March is typically considered a violent month of temperature, precipitation, and storm extremes. The same holds true over the Ocean Prediction Center’s offshore zones that extend from 60 nm to 250 nm from the east and west coasts. These storms also occur over the Tropical Analysis and Forecast Branch’s offshore zones shown in the yellow boxes south of 31N. These Atlantic offshore zones have experienced a particularly active period of strong supercell thunderstorm activity due to the active quasi-zonal flow racing across the eastern U.S.
The first event occurred between 0500-1500 UTC on 03/15/16 and consisted of multiple convective clusters which included one left-moving supercell east of NC, some right movers south of 31N in the TAFB’s offshore zones, and a particularly explosive clusters of storms east of SC that exhibited some supercell characteristics. These storms were initiated by a potent shortwave that produced severe weather over AR, LA, and TN on 03/13/16, then more potent storms over VA and NC on 03/14/16.
The second event occurred between 0200-1300 UTC on 03/17/16 and consisted of one, renegade, cyclical supercell. The storm formed around Salisbury, MD around 0200 UTC, pushed off of the Ocean City, MD coast around 0400 UTC, and seemed to pulse until it finally crossed the north wall of the Gulf Stream. From that point, the lightning activity increased to a point that is beyond the thresholds set in the lightning density product. The strong right movement tangential to the westerly flow leads me to suspect this storm was rotating rather violently and may have been producing strong waterspouts and dangerous winds for mariners.
These are two examples of how important it is for the Satellite Proving Ground to work with forecasters at OPC and TAFB to identify these potentially dangerous cases. Numerous ships traverse these offshore waters daily and these events are very challenging to predict, never-mind monitor without the use of radar. The lightning density product coupled with the imagery and overshooting top magnitude product (not shown this time) are envisioned to help forecasters and mariners identify the most dangerous storms to avoid if possible.
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