textproduct: Gray - Portland

WHAT HAS CHANGED

No significant changes with this forecast package.

KEY MESSAGES

1. Strong cold front moves across the forecast area on Monday with wind gusts of 25 to 35 MPH Monday afternoon and evening. Winds should stay up enough at night to preclude frost in the zones where the growing season is still ongoing.

2. Colder and breezy conditions continue into Tuesday with the coldest night of the season so far possible Tuesday night. Many locations south of the mountains could see frost and possibly their first freeze of the season.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Today will be another fair weather day with increasing clouds and highs in the 60s after valley fog lifts. A wave of low pressure passing to our south late today and tonight should remain to our south as per strong model consensus.

Temperatures tonight should be warm enough to preclude frost in the zones that are still active.

On Monday, a strong cold front sweeps across the CWA. The preceding air mass will be quite dry so we don't expect much in the way of precipitation with the front. However, there could be a line of gusty showers with the front in some areas, especially northern zones. Winds in the wake of the front during Monday afternoon should gust 25 to 35 MPH, with some forecast sounding profiles supporting a few 40 MPH gusts. The gusts will gradually wane overnight, but should stay up enough to preclude frost development in the zones that are still active.

KEY MESSAGE 2 DESCRIPTION...

Tuesday will be a cool, breezy, and crisp-feeling fall day as cold advection advection continues following Monday's cold front. Forecast soundings support gusts of 25 to 30 mph for much of the day, and wind chills could be in the 20s and 30s during morning work/school commute time. So make sure to grab the coat. High temperatures will be limited to the 50s south of the mountains and 40s across the north. For hikers, higher elevations will likely see subfreezing wind chills through the day.

Winds ease Tuesday evening and Tuesday night as high pressure builds overhead. Skies will be mostly clear, and if winds can go light enough, good radiational cooling could bring the coldest night of the season so far with frost and possibly the first freeze for many locations south of the mountains. Widespread lows in the 30s are possible with some 20s in the northern valleys and more sheltered locations.

The upper-air pattern indicates troughing over much of eastern Canada and extending somewhat into the Great Lakes and Northeast from mid to late week. Shortwaves could push a couple of fronts through the area to potentially bring some rain showers, but virtually all ensemble members indicate only light rainfall amounts possible. Ahead of these fronts, winds will be mainly out of the south to southwest, so temperatures will start to recover. Highs Wednesday should be in the 50s to lower 60s and then guidance favors most in the 60s Thursday and Friday, possibly around 70 in southern NH. Ensembles then favor mostly dry conditions heading into next weekend with high pressure building toward the Northeastern US.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

Widespread VFR conditions expected during the day Sunday after early morning valley fog lifts. Winds go onshore at 5 to 10 KT during the late morning and afternoon hours. MVFR and IFR conditions are expected tonight, mainly on the coast northwestward into central ME. These should lift Monday morning as a front approaches and moves through. Westerly wind gusts of 25 to 32 kt are then expected Monday afternoon and evening.

Outlook:

Tuesday: VFR with west to northwest winds gusting around 25 kt.

Tuesday night: IFR or lower valley fog possible at HIE and LEB. Otherwise VFR.

Wednesday-Thursday: Mainly VFR with a few showers possible toward HIE.

MARINE

Winds and seas are expected to remain below SCA thresholds thru the rest of the weekend. We will have to keep an eye on moisture return to see if fog can develop fast enough to advect over the waters by early Mon.

A strong cold front crosses the waters Monday and will bring wind gusts 25-30 kts into Tuesday. Wave heights will respond, building to around 5 ft. An SCA is has been issued for Monday afternoon through Tuesday afternoon.

Tuesday night-Sunday... High pressure brings improving conditions Tuesday night, and then a couple of fronts may bring additional periods of SCA conditions from mid to late week, especially Wednesday into Wednesday night. High pressure looks to build toward New England toward next weekend.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...Small Craft Advisory from 2 PM Monday to 5 PM EDT Tuesday for ANZ150>154.