Update 7:40 p.m. The severe thunderstorm warning for southeastern Palm Beach County has been cancelled by the National Weather Service.
Forecasters in Miami say the worst of today’s storms have moved offshore, but a severe thunderstorm watch remains in effect until 10 p.m.
Update 7 p.m.: A severe thunderstorm warning for southeastern Palm Beach County is in effect until 7:45 p.m. Golf ball-size hail and 60 mph wind gusts could accompany this storm.
Update 6:12 p.m.: Hail has been reported from Jupiter to Lake Worth as the storms continue to simmer along the Palm Beach County coast.
An areal flood advisory has been issued for southeastern Palm Beach County with torrential rains hitting Boca Raton, Boynton Beach and Delray Beach.
Update 5:55 p.m.: A severe thunderstorm warning for southeastern Palm Beach County has been issued and is in effect through 7 p.m.
Update 5:49 p.m.: A significant weather advisory has been issued for south central Palm Beach County until 6:45 p.m.
NWS forecasters are watching a strong thunderstorm 19 miles southeast of South Bay moving southeast at 20 mph.
Up to nickel-size hail is expected with this storm and has already been spotted in Jupiter.
Update 4:50 p.m.: A significant weather advisory has been issued for northeastern Palm Beach County as a strong thunderstorm is being tracked over Jupiter Island moving southeast at 15 mph.
Update 4:37 p.m. The National Weather Service has issued a significant weather advisory for nickel-size hail in northeastern Palm Beach County.
Forecasters are watching a line of strong thunderstorms near the Port of Palm Beach moving east at 10 mph. They are expecting hail, torrential rainfall and possibly funnel clouds.
Areas impacted include West Palm Beach, Wellington, Palm Beach Gardens, Lake Worth, Riviera Beach, Greenacres and North Palm Beach.
Update 3:15 p.m.: A severe thunderstorm watch has been issued for Palm Beach County until 10 p.m.
The watch includes seven counties.
While the radar appears mostly free of storms over Palm Beach County currently, forecasters at the Storm Prediction Center said scattered large hail up to 2 inches in diameter could fall as thunderstorms pop up through this evening.
A thunderstorm watch means conditions are favorable for severe thunderstorms and people should be on the lookout for worsening weather conditions.
Update 3 p.m.: Storm Prediction Center forecasters issued their first localized discussion of today’s storms, saying “there is growing concern that initial severe thunderstorm development could be underway” before 4 p.m.
Palm Beach County is included in a an area where there is the greatest concern for large hail.
But forecasters noted that the coverage of the storms is unclear. Unlike a cold front, that marches through the state in a line, today’s storms are expected to pop up from daytime high temperatures interacting with extremely cold mid-level air. At the same time, a frontal boundary is stalled along Central Florida, which could add to the unsettled atmosphere.
Update 12:43 p.m. The Storm Prediction Center has upgraded Palm Beach County’s risk for severe weather this afternoon.
The risk level of “slight” is one rung higher than the previous ranking of marginal, and was increased as warm daytime temperatures ramp up to clash with extremely cold temperatures in the upper atmosphere.
The storm risk escalates after 2 p.m. with thunderstorms expected to last through early evening. Lightning, hail, up to 60 mph winds are the biggest concerns. There is also a slight chance of tornadoes.
Robert Garcia, a meteorologist with the National Weather Service in Miami, said measurements from this morning’s weather balloon triggered the increase in risk category.
Local weather forecasting offices send up weather balloons three times per day to measure data such as temperature in the mid and upper atmosphere and water content in the air.
“The thing that is really standing out to us today is the possibility for large hail and strong downburst winds,” Garcia said.
Thunderstorms with whipping wind gusts of 40 mph and the possibility of hail are expected to break out across South Florida today.
Meteorologists at the Storm Prediction Center, which had downgraded storm threats yesterday for the area, have again put Palm Beach County at a marginal level for severe weather.
About 84,000 people in central and southeastern Florida are in the marginal risk level, which is the lowest on a five-tier threat scale.
Miami forecasters with the National Weather Service are also predicting afternoon thunderstorms as the heat-induced sea breeze confronts a boundary that stalled over Central Florida last night.
Hail was reported last night by NWS trained weather spotters in Polk and Indian River counties as strong, but limited, thunderstorms bubbled up in the early evening.
“Yesterday, Central Florida experienced severe thunderstorms that produced hail reported to be the size of golf balls (or 1.75 inches in diameter) and today’s conditions over a good portion of the state will still be able to support such large hail if this afternoon and evening’s storms become strong enough,” said NWS meteorologist Robert Garcia.
Frigid temperatures in the upper atmosphere of just 10 degrees combined with today’s 80-degree high will help storms form as energy is created by the differences in temperatures with the rising warm air.
“Today’s environment seems supportive of at least some hail in the strongest updrafts over South Florida,” Miami forecasters wrote. “The best chance for robust convection is over Palm Beach County.”