CW3E AR Update: 5-6 March 2016 Post-Event Summary

March 10, 2016

CW3E gives a post-event storm summary about a moderate strength Atmospheric River that made landfall over Northern California on 5 March 2016. The AR was an R-Cat 1 event and produced over 10 inches of 72-hour precipitation.

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Northern Sierra Precipitaiton: 8-Station Index

~7.5 inches of precipitation measured by the 8-Station Index

Increased water-year-to-date accummulation from average to ~115% of average

Lake Mendocino Storage

Increase in storage of ~8000 af

Storage remains above the Target Water Supply Storage Curve

SSMI Integrated Water Vapor: 0000 UTC 3 March – 0000 UTC 7 March

  • AR developed over the Central North Pacific and made landfall over Northern California
  • AR entrained moisture from previous decaying AR off California coast prior to landfall

GFS IVT Analysis: 0000 UTC 3 March – 1200 UTC 7 March 2016

Cazadero, Ca Snow Level Radar

Heavy bright-band precipitation began ~0600 UTC 5 March

Large drop in snow level post-frontal

Bodega Bay 0200 UTC Sounding

  • Saturated atmosphere up to ~550 hPa
  • IWV = 31.9 mm
  • IVT = 878.3 kg m-1s-1
  • Winds >50 knots throughout the troposphere
  • Majority of water vapor flux between 950-700 hPa

Event Summary

  • A moderate strength Atmospheric River made landfall over Northern California during 5-6 March 2016
  • Maximum 48-h precipitation of >10 inches occurred over the Sierra Nevada
  • Widespread precipitation >6 inches occurred over the Coastaland Sierra Nevada Ranges
  • Several rivers reached above flood stage in Northern California