Saturday 8am: A Few Thunderstorms Today

August 18, 2012

If you’re like me and have some things lying around the yard that shouldn’t get wet?  A little Whiskey-Tango look on the property like I have right now?  Put them away…there are showers and thunderstorms moving from south to north up the Willamette Valley this morning and anyone west of the Cascades could have a shower.  Here’s a good link to radar:

For a much better view, and to see lightning strikes, go here:  then RADAR > INTERACTIVE MAP > turn off national radar and turn on LOCAL SUPER RES, turn on GLOBAL LIGHTNING.  Then you can move all over the map.

Here are the lightning strikes in northwest Oregon as of 8am:

I’ll be at work later today.  We have an 8pm show on KPDX-TV and the usual 10pm on KPTV.

Chief Meteorologist Mark Nelsen

The Heat Wave is Over!

August 17, 2012

It’ll take awhile to cool off our homes (if you don’t have air conditioning and/or a heat pump), but we’re done with the heat now.

Much cooler ocean air is surging inland this evening.  The areas close to the low gaps in the Coast Range have been the first to cool off.  At 9pm it’s in the cool 60s everywhere inland in the western valleys between Eugene and Kelso except right in the metro area.  But even we will drop into the 60s earlier than last night.  Nature’s air conditioner is kicking in…we’ll drop a good 10-15 degrees tomorrow and a few more degrees on Sunday.  Then get used to 70s to lower 80s for highs much of next week.  It’ll be very pleasant, but quite a bit cloudier in the mornings.

Portland hit 96, 100, 97 the past three days.  That would be a 97 today.  I can almost guarantee this past week will go down as the warmest period of summer.  We had 6 days near/above 90 degrees ending today.  All long range maps have significantly cooler weather all of next week and into the last few days of August.  And we don’t get prolonged hot spells with warm nights in September; although last September was close!

Chief Meteorologist Mark Nelsen


Hot Offshore Flow Ends: Marine Push in Valley This Evening

August 16, 2012

It hit 100 in Portland today, our 2nd 100 of the season.  Most likely we won’t hit 100 again this year.  Not a guarantee, but the weather pattern looks significantly cooler for the next 7+ days starting Saturday.  In fact someone mentioned that right now we are in the warmest August on record.  Well, that’s with the hottest part of the month most likely behind us and the cooler pattern ahead.  It’s very unlikely we’re going to see that warm average temp hold up.

I also think we probably won’t hit 100 tomorrow, more like 96-98?  That’s just my “shoot from the hip” analysis.  I’ve found that without offshore (easterly) windflow it’s very tough to get out of the mid 90s once we hit the latter half of August.  Look at today; with almost perfect conditions we just barely hit 100.  It would have taken a warmer upper-level atmosphere to push us up into the 102-105 range; I mentioned that on a posting earlier this week.  There seemed to be some wishcasting going on too. 

This evening a very obvious marine push is in progress.  McMinnville is running 10 degrees cooler than at 9pm last night.  Corvallis has a west wind gusting to 24 mph. That plus a totally calm western Gorge indicates that even though the heat wave isn’t over, it sure won’t be as hot or hotter tomorrow.  When is the last time you saw a push into the Valley during a heat wave and then warmer temps the next day?  It doesn’t happen.  Thus a slightly cooler (but still hot!) day tomorrow.

Saturday and Sunday we get back to our usual marine-influenced summer weather with highs only 80-87 or so.  So this will be a 3 day heat wave; pretty typical for summertime here.

Speaking of the marine push, I spent 1pm-6pm at Cannon Beach.  A hot drive over there with no cooling until the turnoff to Saddle Mtn about 10 miles east of the coastline.  The fog/clouds thickened all afternoon on the beach; and by 4pm I said “forget this!” as I was cold in my shirt and shorts.  Then a slow warmup on the 60 miles back to the metro area. 

Chief Meteorologist Mark Nelsen

The Heat Wave is Here: 96 degree High in Portland Today

August 15, 2012

A real scorcher today with an afternoon high of 96 here in Portland.  I think this is the only time I remember having low clouds through 9am, then an afternoon high of 96!  That’s because the surface wind flow was turning from onshore to offshore during the morning hours as drier Canadian air was moving down into Eastern Washington and North Central Oregon.   The lowest 1,000′ or so this morning was still mild marine air, but that eroded away as the day went on.  I made the unfortunate (and cheap) choice of NOT using the air conditioning at home today, thinking that if PDX was only going to hit 90 or so, it would only be about 82 here (that’s common).  Well, the mixing from the gusty east wind means that I made it to 89.  It’s really hot inside right now with all the windows wide open.  I’ll crank up that AC tomorrow and Friday though!

The easterly wind hasn’t reached the lowest few hundred feet in most of the metro area, but it will tomorrow, at least east of I-5 and in the hills.  Right now east wind is gusting over 30 mph at times at Vista House.  That ensures a real scorcher tomorrow!  We’ll get even better mixing for another 4-7 degree temperature jump.  That puts most of us in the Western Valleys and Portland Metro somewhere between 99 and 104.

The record high at PDX for tomorrow is 102 and we could reach it, although I’d probably forecast 100 or 101 if I was working tonight.

