General Synoptic Setup
The large scale synoptic pattern featured a strong positive tilt trough centered across the western US. This set the stage for strong southwesterly flow in the mid and upper levels. At the surface, low pressure was deepening across far western Kansas and Colorado. A stationary boundary was located across Texas early in the period, and was lifted northward as a warm front through the day in response to the aforementioned deepening low pressure. To the south of this boundary, temperatures rose into the mid 70's by afternoon. Thunderstorms were expected to develop along and especially ahead of the encroaching cold front, amidst increasing large scale forcing and a moderately unstable environment, owing to a unseasonably moist airmass in place, with dew points rising into the mid 60's by afternoon.
By Early Afternoon...
By 18z, special soundings from NWS Springfield, MO and the NWS Norman, OK gave a slightly better insight into the atmosphere. The Norman, OK sounding showed an unstable environment, where only some mid level clouds had persisted through early afternoon. The Springfield, MO sounding however, shows a very stable environment. It appears as though the warm front has just passed through Springfiield from this sounding, but the true warm air had yet to reach the area. Both soundings exhibit impressive deep layer shear values, with 88kts on the Springfield sounding!! Although the Springfield sounding showed a lack of appreciable instability, continued clearing along and south the warm front would continue to aid in destabilization, especially in the mid levels in the afternoon hours. At 19z low and mid level clouds were still persisting across all of eastern Oklahoma, with the main breaks in the clouds now occurring across extreme northeast Oklahoma, and along I-44 through central Missouri. In addition, higher clouds were still evident across central Oklahoma.
The 18z run of the HRRR ( High Resolution Rapid Refresh) pegged a few thunderstorms to develop around 22z along the I44 corridor in far northeast Oklahoma into southwest and central Missouri. With recent satellite trends, showing maximized destabilization potential over that area, this made sense. By 22z severe thunderstorms were already ongoing across far southeast Kansas into central Missouri. In the presence of strong low level shear, these storms briefly exhibited increased low level rotation, but no tornadoes were reported. A quick look through mesoanalysis data, and radar information as the event unfolded, shows that although storms were semi organized they were likely not surface based. A stable low level atmosphere kept the storms from tapping into the available moisture at the surface. 0-3km CAPE values however were indicative of sufficient instability to support strong thunderstorms updrafts. In the presence of the strong shear, any storm that was able to realize this mid level instability and sustain itself for a period of time, was able to take on supercell characteristics, as seen across southwestern Missouri. One storm in particular near Brighton, MO was able to produce a brief EF-1 tornado that caused some minor farm damage. This storm exhibited very strong low level rotation, and appeared to become surface based for a short time, noted by the wind reports from the storm.
What Went Wrong...
In general, rather meager low level lapse rates, and a lack of surface instability, in the presence of excessive shear, likely prevented a larger scale and more significant event. Morning clouds, and slightly over-forecast moisture values offered less instability than was expected. Those storms that were able to sustain themselves were able to transfer strong mid level winds to the surface, and a few storms in Missouri exhibited strong low level rotation, in the presence of impressive low level shear, and one produced a tornado. Ultimately though, today was characterized by a mainly wind and hail event.The thunderstorms across MO prove that constant analysis of the atmosphere becomes vital, especially with nearby frontal boundaries, that play significant roles in the thermodynamic layout of the atmosphere.
Pertinent Images From Today
11/24/10 12z 500mb Analysis
11/24/10 12z Sfc Analysis
SPC Storm Reports 11/24/10
Norman, OK Special 18z Sounding
Springfield, MO Special 18z Sounding
18z Vis Sat Imagery
(Note the clearing along the I44 Corridor)
22z 0-3km CAPE
(note the MAX near the storms in MO)
18z HRRR 4hr Forecast.. Valid 22Z