A cooler 'La Nina' may mean more snow than usual this winter

Our snowfall predictions were originally planned for Oct. 18. I'm still compiling our detailed winter city forecasts and promise to have the complete list next week and more information on the upcoming winter season. However, as a preview, I'm expecting Coeur d'Alene and surrounding regions to have approximately 10 percent above average snowfall for the winter of 2010-11. At my station on Player Drive, I'm currently anticipating between 75 and 80 inches of the white stuff.

Next week in ‘Gems,’ I’ll be issuing my annual city-by-city North Idaho snowfall predictions for the fast-approaching winter of 2010-11.

I base my outlooks on various weather factors, including sea-surface temperatures and the latest data on solar storms (sunspots). Here are these reports from Meteorologist Randy Mann:

A MODERATE LA NINA IN THE SOUTH-CENTRAL PACIFIC WATERS

Sea-surface temperatures near the West Coast of South America and along the Equator are still much cooler than normal. We’re still declaring a moderate "La Nina" sea-surface temperature pattern. It’s possible that we could see a strong La Nina if cooling continues in this region.

Last week, there was some slight warming of sea-surface temperatures along the Equatorial regions. Two isolated regions formed where readings went "above normal." They were relatively small, but commanded close attention.

Over the last seven days, however, La Nina has strengthened slightly. The two small pools of warmer waters have since decreased. It appears that this moderate La Nina will be with us through at least early 2011, probably longer.

During the warmer El Nino events, the Sub-Tropical Jet Stream becomes stronger and moisture flows along that path into California, the Desert Southwest, Texas and the Deep South in a pencil-like "straightline" course.

During the cooler La Nina event, the Maritime Polar Jet Stream often becomes stronger and the Sub-Tropical Jet Stream is much weaker. The northern portions of the U.S. usually receive higher snowfall totals and colder temperatures. We’re already seeing this pattern with increasing moisture in the northwestern and northeastern portions of the country.

During the La Nina winters of 2007-08 and 2008-09, all-time record snows were reported across much of the northern U.S. and southern Canada. The Maritime Polar Jet Stream became more "loopy" with this pattern, like a piece of spaghetti.

Ocean temperatures near Ecuador and Peru are still about 3-6 degrees below normal levels. Readings along the Equator are even colder in some isolated areas.

The Southern Hemisphere is now into its spring season, so it’s possible that we may see further cooling of the Equatorial waters between now and at least the end of October, probably longer. Before 2010 expires, we may start to see warming sea-surface temperatures, especially as the Southern Hemisphere goes into its summer season.

We should likely see additional tropical storm and hurricane formations into at least mid October. Ocean waters are much warmer than normal in the Atlantic and Caribbean waters which would enhance tropical storm and hurricane development.

For the upcoming winter season, if La Nina continues to maintain its strength, or even intensify, conditions north of I-80 may be much colder and snowier than normal as the Polar Jet Stream intensifies.

SOLAR STORMS ARE GOING "BACK AND FORTH"

During a cycle when the sun was supposed to see a dramatic increase in sunspots, it again "went quiet," on Sept. 9. Since that time, however, there have been an average of 20 to 40 sunspots observed daily on the sun's surface. There was a high of 57 sunspots on Sept. 26.

During the "peak" of solar activity in late 1990s, we were seeing 200-300 solar storms each day. The next solar "maxima" cycle is due in late 2012 or early 2013. So far, there isn’t a strong indication of a dramatic rise in solar activity, but that could change quickly. Many scientists suggest that the upcoming maxima will be very strong, but there hasn't been much evidence yet to support this possible event.

With solar activity slightly higher than the heavy snowfall years of 2007 to 2009, the northern regions will not likely see record amounts of the white stuff this upcoming winter season. However, we wouldn’t be surprised to see snowfall totals above normal levels, especially with the moderate La Nina in the south-central Pacific Ocean. Stay tuned.

NORTH IDAHO WEATHER REVIEW AND LONG-RANGE OUTLOOKS

Our tomatoes are continuing to ripen in our thus far frostless gardens thanks to recent afternoon highs in the pleasant 70s. On Oct. 2, the mercury hit a near-record maximum for the date of 83 degrees, probably the warmest day until at least next April in Coeur d’Alene.

As of this Thursday morning, Oct. 7 writing, we still haven’t seen even a single morning in the 30s yet this month. Our tomatoes and other sensitive plants remain uncovered overnight, quite unusual indeed for so late in the season.

But, our luck frostwise may run out this second week of October, as much cooler air from the Gulf of Alaska invades the Inland Northwest. By Tuesday morning, Oct. 12, Columbus Day, our low temperatures may dip into th upper 20s and lower 30s, especially in the colder areas away from the warming bodies of water. So, remember to cover those tomatoes and other frost-prone plants.

We should likewise begin to see the arrival of increasing much-needed showers in our part of the country. The stubborn ridge of high pressure that’s brought much drier than normal weather to North Idaho since late June and early July is finally ‘breaking down.’ That’s good news.

Randy and I see above normal moisture across the Inland Empire, again thanks to La Nina, in the next 90 days. The local ski areas should see enough snow later this fall to open for business ‘on time’ around the Thanksgiving holiday weekend. Lookout Pass may actually be able to open prior to Thanksgiving, but only time will tell.

We’ll have more details next week.

SPECIAL NOTE: We wish to extend birthday greetings to long-time Hayden Lake resident Harold Slorp, who turned 106 years young on Sunday, Oct. 10. Imagine, Harold remembers the days before World War I! Wow!

Cliff Harris is a climatologist who writes a weekly column for The Press. His opinions are his own. E-mail sfharris@roadrunner.com