9:30pm Heat Update

July 21, 2006

I would agree with those of you below talking about the warm night ahead.   I can’t believe it’s 9:45pm and the temperature at our station is still 89 on the roof!
This may be the warmest/muggiest night many of us have ever seen in Portland.  What could be more "perfect" for a warm night?  A record high temp, then thick cloud cover arrives immediately following peak heating.  Plus the dewpoint is well into the 60’s now.  So I’m forecasting 72.  Our RPM model shows about 76.  Of course the all time record is 74 at PDX, so this will be one of the warmest nights ever in the metro area. 
I dropped tomorrow’s forecast to 97, assuming that the cloud cover would be pretty persistent through midday.  If it breaks up quickly, we’ll be back to 100.  The radar looks impressive this evening, but there’s hardly any rain reaching the ground.  In fact there have been NO lightning strikes in Oregon today or this evening.  All moisture appears to be above 10,000′.
Not much cooling Sunday, then a pretty good push Monday to put us back down to 90 or so.  That should feel much more comfortable.

3:00pm Update

July 21, 2006

Wow!  Looks like even without the east wind (it never made it out of the Gorge), our light north wind is mixing down the drier & hot air.  It happened first earlier at Hillsboro, now PDX has made a 5 degree jump from 97-102 at 3pm.  Best bet is that it maxes out near 104 or 105 at PDX.  How exciting, the warmest temperature I’ve seen at PDX my career is almost here!

As you have all noticed, a thick layer of cloud cover is approaching, just in time for…tonight.  The GFS & our RPM model showed this yesterday, and apparently they are right.  It should move overhead during the nighttime hours, then head out of here early tomorrow afternoon.  So cooler tomorrow, but what about a cloudy night AFTER a 104 degree day???  Our model shows mid-upper 70’s, which has never occurred at PDX.  The record warm low is 74.  Considering how thick the cloud cover is, this could be a record breaker.  I’m glad the clouds didn’t show up midday and ruin our high temp….more later…Mark

8:00am Update

July 21, 2006

Everything appears to be in place for a VERY hot day across Western OR/WA.

1.  Offshore flow developed overnight and is stronger than I expected, almost 3 millibars Portland to The Dalles (PDX-DLS) right now.  That’s about the same as the June heat wave.  So east wind may make it close to the airport, for sure to Troutdale/Gresham/Camas.

2.  85 degrees at 6am at 1800′ on our TV tower…that’s impressive.

3.  No high clouds to interfere.

4.  If an east wind actually briefly makes it to PDX, I could see 105 or 106, otherwise 104 still looks good.

Looks like all models are latching onto upper level moisture moving overhead tonight/tomorrow.  That may do 2 things:  1.  A very warm night…maybe 70-75? and 2.  Cut down on heating tomorrow, a thick high cloud cover could keep us near or below 100 of course.

And a bonus to the heat wave…I had to get up at 6am this morning for KXL radio, so I made a coffee and went outside to water plants.  Nice and warm already.  With a warm night it sure smells good outside with plants blooming.  Kind of like a visit to Florida.  Of course the payback is the heat this afternoon.

Stay cool, and we’ll see if it IS the warmest day since 1988…Mark