Heat Wave Numbers

July 30, 2009

snapshot[2]Here is a list of the highest temps recorded during the heat wave


LOCATION                        TEMP        ALL-TIME RECORD
VANCOUVER                     108         105 (06/30/1942)
HOOD RIVER                    107          108 (08/18/1977)
PORTLAND AIRPORT         106          107 (08/10/1981)
SALEM                              107          108 (08/09/1981)
HILLSBORO                       106          108 (07/19/1956)
PORTLAND DNTWN            105         106 (08/10/1981)
EUGENE                            106         108 (08/09/1981)
MCMINNVILLE                  106          110 (07/10/1926) 
TROUTDALE                      105          108 (08/18/1977)

The Big Day

July 29, 2009

8:00 am:

So will today be the “big day”?  The day we tie our all-time record?  We’ll see, but I have a feeling it’s going to be close.  I’m up very early (for a bedtime after midnight at least) due to some live hits on KXL again.  Just for fun I took a drive at 7:30am to check out the temps and wind.  Microclimates can be amazing.  It was 65.1 degrees at the bottom of the little canyon I live in, then one mile up the hill (about 400′ elevation gain) the temp rose to 75.9 as I entered the “east wind zone”.  It continued rising until Women’s Forum Park overlooking Crown Pt. & Vista House.  It was exactly 80 degrees up there.  East wind is blowing maybe 15 mph with gusts to 30…just an estimate.  It appeared to be blowing some (lightly) downon the river at Rooster Rock as well.  Feels like a Hawaiian morning down there, and a beautiful sight to enjoy alone.  Apparently tourists don’t get up and going at 7am.  The last time I stopped there was December 19th as the blizzard started.  It was about 18 degrees that time with the wind gusting to 50 mph or so;  I prefer today.

There is a  real lack of weather observational data this morning.  All the non-NWS observational sites are down.  I got a message from our data provider (WSI) stating that MADIS is doing some data/server work until noon our time.  That’s apparently why there is no MesoWest info.  I think MADIS is the overall “gatherer” of non-NWS observations…or something along those lines.

11:00 am:

Things still look on track.  This is a classic summertime hot east wind day.  Looks like easterly flow has made it to most areas east of I-205.  And so far it isn’t too strong…just average 16 mph at Troutdale.  It’s perfect to mix down the warmest temps this afternoon but not get too windy.  At 11am PDX is running one degree above yesterday, but some other spots are 2-4 degrees warmer.  I think there will be sudden and dramatic jump at PDX at noon or 1pm as the drier air above (and maybe an easterly breeze) surfaces.

Some bad news for me.  I had suggested to my bosses that I should do a live shot early this summer about hyperthermia deaths in vehicles.  Basically sit in a car for 30 minutes to 1 hour and see how fast the temp rises, and more important, what effect that has on a human body.  Well, someone thinks TODAY will be the best day for that.  I was thinking more of an 80-85 degree day.  But apparently I’m locking myself in a closed car at 5pm today…with medical folks standing by.  I sweat A LOT, so it could be interesting…personally I think it’s more of a “sacrifice the weather guy to the gods” thing

10:00 pm:

Today went very fast, probably due to hanging out in a sweltering car…more on that in a minute.  So it was a big day, only our second 106 degree high in history here in PDX and Vancouver/Seattle broke their all-time high temp records (107 & 103).  But I REALLY wanted to see at least 107, preferably 108 at PDX.  We were almost in the sweet spot for easterly flow but PDX was just a little too much into the east wind zone.  A bit too much mixing, a bit too breezy, at PDX.  Too bad.  But hey, the big picture says we were only 1 degree off our forecast high;  any other time it wouldn’t matter.

As for the car thing.  It didn’t go quite as expected.  First, I had a, let’s say, “negative” reaction to the paramedics inserting an IV before the 5pm news started.  That would be partially on the makeup room floor.  But after a quick recovery I was back in the car with windows up.  It was amazingly hot, but for the first 20-25 minutes I actually felt fine.  I’ve never sweated so much in my life.  The water seemed to be just pouring off my face.  My heart rate went way up after 25 minutes, as if I was riding my bicycle hard, yet I wasn’t even moving.  It’s amazing that the human body works so hard to cool the body, but depressing that it can only last for a certain period of time.  Once you run out of sweat you go downhill very quickly.  Well I didn’t and then after the last hit I quickly got out of the car…big mistake.  I felt all clammy and let’s say I had a “negative” reaction again which involved a gurney and me wheeling into the station.  30 minutes later I felt fine, but the boss insisted I go home.  All is good now though, I’ve been drinking constantly.  The whole experience was good though in that I had no idea how quickly intense heat can take down a healthy person.

