A weather winter storm warning was issued for high elevations of the Big Island of Hawai'i as CIMSS analysis by Tim Wagner showed abundant moisture and strong upper level support for snow at summit heights.
CIMSS imagery indicated an atmospheric river linking the continental United States to the equator with nearly two inches of precipitable water available, and GOES 18 water vapor imagery revealed a sharp upper level trough driving dynamic lift.
Band 13 infrared wind imagery and the day cloud phase distinction RGB highlighted deep, cold cloud tops in the ice phase, signaling active snow formation at high elevations above the freezing level.
The 1200 UTC Hilo sounding obtained from the University of Wyoming Radiosonde Archive showed a deep saturated layer from the surface to above 400 mb and a freezing level at 640 mb, about 3,900 meters, below Mauna Kea's summit elevation.
NUCAPS gridded temperatures placed 700 mb near freezing over the island, but retrieval quality was degraded where clouds were thick, with many profiles flagged red and likely error prone, according to the CIMSS account.
The local National Weather Service office issued the winter storm warning for the high elevations of the Big Island, and the CIMSS write up noted archives at the Iowa Environmental Mesonet show most years include at least one noteworthy snow event in Hawaii.
The CIMSS post was dedicated to NOAA NWS Honolulu meteorologist and UW Madison alumnus Will Ahue, described as a native Hawaiian and colleague who recently passed away.
Yosemite Warning And Public Guidance
An updated winter storm warning from NWS Hanford CA was released at 8:08 p.m. on Monday and is valid from 10 p.m. until Wednesday Feb. 11 at 4 p.m., with the heaviest snow expected Tuesday evening into early Wednesday morning.
The NWS forecast calls for total snow accumulations of 12 to 18 inches above 7,000 feet and up to 24 inches at the highest elevations, with winds gusting as high as 40 to 50 miles per hour.
NWS Hanford warned travel could be very difficult to impossible, and hazardous conditions could affect Tuesday morning and evening commutes, with gusty winds able to bring down tree branches.
All enabled mobile phones in the San Francisco Bay Area will receive emergency alerts for considerable or catastrophic hazards, and residents are advised to sign up for county alert systems and monitor agencies' social media.
Local guidance lists county resources for alerts and shelters, including Santa Clara's Overnight Warming Location program, Alameda County's shelter list from Alameda County Health Care for the Homeless, San Mateo's Inclement Weather Program access through Core Service Agencies, Contra Costa's 211 and shelter lists, and Solano County centers where people can keep warm.
NWS Hanford offered winter driving advice: slow down, assume icy patches, avoid driving if possible, choose routes with fewer trees and power lines, and never touch a downed power line, calling 911 instead.
The agency also advised motorists to share travel plans, keep their gas tank full, and carry essentials such as a windshield scraper, jumper cables, a small shovel, flashlight, cell phone, blanket, extra warm clothing, drinking water, and non-perishable food.
If stranded, NWS recommends staying calm, notifying others of your location, avoiding walking to safety, attaching a cloth to the vehicle antenna or mirror to signal for help, using interior lights and flashers to increase visibility, and yielding to snow plows.
