Spot Forecast
Issued by NWS Jacksonville, FL
Issued by NWS Jacksonville, FL
515 FNUS72 KJAX 171956 FWSJAX Spot Forecast for Paynes Prairie Rx...Paynes Prairie Preserver State Park National Weather Service Jacksonville FL 356 PM EDT Mon Aug 17 2026 Forecast is based on ignition time of 0900 EDT on August 18. If conditions become unrepresentative, contact the National Weather Service. Please contact our office at (904) 741-4370 if you have questions or concerns with this forecast. ...EXTREME HEAT WARNING IN EFFECT FOR TUESDAY 11AM TO 8PM... .DISCUSSION... Tuesday, very hot and humid conditions are expected as high pressure ridging remains over the eastern Gulf waters with westerly winds of 10 to 15 mph and highs reaching the middle 90s. A cold front will approach from the northwest and allow for scattered to numerous thunderstorms to develop in the afternoon hours. An early start to the Gulf seabreeze will create isolated showers and thunderstorms over the site during the late morning to midday hours. Peak heat index values 110 to 114 degrees. Isolated strong to marginally severe thunderstorms are possible in the afternoon hours. Storms will end after sunset. Tuesday night, mostly cloudy skies will remain with a few showers possible overnight. Lows will be in the upper 70s with west to southwest winds 4-8 mph. Wednesday, the cold front will sink closer to the Florida and Georgia state line with mid to late morning isolated showers and thunderstorms becoming numerous in the afternoon. Westerly winds 8-12 mph expected. Another hot and humid afternoon is expected with peak heat index values of around 110 degrees. Dispersions will be in the good range due to elevated mixing heights and light surface and transport winds. Gusty and erratic winds are possible within stronger thunderstorms Tuesday and Wednesday. .TUESDAY... TIME (EDT) 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM Sky (%).........42 52 54 55 62 68 73 72 69 Weather cov..... CHC CHC CHC CHC CHC CHC CHC Weather type.... RW RW RW RW RW RW RW Tstm cov........ CHC CHC CHC CHC CHC CHC CHC Chc of pcpn (%).10 10 30 30 40 50 40 40 30 Chc of thdr (%).10 10 30 30 40 50 40 40 30 Temp............85 90 92 93 94 94 94 94 92 RH..............80 70 66 64 62 60 60 60 64 Heat index (F)..97 106 109 110 112 110 110 110 107 Wind chill (F)..97 106 109 110 112 110 110 110 107 20 FT wind dir..W W W W W W W W SW 20 FT wind spd..8 10 12 10 10 10 12 13 13 20 FT wind gust.13 16 17 16 16 16 17 20 20 Mix hgt (kft)...1.5 2.2 2.9 3.0 3.0 3.1 2.8 2.4 2.1 Transp wind dir.W W W W W W W W W Transp wind spd.12 12 13 12 10 10 12 13 14 Dispersion idx..22 33 40 39 36 35 35 36 35 LVORI...........3 3 2 1 1 1 1 1 1 .TUESDAY NIGHT... TIME (EDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM Sky (%).........74 73 79 83 79 79 73 69 67 72 68 58 Weather cov.....CHC SCH SCH SCH Weather type....RW RW RW RW Tstm cov........CHC SCH SCH Chc of pcpn (%).30 20 10 10 20 10 0 0 10 20 0 0 Chc of thdr (%).30 20 10 10 20 10 0 0 10 10 0 0 Temp............90 89 87 84 83 82 81 80 80 79 79 78 RH..............68 68 72 80 82 85 88 91 91 91 91 97 Heat index (F)..105 102 99 94 92 90 88 87 87 79 79 78 Wind chill (F)..105 102 99 94 92 90 88 87 87 79 79 78 20 FT wind dir..W W W W SW SW SW SW W W W W 20 FT wind spd..13 12 10 8 7 6 6 5 5 5 5 5 20 FT wind gust.20 17 16 13 10 9 9 7 7 7 7 7 Mix hgt (kft)...1.7 1.2 0.8 0.7 0.6 0.5 0.5 0.5 0.4 0.4 0.4 0.4 Transp wind dir.W W W W W W W W W W W W Transp wind spd.13 12 10 9 9 8 8 8 8 8 9 9 Dispersion idx..28 19 9 8 6 5 5 5 5 6 6 6 LVORI...........3 3 3 4 4 5 5 6 6 6 6 6 .WEDNESDAY... TIME (EDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM Sky (%).........53 51 51 43 43 43 43 43 76 76 76 76 Weather cov..... SCH SCH SCH SCH SCH SCH LKY LKY LKY LKY Weather type.... RW RW RW RW RW RW RW RW RW RW Tstm cov........ SCH SCH SCH SCH SCH SCH LKY LKY LKY LKY Chc of pcpn (%).0 10 20 20 20 20 20 20 60 60 60 60 Chc of thdr (%).0 10 20 20 20 20 20 20 60 60 60 60 Temp............78 78 79 83 87 90 92 94 94 95 95 94 RH..............94 97 94 85 77 70 66 60 58 56 55 56 Heat index (F)..78 78 79 93 101 106 109 110 109 110 109 107 Wind chill (F)..78 78 79 93 101 106 109 110 109 110 109 107 20 FT wind dir..W W W W W W W W W W W SW 20 FT wind spd..5 5 5 6 7 8 8 9 9 9 10 10 20 FT wind gust.7 7 7 9 10 13 13 14 14 14 16 16 Mix hgt (kft)...0.6 0.8 0.9 1.4 2.0 2.5 3.0 3.5 4.0 3.8 3.6 3.4 Transp wind dir.W W W W W W W W W W W W Transp wind spd.8 8 8 9 9 10 10 9 9 10 12 13 Dispersion idx..6 5 10 17 24 32 38 39 44 47 50 41 LVORI...........6 7 6 4 3 3 3 1 1 1 1 1 $$ Forecaster...Bricker Requested by...Brian Law Type of request...PRESCRIBED .TAG 2619864.0/JAX .DELDT 08/17/26 .FormatterVersion 2.0.0 .EMAIL brian.law@floridadep.gov