IEM Daily Feature
Tuesday, 29 August 2017

Max 24 Hour Precipitation

Posted: 29 Aug 2017 05:34 AM

The hard to fathom amounts of accumulated precipitation continued overnight for SE Texas from Tropical Storm Harvey. Many locations in the Houston area have reported 24 hour totals well above 10 and even 15 inches. Putting aside that some of these same locations have reported such amounts for multiple days in a row, has Iowa ever seen anything close to those amounts? The featured map presents 24 hour max accumulations for long term climate sites that the IEM tracks. Almost all locations on the map have seen maximum amounts well below even 10 inches. The 13.18 report was from Atlantic back in June 1998. How can such a large difference exist between here and Texas? Iowa does not see slow moving tropical systems with a direct and immediate fetch of extremely moist air from the Gulf of Mexico. Our heavy rain makers tend to be progressive (they move along), don't last long enough to pile up 10+ inches of rain (sources of rich moisture are transient), and not as efficient of rain producers as tropical storm systems (cloud ice and hail reduce rainfall rates).

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Tags:   climate