textproduct: Gray - Portland

WHAT HAS CHANGED

No major changes needed this evening as the forecast remains on track. Just tweaked near term trends to align with observations and updated the aviation discussion for the 00Z TAFs.

KEY MESSAGES

1. Mainly fair weather expected tonight through Wednesday night with widely scattered showers and isolated thunderstorms possible Wednesday afternoon with low potential for gusty winds.

2. Showers and storms are likely to end out the week, with mostly dry weather expected over the weekend. Astronomical tides will be at a monthly high, but impacts should remain minimal.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Other than locally dense valley fog tonight the weather will be fair. Radiational cooling will bring temperatures down into the 50s in outlying areas, with a few spots in northern NH possibly reaching the upper 40s. Have heavily blended in the MET and MAV guidance for lows.

A weak short wave trough will approach northern New England Wednesday. This feature coupled with at least weak instability should allow for widely scattered showers and isolated thunderstorms during the afternoon hours. With SFC dewpoint depressions around 20F gusty winds could occur in convective showers and storms. However, coverage will be widely scattered and most locations will likely remain dry. Valley fog will be likely once again late at night.

KEY MESSAGE 2 DESCRIPTION...

A weak trough axis swings into the area Thursday afternoon and is likely to persist through Friday. During its passage, showers and storms are possible, but PWATs in the range of 1.1-1.5 inches should allow for showers to be fairly scattered rather than more widespread.

In addition, we will need to keep an eye on the high tides for Thursday. Astronomical tides are high for the month, and the tide gauges will be close to reaching minor flood stage. However, light offshore winds and very low wave heights could allow for some high water along the coast, but otherwise impacts should be minimal.

Over the weekend, a mid-level ridge moves into the area. Ridging and high pressure should allow for dry and pleasant weather, with high temperatures forecast near 80F.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

Through 00Z Thursday...Valley fog at HIE and LEB likely tonight and Wednesday night. The seabreeze will likely come ashore during the afternoon at coastal terminals. Widely scattered gusty showers and possibly a thunderstorm Wednesday afternoon may bring about TEMPO MVFR restrictions, but confidence is too low to include in the TAFs at this time.

Outlook:

Thursday-Friday: Periods of MVFR possible due to showers and thunderstorms.

Saturday-Sunday: VFR Expected.

MARINE

Winds and seas will largely remain below SCA criteria through the week as a series of generally weak cold fronts cross the waters. Conditions may come close to SCA criteria briefly Friday night and into Saturday.

GYX WATCHES/WARNINGS/ADVISORIES

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