A Big Cooldown

July 25, 2006

A brief note tonight since I got busy working with some new software/equipment and ran out of time.

Marine air still surging inland, but high geopotential heights (notice 500mb heights) are keeping the layer fairly thin.  Same thing for tomorrow and Thursday.  So temps will bounce back to the 85-90 degree mark the next 2 days.
All models show a pretty good trough setting up offshore and then swinging through Washington in the Friday-Tuesday time period.  This is a very "early July" weather pattern, unusual for late July, but not unprecedented.  Looking at the 00z GFS, sure seems like showers could show up at some point, but for now I left them out of the forecast.  But we’ll be down about 30 degrees from last weekend!…Mark


Back to Normal Finally

July 24, 2006

A strong marine push in progress this evening.  Apparently what was supposed to be a two-day push is happening all in one night.  So today’s forecast was too low and tomorrow’s may end up being too high.

But what a weekend eh?

I read some of your comments, but I can’t read all 300!  Someone was discussing east wind at one point too.  Drew Jackson & I were discussing that today as well.  Do you realize we went through this entire heat wave with no hot east wind making it out of the Gorge?  I think that if east wind would have made it to PDX on Friday, we could have gained another 3 degrees and hit that magic 107 mark.  Also, consider that the upper level ridge was never right over us with strong offshore flow, as model runs at midweek had shown.  I believe if that had occurred, we could have hit 108 (or higher?).  Someday, but maybe I’ll be an old man…Mark


Sunday Update: Hotter, But No So Sweaty

July 23, 2006

A brief stop inside before more projects to work on outside (in the shade).

It’s funny how quickly we can get acclimated to weather changes.  I never thought a temperature of 90 at midday and a dewpoint of "only" 64 plus a breeze would be "more comfortable".  But today does feel a little bit more normal for Portland.  Here is a totally non-meteorological viewpoint…Yesterday was just a bizarre day, did you see the yellowish sun in the evening? 

So after the 70 degree dewpoints midday yesterday, now it just feels like more "normal" humid Portland weather.  Looks like a 100 degree day to me though.  +25.6 at SLE sounding this morning and no onshore flow of any consequence through this afternoon may push us up into the 100-103 range.   I see HIO is already up to 94 at noon, similar to Friday, although the humidity should slow down the temp rise just a bit.  We should get more of a normal NW wind this evening, which will bring in slightly drier air again, maybe dewpoints more like 60-64 by sunset. 

As for thunder possibility, the water vapor loop shows we are just at the western edge of the big moisture plume that covers all of eastern Oregon.  So maybe some good storms over the Cascades later?  Maybe not.  Either way tomorrow will be a very nice day…highs closer to 90 with dewpoints moving back to 60 or below.

By the way, I’m hoping to find out if the 72 degree dewpoint at PDX yesterday evening was the highest ever recorded here.  I’ve never seen it above 68 in my 15 years forecasting in the metro area…Mark


Sweaty Saturday Update

July 22, 2006

Would we all agree we’ve had enough of this?

How about a nice sunny, DRY, 90 degree day?  Wouldn’t that be a pleasure?

The 11am observation shows that PDX tied the all time low temperature record of 74 degrees.  You just survived the warmest night in Portland since World War II!  Add the humidity around and it feels like Florida or Hawaii today.  I notice that it never dropped below 85 degrees all night at 1,900′ on the KPTV Tower.  And when was the last time you heard about a LOW temperature of 70 at Timberline Lodge? Can you imagine paying all that money, and then sitting there all night sweating in a hot old building?  Not the best night for a fireplace room.

Today’s high is just a matter of what time the clouds disappear.  Current movement tells me they won’t move past us until 4pm or so.  It may be tough to get much above 90.

And you know it’s bad when I say "at least it’ll get down into the 60’s tonight".   If we’re lucky, maybe some evening lightning activity over the Cascades too…Mark


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


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