WeatherWhys Blog

Sandwich season now officially over

Sandwich season now officially over

It was on November 1st last year that I blogged at this very location we would have a Sandwich Season. Without a doubt, it was a season to remember.

To review, I intended that term to mean: “a rainy season characterized by heavier than average precipitation at that start and end, but with drier than normal conditions in the middle of the season”. November delivered a quarter inch more rain that average, but December dumped 5.82” of rain in Bakersfield. That is more than 5 inches above average or 766% of normal and, as it turned out, was the wettest month of all time in Bakersfield (records go back to 1889). We actually bagged our normal water year rainfall BEFORE the end of the calendar year. That had never happened before. Then January and February fell below average by about ¾ of an inch each of those months. March is usually the wettest month of the year and there was a spike of precipitation due to a potent polar jet stream and some thunderstorm activity. We had 1.67” in March 2011, which was about a quarter inch above the expected rainfall. In April and May it appeared our rainy season was over, but several late systems provided about a quarter inch of rain those months and in May the .23” was only .01” below normal.

This past weekend an impressive weather system spun down the west coast looking like something you might see in January or February. It was a very photogenic storm on satellite imagery and brought extremely heavy rain to parts of the San Joaquin valley with more than 1.50 inches falling in the Fresno area. While Bakersfield only officially reported .08”, Wasco picked up .77” and Delano recorded exactly half an inch. Tremendous for June! Through Wednesday the average temperature for the month of June was 10 degrees below normal. If this trend were to continue through the end of June, it would easily be the coolest June of record (which occurred in 1923 when the mean temperature was only 69.7 degrees). So far this month the mean has only been 65.1 degrees. But that is about to drastically change.

Our weather pattern has been cool due to an anomalous area of high pressure in southern Canada. This feature has caused the polar jet stream to be diverted much farther to the south. However, computer models have indicated that the minor ridging in Canada has dispersed. In fact, a wholesale change for the northern hemispheric pattern is underway. Blazing hot temperatures for half the nation (103 in Minneapolis, for example) are finished. High pressure over the central and eastern US, which has balanced the unseasonably cool weather here in the west, has shifted position. Now high pressure aloft will move to the southwestern US with a break in the torrid conditions for the central plains and Mississippi Valley. While they cool off, we will warm up. Temperatures near normal are forecast for the next few days in Kern County with a slight cooling over the weekend. But next week (in the middle of June) I am predicting we will experience our first triple digit weather for the summer. Actually, summer doesn’t officially begin until Tuesday the 21st at 10:16 AM. But it will seem like summer next week.

This leads to my summer forecast. In the past, whenever a cool and wet spring have proceeded into June, there has generally been a quick shift from cool to hot, wet to bone dry. That is what I’m expecting this summer. Whereas it has been wonderfully cool for your PGE bill, that too will change. The month of June is expected to end slightly below normal, because the first 8 days have been so exceedingly cool. But July and August are forecast to be hotter than normal with an active monsoonal season beginning in late July and running through mid September. It will be hot in September as well.

So I hope you have enjoyed our Sandwich Season. Now get ready for some good ole’ fashioned central California heat, complete with at least 5 heat waves. After all, our cool “June-uary” is over and they don’t call it “Bake”-ersfield for nothing.