textproduct: Boston / Norton

WHAT HAS CHANGED

No major changes since Wednesday morning update.

KEY MESSAGES

- Mild conditions today will be followed by a soaking rain tonight into Friday. Cooler, but still near normal Friday.

- Cold and windy start to the weekend with a warm up expected Sunday and the start of the work week. Watching the chance for unsettled weather through at least mid week.

DISCUSSION

KEY MESSAGE 1...Mild conditions today will be followed by a soaking rain tonight into Friday. Cooler, but still near normal Friday.

A band of rainfall moving across southern New England this morning was not resulting in much accumulation at the ground, despite some higher reflectivity. Expecting this band to be well over the ocean by around daybreak, leaving dry conditions for this morning. Increasing southwest winds will push warmer air into our region. Any sunshine we get this morning should be effective in boosting temperatures above normal, with many locations in the 60s away from the immediate south coast. Still stuck int he 50s there due to the onshore flow. Depending on how much sunshine we get this morning, a few spots in the CT River valley could even push 70 degrees for a high temperature.

More clouds and rain arrive along and ahead of a cold front late today across western MA, but especially tonight for most of southern New England. Still thinking a forecast of 0.25-0.50 inch of rainfall is most likely when all is done later Friday morning. Drier and colder weather overspreads our region Friday as well. This cold advection appears to be strong enough to hold temperatures nearly steady during the day. While colder than today, high temperatures should still be near normal for late March.

KEY MESSAGE 2...Cold and windy start to the weekend with a warm up expected Sunday and the start of the work week. Watching the chance for unsettled weather through at least mid week.

By Saturday the of the trough moves over New England with 500 mb heights falling to 520dm. We won't see too much in the way of improving temperatures as 850mb temps remain well below -10C, or about 15-20 below average! Thus, expect highs to struggle into the upper 30s to lower 40s on Saturday and Sunday with NW flow and continued cold advection aloft. Gusty NW winds will make it feel closer to the teens and 20s across the region, especially on Saturday. Expect warmer conditions to arrive Monday as high pressure shifts offshore and establishes a southwesterly return flow. Highs likely climb into the lower to mid 50s Monday afternoon.

Focus then shifts to another frontal boundary that arrives later Monday into Tuesday. Guidance initially shows a cold front that moves SE before slowing and transitioning to more of a stationary front somewhere over New England. This boundary could act as a focus for numerous waves of unsettled weather starting later Monday and for perhaps the first half of the week. Ensembles have ample PWATs (150-200 percent of normal) so, no issues with available moisture. Uncertainty will be driven primarily by the location of the frontal boundary and the eventual track/intensity of shortwaves originating from the Pacific Northwest and racing east on an increasingly zonal upper flow.

AVIATION /12Z THURSDAY THROUGH MONDAY/

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

Today...High confidence.

VFR conditions dominate outside perhaps some brief marginal MVFR cigs under -RA during the early-mid morning hours. SW wind gusts of 20-30 kt develop. Generally dry weather, but a few spot showers possible mainly early in the morning and perhaps later in the day near the NH border. Strong LLWS possible over the south coast with 40-50 kt of shear to 2000 feet.

Tonight...Moderate confidence.

Conditions deteriorate to MVFR/IFR, possibly even LIFR, tonight with -RA overspreading the region from west to east between 00 and 06z. Southwest winds becoming northwest between 06 and 12Z Friday.

Friday...High confidence.

Becoming VFR from NW to SE during the morning. Gusty N winds behind a cold frontal passage.

KBOS Terminal...High confidence in trends. Moderate confidence in timing.

KBDL Terminal...High confidence in trends. Moderate confidence in timing..

Outlook /Friday Night through Monday/...

Friday Night through Saturday: VFR. Breezy.

Saturday Night: VFR.

Sunday: VFR. Breezy.

Sunday Night: Breezy.

Monday: Windy with areas of gusts up to 35 kt.

MARINE

Forecaster Confidence Levels...

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

Through Friday...High confidence.

Winds increasing out of the south/southwest this morning. Moderate sustained winds between 15-25 kt with gusts up to 30 kt. Winds shift to the northwest tonight as a cold front moves over the coastal waters with a round of showers. North to northeast winds expected for Friday. Small Craft Advisory criteria through the end of this week with a few gale force gusts possible on the edge of the outer marine zones.

Outlook /Friday Night through Monday/...

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

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

Saturday Night: Winds less than 25 kt.

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

Sunday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft.

Monday: Strong winds with gusts up to 35 kt. Seas up to 5 ft.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until midnight EDT tonight for ANZ230-236. Small Craft Advisory until 8 AM EDT Friday for ANZ231>234-251. Small Craft Advisory until 5 PM EDT Friday for ANZ235-237. Small Craft Advisory until 2 PM EDT Friday for ANZ250. Small Craft Advisory until 8 PM EDT Friday for ANZ254>256.