The issues associated with the dramatic increase in all severe weather reports over the last several years is one of the topics we hope to discuss and put into some perspective using this forum. Yesterday’s severe weather illustrates the huge leap in the number of reports coming in from storm spotters and the public. There were over 300 severe thunderstorm wind reports on Wednesday, February 11, 2009.
While yesterday’s data remain preliminary, here are the official top 10 wind report days occurring in either the month of January or February since 1955:
It’s no real surprise that all these days have occurred since the 90s. The NWS has undergone dramatic restructuring during this time and the emphasis on documenting severe storm events has likewise increased. That, in combination with an increase in population and a technological revolution in communications technology (cell phones, the web, etc.) have led to a rise in storm event reporting.
However, severe weather events during the winter months are not that common. Significant thunderstorm wind events during January and February are even less common (refer to the list). The first and only time until yesterday that more than 300 severe thunderstorm wind reports occurred on a single day in January or February was just last year on January 29. Wednesday’s event will be the second time we’ve equal or exceeded that number on a January or February day since 1955. Even more remarkable is that 4 out of the top 10 January or February thunderstorm wind days have all occurred in a little over the past year.
Some of this is obviously due to the factors discussed above. How much of it is due to a real trend in severe weather during the cold season remains an open question. Or, do these episodes occur every so often in the long-term record and we are only beginning to see them due to the increased density of the reporting network?