The Heat Is On: April-Style

April 28, 2014

80 degree temperatures are on the way, including to the Oregon Coast!  Hard to believe after seeing snow down below 3,000′ this weekend, but it’s coming.  Models have been telling us this for almost a week; so quite a good forecast.

The Highlights This Week

  • Warmest weather so far this year
  • 80s at the Coast Wednesday, maybe for some spots Thursday too
  • 80s in the western valleys of Oregon and SW Washington Wednesday and Thursday
  • Gusty east wind tomorrow through Thursday morning in and near the Gorge.  Gusts could exceed 50 mph tomorrow night and Wednesday.

 

Take a look at the 500mb (~18,000′) chart for Thursday morning; that’s quite a ridge of high pressure centered right on the West Coast!  We haven’t seen that this spring so far.  That blocks all storminess and when it’s in this position we get surface high pressure to our east.  Thus the breezy east wind expected the next few days.  And when the ridge is very “sharp-looking” like this one, we tend to get a nice sharp trough of low pressure down at sea level along or off the coastline.  That’s why in this case the east wind will make it all the way to the beaches.

ecmwf_perfect500mb

How warm (hot) is it going to get?  Models are in excellent agreement that 850mb temps (~4,000′) will be around +16 to +17 over Salem/Portland Wednesday and Thursday.  When you combine that with maximum mixing of that air down to the surface due to the easterly wind, you get a high temperature of 85-90 degrees.  It is EXTREMELY rare to get 850mb temps above +16 in April.  In fact from 1992-2009, that’s 500+ days, there have only been 3 days that warm.  One that hit +17, and two that hit +18.  They were 86, 86, and 90 degree days here in Portland.  So will we break a record?

MarkWarm_PortlandRecords

The red columns are the records at PDX for the next 3 days, with my forecast numbers in yellow.  Wednesday is the day in 1998 when we hit 90 on the last day of the month, so no record coming that day.  I have a feeling we may break a record on Thursday though.

Enjoy the sunshine!

Chief Meteorologist Mark Nelsen