textproduct: Boston / Norton

SYNOPSIS

Gusty winds expected today with scattered light snow showers possible for western MA and pockets of flurries for the interior. Still colder for Saturday but not as windy compared to Friday. Low pressure passes to our north and west Sunday afternoon and night bringing a period of rain with it. Cooling down again for Monday as a cold front passes through. Monitoring possible storminess around Tuesday which could bring snow and/or rain to Southern New England.

NEAR TERM /THROUGH TONIGHT/

Key Messages...

* Gusty and cold.

* Scattered show showers/flurries possible over western/central MA.

By 9-10am winds should pick up in earnest as the sun/warming sfc temps together with mid level cold advection lead to a well mixed boundary layer, mixing down stronger winds than we saw yesterday. Model sounding indicate gusts of 40+kts at the top of the boundary layer...thinking we should realize gusts of 30-40 mph at the surface. The best chance for stronger gusts to 45 mph remains in the higher terrain of the Berkshires. Expect a colder day today thanks to continued cold NW flow in the low/mid levels; the winds will make it feel more like the 20s to low 30s. This trajectory also lines up to pull some moisture from the Great Lakes in the western periphery of SNE in the form of light snow shower/flurries. This may make it as far as central MA but isn't expected to lead to any appreciable accumulation. Tonight winds likely won't diminish much after sunset, but continue through around midnight before lessening more significantly.

SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/

Key Messages...

* Still cold Saturday with less breezy winds.

Saturday high pressure continues to push overhead lessening the pressure gradient (and resulting winds) while still directing cool NW flow into the region. Thus, expecting winds to be breezy but not as strong as Friday, on the order of 20-30 mph gusts. Highs will be similar to Friday, in the upper 30s to low 40s.

LONG TERM /SUNDAY THROUGH FRIDAY/

Key Messages...

* Less windy on Saturday.

* Temps warm Sunday before dropping again by Monday.

* Quick hitting rain Sunday/Sunday night.

* Possibility of a wintry storm Tuesday, favoring interior/high elevations for snow with rain elsewhere. Still far too soon to nail down these details.

A decent warm-up is in store for Sunday ahead of another round of rain. A warm front lifts north bringing first increasing cloudcover followed by isentropically forced rainfall overspreading from west to east Sunday afternoon into the evening. The parent low tracks well north of the region keeping temperatures solidly warm enough to fall as all rain (highs in the 40s and 50s). It also moves rather quickly from the Great Lakes into Quebec, dragging the cold front through and shutting off precipitation overnight Sunday. Most locations pick up less than a quarter inch of rain followed by a dry, colder, and breezy Monday as high pressure briefly passes overhead.

The potential first real storm system of the winter season continues to be possible on Tuesday. While important specifics remain unknown, global guidance is in good agreement that we will have a storm system in the vicinity around Tuesday. This comes as a mid level trough digging into the eastern U.S. induces a deepening surface low that should lift from the Mid-Atlantic through/past New England. Whether the eventual track is offshore (favoring more snow in SNE) or directly over us (favoring northern New England snow) the latest deterministic and ensemble guidance has not changed much in indicating an interior/high elevation snow event and a rain or snow to rain scenario for the lower elevations including the I-95 corridor. If the low track continues to shift further north it becomes less and less of a concern. For now, keeping in mind the still warm ocean temps (40s and 50s) and lack of a prolonged sub freezing antecedent airmass, continuing to think positive-snow-depth output is a more realistic look at any snow potential. We will learn more over the coming days. Regardless, rising heights and quieter weather look to follow Wed into Thu.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

Forecaster Confidence Levels...

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

18Z Update...

This Afternoon...High Confidence.

VFR. W winds 15-25 kts with gusts 25-30 kts. Can't rule out an isolated gust up to 35 kts, mainly for the the higher terrain and Cape/Islands. Periods of BKN decks this afternoon 4000-8000 ft. Widely scattered flurries/light snow showers through 00Z. Low probability of brief minor reductions in visibility in any passing showers.

Friday night...High Confidence.

VFR. Wind gradually trend downward overnight, but remain gusty. W winds 10-15 kts gusting 20-30 kts, decreasing further after 06Z.

Saturday...High Confidence.

VFR. W wind becoming more NW. Winds 8-12 kts gusting to 20-25 kts.

KBOS Terminal...High confidence in trends. Moderate for -SN chances.

VFR most likely. Widely scattered flurries/snow showers move across Massachusetts this afternoon with potential for some to pass near/at the terminal. Confidence is lower due to the scattered nature of the showers. Reductions in visibility not likely. Worst case scenario, a brief minor reduction to 6-8SM. Shower chances should end by 00z.

KBDL Terminal...High confidence in TAF.

Outlook /Sunday through Wednesday/...

Sunday: MVFR/IFR conditions possible. Breezy. RA likely.

Sunday Night: Mainly VFR, with areas MVFR possible. Windy with local gusts up to 30 kt. RA likely.

Monday: VFR. Breezy.

Monday Night: VFR.

Tuesday: Mainly VFR, with areas IFR possible. Chance RA, slight chance SN.

Tuesday Night: Mainly VFR, with areas IFR possible. Breezy. Chance SN, chance RA.

Wednesday: Breezy.

MARINE

Forecaster Confidence Levels...

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

Today through Saturday... High confidence.

* Gale Warning for Friday through early Saturday across all waters.

Higher winds expected on Friday. Winds expected to increased after 15z. West winds 25-35 kts with gusts at 40 kts. Greatest probability of hitting Gale criteria more consistently will be the southern waters Friday late morning and afternoon. Winds and seas slowly decrease overnight Friday into early Saturday. Gale Warning will be in effect for all marine zones starting 12z Friday, through 12Z Saturday.

Seas increase to 6-10 ft on Friday, diminishing by later Saturday. Outlook /Sunday through Wednesday/...

Sunday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Rain likely.

Sunday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Rain.

Monday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Slight chance of rain.

Monday Night: Winds less than 25 kt.

Tuesday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain. Local visibility 1 to 3 nm.

Tuesday Night: Moderate risk for Small Craft Advisory winds with local gusts up to 30 kt. Rough seas up to 12 ft. Chance of rain. Local visibility 1 to 3 nm.

Wednesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Rough seas up to 9 ft. Slight chance of rain.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Gale Warning until 7 PM EST this evening for ANZ230-236. Gale Warning until 7 AM EST Saturday for ANZ231>235-237-250- 251-254>256.