The base of an upper level trough was across the SE region. Light steering flow enabled both sea breezes to develop and move inland over a diurnally unstable airmass.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS JAX wrote it up.
The base of an upper level trough was across the SE region. Light steering flow enabled both sea breezes to develop and move inland over a diurnally unstable airmass. Upper level cool temperatures and dynamical lift enabled a few strong to severe storms along boundary collisions.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Jacksonville, FL wrote its last area forecast discussion before the first event at Jun 18, 2:08 PM EST, 4 hours 40 minutes earlier.
Area Forecast Discussion National Weather Service Jacksonville FL 308 PM EDT Thu Jun 18 2020 .NEAR TERM [Tonight through Friday]...Light sw flow is allowing seabreezes to move inland this afternoon. Relatively dry air still resides over the area with PWAT values in 1-1.4 inch range. Expect only isolated showers and storms until early evening and mainly over eastern zones where moisture/instability is slightly higher. Expect more coverage of showers and storms on Friday especially over southern zones due to the approach of an upper trough and and increase in moisture from the south. .SHORT TERM [Friday night Through Sunday night]...Upper trough will move off the east coast early Saturday morning with shorwave ridge moving into the area this weekend. Drier air with subsidence behind trough axis will result in low rain chances and mostly hot dry conditions. Only isolated convection expected with inland moving seabreezes during the afternoon hours. With light winds, afternoon temperatures will reach the lower 90s with heat indices near 100 degrees. .LONG TERM [Monday Through Thursday]...Ridge will be suppressed to the south next week as an upper trough develops over the eastern U.S. Impulses in a westerly flow aloft will aid convection and bring an increase in pops by midweek as moisture increases across the area. && .MARINE... High pressure ridge over the area will gradually shift south of the waters this weekend into early next week. Light south southeast winds will increase from the south southwest early next week. Seas will be in 2 to 4 foot range. && .PRELIMINARY POINT TEMPS/POPS... AMG 67 89 69 90 70 / 10 30 10 20 0 SSI 72 84 73 86 74 / 10 10 10 20 0 JAX 70 89 70 91 72 / 0 40 10 20 0 SGJ 70 85 71 88 72 / 0 20 10 10 0 GNV 68 89 70 92 70 / 10 30 10 20 0 OCF 69 89 70 91 70 / 20 40 20 30 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. &&
The Jacksonville radar (KJAX), 153 km away, was scanning. The volume nearest the first event began at 23:48 UTC.
3 thunderstorm wind, 2 hail. Local standard time, as filed.
A large tree was blown down near the intersection of County Road 314A and SE 65th Lane. The time of damage was based on radar.
Multiple trees were blown down along State Road 19 near Caravelle Ranch Wildlife Management Area. One fallen tree blocked the road.
Ping pong ball size hail was observed near Silver Lake. The time of the event was based on radar.
Golf ball size hail was reported near Peniel Road close to Silver Lake.
Several trees were blown down along Motes Road. Some trees had to be cleared off of the road by the fire department.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Florida in 2020Every state in 2020This day in weather historyWarnings in Florida, June 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 894322, 894324, 894323, 894325, 894326.