Vacation time now until the 10th of August, I’ll check in if we get good thunderstorms later next week (most likely when I’m gone!).  Otherwise I’ll be mainly out of touch somewhere on the east side of the state through midweek.

Chief Meteorologist – Mark Nelsen

Heat Wave Update

July 28, 2009


Now THIS is a heat wave!  I’ve been wondering for 18 years when we might break the all-time PDX record of 107 degrees.  We’re getting close…I see it’s 100 at 2pm, running 6 above yesterday.  Someone please tell me it’s not going to be 109 at PDX later?

A bit busy right now tracking our historic heat wave, and more important, where we are headed the next couple of days.  I’ll have some thoughts later.  But I’m guessing it may be almost time to bust out the champagne for Portland’s all-time record?  We’ll see…


Looks like we topped out at 106 degrees at PDX, the hottest temp since 1981!  Vancouver also hit 106 which makes it their all-time high temperature.  Combined with the 74 this morning tying the all-time warm low temperature, it’s truly a historic weather day in the area.  Of course the other quirky part of today’s temp is that it’s the first time we’ve had a high temperature of 106.  We’ve hit 105 a few times, and 107 three times, but that’s it…never a 106.  Weather geekery galore today.

Keep in mind that we did this with no obvious easterly flow through the Gorge or over the Cascades.  In fact the pressure gradient was very light westerly this afternoon!  That’s a very hot atmosphere.  More later…


Hmm, that was an uncomfortable TV moment around 10:25…good times.  If you didn’t see it don’t worry, not that big of a deal.  I don’t have any big thoughts about tomorrow that are much different than what I mentioned last night.  Looks like just a notch or two warmer due to the arrival of east wind across the eastern part of the Metro Area.  Maybe it’ll only reach Troutdale and Gresham, but either way the drying of the airmass plus some downslope warming should help.  I’m a bit worried that we’ll get a sudden 2-4 degrees warming…above today!  I hope not.  Seems safe to go with a all-time record-tying 107 degrees for tomorrow.

Beyond that we cool only slightly Thursday…above 100 still a good bet.  There is an obvious weak marine push Thursday night on most models.  So just above 90 the forecast for Friday.  After that models diverge a bit; the ECMWF keeps strong ridging along the West Coast, while the GFS allows an upper-level low to get close to us later in the weekend.  Both keep warm to hot weather around.  If we make it through Saturday with highs above 90, it’ll be the longest stretch of 90 degree weather in Portland’s history.

Time to go home…I may post early tomorrow morning (8am?) since I’m doing some live hits on KXL radio…Chief Meteorologist – Mark Nelsen

Surprise Thunderstorm & Evening Thoughts

July 27, 2009

Thunderstorm just east of Mt. St. Helens this evening

Thunderstorm just east of Mt. St. Helens this evening

Wow…quite an impressive thunderstorm going crazy at this hour.  Check out the cloud to ground strikes…I estimate about 30 in just 15 minutes over the “Dark Divide” area between Mt. St. Helens and Mt. Adams.  That is the divide between the Lewis and Cowlitz river drainages that runs roughly west-east between the two mountains.   You can click on the image to bring up a larger version.  Does anyone think this MIGHT cause a problem tomorrow when the thunderstorm is gone and temps in that area approach 90 degrees?  I don’t remember any significant fires in this area in the last 15 years.

Here are my thoughts at 11pm:

Amazing that we made it to 103 (all airports in the PDX area hit the same temp!) with essentially a flat gradient, or just slightly easterly.  I rode my bike past Crown Pt. around 9am there was just a light easterly breeze.  So with a slightly warmer atmosphere tomorrow, but just a flat/light easterly flow, I figure about 2 degrees warming.    That’s how I ended up with the 105.  As for tonight…whew!  This will probably be the only time I’ll hop into the kids swimming pool when I get home.  At 10pm it’s 90 degrees.  I think even during the bizarre cloudy night during the 2006 heat wave we had dropped to 88 at 10pm.    Looks like a low around 70 will probably be reasonable.

