Pacific Northwest Weather

[invisible]

I found something is interesting about La nina winters with snowfall totals.

Sea/Tac Airport

1950-63.60
1954-23.30
1964-18.20
1970-16.10
1973-4.20
1975-4.90
1988-14.20
1995-11.00

For normal year is 11.70 inches.

Bellingham Airport

1950-39.20
1954-15.10
1964-36.70
1970-44.90
1973-13.40
1975-11.30
1988-11.50
1995-12.30

For normal year is 13.70

Some years had incredible snowfall totals.

[AnthonyC]

Dude, STRESSFUL WEEK!! Between AP tests and final decisions regarding Gonzaga University, I've had it will school. Sorry I have not posted much lately.

There's not much to say...tomorrow is the most active day of the week. Looking at latest satellite pics, the cold front off the coast is becoming negatively tilted and the surface low is racing north. Very indicative of the entire winter season...another upper level low is beginning to cutoff down in California. Plain and simple...we'll see a batch of steady rain as the warm front passes by...followed with numerous showers and an active PSCZ.

After that, partly sunny conditions return...but will no firm ridge of high pressure, temperatures won't be too impressive and it won't be perfectly sunny. The weekend is a toss up...Saturday looks like the best day.

Anthony

[TT-SEA]

For those hoping for a La Nina... the chances are not that great.

The weekly update from Australia (5/3/05)...

Some of these models including the Australian POAMA model suggest further development toward an El Nino event, while others suggest neutral conditions for the southern winter / spring. None of the models are predicting a La Nina event.


The very important SOI is falling again after rising recently. It is now down to -11.2 and falling.

Negative SOI = El Nino
Postive SOI = La Nina

Now... El Nino usually means warmer and drier than normal here. There are exceptions in well established negative PDO situations. Which we are not in... and cannot be this year.

[Perturbance]

The Bend Bulletin has an article on some comments the Oregon state climatologist made on Monday. He believes that we're in a 20 year La Niña cycle that began in 1995.

"I think we are in a long-term wet cycle and we're in a dry cycle within that wet cycle," George Taylor said after a lecture Monday night at Central Oregon Community College. "I think over the next 15 years we're going to go back to being really wet again."

*shrug* Back during our warm and dry spells in February and March he kept saying that dry winters following wet falls meant wet springs 2/3rds of the time. While that looks true so far, I don't remember fall 2004 being particularly wet, at least in Corvallis.

[TT-SEA]

Also interesting... 4 of the 5 analog years today (5-day mean) are from the warm cycle 1975-present.

So the current pattern is not so overwhelmingly similar to a cold phase pattern.

[andycottle]

Good evening all! Pretty much a nice day here...that is after the clouds started to breaking up early this afternoon. Temp just a little warmer than yesterday. My high for today was 65 with a low of 50.

Acording the AFD tonight....we could see an active PSCZ tomorrow afternoon. I`m off from work at 2:30pm tomorrow...so hopefully I`ll be home in time to catch the action if it developes. Here`s part of the AFD. --Andy

AFTERNOON CONVECTION IS A POSSIBILITY. 00Z NAM BUFFER SOUNDINGS SHOW LI`S DOWN TO -1 OVER PUGET SOUND WEDNESDAY AFTERNOON. AFTERNOON TEMPERATURES ARE RIGHT AT THE CONVECTIVE TEMPERATURES. THE EQUILIBRIUM LEVEL IS ABOVE THE -20 ISOTHERM SO THUNDER IS POSSIBLE. THIS DEPENDS GREATLY ON HOW QUICKLY THE WARM FRONT LIFTS NORTH AND HOW LONG IT TAKES FOR THE CLOUD COVER TO DEVELOP BREAKS IN THE AFTERNOON.

[andycottle]

Looking at tonights Sounding data and MM5 model...lifted indices for tomorrow afternoon are around -1, -2 with CAPE values of near 400 J/KG...so T-Storms look pretty good. And PW values are well over half an inch and TT index in the upper 40`s to near 50. So if get some good sunbreaks just after the passage of the warm front...should get some decent down pours and good rumbles of thunder.

-- Andy

[andycottle]

Good morning all. A cloudy morning here with scattered light showers in my area. So far precip has been non measureable. Current temp is 53 with humidity 100%, DP 54, and baro steady at 29.68. Looks like I could some active t-storms later on this afternoon. Bring on the storms!

-- Andy

[donsutherland1]

Perturbance,

You mention that an Oregon climatologist suggested that a "20-year La Niña cycle" began in 1995. That's another way of stating that a new PDO- cycle had begun.

While it is possible, a cluster of La Niña years, is not sufficiently strong to make that case. In fact, 38 of the last 39 months have seen warm anomalies in ENSO Region 3.4. Nothing comparable happened in the last PDO- cycle.

In my view, we're more likely in a transition to a new PDO- cycle but not yet there. Of course, there is research that suggests that there are two embedded PDO cyles--a shorter-term one and a longer-term one.

[TT-SEA]

Don...

Any thoughts on the dabte over cause and effect.

In other words... does the PDO change eventually affect weather patterns or the other way around?

