textproduct: Portland

SYNOPSIS

Scattered showers continue across the area. The next frontal system will bring another round of rain tonight into Thursday. A few more systems are expected to push across the area Friday, and again on Sunday, though drier and seasonably warmer weather is likely for Saturday. Uncertainty increases early next week, but ensembles are trending drier toward the middle of next week.

LONG TERM...Friday through Tuesday

A progressive and amplified weather pattern continues through the weekend and into early next week. Frontal system in the NE Pacific will bring periods of rain and dry weather through this long term period. Ensembles provide a little more clarity than 24-hours ago with these systems Friday through the weekend, though there still remains some uncertainty with total rainfall amounts with the frontal systems Friday and Sunday. A frontal band to the north associated with some weak to moderate IVT values (atmospheric river sub-tropical moisture) will likely push across the area on Friday. A few ensembles show potential for that band to hang up along the northern Oregon coast and parts of southwest Washington, but those numbers have been decreasing with total ensemble mean rainfall amounts trending lower.

Another warm front lifting north may clip the coast, but most ensemble members are indicating mostly dry weather for Saturday with offshore flow and warmer than normal temperatures likely. WPC 500 mb cluster analysis shows good agreement of a slightly stronger and more negatively tilted upper ridge extending north over the west coast on Saturday. Rain likely returns on Sunday, the first of February, as the ridge transitions east and offshore front pushes inland. More uncertainty into early next week, but models and their ensembles seem to be trending drier as frontal systems remain offshore and clusters showing an anomalously strong upper ridge building into the middle of next week. /DH

AVIATION

Scattered showers continue across the area as a frontal system exits the region. Mainly VFR conditions expected across the interior lowlands with low end VFR CIGs. That said, there is a 10-25% chance for cigs as low as 3000 ft for the inland terminals through 20z today, except a 5-10% chance from KSLE to KEUG. These low probabilities seem reasonable, as breezy southerly winds will maintain low-level mixing and showers will remain light. MVFR conditions expected along the coast and over the higher terrain as cloud cover remains persistent.

Still expecting light freezing rain or a light wintry mix in the Upper Hood River Valley due to lingering cold air. Slick surfaces and ice accumulation on area runways and outdoor surfaces is likely, albeit not impacting any of the TAF sites.

KPDX AND APPROACHES...Mainly VFR conditions expected through the 12z TAF period with light rain showers at times. Low chance (10-25%) of cigs as low as 3000 ft through 20z today. Southeast winds will persist around 10 kt. -19/23

MARINE

The pattern remains active through the rest of the week and into the weekend. South winds have eased a bit but gusts of 20-25 kt are still being reported with seas in the low teens. The Hazardous Seas Warning continues for the outer waters and a Small Craft Advisory for the inner waters and Columbia River Bar. One change to note is the upgrade to a Gale Warning for the outer waters starting at 4 PM this afternoon as another frontal system moves over the waters. Guidance has increased probabilities for frequent wind gusts to 40 kt late this afternoon through early tonight. The Small Craft for the inner waters and Bar transitions to a Hazardous Seas Warning at 4 PM as well with steep seas and wind gusts up to 30 kt expected.

The pattern remain active Friday and into the weekend with other disturbances keeping southerly winds in the Small Craft Advisory range and steep westerly swells continue to move through the waters. It is very likely that some form of a headline will be needed as details become clearer beyond Thursday. -19

PQR WATCHES/WARNINGS/ADVISORIES

OR...None.

WA...None.

PZ...Small Craft Advisory until 4 PM PST this afternoon for PZZ210- 251>253.

Hazardous Seas Warning from 4 PM this afternoon to 7 PM PST Thursday for PZZ210-251>253.

Hazardous Seas Warning until 4 PM PST this afternoon for PZZ271>273.

Gale Warning from 4 PM this afternoon to 7 AM PST Thursday for PZZ271>273.