The storms were located slightly farther north today and mesoscale models look even better for tomorrow.
I didn’t work yesterday, so it’s nice to not have to explain the mostly cloudy forecast that turned sunny, hot, and 90 degrees. But it was a tough forecast, that’s for sure. We did hit 90 at PDX today, the first of the year. I was out running errands this afternoon and can attest to the warmth. So why so warm? Well, look at the observations. The offshore flow surfaced across most of the Metro area today. Notice the easterly breezes at PDX, TTD, and HIO. And cloud cover remained to the south today.
For Tonight: The big storms should die down, but I notice our RPM shows some weak instability drifting up over us late (like 2-5am) and generates a few light showers. Then skies clear out around daybreak. If we get incredibly lucky maybe some flashes of lightning late tonight.
Tomorrow: There is good news for convection tomorrow. Looks to me like tomorrow COULD be the big day with several things lining up for a good outbreak right here in the city. It appears the offshore flow will continue until late afternoon, promising another very warm day. Then a sudden southwesterly marine surge arrives in the Metro Area in the evening at about the same time CAPE values reach 1500-2000. Lifted index of -2 to -4 along with precipitable water well above 1″ too. I think it’s the WRF-GFS that generates over 1″ of rainfall close by in the 5-10pm timeperiod. Our RPM model shows something similar except down closer to Salem. Can’t wait for the 00z data. Forecasting thunderstorms is even harder than snow in some ways, but I have a feeling someone between Salem and Longview in the valleys could get nailed tomorrow afternoon/evening.
Friday and Beyond: Our 2+ week spell of unusual warmth is going to come to an end with a big marine push pushing lots of low clouds inland Friday and the weekend. Not much chance for rain, but much more typical temps (highs 70-75) .