A slow night…

January 31, 2011

Not a whole lot going on weatherwise for a 3rd calendar week.  Hard to believe February is only 1 hour away.  As I mentioned at some point during the last two weeks; our “real” winter here in the lowlands of the Pacific Northwest is late November through about mid-February.  Hmmm…that only gives us 2 weeks or so to get some sort of big frozen storm.    Not time to call off “winter” yet, but I’m getting closer.

That’s (blast of winter) clearly not going to happen in the next 7 days.  A strong ridge of high pressure is going to remain over the West Coast through at least next Monday or Tuesday (the 7th or 8th).  Beyond that…who knows.  Most models either put us into some sort of colder westerly flow or something somewhat more exciting.  But even that is beyond 8 days out and each run is different.    So enjoy the crisp sunshine.  Hopefully that Vista House sensor will get rebooted in the morning; since tomorrow should see the strongest easterly Gorge gradient of this episode. 

The airmass over us has cooled dramatically in the last 24 hours.  Check out the KPTV Tower sensor…42 at this time last night and now around 30 up there at 1,800′.  We might not get much above 40 degrees in a good chunk of the Metro area tomorrow.  Spots near the Gorge will hover in the 30s all or most of the day tomorrow.  Combine that with the wind and it’ll be our coldest weather in a month.

Chief Meteorologist Mark Nelsen

Lots of Cold Sunshine Ahead

January 30, 2011

This week should be mostly sunny, but much cooler then last week since we’ll see cold east wind picking up overnight and into tomorrow.  Other than the strong east wind and chilly temps, no other significant weather on the way the next 7 days, so the rest of this brief posting is for the weather geeks.

I didn’t have internet, phone, or Netflix Instant Viewing until about 9pm tonight; that’s what happens for 6 hours when you live out in the country.  We actually had to communicate around home…wow! (a joke…mostly).  So after seeing a few emails about dramatic model differences I wanted to chime in; once I could actually look at data/maps.  The only model run that is obscenely colder than others the next 48 hours is the MM5-NAM from the UW.  All models show a nice surface high developing now (already 3+ millibars through Gorge and gusts to around 40 mph at Crown Pt).  That strengthens and should be maxed out on Tuesday.  Definitely a good day to visit Vista House!

So the MM5-NAM model shows highs between 10-15 degrees at The Dalles Tuesday, while others show 25-30 or even a bit higher.  I have no idea why, but with upper level heights bottoming out around 560 dm. at 500 millibars, I can assure you we won’t see highs in the teens in the lower Columbia Basin!  In the past I’ve generally ignored the MM5-NAM on surface temps, often noticing that it’s “weird”.  That’s the best way I can describe it.  It’s done well on surface low placement earlier in the winter, but those temps are often strange.  I thought it might have the snow cover initialization showing snow over us, but that’s not the case, I checked.  Highs around 30-35 degrees at DLS the next few days usually mean 40-45 at PDX, which is what our 7 Day forecast shows.  Our WRF-RPM shows highs right around 40 both tomorrow and Tuesday at PDX.

One more thing…occasionally my service provider for my weather page somehow replaces the uploaded page with a blank image for several hours.  Then it takes care of itself.  Just add a “2” before the “.html” and that’s a static file that’s always there even when this happens.  Drives me nuts too, but the 2nd page helps ease the pain quite a bit.

Chief Meteorologist Mark Nelsen

Cold Air Arriving Soon

January 30, 2011

Our coldest and windiest weather in a month is about to move in for the next few days.  Forget about any rain, it looks like modified arctic air is now spilling into Western and Eastern Washington from the north.  It’s most noticeable with the dewpoint and wind both in NW Washington and then surging down through the Columbia Basin of Eastern Washington.  East wind should start blowing through the Gorge this afternoon and will rage for at least 3-4 days.  It might even be as strong as it was during the ice storm event about 3 weeks ago.

Especially for those of you on the east side of the Metro area; get ready for some very cold and windy weather.  The bonus is that most of this week will be sunny and bright!

Chief Meteorologist Mark Nelsen

April in January; A Very Warm Day For Some

January 27, 2011

Today was a fabulous late January day across the region; definitely a case of Spring Fever for those of you able to experience it.  Many areas saw temps up in the March or early April range. 

At the beaches, temps 60-70 degrees.  Newport and Tillamook hit 66, Lincoln City 65.  In the Willamette Valley:  the inversion broke late this afternoon except in the north part.  Salem jumped to 57, Eugene 62, and two different RAWS sites between 500-1000′ on the east side of the Valley hit 66.  In the Cascades and Cascade Foothills:  67 degrees at Horse Creek (3400′), 66 at 1,100′ near Estacada, 60 at Brightwood, 61 at Corbett, and 62 near the Larch Correction Facility in Clark County (1,200′).  A real scorcher above 500-1000′ in general by January standards.

Much cooler tomorrow with a cold front and “onshore” flow developing soon after sunrise.  Mesoscale models show a real nice surge of solid cloud cover and some showers as the day goes on.  So tomorrow and Saturday will be quite gloomy and drippy, but no significant rainfall.

Looking ahead…I think we actually have some mildly interesting changes coming up; we’re talking baby steps here folks.

1. Models have changed a bit the last 24 hours for Sunday through the middle of next week.  An arctic high plunging down through the middle of the country comes a bit closer to us, shoving colder and drier air south east of the Cascades later Sunday and Monday.  Then a strong upper-level ridge moves directly overhead, capping the cool and dry air in the lowlands the rest of the week.  This change means that instead of more fog/sun and mild temps, we’ll likely see cool, sunny (little/no fog), and windy conditions starting Monday.  I actually like the crisp and cool weather better than rain.  But it’ll be strange to have a 2nd week with little/no rainfall.

