textproduct: Portland

SYNOPSIS

Active weather continues with valley rain and high mountain snow through the middle of next week. Our focus remains on a fairly robust frontal system and atmospheric river impacting the region today through Tuesday which is slated to bring additional widespread rainfall and low chances (5-10%) for river flooding. After lingering shower chances during the mid to late week period, the pattern trends drier towards next weekend.

LONG TERM...Wednesday through Saturday

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 for rainfall at times (40-60%) through Thursday and Friday of next week, the trend among ensembles models systems is towards calmer/drier weather for the start of next weekend. During this mid to late week period, temperatures look to hold near seasonal norms for late February. Beyond Saturday model uncertainty begins to increase substantial in regards to the progression of the upper-level pattern. -99/36

AVIATION

A front continues to move through the airspace, bringing MVFR conditions and occasional heavy rain. This stratiform rain has begun to transition to post-frontal showers, bringing a mixed bag of MVFR/VFR conditions (around a 40-50% chance of MVFR) at most terminals through most of the TAF period. Best chances for VFR conditions will be between 06-12Z Monday (60-70% chance of VFR). Despite somewhat favorable probabilities for VFR conditions, there is low confidence in these chances as stratiform rain may return around 09-12Z Monday, bringing increased chances of MVFR conditions.

As for winds, breezy east to southeast winds through the Columbia Gorge will decrease through today, with increased wind gusts at KTTD persisting a bit longer and expected to end around 12Z Monday.

KPDX AND APPROACHES...Currently MVFR as stratiform rain lowers CIGs and VIS. This stratiform rain has begun to transition to post-frontal showers, resulting in a mixed bag of MVFR/VFR conditions expected through most of the TAF period. While looking primarily VFR through at least 06Z Monday, heavier rain showers could briefly drag VIS down to 5-6SM. Southeasterly winds just above 10 kt continue this morning, but will gradually ease and shift more southerly around 06-12Z Monday. ~12

MARINE

Seas have peaked this morning with Buoy 29 and Buoy 50 reporting wave heights in the 17-20 feet range at 12-13 seconds. Winds have begun to trend lower with southerly gusts generally in the 30-35 knot range. Once we get into the midday and afternoon hours today, confidence is high conditions will begin to improve albeit slowly when it comes to wave heights. The hazardous seas warning will continue into early Monday morning after which point we'll likely need to transition to a Small Craft Advisory. Conditions continue to improve headed into the middle of the week with a fairly benignhupper-level pattern allowing seas bottom out around 5-7 feet Wednesday into Thursday. Then on Friday the arrival of a WSW swell may push seas above 10-12 feet. -99

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Hazardous Seas Warning until 4 AM PST Monday for PZZ210-251>253- 271>273.