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February 17, 2011 NWS WFO Tulsa. SCEC: Oklahoma State Record 24-hour Snowfall & Minimum Temperature. Potential Record 24-hour Snowfall February 8-9, 2011. NWS COOP: Spavinaw (SPVO2) Measured 27” snowfall Mayes County, Oklahoma Station # 34-8380 Lat/Lon: 36°23’22”N, 95°03’35”W
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February 17, 2011 NWS WFO Tulsa SCEC: Oklahoma State Record 24-hour Snowfall & Minimum Temperature
Potential Record 24-hour SnowfallFebruary 8-9, 2011 • NWS COOP: Spavinaw (SPVO2) • Measured 27” snowfall • Mayes County, Oklahoma • Station # 34-8380 • Lat/Lon: 36°23’22”N, 95°03’35”W • Elevation: 685’
Spavinaw, Oklahoma NWS Cooperative Program Site Details This site has been staffed by the City of Tulsa since 10/1/1977 The current Observer has been taking observations for 15 years His observing practices are in accordance with NWS directives
Spavinaw, Oklahoma NWS Cooperative Program Site Details Specifics for the Snowfall Event on 02/09/2011 • The observer used sound snowfall measuring practices • Snowboard in place • Open exposure • Taking measurements at as many representative locations as possible
Spavinaw, Oklahoma NWS Cooperative Program Site Details • Snow was measured in the parking lot and near the gauges • The observer accounted for snow already on the ground from the previous week’s snow • Some settling may have occurred as the greatest recorded snow depth on the ground was 23”
Documentation of NWS Cooperative Program Site, Spavinaw, OK PARKING LOT EAST EXPOSURE PARKING LOT NORTH EXPOSURE MEASUREMENT SITE NEAR GAUGES PARKING LOT WEST EXPOSURE PARKING LOT SOUTH EXPOSURE Photos: Mike Teague WFO Tulsa 2/14/2011
Meteorological Conditions • An upper-level storm system moving across Oklahoma and Arkansas, and cold arctic air spilling south into the area, resulted in a major winter storm across eastern Oklahoma and northwest Arkansas Feb. 8-9, 2011. • Strong frontogenetic forcing led to a narrow band of intense snowfall that remained nearly stationary for several hours near a Ponca City to Chelsea to Fayetteville line. • See http://www.srh.noaa.gov/tsa/?n=weather-event_2011feb9
Meteorological Conditions...cont. • Snowfall amounts within the heavy band ranged from 12 to 18 inches in the western part of the band to 18 to 25 inches in the eastern part of the band. • Reports during the event of 2”/hour – 3”/hour snowfall rates in heavy snow band • Snow to Water Ratio of about 25:1 at NWS Tulsa
Snowfall at Spavinaw • From KINX radar (at COOP site): • Snow began: ~05z 2/09/2011 (11pm CST 2/08/2011) • Snow ended: ~00z 2/10/2011 (6pm CST 2/09/2011) • Heavy Snow band • Began: ~615z 2/09/2011 (1215am CST 2/09/2011) • Ended: ~15z 2/09/2011 (9am CST 2/09/2011) • 9 straight hours of heavy snow!
