Event Analysis for February 15-16 Severe Weather Event

It seems like the narrative of the last year or so has been when there is a substantial event forecast, it mostly busts, while when little activity is expected, an outbreak occurs. This continued on February 15 and the morning of the 16th, when likely between 15-20 tornadoes touched down across Louisiana, Mississippi, Alabama, Florida and North Carolina. The SPC had highlighted the central Gulf Coast and the outer banks of North Carolina for potential severe weather the day before in Slight and Marginal risk areas. A 5% tornado contour was present from New Orleans, LA to Hattiesburg, MS to Pensacola, FL. While the general area was correct, what was forecasted to amount to a few tornadoes turned into the most substantial event of the year to date. Why did this happen?

Above is the special 18z (12 pm) sounding from New Orleans, LA. CAPE is in the 1300-2000 range, which is rather impressive for this time of year. While the wind profiles are not ideal for tornadoes, they are sufficient; Storm Relative Helicity values and lapse rates are definitely enough for organized storms and tornadoes. Significant tornado parameters are between 1-2, showing potential for a couple strong tornadoes. A key point was made by storm chaser Brett Adair (who lives in Alabama and is quite knowledgeable in these kinds of events) who said that while some parameters were not ideal, low-level instability combined with very cold air at mid-levels (otherwise known as lapse rates) can overcome some of these deficiencies.

The day before the event, I predicted 3 tornadoes, and said it was possible to go above 5. I was quite wrong, along with most other predictions. While the potential was certainly there, I (and many others) did not think that the high-end potential would come to pass. With that said, there were some things I should have noted. Lapse rates, along with CAPE, were quite impressive, and storm relative helicity values were also fairly high. There was just enough shear to keep storms rotating and to produce tornadoes. It was a hard forecast, and a reminder to people that cold-season events such as these remain very difficult for meteorologists to nail down.

The best thing that happened was the fact that there were no fatalities and not many injuries attributed to the storms, even though some of the tornadoes were significant and in fairly heavily populated areas. That is the best thing that can happen.

 

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