Goodbye rain, hello JPL

Posted on | March 23, 2010 | No Comments

NASA's Earth Observatory captured this image of a large storm over the California coast on January 20th, 2010. This Friday and Saturday, March 26-27, the Jet Propulsion Laboratory in La Canada Flintridge will be hosting two Climate Days in which scientists from NASA and the National Oceanic and Atmospheric Administration will explain to classes and members of the general public the effect of greenhouse gases and clouds on climate, the difference between weather and climate, the role of the ocean in global warming and how scientists study Earth's climate from space. Attendees may participate in hands-on activities, view exhibits, demonstrations, student presentations, play Climate Jeopardy and other games, and get information on careers and resources for teachers and community members. Click on the Pacific storm for more information.

The meteorologist/blogger Bad Mom, Good Mom recently copied me in on a query to Jet Propulsion Laboratory oceanographer Bill Patzert: “It looks like the Pacific high is nearly stationary offshore from us,” she wrote. “No rain thru 3/27 (and probably longer) … is it here to stay for the rest of the spring & summer?”

Patzert replied, “After the Vernal Equinox (last Saturday, March 20th), the Northern Hemisphere begins to rapidly warm up. This expands the North Pacific High and shrinks the North Pacific Low.  As the High expands and strengthens, storms weaken and go farther to the north of California. Also, winds from the north (the eastern segment of the High) get stronger and upwelling along our coast picks up. Cooler water, more marine layer; thus, May gray and June gloom.  The High is strengthening, northerly winds are becoming steadier, there is more coastal and inland fog, and no North Pacific storms … our dry six months.

The upshot for those of us reading the exchange between the two scientists is that the 2009/10 rainy season is ending in Southern California. The precipitation total so far this rainy season for downtown Los Angeles is just shy of normal at 14.66 inches. The average reckoned between 1971 and 2000 is 15.24 inches. The average rainfall for March is 3.14 inches; so far this month we have received .48 inch. “We had early rain in October,” said Patzert. “Usually a wet fall means a dry spring. I don’t see anything over the horizon, but April could surprise us.”

Los Angeles rain gauge:

2009: October 2.07”; November .01”; December: 2.89”

2010: January 4.94”; February 4.27”; March .48”

Click here for NOAA’s online weather data page. Or for an excellent educational foray, click here to be taken to Bad Mom, Good Mom’s feature “Walking my Watershed.”


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