Kansas Oklahoma Missouri Arkansas
Heavy Snow Reports Note: these reports were received throughout the event from a variety of sources and may not represent storm totals .PRELIMINARY SNOW ACCUMULATION SUMMARY FEB 9 2011......REPORTS SORTED BY AMOUNTS...IN OKLAHOMA...25.00 INCHES OF SNOW 4 MILES SOUTH OF JAY IN DELAWARE COUNTY 25.00 INCHES OF SNOW 8 MILES EAST OF KANSAS IN DELAWARE COUNTY 24.00 INCHES OF SNOW 1 MILES SOUTH OF JAY IN DELAWARE COUNTY 23.00 INCHES OF SNOW AT JAY IN DELAWARE COUNTY 23.00 INCHES OF SNOW AT SPAVINAW IN MAYES COUNTY 22.00 INCHES OF SNOW AT COLCORD IN DELAWARE COUNTY 21.00 INCHES OF SNOW 3 MILES EAST OF BIG CABIN IN CRAIG COUNTY 20.00 INCHES OF SNOW AT DELAWARE IN NOWATA COUNTY 19.00 INCHES OF SNOW 9 MILES NORTHEAST OF CLAREMORE IN ROGERS COUNTY 18.00 INCHES OF SNOW AT PAWHUSKA IN OSAGE COUNTY 18.00 INCHES OF SNOW 2 MILES SOUTHEAST OF PRYOR IN MAYES COUNTY 18.00 INCHES OF SNOW 6 MILES SOUTH OF JAY IN DELAWARE COUNTY 17.00 INCHES OF SNOW 2 MILES SOUTH OF PAWHUSKA IN OSAGE COUNTY 16.00 INCHES OF SNOW AT BURBANK IN OSAGE COUNTY 16.00 INCHES OF SNOW AT ADAIR IN MAYES COUNTY 16.00 INCHES OF SNOW AT OCHELATA IN WASHINGTON COUNTY 15.00 INCHES OF SNOW 5 MILES SOUTHEAST OF KANSAS IN ADAIR COUNTY 15.00 INCHES OF SNOW AT WESTVILLE IN ADAIR COUNTY
Potential Record Minimum Temp February 10, 2011 • OCS Mesonet site: Nowata -31°F (7:40am CST) • NWS COOP: Ralston -29°F • coop id: 34-7390 • MMTS-1 • Lat/lon/elev: 36°30’N, 96°44’W, 825’ • NWS ASOS: Bartlesville (BVO) -28°F • 7:19 AM CST (1319 UTC) • HO83R temperature sensor • Lat/lon/elev: 36°45’45”N, 96°00’39”W, 715’ • Instrument verified by NWS technician 2/10/2011
Meteorological Conditions • Strong arctic high centered over northeast OK • Deep snow field in place over northeast OK at time of coldest observations • Clear skies, light/calm wind • Several observing sites and platforms reported low temperatures below -20°F • Generally from Noble County to Delaware County and north
BVO ASOS Nowata mesonet Ralston COOP Temperatures at ~6am CST Feb. 10, 2011
BVO ASOS Nowata mesonet Ralston COOP Temperatures at ~7am CST Feb. 10, 2011
Observations BVO-28°F 7:19am CST / 13:19UTC 02/10/11 07:05:31 5-MIN KBVO 101305Z AUTO 00000KT 10SM CLR M32/M36 A3035 320 69 -57 02/10/11 07:10:31 5-MIN KBVO 101310Z AUTO 00000KT 1/2SM HZ CLR M32/M35 A3036 320 73 -5700 000/00 RMK AO2 $ 02/10/11 07:15:31 5-MIN KBVO 101315Z AUTO 00000KT 1/2SM HZ CLR M32/M35 A3036 310 77 -5700 000/00 RMK AO2 $ • 02/10/11 07:18:26 SPECI KBVO 101318Z AUTO 00000KT 2SM HZ CLR M33/M36 A3036 RMK AO2 $ 02/10/11 07:20:31 5-MIN KBVO 101320Z 00000KT 6SM HZ CLR M33/M36 A3036 320 77 -5800 000/00 RMK AO2 $ 02/10/11 07:25:31 5-MIN KBVO 101325Z 00000KT 10SM CLR M32/M36 A3035 320 73 -5700 000/00 RMK AO2 $ 02/10/11 07:30:31 5-MIN KBVO 101330Z 00000KT 10SM CLR M31/M35 A3036 310 69 -5600 000/00 RMK AO2 $ 02/10/11 07:35:31 5-MIN KBVO 101335Z 00000KT 10SM CLR M31/M34 A3036 310 77 -5600 000/00 RMK AO2 $ 02/10/11 11:53:26 METAR KBVO 101753Z 22007KT 10SM CLR M08/M16 A3035 RMK AO2 SLP289 T10781161 11078 21333 58007 (AKP) -33.3°C = -27.94°F