We looked at a NUCAPS example in West TX late this afternoon (data at 19z), near the area where terrain enhanced convection was firing. After modifying the sounding for representative surface temperature/dew point (KFST surface observation site), we compared the ML CAPE and mid-level environment to the latest SPC meso-analysis. The comparison was favorable (SPC CAPE 1000-1500, with the NUCAPS sounding around 1200). Dry well mixed mid-level environment also seems quite representative compared to observed mid-level lapse rates from the meso-analysis data and actual GOES-13 water vapor imagery.
Due to the presence of broken clouds, steep mid-level lapse rates, and fairly uniform surface conditions, the environment appears to be favorable to maximize the success of NUCAPS retrieval abilities.
This is an optimal example of when NUCAPS soundings could be used operationally with confidence, and thus will provide good material for training purposes. Please see attached.
Unfortuantely AWIPS II does not display NUCAPS MW-only derived retrieval but only the MW+IR derived one. MW-only retrievals are insensitive to non precipitating clouds and can offer an alternative solution when the NUCAPS MW+IR fails. It can also be used as diagnostics to flag the presence of a cloud. I regenerated these plots using data from DB.
ReplyDeleteNUCAPS closest retrieval shows the MW only being accepted at 27km away from the KFST station (lat = 30.93; lon = -102.95). The closest accepted MW+IR is about 70km away (what is shown in the pictures of the post). NUCAPS MW-only shows that almost no correction is needed towards the surface. This is a really interesting case where the MW-only from NUCAPS can still provide a good frame of reference for a pre-convective regime. (Figures cannot be displayed in a comment apparently).
AG
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