San Diego is inching toward its wettest May on record as a Pacific storm more common for January is bringing heavy rain — and even snow — to the drought-stricken Southwest.  On Thursday, San Diego International set a record for wettest day in May after totaling 1.63 inches of rain. The previous wettest May day was May 8, 1977, when 1.49 inches fell.  As the rain continues on Friday, the city is staring down a bigger record for wettest May. The previous record-wet May was in 1921, when 2.54 inches fell. As of noon on Friday on the West Coast, San Diego’s 2-day rainfall total was up to 1.8 inches, and the total for the month was 2.32 inches.  San Diego is not a wet city, especially in May. “Our long dry season usually begins in May, and the average number of days with measurable rain is 2, with an average monthly total of 0.2 inches,” says the National Weather Service. “Stormy weather is almost unknown during the month.” May rainfall has exceeded two inches only three other times in San Diego records.  In addition to the winter-like rain, the storm was also bringing winter-like white to the high elevations in Southern California and Arizona. The Flagstaff National Weather Service office, located in Bellemont, Ariz., totaled 7.7 inches of snow this morning. Hart Prairie, Ariz., saw 9 inches, and Parks, Ariz., saw 6 inches.  [Strengthening El Nino fuels record-warm start to the year]  The National Weather Service says the last time they saw heavy snow this late in the season at Flagstaff Airport was 2008, when 4.4 inches fell on May 23. They go on to say that Flagstaff has seen snowfalls greater than 3 inches on or later than May 15 on only five occasions.  Angela Fritz is an atmospheric scientist and The Post's deputy weather editor.
The storm, which is very uncommon for May, also brought snow to the high elevations of Arizona on Friday.