textproduct: Gray - Portland

WHAT HAS CHANGED

Another quiet morning to start your work week across New Hampshire and western Maine. No major changes were needed for this update other than to freshen up the aviation forecast.

KEY MESSAGES

1. Warmer air arrives today followed by temperature swings Tuesday into Wednesday as low pressure tracks along a front stalled over the area. There will be chances for rain Tuesday into Wednesday with no weather impacts expected.

2. Colder air arrives ahead of the next frontal system that crosses Thursday and Friday. Accumulating wintry precipitation will be possible with this system, particularly across the interior and points northward.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Low pressure tracking through Quebec will lift a warm front across the area this morning bringing mostly cloudy skies early this morning. Cloud cover thins after day break with temperatures warming into the 50s north and 60s south for highs. A cold front will drop south out of Quebec late this afternoon bringing chances for showers in the mountains. The cold front will stall over the area tonight into Tuesday. Temperatures will drop below freezing across northwestern Maine tonight while lows south of the mountains will be in the upper 30s to low 40s.

An area of low pressure will track along the stalled front Tuesday through Wednesday morning. Chances for precipitation will increase late Tuesday morning with the highest chances occuring Tuesday afternoon through Tuesday night. A period of wintry precipitation to start will be possible across far northwestern Maine with rain elsewhere. As low pressure tracks northeast into the Canadian Maritimes Wednesday morning it will drag a cold front across the area early Wednesday afternoon with chances for precipitation diminishing into Wednesday evening. Enough instability may develop across southern New Hampshire and SW Maine ahead of the cold front to bring slight chances for thunder. Rainfall amounts from Tuesday through Wednesday will range from 0.75 to 1.0 inches across the mountains and north to 0.25 to 0.5 inches south of the mountains.

KEY MESSAGE 2 DESCRIPTION...

A very active end of the week is expected with potentially two more systems on tap. A mid-level trough looks to inch southward, following the Tuesday-Wednesday system mentioned in Key Message 1. A low appears to develop in the central US, and may allow for warmer air to usher into the northeast as the low approaches the region by Thursday afternoon. Models are still uncertain about how far south the cold air reaches and how much warm air gets advected. A high positioned farther south would allow for more snow and wintry mix, with a wetter but still wintry solution if the high tracks further to the north. In addition, pattern recognition indicates that a cold air dam may set up which should also increase chances to see wintry precipitation at least in the interior.

For the weekend, Saturday will likely be the drier day of the two, but there's already good model agreement with low tracking across Canada with a cold front approaching from the west increasing precip chances going into Sunday. There are a few colder ensemble members, but most currently favor rain as the ptype.

AVIATION /12Z MONDAY THROUGH FRIDAY/

VFR prevails at most terminals through early tonight before the next system approaches. Ceilings will then lower to IFR/MVFR categories with increasing precipitation chances late tonight into Tuesday morning.

Outlook:

Tuesday-Tuesday night: Widespread rain is likely along with fog and low ceilings. Restrictions ranging from MVFR to LIFR possible. Brief period of mixed precipitation is possible at HIE early Tuesday before a change to rain.

Wednesday: VFR is possible, but there will be a chance of showers and maybe even a thunderstorm at southern TAF sites as a cold front crosses early afternoon.

Thursday-Friday...Widespread precipitation and restrictions possible. There's potential for mixed precipitation to be a bit farther south to reach other terminals with this system.

MARINE

Southwest winds ahead of a cold front bring SCA conditions to the outer waters into tonight. Some marginal gale force gusts are possible across the far eastern waters this afternoon. Winds drop below 25 kts late tonight through Tuesday and seas drop below 5 ft Tuesday afternoon. The next frontal system crosses Tuesday night and Wednesday with SCAs likely needed and possibly some SW winds gusting to Gale force early Wednesday morning. Winds shift offshore late Wednesday behind a cold front.

Winds shift to northeasterlies Thursday morning with SCA conditions expected through the end of the weekend. Seas of around 3-6ft are expected Thursday through Sunday.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...Small Craft Advisory until midnight EDT tonight for ANZ150-152- 154.