A Dry Cross-Section

February 17, 2010

Here’s the 00z Cross-section from the WRF-GFS up at the UW. Several things to notice: First, there is very little moisture from the surfact to 10,000′ or so through Saturday afternoon (at least). Solid sunshine on the way. Easterly flow increases the next 24 hours and then stays very stable through the weekend. We have a strong east wind on the way but nothing too wild. Gusts around 50-60 mph in the Gorge, so probably at least 80 mph at Crown Pt. Should be good up there the next 3 days. Since the east wind mostly disappears for the season after the first week of March, this maybe be the last or one of the last chances to get thrown to the pavement? The other item of note is the cooling airmass the next 3 days. Check out the 0 deg. Celsius line.  Look how low it drops by Saturday afternoon.  That’s another reason I’ve lowered the high temp forecast the next few days compared to today’s high near 60.  We may have trouble hitting 50 on Saturday and Sunday.  Not exactly a cold spell, but a more typical late February cool east wind.

Models are still mostly together showing a return to westerly flow and rain by next Tuesday at the latest.  The ECMWF is the driest, the GFS a bit faster with the rain arrival.  The point is to enjoy the next 3-5 days of dry weather and sunshine!

Chief Meteorologist Mark Nelsen


A Warm Screw Up

February 16, 2010

Well, I had a really bad forecast score last week due to missing EVERY single high temp forecast and one low.  I need to be within 3 degrees; last week’s annoying cool east wind plus some extra warm sunny days messed things up big time.  The first day of THIS week is no different; I went for 55 and we hit 59.  I’m fine with the actual forecast (showers to PM sunshine) was fine.  Obviously some real challenges ahead temperature-wise the next few days as well.  We’re getting into that time of year where we can see unusually warm temperatures, let’s say 60+ from east wind coming down off the Cascades.  In the Thanksgiving to Valentines period our record highs generally come from warm southerly wind.  During this transitional time it’s always tough to forecast high temps.  Tomorrow we start out much cooler than today and have plenty of fog to start with too.  Then drying easterly wind breezes across the metro area by afternoon.  So I figure we’ll end up quite close to today.

I think it’s a different story Thursday through Sunday though as a cool pool of air develops to our east.  It’s pretty obvious on the WRF-GFS model.  Due to that I lowered high temps Thursday and beyond due to strong easterly wind (20g35 mph at PDX seem likely each afternoon).  In that pattern this time of year I think it’ll be tough to get above the mid 50s.  I could be low…we’ll see.    More likely on Thursday it’ll be 52 at Troutdale and 59 at Oregon City and McMinnville.  Coolest temps near the Gorge, warmer farther away etc…

I’m glad we stayed with a dry forecast for the weekend, I see the 00z GFS and ECMWF are still showing a change to wetter flow around Tuesday of next week.  The GFS is much cooler than the ECMWF.  The ECMWF looks like a return to warm systems and flat ridging over the West Coast for the very last week of February.  Either one says we can definitely turn on the faucets and probably take snow tires off too.  Tomorrow might be the big day to call off the rest of winter…

Chief Meteorologist Mark Nelsen


Back to Dry

February 15, 2010

A fun weekend for the Nelsens full of cultural enlightenment at the Monster Truck Monster Jam.   My kids need to be exposed to their heritage don’t they?  Plus my 9 year old son has collected something like 25 of those little trucks, so he was super-excited to go.  Wow…$8.50 for a drink?  No wonder I don’t head to our local sports arena much!  My friend got the prize for “first mullet sighting” though.  That would be ANOTHER $8.50 gone out of my pocket…

Moving on to the weather; a very clearly defined weather pattern coming up the next 7 days…REX BLOCK.  The details are a bit tricky, but they probably lead to the same effect…very dry.

An upper-level ridge develops just to our west and north Wednesday, then gradually gets pinched off as we head into the weekend.  Cold air slides down to our east Friday-Monday as undercutting systems start moving into California once again.  As of now it appears that dry northeasterly flow at the surface and above limits cloud cover and definitely rain.  That’s why Steph and I took the rain out of the weekend forecast.  I did just adjust the 7 Day forecast temps down a bit due to increasingly cool surface wind from the northeast.  I doubt we have  chance of hitting 60 anywhere beyond Friday, and maybe not even Thursday or Friday themselves.  But no matter the temperature, it’s going to feel like spring Wednesday-Friday afternoons with no cloud cover and temps at least well into the 50s.

So last Thursday/Friday I had decided to “pull the plug on Winter” either today or Tuesday on the air.  In fact I think I came up with that glorious idea while in the shower or ironing some shirts.  The plan was to make a big deal of the fact that I think we’re done with our chance for a big freeze or significant snow (2″ or more at PDX, the snowy grass in the city in March doesn’t count).  BUT, I got cold feet after seeing different variations of moisture just to our south and cold air just to our northeast this weekend and early next week.  It would be a risky move until the 7-10 day forecast resolves those details a bit better don’t you think?

Enjoy the rain tonight…looks real dry over the next week!

Chief Meteorologist Mark Nelsen


Snow & Ice Cover

February 13, 2010

Inspired by all the talk yesterday about snow cover on the ground in 49 states (drought in Hawaii means the 13,000′ volcanoes have no snow), I decided to probe a bit farther:

So I see that this is the 4th January with above average snow cover here in the USA.  Arctic ice is still way below average of course too, that’s the 1st image.  Click on the images for a better view, unless you have bionic eyes.  And the “bitter cold January”?  Actually the USA was slightly above average temperature-wise in the month of January.

