Light at the End of the Cold Weather Tunnel?

March 23, 2011

There are hints of a pattern change starting the middle of next week.  I see the GFS, ECMWF, and GEM ensembles from the 12z runs all show higher heights and a disappearance of the cold East Pacific upper level trough.  This would at least bring temperatures up to average.  The GFS would give us temps near 70 next Wednesday and into the 70s next Thursday!  We’ll see what happens, but even in the coldest springs we DO get periods of warmer weather inbetween the consistently chilly weather.  Remember in 2008 we had a historic mid-May heatwave…surrounded on both sides by unusually cool weather.  Between now and then (the next 6 days) cool and wet weather will continue.

I’ll be off on vacation now through the end of next week.  The next post PROBABLY won’t be until April 4th, unless some exciting weather event appears on the horizon.

I had a change of heart at the last minute.  Some of you asked if I could allow discussion to continue here…so I’ll leave the comments on.  If your comment gets moderated (for whatever reason), it might be several days before it gets approved.  I’ll check in only occasionally. 

Chief Meteorologist Mark Nelsen

Cold Spring Record Ahead?

March 22, 2011

After looking up all the numbers, I can confirm that we are now in 2nd place for the latest “first 60 degree temperature”  here in Portland.  Only one other year (1955) did we go beyond March 22nd with no 60 degree temp.  That year it finally hit the magic “six zero” on March 27th.  SO, if we make it beyond this Sunday without hitting it, we’ll be breaking a record similar to last year’s “latest first 80 degree temperature” in June.  Of course it’s not really a “record”, but a cold milestone to be celebrated with a warm drink, hot tub visit, or large bonfire I think.

Hopefully this isn’t just the beginning of a long and cold La Nina spring…we just did that 3 years ago, and folks are still cranky about the wet end to last spring and the chilly summer.  But that IS how we get averages…warm years even out with chillier years.  And the odds are definitely stacked towards a cooler than average spring ahead.  Luckily we don’t tend to average wetter than normal.

Chief Meteorologist Mark Nelsen

Plenty of Water For Summer

March 21, 2011

The mountain snowpack has made a tremendous comeback the last 4 weeks.  You may remember that through January and the first half of February we saw warm rain or dry sunshine most of the time up in the Cascades.

How things have changed…

4 weeks of cold and wet storms (with occasional short breaks too of course) have brought all Oregon river basins up to or above average for this time of year.  The best is the southern half of the state with 120-130% of average “snow water equivalent” on the ground.  That means there is an above average “storage” of water up in the mountains.

Take a look at the graph above.  It’s from about the 3,000′ elevation just west of Santiam Pass.  The smooth-looking blue line is the 30 year average snow water equivalent at that site for each winter.  Note the snowpack (at that elevation) tends to peak in early March.  Higher areas like Timberline Lodge follow 3-4 weeks later (on average).  The green line is last winter…remember the really bad El Nino year?  That’s it right there in green.  Then the jaggy blue line is this past winter up until today.  We were doing just fine until about the 2nd week of January, then the warm rains and dry weather took a real toll on the snowpack.  By Valentine’s Day there was only a little over half the normal snowpack on the ground.  Now you see what happened in the last 4 weeks!  The total just keeps going up and up.

Looking at the maps for the next 7+ days, I see no dramatic change.  In fact it gets wetter Thursday through the upcoming weekend.  There is a hint that maybe we could see a brief break about 8 days away…just 8 days away!  Like those arctic blasts.

My garden/yard is showing signs of the late growing season start.  Lawn hasn’t even attempted to grow, buds on trees and bushes look more like late February, and even the daffodils haven’t started yet.

By the way, I’ll be taking a 10 day vacation starting Thursday and I’ll be “shutting down” the weather blog during that time.  So if there’s someone you REALLY have to communicate with, make sure you get their email address or Facebook name by Wednesday.  It’ll just be better to have the comments off when I’ll be away from the computer for awhile.

Chief Meteorologist Mark Nelsen

A Very Wet March

March 18, 2011

Even if the rain stopped falling right now, this would be considered an unusually wet March.  As of 10pm we are up to 4.93″ of rain so far, and we’ll probably go over the 5″ mark later tonight or tomorrow afternoon with a few more showers.  So that makes 5″ by the 19th…only 11 days to go to April!

