Summary of the February 21, 2009 Winter Storm (Updated 2/22)

A strong upper level disturbance originating in Alberta, Canada tracked southeast into the Upper Mississippi River Valley overnight on February 20th. Meanwhile, a surface low pressure system developed over Missouri which tracked northeast across far southeast Wisconsin (between Milwaukee and Racine) on the afternoon of the 21st. 

Below is an animation of infrared imagery of the storm, with isobars and the track of the surface low superimposed.

Infrared imagery of the Feb 21st winter storm.

Below is a radar animation of the storm.

Radar animation of the storm.

Widespread snow associated with this complex system overspread southern Wisconsin after midnight on the evening of the 20th and continued through the early evening of the 21st. Widespread snowfall amounts of 5 to 8 inches were observed, with the heaviest amounts over southeast Wisconsin. 

Snowfall map of southern Wisconsin.

Some of the higher totals of the event are listed below:

INCHES  LOCATION                 COUNTY          SOURCE     
------  -----------------------  --------------  ----------------- 
  8.8    1 N WEST BEND            WASHINGTON      SPOTTER
  8.7    1.8 SE WAUKESHA          WAUKESHA        COCORAHS
  8.5    ALLENTON (WWTP)          WASHINGTON      COOP
  8.5    1 NW BELGIUM (WWTP)      OZAUKEE         COOP
  8.0    4 S SHEBOYGAN (WWTP)     SHEBOYGAN       COOP
  8.0    WAUKESHA (WWTP)          WAUKESHA        COOP
  8.0    2 ESE WAUKESHA           WAUKESHA        COOP/NWS EMPLOYEE
  7.8    1 SW ELKHART LAKE        SHEBOYGAN       COOP
  7.8    WEST ALLIS               MILWAUKEE       COOP
  7.7    RICHFIELD                WASHINGTON      COOP
  7.4    LAKE MILLS               JEFFERSON       COOP
  7.4    5 SW MADISON             DANE            SPOTTER  
  7.3    WISC-TV3 MADISON         DANE            MEDIA
  7.3    2 NW FRANKLIN            MILWAUKEE       SPOTTER
  7.3    WATERTOWN (WWTP)         JEFFERSON       COOP
  7.0    SHEBOYGAN (SOUTHWEST)    SHEBOYGAN       COOP
  7.0    BLANCHARDVILLE           LAFAYETTE       COOP
  7.0    2 E HOLY HILL            WASHINGTON      COOP     
  7.0    1.1 S WATERTOWN          JEFFERSON       COCORAHS

Steve Davis and Bill Borghoff

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