The MCS (discussed in the previous post) developed rapidly after about 0830 UTC during the morning of May 12th. Top image above shows regional radar reflectivity at 03 UTC, which indicates the storms had quickly become very intense. The 08 UTC surface plot (just above) indicates that deep, moist and apparently very unstable, low-level air was advancing to the northwest just behind a narrow dry sector that was also retreating to the northwest. A weak, middle-level short-wave trough was swinging around the southern periphery of the cutoff cyclone over west Kansas. So, several interesting features were in play, even though the event was developing during the early morning hours before sunrise.
------------------------------------------------------------------------------
The most interesting aspect of this event is that model forecasts did not accurately forecast the delopment of these storms. The NSSL 12-hour, 4-km WRF forecast valid at 1200 UTC on the 12th (immediately below) indicated a small, intense cluster of storms near Corpus Christi, Texas. The 12-hour operational NAM model (bottom image) forecast an arc of storms at 1200 UTC over Galveston, Texas, extending southward into the Gulf of Mexico. Thus, the human forecaster still faces, even in this age of markedly improved forecast models, at times surprising and perhaps totally unexpected significant weather developments.
No comments:
Post a Comment