Snow In Florida

The forecast for snow and sleet I posted in my blog a week ago verified and we had snow flurries as far north as Palm Coast and Crescent City in northern Florida.  It is extremely hard to predict a snow event for the sunshine state. It snowed in other parts of Florida. Flurries fell as far south as Kendall the same day Saturday January 9th 2010.  Several other locations around Miami and also Boca Raton had flurries.  No snow fell in Jacksonville due to dry air evaporating the flakes before they fell to the ground.  The air was more moist behind the Arctic front in Central and south Florida.  This provided an environment for sleet and flurries south of Jacksonville.

This Skew-T sounding from Jacksonville at 7 am shows the green dew point line matched with the red temperature line which stays below freezing. The extra space between green and red lines at the bottom shows the dry air layer near the ground over Jacksonville which caused the snow to dry up before reaching the ground. Closer vertical lines represent more moisture in that layer of the atmosphere.  Altitude increases from bottom to top and temperature decreases from right to left.

The snow set up was unique in that arctic air was parked over the state while moisture was drawn out of the Gulf from an upper level short wave in the jet stream.  This created a saturated moisture profile through the atmosphere.  Where freezing levels were low enough some flakes reached the ground.  Most areas had a warmer mid layer that caused the flakes to come down as sleet and ice pellets.  The second graph shows the freezing layer at 1104 feet with deeper moisture close to the ground at 7am in Tampa.  Sleet fell in Tampa.

It has been colder but is rare to have the cold last so long. Jacksonville had 6 nights of back to back freezes in a row but missed setting a record for consecutive freezes set in 1977 for 8 nights below freezing.  St. Simons island and Alma Georgia however broke a record for the longest run of frozen nights since 2000/01 winter.  Temperatures reached the teens Monday morning 1-11-2010.

The extended cold caused the Intercoastal Waterway in Ponte Vedra to freeze near the edge.  This is brackish water and the salinity must of been low enough to alow ice to accumulate.  Dead fish were near as a result of the cold water. I saw widespread fish kills around Tampa Bay and along the beaches in Treasure Island the following weekend. Fernandina Beach water temperatures are 45 and the Atlantic is 52 but shallow protected parts of the ICW may of dropped to 32 degrees.