Things are getting weird this evening…I came in to work today, looked at the maps and thought “that looks like late October or November!”. Why? Models were showing a relatively deep surface low pressure center scooting up the coastline quickly right after daybreak Saturday. As a precaution, the NWS issued a High Wind Watch for the coastline. Now evening models are quite similar.
Here are the highlights in case you don’t care about the meteorological info:
- Unusually strong wind is POSSIBLE on the central/north coastline of Oregon early Saturday morning. Gusts 50-70 mph are possible. That’s not tent camping weather!
- In the western valleys, including the I-5 corridor (Salem/Portland/Longview), we could see southerly wind gusts in the 35-50 mph range Saturday morning. (7-11am)
- With leaves on trees, this could cause some significant damage. Wind gusts just 40 mph would bring us lots of power outages this time of year.
- The highest wind gust ever observed at PDX in the month of August is just 39 mph. That was a southerly wind gust too.
- If the surface low ends up weaker or takes a different track, winds will be much lighter. We have two more model runs (tomorrow morning and tomorrow evening) before the event. That will give us a better handle on what’s going to happen.
- Unrelated, but of interest to you…IT’S GOING TO BE WET IN OUR AREA TOMORROW. I am working on a project outside and have a bunch of tools/nails etc…lying around. Get things covered or inside by sunrise!
In my entire career (24 years in Portland), I’ve never seen the NWS issue a High Wind Watch for anywhere west of the Cascades in the summer. That alone isn’t all that shocking, but it’s backed up with several models showing the same setup for Saturday morning. Check out the 8am image from the WRF-GFS (UW model):
This model and others are showing 9-12 millibars southerly gradient from Eugene to Olympia. That’s a big number even in winter. And this time of year the warm weather allows good mixing of stronger winds above. The WRF-GFS shows 70-75 kts at 850mb. Unheard of in August! Our RPM is quite strong with the wind as well: Here’s a wind gust forecast:
Over the past few winters I’ve noticed these speeds tend to run a bit high vs. reality. Still, this shows gusts 40+ mph in the valleys and 60-70 along the coast SOUTH OF THE LOW. Note that if our RPM (or the WRF-GFS) is correct, areas up around Astoria would stay mainly calm.
More tomorrow on the wind…
As for tomorrow’s weather, we’ve made a dramatic change in the forecast since radar, HRRR model, RPM, & WRF-GFS all show the rain band about 50 miles farther east. That puts measurable rain overhead for the first time in about two weeks. Here’s the HRRR forecast through 11am:
and RPM through Sunday afternoon is looking more pathetic…that’s too bad:
The WRF-GFS is now only showing about .50″ in the valleys too.
Chief Meteorologist Mark Nelsen