Winter Storm - February 20th-21st, 2013

National Weather Service, Springfield, MO

Summary

Synopsis

Maps

Radar

Reports

Event Summary

A strong storm system affected much of the central U.S. including the Missouri Ozarks and extreme southeast Kansas from the evening hours on February 20th through much of the day on February 21st. Blizzard conditions affected parts of the Plains in Kansas into northwest Missouri, while across the Missouri Ozarks and southeast Kansas, a wide variety of winter weather occurred. Much of the area began with some light snow and changed over to a mix of sleet and freezing rain as warmer air moved in above the surface. Elevated instability led to numerous embedded thunderstorms which produced heavier rounds of sleet and freezing rain across the area. Across the Missouri Ozarks and southeast Kansas, 1-2 inches of a sleet and snow mix were common along with a quarter to half inch of ice. Further north across portions of west central and Central Missouri, snow was more common and 3 to 5 inches of snow occurred there.

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Event Synopsis

A strong dynamic storm system affected the Missouri Ozarks into southeast Kansas mainly during the overnight hours and through the day on February 21st, 2013. This storm system brought a wide variety of winter weather including thunder, freezing rain, sleet and snow to the region.

Dry and cold antecedent conditions led to a later onset of precipitation in the Ozarks which began as snowfall.

From the 6 pm sounding above, you can see the very dry air (green is the dew point, red is the temperature) in the lower levels that had to moisten up before precipitation would reach the ground. The initial precipitation falling was evaporating in this dry layer but also cooling the air in this column via a process called evaporative cooling.

By the midnight sounding (above), you can see the mid levels of the atmosphere had moistened up quite a bit but it was still pretty dry (although moistening) in the lower levels.

There is a lot going on here in the final 6 am sounding shown above. First of all, notice that the low levels continued to moisten overnight. Warmer air above the surface was advected in from the strong south to southwest winds with temperatures up to 4 degrees Celsius (39 deg F) within the warm nose. The helped to melt the snow as it was falling from above and then fall back to the below freezing temperatures at the surface for freezing rain. There was also enough elevated instability above the warm nose of air to promote thunderstorm development within the precipitation. Sleet became heavy at times during the bouts of thunder during the day.

Eventually during the afternoon, drier air in the mid and upper levels of the atmosphere worked into the area from the southwest and helped push the bulk of the precipitation to the east. Some moisture wrapping around the low brought some freezing drizzle to the area during the evening into parts of the overnight hours of the 22nd.

Event Radar

Below is a radar composite loop from the Springfield radar each hour from Midnight through 9 pm on Feb 21st 2013.

Event Maps

This product is an objective analysis of NWS Cooperative Observer Program (COOP) and Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) snowfall reports. CoCoRaHS data is from non-NWS sources and may have not been fully quality controlled.

Event Reports
THE TOTALS BELOW ARE SEPARATED INTO SNOW...AND ICE AND SLEET
CATEGORIES...THEN BY AMOUNT...AND ARE NOT NECESSARILY THE
FINAL AMOUNT FOR EACH LOCATION.

SNOW REPORTS LISTED BY AMOUNT

INCHES LOCATION                 ST COUNTY           TIME
------ ----------------------- -- --------------   -------
5.00   VERSAILLES               MO MORGAN           0920 PM
                 STORM TOTAL. COUNTY DISPATCH ALSO REPORTED 4
                 TO 5 INCHES OF SNOW. A QUARTER INCH OF ICE
                 ALSO REPORTED.
3.00   APPLETON CITY            MO ST. CLAIR        1033 AM
                 THREE INCHES OF SNOW AND SLEET ON THE GROUND.
2.50   WARSAW                   MO BENTON           1020 AM
                 TWO TO THREE INCHES OF SNOW ON THE GROUND
                 WITH SOME SLEET MIXED IN.
1.50   FORT SCOTT               KS BOURBON          0910 AM
                 ADDITIONAL 0.60 INCHES OF SLEET. CURRENTLY
                 RAINING THOUGH.
0.50   10 W VICHY               MO MARIES           1042 AM
                 ONE HALF INCH OF SNOW AND SLEET REPORTED.

