Deep Surface Low Pressure

The major winter storm slamming into the west and dropping feet of snow in the Sierra might set a record for lowest surface pressure in an extra-tropical cyclone (1) (2) (fancy name for low-pressure system) measured in the united states. If it maintains its current central pressure of 958 mb it will break the old record of 960 mb set in March of 1993 (The Storm of the Century (1) (2) (3)). It will also be stronger than "The Perfect Storm" of October 1991.

Although this is deep, extra-tropical cyclones frequently get this strong over the open Northern Atlantic and Pacific but rarely maintain such strength as they move on land. The record for lowest surface pressure in the Atlantic was set by category 5 Hurricane Wilma (1) (2) in 2005 at 882 mb and the record for lowest surface pressure in the Pacific was set by Super typhoon Tip in 1979 at 870 mb (Tip was also largest tropical cyclone ever).

The image below is a map of mean sea level pressure. The deep low-pressure system off the coast of Washington is the current storm that will be bringing 3-6 feet of snow to the Sierra and Cascade Mts. Check out this NWS page for all of the blizzard warnings! With such a deep low-pressure center in the west and a strong 1040 mb high-pressure center in the southeast, C-U will get strong winds out of the south due to the clockwise circulation around the high. This means a huge warm up over the weekend but it will be wet!