The Weekend Is Here!

September 18, 2009

snapshotAh, for some reason it seemed like a long week and as soon as I finish THIS I get to go home.  But I can’t leave the weather faithful hanging without a few tidbits to chew on for the weekend can I?

Weak front moves through tonight and tomorrow morning; nothing too exciting here.  Then assuming we get some clearing tomorrow and Sunday night we should get pretty chilly.  It’s a cooler airmass both nights, so 38-44 in the coldest spots and 45-48 in the city seems about right.

Then the big offshore flow event kicks in Sunday night.  Several things stick out now:

1.  The usual waffling of models on the details continues, but the 00z GFS is just as hot as 24 hours ago.  As I mentioned last night, it’s probably a bit too warm.  But how about that closed 594dm upper level high over us Monday and Tuesday?  Whew!  That’s almost exactly the same orientation and heights we had in the August 1981 heat wave.  Obviously at the end of September we won’t hit 107.

2.  It’s going to be stronger offshore flow Monday and Tuesday than what we’ve seen so far this season.  The WRF-GFS has about 7 millibars easterly flow from near The Dalles to PDX during the day Monday.  That supports gusts to 50 mph at the west end of the Gorge…lots of blowing/scouring sand so not a good nudie day at Rooster Rock State Park!  Just kidding (partly), but we do have a wide variety of folks who read this blog.

3.  All models have the thermal trough at or well off the Coast.  This says temps will be just about the same at the beaches as inland.  I really like the the 100 degree forecast on the WRF-GFS meteogram for North Bend.  Even Newport shows 85.  Both days temps of 85-90 should be easy to achieve.  Too bad I can’t call in sick Monday…that would be a bit obvious.

4.  I upped Tuesday’s high to 95 based on the extremely high 850mb temps and perfect offshore flow.  I think 97 is possible at PDX if the wind isn’t averaging 20 mph.  I kept Monday at 90 because the heat wave is just getting going.  However Drew and I have discussed how we tend to under-forecast the first day of east-wind type heatwaves.  Wednesday is a total guess.  00z GFS says it stays really hot, but the ECMWF had a total loss of easterly flow, which brings us back into the 80s.

5.  In general, I think this is going to be a historic late-season hot spell…what a way to end the summer!  At least it’ll be in the 40’s and lower 50s at night though.

Chief Meteorologist – Mark Nelsen

A Very Short Post

September 17, 2009

Whew…got really busy tonight answering emails, setting up school visits etc…  Before I knew it showtime was here.  So, luckily not much to talk about.

Hot weather is most definitely on the way.  Nothing significant has changed in the last 24 hours.  I’ve really tried to avoid “model-riding” the last 2-3 days.  That messed me up a bit just before the big heat wave.  Strong offshore flow begins Sunday night and continues through at least Tuesday, longer on some model runs.  00z GFS is “crazy hot”; similar to yesterday’s ECMWF.  It shows 850mb temps of 22-25 Monday through Thursday afternoons along with a 584dm  500-1000mb thickness at the peak.  It doesn’t get much hotter than that even in the summer months.  The 12z ECMWF seemed more reasonable today with a hot atmosphere Monday and Tuesday, then the ridge pushes east.  Both models still point to Tuesday as the hottest day.  I still think 95 is possible.  Also, the easterly flow goes well past the coastline, so the beaches may hit 90 in this pattern too. 

Chief Meteorologist – Mark Nelsen

Dorky Pictures

September 16, 2009

1986? Going to a big dance of some sort with Carolyn M. How about that Crockett & Tubbs inspired Tux! So cool...

So occasionally (generally about every 18 months), the bosses come up with a great idea to humiliate the news anchors & weather people.  It keeps us in line.  So in February 2008 they made me sing karaoke with Wayne and Shauna.  THEY both sounded okay, but apparently I am very tone deaf and shouldn’t sing Journey’s Open Arms alone ever again.  Now, even though it’s not a big ratings month, we have been instructed to find some geeky pictures from high school to go along with “GLEE” nights.  It’s a show that is on just before the the newscast.  I haven’t seen much of it (I’m busy just before showtime!), but it sure appears to be a good show.  So…since I want to keep my job, I brought in 3 pictures for this week.  I grew up in Mt. Angel through 7th grade, then moved to Chehalis (WA) in the 8th grade.  Good times in the 80s weren’t they?  Those of you between 35 and 45 remember well.

