textproduct: Gray - Portland

WHAT HAS CHANGED

The aviation section has been updated for the 12Z TAFs. No changes needed otherwise.

KEY MESSAGES

1. Any showers end by 12z this morning and fog quickly lifts. Westerly wind gusts up to 30 MPH expected today. Frost possible tonight in the mountains.

2. High pressure is likely to continue dry weather through midweek, with a frontal boundary likely to bring rain to the area in the Thursday to Friday morning timeframe.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

A cold front will pass east of the forecast area early this morning. This will bring an end to any scattered shower activity by sunrise. Mixing will commence fairly quickly as well so any fog and low clouds should dissipate early.

A strong pressure gradient will be in place today which will aid in gusty NW winds. BUFKIT soundings indicate the likelihood of 25 to 30 MPH gusts with some potential for a few higher gusts.

Highs should rebound into the 70s at lower elevations downwind of the mountains, with 60s remaining in the mountains with upslope clouds expected. The rest of the forecast area should see a good deal of sunshine.

High pressure quickly moves overhead tonight which will allow for efficient radiational cooling. Areas of frost are possible in the mountains as low temperatures fall into the lower to mid 30s.

The high slowly moves offshore during the day on Tuesday allowing for a light southerly return flow during the afternoon. Highs should be within a couple of degrees of 70F area-wide.

KEY MESSAGE 2 DESCRIPTION...

High pressure over New England will keep the area mostly dry and seasonable on Wednesday and early Thursday. Temperatures look to be in the 70s through the second half of the week. A low pressure system looks to move eastward on Thursday, potentially bringing some rain across the northeast on Thursday afternoon and into early Friday. Models have not quite come into agreement yet for how much rain could be possible, but PWATs are forecast near 1.7" which approaches the 99th percentile for this time of year. High PWATs would suggest showers along this frontal boundary could be efficient rain-producers. With this in mind, it does appear that at least wetting rains are likely, but potentially more meaningful rains are possible as well.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Through 12Z Tuesday...A period of MVFR cigs is possible at HIE this morning, but otherwise VFR is expected today with NW winds gusting 20 to 30 kts. VFR is likely tonight except for HIE and LEB where a period of valley fog will likely occur late tonight into early Tuesday morning to bring IFR or lower.

Outlook:

Tuesday: VFR with light southerly winds.

Tuesday Night: VFR conditions expected.

Wednesday/Wednesday Night: VFR conditions expected.

Thursday/Thursday Night: Restrictions possible in developing SHRA.

Friday/Friday Night: Isolated SHRA may result in possible localized restrictions.

MARINE

A cold front crosses this morning shifting winds out of the NW. These winds will gust around 20 kts with higher gusts closer to the coast as stronger winds over land may push just offshore.

High pressure will keep winds and seas below SCA criteria tonight through at least mid to late week.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Frost Advisory from 2 AM to 8 AM EDT Tuesday for MEZ007. NH...Frost Advisory from 2 AM to 8 AM EDT Tuesday for NHZ001-002. MARINE...Small Craft Advisory from 11 AM this morning to 5 PM EDT this afternoon for ANZ151-153.