textproduct: Gray - Portland

WHAT HAS CHANGED

Adjusted the near term forecast to observational trends with no significant changes. Much of the area stayed clear overnight leading to some radiational cooling, but despite a bit of a colder start temperatures are still expected to quickly rise through the morning, with widespread 40s for the afternoon. Also of note, onshore flow has led to some lower clouds this morning and isolated patchy fog, but this should be short lived as temperatures begin to rise and mix them out.

KEY MESSAGES

1. Warmer temperatures in store today, followed by colder weather and a little light snow on Sunday.

2. Low pressure brings the next chance for widespread precip late Tuesday and Wednesday.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION... A warm front will move through the forecast area prior to 12z this morning. The front will come with little fanfare other than some clouds, particularly in the mountains along with a little bit of fog elsewhere. The end result will be warmer temperatures with highs in the 40s, possibly as high as 50 degrees in the Merrimack Valley of NH. As far as precipitation goes, a brief period of showery weather will be possible, mainly across northern NH. Winds will become a bit gusty this afternoon, with southerly gusts around 25 MPH.

Much colder air is expected in the wake of a cold front later Saturday night and Sunday. At the same time a short wave trough will traverse northern New England on Sunday. Enough moisture and lift will be present to aid in a little light snow which should not amount to more than two inches at any given location.

KEY MESSAGE 2 DESCRIPTION...

The Arctic high pressure system crosses through New England early in the week. It leaves behind a cold air mass as low pressure rides eastward into New England. Models continue to bring moisture into New England with this system, but there remains some discrepancy on how much moisture reaches into New England, and where different precip types will fall.

Warm air will try to make a northward push with the system, but will have the cold airmass stubbornly in place ahead of it. This it likely to lead to snow north, rain south, and a wintry mix in between. This system will be different from the all snow systems we've become accustomed to lately, and much uncertainty remains on where these different precip types will set up.

Trends from past systems this winter would hint at the colder air winning out more, but this would also come with a northern edge into our forecast area should most of the precip that does fall fall as snow. So we'll continue to monitor the trends as we get closer to the system.

Another wave of low pressure is then possible late in the week, and would likely have even more warm air to work with. However, we'll approach these systems one at time for now.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Through 06z Sunday... An approaching cold front may bring scattered rain and snow showers to the mtns today. Local MVFR or lower conditions are possible, mainly at HIE. Otherwise, VFR conditions are expected with gusty southerly winds.

Outlook...

Sunday: A weak low pressure system will pass across northern New England with a little light snow which many bring cigs and vsbys down to IFR for a relatively short periods of time.

Sunday night thru Monday Night: Improving to VFR in the evening and overnight as high pressure settles overhead.

Tuesday and Tuesday Night: MVFR to IFR ceilings possible by late Tuesday with the chance of SN reducing visibility.

Wednesday: IFR and mixed precip possible.

Wednesday Night - Thursday: Some improvement in conditions, but MVFR still possible.

Thursday night - Friday: More IFR possible with snow and mixed precip.

MARINE

Southwest winds will increase early this morning ahead of an approaching cold front. Warm advection over cold ocean waters will struggle to mix down the strongest wind gusts, but a period of SCA gusts is expected today. Winds and seas will begin to diminish tonight. However, SCA conditions are once again expected Sunday night into early Monday.

Arctic high pressure crosses the waters during the day on Monday, with low pressure riding east across the waters late Tuesday and early Wednesday. SCA to low end gales are possible in southerly flow with this system. Weak high pressure then crosses on Thursday.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...Small Craft Advisory until 9 PM EST this evening for ANZ150- 152-154. Small Craft Advisory until 9 PM EST this evening for ANZ151- 153.