Once timing
and track become more clear, we will get a better idea of precip
type (snow or mix/rain event).
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
18Z update...
Today...Moderate Confidence.
MVFR ceilings drop to IFR-LIFR as precip overspreads the region
this afternoon, 18-21z. Ptype rain for coastal terminals. SN
to start for BDL,BAF, BED, and ORH, with chance for RA to mix
in the afternoon 19z-21z. Lower confidence for precipitation
type due to uncertainty in location of rain-snow line. E-NE wind
5-15 kt. Minor accumulations for BDL, BAF, BED, and ORH. 2-6"
possible depending on where RA- SN line positions. Snowfall
rates less than 0.5"/hour for terminals.
Tonight...Moderate confidence.
Widespread IFR-LIFR improving to VFR late from west to east
after 06Z. Light SN for interior terminals in evening. Change
over to a period of light RA/SN or light SN possible along the
I-95 corridor, including BOS and PVD for a short period. Timing
of change over is lower confidence, but would be after 03Z.
Minor accum (Trace-0.5") possible at BOS. NE wind becoming N-NNW
with gusts to 25 kt developing, with 30-40 kt gusts possible
for Cape/Islands.
Wednesday...High Confidence.
VFR. NW winds with gusts up to 22 kts (up to 25 kts for
Cape/Islands) in the morning decreasing in the afternoon.
KBOS Terminal...Moderate confidence in TAF.
Changeover to -RASN or -SN possible Tuesday night. Exact timing
lower confidence, more likely between 03-07z.
KBDL Terminal...Moderate confidence in TAF. Lower confidence in
timing of ptype changes.
Outlook /Thursday through Saturday/...
Thursday: VFR. Windy with areas of gusts up to 30 kt. Slight
chance SN.
Thursday Night: VFR. Windy with gusts up to 30 kt.
Friday: VFR.
Friday Night: VFR. Slight chance SN.
Saturday: VFR. Chance RA, slight chance SN.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Today through Tuesday Night... High confidence.
Rain overspreads the waters and SSE winds early increase and
turn out of the east then northeast late as a low pressure
system crosses the southern waters. Gusts to 30-35 kts become
possible tonight over the eastern waters, and around 25- 30 kts
for the southern waters. Seas become rough as well, approaching
8-9 ft. Gale Warning starting 7 PM tonight through the
overnight hours for the eastern waters, while a Small Craft
Advisory is issued for the southern waters.
Seas and winds begin to diminish heading into Wednesday as high
pressure moves in over the waters.
Outlook /Thursday through Saturday/...
Thursday: Low risk for gale force winds with gusts up to 35 kt.
Areas of rough seas.
Thursday Night: Low risk for gale force winds with gusts up to
40 kt. Rough seas up to 10 ft.
Friday: Winds less than 25 kt. Seas locally approaching 5 ft.
Friday Night: Winds less than 25 kt. Slight chance of rain.
Saturday: Winds less than 25 kt. Chance of rain.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory until 7 AM EST Wednesday for CTZ002-
003.
MA...Winter Weather Advisory until 7 AM EST Wednesday for MAZ005-
006-010>012.
Winter Storm Warning until 7 AM EST Wednesday for MAZ002>004-
008-009-026.
RI...None.
MARINE...Gale Warning from 7 PM this evening to 7 AM EST Wednesday for
ANZ230.
Gale Warning from 7 PM this evening to 1 PM EST Wednesday for
ANZ231-232-250-251-254-255.
Small Craft Advisory from 4 PM this afternoon to 7 PM EST
Wednesday for ANZ233>235-237.
Small Craft Advisory from 4 PM this afternoon to 7 AM EST
Wednesday for ANZ236.
Small Craft Advisory from 4 PM this afternoon to 1 AM EST
Thursday for ANZ256.
&&
$$
SYNOPSIS...Frank/Mensch
NEAR TERM...Frank
SHORT TERM...Hrencecin
LONG TERM...Mensch
AVIATION...Frank/Dooley
MARINE...Hrencecin/Mensch
FXUS61 KBOX 021830
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
130 PM EST Tue Dec 2 2025
.SYNOPSIS...
A winter storm will bring accumulating snow across interior southern
New England into tonight...particularly north of I-90 into the high
terrain where significant snow accumulations are expected.
Mainly rain is expected across eastern MA and RI...before a
transition to snow occurs later tonight. All precipitation
should have come to an end by daybreak Wednesday. Beyond that
high pressure brings dry weather to end the week except for a
moisture starved arctic cold front Thursday bringing a few snow
showers. Arctic airmass bring well below normal temperatures
Thursday night, Friday, and Friday night.
