Recent reports of flooding rains in Tennessee and the torrential downpours from Hurricane Ida, and its remnants, brings the topic of flash flooding to IQ Weather.
September is the midpoint of hurricane season in the northern hemisphere.
Of course, hurricanes and tropical storms are very heavy rain producers, and there is always a threat for flash flooding with them. That is because they form over warm ocean water and, as a result, contain massive amounts of water vapor that can turn back into rain. Plus, tropical storm systems move rather slowly, so it takes a while for them to move over any one area. The slow movement increases the potential for rainfall dramatically.
It’s not uncommon for a tropical storm or hurricane to produce 20 to 30 inches of rain over any one location. In 2001, Hurricane Allison produced up to 40 inches of rain!
Water is a non-compressible fluid. It can produce enormous pressure on anything in its path. For example, water...
During the summer months, storm patterns and tracks shift farther northward. By mid-summer, the threat for severe storms weakens and shifts to the central and northern plains states and the upper Midwest.
The impact of the longer duration of daylight is to warm the atmosphere enough to cause the jet stream pattern northward. As you may recall from our IQ Weather lessons, the jet stream is a main ingredient for strong storm formation.
When the jet stream drifts farther north and weakens during the summer months, severe weather becomes less frequent.
As the end of summer approaches, and the overall atmosphere begins to cool, the jet stream will typically begin to drift back southward slowly. That sets up a second min-severe weather season in the autumn.
Summertime is also the early part of the hurricane season! As of today, we have had 5 named storms so far. The peak of hurricane season is in September, and hurricane season does not end until the last day of November. As you...