textproduct: Portland

SYNOPSIS

Areas of fog and low clouds Sunday morning will give way to sunny and warm conditions in the afternoon. Temperatures trend cooler Monday through Friday as upper level troughing develops over the Gulf of Alaska. Chances for rain have increased Thursday night into Friday to 40-60% as troughing attempts pushing into western Washington and western Oregon.

LONG TERM...Wednesday night through Saturday night

The forecast remains dry and mild Wednesday night through Thursday afternoon as dry southwest flow aloft persists. However, chances for rain Thursday night into Friday have increased due to an uptick in the number of ensemble members showing at least some QPF over the area with an approaching upper level trough. Chances for precipitation falling within a 24-hour period ending at 5 PM Friday have increased to 40-60%. Exact timing and rain amounts remain uncertain, and around 30-40% of ensemble guidance continues to show no rain at all over the Willamette Valley. Therefore, confidence is only moderate and it is too soon to tell if Friday will for sure be a wet day or not. Regardless of the outcome, chances for rain decrease significantly Friday night into Saturday to less than 15%, suggesting multiple days with rain are unlikely.

It is also worth mentioning that chances for frost increase over the Upper Hood River Valley Friday night and Saturday night when there is a 30-50% chance for overnight lows around 37 degrees or colder, mainly in the Parkdale area. Probabilities are around 10% in Odell and 1-5% in Hood River. Those with sensitive outdoor vegetation in this area should monitor the forecast over the coming days. -23

AVIATION...Through 12Z Monday

Areas of fog and low stratus continue to expand across the area this morning with calm winds in place. LIFR to IFR visibilities and/or ceilings are impacting all TAF sites as of 1100-1130Z Sunday, except at KHIO which will likely hold off on low cloud development until approximately 13Z Sunday. Similar to what was observed yesterday, fog and low clouds will lift sometime between 19-21Z Sunday and give way to mostly clear skies and VFR conditions.

Winds will stay fairly light through the TAF period, aside from KONP where northwest winds will increase this afternoon with gusts up to approximately 20 kt.

KPDX AND APPROACHES...Expect low stratus with ceilings ranging between 500-800 feet through this morning, beginning sometime between 12-13Z Sunday. Similar to yesterday, skies should rapidly clear out sometime between 19-20Z Sunday and bring a return to VFR conditions. Calm winds this morning should become predominately northwest around 3-6 kt this afternoon. -23

MARINE

High pressure over the waters will maintain northerly winds through this weekend. Northerly winds peak in strength Sunday afternoon and evening when there is a 50-90% chance for maximum wind gusts of 21 kt or slightly stronger across the waters, with the highest chances across the inner waters out to 10 NM offshore. Given wind gusts of this magnitude are not expected to be frequent or widespread, Small Craft Advisories are not anticipated at this time. Significant wave heights will remain around 3 to 5 ft through the weekend, mainly driven by a persistent northwesterly swell with a dominant wave period near 7 seconds.

Northerly winds are expected to linger Monday through Wednesday, with wind gusts generally staying under 20 kt. A long period west-northwesterly swell is set to arrive either Monday afternoon or evening, pushing seas up by one to two feet. However, seas will not be particularly steep as the dominant wave period with this swell will be around 11-13 seconds. -23

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...None.