&&
.NEAR TERM /THROUGH TONIGHT/...
Key Messages...
* Winter Storm continues tonight across interior southern New
England especially north of I-90 and the high terrain
* 1-2" per hour snowfall rates north of I-90 and especially near
route 2 make for hazardous travel for the evening commute
* Mid level warm layer moving northward will result in Ptype
transitioning to a period of rain/ice south of I-90
* Narrow swath of sleet and freezing rain for a time into
northern CT, interior southern MA and far northwest RI
* Mainly rain along the I-95 corridor into RI that should transition
to a period of snow before ending toward daybreak
* Total snow accumulations of 5-10" in the highest terrain of
northern MA...2-5" in the lower elevations of western/central
MA...and mainly a dusting to 2" across RI and eastern MA
Details...
This afternoon into tonight...
Low pressure will be intensifying as it moves off the mid Atlantic
coast and tracks just inside the Benchmark this afternoon into this
evening. Thermal profiles are initially cold enough for mainly snow
northwest of the I-84/I-495 interchange inland from the coastal
front into mid afternoon. However...given the lack of cold high
pressure across eastern Canada and the mid level centers tracking
northwest of the Benchmark will allow warmer mid-level air to move
northward. Therefore...an initial burst of snow through early
afternoon will change to mainly rain south of I-90 by mid-late
afternoon. A few inches of snow may occur in this region before the
transition to rain across southwest/south central MA perhaps into
far northern CT. There remains some uncertainty how far north this
mid level warm layer will reach before stalling out...but we are
thinking this will mainly stay south of the route 2 corridor and
possibly not make it much further north than I-90. As the mid level
low/s close off and result in strong mid level frontogenesis...we
may see 1-2 per hour snowfall rates this afternoon into early
evening where Ptype remains snow north of I-90 and especially
towards route 2. This will result in significant impact to the
evening commute north of I90 and especially near route 2 corridor.
There also may be a narrow area of sleet and freezing rain on the
edge of the mid level warmth...but should be fairly narrow
swath. We did expand the Winter Weather Advisory into northern
CT to account for this risk. We also may see that narrow band of
sleet and freezing rain into interior parts of southern MA.
Meanwhile...areas south of I-90 as well as along the I-95
should see moderate to heavy rain for the late day commute.
As the mid level low/s shift east of the region...lingering moisture
with temps cooling aloft should allow for many locations to
transition to snow before things wind down before daybreak
Wednesday. A coating to an inch of snow will be possible onto the I-
95 corridor with perhaps 2" into the lower elevations of interior
eastern MA. Further northwest in the lower elevations of
western/central MA...total accumulations of 2-5" seem reasonable.
The highest snowfall amounts of 5-10" should be common across the
northern Worcester Hills/Berks and as well as areas north of route
2. All in all...no changes planned to any of the headlines
except for the expansion of the Winter Weather Advisory into
northern CT for a wintry mix of snow, sleet and freezing rain.
Lastly...gusty N winds will work into the region on the backside of
the system later this evening and overnight. Gusts of 20-30 mph are
expected overnight with some 35-40+ mph gusts possible across
the outer- Cape/Nantucket. Low temps by daybreak will be in the
20s across the interior...with lower to middle 30s along the
I-95 corridor and middle to upper 30s near the Cape and Islands.
So not expecting many issues with roads along and southeast of
I-95 corridor...but northwest of I-95 untreated roads will be
slippery for the Wed am commute despite the precipitation having
ended.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Key Messages...
* Mostly sunny/quiet weather Wed with highs ranging from the middle
30s in the high terrain to the upper 30s/lower 40s elsewhere
* Dry and chilly Wed night with lows in the upper teens and 20s
Details...
Wednesday...
A ridge of high pressure briefly builds to our southwest on
Wednesday. This will result in plenty of sunshine with winds
becoming rather light by later in the morning and afternoon.
Temperatures still below normal for early December...but not
bad with plenty of sunshine and light winds. Highs Wednesday
should range from the middle 30s in the high terrain and the
upper 30s to the lower 40s elsewhere.
Also...we did opt to issue a Coastal Flood Statement for the high
astro tide Wednesday morning along the eastern MA coast. Any
impacts should be very minor...but with building seas offshore
and a gusty N- NW winds some very minor coastal flooding/splash
over will be possible during the time of high tide with the best
chance south of Boston.
Wednesday night...
