A warm pool of water in the central and eastern tropical Pacific has been finally designated as a weak El Nino by the Climate Prediction Center (Feb. 14), slowly building, but much weaker than the record El Nino in 2015-16.
An atmospheric river (plume of moisture) linked to tropical forcing jhas been fueling storms that have pounded the West Coast, before moving cross-country in recent weeks.There may be a little extra energy from El Nino in the mix.
The pattern has kept Ohio unusually damp and dreary for February, with bouts of high winds and even a few thunderstorms.
So far this month, 5.34 inches of precipitation has fallen in Columbus, more than 3.5 inches above normal–the seventh wettest February on record since 1879. February 2018 was also wet (5.25 inches).
The subtropical branch of the jet stream has provided energy for southern storms, while also largely blocking polar air — except when the pattern flips as it did in late January, allowing a lobe of the polar vortex to plunge Ohio into subzero frigid temperatures.
As storms travel down the coast of California, polar air has been inflicting winter in cities from Seattle to Las Vegas, where snow is not common. On Thursday, snow covered the highways north of Los Angeles, including 5 Freeway through the Grapevine, bringing traffic to a halt, and flurries dusted parts of the metro area.
Snow levels dipped to 1,000 feet, and snow dusted the ground at Palmdale. Snowflakes were seen in Pasadena and West Los Angeles, and areas between Malibu and Simi Valley. The higher elevations of the San Gabriel Mountains in Los Angeles County picked up a half-foot of snow.
Flagstaff, Arizona, recorded a one-day record snowfall of 35.9 inches Thursday, in the northern mountains (39.8 inches from Feb. 20-22). Areas around Los Angeles and Phoenix saw a few flurries, with light accumulations in Los Angeles County at elevations of 700 to 1,100 feet. Flurries even reached the coast at Malibu Pier.
Las Vegas, Nevada, saw snow for the third time this week, with substantial accumulations over higher terrain. Former Columbus resident, Don Berman, sent me a photo of the 5- to 7-inch snowfall cloaking Summerlin, in the northwest city limits.
The official NWS total is taken at McCarran Airport at a lower elevation, where 0.8 inch fell Wednesday and Thursday. A trace of snow was recorded there on Feb. 10 and Feb. 17-18.
The latest dusting of snow in Las Vegas fell on Feb. 25, 1987. So snow so late in the winter is a rarity.
The last measurable snow in the city came on Dec. 17, 2008 (3.6 inches). Records extending back to 1937 show recurring February snowfalls only twice — the last time was in 1949.