textproduct: Portland

SYNOPSIS

A frontal system stalled over much of western Oregon will continue to bring widespread rainfall through Sunday, before more showery weather with welcome Cascade snow lingers into Monday night. Drier weather returns Tuesday through Thursday before rain chances increase again late in the week.

LONG TERM...Tuesday through Saturday

There is strong consensus that dry weather will return to the region from Tuesday through much of Thursday as weak ridging builds aloft. An area of low pressure favored to track into northern California Tuesday into Wednesday may bring light precipitation to the central Oregon Cascades and foothills in Lane and Linn Counties, but chances are only 15-25%. Long-range ensembles then favor a return to a cooler, wetter, and more active pattern Thursday night into next weekend as upper-level troughing is reestablished over the Pacific Northwest. The details and timing of this pattern change remain relatively lower confidence, but rain and mountain snow chances look to increase dramatically late in the workweek. -36

AVIATION

Currently, there are mixed and variable flight conditions across the air space, thanks to a stalled/slow moving cold front over western Oregon. Expect conditions trend more towards MVFR/IFR as rain is expected to continue through the majority of the TAF period. Rain is expected to impact areas south of KKLS for inland locations and south of KAST for coastal locations. For locations north of the front (KAST, KKLS), chances for rain are lower, but fog/mist may restrict vis through the remainder of the overnight period.

Overall, expect MVFR conditions to become the dominant flight conditions over the next few hours with a 15-20% chance for intermittent IFR/LIFR conditions across the airspace as well. Conditions are expected to generally improve towards the very end of the TAF period as the stalled front finally moves out of the region. Variable winds continue at 5-10 kt across the region.

KPDX AND APPROACHES...Mixture of VFR and MVFR conditions expected over the next few hours, with MVFR flight conditions expected to become dominant around 18Z Sunday. Rain is also expected to persist along with a 20% chance for intermittent IFR conditions through the TAF period. Conditions are expected to improve towards the end of the TAF period. Variable winds continue at 5-10 kt. /42

MARINE

Buoy observations show seas and winds have rapidly fallen behind the passing frontal boundary early this morning, and the Small Craft Advisory in place across the waters has therefore been cancelled. Seas of 7-9 ft at 12 seconds with variable winds near 5 kt are expected through this evening, but a 5-10% chance seas occasionally rise above 10 ft may pose a marginal hazard to small craft. When the cold front stalled over the central and southern Oregon coast finally exits southward, a westerly swell will again rise to 10-11 ft at 12-14 seconds from this evening through early Tuesday morning, with another Small Craft Advisory in effect from 7 PM today through 4 AM Tuesday across the coastal waters, and from 1 AM Monday through 1 AM Tuesday for the Columbia River Bar. Ebb currents at the mouth of the Columbia are fairly weak through midweek, generally 1-4 kt at peak tide, but could still act to steepen seas locally at the bar.

High pressure returns to the region midweek, with tranquil weather expected from Tuesday through Thursday. Long-range guidance continues to favor a return to more active and impactful marine weather Thursday night into next weekend as troughing is reestablished over the Pacific Northwest, but the details remain low confidence at this point. -36

PQR WATCHES/WARNINGS/ADVISORIES

OR...None. WA...None. PZ...Small Craft Advisory from 1 AM Monday to 1 AM PST Tuesday for PZZ210.

Small Craft Advisory from 7 PM this evening to 4 AM PST Tuesday for PZZ251>253-271>273.