textproduct: Gray - Portland

WHAT HAS CHANGED

No significant changes with this forecast update.

KEY MESSAGES

1. Cool and cloudy today with intermittent rain and snow showers. Additional chances for rain and mountain snow showers arrive Wednesday night into Thursday with a drying trend SW to NE.

2. A moderating trend continues through the end of the week, with weekend conditions trending drier. These drier conditions will allow for increasing fire weather concerns this weekend.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Low pressure over the eastern Great Lakes will lift a warm front towards the forecast area today before sliding southeast of southern New England this evening. Clouds will thicken and lower early this morning with light precipitation overspreading the area west to east starting around day break. Thermal profiles continue to suggest precip across the higher terrain of SW New Hampshire towards the White Mountains may start out as some snow while incoming 00Z guidance is less bullish on any accumulating snow than previous runs. Temperatures will rise into the 40s through the morning with chances for intermittent rain showers or drizzle continuing into this evening. Highs will be rather uniform across the area in the 40s.

As low pressure continues to track southeast away from southern New England tonight a short wave diving SE out of Canada will swing across northern Maine through Thursday. Models are in relative good agreement this short wave will aid in the formation of an inverted trough that will linger through Thursday. The approaching short wave and inverted trough will continue precipitation chances across the mountains through central Maine Wednesday night into Thursday while south-central NH and SW Maine see clearing skies Thursday morning. These areas that see sunshine should experience mixing allowing for min RH to drop around 30 percent across southern New Hampshire and far SW Maine along with winds gusting to around 20-25 mph.

KEY MESSAGE 2 DESCRIPTION...

A weak blocking pattern over the Great Lakes should allow for seasonable temperatures at the end of the week, with high temperatures forecast mostly in the 50s Thursday, Friday and Saturday. Dry surface air looks to funnel in from the northwest, and will allow for a diurnal breeze likely on Thursday. Winds do look calmer for Friday and Saturday. Minimum RH values look to be in the 25-45% range for all three days at this time. These aforementioned dry and breezy conditions may allow for hazardous fire weather, with camp and bush fires potentially spreading easily and becoming harder to extinguish.

For early next week, temperatures look to warm a little as the mid-level block previously mentioned flattens and ridging continues to remain stationary over the Great Lakes. In addition, some scattered showers can not be ruled out either for late Sunday night.

AVIATION /02Z WEDNESDAY THROUGH SUNDAY/

Through 06z Thursday...Clouds thicken and lower from SW to NE with CIGs approaching MVFR at all sites by 18Z. Light precipitation overspreads the area SW to NE in the form of rain and snow showers or possibly drizzle. Uncertainty for coverage of IFR, which may remain SCT until this evening. With showers exiting, cigs will be the primary restriction into Wednesday night.

Outlook:

Thursday: Chances for rain and mountain snow showers will bring the potential for MVFR/IFR across the mountains and Kennebec Valley. Southern NH TAF sites and PWM likely see prevailing VFR with gusty NW winds.

Friday-Sunday: Mainly VFR conditions expected.

MARINE

Winds and seas generally stay below SCA thresholds through the end of the week. Southerly winds increase today as a warm front approaches the waters while gusts will be less than 25 kts. Winds turn offshore Thursday and will largely remain offshore into the weekend.

GYX WATCHES/WARNINGS/ADVISORIES

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