textproduct: Boston / Norton

WHAT HAS CHANGED

No major changes to the forecast.

KEY MESSAGES

- Snow gradually exits the region early this morning. Mainly dry for rest of today and Thursday with the exception of a few light snow showers.

- Quiet pattern overall with periods of nuisance light snow and minimal impacts. Temperatures moderate to near seasonable norms. Attention turns to the late weekend for a potential coastal storm, but forecast confidence remains low due track uncertainty.

DISCUSSION

KEY MESSAGE 1...Snow gradually exits the region early this morning. Mainly dry for rest of today and Thursday with the exception of a few light snow showers.

The clipper system is expected to exit the region early this morning, ending the bulk of the snow/wintry precipitation generally from west to east between 1-7 AM. Dry air moves into the upper and mid-levels (DZG) tapering off snow rates while the system shifts offshore. Still can't rule out patchy freezing drizzle/snizzle for a brief period early this morning if moisture ends up lingering in the low levels.

Mainly dry conditions expected for the rest of today. Drier air and cold advection will allow for mixing of gusty NW winds to the surface today with gusts 20-30 mph. We'll tap into some mid-level moisture off the Great Lakes toward the afternoon which will bring in cloud cover. NW winds may favor some upslope for the Berkshires for light snow showers. A few showers may make it over on the east side with a coating at most.

Thursday AM, an inverted trough tied to a departed surface low shifts south across the southern New England coastal waters. This will provide a brief period of ascent to support light snow showers mainly for the outer Cape, but potentially brushing Cape Ann. Model guidance continues to show more of an offshore brush with higher probabilities for a light accumulation of snow confined to the outer Cape. Model soundings show a period of modest lift/moisture within the DGZ. Enough to support a light accumulation (< 1") of snow Thursday morning.

KEY MESSAGE 2...Quiet pattern overall with periods of nuisance light snow and minimal impacts. Temperatures moderate to near seasonable norms. Attention turns to the late weekend for a potential coastal storm, but forecast confidence remains low due track uncertainty.

Surface high pressure builds across the eastern CONUS into the end of the week, maintaining seasonable temperatures. An upper-level low and northern-stream shortwave cross New England Friday night into early Saturday, bringing a low (<30%) probability of snow showers to southern New England. This remains a moisture-starved system with PWATs below climatological normals, though minor accumulations are possible across the higher terrain of northern and western Massachusetts. Tranquil and seasonable conditions are expected for the upcoming weekend as high pressure remains dominant.

Looking ahead, guidance continues to signal for a robust mid-level shortwave to cross the Texas panhandle with development of an area of low pressure across the Red River Basin by Saturday afternoon. Where this feature moves toward is uncertain. The last couple of days, the models have suggested it moves off the Carolina coast, strengthens, and possibly becomes a significant coastal storm for our region. As mentioned last night, predictability remains low at this range. 00z ensemble guidance depicts a wide variety of solutions, GFS ENS would have this surface low move towards the Gulf Coast. ECMWF ENS depicts a large clustering off the Carolina coast, many of the members are out to sea and south of the bench mark. Though a small number of the members pass very close to the bench mark. Similar, but not as robust is the CMC ENS. UKMET has backed off, with a shift towards an track out to sea. And for good measure, the deterministic AI runs of the GFS and ECMWF have a solution of out to sea. Opt'd for low-end POPs Sunday night into Monday due to uncertainties. At this time, confidence in any impacts remains low, though the system bears monitoring.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

Forecaster Confidence Levels...

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

Today...High confidence.

Improving ceilings through the morning with most terminals becoming VFR by 12Z while the Cape/Islands may have lingering MVFR through 14Z. NW winds with gusts developing after 14Z. Gusts up to 20-25 kts. Can't rule out the low chance for an isolated flurry/light snow shower across western MA/CT mid afternoon through the evening.

Tonight...High confidence.

VFR. Breezy NW winds with gusts up to 20 kt.

Thursday...High confidence.

VFR. Breezy NW winds with gusts 20-25 kts. Few snow showers possible over outer Cape Cod in the morning.

KBOS Terminal...High Confidence.

Improving ceilings to VFR toward 12Z. Gusty wind develops after 15z.

KBDL Terminal...High Confidence.

Outlook /Thursday Night through Sunday/...

Thursday Night: VFR. Breezy.

Friday: VFR.

Friday Night: VFR. Slight chance SN.

Saturday: VFR. Breezy.

Saturday Night through Sunday: VFR.

MARINE

Forecaster Confidence Levels...

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

Wednesday through Thursday...High Confidence.

* Small Craft Advisory for outer ocean waters and all waters south of Rhode Island

Low pressure system exiting east, southwest winds increase and veer to the west-northwest at 15-20 kt with gusts up to 30 kt. Seas build this afternoon to 4-7 ft on the southern outer waters and 2-5 ft on the eastern outer waters. Overnight, winds northwest 15-20 kt with gusts up to 30 kt. Seas overnight are 4-7 ft on the southern outer waters and building to 3-6 ft on the eastern outer waters. Winds and seas begin to subside Thursday, falling below advisory criteria late afternoon, as high pressure builds in from the west.

Outlook /Thursday Night through Sunday/...

Thursday Night: Winds less than 25 kt. Seas up to 5 ft. Freezing spray.

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

Friday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of snow.

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

Sunday: Winds less than 25 kt.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 10 PM this evening to 3 PM EST Thursday for ANZ235-237. Small Craft Advisory from 6 PM this evening to 7 PM EST Thursday for ANZ250. Small Craft Advisory until 7 PM EST Thursday for ANZ254>256.