Warmest May in 17 Years

May 28, 2014

Oregon strawberries are at the farm stands already; a little earlier than normal.  That’s because the last half of spring has been warmer than normal.  You can see the above average temps along the West Coast on the 30 day temperature anomaly map:


It sure hasn’t been a “hot” May, but it has been consistently warm.  And have you noticed what else is different?  We haven’t had any long period of cool and wet weather!   30dayrainanomalyRainfall is running about average for northwest Oregon and southwest Washington, but the severe drought continues across southern Oregon and California.

Earlier tonight I calculated the monthly average temp with the numbers so far and then added in the forecast highs/lows for the next 3 days.  It appears that the average temperature will remain about 3 degrees above average here in Portland.  That’ll give us the warmest May in 17 years!


As mentioned, we’ve sure seen hotter weather in May, but most years that is then followed or preceded by cool/showery weather.  By the way, there’s a very good chance the much warmer than normal northeast Pacific waters are at least somewhat to “blame”.  That along with a lack of chilly westerly upper-level flow too.  Check out the huge warm pool from the coastline all the way out into the central Pacific. cpac_cdas1_anom__2_ It has been there for at least 6 months and probably isn’t going anywhere with El Nino developing to the south.  Another reason we will likely see warmer than average temps this summer, along with the data we’re seeing elsewhere referenced in a posting last week.

We will remain in weak upper-level troughing over the next 5-7 days, so we won’t be cloud-free and we won’t see decent offshore flow to push temps well into the 80s.  But temps will return to a few degrees above average (70s) starting Friday and continuing through most of next week.

Chief Meteorologist Mark Nelsen

A Real Soaker…For Some

May 28, 2014


I just got back from shopping at a very large boxy store (TONS of diaper wipes and toilet paper now) and all they were talking about was the changeable weather today.  As the one worker said…shorts one minute to umbrella and jacket the next.

The most intense storm of the day, at least according to the radar, belongs to a strong cell that moved southeast through Clark County.


Take a look at the radar image showing 66 dbZ echoes right over SR 503 in the Brush Prairie area…did it rain hard there???  I think so.


You can see how the heaviest rain avoided most of the official airport locations…Only Troutdale got close to 1/2″, although more is on the way there in the next 1/2 hour.

Chief Meteorologist Mark Nelsen


Lightning and Hail Today; But Summer Weather Ahead

May 28, 2014

2pm Wednesday…

Scappoose and northern Sauvie Island just got pounded with 11 lightning strikes the past hour as a strong thunderstorm moved through.  Probably a bunch of hail too!


As expected, a real active midday today as the chilly upper level trough is moving overhead.  We’re actually on the backside of it this afternoon so theoretically the action should die down.  But we’re also headed into the peak heating of the day, so through 5-6pm just about anyone could sail hail or thunder.  As of 2pm there haven’t been any other lightning strikes detected by the system we use (WSI).

Enjoy the rain and hope your garden gets a good soaking because I see little or no rain in the next 7-10 days.  Here is the ECMWF meteogram showing the mild and dry weather after today, although I think it’s a little on the warm side for parts of next week.


Chief Meteorologist Mark Nelsen