2.  Some models have had some slight retrogression to the persistent Western Ridge & Eastern Trough pattern.  Some push the ridge a bit farther west, allowing cooler air in from the north, but other runs say no…more of the same.  The 12z & 18z GFS still have little or no rainfall through the 16 day period.  If that’s the case, then winter here in the lowlands is toast.  But all it’ll take is a little retrogression-action and we’ll be back in the “winter business”.

Chief Meteorologist Mark Nelsen

Where’s La Nina?

January 25, 2011

The whining is beginning to pick up.  From two areas:  First, the general public is now beginning to notice that this January is one mild month!   Snowpack is well below average in the Cascades in the last week of January during a moderate-strong La Nina winter.  I don’t think anyone expected that!  And the average weather junkie noticed the issue about two weeks ago when any chance for low elevation snow or cold totally evaporated from forecast maps.  Two weeks later…still nothing is in the forecast through at least the first few days of February (middle of next week). 

So what’s going on?  The big picture is that we’ve seen persistent upper level ridging near or over the west coast of North America most of this month, and that won’t change in at least the next 7 days.  A deep and cold trough is situated over SE Canada, bringing wave after wave of cold and snow to the eastern 1/3 of the USA at the same time.  Most of the population of the USA is east of the Mississippi River, so we hear a lot more about that.  Not much attention has been given to our mild weather, or the extremely mild weather in most of northern/eastern Canada.  Check out the surface temperature departure from normal over the last 14 days…well above average in the western USA.

I should point out that I was NOT one of those forecasting a “mother of all winters”.  In fact that’s the 2nd or 3rd time in the last 5-6 years I’ve heard certain people forecast that as early as August-September.  Talk about wishcasting…  But I was definitely one of those that believed we had a better than average chance for snow/cold/action this winter.  And there is still time for that.  The last 3 weeks of February COULD still be crazy; we don’t know that yet of course.  But it COULD happen.  Winter is definitely not cancelled yet.  Now if nothing has changed two weeks from now, then that statement would be perfectly reasonable.  We don’t get prolonged arctic blasts or days-long snowstorms with highs below freezing after about Valentines Day.  The increasing sun angle starts to take it’s toll on marginal snow/ice climates like ours by that time.  So I would argue that REAL winter in the lowlands of western Oregon and Washington is over after about mid-February.  That’s only 3 weeks away.

The more important question is why have we have such a strong ridge over us for so long in the middle of winter and why the atmosphere seems to be so locked up?  I haven’t heard a good reason yet.  Cliff Mass talks about it on his excellent blog today here.  And I read an interesting article in the New York Times today that had a few theories.  Maybe the most important point to take from that article was that climate scientists and meteorologists can only guess for now.

So how can this possibly happen during a moderate-strong La Nina?  It’s very rare, but it has happened before.  1999-2000 was a very tame winter, 2nd year of a 2 year long La Nina.  Snowfall that winter was below average in the mountains, although the heaviest snow WAS in January.  Otherwise I don’t see any other January as pitiful as this one during a moderate-strong La Nina winter.  A bit unprecedented.

For the skiers and snowboarders, the good news is that snowfall in the mountains during La Nina winters tends to be best in February and March, so there’s still plenty of time for things to turn around.

Chief Meteorologist Mark Nelsen

The First Live Local Wedding Center

January 24, 2011

I never thought the FOX12 Weather Center would turn into such a hot spot, a romantic getaway, a place where co-workers come in and scream about rings.   But apparently women (and men) are attracted to us weather types.  Within the last 6 months I’ve been told “I’m getting married” by 3 of my 5 co-workers.  Andy and I are still married (to our wives) and that’s not changing.  But yes, lots of disappointment by singles all over the metro area as you hear that Sophie, Brian, and Stephanie are all getting married within the next 6-8 months.  In fact two are getting hitched up the same day!  Not sure how that happened or what’s in the water around here.  I’m no matchmaker named Yenta for sure.  I can’t say enough good words about the three of them too.  They are wonderful coworkers and great people; they’ll do just fine in the future.  Congratulations!

Now, as for weather…there’s hardly anything to talk about.  A nice inversion the next few days.  Enough east wind to clear out the fog for most of the Metro area Wednesday-Friday, but otherwise it appears the mild and mainly dry January weather is going to continue into early February.  Maps are real boring through at least the next 7 days…

Chief Meteorologist Mark Nelsen

Mild January Continues…

January 21, 2011

Another two days and I see very little to talk about on the maps.  Incredibly dull weather is likely the next 7-10 days in the Pacific Northwest.  A large blocking ridge sits near the West Coast through the period with little to no precipitation.  Yes, this pattern is very similar to what we see in El Nino winters, not La Nina.  This is going to end up being one strange winter!

There is only1 thing I see that could be interesting next week.  Maybe lots of east wind if the upper ridge has the right orientation.   A very strong inversion forms by midweek.   Check out 850mb temps in the +10 to +15 deg range.  That’s highs around 60-65 in the Cascade foothills.  I can guarantee you won’t see 60 with an east wind in January here in the Valleys…more likely 45-55 in the cool low-level air.  That squeezes the easterly flow through the Gorge down very low.  By the way, the Crown Pt. sensor has a fresh battery, and is somewhat working again today.  But obviously the signal is still having trouble with the concrete.  It looks fine after getting beat up with 80-100mph wind though.  Rumor says there might be a brand new, more permanent sensor with a solid signal before winter is out…we’ll see.  That would be nice…I’ll keep you updated.

Chief Meteorologist Mark Nelsen