Very Warm, But Probably No 90 This Afternoon

May 13, 2016

1:30pm Friday…

I was just outside and was thinking it doesn’t have the “it’s gonna hit 90 today” feel.  I came in, checked observations and sure enough, only upper 70s to around 80 in metro area at 1pm.

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Now I think a spot or two could touch 90, but I bet PDX only ends up around 87 today. That’s my 1pm armchair forecast since I didn’t work yesterday and don’t work today either.  On Wednesday I stuck with the 90 degree forecast, but mentioned on-air that was a high-end number, it could easily stay below 90.  The reasoning has been that overhead temperatures are not as warm as previous events this spring.  It was just +12 at 850mb over Salem this morning, expected to get up around +15 to +16 by afternoon.  We do have perfect offshore flow conditions

Assuming the high is 87-89, it will not be the warmest day of the season so far (that was 89) and not exactly a scorcher, even for mid-May.  Anywhere south of PDX in the valley stays in the 80s for sure as it is actually running COOLER than yesterday at this time in Aurora/Salem/Eugene.

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Tomorrow is sure going to be a refreshing temperature shock with at least a 20 degree and possibly 25 degree drop in the high temperature.  That depends on how much shower action we get.

Inbetween the hot day today and cool showers tomorrow we clearly have a decent chance for seeing some overnight lightning in spots!  All models show some development (showers and thundershowers) during the night as the upper-level low spins towards the coastline.  Nice divergent flow overhead means some good lifting motion, perfect for elevated convection unrelated to marine push going on at the surface.  HRRR implies most action west of I-5 and toward the coast.  WRF-GFS says it’s even farther west and nothing happens in the north Willamette Valley.  In previous events the model placement of precip hasn’t been so hot; so don’t get depressed if you live way out east metro like me…anyone could see a thunderstorm during the night.

Chief Meteorologist Mark Nelsen