textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes.

KEY MESSAGES

- Scattered showers exiting by late afternoon. Becoming windy into this evening, then clearing and cold with diminishing wind overnight.

- Dry conditions with less wind Wednesday and Wednesday night. Below normal temps continue.

- Warming trend to temperatures Thursday and Friday. Still very dry Thursday which could lead to fire weather concerns as southerly winds increase.

- Dry weather generally prevails late this week into early next week. Cooler temperatures for the weekend, but growing confidence on a spell of above normal temperatures for early next week.

DISCUSSION

KEY MESSAGE 1...Scattered showers exiting by late afternoon. Becoming windy into this evening, then clearing and cold with diminishing wind overnight.

Mid level trough passage and cold pool move through this afternoon. Scattered showers associated with this trough are moving through SNE this afternoon and can't rule out some graupel given the cold air aloft and steep lapse rates. As the cold front moves through this afternoon winds will shift to NW with 25-35 mph gusts into early evening. A few 40 mph gusts are possible over higher terrain.

The trough exits tonight followed by subsidence and high pres building in from the west. Expect clearing skies with diminishing wind overnight as the gradient slackens. It will be rather cold for this time of year with lows dropping into the 20s and some teens in the colder spots in western MA.

KEY MESSAGE 2...Dry conditions with less wind Wednesday and Wednesday night. Below normal temps continue.

Strong high pres builds across New Eng Wed before shifting to the east Wed night. Despite abundant sunshine Wed, shallow mixing and light winds will result in a cool day with highs in the 40s to perhaps low 50s in the lower CT valley. Developing sea-breezes will likely hold temps near 40F along the eastern MA coast and Cape/Islands.

Mainly clear skies and light winds Wed night as high pres slowly drifts offshore, but ridging hangs back across New Eng. Another cold night with lows in the 20s.

KEY MESSAGE 3...Warming trend to temperatures Thursday and Friday. Still very dry Thursday which could lead to fire weather concerns as southerly winds increase.

Steady warming trend continues Thursday and Friday with a ridge of high pressure anchored to our southern coastline. Mostly clear to partly sunny conditions should dominate both days, with south to southwest winds around 10 mph, up to 15 mph in western portions of Southern New England. Dewpoints are still not likely to have recovered enough by Thursday, which will bring relative humidities given favorable mixing down into the 20-25 percent range; thus, possible fire weather concerns on Thursday, although the winds/gusts are not particularly strong. Warmer day on Friday will be met with more moisture too, with highs Friday into the 60s. All in all though, both days are rather pleasant.

KEY MESSAGE 4...Dry weather generally prevails late this week into early next week. Cooler temperatures for the weekend, but growing confidence on a spell of above normal temperatures for early next week.

Latest guidance now indicates a moisture-starved cold frontal passage now about 6-12 hours sooner, instead moving through Saturday morning. Other than some cloud cover, chances for rain with this frontal passage look scant. Passage of the cold front will bring arrival of cooler temperatures later Saturday with a period of onshore flow/marine-influenced air for Sunday.

Only looks to be a brief cooldown though, as we enter into a stretch of very mild weather for at least Monday and Tuesday. 925 mb temps warm into the upper teens to around +20C, which would support highs in the mid 70s factoring in southwesterly flow downsloping.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Forecaster Confidence Levels...

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

18z TAF update:

Through Wednesday night...High confidence.

Areas of MVFR conditions with scattered showers until 20-21z, otherwise VFR through the period. NW gusts to 25-30 kt with brief 35 kt possible through early evening, then diminishing wind late tonight. Light wind Wed & Wed night with sea-breezes developing by late Wed morning.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Thursday through Sunday/...

Thursday through Thursday Night: VFR. Breezy.

Friday: VFR.

Friday Night: VFR. Chance SHRA.

Saturday through Sunday: VFR.

MARINE

Forecaster Confidence Levels...

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

Tonight through Wednesday night...High confidence.

SCA in effect for all waters through tonight.

Increasing NW winds with gusts to 25-30 kt through much of tonight, diminishing below 20 kt late tonight and Wed morning. High pres builds over the waters Wed afternoon into Wed night with light winds and seas, generally easterly wind 5-15 kt Wed afternoon becoming SE-S Wed night.

Outlook /Thursday through Sunday/...

Thursday through Thursday Night: Winds less than 25 kt.

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

Friday Night: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers.

Saturday: Winds less than 25 kt. Local rough seas.

Saturday Night: Winds less than 25 kt. Seas up to 5 ft.

Sunday: 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 from 5 PM this afternoon to 5 AM EDT Wednesday for ANZ230. Small Craft Advisory from 5 PM this afternoon to 8 AM EDT Wednesday for ANZ231-250-251-254. Small Craft Advisory until 8 AM EDT Wednesday for ANZ232-255- 256. Small Craft Advisory until 5 AM EDT Wednesday for ANZ233>235- 237. Small Craft Advisory until 2 AM EDT Wednesday for ANZ236.