From last night’s 00z run. Interesting the upper high redevelops in the “sweet spot” after Thanksgiving…supposedly.
The cold front moved through right on schedule this morning with a good burst of rain, although totals so far today aren’t all that impressive, just 1/3rd to 1/2″
Neither the rain, wind, or temperature change by themselves were impressive, but what was most impressive was the sharpness of the front. By that I mean a quick and dramatic arrival with peak gusts between 30-40 mph central/west valley and a few minutes of extremely heavy rain. A nice 5 degree temp drop was the “icing on the cake” for the weather geeks like me. We tend to have a lot of weak cold and occluded fronts around here. Notice the peak gusts were nothing special for November:
I noticed the cold front lost some of it’s “wind power” as it headed into the east side of the valley. Not many gusts even to 30 mph east of I-205. Near the Gorge part of that was probably due to the last of the east wind dying off, but even up around Happy Valley, Sandy, and Damascus it wasn’t too windy.
I have seen reference to some areas getting a “downburst” or “possible tornado” this morning. At this point it appears neither one occurred, at least according to the NWS.
What did happen is that in at least two spots (Gervais and Dallas), much stronger wind surfaced and caused damage. In both areas the wind was strong enough to damage farm buildings. Here’s the storm report from Portland NWS on the Dallas one:
0830 AM NON-TSTM WND GST 4 ESE DALLAS 44.90N 123.24W 11/07/2013 E70.00 MPH POLK OR PUBLIC BARN HEAVILY DAMAGED AND SEVERAL LARGE TREES WERE SNAPPED RESULTING IN DOWN POWERLINES. TIME IS UNKNOWN...BUT GROUND REPORTS SUGGEST BETWEEN 830 AND 910 AM...EVEN THOUGH FRONTAL PASSAGE ACCORDING TO RADAR WAS CLOSER TO 810 AM. STORM ASSESSMENT ESTIMATED 70 MPH WINDS.
Apparently no downburst or tornado because no evidence of swirling debris and/or outward pointing damage signature. Part of the damage intensity might be due to direction the wind came from. The wind gusts were southwest to west with the cold front, similar to a March 2011 event that brought a 55mph gust to PDX. That one caused 50,000 PGE power outages. We don’t see a strong west wind like that or today’s very often.
A very busy day in the weather center since we recorded our “year-end” weather special. It plays on Thanksgiving and Christmas. Then a school visit, then an all-day long food drive with the Portland Rescue Mission in the other studio.
Chief Meteorologist Mark Nelsen