Wednesday and Thursday’s temp forecast is a bit problematic.  It’ll be scorching hot…that much is for sure.  But we get much stronger offshore flow, more like September easterly wind due to a surface high coming down into the northern Rockies.  I think it may actually turn breezy through at least the eastern half of the metro area.  With better mixing one would think it could turn even hotter than that 105.  But the upper-level heights and 850 mb temps drop a bit at the same time.  So do we turn cooler or warmer?  I’m not sure, so I just left it at 105.  I could see a situation where we don’t get much, or any,  atmospheric cooling and then the easterly breezes pick up in the afternoon.  Maybe we’ll get a surprise 107?  This could be fun (and brutal).  Even with an east wind blowing, Thursday’s atmosphere is slightly cooler again, so maybe right around 100 or just under.  Holy cow…we’re talking 4 days at/above 100 degrees if that’s the case.

Beyond Thursday:  I see the 00z GFS has backed off on the trough approaching the Coast, pretty much eliminating the thunderstorm threat and keeping us pretty warm (85 at least) through the weekend and early next week.  Now to give some of you hope, I’m headed into Eastern Oregon starting Friday for a week-long vacation.  So that’s probably when the low will make it’s move, giving us a severe thunderstorm outbreak west of the Cascades.  Stay cool!

Chief Meteorologist – Mark Nelsen

The Heat Wave is Here

July 27, 2009

It’s an early day today;  I went on KXL this morning at 7:02am (early for me) to talk heat wave numbers.  I have to admit though that I actually like heat waves.  You get some meteorological excitement, such as some offshore flow, extreme temps…etc.  But honestly, it’s sunny for the next 3-5 days…how tough of a weather forecasting day could that be?  Heat waves in the Pacific Northwest are generally just a numbers game.  So let’s talk numbers.

Looking at the 7am obs. it’s obvious the airmass is significantly warmer this morning.  I only hit 63 for a low at my home at 1,000′ in a bit of a canyon.  It feels like a Hawaiian morning.  I see it only dipped into the upper 60s in the city.  But unfortunately it’s going to get a lot hotter than Hawaii this afternoon.  I’ll have to break down use the air conditioning today.  Generally I don’t unless it gets above 95 in Portland.  Even when it gets hot in the house (86 yesterday), by dark there is a 70 degree or cooler breeze blowing down the canyon into the wide open windows and doors…very efficient and quick cooling. 

Highs:  We hit 93 yesterday with weak onshore flow, but now I see the PDX-DLS gradient has switched to slightly easterly.  So I figure about 7 degrees of warming takes us up to right around 100 degrees.   Slightly more offshore flow and a warmer atmosphere awaits for Tuesday and Wednesday, so somewhere between 100 and 105 degrees for the next 3 afternoons should be a safe bet.  Now I haven’t looked at any 12z model data yet (it’s ONLY 7:30am), but I did notice on the 00z data that we supposedly don’t get really significant surface easterly flow over us in this heat wave.  I doubt we’ll even get east wind much out of the Gorge, let alone to I-205.  Due to that I think the 105 number is high.  IF we could get a sharper thermal trough west of the Cascades, then we could sure get close (or over) to the 107 degree record. 

Lows:  This part of the forecast is probably the biggest story.  Looks like PDX might have dropped to about 67 this morning?  MOS forecasts say the city only briefly drops below 70 the next few nights as well.  Considering how warm it stayed this morning, and a hotter atmosphere/highs on the way, seems like those numbers are a bit low.  More disturbing is our RPM which has done pretty well with heat wave temps recently.  It shows lows only in the 70s the next two nights.  Since we don’t have a dry east wind coming down into the city to get rid of the low level moisture (high dewpoints), it’ll be easier to keep the nighttime temps up.  Remember that PDX’s all-time warm low is 74 degrees.  I think we’ll be in the 70-74 degree range these next two nights…yuck!  By the way, there were STILL air conditioners at a “big boxy store that sells tons of toilet paper” as of yesterday when I was there.  So I would highly recommend putting out the $125 to get yourself one.

Okay, off to a morning bike ride…not a good day for an evening “between show” ride today!

