textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes. Gusty winds will quickly diminish this morning.

KEY MESSAGES

- Quiet conditions today before wind gusts resume tonight

- Turning colder and blustery late Sunday into Monday

- Light snow accumulations possible Tue

- Warming trend for the end of the week

DISCUSSION

KEY MESSAGE 1...Quiet conditions today before wind gusts resume tonight

We'll see a brief respite from the high winds during the day today as a high pressure system pushes through. Another cold front extending from a Canadian low moves through southern New England by Saturday night, bringing another round of gusty winds 25-35 mph to the region.

KEY MESSAGE 2...Turning colder and blustery late Sun into Sun night

Strong cold front will be moving through SNE from late morning through the afternoon. Moisture is limited and none of the guidance is indicating any precip so expect a mostly dry fropa. The front will be preceded by a period of gusty SW winds late tonight into Sun morning, mainly along the immediate south coast and Cape/Islands. We have a modest low level jet which will be moving offshore but soundings do show a shallow mixed layer enough for some gusts to 25- 35 mph, strongest over the Islands. Behind the front, strong cold advection and deepening boundary layer will support similar 25-35 mph gusts late Sun into Sun night, with the strongest winds over the higher elevations. Winds gradually diminish through Monday. Seasonable temps Sun ahead of the front then falling temps behind the front Sun afternoon, especially interior and turning much colder Sun night as 850 mb temps bottom out at -12 to -15C. Wind chills by Mon morning will drop to 5-10F and near zero in the Berkshires. Temps will be several degrees below normal Mon with highs upper 20s and lower 30s and plentiful sunshine in very dry airmass.

KEY MESSAGE 3...Light snow accumulations possible Tue

A fast moving shortwave in NW flow aloft with warm front approaching from the SW and decent isentropic lift will bring a period of precip to SNE. Still some uncertainty with timing and when precip begins but highest confidence is during Tue. Column is cold enough snow as moisture moves into the region so expect a period of light snow for all SNE. The uncertainty is with the extent of boundary layer warming and any transition to rain. Best chance of a changeover will be near the south coast but this is not looking like a significant QPF event. Global ensembles do show moderate to high probs (>70%) for 1" or greater across the interior with lower probs near the coast, while there are low probs (<20%) for 3". So preliminary estimates are for an inch or 2 accum with best chance in the interior.

KEY MESSAGE 4...Warming trend for the end of the week

Amplifying northern stream trough moves to the east Wed then broad ridging develops across the central and eastern CONUS which will result in a warming trend through the end of the week. Temps will be near or a bit below normal Wed then warming above normal Thu and especially Fri when temps could make a run at 50F. Weak shortwave around Christmas Day may bring some shower activity but better chance will be Fri as more robust shortwave approaches. Any precip during the end of the week will be mostly rain in warming environment.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

Forecaster Confidence Levels...

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

Today through Saturday...High Confidence in trends

VFR through the period. Gusty WNW winds with gusts 30-40 kt diminishing this morning, then shifting to SW this afternoon. SW gusts 25-30 kts resume late tonight into Sunday morning, mainly along the immediate coast and Islands and higher terrain.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Sunday through Wednesday/...

Sunday: VFR. Windy with areas of gusts up to 30 kt.

Sunday Night: VFR. Windy with gusts up to 30 kt.

Monday: VFR. Breezy.

Monday Night: VFR. Slight chance SN.

Tuesday: MVFR/IFR conditions possible. Breezy. SN likely, chance RA.

Tuesday Night: Mainly VFR, with local IFR possible. Breezy.

Wednesday: VFR. Breezy.

MARINE

Forecaster Confidence Levels...

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

Through Tonight...High Confidence.

Winds diminish this morning and drop below 20 kt this afternoon with subsiding seas. Another pulse of 25-35 kt SW gusts develop tonight ahead of a cold front. Another round of gale warnings will likely be needed for some of the waters.

Outlook /Sunday through Wednesday/...

Sunday: Strong winds with gusts up to 35 kt. Rough seas up to 11 ft.

Sunday Night: Strong winds with gusts up to 30 kt. Rough seas up to 10 ft.

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

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

Tuesday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Rain likely. Local visibility 1 to 3 nm.

Tuesday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Slight chance of rain.

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

BOX WATCHES/WARNINGS/ADVISORIES

CT...Wind Advisory until 7 AM EST this morning for CTZ002>004. MA...Wind Advisory until 7 AM EST this morning for MAZ002>024-026. RI...Wind Advisory until 7 AM EST this morning for RIZ001>008. MARINE...Gale Warning until 7 AM EST this morning for ANZ230. Gale Warning until 9 AM EST this morning for ANZ231>235-237- 250-251-254>256. Gale Warning until 5 AM EST early this morning for ANZ236.