In comparison to last winter, we are starting off the new year on a rather dry note. Our 2010-11 water year (July through June) ended up well above normal, having reached the average rainfall benchmark even before 2011 began. That was a singularity that had never happened before.
But now looking forward to 2012, what can we expect to see in Kern County regarding rainfall and temperature? It is best to consult the eastern equatorial Pacific Ocean to track comings and goings of La Nina, the cooling phenomenon of sea surface temperatures in that part of the world. It has a direct effect on weather patterns worldwide. Last year (2011), La Nina had brought drier weather to most of the state during the bulk of winter. But ocean readings started to warm a bit and by May La Nina event was essentially over. However, sophisticated computer forecasts for the Pacific were calling La Nina back. And as predicted by the models, temperatures started to drop again by autumn. Currently, a moderate cool event is taking place.
La Nina typically brings much drier weather to the southern half of the US, while the northern half is wetter than average. And certainly, no one would mistake the horrific drought that has devastated most of Texas and much of the south from Alabama westward through Arkansas and Oklahoma to New Mexico as being La Nina caused. In many locales the dry spell has been unprecedented. Who can forget those destructive wildfires that blitzed the Lone Star State last summer, and all time heat records. Places like Wichita Fall, Texas soars to 100 degrees or higher nearly 100 days last year. Similar heat duration records were broken throughout Texas. In Bakersfield, we see 100 degrees in a normal year 38 days. Our all-time record is 67 days in 1939. Dozens of cities in Texas broke our all-time heat longevity record, despite their own. Unfortunately, La Nina is back to the detriment of many people from California to Georgia.
And that will be the primary indicating factor for my seasonal forecasts for Kern County.
Here they are: The rest of this winter (2011-12) will be generally dry, but not as cold as December has been. I believe we will see one episode of snow in the south valley, possibly measurable. By March I’m expecting a turn-around in the general pattern to much warmer weather (and still dry). February and March are usually the wettest months of the year, but in 2012 I expect them to fall short of average.
By May and June temperatures will be typically hot, but not excessive. Very little rain will fall, if any during that period. Summer will be hot, of course. I am also forecasting one month, either July or August, to be extremely hot with several days above 112 degrees. Monsoonal thunderstorms should track through eastern Kern County and the Tehachapi mountains in late July and early August, with a couple days threatening the south valley.
La Nina is expected to dissipate by late spring, so the coming autumn should not be directed by that influence. Finally, as the weather begins to turn cooler in late October we will see some initial shower activity that might engender some hope. But it will only be a tease. Warmer than normal temperatures will make Thanksgiving and early December seem more like early October. Close to normal rainfall will return next December, taking an average of December 2010 and December 2011.
So get ready for an overall warmer and drier 2012 in central California. Of course, any drastic changes in sea surface temperatures or unusually stormy activity in the western North Pacific could spell trouble for the forecast. Only time will tell.