Last Post For June

June 22, 2007

SnapshotHere’s a slightly updated version of the graphic I used earlier in the week.  Remember the warmest June day (101) ever was followed the next by a 102?  What a difference for this weekend.  A cold upper-level trough moves inland by Sunday.  We should avoid the showers again tomorrow, especially since the clouds offshore are broken-scattered again this evening.  Then a cool and wet day Sunday.  Low lifted index (near zero) and some decent CAPE definitely point to thunderstorms Sunday.  Not a huge outbreak, but a cool spring-type pattern.   Brrr…
Models agree quite well on next week’s pattern.   Very similar to this week.  We get brief ridging Monday-Wednesday then ANOTHER cold trough approaches the latter half of the week.  Once again, as I mentioned last night, we may get more of a southerly upper-level flow as the low approaches.  That’s compared to the last two troughs and their west-southwest flow.  A setup like this is better for thunderstorms in our region.  Definitely good for thunder east of the Cascades late week.
I’m off on vacation for the next week and a half.  Well, at least after 9am on Sunday I will be.  I’m filling in tomorrow night and again Sunday morning on GDO.  Then I won’t be back until the 4th of July.  Enjoy the rest of the month…Mark

Cool Clouds & Missed Forecast

June 21, 2007

PhotoSeveral of you were discussing the bright clouds seen the other night over an hour AFTER sunset and one viewer emailed me asking what they were.  So I checked out the pictures too.  The one on the left was taken by Kellen Harrel here in Portland about the time I was on the air Tuesday night (10:35pm or so).  Head here to check out more pictures of the Noctilucent Clouds And here is a link from NASA that explains their Mission to Study Noctilucent Clouds
A bit strange considering the sightings of these clouds are increasing.  Hmmm, call Mulder and Scully.
Now, on to the weather…a missed forecast this morning, but no one complains when the weather is much better than expected.  On my drive home at midnight low clouds were solid from Downtown Portland all the way out to the Gorge.  Then at 4:30am when the annoying dog was barking and wanting out, I had drizzle and a light shower at my home out there.  So I wake up to sunshine and another warm day…how did that happen?!  Most likely a wave in the southwesterly flow passing overhead broke up the marine layer around sunrise.  A dying trough or front is moving through Northwest Oregon right now, but behind it there is no solid deck of marine clouds, so I think we’ll see broken skies again tomorrow.  Just a bit cloudier and a bit cooler.
No changes in the long range forecast…a cold trough and then brief ridging next week before another chilly trough moves towards us midweek.  This next one may be more interesting since the low seems to give us southerly flow ahead of it…a bit more of a thunderstorm pattern across the entire region…Time for the 11pm show…got to go…Mark

Marine Push

June 20, 2007

SnapshotA very brief post tonight because I need to catch up on some emails.
Major marine push this evening.  I noticed the North Bend to Portland pressure gradient maxed out at 8 millibars.  Now it’s back to the marine-air-dominated weather pattern.  Lots of gray and some showers/sprinkles at times.
The only major change to the forecast today and this evening was in the long range outlook.  The 18z and now the 00z GFS have completely destroyed any idea of decent ridging for 80+ temps next week.  In fact the new 00z GFS now has a deep trough nearby all of next week.  Apparently June will end cool and cloudy.  There will be some improvement Monday and Tuesday as we had this week, but then it’s downhill after that.  Enjoy the first day of summer…but remember that summer west of the Cascades doesn’t REALLY begin until AFTER the 4th of July.  Now discuss amongst yourselves..Mark

Very Brief Warm Spell

June 19, 2007

Photo2I mentioned what appeared to be a Circumzenithal Arc  in the 10pm show tonight.  It’s somewhat more rare than a halo around the sun.  Nice colors overhead today though.  Click on that link to see much more detailed info about what causes an arc such as this.
A quick jump into summer today.  I noticed there was even a very brief east wind at the west end of the Gorge this morning as the onshore flow briefly stopped.  That’s what helped us go from 67 at PDX yesterday to 83 today.  Pretty good to get a 16 degree jump in one day.  Now we level off tomorrow as onshore flow kicks in late in the day.  Weakening front offshore moves inland Thursday morning.  Latest (00z) runs show little or no moisture making it into the Western Valleys with this system.  Considering the past 10 days it’s probably safest to have a few sprinkles in the forecast, but I took them out (living dangerously apparently).  Big trough gets closer and closer and then moves into the Northwest Saturday and Sunday.  Luckily I work those days so apparently I won’t be missing any nice summer weather eh?
I see a change, a very familiar change, in the 00z long range maps tonight.  Ridging is going to stay to the east next week, keeping a new trough quite close to the close.  So I reduced the high temps to below 80 degrees next Monday and Tuesday.  Hmm…Cloudy June weather is going to continue…Mark

