Wind & Cold

February 10, 2006

Another exciting Friday now with good weather and good shows on TV (BSG of course).

Very impressive downslope windstorm is slowly waning tonight.  Rumor says there were some spots with gusts near 70 mph in Camas.  I know it hit 65 mph at the top of the West Hills.  Peak gust at PDX was 56 mph, strongest since the January 2000 windstorm.

A quiet weekend (and Monday) in store for us.

Now, what everyone wants to know…what about next week?

Well, I just adjusted my 7 Day based on the 00z Canadian, 00z GFS, and 00z ETA.  Of course as mentioned (frequently) the GFS is horrible at this stuff beyond 7 days, but now we’re watching the 4-6 day period and all the models have some sort of northerly flow developing.  Looks like a sharp, but not too wet, cold front moves through Monday night.  We are left with a cold & mainly dry airmass Tuesday and Wednesday.  00z GFS & Canadian give us a good blast of arctic air the end of next week.  We’ll see about that, but it seems prudent to lower temps quite a bit starting Tuesday.  As for snow, I still don’t see a good setup, unless we get some sort of development offshore (which sometimes happens with only a few days notice).  This could just end up being a late season cold & dry blast.  Also, this time of year, even if we drop to 15 in the outlying areas at night, temperatures still make it up to 40 during the day because of the stronger sunshine and longer days.

Should be interesting to watch though eh?  Have a good weekend and enjoy the last of the mild weather for awhile…Now discuss amongst yourselves.

More Wind Ahead

February 9, 2006

We are in the middle of a minor "downslope windstorm" tonight.  Strong Canadian high pressure is moving down out of Alberta.  It’s not excessively cold, but it’s dry and covers a huge area.  Plus the easterly flow is so deep that strong winds are going right up and over the Cascades instead of just through the Gorge.  In this situation wind is as strong or even stronger out over the valley and metro area than in the Columbia River Gorge.  I notice at 8pm the wind is gusting over 40 mph at Vancouver and Portland, but only about 35 in the west end of the Gorge at Rooster Rock.  PDX-DLS gradients are rapidly increasing tonight (9mb around 9pm) and should peak out around 12 mb by daybreak.  So widespread easterly gusts 45-50 in town are likely through midday Friday before things die down.  Eastern Clark County (specifically Battleground & Hockinson) tend to get hit hard in this setup so I expect a few gusts to 60 mph there.

The NWS has a high wind warning out for the metro area and western Gorge.  I think those Clark county spots may verify with higher gusts, but the Gorge definitely won’t get that strong.  They really get nailed during those long spells of cold temps and continuous east wind, not in this pattern

Much calmer again this weekend and Monday.

Finally (at least in my opinion) models seem to be settling down some for the Tuesday-Thursday period.  No model after 12z this morning has shown arctic air moving south, just cooler temps and some moisture.  The 12z ECMWF, 00z GEM, 00z GFS all try to dig more energy offshore and close off a low the middle of next week.  That would give us SOME wet weather but no snow levels below 1500′ or so.  Of course the 00z GFS has much colder air JUST BEYOND the 7 day forecast.  Notice how it does that all winter?  What is it with that model?  So for now I’m keeping the 7 Day forecast pretty tame.

Very Windy Days Ahead

February 8, 2006

Well, well, well, sorry about that Trace-.08" this morning.  Apparently it really set a person or two off didn’t it?  As long as those nasty comments don’t become a regular occurrence, I’ll leave the comments open.  I just love the DELETE button in this case!

So first in the short term:

We are going to be quite close to getting a "downslope" windstorm for tomorrow night and Friday.  A very strong dome of Canadian high pressure slides south into the Western U.S.  The air is not really all that cold, but it all comes shooting over the Cascades AND through the passes/Gorge.  Peak pressure gradients across the Cascades (PDX-DLS) appear to be 10-13 millibars by early Friday morning.  A 12 millibar gradient with this setup has, in the last 2 winters, produced easterly wind gusts to 60mph around Battleground/Hockinson and gusts to 45-50 mph in the hills around Portland.  Often these areas get stronger wind than the Gorge since the wind is really coming right down off of the Cascade foothills.  Then the offshore flow dies down pretty dramatically Friday night.  So it’s going to be a 2-day windy/sunny period.

