textproduct: Gray - Portland

WHAT HAS CHANGED

No significant changes needed for this morning update. Just freshened up the near term as showers continue to push through the area with low pressure now centered offshore. Also, freshened up the aviation discussion to reflect the 12Z TAF package.

KEY MESSAGES

1. Low pressure will continue moving southeast across the region, leading to scattered showers and maybe a few rumbles of thunder through the morning. A few more isolated showers are possible later this afternoon.

2. A warming trend with slightly above average temperatures to end the week

3. Chances for precipitation Tuesday and next weekend, but no day is expected to be a washout

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

A surface low will continue to drop southeast into the Gulf of Maine this morning with the upper low close on it's heels. This will lead to another round of showers rotating north to south through the forecast area from around 07z to 15z or so this morning. The lowest probabilities for showers this morning will be across the Kennebec River Valley and Midcoast areas which will be further east than the best synoptic forcing. While thunder will not be as widespread, a few rumbles will be possible with a little bit of instability floating around.

Most of the precipitation will move out in the morning, but we could have a few more diurnal showers develop in the afternoon. There will be some modest instability again, so a thunderstorm or two is not out of the question but coverage will also be limited.

This morning, lows will mainly range from the upper 30s north, to the low/mid 40s south. Afternoon highs will be on the cooler side once again, ranging from the upper 50s to the mid 60s. Lows tonight will then be similar to this morning, in the mid to upper 30s to mid 40s.

KEY MESSAGE 2 DESCRIPTION...

The upper-level troughing finally releases its grip on New England by Tuesday. This happens as the omega block pattern breaks down, and the anomalous ridge over Canada is squashed southeast into the Northeast U.S. For local sensible weather, this should result in a multi-day period of tranquil conditions and near seasonable temperatures as a 1025 mb high pressure crests over the region. Flow will be light so sea breeze formation will be possible each day Tuesday onward. Much of the week will feature highs in the 70s, but there is a chance temperatures could reach the 80s by Thursday- Friday as it becomes warmer aloft. It should generally be a pleasant airmass with dew points in the 50s, but humidity may become a bit more noticeable by next weekend depending on the shortwave's timing.

KEY MESSAGE 3 DESCRIPTION...

There are chances for precipitation on Tuesday and next weekend, but neither day looks to be widespread or long duration chances. On Tuesday, the remnants of the weekend's cold pool will still be in the vicinity. Hi-res guidance coming into range is showing rather steep low-level lapse rates ~9.0 C/Km, paired with freezing levels still hovering around 800 mb. This looks to be enough to generate a few hundred J/Kg of CAPE, which may be enough for downpours and isolated thunderstorms.

AVIATION /10Z MONDAY THROUGH FRIDAY/

Fog and low ceilings will lift around 12Z this morning bringing quick improvement to VFR. Brief MVFR conditions will remain possible this morning and this afternoon as isolated showers remain in the area. VFR prevails tonight, but some valley fog is possible.

Outlook:

Tuesday: VFR with isolated showers possible on the coastal plain in the afternoon. Light north winds becoming southerly on the coastal plain during the afternoon.

Tuesday night: VFR expected.

Wednesday/Wednesday night: VFR with light winds.

Thursday/Friday: High pressure is favored with VFR conditions.

MARINE

Conditions remain below SCA levels through tonight. A weak low pressure system tracks southeastward through the Gulf of Maine this morning. A small high pressure system passes through tonight.

Fair weather is expected Tuesday through Friday with winds and seas remaining below SCA thresholds.

GYX WATCHES/WARNINGS/ADVISORIES

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