For the first time since Saturday we’re seeing a mellow evening in the metro area with respect to weather. A chance for meteorologists to enjoy their dinner without a tornado warning showing up (twice).
It’s been a fun or crazy or annoying three days; depending on your viewpoint.
First, on Sunday we saw thunderstorms pop up quite late in the day. One produced a tornado near Cornelius Pass, then as it passed through Vancouver a funnel cloud was seen by many; but no touchdown in this case. The NWS issued two separate tornado warnings for that storm
That tornado was the 2nd we’ve seen in our viewing area for 2019. Remember the other was in NE Portland on July 1st. Once again it was a very weak tornado.
The stats include all counties west of the Cascades from Centralia/Chehalis down to Lane county (Eugene). Notice this tornado comes right during the autumn “tornado season” in our area. Very loosely defined, but you get the idea. There’s one other “season” in our area…May and June. Still, twisters are rare in the Pacific Northwest.
That was Sunday, then yesterday lots more showers popped up in the afternoon. There were two spots with unusually heavy downpours; east side of Hillsboro and Salmon Creek area in Clark County. Check out these totals! Most of these stations picked up all that rain within 2 hours (or less!). I checked one home weather station near Westview High School: 1.88″ in one hour. Amazing.
You might be wondering about the timing of the big downpours; why not in the wet season? It’s because warmer air can hold far more moisture than a chilly winter airmass. So when it rains around here in the warm season it CAN really dump if the weather pattern is right. In fact when I think of our big street flooding issues the past 20 years, typically it has been between May and October.
Today was day #3 with thunderstorms. It did get quite intense during the early afternoon. I see Lake Oswego picked up .80″ around 2pm. As showers died down after 4pm in the metro area, the main lifting seemed to move south. There were dozens of lightning strikes in the mid Willamette Valley. Salem you had quite a storm during the evening commute. In just a 30 minute period ending around 5pm, lightning detection picked up 44 cloud-ground strikes around Salem
The airport at Salem picked up .96″ in about 90 minutes. Finally at 6:45pm I see most of the thunderstorms have dissipated. It appears the official Portland observing location at the airport has avoided the big storms/downpours through these three days. Still, we’re above average for rain this month.
A very brief look ahead says fall weather is here to stay. There’s no sign of a significant warm & dry spell through at least the middle of NEXT week. Here are the ECMWF ensemble hi/low temps for Portland the next two weeks (ignore the last day)
and ensemble rain forecast. Good chance we get into the downpours/thunder action again this coming Sunday/Monday. Maybe a bit drier around 20th or so, but then we’ll be deeper into the fall season.
It’s quite possible that “summer ended” on September 6th this year. We may not see any long stretches of upper 70s and 80s again.
By the way, a quick glimpse of Mt. Hood this evening shows snow stuck down to around 9,000′ on the mountain during our cool/wet spell
Chief Meteorologist Mark Nelsen