Dry and chilly weather is on tap for Wednesday night out ahead of an
arctic cold front. Low temperatures should mainly be in the upper
teens and 20s.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Key Messages:
* Scattered snow showers possible Thursday.
* Arctic airmass in place Thursday night-Saturday bringing well
below normal temperatures.
Details...
After a brief period of weak high pressure, a shortwave trough moves
through the region on Thursday accompanied by a strong cold front.
The wave is fairly moisture starved with precipitable water values
0.4-0.6". There should be a brief window with some mid-level
moisture advecting into the region. With the help of the
approaching front, this will provide lift for a few snow
showers during the day Thursday. Ensembles show low-moderate
probabilities for light QPF amounts. With marginal instability
present and approaching arctic front/airmass, global guidance
also hint at snow squall potential. Given limited moisture and
uncertainty in the details of the frontal passage, this will be
lower probability for now. A few convective showers/segments
that may be capable of a localized brief "burst" of higher snow
rates. Overall deterministic/ensemble guidance keeps totals
trace to light if anything given the localized nature of the
showers.
An arctic airmass will push in behind the front Thursday night.
850mb temperatures range -15 to -20C with mainly clear skies.
Despite breezy conditions (at least to start the night),
temperatures will likely plummet into the single digits for the
interior and teens along the coast. These are the coldest
temperatures of the season so far. As mentioned, winds may be
elevated to start the night which will bring wind chill values into
the negative single digits for the higher terrain and single digits
elsewhere. The arctic airmass remains in place for Friday support
high temperatures 10-15 degrees below normal. Highs struggle to
reach 30 degrees, with the exception of SE MA and the south coast in
the mid 30s.
Ensemble guidance shows a consensus for a transition to a more
active pattern heading into the weekend. There is a signal for a
coastal system to brush the region sometime late Friday-Saturday.
Details still less certain this far out, but this could bring
another round of precipitation to southern New England. Once timing
and track become more clear, we will get a better idea of precip
type (snow or mix/rain event).
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
18Z update...
Today...Moderate Confidence.
MVFR ceilings drop to IFR-LIFR as precip overspreads the region
this afternoon, 18-21z. Ptype rain for coastal terminals. SN
to start for BDL,BAF, BED, and ORH, with chance for RA to mix
in the afternoon 19z-21z. Lower confidence for precipitation
type due to uncertainty in location of rain-snow line. E-NE wind
5-15 kt. Minor accumulations for BDL, BAF, BED, and ORH. 2-6"
possible depending on where RA- SN line positions. Snowfall
rates less than 0.5"/hour for terminals.
Tonight...Moderate confidence.
Widespread IFR-LIFR improving to VFR late from west to east
after 06Z. Light SN for interior terminals in evening. Change
over to a period of light RA/SN or light SN possible along the
I-95 corridor, including BOS and PVD for a short period. Timing
of change over is lower confidence, but would be after 03Z.
Minor accum (Trace-0.5") possible at BOS. NE wind becoming N-NNW
with gusts to 25 kt developing, with 30-40 kt gusts possible
for Cape/Islands.
Wednesday...High Confidence.
VFR. NW winds with gusts up to 22 kts (up to 25 kts for
Cape/Islands) in the morning decreasing in the afternoon.
KBOS Terminal...Moderate confidence in TAF.
Changeover to -RASN or -SN possible Tuesday night. Exact timing
lower confidence, more likely between 03-07z.
KBDL Terminal...Moderate confidence in TAF. Lower confidence in
timing of ptype changes.
Outlook /Thursday through Saturday/...
Wednesday Night: VFR. Breezy.
Thursday: VFR. Windy with gusts up to 35 kt. Slight chance
SHRA, slight chance SHSN.
Thursday Night: VFR. Windy with gusts up to 35 kt.
Friday: VFR. Breezy.
Friday Night: VFR. Slight chance SN.
Saturday: VFR. Chance RA, slight chance SN.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Tonight...High confidence.
* Gale warnings tonight across our eastern waters
Rapidly intensifying low pressure system passes east of the
Benchmark this evening. This increase in pressure gradient results
in N wind gusts increasing to between 30 and 40 knots. Strongest of
those winds will be across our eastern waters where Gale Warnings
will continue. Across our western waters...strong small craft
advisories remain posted but a few brief gusts to 35 knots possible.
Wednesday and Wednesday night...
