“Heavy rainfall is likely across portions of Nicaragua and Costa Rica today into Saturday. Areas of life-threatening flash flooding and mudslides are expected,” the National Hurricane Center wrote.
Bonnie is one of three tropical systems forecasters have been monitoring. One disturbance, which formed in the western Gulf of Mexico, has already moved over the upper Texas coast and southwest Louisiana. Although it did not organize sufficiently to become a named storm, it has unloaded torrential rain north of Houston.
A third disturbance, on the heels of Bonnie, is given a 10 percent chance to become a tropical depression or storm through the weekend. But it is expected to bring gusty showers Friday into Saturday in the Windward Islands, which bridge the Atlantic and Caribbean.
Bonnie, the second named storm of the Atlantic hurricane season, formed 16 days ahead of average. The National Oceanic and Atmospheric Administration projects a busier-than-normal season — with 14 to 21 named storms, including six to 10 hurricanes and three to six major (Category 3 or higher) hurricanes. The Atlantic season typically peaks in late August and September.
Details on Tropical Storm Bonnie
Bonnie is a minimal tropical storm, packing winds of 40 mph. The Hurricane Center forecasts modest strengthening before landfall, when peak winds could hit 50 mph.
While such winds will be rather gusty and could cause downed trees and power outages, the primary hazard is heavy rainfall as the storm transits Central America.
The Hurricane Center projects 4 to 8 inches of rain and localized amounts up to a foot in Nicaragua and Costa Rica.
Bonnie could also generate a minor ocean surge — or rise in water of 1 to 3 feet above normally dry land near and just north of where its center makes landfall.
After sweeping across Central America, Bonnie is expected to emerge in the Pacific Ocean, where it is predicted to gain strength and potentially become a hurricane early next week. However, it is not expected to threaten land.
According to tropical weather researcher Phil Klotzbach, Bonnie is somewhat of a rarity — among one of six named storms on record to form in the Caribbean during July.
Texas-Louisiana tropical rainstorm
Meanwhile, the disturbance that formed over the western gulf is bringing a flood threat from around Galveston, Tex., to Lake Charles, La., on Friday.
Flood watches cover this entire zone through the afternoon or evening. As of midday, the heaviest rain had moved north of Houston and Galveston but was drenching the Golden Triangle area, which includes Beaumont and Port Arthur, where flash flood warnings are in effect until 3:45 p.m.
“Between 4 and 8 inches of rain have fallen,” the National Weather Service wrote. “Additional rainfall amounts of 1 to 3 inches are possible in the warned area. Flash flooding is already occurring with several reports of street flooding received from Port Arthur and surrounding areas.”
The Weather Service issued a special bulletin warning that rainfall rates could exceed three inches per hour at times.
Radar showed torrential rain between Beaumont and Lake Charles at midday Friday, but forecast models project downpours to gradually subside by evening.
While as much as 8 inches had fallen in the Golden Triangle region, most areas of Houston had seen about one-tenth of an inch. The rainfall skirted much of interior Texas, which is enduring extreme drought and relentless heat.