textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes were made to the forecast through Tuesday.

KEY MESSAGES

- Lingering snow showers end later this afternoon giving way to very cold temperatures tonight through Tuesday morning.

- A wintry mix of precipitation is possible Tuesday into Tuesday night.

- Remaining unsettled beyond Wednesday with temperatures trending above normal.

DISCUSSION

KEY MESSAGE 1...Lingering snow showers end later this afternoon giving way to very cold temperatures tonight through Tuesday morning.

Line of light to moderate snow showers quickly exits the coast later this afternoon, weakening as it does so. Should see skies quickly clear with increasing northwest winds and a sharp drop in temperatures this evening. The Arctic front ushers in another round of very cold temperatures starting tonight and lasting into Tuesday morning. 850 mb temps bottom out at -16C Monday morning, with the 510 thickness line nearly reaching southern New England. This will result in low temperatures Monday morning in the low single digits, possibly below zero in NW MA. With a little leftover wind from the arctic front overnight, the wind chill index will be below zero Monday morning, possibly approaching -10 across the interior.

Despite the higher March sun angle, high temperatures will stay below freezing on Monday with a wind chill index in the lower 20s. 850mb temperatures begin to rise overnight Monday. However, strong radiational cooling under calm winds and clear skies will allow low temperatures to bottom out in the low teens to high single digits Tuesday morning.

KEY MESSAGE 2...A wintry mix of precipitation is possible Tuesday into Tuesday night.

Still expecting a wintry mix to develop Tuesday into Tuesday night. Temperatures should initially remain low enough where some light snowfall is possible across the higher terrain of CT and MA. Not expecting this will last long as temperatures continue to rise. Expecting plain rainfall across most of southern New England by Tuesday evening. Still thinking the cold front associated with the low pressure passing by our region should be off the coast by Wednesday morning. Thus, decreasing precipitation chances from NW to SE late Tuesday night. Should be dry across all of southern New England by mid morning Wednesday.

Thinking light snowfall accumulations of generally less than 1 inch. Kept the possibility of freezing rain out of the forecast at this time, largely because it would be brief and the timing remains uncertain. Will get a better handle on this as we get more into the range of the high resolution guidance. A more substantial period of freezing rain would only cut into snowfall accumulations even more. However, winter weather headlines may be needed for the icing potential.

KEY MESSAGE 3...Remaining unsettled beyond Wednesday with temperatures trending above normal.

The active weather pattern continues through the end of this upcoming work week as the zonal jet stream and stalled frontal boundary send several weak waves near or through southern New England. Temperatures starting Wednesday are expected to rise well above normal, with highs approaching the 50s and overnight lows even staying near or above freezing. This will help keep any precipitation that falls during this time as rain.

Still thinking our region gets caught between a pair of fronts Thursday into Friday, making this a more specific time with a greater risk for rainfall. Otherwise, it appears that we'll have at least a chance of off-and-on precipitation through next weekend.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

Forecaster Confidence Levels...

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

Through 00z Monday...High Confidence.

VFR behind the snow with gusty NW winds around 20 knots.

Tonight through Monday...High Confidence.

Conditions return to VFR after the -SN moves offshore. NW-ly winds 5-10 knots.

KBOS Terminal...Moderate confidence in TAF.

VFR. NW-ly winds 5-10 knots.

KBDL Terminal...Moderate confidence in TAF.

VFR. NW-ly winds 5-10 knots.

Outlook /Monday Night through Friday/...

Monday Night: VFR.

Tuesday: Mainly VFR, with local IFR possible. RA likely, chance SN.

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

Wednesday: VFR. Slight chance RA.

Wednesday Night through Thursday: Mainly VFR, with areas IFR possible. Chance RA.

Thursday Night: MVFR/IFR conditions possible. RA likely.

Friday: MVFR/IFR conditions possible. Chance RA.

MARINE

Forecaster Confidence Levels...

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

Through Monday...High confidence.

Northerly winds of 25-30 knots tonight into Monday morning, with seas building to 5 feet across the outer waters where SCA's continue through Monday afternoon. Widespread light to moderate freezing spray across the inner waters beginning later tonight and lingering through late Monday morning. Winds, seas, and spray subside later Monday afternoon as high pressure builds overhead.

Outlook /Monday Night through Friday/...

Monday Night: Winds less than 25 kt.

Tuesday: Winds less than 25 kt. Seas locally approaching 5 ft. Rain likely.

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

Wednesday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain.

Wednesday Night through Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain.

Thursday Night through Friday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Freezing Spray Advisory from 1 AM to 10 AM EST Monday for ANZ231>235-237-251-255-256. Small Craft Advisory from 9 PM this evening to 1 PM EST Monday for ANZ250-254>256.