The weather, currently.
There are two areas that may develop into tropical storms in the next couple of days. One is in the middle of the Atlantic and will be no threat to land. But the area developing north of Puerto Rico is not only likely to develop, but to track westward toward the Bahamas and Florida.
First, let's look at history. Is this a general area of concern this late in the season? Sure is........
There haven't been many named storms in November, but the area between the Bahamas and Puerto Rico is in the "potential development zone", as I call it.
There have been fewer than 10 tropical cyclones that developed in the area we're watching in the past 175 years, but it has happened (compare with the Gulf of Mexico, where hardly anything has developed).
Next, are water temperatures warm enough to support tropical development? Yup.
Water temperatures are around 82° in that area, and the warmth extends deep enough to have significant "ocean heat content" (which is more important than the surface water temperature alone). In fact, the OHC is near record high levels in this area at this time of year.
The main things preventing tropical formation have been wind shear and dry air. The wind shear was high for hundreds of miles around the Bahamas on Friday. But it isn't high anymore.
Look at the difference between Friday (above) and Sunday (below).
There is a lot of dry air surrounding the developing storm. That is a clear sign of LOW pressure higher up in the atmosphere. So, it looks like any initial development wouldn't be totally "tropical" but "subtropical" instead. This happens frequently this time of year north of the Caribbean. Some of those "subtropical" storms become "tropical" after days spinning over that warm water and low wind shear.
Here is why there is concern that not only will this system eventually develop, but it would start moving toward Florida this week. The clues are (as usual) higher up in the atmosphere.
This was the average upper-air pattern Sunday, Nov. 6 from the world's best-the European model. Extreme patterns like this always get my attention. Unusual patterns lead to unusual weather, and sometimes extreme patterns lead to extreme weather.
First, in the upper right is the pattern around the remnants of the monster former-hurricane Martin. Extremely LOW pressure, and not moving much (part of the overall blocking pattern).
Second, an extreme area of HIGH pressure centered just off the Northeast U.S. coast.
And third, an unusual LOW pressure centered near the Bahamas and Hispaniola.
The combination of #2 and #3 is a classic example of a "Rex Block", a type of "blocking pattern" that can lead to extreme weather in some places. Below is an example from The National Weather Service:
Does the above example look like the European model Sunday? Sure does. Now, how will this pattern change over the next few days? Below is the forecast from the same model FOUR DAYS LATER (Thursday). It's a similar pattern-just shifted WEST. Since weather systems in this part of the world usually move west to east, the forecast pattern is called a "RETROGRADE" (or backwards). The HIGH and LOW both move westward.
So, what happens if a tropical or subtropical LOW develops? It gets forced to move to the WEST toward Florida. And that's exactly what the European model is suggesting (and has been suggesting this for days!)
The European model is run 51 times, with slightly different initial conditions. These are called "ensembles". The maps below show the tiny red numbers indicating centers of LOW-pressure Monday and then Thursday. When these ensemble members are close to each other, the confidence increases that something close to this will indeed happen. And there is amazing agreement of some sort of LOW in the Florida area by Wednesday or Thursday.
This does NOT have to turn into a major hurricane (or a hurricane at all) to cause problems. It's not just about how low the lowest pressure is. It's the DIFFERENCE in pressure between the LOW and the HIGH pressure to the north. The bigger the difference, the stronger the winds and the worse coastal flooding gets. Now add the extra high tides with the FULL MOON Tuesday, and there will likely be damage before this is all over. Those with interests in the Bahamas, Florida, and the coasts of Georgia and the Carolinas should stay aware of possible developments.
— Glenn "Hurricane" Schwartz email@example.com
What you need to know, currently.
Currently’s staff reporter, Anna Abraham, is in Sharm El-Sheikh, Egypt, covering COP27 — the 2022 United Nations Climate Change Conference.
Read Anna’s pre-COP coverage about the conference's focus on climate finance, particularly loss and damage finance — or the financial reparations the Global North owes countries most vulnerable to the climate crisis:
“Losses and damages are mounting for communities on the frontlines of the climate crisis, especially for the poorest who have contributed the least to the problem,” Rachel Cleetus, Policy Director, Climate and Energy Program, Union of Concerned Scientists said in a press conference.
“The success of COP27 depends crucially on the United States and other richer nations living up to their responsibilities to meaningfully address Loss and Damage, including delivering a clear near-term pathway for dedicated and ongoing funding.”
Some leaders are stepping up. Denmark, earlier this year, proposed funding $13.2 million to poorer nations for loss and damage. It is the first central government to do so, breaking away from the European Union consensus in the process. At COP26, Scotland pledged $2 million and the Wallonia region of Belgium earmarked $1 million for loss and damage.”
Anna will be on the ground all week interviewing activists and attendees, follow along on in your inbox and on Twitter.