The low pressure system will already be east of the Canadian
Maritimes Wednesday morning. A weak ridge of high pressure will then
temporarily build to our southwest. This will allow winds to
diminish Wed and while seas will slowly drop off too...they will
remain elevated enough that small craft headlines will be needed
into early Wed evening. Winds/seas may both briefly drop below small
craft thresholds later Wed night...but SW wind gusts of 20-25 knots
will re-develop toward daybreak Thu ahead of our next cold front.
Outlook /Thursday through Saturday/...
Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft.
Thursday: Low risk for gale force winds with gusts up to 40 kt.
Areas of rough seas. Slight chance of rain showers.
Thursday Night: Moderate risk for gale force winds with gusts
up to 40 kt. Rough seas up to 10 ft.
Friday: Winds less than 25 kt. Seas locally approaching 5 ft.
Friday Night: Winds less than 25 kt. Slight chance of rain.
Saturday: Winds less than 25 kt. Chance of rain.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory until 7 AM EST Wednesday for CTZ002-
003.
MA...Winter Weather Advisory until 7 AM EST Wednesday for MAZ005-
006-010>012.
Winter Storm Warning until 7 AM EST Wednesday for MAZ002>004-
008-009-026.
RI...None.
MARINE...Gale Warning from 7 PM this evening to 7 AM EST Wednesday for
ANZ230.
Gale Warning from 7 PM this evening to 1 PM EST Wednesday for
ANZ231-232-250-251-254-255.
Small Craft Advisory until 7 PM EST Wednesday for ANZ233>235-
237.
Small Craft Advisory until 7 AM EST Wednesday for ANZ236.
Small Craft Advisory until 1 AM EST Thursday for ANZ256.
&&
$$
SYNOPSIS...Frank/Mensch
NEAR TERM...Frank
SHORT TERM...Frank
LONG TERM...Mensch
AVIATION...Frank/Dooley
MARINE...Frank/Mensch
FXUS61 KBOX 021859
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
159 PM EST Tue Dec 2 2025
.SYNOPSIS...
A winter storm will bring accumulating snow across interior
southern New England into tonight...particularly north of I-90
into the high terrain where significant snow accumulations are
expected. Mainly rain is expected across eastern MA and
RI...before a transition to snow occurs later tonight. All
precipitation should have come to an end by daybreak Wednesday.
An arctic front may be accompanied by a few snow showers or
squalls Thursday followed by very cold airmass Thursday night
and Friday. A coastal storm tracks well to the south Friday
night and Saturday but may bring a bit of light snow to the
region. Another cold front moves through Sunday followed by
another surge of very cold air Sunday night and Monday. Mainly
dry and cold conditions continue into Tuesday.
&&
.NEAR TERM /THROUGH TONIGHT/...
Key Messages...
* Winter Storm continues tonight across interior southern New
England especially north of I-90 and the high terrain
* 1-2" per hour snowfall rates north of I-90 and especially near
route 2 make for hazardous travel for the evening commute
* Mid level warm layer moving northward will result in Ptype
transitioning to a period of rain/ice south of I-90
* Narrow swath of sleet and freezing rain for a time into
northern CT, interior southern MA and far northwest RI
* Mainly rain along the I-95 corridor into RI that should transition
to a period of snow before ending toward daybreak
* Total snow accumulations of 5-10" in the highest terrain of
northern MA...2-5" in the lower elevations of western/central
MA...and mainly a dusting to 2" across RI and eastern MA
Details...
This afternoon into tonight...
Low pressure will be intensifying as it moves off the mid Atlantic
coast and tracks just inside the Benchmark this afternoon into this
evening. Thermal profiles are initially cold enough for mainly snow
northwest of the I-84/I-495 interchange inland from the coastal
front into mid afternoon. However...given the lack of cold high
pressure across eastern Canada and the mid level centers tracking
northwest of the Benchmark will allow warmer mid-level air to move
northward. Therefore...an initial burst of snow through early
afternoon will change to mainly rain south of I-90 by mid-late
afternoon. A few inches of snow may occur in this region before the
transition to rain across southwest/south central MA perhaps into
far northern CT. There remains some uncertainty how far north this
mid level warm layer will reach before stalling out...but we are
thinking this will mainly stay south of the route 2 corridor and
possibly not make it much further north than I-90. As the mid level
low/s close off and result in strong mid level frontogenesis...we
may see 1-2 per hour snowfall rates this afternoon into early
evening where Ptype remains snow north of I-90 and especially
towards route 2. This will result in significant impact to the
evening commute north of I90 and especially near route 2 corridor.