SLEET AND FREEZING RAIN REPORTS LISTED BY AMOUNT

INCHES LOCATION                 ST COUNTY           TIME
------ ----------------------- -- --------------   -------
3.00   FORT SCOTT               KS BOURBON          1013 AM
                 THREE INCHES OF SLEET ON THE GROUND. SOME
                 SNOW MIXED IN.
3.00   VIENNA                   MO MARIES           0136 PM
2.50   MARSHFIELD               MO WEBSTER          0329 PM
                 SLEET THIS MORNING ACCUMULATED TO AROUND 2
                 INCHES IN MARSHFIELD AND AS MUCH 2.5 INCHES
                 IN SOME PARTS OF THE COUNTY.
2.00   GRAVOIS MILLS            MO MORGAN           1001 AM
                 TWO INCHES OF SLEET ON THE GROUND. SMALL
                 AMOUNT OF SNOW MIXED IN.
2.00   GRAVOIS MILLS            MO MORGAN           1005 AM
                 TWO INCHES OF SLEET ACCUMULATED ON THE
                 GROUND.
2.00   DIXON                    MO PULASKI          1052 AM
                 TWO INCHES OF SLEET ON THE GROUND. SOME SNOW
                 MIXED IN.
2.00   CAMDENTON                MO CAMDEN           1120 AM
                 TWO INCHES OF SLEET ON THE GROUND.
2.00   BOLIVAR                  MO POLK             0113 PM
2.00   SALEM                    MO DENT             0241 PM
                 1.5 TO 2 INCHES ACCUMULATION.
2.00   NIXA                     MO CHRISTIAN        0324 PM
                 HEAVY PRECIPITATION OCCURRED THIS MORNING.
                 ALSO A TENTH TO A QUARTER INCH OF ICE.
1.75   WALKER                   MO VERNON           0942 AM
                 ONE AND THREE QUARTERS INCH ACCUMULATION OF
                 SLEET AND HAIL ON THE GROUND.
1.50   JOPLIN                   MO JASPER           0908 AM
1.50   CROSS TIMBERS            MO HICKORY          1023 AM
                 THREE QUARTERS OF AN INCH OF SLEET ON THE
                 GROUND.
1.50   WAYNESVILLE              MO PULASKI          1137 AM
                 ONE AND ONE HALF INCHES OF SLEET ON THE
                 GROUND.
1.50   JOPLIN                   MO JASPER           1218 PM
1.50   MOUNT VERNON             MO LAWRENCE         0335 PM
                 AN INCH TO AN INCH AND A HALF OF SLEET.
1.25   ROLLA                    MO PHELPS           1107 AM
                 ONE AND ONE QUARTER INCHES OF SLEET. THIN
                 GLAZE OF FREEZING RAIN ALSO.
1.25   IBERIA                   MO MILLER           1123 AM
                 THIN GLAZE OF ICE.
1.25   WAYNESVILLE              MO PULASKI          0201 PM
                 ADDITIONAL 0.25 INCHES SINCE NOON. TOTAL 1.25
                 INCHES.
1.00   RICHLAND                 MO PULASKI          1010 AM
                 ONE INCH OF SLEET ON THE GROUND.
1.00   5 N SENECA               MO NEWTON           1016 AM
                 ONE INCH OF SLEET WITH A GLAZE OF ICE.
1.00   LAMAR                    MO BARTON           1043 AM
                 ONE INCH OF SLEET ON THE GROUND.
1.00   3 NE HALLTOWN            MO GREENE           1208 PM
                 MEASURED ONE INCH OF SLEET ACCUMULATION AND
                 ONE EIGHTH INCH OF ICE ACCRETION.
1.00   WAYNESVILLE              MO PULASKI          1215 PM
                 ONE INCH OF SLEET AND ONE EIGHTH TO ONE
                 QUARTER INCH OF FREEZING RAIN REPORTED.
1.00   6 NE WILLARD             MO GREENE           0100 PM
                 ALSO ABOUT A TENTH TO TWO TENTHS OF AN INCH
                 OF ICE.
1.00   EMINENCE                 MO SHANNON          0230 PM
                 COMBINED SLEET AND ICE ACCUMULATION.
1.00   AVA                      MO DOUGLAS          0231 PM
                 ALSO...0.1 INCH OF FREEZING RAIN ACCUMULATION
                 ON EXPOSED OBJECTS.
1.00   WINONA                   MO SHANNON          0235 PM
                 COMBINED HALF INCH TO AN INCH OF SLEET AN
                 ICE. MOSTLY SLEET.
1.00   BRANSON                  MO TANEY            0255 PM