Chief Meteorologist – Mark Nelsen

Heating Up

July 24, 2009

Most 100 Degree Days Happen in July Here in Portland

Most 100 Degree Days Happen in July Here in Portland

For those of you that have been living here quite a long time, the numbers in the image probably are no surprise.  We don’t tend to have all that many 100 degree days in August, especially after the first week or so.  Mainly because it gets tougher to overcome the longer nights and their associated cooling by mid-August.  By the way, two of those August 100 degree days were from last year.

So what’s new tonight?  Not a whole lot, except it’s obvious that we get no significant offshore flow until Tuesday AM at the earliest.  That’s why I lowered the numbers in the 7 Day forecast for Sunday and Monday.  The heat wave is most definitely still on the way, but it starts a bit more slowly and may not be a historic one.  I’m still real confident that we’ll see 5-7 days at/above 90 degrees.  As for whether we get to/above 100 degrees, we’re going to need at least SOME light offshore flow.

A new twist to our little heat wave is the dewpoints/humidity.  With the upper-level low closer to us tomorrow and Sunday, we add some moisture to the airmass.  Plus with no decent onshore OR offshore flow through at least Monday, we’re not going to get much mixing.  Overnight lows are headed up between 65-70 degrees and dewpoints should jump up into at least the lower 60s.  Looks a bit sweaty Sunday and Monday at least.

Try to stay cool over the weekend!

Chief Meteorologist – Mark Nelsen

How Hot?

July 23, 2009
KPTV's 7 Day Forecast as of 7pm

KPTV's 7 Day Forecast as of 7pm

Of course that’s the big question in the 7 Day forecast isn’t it?

So while I drank my morning coffee today, I looked at some old weather maps.  There is no finer combination at 9am is there?

The maps and data I looked at were from several of our past heat waves.   Now I know several of you regulars do this sort of thing quite a bit and maybe you have numbers written down, so please correct me if you have better data.  The high temps are from PDX, the 850mb A.M. temp from SLE.

1. 107July 30th, 1965   590dm 500mb height, +23 deg. @ 850mb. (Nice surface high to the east, but not too chilly in Montana.  Closed upper level high just to our north, maybe that helped)

2. 102Aug. 9th, 1967   585dm 500mb height, +21 deg. @ 850mb (big push of cool air+high pressure moving into Montana with this one helped offshore flow)

3. 107Aug. 8th/10th, 1981   594dm 500mb height, +23 to +26 deg @ 850mb(Cooler air moving down to the east into Montana helped with offshore flow again)

4. 103July 20th, 1994   594dm 500mb height, +24.3 deg @ 850mb. (Sharp thermal trough)

So what did I notice most? 

No big surprises but some common themes:  One is that 850mb temps sure don’t have to be insanely hot, but the surface flow definitely needs to be good offshore with a sharp thermal trough to push us up around 105.  Seems like it’s all about the surface flow.  Once again, not brain surgery there.  I will admit that I expected 850mb temps of +28 to +30, but apparently that has not happened in Portland’s observational history.  I also noticed 500mb heights are not insanely high either.  I think the shape and placement of the upper level ridge is far more important.  Looks like a closed high is most “efficient” at producing heat when it’s slightly to the north of us (probably helps give more easterly flow in the mid-levels.  That was pretty obvious in the two 107 degree incidents.

Now you may notice (as of this evening) that our forecast 500mb heights and 850mb temps fall into line with all these record setting heat waves, but to get above 101 we’ll need a sharp thermal trough.  The 12z ECMWF as well as the 12z GFS showed this for at least Monday and Tuesday.  That’s why I decided to bump the 7 Day forecast up a bit.  I may end of regretting that, but in the last two big heat waves we’ve dinked around with the high temps in the days leading up to the heat.  Remember the time someone in town went with 107 or 106 and I had a 105?  I think that was 2006.  That was turning more into a “who’s got the biggest number” sort of game I think…maybe too competitive.  Those were the good old days…

Still, the big picture is an extended heat wave from Sunday through sometime later next week.  The latest ECMWF is somewhat historic if it proves correct; the 12z/18z GFS more of a “normal” 100-102 degree heat wave.  We’ll see!

Chief Meteorologist – Mark Nelsen


Hey all, look at the new tab (at the top of page) I just added with some cool cloud pictures from this evening. Here is the direct link too.


-Rob Martin