Here are the last 5 times we exceeded 5″ in the month of March:  2003, 1997, 1989, 1983, 1974.

The forecasting becomes a real pain now the next 7 days.  It’s a classic pattern of upper-level systems diving down towards California, while sending disturbances north over us.  Models typically don’t handle the small waves of showers well.  As a result we changed our 7 Day Forecas wording to “MORE DRY THAN WET” instead of “MAINLY DRY”.  I still believe there won’t be a ton of rain during the next week, but if we get a deformation zone (maybe Monday?), that can give a cool and drippy day.  That’s as opposed to afternoon showers (tomorrow and probably Sunday).

Not much else to talk about for this weekend.  My favorite moment today was when I read that RADIATION FROM NUKE PLANT REACHES WEST COAST in some sort of online headline.  Then I read the details:  it was detectable in Sacramento, at about one-millionth the dose we regularly get from bricks, rocks, the sun, and other natural sources.  Why isn’t the media telling us about the danger in all those rocks and bricks!!!  I’m going to cloister myself inside my house over the weekend just in case the sun tries to shine on me or a rock can see me…

Chief Meteorologist Mark Nelsen

No Radiation Threat

March 17, 2011

I’ve had a few emails the last few days wondering why we aren’t talking about the “radiation threat”. 

Because there isn’t any such threat. The nice picture of today’s rainbow from Katherine Budiao should help too.

This is akin to asking why I’m not talking about the snow threat in April…because the risk of that happening is so small why talk about it and feed into anxiety?  I’m amazed that scientists and government experts (and the President) can tell us there is no threat and still the conspiracy rumors still circulate.  Of course I did watch almost every episode of X-Files, so I suppose I can understand it a bit.

Take the meltdown at Chernobyl in 1986.  Eventually the radiation was detectable around a good chunk of the northern hemisphere, but harmful radiation only was a problem a few hundred miles away.  Just so we’re all clear on this…Japan is something like 5,000 miles away! 

So let’s talk weather.  Finally a nice slowdown in the showers this afternoon and evening.  There is quite a storm sitting offshore right now, and we should get some light rain out of it tomorrow.  But the low pressure center associated with it will never come inland over us.  Over the next 5 days we’ll see a bit of a split jet with energy digging south (well offshore) and then down into California.  This means a big slowdown in the weather.  Often we get some leftover showers from the south in this pattern, thus the MAINLY DRY on our 7 Day Forecast.  I don’t see temperatures shooting through the roof, but it won’t be nearly as cool as the last couple of days.  And most important…much brighter skies Saturday through early next week.

Chief Meteorologist Mark Nelsen

Lightning Strike Last Night

March 16, 2011

The lightning strike last night DID hit the Home Depot in Beaverton.  Our lightning data showed a strike almost directly over that spot.  Read the post earlier from “DobMom”…

My son, who works at Beaverton Home Depot, just called me and reported he was told that an antenna on top of Home Depot was hit by that mighty lightning bolt last night. The boom was extremely loud at ground zero and allegedly some metal latches on a sky light melted and some of the metal dripped into the store! Glad Home Depot was able to play lightning rod with not much harm done.

I Hate Snow (In Late March)

March 16, 2011

It’s snowing again…in the central and northern Willamette Valley foothills and even lower!  The picture above is from south Salem around 9am this morning.  I just received another from Gates (about 900′) that shows plenty of snow on the ground (1″ or so).  Oops!  I forecast a snow level near 3,000′, but apparently about 2,000′ lower!  It’s the same story we’ve seen several times this winter with steady heavy precipitation pulling down the snow level lower than expected.  Looking at the radar, it appears several inches could fall above 500′ or so before the precipitation runs out.  

It’s a nice curl of a wave that’s moving inland.  Once it moves east by midday, we’re into the showers and sunbreaks routine through sunset.  So once again a chance for hail or thunder in the afternoon.  The instability is not as great as yesterday, and organized thunderstorms don’t appear as likely, in fact SPC didn’t even give us our own “SEE TEXT” on the convective outlook map.  But for the weather geeks there should be some action.

Chief Meteorologist Mark Nelsen