textproduct: Gray - Portland

WHAT HAS CHANGED

Updated observations and let the Winter Weather Advisory expire across NH and ME outside of the mountains. Temperatures have increased such that additional icing or wintry weather will be more isolated across northern zones. This morning's sounding did have some elevated instability, and will see a few additional isolated rumbles of thunder in some showers before early afternoon.

KEY MESSAGES

1. Slippery travel possible for the morning commute in the winter weather advisory area, especially higher elevations.

2. Temperatures remain above normal with rain likely from Saturday night into Sunday night. A return to drier weather is then likely into the middle of next week with near to a little below normal temperatures.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION... Freezing rain taper through the late morning hours in the remaining advisory area as temperatures rise. Impacts look fairly minimal. Slickest conditions will be at higher elevations where temperatures will be colder.

We lowered high temperatures to be more in line with CAMs for today on the ME coastal plain and also central zones. The low level cold air mass is going to be tougher to dislodge than the NBM suggests (at least during the daylight hours). Temperatures elsewhere remain the same as southern and western NH should warm up appreciably.

Cold front sweeps across the forecast area around midnight tonight with little fanfare. However, the southwesterly flow ahead of the front should allow temperatures across central and coastal ME to finally warm into the 50s.

Another high pressure ridge pushes down from the northeast Saturday allowing winds to once again go northeast area-wide making for cooler temperatures but dry weather.

KEY MESSAGE 2 DESCRIPTION... Saturday will feature dry conditions with partly sunny skies as an H5 ridge axis crests overhead. Above average temperatures are expected with highs into the 40s across the north and along the immediate coast with 50s/60s inland south of the mountains. This ridge will begin exiting to the east on Saturday night as stacked low pressure exits the Upper Great Lakes Region and towards Quebec. This will send a sfc warm front northward, allowing for increasing clouds along with an increasing chance for light rain by early Sunday morning. Some sleet and/or freezing rain is possible across mainly the mountains and towards the Canadian Border but it should be just plain rain elsewhere as lows fall into the middle to upper 30s.

The warm sector will move into the region on Sunday ahead of a trailing cold front, which will cross from north to south on Sunday evening and night. A widespread wetting rainfall is expected with high temperatures once again into the 50s and 60s. Rain will end on Sunday evening with lows mainly into the 30s. Mainly dry conditions are then likely Monday through the middle of next week, although some upslope rain and snow showers will be possible due to persistent northwesterly flow. Temperatures will trend to near or a little below seasonable averages.

AVIATION /13Z FRIDAY THROUGH TUESDAY/

Through 12z Saturday...IFR conditions early this morning will give way to VFR across southern NH starting around 18z which will then spread slowly north and northeast. However, portions of central and Midcoast ME won't lose the low clouds and fog until evening when a cold front moves through. The mountains may remain MVFR for a good portion of tonight. VFR conditions are expected Saturday daytime with northeast winds.

Outlook:

Saturday night: Clouds thicken and lower with rain developing. MVFR to IFR likely.

Sunday: MVFR-IFR expected with rain and low ceilings.

Monday: VFR likely, chance of a stray snow shower in northern New Hampshire.

Tuesday: VFR conditions likely with an isolated chance (<=20%) for a rain or snow shower, especially across southern TAF sites.

MARINE

SCA conditions continue over the eastern waters through midday Saturday. Added a SCA to the southern waters starting this evening through midday Saturday.

Variable SCA level winds are expected Saturday night and Sunday with 4-8ft seas likely through the weekend. Winds shift to easterlies and gradually simmer to sub-SCA levels by Monday night. 3-5ft seas are expected early next week.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Winter Weather Advisory until noon EDT today for MEZ007>009. NH...None. MARINE...Small Craft Advisory until noon EDT Saturday for ANZ150-152. Small Craft Advisory from 6 PM this evening to noon EDT Saturday for ANZ154.