                 RANGED FROM AN A HALF INCH IN THE SOUTHERN
                 PART OF TANEY COUNTY TO AN INCH IN THE
                 NORTHERN PART OF THE COUNTY. A TRACE OF ICE
                 ACCUMULATION.
1.00   MARSHFIELD               MO WEBSTER          0330 PM
                 ONE HALF INCH TO ONE INCH OF SLEET
                 ACCUMULATION COUNTY WIDE.
1.00   6 S SPRINGFIELD          MO GREENE           0347 PM
                 ONE INCH OF SLEET AND A QUARTER INCH OF ICE
                 GLAZED ON TREE LIMBS.
0.75   SARCOXIE                 MO JASPER           0732 AM
0.75   BUFFALO                  MO DALLAS           0851 AM
                 THREE QUARTERS OF AN INCH OF SLEET AND HAIL
                 ON THE GROUND. ONE EIGTH INCH OF ICE
                 ACCUMULATION.
0.75   PITTSBURG                KS CRAWFORD         0853 AM
0.75   CASSVILLE                MO BARRY            0313 PM
                 SLEET ACCUMULATION OF A HALF INCH TO THREE
                 QUARTERS OF AN INCH. JUST A GLAZE IN THE
                 TREES.
0.70   HERMITAGE                MO HICKORY          0716 AM
                 THREE QUARTERS OF AN INCH OF SLEET REPORTED
                 ON THE GROUND.
0.70   6 WSW JOPLIN             MO NEWTON           0800 AM
                 THREE QUARTERS OF AN INCH OF SLEET REPORTED
                 ON THE GROUND NEAR THE TRI STATE LINE.
0.70   BUFFALO                  MO DALLAS           0851 AM
                 THREE QUARTERS OF AN INCH OF HAIL AND SLEET
                 ON THE GROUD. ONE EIGHT INCH OF ICE
                 ACCUMUATION.
0.60   2 WNW SPRINGFIELD        MO GREENE           1120 AM
                 MEASURED 0.6 INCHES OF SLEET AND SMALL HAIL
                 AT NWS OFFICE.
0.50   OSCEOLA                  MO ST. CLAIR        0707 AM
                 HALF INCH OF SLEET REPORTED ON THE GROUD.
0.50   BOLIVAR                  MO POLK             0742 AM
                 HALF INCH OF SLEET REPORTED.
0.50   10 W SPRINGFIELD         MO GREENE           0946 AM
                 ONE HALF INCH OF SLEET ACCUMULATION. ONE
                 EIGHTH INCH OF ICE ACCUMULATION.
0.50   WEST PLAINS              MO HOWELL           0153 PM
0.50   GAINESVILLE              MO OZARK            0255 PM
                 ESTIMATED A COMBINED QUARTER TO HALF INCH OF
                 SLEET AND ICE.
0.33   1 NE BATTLEFIELD         MO GREENE           0809 AM
                 SLEET FELL IN 90 MINUTES. ADDITIONALLY ONE
                 TENTH INCH OF FREEZING RAIN ACCUMULATION.
0.25   JOPLIN                   MO JASPER           0634 AM
                 MEASURED AT THE JOPLIN AIRPORT.
0.25   CLEVER                   MO CHRISTIAN        0800 AM
0.25   LAMPE                    MO STONE            1024 AM
                 ONE QUARTER INCH OF SLEET ON THE GROUND AND A
                 GLAZE OF ICE.
0.25   THAYER                   MO OREGON           0200 PM
                 REPORT RELAYED VIA LOCAL NEWSPAPER. QUARTER
                 INCH OF ICE. SOME WEAK SMALL TREE LIMBS DOWN.
0.25   WILLOW SPRINGS           MO HOWELL           0215 PM
                 ALSO AN INCH OF SLEET.
0.25   ALTON                    MO OREGON           0230 PM
                 SOME LIMBS DOWN ONTO POWERLINES CAUSING FIRES
                 IN THE COUNTY.
0.25   PINEVILLE                MO MCDONALD         0300 PM
                 MOST OF THE SLEET HAS MELTED.
0.25   MARSHFIELD               MO WEBSTER          0330 PM
0.20   PITTSBURG                MO HICKORY          0700 AM
0.10   FORT SCOTT               KS BOURBON          0624 AM
                 TENTH INCH OF SLEET ALONG WITH 1.25 INCHES OF
                 SNOW. PRECIPITATION BECOMING FREEZING RAIN
                 RESULTING IN AN ADDITIONAL GLAZE OF ICE.
0.10   SALEM                    MO DENT             1041 AM
                 FREEZING RAIN ACCUMULATION ON ROADS, POWER
                 LINES AND TREES. MIXING WITH SLEET NOW.