New system is likely to bring heavy rain and gusty winds to Florida late in the week

A large zone of disturbed weather extends from the western Caribbean across Mexico’s Yucatán Peninsula into the extreme southern Gulf. Later today or tomorrow, this broad circulation will be boosted by upper-level spin and moisture leftover from former-Hurricane Agatha, which will likely dissipate today over the mountainous terrain of southern Mexico.

The question becomes, what type of system will consolidate from this giant circulating blob and head toward Florida?

An upper-level kink in the jet stream is forecast to dip south into the Gulf. This will have the dual effect of providing some energy to help a consolidated system form, and it will lift it, whatever it is, northeast toward Florida.

These upper-level winds are forecast to create a fairly hostile atmospheric environment over the Gulf, which will include a lot of dry air, so a strong system is not likely. A tropical storm – that is, a system with winds of 40 mph or higher – is certainly possible, however.

The only thing certain about this scenario is that a large amount of tropical moisture is going to get dragged toward Florida late in the week. The timing, the strength of the accompanying winds, and the part of the Florida peninsula to be affected are unknown, except that South Florida is likely to experience heavy rain in most imaginable scenarios.

Heavy rain has plagued the Miami/Fort Lauderdale area since the rainy season began a couple weeks ago, and more is forecast for today. The saturated ground raises the threat of significant flooding from more heavy rain.

The arrival time of the rain will depend on how quickly a system can form and how strong it gets. There is no consensus among the computer forecast models yet, which is often the case before a defined low-pressure system consolidates.

Floridians should be ready for a two-day period of rain beginning as early as Thursday or as late as Friday. Whether Central Florida gets in on the heavy rain is an open question. Unless the system stays very weak and misses the peninsula to the south, it’s hard to see how South Florida can avoid impacts.

The rule of tropical-system forecasts is: Forecasts for disorganized or just developing systems are always subject to large errors and likely to change. This applies double in this case. The “system” we are talking about hasn’t even begun to develop.

Stay tuned.