JACKSONVILLE, Fla. – Thunderstorms are expected to fire up well inland Sunday afternoon before spreading east and northeast throughout the day. The west coast sea breeze will be the main driver of storm development, with the merging of the west coast and east coast sea breezes expected to fuel the most active weather over northeast Florida after about 2 to 3 p.m.
The storms themselves won’t be fast-movers. Storm motion is forecast at only 6 to 10 knots, meaning slow-moving storms could drop 2 to 3 inches of rain quickly in some spots.
The biggest threats with any storms will be strong winds and dangerous lightning.
Scattered storm chances are expected to fade by evening, though some weaker storms may push toward the I-75 corridor well after midnight.
Dangerous heat prompts Heat Advisory
High temperatures Sunday are expected to climb into the mid to upper 90s across inland areas — and even the low to mid 90s at the beaches, where a delayed east coast sea breeze will offer less relief than it has in recent days. Those temperatures, combined with elevated dew points, will send heat index values soaring into the 105 to 110 degree range.
A Heat Advisory has been issued for eastern zones starting at 11 a.m. Sunday for areas east of U.S. Highway 301 and toward the coast.
Even with the storm threat potentially knocking back the most extreme heat indices during peak afternoon hours, conditions will remain dangerously hot and humid. Overnight lows will offer only modest relief, staying in the 70s for inland areas and hovering near 80 degrees along the coast.
Heat lingers into early next week
The dangerous heat is not a one-day event. Heading into the end of the weekend and through early next week, inland areas can expect high temperatures to remain in the mid to upper 90s. Coastal communities will see highs in the upper 80s to lower 90s.
Overnight lows will drop to the mid 70s inland and stay in the upper 70s along the shoreline and near the St. Johns River.
Heat index values are expected to top 100 degrees again on both Monday and Tuesday, with Heat Advisory conditions possible on both days.
Limit outdoor activities during the hottest parts of the day, stay hydrated, and check on neighbors, children and pets.