textproduct: Gray - Portland

WHAT HAS CHANGED

No significant changes since the previous forecast cycle.

KEY MESSAGES

1. Scattered showers remain possible through this evening with a drying trend Friday into Friday night.

2. We will remain mainly dry through at least Saturday, but unsettled weather should return late Sunday into Monday.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

The combination of some weak daytime instability and the upper level low/cold pool aloft will continue to result in some scattered showers through this evening, before becoming more isolated overnight. Low temperatures will be into the lower to middle 50s. Patchy fog is likely overnight, especially across the valleys and in locations that received recent rainfall.

Low pressure will exit well to our northeast on Friday as surface high pressure builds to our south. This will allow for a brighter and warmer day with high temperatures into the lower 80s under partly cloudy skies. A few diurnally driven showers cannot be ruled out though as we remain under weak cyclonic flow. Friday night will feature dry conditions with low temperatures into the 50s.

KEY MESSAGE 2 DESCRIPTION...

An upper level ridge axis will cross the region on Saturday which will keep the area mostly dry, but a few isolated mountain showers/storms will be possible. Temperatures will increase on Saturday with the ridge moving overhead, with highs expected to range from the mid/upper 70s north, to the low/mid 80s elsewhere.

On Sunday, we transition back into southwest flow aloft as the next trough approaches slowly from the west. This will keep temperatures similar to Saturday but with abundant cloud cover in place, it could be just a touch cooler. The next chance for widespread rainfall will then move in late Sunday, potentially sticking around through Monday evening/night. As of now, this system doesn't look to be a prolific rainmaker with NBM probabilities of a half inch or greater only maxing out in the 20 to 50 percent range, but most will see at least some rain with the best chances in the foothill and mountains. After this system exits, the rest of the week looks fairly quiet with normal to above normal temperatures.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Through 18Z Friday: MVFR to IFR restrictions will be common tonight due to low ceilings and overnight FG. Winds will be light out of the north. Mainly VFR conditions are then expected for much of Friday, although a few scattered afternoon showers may result in brief restrictions. Winds will be out of the NNW at 5-15 kts. No LLWS is anticipated through the period.

Friday Night: VFR conditions expected outside of possible valley FG. Light and variable winds expected.

Outlook...

Saturday: Largely VFR conditions expected. Local/brief MVFR or lower possible under any isolated mountain showers/thunderstorms.

Sunday-Monday: Increasing chances for showers and storms may lead to areas of MVFR/IFR restrictions late in the day Sunday through Monday.

MARINE

Winds and seas will continue to diminish through this evening with conditions below SCA criteria expected tonight through Friday night.

Winds and seas are generally expected to remain below SCA thresholds thru the remainder of the forecast period. However another round of fresh onshore winds are possible Sun, and gusts may approach 25 kt outside of the bays.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ150- 152>154.