There are two bright spots:

  1. Dewpoints (moisture in the air) are dropping quickly in the east wind locations so tomorrow should be  “dry heat” as they say.
  2. The heat wave will only last 3 days, since Saturday we will see some marine air work into the Valleys…if we get lucky highs will stay in the upper 80s.

Chief Meteorologist Mark Nelsen

Late Summer; Fire Smoke Time

August 14, 2012

The morning visible satellite image shows a new (and obvious) smoke plume about 40 miles SE of the Portland Metro area.  It’s a complex of small lightning-started fires from 10 days ago that must have blown up in the past 24 hours just SE of Olallie Lake on the Warm Springs Reservation.  To have a plume of smoke still going during the coolest and calmest time of the day is impressive.  Fires show up best in the early morning and evening on the visible images because of the low sun angle reflecting more light back at the satellite.

You see plenty of smoke on the morning image from other fires burning in far SE Oregon and Nevada.  Plus of course we still have generally hazy skies due to the smoke that arrived from Siberia last weekend.  It’s that time of year for hot temperatures and occasional smoky skies. 

By the way, a switch to northeast or easterly wind tomorrow afternoon will probably send that fire smoke from the Cascades down into the central Willamette Valley for a few days.

Chief Meteorologist Mark Nelsen


100 Degree Heat Again? Looks Likely

August 13, 2012

This is the warmest week of summer (as mentioned on Friday’s post), and it’s looking very likely that we’re headed for the hottest two days of summer late this week.

We reach 100 degrees about 60% of summers here in Portland, and we’ve done it once this year already.  I think it’s quite likely we will hit or exceed 100 degrees on Thursday and/or Friday.  The perfect setup is there on the maps:

  • Very warm upper-level ridge (hot air mass) moves overhead Wednesday-Friday.  The actual temperature at 5,000′ only warms 10-12 degrees from the “cooler” weather of today and tomorrow, but it’ll warm more than that down here in the lowlands as you’ll see below.  850mb temperatures are forecast at +23 to +25.  They rarely get warmer than that, even for 100 degree days.
  • On Wednesday, a strong (very Fall-like) surface high pressure slides down into the Northern Rockies and Northern Plains behind a departing upper-level trough.  It’s a shot of cool air and taste of Fall for them.  But this quickly turns surface wind offshore (easterly) later Wednesday through at least Friday evening.  This should be the strongest offshore flow we’ve seen since late Spring.
  • The inverted surface “heat low” sets up right on the coastline Thursday, which means extreme heat will spread to the Coast Thursday and possibly Friday, more likely just Thursday.
  • The combination of hot upper-level air mass, strong offshore flow, and total sunshine means we’re really going to bake.

How warm could we get Thursday or Friday?

1. Western Valleys, including Portland Metro:  98-104 degrees is definitely a possibility now.  For sure up to 98, but I think we’ll see some low-mid 100s.  I don’t think we’ll be near our 107 all-time record because upper-level heights aren’t high enough.  I’d prefer to see +25 to +26 degrees at 850mb. and 592+ heights at 500mb for that.

2. Oregon Coast:  85 guaranteed at least one day (Thursday) even on the central Coast this time.  95-100 is possible on the North Coast that day!  Not sure about Friday, warm for sure, but maybe not hot.  You know just a quick wind direction change to west or southwest and suddenly it’s 70 degrees out there.

By the way, the records for Thursday and Friday are 102 and 105 here in Portland, a bit hard to beat.  That was from a heat wave in 1977. 

I’m not working this week until Saturday, it’s comp time for some of those 12 weekend and holiday days I work when the rest of you are relaxing at home.  You know, President’s Day, Memorial Day, a snowy weekend or two in January etc…do I sound defensive about those days off?

Chief Meteorologist Mark Nelsen


Smoky Skies Over Pacific Northwest This Weekend

August 11, 2012

Saturday Morning:

This morning’s visible satellite image shows two areas of smoke converging on us…you can clearly see the smoke from fires in California across southern Oregon.  But if you look closely, note the hazy look over and above the patches of low clouds over NW Oregon and Western Washington.  Do you see it?  That is fire smoke from Asia!  Big fires have been ongoing all summer in eastern Russia, and eventually that smoke works its way around to our section of the globe.   And sure enough, when I look outside this morning, it’s quite hazy.  Here’s a better picture from the Terra satellite on Friday morning clearly showing the smoke moving in.  This picture is much higher resolution because it comes from a polar orbiting satellite just a few hundred miles above the surface.  The picture above is from a GOES satellite that is 23,000 miles away!

Cliff Mass wrote a great post (as he always does) about the smoke from Asia yesterday here:

The payoff is a reddish sunset, but we’ll get plenty of haze with our warm to hot weather this weekend.

By the way, most likely this is the peak of our summer weather since we’re moving into mid-August now.  Just about all 80s and 90s the next 7 days.  Once we get into the latter half of August (beyond this very warm period), we’ll see nighttime temperatures start to cool off and the risk for 95-100 degree heat really drops off.  So get outside and find some water; enjoy the best the Pacific Northwest has to offer during our short and warm summer!

Chief Meteorologist Mark Nelsen