ECMWF Monthly Maps & Warm Nights

July 16, 2015

7:30pm Thursday…

I just took a look at last night’s monthly run of the ECMWF.  It is run twice a week and as you know I regularly post the maps in the wintertime.  Not so much in the summer because anomalies aren’t as great and patterns don’t stick out as well.  That said, this time it seems we can pick out some useful info.  Remember it’s only one model though.

Here are the 4 weekly maps; 500mb height anomaly averaged for each week

Week 1:  Cool troughing next week, especially Wednesday and beyond.  After brief hot weather this weekend temps should return to normal or a bit below through the weekend of the 26th

500za_week1_bg_NA

Week 2:  More troughing, although not as intense through the first day or two of August

500za_week2_bg_NA

Week 3:  As August begins, quite a change.  It’s not so obvious on these maps, but heights are a bit above normal.  More on that in a minute

500za_week3_bg_NA

Week 4:  Ridging returns to it’s preferred spot the past 18 months or so…looks hot.

500za_week4_bg_NA

Now these maps are the ensemble average, not the actual control run.  I took a look at the operational run and it’s quite cool right through about the 2nd of August.  Here’s a look at late next week.  Of course a week or so ago it looked like this for THIS COMING WEEKEND.  Obviously the trough was forecast too far west and ended up well inland instead.

ecmwf_next weekend

Take a look at the operational run for a few days into August.  Looks familiar doesn’t it?

ecmw_operational_aug6

This operational run has hot ridging (heights 588 dm or above) through the entire first half of August (after the 2nd).  That plus the ensembles looking much warmer than normal imply that, after a mild 2nd half of July, the first half of August could be very warm.

Again, remember it’s one model only.  But something to watch.  I am pretty confident the last 10 days of July will be real reasonable around here with no heat wave in sight!

Last night was our 25th night at/above 60 degrees in Portland this year.  Technically it is the 25th calendar day in which the low temperature didn’t drop below 60, but you get the idea.

That means we are already, on the 16th of July, halfway to last year’s “warm nights” record.

MarkHotNights_60DegreeLows

Here’s a look at the progression of 60+ nights since the Airport weather station was established around 1940…we’re heading into unprecedented territory this summer, especially if we get that hot weather in August:

Capture

I did a posting about this last September, you can find it here.

It sure does appear that the warmer than normal east Pacific (the blob) is having its way with our overnight temperatures again this summer.  Cliff Mass up at the UW just blogged about this yesterday in another excellent article.

Chief Meteorologist Mark Nelsen