textproduct: Gray - Portland

WHAT HAS CHANGED

Wintry precipitation has ended and therefore the winter weather advisory has been allowed to expire. Lingering slippery travel conditions will remain possible through this morning until temperatures rise well above freezing.

KEY MESSAGES

1. Temperatures warm quickly this morning with highs in the 40s to 50s today.

2. A backdoor cold front brings cool air back to the region on Thursday, setting the stage for the next system Thursday night and Friday.

3. A battle between warm and cool airmasses continues through the weekend.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Zonal flow will usher in drier air aloft this morning with skies turning mostly sunny. Temperatures will warm quickly this morning under sunny skies with highs pushing into the upper 40s to low 50s south of the mountains. Northern Valleys will warm into the upper 30s to mid 40s.

KEY MESSAGE 2 DESCRIPTION...

As has been discussed for the last few days, high res guidance has taken on a cooler consensus for Thursday than most global guidance was showing earlier in the week. A backdoor cold front looks to move through Maine and eastern New Hampshire during the day on Thursday, and through the rest of New Hampshire Thursday night. This drops temps back into the 30s and then the 20s. Low clouds and some sprinkles are also likely to accompany the passage of the front.

This cooler air mass sets the stage for the next system that slides eastward into the forecast area Thursday night into Friday. This looks to be another messy one, with a wintry mix across southern and central New Hampshire, and snow more likely toward the north and east. A northern edge likely cuts through the forecast area again with this system.

Precip type zones, and a northern cutoff will be the main forecast challenges going into this system. Steady precip likely then winds down during the morning on Friday, but an extended period drizzle or freezing drizzle is possible from midday Friday through early Saturday.

KEY MESSAGE 3 DESCRIPTION... A repeat of the forecast progression for late this week is increasingly likely to play out again this weekend. High res guidance and the NBM shows highs cruising into the 50s for much of the area, while the pattern suggests that a cold air dam and easterly flow will thwart this taste of spring. It will be very hard for most areas outside of the Connecticut Valley to warm up without any mechanical mixing, which most likely comes in the form of a passing cold front Saturday night. This opens the door for Sunday to see warmer temps with highs in the upper 40s and low 50s, but Saturday looks to be more in question.

A more substantial warm up is possible early next week as a ridge builds across the eastern US. We are right to be suspicious of this with all the sources of cool air nearby, but this set up does look more favorable for a bonafide warm up into northern New England than the one over the next few days does.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

Through 12Z Thursday: Mainly VFR from 12Z today until 12Z Thursday. Winds will be out of the W-SW at 5-10 kts. No LLWS is anticipated through the period.

Outlook:

Thursday: MVFR conditions possible across Maine in northeast flow. VFR more likely across NH.

Thursday Night: Areas of IFR possible with snow and mixed precip.

Friday through Saturday: MVFR to IFR ceilings, with drizzle and freezing drizzle increasingly likely.

Saturday Night: Conditions likely improving to MVFR or VFR late.

Sunday - Monday: VFR conditions expected.

MARINE

Winds and seas will remain below SCA thresholds into Thursday morning. SCA conditions are possible in northeast flow behind a backdoor cold front on Thursday through Friday. SCA conditions are then possible in southwesterly flow on Saturday. A cold front then crosses Saturday night. Southwest flow likely resumes Sunday night.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...None.