“Real” Summer May Be Less Than A Week Away!

June 29, 2012

We are just 3 weeks away from the warmest temperatures of the year (the average):

From July 19th to August 13th the average high temp in Portland is 82 degrees.  After that it starts to fall off again.

Today’s high of 77 was perfectly normal, although the warm temperature along with almost totally cloudy skies was a bit strange.  We’ve got another warm night on the way too; last night it only dropped to 62 here in Portland and tonight should be similar.

Tomorrow the cold front offshore right now moves inland over us.  There is plenty of moisture to work with…precipitable water was 1.17″ on the Salem sounding this evening.  That’s much higher than normal.  Lifted Index goes below zero tomorrow afternoon with even some decent CAPE west of the Cascades too.  So the chance for convection is pretty good, but there doesn’t appear to be a big trigger for widespread thunderstorms.  It’ll be interesting to see if we do get some decent downpours.  Our RPM shows a few heavy showers/t’storms midday and into the afternoon.

After tomorrow, Sunday and Monday look quite nice, just leftover clouds through a good part of Sunday.

A bit of a change the past 48 hours; models are saying that our “real” summer will be here in about a week.  Look at the 12z ECMWF ensemble 850mb temp chart:

Notice the operational (blue) ECMWF goes above average (green line) on the 5th of July, the ensemble mean (red) slightly later.  What really adds credibility to a major change on the way?  Almost every single ensemble member (there are 51) is above average after next Friday.  And we’ve seen several runs like this now.  The ECMWF would imply 90 degree temperatures are likely by next weekend.

The 00z GFS is keeping the warm weather theme going as well.  Same story with the ensemble average going above normal next Friday (the 6th).  Notice this model too has 850mb temps up in the +15 to +20 degree range by next weekend.  Next weekend may be very summery!

This does occasionally happen; if you’ve lived here long you know that sometimes summer arrives like a “switch has suddenly been turned on”.  And this would be the time of the year for that to happen.

OR, just like in winter, models may be having trouble with the persistent pattern of cool troughs close by and will revert back to that pattern in the next 48 hours…we’ll see.

Chief Meteorologist Mark Nelsen

Historic Heat on the Great Plains

June 27, 2012

Look at all the ALL-TIME record high temps set the past two days.  Dodge City’s records go all the way back before 1880, so this would eclipse the Great Dust Bowl heatwaves in the 1930s too.  And it appears the weather pattern will not change significantly in the next week or so.  Models show a large upper-level ridge covering almost the entire USA.  This is after the warmest spring ever recorded…bad news for the whole country.  So maybe our 65-80 degree days aren’t that bad eh?

There have been hints in the past 24 hours that we might see a change after about July 6th-7th.  Especially on the 12z ECMWF.  Note the rising 850mb ensemble temps from that time onward:

But of course we’re talking 10 days away…LaLa Land as we like to say in the business.  The 00z GFS chart is a bit closer to average (the light green line) through the first 1/3 of July:

Chief Meteorologist Mark Nelsen

Funny Photo

June 27, 2012

I’ve seen slightly different versions of the same thing floating around the Internet…where is summer?  Much warmer weather MIGHT be coming right after the 4th…we’ll see.  Thanks to Michelle in Tillamook for the pic.


3rd Wettest June In Portland

June 26, 2012

The rainfall last night and then downpours this afternoon pushed our monthly rain total to 3.76″ here in Portland; that’s now the 3rd wettest. Remember the REALLY wet month? That was just two years ago!

Interesting to note that this doesn’t seem to mean too much for the rest of summer when we look back at past wet June weather.

The forecast for the next week doesn’t look so bad, except for Friday and Saturday.  A system coming through Saturday may give us actual widespread rain, I’m keeping an eye on that.  But tomorrow and the first 2-3 days of next week look perfectly reasonable for this time of year.

Chief Meteorologist Mark Nelsen

Mass Fire Evacuations This Evening In Colorado

June 26, 2012

32,000 people have been evacuated as a wildfire burns out of control on the outskirts of Colorado Springs this evening.  Here is a live stream from KUSA Television out of Denver.


By the way, Denver hit 105 again today, tying the all-time hottest temperature there for the 2nd day in a row.

2nd Coolest June in 20 Years; Cool Continues Into Early July

June 25, 2012

Hmmm, seems like I’ve posted on this subject recently…yes, that’s it.  Now I remember…another cool spring and another chilly June.  I created this chart this evening:

It shows our current PDX June temperature (5 days left) running at 60.5 degrees, eclipsed only by 2010 since the very cold June of 1991.  We haven’t cracked the top 5 coldest Junes, but it’s close.  Of more interest may be the fact that the five-year average is the lowest since the early 1960s.  It also happened to be a very chilly 5 year period in the early mid 1950s.  So maybe we were overdue. 

Clearly this has not the case across the rest of the country, wow…look at that continued warming the last 5 years:

There has been no drop in June (or summer) temps when the whole lower 48 our averaged together. 

If someone has A LOT of time (graduate student), they could try to figure out why.  Maybe the incidence of upper-troughs hanging near the West Coast in late spring has increased?  Stronger onshore flow?

I don’t see any significant change away from our cooler than average weather through next week.  Most likely we won’t see a big warmup for the 4th of July.  I have no idea if it’ll be cloudy or possibly showery, but there is no sign of a large upper-level ridge nearby through the first few days of July.  Models are in quite good agreement on this.  Here is the latest 850mb ensemble charts from the 12z ECMWF showing ensemble temps near or below average through at least July 8th:

and the 18z GFS shows ensemble temps are near or below average through July 6th:

Chief Meteorologist Mark Nelsen

Cool Weekend Ahead, June May End Cool Too

June 22, 2012

A cold upper trough sits offshore right now and pretty much stays there until Tuesday.  So get used to more cloud cover, off/on showers, and cooler than average temperatures. 

Models keep implying we get enough instability with the cooler air aloft tomorrow for a few thunderstorms.  This will be in a south-southwest flow ahead of the trough.  That’s the extent of interesting weather to look forward to in the upcoming week. 

We are heading into the deadest weather time of the year.  Rarely do we have much to talk about between late June and early October.  Occasional extreme heat or some thunderstorms west of the Cascades are about it.  I tend to blog a bit less during this time as a result; it’s a bit harder to get inspired.  That’s also the reason I prefer to take just about all my vacation time June-August too.

Beyond Tuesday, models are showing some sort of ridging for the latter half of next week.  But neither the ECMWF or GFS show this as the BIG SHIFT into our summer pattern.  Check out the 12z ECMWF ensemble chart:

and then the 00z GFS chart:

They both show brief warming the 2nd half of next week, then just average or below average 850mb temps beyond that time into the first few days of July.  So this is going to go down as another cooler and wetter than average June.  It doesn’t seem THAT bad to me, but that might be because this Spring hasn’t been nearly as bad as the previous two.  I showed this graphic last night; the number of 80 degree days from April through June. 

Last year we only had 2 through June.  This year we’ll probably end up with 11 or 12.  The big change this year is that we haven’t seen extended periods of cold and wet; it’s been broken up by occasional brief warm spells.

Chief Meteorologist Mark Nelsen