30-Day Weather Outlook for February 26, 2018, to March 26, 2018
Summary- The MJO Cycle was heading into an inactive phase on Feb 26. This should discourage development of storms and active fronts into California during March 4-10.
Support continues in the mid-latitude Pacific sea surface temperature field, for high pressure just south of the Aleutians, and increased westerlies into the Pacific Northwest coast and N California during the first part of March.
The El Niño Southern Oscillation (ENSO) continues in the cool (La Niña) phase, but appears to be starting a transition to neutral ENSO conditions. The effect of this is to contribute minimal influence on the subtropical westerlies from the equatorially based ENSO pattern.
In the Near Term – March 1-15… In the southern California avocado growing areas, from San Luis Obispo County to San Diego County, rains are indicated for March 1-3, followed by a drier and warmer days, but cold nights with frosts/freezes about March 5-7. Warmer in general on March 8-9. Another period of rains is suggested by our CFSDailyAI system for March 11-15th with the best chance for rains in San Luis Obispo-Santa Barbara-Ventura Co’s.
Summary – March 16-31… In the southern California avocado growing areas, from San Luis Obispo south, there will be some rains about March 16th and 18-19th, then near or a little below normal rainfall for the remainder of March. Temperatures are coldest on the 20-21st when frost/light freezes are possible in Ventura and Santa Barbara Co’s cold spots. A significant warmup is indicated for March 25-31 in central and S California.
Seasonal Outlook / La Niña Update...April 1 – May 31… Latest solutions suggest above normal rainfall in NW California during the first part of April. Otherwise, near or a little below normal rainfall is suggested for April, with a turn to above normal temperatures.
Going forward into May, the main issue of concern, that will begin to develop in late April and May is unusually warm conditions in late April, followed by a hot May.
After the first week of April, SOCAL appears to turn warmer and drier than normal.
Warm and dry conditions in May continue onward through most of June according to latest CFSv2 and NMME results. When June is warmer than normal, extremely hot days, hottest of the whole year, are most likely to occur, in the SOCAL deserts due to high solar angle and long days.
...Alan Fox, Fox Weather LLC...