textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes.

KEY MESSAGES

- Mostly sunny, cool and blustery Monday. Could see a few rain/snow showers Monday night into Tuesday.

- Later in the week looks to remain mostly dry with temperatures on the rise.

DISCUSSION

KEY MESSAGE 1...Mostly sunny, cool and blustery Monday. Could see a few rain/snow showers Monday night into Tuesday.

A upper-level trough moving through the Great Lakes and into New England will bring a cold pool aloft, with 850mb temperatures around -5C and 500mb temperatures below -30C. A shortwave then moves through, which would help support some light snow showers possibly developing and mixing in with rain showers, especially over the higher elevation areas. Guidance has trended towards a later start, perhaps after midnight/early Tuesday morning instead of Monday... though we can't rule out a stray shower developing today in the higher elevations. Surface temperatures will likely hover near or possibly just below freezing Monday night into Tuesday morning, but they're expected to make a fast recovery later Tuesday morning... into the low to mid 40s. A secondary shortwave moves through later Tuesday and may allow showers to linger through part of the day, but not expecting much in the way of rain totals.

KEY MESSAGE 2...Later in the week looks to remain mostly dry with temperatures on the rise.

Drier conditions and southwesterly flow are expected to return to southern New England as a large high pressure system moves into the Mid-Atlantic region Wednesday. Temperatures will improve throughout the second half of the week as the upper level trough moves off to the east and a warmer airmass advects into the region. Expecting highs to rebound into the 50s by Thursday and further improve into the 60s by Friday. However, some uncertainty remains towards the end of the week as some ensemble guidance hints at another backdoor front moving in Saturday night into Sunday. High pressure moving east from just to our north could encourage onshore flow early Sunday morning and possibly continuing through the day before it shifts further offshore and winds return to SW.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Forecaster Confidence Levels...

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

Today: High confidence.

VFR. NW winds increasing through this morning to 12-17 kt and gusts 25-35 kt, with the highest gusts across the higher terrain.

Tonight: High confidence overall, though moderate on possible precip chances.

Disturbance aloft moves through Southern New England tonight, which will bring at least SCT-OVC cloud deck, mainly VFR ceilings. Less confident on if any precip with sweep through, but potential exists for brief periods of MVFR visby under light SHSN. NW winds decrease to 8-12 kt with gusts in lower 20 knot range.

Tuesday: Moderate confidence.

Could see some -SHSN spreading east across SNE early Tues AM, but not very confident on exact timing or if anything will manifest at BOS. Generally W winds 10-15 knots with occasional gusts 20-25 knots possible.

KBOS Terminal...High Confidence in TAF.

KBDL Terminal...High Confidence in TAF.

Outlook /Tuesday Night through Friday/...

Tuesday Night: VFR. Breezy.

Wednesday through Wednesday Night: VFR.

Thursday through Friday: VFR. Breezy.

MARINE

Forecaster Confidence Levels...

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

High confidence.

SCAs continue through most of today with seas at or above 5 ft across most waters and SW winds gusting 25-30 kts. Guidance has lowered on wind speeds tonight into Tuesday morning, so elected to allow SCAs to expire later this afternoon.

Seas remain below 5 ft through Tuesday, but some northwesterly wind gusts may approach SCA levels Tuesday evening across the southern waters ahead of an approaching high pressure system.

Outlook /Tuesday Night through Friday/...

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

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

Wednesday Night through Thursday Night: Winds less than 25 kt.

Friday: 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 until 2 PM EDT this afternoon for ANZ250. Small Craft Advisory until 8 PM EDT this evening for ANZ254>256.