There also may be a narrow area of sleet and freezing rain on the
edge of the mid level warmth...but should be fairly narrow
swath. We did expand the Winter Weather Advisory into northern
CT to account for this risk. We also may see that narrow band of
sleet and freezing rain into interior parts of southern MA.
Meanwhile...areas south of I-90 as well as along the I-95
should see moderate to heavy rain for the late day commute.
As the mid level low/s shift east of the region...lingering moisture
with temps cooling aloft should allow for many locations to
transition to snow before things wind down before daybreak
Wednesday. A coating to an inch of snow will be possible onto the I-
95 corridor with perhaps 2" into the lower elevations of interior
eastern MA. Further northwest in the lower elevations of
western/central MA...total accumulations of 2-5" seem reasonable.
The highest snowfall amounts of 5-10" should be common across the
northern Worcester Hills/Berks and as well as areas north of route
2. All in all...no changes planned to any of the headlines
except for the expansion of the Winter Weather Advisory into
northern CT for a wintry mix of snow, sleet and freezing rain.
Lastly...gusty N winds will work into the region on the backside of
the system later this evening and overnight. Gusts of 20-30 mph are
expected overnight with some 35-40+ mph gusts possible across
the outer- Cape/Nantucket. Low temps by daybreak will be in the
20s across the interior...with lower to middle 30s along the
I-95 corridor and middle to upper 30s near the Cape and Islands.
So not expecting many issues with roads along and southeast of
I-95 corridor...but northwest of I-95 untreated roads will be
slippery for the Wed am commute despite the precipitation having
ended.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Key Messages...
* Mostly sunny/quiet weather Wed with highs ranging from the middle
30s in the high terrain to the upper 30s/lower 40s elsewhere
* Dry and chilly Wed night with lows in the upper teens and 20s
Details...
Wednesday...
A ridge of high pressure briefly builds to our southwest on
Wednesday. This will result in plenty of sunshine with winds
becoming rather light by later in the morning and afternoon.
Temperatures still below normal for early December...but not
bad with plenty of sunshine and light winds. Highs Wednesday
should range from the middle 30s in the high terrain and the
upper 30s to the lower 40s elsewhere.
Also...we did opt to issue a Coastal Flood Statement for the high
astro tide Wednesday morning along the eastern MA coast. Any
impacts should be very minor...but with building seas offshore
and a gusty N- NW winds some very minor coastal flooding/splash
over will be possible during the time of high tide with the best
chance south of Boston.
Wednesday night...
Dry and chilly weather is on tap for Wednesday night out ahead of an
arctic cold front. Low temperatures should mainly be in the upper
teens and 20s.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Key Messages:
* Scattered snow showers and localized squalls possible Thu
* Arctic airmass moves into SNE Thu night-Fri with very cold temps
* Coastal storm to the south may bring some light wintry precip Fri
night and Sat but bulk of precip expected to remain to the south.
Minimal impacts expected
* Another cold front will deliver a very cold airmass Sun night-Mon
Overview...
Overall -AO/-NAO pattern will persist through the extended period
keeping mean trough across the eastern CONUS with TPV over eastern
Canada. This will keep temps well below normal with a few surges of
arctic air. Overall, not looking at any significant precip events
through the period with northern stream dominant pattern and minimal
southern stream interaction.
Details...
An arctic front crosses the region Thu afternoon and evening and
will likely be accompanied by scattered snow showers. The snow
squall parameter is favorable Thu afternoon, especially across
northern MA as the front is moving so potential exists for a few
localized snow squalls. After the front moves through, gusty NW
winds during the afternoon and evening will usher in much colder air
with sharply falling temps. Winds diminish overnight as high pres
builds over New Eng with cold advection transitioning to radiational
cooling for the second half of the night. 925 mb temps bottom out
around -14 to -16C Thu night and recover to -8 to -10C on Fri. Lows
will drop into the single numbers interior and teens in the coastal
plain. High pres in control Fri with dry and cold weather and highs
mostly in the 20s, except lower 30s near the south coast.
Fast moving low amplitude shortwave moving off the mid Atlc coast
with coastal low tracking well to the south Fri night into Sat. Best
moisture and bulk of QPF remains to the south but can't rule out a
bit of light snow Fri night, especially south of the MA Pike, then
some light rain/snow showers possible during Sat. Ensemble guidance
indicates potential for a very light QPF event with minor accum less
than an inch possible with minimal impacts expected.
