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

Mixed and variable flying conditions in place as a cold front remains stalled over portions of western Oregon. The steadiest rainfall will continue largely to the south and southeast of KSLE with scattered to numerous rain showers elsewhere to the southeast of a line from KTMK to KSPB. MVFR/IFR cigs at most area terminals are favored to continue through Sunday morning, with a greater than 75% chance of MVFR or lower cigs and 30-50% chance of IFR or lower cigs, before conditions begin to improve from north to south as the front finally exits southward through this evening. Vis restrictions remain possible within lingering rain showers, but timing of terminal impacts is low confidence. To the north of the front (KAST, KKLS), chances for rain are lower, but fog/mist may restrict vis through the remainder of the overnight period. Variable winds continue at 5-10 kt across the region.

KPDX AND APPROACHES...IFR cigs with scattered rain showers favored (50-60% chance) to continue through 15-16z Sun, then MVFR/VFR cigs are roughly equally likely (40-50% chance of each) through the remainder of the period as rain showers linger behind the cold front. Unrestricted vis is most likely throughout the period, however brief reductions as showers pass over the terminal are expected. Timing of impacts from showers is low confidence, with a 10-30% chance of MVFR vis at any time showers are present. Winds around 5 kt with varying direction expected through the period. -36

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.