February 2008

Overview

February started cool and wet, but the second half of the month was unusually (and unexpectedly) dry. Temperatures remained on the low side, however.

This year’s snowpack remains one of the deepest ever, despite dropping a bit (compared to average) during the month.

Table 1 is a summary of monthly averages and totals at selected stations throughout the state. Table 2 lists daily temperatures and precipitation for most of the locations listed in Table 1. In Table 3, monthly precipitation totals throughout the state are listed. Figure 1 is a map showing the percentage of normal precipitation statewide for the Water Year.

Basin Summary

Here is a summary of water indicators at the end of the month, by river basin:

* Last month’s numbers; current data unavailable at press time

n.a. Not available
(1) Percent of normal November precipitation, from NOAA Cooperative sites
(2) Percent of normal seasonal precipitation (since Oct. 1), from NOAA Cooperative sites
(3) Percent of normal seasonal precipitation, from Natural Resources Conservation Service (NRCS) SNOTEL sites
(4) Percent of normal snow water equivalent, from NRCS SNOTEL sites
(5) Percent of normal November stream flow, from U.S. Geological Survey (USGS)
(6) Percent of normal seasonal stream flow (since Oct. 1), from USGS
(7) Surface Water Supply Index, from NRCS (-4 = very dry, 0 = normal, +4 = very wet)

Forecasts

The Climate Prediction Center’s (CPC) forecasts for March-May appear below. Temperature probabilities show equal chances of above-, near-, and below-normal for Oregon (except for cooler temperatures along the coast), and precipitation probabilities also show equal chances.

Oregon Climate Service predicts below-normal temperatures and above-normal precipitation for the next three months.

ENSO Update

Australian Bureau of Meteorology, March 5, 2008

The La Niña event in the Pacific basin is mature, and continues to influence the climate of eastern Australia.

While the far eastern Pacific Ocean has warmed, cooler than average sea surface temperatures (SSTs) continue to extend across the western to central equatorial Pacific. When combined with enhanced Trade Winds, suppressed cloudiness in the central Pacific and a strongly positive (+21) Southern Oscillation Index (SOI), it is clear that the atmosphere and ocean are firmly reinforcing each other, sustaining the La Niña event. The SOI reached a record value for February of +21.3, the highest for any month since +22.4 in November 2000.

Warmer than average water in the western Pacific sub-surface, has shown only the slightest signs of eastward propagation. Central Pacific SSTs have not been impacted yet; in fact they've continued to cool. However, a gradual weakening of the cool anomalies in the central Pacific would be consistent with the latest outlooks from computer models. These show Pacific temperatures gradually warming over the next few seasons, although remaining below La Niña thresholds until at least the end of the southern autumn.

CPC ENSO Forecast (March 6, 2008)

Atmospheric and oceanic conditions during February 2008 continued to reflect a strong La Niña. Equatorial SSTs were more than 2.0°C below average across large portions of the central and east-central equatorial Pacific, and the corresponding weekly values of the Niño-4 and Niño-3.4 indices remained between _1.6°C and _2.1°C during the month. In contrast, SSTs in the far eastern equatorial Pacific were above average during February 2008, in association with a warming trend that began in mid-December. The upper-ocean heat content (average temperatures in the upper 300m of the oceans between 180° - 100°W) remained below average across the equatorial Pacific during February, with the largest temperature anomalies averaging _2°C to _6°C at thermocline depth. Consistent with these oceanic conditions, stronger-than-average low-level easterly winds and upper-level westerly winds persisted across the central equatorial Pacific, convection remained suppressed throughout the central equatorial Pacific, and enhanced convection covered the far western Pacific. Collectively, these oceanic and atmospheric conditions are similar to those accompanying the last strong La Niña episode in 1998-2000.

Retirement!

George H. Taylor

By now you’ve probably heard the news. After nearly 19 years at OSU, I’m retiring.

Unfortunately, some things being said (and written) about me are either inaccurate or misleading, so I’m going to take this opportunity to set the record straight.

“ Taylor calls himself the state climatologist”

Yes, and I call myself George, because that’s what my parents named me. And in 1991, Steve Esbensen, chair of the Atmospheric Sciences Department at OSU, appointed me as State Climatologist (SC).

Originally, the SC position was a Federal one, but those were eliminated in 1973. States were urged to appoint their own SC, and Oregon did so in 1978. As in the case of most SC programs, Oregon’s position was a faculty appointment at the land grant university. Very few were appointed by Governors. Larry Gates, Allan Murphy and Kelly Redmond preceded me as SC at OSU. I arrived here in 1989, when Kelly left. In 1991, when the SC received state funding for the first time, Steve appointed me.

