NWS/JAX

Weather Underground

...HEAT INDICES 104 TO 109 DEGREES THIS AFTERNOON...

...SCATTERED THUNDERSTORMS IN THE AFTERNOON AND EVENING...

Plan your trip Local Radar Detailed Forecast

Today: Partly cloudy with a chance of showers and thunderstorms mainly in the afternoon. Highs in the mid 90s. North winds 5 to 10 mph. Chance of rain 50 %. Heat index readings 100 to 104.

Tonight: Partly cloudy. A chance of showers and thunderstorms in the evening then a slight chance of showers and thunderstorms after midnight. Lows in the mid 70s. East winds 5 mph in the evening becoming light. Chance of rain 30 %.

Highs in the mid to upper 90s this afternoon will push heat index into dangerous levels of around 104 to 109 degrees. Use extra caution while outside today.

There is a better chance of scattered thunderstorms in the afternoon and evening with most of the activity across the inland areas. The main concerns with isolated stronger storms will be excessive lightning and strong down burst winds along with very heavy rainfall.

Forecast Details: surface data shows a weak low pressure system over southeast Georgiawith a broad trough of low pressure over central Georgia and South Carolina. Weak frontal boundary was located over South Carolina and extends east-southeast into the western Atlantic. Scattered convection finally weakened over the central portions of the County Warning Area as atmosphere slowly became more stable. Earlier laps analysis Wednesday showed cape values of 2500-3000 j/kg for areas just west of a Gainesville to Jacksonville line. Latest laps shows values highest over the marine zones near 2400 j/kg. Temperatures are in the middle and upper 70s at this time. Middle levels show high pressure system centered over the northeast Gulf of Mexico with the upper levels showing a TUTT low near 28n88w with 250 mb winds over the County Warning Area from southeast.

Today low pressure trough will remain near our northern zones today and initially westerly boundary winds will give West Coast sea breeze better inland progression. Still, winds are light enough for another East Coast sea breeze to generate a convergent area over inland northeast Florida and southeast Georgia. Models are in better agreement of scattered convection today with best chances from Ocala National Forest to Macclenny to Nahunta. Will keep probability of precipitation capped at 50% for now as GFS looks a bit too high. Steering winds expected to shift from north-northeast to northeast. Maximum temperatures today once again may be close to record territory at Gainesville, but heat index values are just short of heat advisory criteria (110 deg). Tonight isolated to scattered showers and storms expected with convection slowly winding down after midnight. Lows in the middle and upper 70s again.

Today's Pollen Levels: 4.5 Low Medium (on s a scale to 12); Predominate Pollen: Grass.

For additional information visit the National Weather Service in Jacksonville website on the internet at http://www.srh.noaa.gov/jax/