Updraft: August 5, 2010 Archive

Return of La Nina may mean a "real" winter

Posted at 4:50 PM on August 5, 2010 by Paul Huttner (1 Comments)
Filed under: Aurora, Climate, Northern lights, Phenology

Soak up all the heat and humidity summer has left folks. La Nina is back.

NOAA's Climate Prediction Center officially confirmed today what meteorologists and climatologists have been watching fo a while, La Nina returned in July.

La Nina is the cool phase of what's known as the El Nino Southern Oscillation (ENSO). Water temperatures in the tropical Pacific Ocean fluctuate every 3 to 5 years between the warm El Nino phase and cool La Nina episodes. The latest readings show sea surface temperatures around -1.0 degree Celsius in much of the tropical Pacific.

La Nina has widespread impacts around different parts of the globe. It can enhance hurricane activity in the Atlantic. Though the 2010 Atlantic Hurricane season has been relatively quiet so far, The National Hurricane Center today updated its seasonal forecast to continue the prediction of an active season.

For Minnesota and much of the USA, the effects of La Nina are most pronounced in winter. La Nina winters have a statistical bias toward being colder than average in the Upper Midwest. Winters can also trend snowier in Minnesota, especially when compared to El Nino winters like last year. The Twin Cities received 40.7" of snowfall last year. The 30 year average is 55.9".

Cricketometer:

Have you noticed how loud the crickets are these nights? It seems as if a cricket boom has hit the weather lab. The deafening roar can be beautiful to some, and annoying to others.

Female (left) an Male (right) crickets image by Jim Mason. Courtesy Great Plains Nature Center web site.

No matter what you think of crickets sounding off at night, you can use the little buggers to approximate the temperature. Here's how:

Count the number of "chirps" in 15 seconds and add 37. That should give you a close approximation of the current temperature in degrees Fahrenheit. This is a fun exercise for kids of all ages on a warm summer night.

My favorite local phenologist Jim Gilbert used to say that cicadas would only sing (sounds more like screaming to me!) when the air temperature reached about 80 degrees. I guess they like the warmth to get those "cicada pipes" in action.

Cicada stands guard Photo credit: Bruce Marlin

One more shot at northern lights?

There may be one last shot of solar wind headed for the earth tonight according to spaceweather.com. Keep an eye out if you are out late tonight for possible auroras in the northern sky. Best viewing is away from lights looking north.

PH

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