textproduct: Portland

SYNOPSIS

Dry weather continues through the today as high pressure remains over the region. Chances for precipitation return Tuesday/Wednesday, but some uncertainty remains with the exact timing and precipitation totals.

LONG TERM...Tuesday through Saturday

Models and their associated ensembles continue to support a pattern shift starting Tuesday/Wednesday as Pacific low digs across the Pacific. This looks to weaken the anchored ridge enough to finally see a substantial change in the overall forecast. While exact details remain unclear at this time, ensemble guidance is pointing towards a moderate PoP (35-60% chance). Precipitation is expected to be mainly rain, even in the Cascades as snow levels are expected to increase to 4500-5000 feet by Wednesday and greater than 6000 feet by Thursday. Precipitation totals are unclear at this time but generally follow the typical pattern with the highest totals along the Coast, Coast Range, and Cascades. Details should become clearer as time progresses and higher resolution models come into play. -19/42

AVIATION

High pressure persists over the region, supporting VFR conditions. Mostly clear skies will allow for temperatures to drop well below freezing and for widespread frost to develop, especially on metal surfaces. High clouds increase through the day as a weak system approaches the area. Tighter pressure gradients between KTTD and KDLS will lead to breezy easterly winds through the Columbia River Gorge and far east Portland Metro (KTTD) with gusts up to 25 kt. Offshore winds continue along the coast with light northerly winds across the Willamette Valley.

KPDX AND APPROACHES...VFR through the TAF period with increasing high clouds through the day. Variable winds 5 kt or less. Gusty east winds up to 25 kt expected around KTTD. -19

MARINE

A weak thermal trough along the coast will continue easterly to northeasterly winds under 10 kt across the waters through today. Winds turn more southerly tonight into Monday as a weak system moves in, however chances for widespread and frequent wind gusts exceeding 21 kt (small craft wind gusts) are only 10-20%. Seas remain around 4-5 ft at 11-12 sec through Monday night.

The next frontal system approaches the waters on Tuesday, bringing breezier southerly winds and building seas. Chances for frequent and widespread southerly wind gusts of 21 kt or greater are around 50-70%, mainly for the waters beyond 30 NM offshore. Probabilities increase for all zones to 40-50% as continued disturbances are expected to pass over the region. Exact details and timing are uncertain at this time. A west- southwesterly swell will also move in by Wednesday and build seas to 10-15 ft (60-80% chance), with a 30-40% chance for seas exceeding 15 feet as early as Wednesday evening. -19/10

PQR WATCHES/WARNINGS/ADVISORIES

OR...Cold Weather Advisory until 11 AM PST this morning for ORZ014- 105-108>110-114>118.

WA...Cold Weather Advisory until 11 AM PST this morning for WAZ204>206-208.

PZ...None.