####018006415#### ACUS43 KWBC 060255 SCCNS3 Storm Summary Number 2 for West Coast Multi-Hazard Atmospheric River Events NWS Weather Prediction Center College Park MD 700 PM PST Thu Jan 05 2023 ...Heavy rain/snow and high winds subsiding across California as the next Atmospheric River arrives on Friday... Flood Watches are in effect for much of the Central Valley of California . High Wind Warnings and Wind Advisories are in effect for portions of California and Oregon. Winter Storm Warnings are in effect for portions of the Sierra Nevada, Transverse Range, and western Nevada. Winter Weather Advisories are in effect for portions of the Transverse Range and central Nevada. For a detailed graphical depiction of the latest watches, warnings and advisories, please see www.weather.gov At 600 PM PST...A low pressure center was analyzed over 300 miles northwest of the Washington coastline with a minimum pressure of 976 mb (28.82 in Hg). Latest surface analysis depicted a dying occluded front that extended to the southeast of this low into the Pacific Northwest and Great Basin, to a triple point located just north of Las Vegas. From the triple point, a cold front extended to the south through southern California, while a warm front was analyzed across Arizona. Latest surface observations and RADAR depicted improving conditions across the California coastline, as the heaviest precipitation was confined to the Sierra Nevada Range due to upslope flow enhancing rainfall/snowfall rates along the higher terrain. Outside of higher terrain, lingering onshore flow continued to produce isolated light to moderate rain along coastal portions of California, with the greatest coverage in the northern region of the state. Precipitation ahead of the frontal boundary had also begun to push eastward into the Intermountain West with ongoing light to moderate rain/snow along a north-south axis from southern Idaho into Arizona. ...Selected preliminary Storm Total Snowfall in inches from 700 AM PST Wed Jan 04 through 600 PM PST Thu Jan 05... ...CALIFORNIA... JUNE MOUNTAIN SKI BASE 18.0 MAMMOTH MOUNTAIN SKI BASE 16.0 HEAVENLY SKI BASE 12.0 HETCH HETCHY 10 NE 12.0 MT ROSE SKI BASE 12.0 ...Selected preliminary Storm Total Rainfall in inches from 700 AM PST Wed Jan 04 through 600 PM PST Thu Jan 05... ...CALIFORNIA... OLD MAN MOUNTAIN 6.54 CALFIRE 5.66 THREE PEAKS 5.24 FRENCH GULCH 5.13 LOS GATOS 4.17 BURLINGAME 2.0 WSW 2.96 MORAGA 2.4 NNW 2.85 UKIAH MUNICIPAL APT 2.64 K6BPM SANTA BARBARA 2.36 ROHNERT PARK 0.9 SW 2.30 ATASCADERO 2.3 NE 2.13 THOUSAND OAKS 2.1 WSW 2.02 SACRAMENTO INTL APT 1.84 SAN FRANCISCO INTL APT 1.81 LOS ANGELES INTL APT 1.51 HOPLAND 8 SSE 1.50 OXNARD NWS 1.46 SANTA BARBARA MUNICIPAL APT 1.19 ...Selected preliminary Peak Wind gusts in miles per hour earlier in the event... ...CALIFORNIA... KIRKWOOD MEADOWS 1.2 S 119 GRAPEVINE 3 SSE 104 PULGA 2 NNW 102 PABLO POINT 101 YORKVILLE 5.5 NW 95 CAPETOWN 6 ENE 94 COBB RIDGE WEST 91 ROAD TO RANCHES 90 HIGH GLADE LOOKOUT 89 FERNDALE 6.4 S 88 MAGIC MOUNTAIN TRUCK TRL 87 AMERICAN HOUSE 6 NW 84 AGUA DULCE 8 S 81 BIG BEAR CITY 13 ESE 72 MOUNTAIN GATE 3 NNE 72 CRESCENT CITY 1 ESE 69 JULIAN 9 S 65 BLACK MOUNTAIN 7 E 64 The low pressure center and associated frontal boundaries will continue to weaken through tonight, with precipitation diminishing across California. Areas where showers persist the longest could see an additional 1"+ of rainfall through the morning hours, while the higher elevations of the Sierra Nevada and Klamath ranges may see another 6-12"+ before snowfall ends. As the impacts from this event will shift eastward as the system disorganizes and dissociates across the eastern Pacific Ocean, the next atmospheric river event is forecast to arrive late Friday into northern California, before spreading southward to the central portion of the state on Saturday. The cumulative effect of an additonal several inches of rainfall after recent precipitation will lead to considerable flood impacts this weekend, including rapid water rises and mudslides over northern and central California. Flash flooding and debris flows are possible over burn scar areas. Furthermore, an additional 1-2 feet of snow this weekend will lead to dangerous travel above 5000 feet in the higher terrains of northern and central California. The next Storm Summary will be issued by the Weather Prediction Center at 700 AM PST. Please refer to your local National Weather Service office for additional information on this event. Russell $$