Now long term:

Models are all over the place starting on Tuesday.  One common theme is retrogression of the upper-level high over us to the West.  If it just moves a bit west, we stay mainly dry from Tuesday onward but cooler, but not extremely cold (12z ECMWF, 00z Canadian, 00z GFS).  If it moves farther offshore, we could really get slammed with a late season arctic outbreak or snow.  For now, scenario #1 seems to be more likely according to the latest evening models (no, not because I don’t want to work a long and grueling snow/ice storm!).  But all is not lost even if that is the case through the middle of next week.  All the models still keep a chilly pattern around for awhile.

Feels Like March

February 7, 2006

* Note…if you folks can play nice, we’ll keep the comments unapproved and see what happens.  Up until tonight we’ve had to approve comments before they show up here. This should allow a freer flow of ideas, provided we all behave…Mark

Now back to weather…I’m really enjoying our nice weather and it looks as if it’ll continue all the way through the weekend.  There will be one significant change for Thursday-Friday.  A dying storm falls apart over us tomorrow, but behind it strong Canadian high pressure drops south.  This should give us our strongest Gorge/Easterly winds since before Christmas.  Temperatures will only cool slightly with the increasing February sunshine beating the cold air back.  Then another system tries to run into the ridge over us this weekend.  I doubt that will have much success either.

As for colder weather next week…very mixed messages.  All models still agree on some sort of retrogression of the key features over the U.S. (the western ridge moves out over the Pacific and the eastern trough moves back to the west).  But each model does things differently.  Maybe most disturbing (if you want a late season blast of cold air) is the new 00z Canadian and 00z GFS.  They both keep the ridge a little closer, which never allows real cold air into the Northwest U.S.   And the GFS more or less keeps us mainly dry next week too.  Makes me wonder if we will just end up with more ridging.

I should clarify that we CAN get cold air later in the season, but it’s EXTREMELY rare.  The poster below mentioned early March 1960.  That WAS an impressive cold snap, I had missed that one.  Wow! I see Troutdale for 3 days had highs of something like 28-34.  Salem stayed in the lower 30s with snow.

A Nice Break This Week

February 6, 2006

I started feeling a bit older this weekend for 2 reasons:

1.  Another spring is quickly approaching as I approach 40.

2.  I now own a minivan…which I thought wouldn’t happen until I turned 40 or so.

But, let’s move on, weather watching still makes me feel like a kid…looks like high pressure will hold strong over the Northwest through the early part of next week.  That means a period of sunny skies, warm days, and cool nights.  We often get cold & annoying easterly winds out of the Gorge in this pattern in wintertime (actually more than often, about 95% of the time!).  In this case though the wind won’t be too strong until Thursday & Friday.

Now, for you Arctic Air friends…models the last 2 days have increasingly been pointing towards a retrogression of upper-air features over the North Pacific and North America just beyond the 7 day period.  So how do you feel about "retrogression"?  Well basically it just means things sort of "back up" overhead.  The ridge right over the top of us moves well out into the East Pacific, and the cold trough over the middle of the country moves west towards us.  That would put us in some sort of northerly flow (each model is different in the details) after early next week.  This doesn’t necessarily mean we’ll have a late season cold blast or snow here in the valleys, but the weather pattern does seem to want to change to at least cooler around Valentine’s Day. 

Remember that we have seen significant snow as late as the 3rd week of February in the last 15 years.  BUT, we’ve never seen a high temperature NOT get above freezing after the 16th.  Basically we can’t stay frozen all day after mid-February.  Now, discuss amongst yourselves!…Mark

Saturday AM Update

February 4, 2006

Looks like the peak of the storm is on us right now (7am Saturday).  Winds are just beginning to drop at the Coastline.  Here in the valley we’ve had numerous gusts 40-50 mph.  The gusts are definitely coming with the showers, as stronger winds above mix down to near the surface.  I think we may see a gust or two to 50 mph in the metro area, but that should be about it.

One Last Storm Update

February 3, 2006

I just perused all the 00z model data (as of 8:30pm).  Everything is on track for a windy night and Saturday morning across the region.  BUT, it doesn’t look like a major windstorm, except at the Coast.
I think peak gusts may hit 90mph in a few spots at the coast, but at best only 50 mph in the western valleys.  Why?
1.  00z models are slightly looser with the pressure gradient from Eugene-Olympia
2.  Low has reached maximum intensity and will begin to weaken (fill) over the next 12 hours
3.  Satellite seems to show a landfall slightly farther north than 12z runs (more like N. Vancouver Island)
4.  00z ETA/NGM/MM5 show that landfall as well.

So this should be just a touch stronger than our little weather surprises on Christmas & New Year’s Day.

We’ll be starting coverage at 5am on GDO Saturday here at FOX-12, including Stephanie and Me.  See you then!