NEW TROPICAL STORM CRISTOBAL LIKELY TO FORM IN THE GULF TODAY
The disturbance over the extreme southern Gulf of Mexico, that is related to former Pacific Tropical Storm Amanda, is expected to spin up into a new tropical storm called Cristobal later today. This storm isn’t forecast to move very much, and will likely stay near the Mexican coastline through midweek or longer.
For later this week, the forecast is challenging, but the consensus of the computer forecast models brings Cristobal, or possibly another system formed out of the mass of moisture Cristobal is embedded in, toward the northern Gulf Coast.
Cristobal should not have any effect on South Florida in the next few days. High pressure has pushed over the peninsula from the Atlantic keeping the bad weather to the west. But later in the week, we’ll likely notice some changes.
The storm will not be renamed Amanda because the circulation at the surface of the earth was disrupted by the mountains between the Pacific Ocean and the Gulf. Since a new surface circulation has now formed, the storm will get a new name.
A complicating factor with this storm is that the depression that will likely become Cristobal has been embedded in a much larger low-pressure system called a Central American Gyre – a gyre being a large rotating weather system. These gyres are not uncommon, especially in the spring and also in the last part of the summer and early fall. Sometimes a smaller tropical system can break off from the parent gyre, and become a stronger independent entity.
The Gyre and the soon-to-be Cristobal appear to be merging now, but it’s unclear if the circulation that will become Cristobal will survive or another one will form.
The atmospheric pattern over the southern Gulf is generally conducive for strengthening, but if Cristobal migrates back over Mexico and runs into mountains, it will likely dissipate. Alternatively, if it stays over water, it will likely maintain some organization and strength. Because the difference in track leading to these scenarios is so subtle, it is impossible to know exactly what will happen toward the end of the week.
In either case, a strong dip in the jet stream is forecast to dive down over the Gulf about Friday and create a path to the north. Will a decently organized Cristobal take that path? Or will the jet-stream dip kill off the Gyre, scooping up the moisture from Cristobal and the Gyre, and form another system, which may not be fully tropical? Or something else? It’s impossible to know at this point.
As the National Hurricane Center acknowledges, there is high confidence in the forecast for the next couple days, but after that there are too many moving parts to know what will happen.
While it does not appear that a northward-moving system would directly impact Peninsula Florida, it’s reasonably likely that tropical moisture will get pulled north with the system, whatever form it takes, which will affect our weather.
In any case, the western half of the Gulf of Mexico is an Area to Watch late in the week and through the weekend.
Needless to say, the Hurricane Season is off to an active start. In recent years, on average, the first named storm hasn’t come along until June 22. The average date for the third storm to show up is August 4th. But still, all this close-to-home activity doesn’t say anything about the state of the tropics in August, September, and October.
Mother Nature is simply reminding us that Hurricane Season is here, and it’s time for all of us to figure out what we would do if a hurricane threatens this year. Living in Florida means living with hurricanes. There is nothing to do but to be prepared.