Marine Weather and Tide Forecast for Glasgow, OR

.AVIATION (06Z TAFs)...

Expecting a mainly VFR TAF cycle over the next 24 hours. There is one question about patchy low clouds (MVFR) around the coast and Roseburg overnight, but given the lack of moisture and that guidance is leaning towards VFR, have kept this out of the TAF. Will monitor this and update accordingly. Otherwise, high clouds will push into the region Wednesday afternoon, followed by some mid level clouds moving onshore Wednesday evening.

PREV DISCUSSION
/Issued 315 PM PDT Tue May 20 2025/

DISCUSSION...There may be some showers and thunderstorms on Monday, but this upcoming weekend looks to be a very good time to be outdoors.

As weather impacts go, those in our area during the next week look to be relatively minor. They include coastal low clouds (mainly during the night and mornings) Wednesday night through Friday night and Sunday night into Tuesday morning), a slight chance of showers for our northern tier (mainly Coos and northern Douglas counties) late Wednesday night into Thursday morning, weak instability for a slight chance of showers and thunderstorms Friday afternoon and evening for Lake County and the Warner Mountains of northeast Modoc County, above normal temperatures inland for the holiday weekend, and a broad trough on Monday/Memorial Day (lingering on the far east side Tuesday) that could be accompanied by sufficient moisture and instability for a slight chance of showers and late day thunderstorms. A few ensemble members are a little faster with the trough arrival, which could open the door to a few showers near Crater Lake late in the day on Sunday. But, a mere increase in evening clouds is much more likely. A sizable minority of ensemble solutions, and the operational GFS are just a bit slower, which could bring the highest probability of a modest risk of showers or a few thunderstorms for Monday morning, ahead of peak heating. Thus, limiting the extent of activity.

First, high pressure will briefly build in on Wednesday with early morning low clouds for southern Douglas County. Warming and drying inland will send temperatures to several degrees above normal.

The weak trough Wednesday night into Thursday will send light showers mainly to western Washington and northwest Oregon. A slightly stronger trough will follow for Friday. With both troughs, the most widespread effect will be slight cooling, sending temperatures back to around normal. But, there could be just enough moisture and instability on Friday to produce the aforementioned far east side late day convective activity.

The coast will remain typically cool with onshore flow for the weekend. But, highs in the lower 70s to lower 80s will be several degrees above normal inland.

We will be paying close attention for better model agreement as we draw closer to Monday and Tuesday. For now, a wash out, or scattered to numerous thunderstorm activity is not at all supported by the data. But, an isolated risk is shown by a sizable minority of ensemble members.

MARINE
Updated 200 PM Tuesday, May 20, 2025
North winds have been increasing today and will be strongest south of Cape Blanco.
North winds are expected to persist into Wednesday evening, then will diminish Wednesday night as a weak upper trough approaches weakening the thermal trough. Steep west-northwest swell will remain over all waters into early this evening, and then steep seas will remain south of Cape Blanco through Wednesday evening. Light to moderate north winds are expected Wednesday night into the end of the week, but winds and seas are expected to remain below small craft.

-Hermansen

MFR WATCHES/WARNINGS/ADVISORIES
OR
CA
None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT Wednesday for PZZ356-376.