May 20, 2013 - Marlow, Oklahoma EF1 Tornado
Two tornadoes occur near Duncan, Bray and Marlow, Oklahoma causing minimal damage, while a violent EF5 tornado strikes the city of Moore causing mass destruction. We ended our chase in north Texas near St Jo.
Tornadoes occur near Marlow, Oklahoma
After successful consecutive tornado intercepts on the 18th and 19th in Kansas, today had another shot of tornadic supercells across central Oklahoma. The atmospheric setup today consisted of a dry-line, strong 3,000-3,500 j/kg instability, 50-60 knot 0-6km shear and an upper level disturbance.
Our target area was about 70 miles south of Oklahoma City closer to the dry-line bulge. We drove west through Newcastle on I-44 to get in position. Oddly enough, we had no idea an EF5 tornado would plow through this area 3 hours later. Cumulus clouds were developing along the dry-line signaling storms were going to develop. The Storm Prediction Center had issued a tornado watch for all of central Oklahoma. We traveled south on highway 81 and intercepted two storms. The one to our west looked strong, but was moving back to our north away from our position. An additional cell to our south formed and showed some promise with its development.
The guys had disagreements amongst what storm to go after. Tensions rose a bit, but that's normal when decision making is involved when hoping to find the storm that might produce a tornado. My gut went with the south storm since it was coming towards us, better terrain and it had no other storms interfering with it. Soon, severe thunderstorm warnings were issued for both storms to our north and south of our location. Ultimately after bickering, the storm to our south had become tornado warned and this would be the one to chase. It was about 20 miles to our southwest.
CG Lightning Barrage
This supercell had an incredible amount of cloud to ground lightning strikes in its forward flank. The guys mentioned this phenomenon can occur prior to tornadogensis. We finally parked south of highway 29 west of Marlow/Bray, Oklahoma. The wall cloud was in the distance and did produce a funnel cloud for a few minutes near Duncan, Oklahoma. Cloud to ground lightning continued to increase as we sat at our location for at least 30 minutes. At this time, on the radio, an EF5 was unfortunately plowing through Moore, Oklahoma. Finally, a tornado was visible through the rain to our west near Marlow. The guys relayed the report to the NWS and it became wrapped in rain after 5 minutes.
Red River, Texas HP Supercell
This storm appeared to weaken somewhat, so we decided to drive south to chase a monster HP supercell along the Red River valley. The storm was something I was hesitant to mess with, but we went for it anyway. It was huge and had a strong velocity couplet wrapped in rain on radar. The road network was tricky as well due to the storm that was parallel to the river. Soon, we positioned ourselves on the south side of the storm and it had become more outflow dominate near St Jo, Texas. We called it a day, checked in a hotel and stopped at Chili's to get some grub. We found out how massive the tornado devastation was in Moore, Oklahoma. Initial reports had the death toll near 100 with many children being killed at Plaza Towers elementary school. We sat in our booth amongst other storm chasers with somewhat of a somber mood for very good reason.
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