Circa 1982 or 1983, 8th Grade of Freshman year.  Me and my ducks...I was one weird kid!  Birds and weather, birds and weather...

1982 or 1983: In 8th Grade or Freshman year. Me and my ducks...I was one weird kid! Birds and weather, birds and weather...

Too bad about the duck though…as I recall she ended up a carcass on the back lawn one morning.  That sounds slightly callous of course, but when you grow up in the country, animals are born, hatching, or dying all the time.  Those of you that grew up in those areas  can confirm that.   I think a coyote got to Daffy, or maybe her name was Daisy, I don’t quite remember.  Then I moved on to homing pigeons after that…boy, they breed like rabbits!  But at least they didn’t poop on me as much as the ducks did every time I picked them up.  What’s up with that???

Moving on to weather…today was sure a model-perfect day wasn’t it?  Hard to believe at 10am with cloudless skies that we’d end up with a gray and rainy evening commute.  Felt like we were headed to 80 or beyond the first half of the day.  One more trough swings through here Saturday, then it’s on the THE BIG RIDGE.

No change in models for next week…I think we’re headed towards record high temps.  The 12z ECMWF was insanely hot for the last few days of September with 500mb heights above 597dm over Oregon next Tuesday/Wednesday and 850mb temps above +25.  The highest we’ve seen since 1997 is +24 at Salem.  Gut feeling is either Monday or Tuesday we get into the 94-97 degree range.  Records for Mon-Thu are 94-93-94.96

I’ll leave the forecast in the low 90s for now, but if models are still as hot by tomorrow afternoon, time to bump them up a few notches.  It sure looks likely that we’ll get 2 more 90 degree days to break out summertime record.

Chief Meteorologist – Mark Nelsen

Hot Weather Ahead

September 15, 2009

snapshotThe graph tells the story for this water year…it’s been another dry one.  In fact only 2 out of the last 10 “rainy seasons” have been wet.  We definitely seem to be in a drier than average regime so far this decade.  And not much rain in the next 7-10 days either.

Speaking of that, not a whole lot of excitement in the next 4 days with a couple weak systems moving through, so let’s move on to the more “dramatic” weather for next week.  Looks like another one of those episodes where models are in great agreement about an upcoming hot or cold spell.  This time it’s a big ridge.  00z GFS has 500 mb heights over 594dm for Monday-Tuesday next week.  ECMWF is similar, with a slight denting of the ridge around Tuesday by a passing shortwave.  The orientation and position of the ridge appears to be perfect to maximize offshore flow (all the way to the Coast and beyond!).  The new 00z GFS is at the “hot” extreme, with 850mb easterly flow for three days, and a thermal trough west of the Cascades at the surface from Sunday night to Wednesday midday.  850mb temps Monday through Wednesday PM are in the 22-24 degree range. 

For fun, I checked out some of our late season record hot spells…including hourly obs and upper-level heights…more on what I found in a few minutes.  The red numbers below are the highs at PDX.

Sept. 20/21, 1952:  96, 94 500mb heights peaked out around 590dm

Sept. 23/24, 1974: 94, 96 Heights appear to have peaked under 588dm, upper level high was directly overhead with a strong thermal trough (great offshore flow).  850mb temps somewhere between 20-25 deg. C

Sept. 27, 2003: 95 (latest 95 at PDX) Heights around 592 with the upper level high directly overhead.  Peak 850mb temps between 20-25 deg. again.

So nothing in these heat waves was significantly different from what models show for the upcoming week (minus the new 00z Canadian model).  The critical thing is that east wind has to move down into the metro area.  Just like last Saturday, once the wind decides to stay in the Gorge or go westerly temps won’t rise to 90.  The hourly obs. showed the east wind arriving each day at PDX around noon or so, just like it did last week.  Neat how each time the temp jumped from around 80 to 90-93 in just one hour, and then only rose another couple degrees after that.  Once again that’s quite similar to what happened last Friday.  Each evening it was calm again at PDX by 9-10pm, even in the multiple 90 degree day episodes.  Basically you never get a warm night from late September east wind in most of the metro area, except right around the mouth of the Gorge and probably on some of the hills too.  In fact I think it was the 1952 episode in which there were three days in the low-mid 90s, but lows were 52-55 each night! 

Chief Meteorologist – Mark Nelsen

Summer Won’t Give Up

September 14, 2009

snapshotI usually start getting emails this time of year about the changing colors on the trees.  Well the main “leaf colors” show up in mid-late October.  Seems like the 3rd week of Most of the coloring now on some trees is from drought stress or for that matter some of them just like to drop some yellow leaves early.  Alder trees are everywhere in westside forests and they really seem to look ragged after Labor Day.  It’s as if they worked so hard early in the season (they grow like weeds) they head for the dormant season early.  

You may remember how spectacular the colors were last year?  We had nice chilly nights in October, along with lots of sunshine and not too much rain.  Seems like sunny weather into October really helps the colors in general.  Of course the lack of gusty southerly wind and weeks of rain to rot the leaves probably helps too. 

Not much else to talk about.  We are definitely in the end of summer/early Fall doldrums.  I actually don’t like this part of the year.  Winter has exciting weather, Spring has some exciting weather and the promise of warmer days, Summer has heat and sometimes thunderstorms.  But early Fall?  Dead weather until the rainy season picks up closer to Halloween.  BORING.

00z GFS is holding onto the idea of a very hot ridge (especially for September) developing Sunday and Monday and continuing through a good chunk of next week.  ECMWF and Canadian are in agreement.  I like the 598dm upper level high centered over Oregon on the Canadian.  90+ weather is looking pretty likely as early as Monday.

Chief Meteorologist – Mark Nelsen

Home Weather Stations: A Discussion

September 11, 2009


Nice offshore flow today peaked out around 5 millibars from DLS to PDX.  No peak wind reports from the usual windy spot in Corbett (I’ll get on that in the next week or so), but even at TTD it peaked out at 37 mph.  I saw dust blowing up several hundred feet in the air out at Sand Island (Rooster Rock Park), so I’m guessing gusts out there were in the 40-50 mph range.  Lighter wind now will continue through tomorrow morning, then goes flat tomorrow.

Okay, let’s talk weather sensors.   Usually geeks like us put several hundred dollars into a good digital weather station.  It would be easy to spend over $1,000 for all the bells and whistles.

Which ones have you had good luck with, or were an absolute disaster?

What about web cams?  I see lots of those on some websites.

I’ll put my experience down below in the comments.

Chief Meteorologist – Mark Nelsen

Offshore Flow Kicking In…

September 10, 2009

snapshotSome image sizing issues tonight, not sure why, but now I’m getting annoyed.  Click on the image to actually take a look.  This is the anniversary of the Yacolt Burn.  Larry from the blog posted the link…lots of info there.  Imagine 370 square miles of forest burning just northeast of the Metro Area.  And that all burned in less than 2 days!  1/2″ ash fell in Portland itself, paint peeled off buildings in Yacolt with the fire only 1/2 mile away.  This was an east wind episode that drove the fire 30+ miles from north of Carson all the way to just east of Yacolt and Battle Ground.

Luckily, for this year, we just had a bunch of rain in the Cascades so fire danger isn’t all that high.  Plus logging practices are quite a bit different.  For example in a dry east wind we don’t burn slash piles as they did back then.  In general people are far more careful nowdays. 

I see the wind is beginning to blow at Larch Mtn (WA) and Three Corner Rock in the Gorge.  I took a hike up to that 2nd spot in July.  A nice view, but it did look like it sure was exposed.  Somehow I missed the RAWS station, must have been gagging on a Clif Bar at the time.  If I recall correctly that was the time I ran out of water halfway through a hike…tough.  Okay, I digress a little bit.  The easterly gradient through the Gorge should go up to 4 millibars or so, enough to get east wind to PDX by midday or early afternoon.  Assuming that happens, the 92 shouldn’t be hard to hit.  We hit 91 last year on the same day!  The 850mb temp was only 18 and tomorrow’s is forecast to be around 21-22.  So the potential is definitely there for 92-96 degrees.  Okay, out of time…need to drive home.

Chief Meteorologist – Mark Nelsen