Odds continue to grow for a slow, sloppy storm bridge in the Gulf of Mexico to become a tropical system in the next few days.
During an 8-year counsel, forecasters showed the chance of formation from 50 percent to 60 over five days as the system moves north from Belize and the coast. Although there is no tropical depression or storm, parts of South Florida that are already at risk of breaking monthly rainbits can see more rain.
Upper levels of windshielding and proximity to the Belize coast are expected to keep the system more organized over the next two days. But as it moves north and approaches the central bay on Friday or Saturday, slow progress on hot water allows the system to evolve, "said AccuWeather Senior Meteorologist Dan Kottlowski. What is not clear is whether there is a sufficient gap in the shear and now helps prevent this formation, he said.
"The problem of shearing is shear can weaken for a short period of time," he said.
Where the worst rain from the storm also falls uncertainly. Forecasters expect South Florida to see a lot of rain, but models are increasingly consistent with the dense plum of moisture remaining offshore, says Kottlowski.
Immaculate rain during the past month has pounded much of the region. Nearly eight inches have fallen along the coast of Miami-Dade County, according to the South Florida Water Management District. Broward County's coast has received 12.24 inches, more than three times the normal amount of the month. Between Monday and Tuesday, Big Pine Key got 4.17 inches.
The wet weather derives from a late season cold blast in the north, Kottlowsk said. After cooling in the north east, the cold air in the upper atmosphere determined the southern Gulf of Mexico, which weakened the circulation below.
"When you create a pattern, you dampen deep tropical moisture from the equator," he said. "It's not really normal, but it's not uncommon."
The lack of organization also makes it difficult to forecast and determine the location of the heaviest rain.
"It does not mean it will not rain," he said, "it just means that the heaviest activity could stay off the west coast of Florida."
There is also another wrinkle: there is a chance that the system may become a subtropical system that resembles a tropical system without the hot center. Such storms can generate the same amount of wind and rain, says Kottlowski but tend to have elongate shapes and produce stronger winds along its outer perimeter.
If it becomes a tropical system – the first name will be the storm to be Alberto – it may appear a few days before the official season's start next Friday. The system is also the first investment in the season. Last year, the Center for Energy for the first time began to forecast forecasts for investments close to the ground to give the public and emergency managers more time to prepare. The designation does not mean that a system is more likely to form.
As the flooding is the main cause of death linked to tropical systems, forecasters have also made greater efforts on rain warnings this year. Hurricane Harvey led to over 80 deaths in Texas last year after receiving outstanding rain, with a new US record set of more than 60 inches.
This year, the National Prediction Center plans to issue more specific rainfall maps predicting risk levels, although forecasters still can not combine flood risks from both rain and storm waves.
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