textproduct: Portland

SYNOPSIS

Weak low pressure over the region will maintain cool temperatures with light scattered showers today. High pressure re-builds Sunday to Monday, returning dry and sunny conditions. Cool nights will bring chances for morning frost in rural valleys away from urban cores this weekend into early next week. Next chances for light rain arrive Tuesday to Wednesday. Temperatures trend warmer late in the week as an upper-level ridge amplifies over the region.

LONG TERM...Tuesday through Saturday

High pressure will maintain mostly dry conditions with seasonable temperatures Tuesday to Wednesday for the majority of the area. An exception would be southwest Washington and the north Oregon Coast Range and Cascades, where chances for light rain increase to 10-30% as a weak cold front over the coastal waters attempts pushing inland. Even if this front is able to move inland, it would be decaying, which suggests rain amounts would likely be very light. Chances for 48 hour rain totals exceeding 0.10 inch from 5 AM Tuesday to 5 AM Thursday are 20-40% across southwest Washington and the north Oregon Coast Range and Cascades, and 5-15% across the Willamette Valley. Will also see increased cloud cover by Wednesday from this weak front, which will keep overnight temperatures warmer and reduce the threat of widespread frost by Tuesday night/Wednesday morning.

By Thursday and Friday, the majority of ensemble members are in agreement that upper-level ridging will amplify again over the western U.S., bringing above-average 500 mb heights. This will result in temperatures rebounding to the low to mid 70s across interior valleys at the end of the week. -10

AVIATION...Through 18Z Sunday

Radar imagery continues to show light, scattered showers across the airspace as weak low pressure remains over the region. These showers are expected to linger through around 00Z Sunday, but am not expecting any impacts from these showers. Therefore, expect predominately VFR conditions across the airspace through the majority of the TAF period. High pressure will slowly re-build through daytime hours which will bring a return of drier conditions along with clearing skies. Northwesterly winds around 3-7 kt for all terminals today.

Tonight, clearing skies and calm winds will support temperatures falling towards 33-36 degrees F for more rural areas and sheltered valleys. Areas that are able to cool down to these temperatures may see frost development on metal surfaces. Could also see some IFR/LIFR conditions developing between KSLE and KEUG starting around 12Z Sunday. Any lowered flight conditions that do manifest are expected to improve towards VFR around 17Z-19Z Sunday.

KPDX AND APPROACHES...VFR with very light showers through around 00Z Sunday. Skies expected to clear through the daytime which will result in cooler overnight temperatures. Northwesterly winds 3-5 kt. /42

MARINE

Buoy observations as of early Saturday morning show northwesterly winds around 10-20 kt with gusts up to 25 kt, along with seas around 8-10 ft at 10 seconds. The Hazardous Seas Warning for the waters north of Cape Falcon and beyond 10 NM as been cancelled given that seas have now fallen below 11-12 ft. However, Small Craft Advisories remain in effect for most of the waters through this afternoon for steep and choppy seas. Winds will gradually weaken today and seas subside to 7-9 ft by this evening.

Tonight into Sunday, will see a renewed round of small craft conditions as tightening pressure gradients from a thermal trough result in breezy north/northeasterly winds with gusts up to 25 kt for the waters south of Cape Falcon. Seas remain steep and choppy around 7-10 ft at 9 seconds during this time, steepest as you go beyond 10-20 NM. Winds weaken on Monday and remain northerly through early Tuesday morning, before turning more southwesterly mid-week ahead of an approaching weak front. -10

PQR WATCHES/WARNINGS/ADVISORIES

OR...Frost Advisory from midnight tonight to 9 AM PDT Sunday for ORZ104-106-113-117-121-123>125.

WA...Frost Advisory from midnight tonight to 9 AM PDT Sunday for WAZ205-208.

PZ...Small Craft Advisory until 8 PM PDT this evening for PZZ210.

Small Craft Advisory until 2 PM PDT this afternoon for PZZ251- 252-271>273.

Small Craft Advisory from 2 PM to 11 PM PDT Sunday for PZZ252- 253.

Small Craft Advisory from 2 AM to 11 PM PDT Sunday for PZZ272- 273.