On the last two days of April 2014 and extending to the first day of May, a powerful spring cold front initiated a deluge over the western end of the Florida Panhandle. The city of Pensacola seemed to be at the targeted center of this event. Over the course of three days, the maximum rainfall received near the city was over 600 millimeters, or about 24 inches of rain. The entire region received between 10 and 20 inches of rain.
Merged infrared (IR) data show the extremely cold tops of the convective storm clouds that were generated by the cold front, as it besieged the Gulf of Mexico coast on April 30. The color scale is in degrees Celsius. In general, colder cloud top temperatures indicate that the cloud tops are higher in the atmosphere and the storm beneath them is stronger. (Click on the image to see it full-size.)
The image below is a map of total rainfall (mm) from the NASA near-real-time TRMM Multi-satellite Precipitation Analysis (TMPA-RT) for the period of April 29-May 1, 2014. The area with the highest amount of rain (pink) was located between Mobile Bay and Pensacola Bay. (Click on the image to see it full-size.)
“The National Weather Service called the event “historic.” The official rain gauge at Pensacola’s air-port measured an astonishing 5.68 inches in a single hour before it failed around 10 p.m. Tuesday [April 29]. An analysis by the NWS office in Mobile, Alabama, estimated that single hour to be a 1-in-200- to 1-in-500-year event.”
As would be expected from an event of this magnitude, flooding was widespread and damage was extensive. The consequence of heavy rainfall in this area is compounded by geography, as there is very little slope in the flat coastal area to allow flood waters to flow off the land into the Gulf of Mexico. (Pictures of the flood damage at Storify.)
The Slate article also noted that the amount of rainfall is more than what this area has received from any recorded hurricane or tropical storm system. In fact, the normal amount of rainfall for the month of April in recent years has been about 100 mm, based on a climatological map of TRMM data created with the Giovanni-4 data analysis system (below). This map combines data from just the month of April over the past years, to depict the average rainfall for the month of April. (Click on the map to view it full-size.)
TRMM data are currently available from the Goddard Earth Sciences Data and Information Services Center (GES DISC), via its Mirador data archive and distribution system. TRMM data products can be analyzed with Giovanni. In the near future, the GES DISC will initiate the distribution of data products from the recently launched Global Precipitation Measurement (GPM) mission.