The Dodge City, KS WFO launched a special 1900 UTC sounding, roughly the same time as a NUCAPS pass. Therefore, comparisons were made between the RAOB and a nearby NUCAPS. The NUCAPS profiles were not automatically modified, so user modification was needed. The surface temperature and dew point were both adjusted up roughly 5 degrees to match that of the radiosonde profile. The rest of the NUCAPS profile matched very well with the raob in terms of general shape. The 500 mb temperature in both profiles was -12C, while the 300 mb temperature was -43C in both. The NUCAPS profile captured drying between 700 mb and 500 mb, and moistening above. Upon modification of the NUCAPS surface conditions, the thermodynamic fields matched very well. ML CAPE was around 2000 j/kg in both, while SBCAPE was around 3060 in NUCAPS and 3200 in the raob. The LCL in the NUCAPS profile was around 5100 ft, while that in the raob was closer to 5500 ft.
On a similar note, a quick way to gauge the accuracy of the NUCAPS LCL in the absence of a radiosonde is to compare with cloud bases (if present) in surface observations. In this case, the DDC surface ob reported FEW at 5500 ft, matching that of the radiosonde.
Finally,
- Bucky
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