Thursday, February 4, 2016

A Wet Winter in the Sunshine State

Northern snowbirds heading to Florida this winter have not experienced the normal "dry season" that typically occurs during the winter. The development of El NiƱo this year has modified the overall storm track across the southern U.S., and the southeastern U.S., particularly southern Florida, has experienced a wet winter.

November was very wet across the Carolinas and Georgia. Precipitation across Florida was normal to lightly above in Florida except for the far south, where precipitation was 1.5 times normal. In December the Carolinas, Georgia, and Alabama were wet with precipitation two to three time normal. However, there was an amazing precipitation gradient across Florida. The western panhandle experienced much above normal rainfall, but across the remainder or northern and central Florida precipitation dropped to as low as 25 percent of normal. Rainfall then increased markedly from central Florida to to 500 percent of normal or more across the southern tip of the state.

Monthly totals across southern Florida reported by CoCoRaHS observers ranged from 10 to more than 19 inches of rain. The bulk of the December rain fell during the first week of the month from December 4-6. A stationary front extending from the western end of Cuba across the Florida Keys and strong onshore flow  produced by strong high pressure to the north provided the fuel and the mechanism to produce torrential rain especially over Miami-Dade County.

Daily rainfall in December 2015 for CoCoRaHS station Fl-MD-22 Hammocks 0.5 SSE

January brought more of the same, but the joy was spread much farther northward. Central Florida, which was very dry during December, received from 125 to 200 percent of normal rainfall. During January the largest departures from normal occurred on the southwest coast of Florida.

Many locations reported in excess of 10 inches of rainfall, and the heaviest rain occurred in Lee County, where five CoCoRaHS observers tallied more than 16 inches of rain during the month. Unlike December the rainfall in January was somewhat more distributed during the month depending on location.

Daily rainfall in January 2016 for CoCoRaHS station FL-LE-5, Lehigh Acres 4.2 WSW.

A number of locations in southern Florida recorded their wettest January on record, breaking old records by 1.5 inches or more.

Graphic credit: NWS Miami, FL

As you might expect, the excessive rainfall caused many flooding problems. Emergency pumping has been initiated in communities near Okeechobee, and the U.S. Army Corps of Engineers has begun to lower the lake by discharging into the Atlantic and the Gulf of Mexico to lessen stress on the lake's dikes. Unfortunately the discharge also contaminates the estuaries along the coasts.

Flooded field in Florida.
Photo credit: Florida Dept of Agriculture
Agriculture is also taking a hit from the heavy rain. Flooded fields and saturated soils have disrupted harvesting activities and the wet conditions promote vegetable disease conditions. Some crops have also been damaged by some of the high winds that have accompanied the storms.

Despite all of the rain in northwestern Florida and the southern half of the state, December-January rainfall remained below normal in the northeastern portion of the state.

After a dry day Tuesday, heavy rain was sweeping across northern Florida today as storms developed ahead of the cold front moving through the state.

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