The center of Tropical Storm Cristobal will make landfall on the Louisiana coast later today or tonight. The worst weather with the gustiest winds is displaced ahead and well to the east of the storm – about 100 miles. It is already affecting the Gulf Coast from Louisiana to Florida.
Cristobal is shaped like a comma, which is not what a tropical storm is supposed to look like. In reanalysis, long after the storm is over, it might be judged to technically be “subtropical” or non-tropical, but regardless, it is what it is.
The tail of the comma is the moisture tail that we have been discussing the last few days. The core of the moisture feed has largely moved north of South Florida, and some there are some slots of drier air in it, but for the next few days, the flow into what was Cristobal will generally continue to pull tropical moisture over the Florida peninsula. Having said that, if forecasting exactly were a storm is going to hit is tough, forecasting where the tail is going to line up is harder, so we have to be ready for periods of heavy rain into midweek.
Even with the heaviest rain displaced away from the center, the moderate tropical-storm-force winds will still push the Gulf water into low-lying coastal areas from Louisiana around to the Florida west coast. The eastern part of Louisiana and most of the Mississippi coast could see the water rise 3 to 5 feet higher than the normal tide and the time when the strongest winds are blowing on shore.
Once Cristobal is out of the picture by midweek, the weather pattern will shift. In South Florida, a push of drier air is forecast to move in about Thursday, which should noticeably lower the humidity.
Elsewhere in the Atlantic, there is a slight chance that a short-lived system might spin up near Bermuda mid to late week. It’s certainly no threat to Florida, and doesn’t appear that it would be significant at the current time.