One other note: January was the warmest on record for land areas of the Southern Hemisphere.  It was the peak of their summer of course and it’s been one for the record books.  Rio has been sweltering the last few days with the hottest weather in 50 years…they will probably have to take off even more clothes than usual for Carnival this weekend.  Is that possible?

Anyway, I have some thoughts on all the stupidity I’ve been hearing on talk radio the last few days (related to all the snow back east and global warming/cooling).  I’ve heard some of the dumbest and mis-informed statements blabbered by hosts and listeners on both sides of the issue.  When I get a chance I’ll post some of those.

Chief Meteorologist Mark Nelsen


Windy & Wet

February 12, 2010

It was nice to see the wind actually show up as expected today (as opposed to Thursday!).  Peak gusts were in the 30-40 mph range late this morning and then again with showers during the afternoon.  Scappoose really got soaked by the rain…capturing over an inch of rainfall.

Another system is approaching “Cascadia” this afternoon.  Just trying to capture part of the glory of the Olympics for us and connect to Vancouver BC somehow in that statement!  That warm front moves overhead early tomorrow morning (when I plan to be asleep), then most or all of the rain lifts to our north.  It could be a very nice mid-late afternoon!  And warm too!

Very slow weather continues in general the next 7+ days.  I think someone mentioned earlier today that it seems like I’m not posting as much lately.  My posting is directly related to our weather.  If there isn’t much happening I tend to post less.  You’d be amazed at the page views…anywhere from 40,000 hits on a big weather day down to 1,000 a day with sunshine!

There is a significant change in the pattern beginning the middle of next week.  Strong upper-level ridge of high pressure amplifies overhead.  The ECMWF continues (including the brand new 00z) holds onto this ridge more or less through the 10 day period.  The GFS has it retrograding to the west and north, allowing colder air to slip in from the east and then eventually wetter westerly flow to cut in from the west.  We’ll see how it turns out, but nice sunny weather is on the way for at least a few days late next week.

Chief Meteorologist Mark Nelsen


Snow in all 50 states??

February 12, 2010

Alright, let me start by introducing myself. I’m Pat Rosborough and I am the Good Day Oregon weather producer here at Fox 12. These mornings can get REEEEEEEALY slow so I think I’ll be making some posts to add to the excitement here. A really active last 24 hours, finally some excitement with the wind we briefly had last night here and at the coast. Peak wind gusts at the coast hit 69 miles per hour in Cape Foulweather and Garibaldi.

Snow slammed the east coast this week, putting many cities into the record total snowfall category. This little tid bit came into the newsroom this morning: A Oklahoma forecaster at the NOAA National Severe Storms Lab is predicting that there will be snow in all 50 states at once this week. A forecasted snowstorm that is already dumping snow in parts of Texas is making its way east and covering the southeastern states, including parts of the Florida Panhandle which are under a Winter Storm Warning. Remember the hard freeze they had in the middle of December?? I bet all those folks who move down to Florida during the harsh northeast winter are a bit confused.

It is not actually known if the phenomena of snow in all 50 states at once has occurred or not, but nonetheless it is worth mentioning.


Windstorms & High Wind Warnings

February 11, 2010

Nice picture for today…warm and windy coming up later, might be hard to find a palm tree this large in Oregon though.  Probably no windstorm, but the best south wind we’ve seen in a few weeks coming up this evening.  Nice wave developing on the cold front offshore sweeps by this evening, turning our easterly gradient now to southerly (screwed up high temp forecast yesterday!).  This should happen in the 5-9pm period.  Very similar to the surge of wind we saw back in mid January.  In fact I think it happened twice.  Not much southerly pressure gradient up the Valley, but nice mixing with a very warm airmass overhead later today should push some southerly wind gusts to 40-45 mph in spots.  It won’t last long either.  It’ll be done by 10pm.  I see the NWS has put out a Wind Advisory for the Metro Area.  Remember that’s for wind gusts in the 40-58mph range, which is perfectly reasonable this evening. 

Of course there is a high wind warning on the Coast, this one seems very reasonable as well with some gusts to 70 mph possible.  So I’ve got a few thoughts on that subject…

I could swear a high wind warning gets issued for every front approaching the Coast from October to March.  Okay, too dramatic, maybe more than half though.  We’ve discussed this in the weather center many times here at FOX12 over the years!  I believe the criteria is too low out there.  Currently if one or several spots gust to 58 mph that verifies a high wind warning.  Do you know how easy it is to get a gust 55-60 mph on the Oregon Coast in the winter?  The newspeople always ask us “is this going to be a big storm? there’s a high wind warning for the Coast!”.  70% of the time we have to say no and sure enough we hear of no damage/power outages at the beaches later.  I’ve  suggested several times over the years that the high wind warning criteria should be raised to 65-70 mph out there.  I’ve been told that emergency managers out at the coastal counties prefer that it stays the way it is because it helps them plan for outages etc…

I believe warnings should either be issued based on damage (50-65 mph gusts don’t cause any/much damage on the Oregon Coast), or be standardized for all areas.  Years ago the NWS made a wise choice to raise the high wind warning criteria for the western Columbia River Gorge to 75 mph (in a spot where people live).  It’s rare for the wind to get much above that in the Gorge.  In fact it only happens once every couple years or so.  There have been none this winter, and sure enough, there has been no damaging east wind this winter either.  And it only happened once last winter (that January windstorm).  The same thing should be done at the Oregon Coast.  I suppose a better question might be; are the forecasts for the people that live there or a traveling through the area?  Big difference.  A semi-truck driver probably wants to know if the wind is gusting to 60 mph when he’s driving down highway 101 or I-84.  But a local resident doesn’t need a warning for that speed in either area.

Just my thoughts…now discuss and enjoy the wind this evening.

Chief Meteorologist Mark Nelsen