By the way, George Keller of OSU and legislators Cliff Trow and Tony Van Vliet were instrumental in getting funding for the office. Senator Trow sponsored the funding bill.

“ Taylor doesn’t believe in global warming.”

Sure I do, and global cooling as well. Climate varies all the time, on a variety of time scales.

I believe that climate changes as a result of a combination of natural variations and human effects (including, but not limited to, greenhouse gases). But in my opinion, past changes in climate (in Oregon and elsewhere) are more consistent with natural variations than with increases in greenhouse gases.

That doesn’t mean things won’t change in the future. That doesn’t mean we “shouldn’t do anything.” But based on looking at climate data for many years, I am convinced that the effects of things like tropical Pacific ocean conditions and solar radiation has dominated our climate, at least in the Northwest.

“ Taylor was probably asked to resign.”

Nope. I’m leaving on my own, and the decision was mine (in consultation with my wife, Cindy, of course). Here’s why:

1. In 2003, I was diagnosed with cancer. Surgery, chemotherapy and radiation followed. Also baldness (temporarily). Things look great now. But cancer really got my attention!

2. Last summer I turned 60. That got my attention as well.

I started wondering “shall I keep doing what I’m doing, or do something else for the rest of my career?” I decided on the latter.

I’m going to start a small consulting business. Initially, at least, I’ll focus primarily on a type of storm analysis called “Probable Maximum Precipitation” (PMP).PMP is required whenever a dam or large water containment structure is built or relicensed. PMP helps determine the maximum flood that might be expected, and this in turn determines how big and strong the dam needs to be. A very important application of weather and climate, for sure, and not many scientists are qualified to assess PMP. That will probably keep me busy.

And I’m hoping for other new and interesting pursuits. I may be retiring from OSU, but not from weather and climate studies.

It’s been a fun ride, but I’m not going to stop riding. I’m just going to get on a different horse.

A Weird Year

It’s been a weird year. In the Northwest, we’ve had the snowiest winter in many years. Even with a relatively dry second half of February, the snowpack in the Willamette drainage is at 172 percent of normal.

Baghdad has had snow on several occasions. I read somewhere that snow had not been reported there since 1916. My son-in-law, Matt Halverson, is stationed in Baghdad with the US Marines, and confirmed that they had, indeed, received snow.

China has had severe blizzards; according to some reports, they flattened about 10 percent of its forests.
Subtropical northern Vietnam experienced a prolonged cold spell in January that sent temperatures as low as 28 degrees F – unusually cold for that location. Australia and Argentina have had a very cold 12 months, causing a very poor wheat crop – a major reason why wheat prices now exceed $12 per bushel, more than three times higher than a year ago.

In the continental United States, things were rather sedate, despite the tornadoes that struck the Southeast in January and the heavy snow. This winter ranked as the 54th coolest on record at 0.2 degrees F. above normal, according to preliminary figures released Thursday by the National Climate Data Center in Asheville, N.C. That put it about in the middle of the winters since 1895. But the winter was wet: it ranked as the 18th wettest winter, dropping an average of 2.7 inches of moisture on the country – just over half an inch above normal.

Do any of these statistics have anything to do with global warming? Or with climate change? In a word, no. A single year doesn’t mean much when it comes to climate.

Recently I gave a presentation at a local high school on climate, and an OSU colleague presented as well. He suggested that hurricane Katrina and the European heat waves of 2003 were “proof” that global warming was occurring. But I don’t think that’s true at all. Single weather events, single seasons, even single years mean very little – anything can happen in such short time periods. Rather, it is necessary to look at longer-term trends before making such declarations.

On a weekly basis, natural variations in weather "are far greater than any climate-change signal," says Michael Halpert, deputy director of the National Weather Service's Climate Prediction Center. Winter temperatures in North Dakota can drop as low as 30 below zero F or rise to 50F above. Against such strong temperature changes, "folks living in North Dakota aren't going to see that it's a degree warmer or a degree colder" based on long-term trends in global average temperatures, he adds.

But average temperatures in North Dakota have been cold, just as they have been in Oregon. The reason: La Niña conditions in the Pacific, and a very quiet Sun. La Niña, characterized by cooler-than-average water in the tropical Pacific off the west coast of South America, generally gives us our wettest, coolest, and snowiest winters. Ditto for the rest of the northern tier of states. The cold winter in the northern US is just what one expects from La Niña.