46 Analysis of mesoscale rapidly occluding storm causing severe atmospheric anomalies in Southern California on February 28th, 2014

Monday, 15 June 2015
Meridian Foyer/Summit (The Commons Hotel)
Alejandro A. Mundo, California State Polytechnic University, Pomona, Pomona, California

Handout (24.2 MB)

There are always good compliments on California's weather because no matter the season of the year a pleasant atmosphere usually prevails, until an alarming event changed the life course of 22 million of Southern Californians. On February 28th, 2014, Southern California experienced the largest thunderstorm since the storms of December 2010. The continuous progressivity of a strong and rapidly-occluding storm off the coast of California roaring from the Pacific Ocean led to flash flooding including mud and debris flows in certain zones. In order to understand the tough effect this storm had upon the zone, time-series of 125 NWS and RAWS weather stations are tested including at least 80% of hourly observations for a period of 72 hours. Analysis show the peak precipitation in the San Diego, Orange, Los Angeles and San Bernardino counties where precipitation reached 6 inches in various parts. The substantial amounts of extreme precipitation were along the southern slopes of the San Bernardino County mountains, with Yucaipa Ridge reaching 11.11 inches, Lytle Creek with 9.67 inches and Cedar Glen with 9.10 inches. The occluding storm off Southern California's cost led to continuous flash flooding and winds of up to 77mph in different zones. An indication of the strength of the storm was the high amount of GOES-15 sounder Total Column Ozone associated with its circulation, which reached levels as high as 440-450 Dobson Units. These findings imply that the high levels of total column ozone are associated with potential vorticity anomalies and a dramatically lowered tropopause. Additional numerous arc-shaped mesospheric airglow waves in the storm circulation suggest that a 140-knot jet streak propagated them vertically in the southward direction.
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