Briefly Warmer

June 18, 2007

SnapshotWell, apparently we will not see an early start to warm and dry summer weather this year as we did last summer.  You may remember, as shown on the left, that we went warm and dry after mid-June, and serious Fall rain didn’t arrive until right after Halloween.  It was a long & dry summer.  BUT, that was an anomaly.  This June is looking pretty darn average.  In fact the PDX temperature is running just about average for the month so far and rainfall is actually slightly BELOW normal.  We’ve just had lots of dribbles of rain, making it seem wetter.
Well, a brief break for Tuesday and Wednesday as a transient ridge of upper-level high pressure moves overhead.  That weakens the onshore flow quite a bit AND gives us much warmer air up above as well.  With strong June sunshine, temperatures rebound nicely.  Then what appears to be a very persistent upper-level trough offshore pushes closer and closer Thursday-Saturday.  That first sends in a push of marine air and clouds Thursday, possibly with showers.  Then cooler air and a better chance for showers arrives Saturday and Sunday.  So it’s back to the cloudier and cooler weather after Thursday.
Long range maps (GFS & ECMWF) show much stronger ridging beginning Monday and into next week, but they are already backing off on that, so no need to raise temps in the 7 Day much…for now.  So, I have covered my "warm weather" veggies with heat-holding plastic tunnels and applied slug bait all over the garden too.  Mark

Cool Weekend and Garden Railroads

June 15, 2007

Junk2I normally don’t promote events on my weathercast unless they are directly related to the station.  But this was too interesting to pass up.  If you’re looking for something very different to do tomorrow, June 16th, check this out:  Railroads in the Garden Summer Tour .  The Rose City Garden Railway Society allows to you come and visit 9 different model railroad layouts that are OUTSIDE in people’s gardens and yards.  I didn’t even know this hobby existed until someone from east Multnomah County emailed me.  Neat stuff, especially if you have kids.  All the details for visiting are at the link above.
Now, on to weather…it looks slightly wet this weekend, even though skies sure did clear out nicely this evening.  We have another trough approaching from the west this evening and it helps to deepen the "big trough" developing over southern British Columbia the next 24 hours.  Models continue to keep just about all rain north of the Columbia River and west of the Cascades the next 2 days, but I find that hard to believe considering the last 24 hours worth of forecast disaster.  Of course I refer to the rain that arrived overnight with almost no warning.  I’m glad it wasn’t 28 degrees…
850mb. temps aren’t quite as cold for this weekend on latest models, staying above 2-3 deg. C.  That keeps snow at timberline or above in the Cascades with any showers that develop.  I still feel Sunday morning gives us the best chance for showers out of this episode.
There is some good news in the long range maps (beyond Monday).  At least now we’re back to about average agreement in models instead of the mess we saw yesterday.  Looks like the general pattern for the next 7-10 days stays "troughy" over the Northwest and just offshore, but for 3 days or so, starting Monday afternoon, the ridge to the east over the Rockes backs up slightly farther to the west, giving us a warmup during that time.  By late next week the big trough offshore once again gets close enough to give us a much thicker marine layer.  Eventually showers should arrive as well…next weekend?  Enjoy the clouds and cool weather this weekend, you may be hoping for it as some point this summer during a heat wave!  Mark

Can’t Shake The Cool Weather

June 14, 2007

SnapshotAfter a forecast in the lower to mid 70’s today, I was surprised that most of us only made it into the upper 60’s.  And apparently it only goes downhill from there into the weekend.
First, tonight there is a nice little system moving onshore, bringing showers to the Coast and now sprinkles inland.  I see radar returns approaching McMinnville at 10:45pm.  It’s a fast moving system so it will be out of the area by midday tomorrow. 
Then a stronger trough moves in over the weekend.  This seems to be a persistent pattern for the last 2 weeks, so another cloudy and cool weekend with a good chance for showers Sunday.
Long range is a mess.  Maps are all over the place.  GFS had absolutely no ridging in the morning and midday runs (12z/18z), but no is looking a bit more similar to the ECMWF.  I took an average of the two, which gives 850mb. temps of 12 on Tuesday-Wednesday afternoon, and assumed very light onshore flow.  That’s how I ended up with a 7 Day forecast much cooler than yesterday’s, but not nearly as cool as the 12z/18z GFS.  Do you like that forecast reasoning?  If not you get to make your own 7 Day Forecast.  Now take a look at the 00z Canadian.  It would give us 60’s and showers much of next week!  As I mentioned, what a mess!  I do plan to put the little plastic tunnels back up over my "warm-season" vegetables tomorrow.  Just too much chilly weather ahead on the maps…Mark