Marine Weather and Tide Forecast for Cascade Locks, OR

SHORT TERM
Now through Wednesday...This evening fairly quiet conditions prevail across the Pacific Northwest as a weak positively tilted ridge overhead shifts east of the Cascades leading to mostly clear skies. However, tonight into early Tuesday morning we are anticipating a change to somewhat wetter weather thanks to a weak shortwave trough moving into region accompanied by a surface front. Ensemble and deterministic models continues show rather minimal QPF with this system which is disappointing given how dry April has been compared to normal: we could use the rain. Expect generally 0.1-0.3" of rain for the Coast range/Cascades, 0.1-0.2" in the Cowlitz Valley down through the Portland Metro, and 0.03-0.1" across the rest of the Willamette Valley. Overall, the NBM shows a roughly 30-50% chance to see a wetting rain (>0.25") for the higher elevations of the north Oregon Coast range/Willapa Hills and the southwest Washington Cascades on Tuesday. For the Willamette Valley these probabilities are less than 5% during the same time period, so confidence is high rainfall amounts will stay on the lighter side for this event. Lingering showers behind the main frontal band in the morning gradually taper off by Tuesday evening. Then on Wednesday dry weather and a warming trend begins thanks to another ridge of high pressure building overhead. Confidence is high this next ridge of high pressure will lead to daytime temperatures rising into the upper 60s to near 70s for the interior lowlands Wednesday afternoon.

LONG TERM
Wednesday Night through Monday...Moving forward the latest guidance continues to suggest Thursday will be the hottest day of the week as the axis of the now amplified upper- level ridge passes overhead. The NBM is still indicating an 80-90%+ probability to reach 80 degrees in the Portland Metro and a 40-80% chance across the rest of the interior valley locations. That said, coastal locations likely remain notably cooler comparatively due to the inland movement of a near surface thermal trough allowing westerly marine influence to hold temperatures in the 60s. The period of warm weather will be relatively short lived as WPC ensemble clusters continue to show good agreement in the broader ridge feature shifting east by Friday and opening the door for the next upper level trough approaching the region. This brings another round of cooler and wetter weather to the area Friday through the weekend. Most deterministic guidance and a fair number of their respective ensemble systems do show a transitory ridge passing overhead late Sunday into Monday which would lead to a trend back to drier conditions. -Schuldt/CB

AVIATION
VFR flying conditions continue inland this evening ahead of an approaching trough, which will bring light rain showers from northwest to southeast tonight into Tuesday morning.
VFR cigs will trend to MVFR levels at 2-3 kft as rain begins by 11-12Z Tue at Portland-area terminals and 14-15Z Tue south along the Willamette Valley. MVFR cigs will likely linger after rainfall ends by 15-18Z Tue, with the highest confidence in cigs near 2 kft will extend through Tuesday morning. Periods of MVFR vis within rain are unlikely (10-20% chances), but cannot be ruled out through early Tuesday morning. Cigs will lift back to VFR by 21-24Z Tue. Light and variable winds tonight will turn out of the south to southwest at less than 5 kt by 09-12Z Tue, then turn out of the west to northwest at around 5 kt after 21-24Z Tue.

Along the coast, VFR/MVFR conditions will deteriorate quickly by 08-10Z Tue as rain begins and cigs fall to IFR levels. MVFR vis during rain is expected (50-60% chance) by 10-12Z Tue, with further restriction to IFR within lingering haze/mist at ONP through much of Tuesday morning. Cigs may lift back to VFR earlier at AST, especially after 21-24Z Tue, while persistent IFR or low-end MVFR is favored at ONP. South to southwest winds of 5 kt or less this evening will turn out of the southwest at 4-8 kt during rain showers, before increasing to 6-10 kt out of the northwest after 21-24Z Tue.

PDX AND APPROACHES...VFR flying conditions persist into tonight, with light rain and MVFR cigs beginning by 10-12Z Tue as a weak trough arrives from the northwest. MVFR cigs are most likely (70-80% chances) from 15-19Z Tue. Brief periods of MVFR cigs are possible during rain showers, most likely in the hours around sunrise, but chances are low (about 20%). There are also low (10-20%) chances for periods of IFR cigs similarly in the hours after sunrise given abundant low-level moisture. Conditions will otherwise improve to VFR by 21-24Z Tue. Light and variable winds overnight will increase out of the south at around 5 kt as rain showers begin, then turn out of the northwest by 21Z Tue. -Picard

MARINE
High pressure over the northeast Pacific continues to shift inland, supporting benign conditions much of the work week. Expect seas around 4 to 7 feet and mostly northwesterly winds at or below 10 kt with gusts 15 kt or less.

A short Small Craft Advisory for the Columbia River Bar has been issued for steep ebb chop, which will come to end by 9 AM Tue. A peak ebb current of 7.36 kt is expected at 6:22 AM Tue, yielding choppy seas around 9 feet from 3-9 AM Tue. -Hall/Batz

PQR WATCHES/WARNINGS/ADVISORIES

OR...None.
WA...None.
PZ...Small Craft Advisory from 3 AM to 9 AM PDT Tuesday for PZZ210.