It looks like the weather patterns respond to a change in PDO. But there seems to be a lag of 2 or 3 years.

So when we do finally shift to the cold phase of the PDO... we may not see an immediate effect.

[andycottle]

Hey Guys....I`m home! Actually just got home about half hour ago. Anyway...check latest seattle radar. Nice storm cell over Tacoma right now....and if holds togeather, it just may be heading my way. This storm cell could contain some hail, specifically near 0.50"...per WeatherTap storm track table. -- Andy

[weather girl]

Although right now I think we'll have a hard time reaching La Nina thresholds through this coming summer, I think our good friend down under (the Australian ENSO forecaster) has, perhaps, overestimated a developing El Nino. I say that with all due respect. Eastern Pacific temperatures are already weakening. However, I am starting to resign myself to a warmer than normal PNW summer as El Ninos tend to have "memories". Ugh. Will take ENSO neutral at this point. Just in case you didn't see it, this is from the CPC regarding the Kelvin wave which you can clearly see in images has hit the SA coast:

A NEW BUT SMALL AREA OF GREATER THAN 1 DEGREE C ABOVE NORMAL
SST HAS DEVELOPED IN THE EASTERN EQUATORIAL PACIFIC BETWEEN 95W AND 120W...
PROBABLY AS A RESULT OF THE EASTWARD MOVEMENT OF A STRONG KELVIN WAVE ALONG
THE THERMOCLINE ABOUT 50 TO 100 M BENEATH THE SURFACE IN THAT AREA. LATEST
OBSERVATIONS SHOW THAT THE ABOVE NORMAL SUBSURFACE TEMPERATURES ARE WEAKENING
AS THE KELVIN WAVE BEGINS TO SHOAL OVER THE EASTERN PACIFIC.

[andrewr]

Currently I'm getting a thundershower. VERY HEAVY RAIN and lots of thunder, but no lightning sightings yet.

[TT-SEA]

I am not sure about the El Nino / La Nina situation.

I think a weak El Nino is more likely than a La Nina this coming winter. Without a well-established cold phase PDO regime... this will likely mean another warmer than normal winter.

It just feels like global warming has tipped the scales. Just an instinct I have.

And its beginning to feel like May is going to be another above normal month... after today we will be 5+ degrees above normal already for the month. We just cannot get below normal temperatures lately. Even with rain we end up above normal. Maybe by the middle of the month we might see some temperatures below normal. But until then... expect above normal temperatures to continue for the most part.

[andycottle]

Hi guys.

So much for the T-storms in my area today that I thought were going to happen, because I thought for sure there would be some. Acording to Seattle radar....it appears that most shower/thunder shower activity was down in the south Puget region late this afternoon. And right now as of 6:23pm, radar is showing moderate showers with a few possible rumbles of thunder from about Olympia down to roughly the Centralia area. Thoes showers appear to be heading on a some what slow North bound track. Eles where around the sound....skies have ranged from cloudy to partly cloudy with a few sprinkles here/there. I for one experienced a few light sprinkles late this afternoon. So it seems that the airmass may been a bit more unstable down there than up here in the central sound region. Hopefully we`ll have better luck with t-storms in my area the next time an unstable airmass moves in over the Puget Sound region.

-- Andy

[donsutherland1]

TT-SEA,

I support the research that indicates that the PDO mainly shapes patterns. The idea that there are shorter- and longer-term PDO cycles that co-exist (JPL), suggests that it is less likely that the patterns drive PDO cycles.

[TT-SEA]

Don... I completely agree.

That means even if the PDO went sharply into the cold phase this year... which is not happening yet... it would probably be another 2 or 3 years before we saw any real effects.

Then you factor in global warming... and the cold phase of the PDO (when it does come) should be much less dramatic.

-A neutral or weak El Nino situation this winter.
-PDO likely to be positive
-Above normal temperatures in place so far this year

In my humble opinion... its looking more and more like a warmer than normal winter for the PNW!!

[TT-SEA]

Also... 9 of the 10 analog years today are from PDO warm phase years mostly between 1980-1997.

[AnthonyC]

Going on pure instinct, I say we'll have a neutral winter of 2006. This means a variety of weather...some heavy rain periods, an arctic blast or two and maybe a good windstorm. I do not think we'll have another warm winter.

As for today, not a bad day...we had very little rainfall this morning. The system became negatively tilted and moved into California. Tomorrow may actually be a nicer day...with warmer temperatures. There's a weak shortwave in the northern branch, but alot of the energy is headed into British Columbia.

So basically, we're stuck in this pattern that is not warm/sunny but not cool/wet. Pretty monotonous if you ask me. I'm praying we return to a warmer/drier pattern in the near future.

And another instinct prediction...I think summer of 2005 will be warmer and drier than normal. We've been in this pattern for the past three summers...I think it will continue for one more summer.

Anthony

PS-Where is everyone on this site? What happened to snow_wizzard, r-dub, etc? The only people posting are tt-sea and andycottle.

[andycottle]

Hi Anthony!

Not sure where Randy has been, but would guess he has been busy lately. As for snow wizzard...probably the same. Being busy in his knowledge of climate . -- Andy