The past seven days has dished out just about every kind of weather one could ask for.
First, the record heat. Los Angeles set an all time high temp. record with 113 degrees on Monday, Sept 27, breaking the previous record of 112 degrees on June 24, 1990, and 110 degrees on Sept. 1, 1955 and Sept. 5, 1988. Here in Laguna we made it up to 105 degrees, second only to the 107 degrees way back on Sept. 22, 1939. The water temp. at least on the surface warmed up to 69 degrees, it’s highest reading of 2010.
Meanwhile, down in the Sonora Desert in Northern Mexico, a couple hundred miles south of Arizona, an upper level cutoff low began to intensify a little bit, still a weak system at 1011 millibars (29.83 in.) By midweek, it started to develop a little spin to it while still increasing in strength now at 1008 millibars (29.74 in.). Being an upper level low, it had a lot of cold unstable air at 20,000 feet. This strengthening low began to drift slowly to the north-northwest and by last Thursday, the center was crossing the border near Yuma, Arizona and it had it’s green card. I should note here for those unfamiliar with the term cutoff low. It is a low that has separated itself from the storm track or jet stream along which it follows, which is normally in a west to east fashion, so being cut off from the track, it is free to roam in any direction it chooses, sometimes hanging out in the same general area for a week or more, like the current system.
Later in the week, thunderstorms, some of them bordering on severe status, began to pop up all over Southern California, not just the mountain and desert regions but even in the coastal areas. Laguna only averages six of these type of storm days a year and we had three of them last week alone, half the total in a normal year! By the weekend, the low had intensified even further and the center if it was just east of Las Vegas, with heavy thunderstorms there, the Grand Canyon, Flagstaff and Barstow. And Juiian, where two inches of rain fell in just two hours!
Today, Tuesday, Oct. 5, that same low is still loitering in Southern Nevada with a severe thunderstorm bearing down on Phoenix at 2 p.m., with funnel clouds, quarter size hail, torrential rain, and winds up to 50 m.p.h. and snow already in the Sierras!
October means Santa Ana wind season. More on that next time. Aloha!
Dennis McTighe served as a meteorologist at Hawaii’s Hickam Air Force Base and was an NOAA forecaster. He earned an earth science degree from UC San Diego and has been keeping daily weather records since 1958.