textproduct: Gray - Portland

WHAT HAS CHANGED

No significant changes with this forecast update.

KEY MESSAGES

1. A warming trend begins today with above normal temperatures likely Monday through Wednesday. Chances for precipitation will be limited until a frontal system crosses Tuesday and Wednesday bringing mainly rain and little in the way of impacts.

2. The second half of the work week into the weekend will feature more seasonable temperatures with the potential for active weather to continue.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

High pressure builds in from the southwest this morning before shifting offshore this afternoon. Return flow will advect warmer air into the region allowing for highs to range from the upper 30s north to upper 40s across the south. Temperatures continue to climb Monday ahead of a cold front that will sag into the area Monday night and Tuesday. Highs on Monday will range from near 50F across the north to the low 60s across southern New Hampshire.

The cold front will stall over New England Tuesday with a wave of low pressure tracking along the front through Wednesday. The majority of ensemble members suggest mainly rain will be likely across the northern two thirds of the area Tuesday with the southern third seeing lower chances for rain. Depending on how far south the cold front gets, there will be some potential for a wintry mix near the Canadian Border and in the mountains Tuesday before a change to rain. The wave of low pressure will track through the St Lawrence Valley Wednesday night and into the Canadian Maritimes Wednesday afternoon. This track will place much of the area within the warm sector allowing for highs on Wednesday to range from the mid 50s north to upper 60s across southern NH. There will be continue chances for rain Wednesday through Wednesday night with the highest chances confined to the foothills and points northward. As low pressure exits into the Canadian Maritimes the attendant cold front will cross the area late Wednesday into Wednesday night that may allow for rain showers to end as snow showers. While there remains a large spread in QPF Tuesday through Wednesday, the high end amounts are around 1 inch and will not have any impacts. Ensemble means generally range from 0.75 inches across the mountains and north to less than 0.5 inches south of the foothills.

KEY MESSAGE 2 DESCRIPTION...

Towards the end of the week, a 500mb trough should move over the northeast and should allow for more seasonable temperatures. High pressure may try to shift southward as well, with models not quite certain yet on how far south the high pressure will get. If the high stays to the north, more damp and rainy weather looks to be in the forecast for Thursday, while a southerly high pressure track would keep the northeast dry. Low pressure looks certain to work its way into New England by Friday morning, with wintry precipitation possible. The pattern remains active for next weekend as well, with ridging allowing for potentially some above-average temperatures in store.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

VFR prevails through tonight, while SW winds gust 15-20 kts this afternoon.

Outlook...

Monday: Mainly VFR with SW winds gusting 15-20 kts. MVFR cigs may develop in the mountains Monday afternoon. Clouds thicken and lower Monday night with MVFR possible at all sites by Tuesday morning

Tuesday: Generally MVFR with IFR possible in low cigs and rain.

Wednesday: Conditions slowly improve as precipitation tapers off during the day. Some light snow showers may create brief restrictions at night/early Thursday.

Thursday: Conditions improving to VFR as lingering showers come to an end.

MARINE

High pressure builds in from the SW this morning before shifting east of the waters this afternoon. SW flow will increase bringing SCA conditions this afternoon through Monday. Winds and seas generally drop below SCA thresholds Monday night and Tuesday. Low pressure passing north of the waters Tuesday night will bring increasing SSW flow with SCAs likely needed through Wednesday and the potential for gusts to reach Gale force over the outer waters. A cold front crosses the waters Wednesday night with winds shifting offshore. Winds and seas gradually diminish Wednesday night and into Thursday.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...Small Craft Advisory from 2 PM Sunday to 2 PM EDT Monday for ANZ150-152-154.