Another cold front will be moving through Sun with another surge of
arctic air Sun night into Mon with lows down into the single numbers
and teens again and highs Mon in the 20s to lower 30s. Mainly dry
weather Sun-Mon. Temps moderate some next Tue and it still looks dry
but confidence in sensible weather is low given considerable spread
in the guidance with timing, amplitude and location of approaching
shortwaves.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
18Z update...
Today...Moderate Confidence.
MVFR ceilings drop to IFR-LIFR as precip overspreads the region
this afternoon, 18-21z. Ptype rain for coastal terminals. SN
to start for BDL,BAF, BED, and ORH, with chance for RA to mix
in the afternoon 19z-21z. Lower confidence for precipitation
type due to uncertainty in location of rain-snow line. E-NE wind
5-15 kt. Minor accumulations for BDL, BAF, BED, and ORH. 2-6"
possible depending on where RA- SN line positions. Snowfall
rates less than 0.5"/hour for terminals.
Tonight...Moderate confidence.
Widespread IFR-LIFR improving to VFR late from west to east
after 06Z. Light SN for interior terminals in evening. Change
over to a period of light RA/SN or light SN possible along the
I-95 corridor, including BOS and PVD for a short period. Timing
of change over is lower confidence, but would be after 03Z.
Minor accum (Trace-0.5") possible at BOS. NE wind becoming N-NNW
with gusts to 25 kt developing, with 30-40 kt gusts possible
for Cape/Islands.
Wednesday...High Confidence.
VFR. NW winds with gusts up to 22 kts (up to 25 kts for
Cape/Islands) in the morning decreasing in the afternoon.
KBOS Terminal...Moderate confidence in TAF.
Changeover to -RASN or -SN possible Tuesday night. Exact timing
lower confidence, more likely between 03-07z.
KBDL Terminal...Moderate confidence in TAF. Lower confidence in
timing of ptype changes.
Outlook /Thursday through Sunday/...
Thursday: VFR. Windy with gusts up to 35 kt. Slight chance
SHSN.
Thursday Night: VFR. Windy with gusts up to 35 kt.
Friday: VFR. Breezy.
Friday Night: VFR. Slight chance FZRA, slight chance SN.
Saturday: VFR. Chance RA, slight chance SN.
Saturday Night through Sunday: VFR.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Tonight...High confidence.
* Gale warnings tonight across our eastern waters
Rapidly intensifying low pressure system passes east of the
Benchmark this evening. This increase in pressure gradient results
in N wind gusts increasing to between 30 and 40 knots. Strongest of
those winds will be across our eastern waters where Gale Warnings
will continue. Across our western waters...strong small craft
advisories remain posted but a few brief gusts to 35 knots possible.
Wednesday and Wednesday night...
The low pressure system will already be east of the Canadian
Maritimes Wednesday morning. A weak ridge of high pressure will then
temporarily build to our southwest. This will allow winds to
diminish Wed and while seas will slowly drop off too...they will
remain elevated enough that small craft headlines will be needed
into early Wed evening. Winds/seas may both briefly drop below small
craft thresholds later Wed night...but SW wind gusts of 20-25 knots
will re-develop toward daybreak Thu ahead of our next cold front.
Outlook /Thursday through Sunday/...
Thursday: Low risk for gale force winds with gusts up to 40 kt.
Areas of rough seas. Slight chance of rain showers.
Thursday Night: Moderate risk for gale force winds with gusts
up to 40 kt. Rough seas up to 10 ft.
Friday: Winds less than 25 kt. Seas locally approaching 5 ft.
Friday Night: Winds less than 25 kt. Chance of rain, chance of
snow.
Saturday: Winds less than 25 kt. Chance of rain.
Saturday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain.
Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory until 7 AM EST Wednesday for CTZ002-
003.
MA...Winter Weather Advisory until 7 AM EST Wednesday for MAZ005-
006-010>012.
Winter Storm Warning until 7 AM EST Wednesday for MAZ002>004-
008-009-026.
RI...None.
MARINE...Gale Warning from 7 PM this evening to 7 AM EST Wednesday for
ANZ230.
Gale Warning from 7 PM this evening to 1 PM EST Wednesday for
ANZ231-232-250-251-254-255.
Small Craft Advisory until 7 PM EST Wednesday for ANZ233>235-
237.
Small Craft Advisory until 7 AM EST Wednesday for ANZ236.
Small Craft Advisory until 1 AM EST Thursday for ANZ256.
&&
$$
SYNOPSIS...KJC/Frank
NEAR TERM...Frank
SHORT TERM...Frank
LONG TERM...KJC
AVIATION...Frank/Dooley
MARINE...KJC/Frank
