Tuesday, May 12, 2015

Severe hail in NC

A storm in North Carolina took a while to get its act together, but then took off in a hurry! Going from 20% to 53% to 89% ProbSevere values. Strong satellite growth brought the probability to 20%, while the MESH was still very low (0.38"). However, this was certainly the highest probability of any shower/storm up to that point. A forecaster in Sterling, VA noted that she liked the trend upwards in ProbSevere. An official NWS warning was issued at 20:54Z, and 1" hail was recorded at 21:12Z (this was outside our forecasters' CWA). This is a case where the forecaster should be aware that there are no 'magical' thresholds in probability, but the strong satellite trends could still highlight severe potential (a 1 in 5 chance in this case, at 20:48) despite weak MESH.

ProbSevere, GOES-East IR window BT, and composite reflectivity (20:48 UTC)

ProbSevere, GOES-East IR window BT, and composite reflectivity (20:50 UTC)

ProbSevere, GOES-East IR window BT, and composite reflectivity (20:52 UTC)

-Cintineo

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