A strong storm system and associated cold front moved into the Southern Plains on the 10th. Unseasonably warm and moist air spread northward from the Gulf of Mexico ahead of this system, resulting in weak to moderate instability developing across eastern Oklahoma and northwest Arkansas. This instability, combined with very strong wind fields and wind shear, resulted in organized severe thunderstorms. The strongest storms produced large hail up to golfball size, damaging wind, a tornado, and flash flooding.

Hail in TULSA, OKLAHOMA
From 10-JAN-20 11:38:00 to 10-JAN-20 11:38:00 (CST-6)
Location: TULSA
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Tornado in CHEROKEE, OKLAHOMA
From 10-JAN-20 14:49:00 to 10-JAN-20 14:57:00 (CST-6)
Location: PETTIT
Tornado F-scale: EF1
Property damage: 50.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado damaged the roof of a permanent home and the roofs of two mobile homes, uprooted a number of trees, and damaged outbuildings. Based on this damage, maximum estimated wind in the tornado was 90 to 100 mph.

Flash Flood in PITTSBURG, OKLAHOMA
From 10-JAN-20 18:00:00 to 10-JAN-20 22:30:00 (CST-6)
Location: ASHLAND
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Portions of several roads were flooded across southwestern Pittsburg County, as a result of three to five inches of rain that fell across the area. A 58 year-old man drove his pickup truck into deep flood water flowing over S Harper Valley Road, where it became inoperable. He exited the vehicle, was swept downstream by the rapidly flowing water, and  was drowned.

Tornado in MAYES, OKLAHOMA
From 10-JAN-20 11:55:00 to 10-JAN-20 11:56:00 (CST-6)
Location: MURPHY
Tornado F-scale: EFU
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Storm chasers positioned in two different locations observed a brief tornado. The area where the tornado occurred was inaccessible by road, thus there was no known damage.

Hail in CHEROKEE, OKLAHOMA
From 10-JAN-20 15:02:00 to 10-JAN-20 15:02:00 (CST-6)
Location: TAHLEQUAH
Magnitude: 1.75 
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in SEQUOYAH, OKLAHOMA
From 10-JAN-20 16:09:00 to 10-JAN-20 16:09:00 (CST-6)
Location: SALLISAW
Magnitude: 61.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Strong thunderstorm wind blew down power poles and trees. A storm spotter estimated wind gusts up to 70 mph.

Flash Flood in PITTSBURG, OKLAHOMA
From 10-JAN-20 17:47:00 to 10-JAN-20 22:45:00 (CST-6)
Location: MC ALESTER
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: County Official

Multiple vehicles were driven into flood water, where they were stranded.

Flash Flood in LE FLORE, OKLAHOMA
From 10-JAN-20 20:11:00 to 11-JAN-20 00:30:00 (CST-6)
Location: POTEAU
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Portions of several roads were flooded in and around town.

Hail in TULSA, OKLAHOMA
From 10-JAN-20 11:35:00 to 10-JAN-20 11:35:00 (CST-6)
Location: TULSA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Hail in TULSA, OKLAHOMA
From 10-JAN-20 11:36:00 to 10-JAN-20 11:36:00 (CST-6)
Location: TULSA R L JONES ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager