Daily Blog, 11/6/09: Coleman's Comments
November 6, 2009 The official drought monitor map still shows California in a drought. No surprise about San Diego being there. After all, we have had no measurable rain for 142 days. And, no surprise the rest of the state is there as well because La Nina weather pattern of the last three years has not been a great rain and snow maker. But remember that last winter, the Sierra snowpack was normal or higher and the big October storm...well it was a monster. The National Weather Service has just documented that rainstorm and how and why it drenched most of California in mid-October. Here is their map of rainfall totals for the storm. Here is the report by Miguel Miller from the NWS San Diego Newsletter: The Hunt for Wet October An October storm like we haven’t seen in five years brought copious amounts of rainfall to Northern and Central California, and part of Southern California on 13 and 14 October. In the coastal mountain ranges of Central California (near Big Sur) the top rainfall amounts exceeded 21 inches for this storm. Some areas received about half of their normal seasonal rainfall in two days! San Francisco recorded their wettest October day on record with 2.48 inches on 13 October. The city boasts the longest rainfall record in the state, dating back to the Gold Rush in 1849. In contrast, San Diego received no rain. Why did the rain miss far Southern California when the rest of the state got pummeled? The graphic below shows the strong jet stream directing a lot of energy... ...and a lot of moisture into the northern three-quarters of the state. Where the jet noses into the west coast, enhanced rainfall occurs on the north side of the jet while suppressed rainfall occurs on the south side (the opposite is true at the tail end of the jet). In addition, the moisture in the atmosphere was very deep and plentiful north of about Los Angeles, and very shallow and scarce to the south. It was a strange contrast, but not shocking. There were some flooding problems, but largely the rain was welcome after the long dry summer and it was beneficial as it brought an end to the fire season for much of the state. Luckily, the rain rate over the massive Station Fire burn area was not great enough to cause widespread flooding or large debris flows. If the moderate El Nino will now just bring us normal rainfall for the winter, the drought should be history. Meanwhile, the state legislature has passed a huge bond issue deal with water. I note it does nothing to get more water, doesn't import more, make more rainfall or encourage desalination (for instance) but just does the various water districts pet projects. I am an old main and can be grumpy. I yearn for vision and leadship at all levels of bureaucracy and from our politians and I am constantly left mumbling and shaking my head. John Coleman To send me an email, click here. |
