textproduct: Portland

SYNOPSIS

Dry weather with well above normal temperatures for this time of year expected through Monday. Temperatures trend relatively cooler Tuesday through Friday with the return of onshore flow. Conditions will most likely remain dry except for a chance of showers over the Oregon Cascades.

LONG TERM...Tuesday through Friday night

Ensembles are in good agreement that a low pressure system moving through British Columbia will lower upper level heights over the PacNW on Tuesday and allow daytime temperatures to fall back closer to near normal for Tuesday and Wednesday, generally in the low 60s. Dry conditions with mostly clear skies are expected to continue across the majority of the forecast area through next week except for the Oregon Cascades. Ensembles indicate a closed low pressure system will move east through the eastern Pacific approaching northern California Tuesday through Friday. The slow progression of this low will allow for a 10-25% chance of showers over the Cascades Tuesday into Friday with highest chances Tuesday night through Thursday afternoon. Snow levels are mainly expected to remain above pass level, but even if the do drop below pass level, QPF amounts remain on the low side to limit much snow accumulation.

It is also worth mentioning that some areas of early morning frost will be possible each day from Wednesday morning through Friday morning given the light winds and mostly clear skies in place, especially in the Upper Hood River Valley. There's a 40-70% chance of morning low temperatures of 36 degrees or colder in the Upper Hood River Valley each morning. There's a 15-35% chance for the interior lowlands outside of the Portland metro area, which only has a 5-10% chance (generally east of Hillsboro to Gresham and Oregon City to the Columbia River). Anyone with sensitive outdoor vegetation that is susceptible to frost damage should stay up-to-date on the temperature forecast over the coming days and monitor for potential Frost Advisories. -03

AVIATION

Late this evening widespread VFR conditions persist across the region with ample high cloud cover AOA 20-25kft. While these conditions are expected to continue at most terminals, coastal sites like KAST and KONP may be an exception with a 40-50% chance for the development of IFR/LIFR conditions starting around 10Z-14Z Sunday. KEUG also has a slight chance (10-20%) to see some IFR/LIFR conditions as well but these probabilities are lower at all other terminals. Any lowered flight conditions that do develop should scour out around 16Z-18Z. Winds generally remain below 5-10 knots, however, KTTD will see easterly winds increase with gusts up to 20-25 knots at times on Sunday.

KPDX AND APPROACHES...VFR flight conditions are expected with high clouds streaming overhead. Expect light NW winds to eventually turn easterly later Sunday morning with a sporadic gusts around 10-15 knots possible during the afternoon - stronger winds out near KTTD. -99

MARINE

High pressure remains anchored over the waters and is resulting in rather benign conditions. Seas early Saturday morning were around 4 to 6 feet and are expected to remain within that range through at least Monday night. Northerly winds over the outer waters have increased with gusts up to 25 kt by late Saturday afternoon with these gusts persisting through very early Sunday morning. Wind gusts will generally stay below 21 kt over the inner waters, but there could be isolated gusts up to 25 kt through early Sunday morning. Winds turn more offshore and weaken on Sunday before becoming northwesterly by Monday afternoon.

Seas expected to slowly build during the latter part of next week towards 6 to 9 ft, as gusty northerly winds and a fresh northerly swell impacts all waters. This will likely result in another round of marginal Small Craft Advisory conditions. /42

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Small Craft Advisory until 5 AM PDT Sunday for PZZ271>273.