GOES-16 Derived Motion Winds show the southwest to northeast oriented upper-level jet shifting east into west Texas, OK panhandle, and western Kansas. Diffluent flow is apparent in the winds over south-central Kansas into the Texas panhandle on the east side of the jet where convection is already ongoing and initiating. As the upper forcing shifts east, so will the convection. Given the high cloud cover, mid-level winds are not available over the region. Winds in the 850 mb to 950 mb layer are available over much of central Oklahoma, indicating 25-35 knot low level southerly flow advecting moisture into the region. Some of the lowest level winds, below 950 mb, are indicating more backing toward south-southeast, which would imply a favorable shear environment for supercell thunderstorms.
Given the cloud cover, the LAP fields have very limited data across much of OUN. However, the all-sky product does have many cloudy sky pixels, a benefit of this product over the operational LAP product. Within these pixels, CAPE ranges from 1500 to 2000 j/kg across the CWA a reduction of close to 1000 j/kg over the GFS first guess. SPC meso-analysis indicates MLCAPE between 2500 and 3000 j/kg, implying LAP CAPE is too low. Boundaries are not easily identified in the retrieval data given the cloud cover.
MetOp-A NUCAPS soundings were available over the region for the 1630 UTC pass. The surface was adjusted to match the conditions present in the NWS Norman special 18Z sounding (surface of 78F T and 68F Td). Comparing the two, the NUCAPS sounding captures the EML, though it is with much less detail. NUCAPS tries to represent the temperature inversion, but it is too coarse to be operationally useful. The drying aloft is also present, though too high, with moistening above. The general shape of NUCAPS is on par with the raob. As for the CAPE fields, NUCAPS is a little hot with MU and SB CAPE compared to the raob, while MLCAPE is slightly too low.
- Bucky
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