textproduct: Portland

SYNOPSIS

Active weather continues with valley rain and high mountain snow through midweek. A nearby frontal boundary and associated atmospheric river will bring periods of rain, with increasing confidence that the highest rainfall totals will occur south of Lane County and therefore decreasing chances for river flooding locally. Low chances for rain linger but decrease late this week into next weekend.

LONG TERM...Wednesday through Sunday

As the trough finally ejects eastward by midweek, a more zonal pattern is favored to develop through the long term period. While the potential for a shortwave arriving from the northwest maintains moderate chances (40-60%) for rainfall at times through Thursday and Friday, ensemble guidance is trending toward drier weather for next weekend. During this mid to late week period, temperatures look to hold near seasonal norms for late February. -99/36

AVIATION

Radar imagery as of late Sunday evening depicts widespread rain as a frontal system moves into the area. So far, CIGs remain predominately VFR with some intermittent drops to IFR/MVFR. However, as the system progresses through, will see CIGs fall to predominately MVFR across all terminals after 12z Mon. Rain will continue throughout the entire TAF period as the front stalls over the region. CIGs continue to fall to low-end MVFR (1-2 kft) after 18z Mon, with a 20-40% chance of IFR CIGs at any given hour through the end of the TAF period. Periods of moderate to heavy rain may also result in brief VIS reductions to 3-5 SM. Winds generally southerly tonight, except for breezy easterly winds in the far eastern Portland Metro. After 18-21z Mon, a low pressure system coming in from the south will turn winds more easterly along the coast and north-northeasterly across the Willamette Valley.

KPDX AND APPROACHES...VFR conditions through 12z Mon, then trending predominately MVFR CIGs/VIS after 12-15z Mon as a frontal system moves in and brings rain. 15-25% chance for IFR CIGs or lower from 18z Mon through the end of the TAF period. East-southeasterly winds continue through 12z Mon, then winds weaken and become variable throughout the day as pressure gradients ease. -10

MARINE

Seas remain above 15 ft this afternoon, with Buoy 89 recently reporting seas at 18 to 19 ft and Buoy 29 and 50 reporting seas at 16 to 17 ft. Seas peaked early today, so expect wave heights to ease overnight and into Monday. Winds also peaked earlier today and will weaken overnight into Monday, with recent observations of wind gusts 25 to 30 kt over the waters. The Hazardous Seas Warning will continue until 7 PM Monday, then transition to a Small Craft Advisory which will be in effect until 10 AM Tuesday. Conditions continue to improve headed into the middle of the week, with a fairly benign pattern allowing seas to ease to 5 to 7 ft by Wednesday. Friday, a fresh WSW swell may push seas above 10 feet. ~12

PQR WATCHES/WARNINGS/ADVISORIES

OR...None.

WA...None.

PZ...Hazardous Seas Warning until 7 PM PST Monday for PZZ210- 251>253-271>273.

Small Craft Advisory from 7 PM Monday to 10 AM PST Tuesday for PZZ210-251>253-271>273.