La Nina continues to strengthen in the South-Central Pacific waters

For the last few months, we were in a 'La Nada,' the cycle between the warm El Nino and a cooler than normal La Nina pattern. But now, sea-surface temperatures near the West Coast of South America and along the Equator are cooling at a rapid rate, which would make us declare at least a weak-to-moderate "La Nina" sea-surface temperature pattern.

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.

However, 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., including the Inland Empire, usually receive higher snowfall totals and colder temperatures. This was the case during the winters of 2007-08 and 2008-09 as all-time record snows were reported across much of the northern U.S. and southern Canada. The Maritime Polar Jet Stream becomes more 'loopy' with this pattern, like a piece of spaghetti.

Some subscribers have asked if solar (sunspot) activity were to increase over the next few months, would this counter the effects of La Nina. In the article below, solar activity has increased a bit, but it wouldn't be enough to offset La Nina's influence at this point. If sunspot activity makes a big jump later this year, then it's likely that the winter of 2010-11 wouldn't be nearly as severe as the snowy and cold winters of 2007-08 and 2008-09.

Prior to the late 1990s, it would often take several years for sea-surface temperatures to flip from the El Nino to La Nina. Within the last 10 years, though, we've seen sudden changes from El Nino to La Nina, and vice-versa, sometimes in mere months. This is another example of our cycle of Wide Weather "Extremes," the worst such period in at least 1,000 years.

According to Meteorologist Randy Mann, who will be teaching two Physical Geography courses at North Idaho College beginning next week, the latest sea-surface temperature data indicates that cooler waters are expanding near the West Coast of South America. Ocean temperatures near Ecuador and Peru are now about 3-5 degrees below normal levels and are continuing to show signs of additional cooling.

The Equatorial regions are also cooling down to where some scientists have declared that we have a new La Nina. In fact, there is a strip of cooler-than-normal sea-surface temperatures along the Equator that also is showing signs of intensifying.

The Southern Hemisphere is in the later stages of an unusually harsh winter season, so it's possible that we may see further cooling of the Equatorial waters between now and at least the month of October, probably longer.

If current trends continue, we would likely see an increase the number of tropical storm and hurricane formations by the late summer or early fall season. Ocean waters are much warmer than normal in the Atlantic and Caribbean waters which would enhance tropical storm and hurricane development.

SOLAR STORMS ARE INCREASING A BIT

The cycle from a solar 'minima' to a solar 'maxima' is usually around 11 years. Based on long-term data, the sun is supposed to be heading toward a new solar 'maxima.' But, through May and much of June of 2010, the sun was 'generally quiet.'

Since June 26, however, there have been an average of 10 to 25 sunspots observed daily on the sun's surface. Within the last week, the average number sunspots has increased to nearly 50 per day, the highest reading in years.

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. Many scientists suggest that the upcoming maxima will be very strong, but there hasn't been much evidence yet to support this possible event. However, that could change quickly. Stay tuned for additional updates.

TO ANSWER another Press subscriber's question, 'Sholeh Days' are afternoons when local temperatures reach or surpass 90 degrees. Press columnist Sholeh Patrick, who once lived in hot and humid Houston, Texas, hates hot weather, hence the term 'Sholeh Days.'

NORTH IDAHO'S WEATHER REVIEW AND LONG-RANGE OUTLOOKS

Early this past Wednesday morning, Aug. 11, we gauged .18 inches in less than 40 minutes on Player Drive in town. That was .01 inches more than the .17 inches we had received previously since the rains abruptly quit 40 days before on July 2.

But, high pressure quickly rebuilt across North Idaho later on Wednesday and temperatures were due to return to hot 'Sholeh' levels above 90 degrees by the time one reads this 'Gems' article.

Longer-term, I'm still expecting most of the shower activity in the next six weeks or so, between now and mid-September, to remain in the higher mountains to the west, south and, especially to the north and east of us near the Canadian border and in Montana, where light frosts were reported near Butte on Aug. 12!

The weather prospects for the year's edition of the North Idaho Fair and Rodeo late this month between Aug. 25-29 still look good. I plan to be in the Coeur d'Alene Press booth between 4 and 6 p.m. on Wednesday, Aug. 25, the first day of the popular event.

The annual fall rains should begin as usual in late September and early October, especially if the new cooler and wetter 'La Nina' in the waters of the Pacific Ocean continues to strengthen as predicted. Frosts and freezes will also be possible, even at the lower elevations, by early October.

The upcoming winter of 2010-11 will be MUCH COLDER and SNOWIER than the El Nino-warmed, almost snowless 2009-10 season.

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