June 20, 2023 Outlook: Extreme sea temperatures are fueling Bret and a second Atlantic system

The National Hurricane Center began issuing advisories for Tropical Storm Bret on Monday, and we’re also tracking a second system not far behind that likely will also become a named storm. Both of these systems have formed in the “main development region” of the Atlantic where tropical systems often begin their lifetimes. However, the season for storm formation in the main development region typically does not kick off until August.

So what’s happening out there? Well, it’s blazing hot.

Graphic showing temperature anomalies in the main development region. (Ben Noll)

Ben Noll, a New Zealand meteorologist, noted on Monday that sea surface temperatures in the main development region are the warmest they’ve been on record for June. In fact, the seas are as warm now as they typically are in late August or September, when the Atlantic hurricane starts to peak. That’s one reason why we’re seeing a spate of early season activity.

A second chart from Ben is equally concerning, as it shows temperatures in this region presently exceeding those of the 2005 and 2010 Atlantic hurricane seasons, both of which produced frenetic activity. The 2005 season remains the most active year in my lifetime, and Gulf Coast residents will doubtlessly remember Katrina, Rita, and Wilma all reaching Category 5 status in the Gulf of Mexico.

Well, that’s concerning. (Ben Noll)

Warm seas are not the only factor in storm formation, of course. This year, with El Niño in the Pacific, we can have some hope that wind shear will counteract the formation of storms. But worryingly, so far, warm seas appear to be winning out against El Niño. I have to say that I am starting to get mildly concerned about what is to come this year, particularly in August and September.

One-sentence summary

We’re tracking Tropical Storm Brett as well as Invest 93L, which has been given an 80 percent chance of developing this week into a depression or named storms in the coming days.

Brett is being followed by a system that would be named Cindy, if it develops. (National Hurricane Center)

Happening now: The stage is set for Bret, with a possible encore

Here’s what we know about the two tropical systems out there.

Tropical Storm Bret

First of all, with apologies to fans of George Brett, this system has just one “t.” After forming on Monday the storm has changed little in intensity overnight, with sustained winds of 40 mph. This is likely due to some moderate wind shear nearby. Not enough to break the storm apart, but enough to keep its organization at bay.

The system has about three days to get its act together before shear is expected to increase, in which case Bret should start to weaken. At present the National Hurricane Center brings Bret to hurricane strength briefly, before winding it back down on Thursday night as it approaches the Lesser Antilles islands in the Caribbean Sea.

Bret is bound for the Caribbean Sea. (National Hurricane Center)

No one wants to see a tropical storm headed their way, and Bret is something that people in the Caribbean Islands, including Puerto Rico, the Dominican Republic, and Cuba will want to keep an eye on. Damaging winds and heavy rainfall are definitely possible with Bret later this week or weekend, although I don’t think we’re looking at a situation where this storm really blows up. My biggest concern is flooding, but it’s not really possible to say where the heaviest rain will occur. We should have a better handle on the overall threat tomorrow morning.

Invest 93L

Much like its predecessor, Bret, how well this tropical system gets organized is tied up with where it goes, with a better organized disturbance likely turning northwest before the Caribbean and a less organized one likely following 92L to the west and into the islands. For now the most likely outcome, I believe, is that this system turns north before reaching the Caribbean Sea. That would be best for all concerned, except maybe for the fish.

The medium range (days 6-10): And then there were three?

As Matt noted on Monday, there are some signs in the models that yet another disturbance will emerge off Africa soon, and that this may be something that could develop over the weekend or next week. However the models don’t appear too excited about this system becoming a big deal, likely due to a fairly uninviting environment overall for development. Certainly at The Eyewall we’re rooting for shear to have its day.

Fantasyland (beyond day 10): Possibly calmer to end June

After this present spate of activity, the overall tropics may turn a bit quieter to end the month and start July.


Arlene comes and Arlene goes

Tropical Depression 2 was upgraded to Tropical Storm Arlene yesterday afternoon, and as I am writing this, Arlene is on its way out. Here now, a quick recap of 2023’s first named storm.

No, but seriously, Arlene is on the way to dissipation later today or tomorrow. Looking at a satellite image today, Arlene is more curious looking than menacing.

Tropical Storm Arlene is a swirling area of clouds and isolated thunderstorms at this point, and should be downgraded to a depression or remnant low later today. (Tropical Tidbits)

There are some thunderstorms still on the far northeast side of Arlene, but that’s about all right now. The center is clearly visible, but without thunderstorms around that center, it’s clearly evident that shear and dry air are doing work. A forecast map from the GFS model that shows wind speed and direction (indicated by the little barbs on the map) and relative humidity in the upper atmosphere (brown = drier air and green = more moisture) shows that Arlene is in a very dry, very hostile (windy) environment aloft. This is a good recipe for disorganization, and as such, Arlene’s end game is clear.

Arlene is surrounded by dry air and under a high wind shear environment, which means it’s inevitably about to fall apart. (Tropical Tidbits)

So we’ll call that a wrap on Arlene for all intents and purposes.

Florida rainfall chances

For Florida, which on the map above is covered in higher moisture, there will continue to be rounds of thunderstorms today, and the National Weather Service in Miami continues the flood watch from Miami-Dade through Palm Beach Counties and around Lake Okeechobee. The heaviest rains on Friday fell north and west of the lake and between Tampa and Orlando.

Forecast rainfall through Monday morning in Florida, with isolated heavy rain likely between the Keys, Miami, and Tampa.

Rain totals as forecast above will be quite variable (and may be placed a bit differently than shown in the forecast). Some areas may see a quarter to half-inch or less, while others could easily see 2-4 inches of rain between now and Monday, so watch for ponding and areas of localized flash flooding, especially in spots that have seen a good bit of rainfall this week. Also, as is occasionally the case with tropical thunderstorms, we could see reports of waterspouts or even some isolated strong to severe storms today or tomorrow in South Florida.

Otherwise, that’s all to discuss. We’ll be back on Monday with our daily tropical update and a look at some seasonal forecasts for this year. Enjoy the weekend!

Tropical Depression 2 struggling over the open Gulf; isolated heavy rains for Florida

Good morning, and welcome again to The Eyewall, where we provide hype-free, measured coverage of the Atlantic tropics all season long.

Today, we wake up to Tropical Depression 2 in the Gulf no better organized than it was yesterday evening, and struggling somewhat. TD 2 itself is more of a meteorological curiosity than anything else, although heavy rain continues to be possible in portions of the Florida Peninsula.

Tropical Depression 2’s center is displaced south and west of the main cluster of storms, indicating a poorly organized, heavily sheared system. (Tropical Tidbits)

One-sentence summary

Tropical Depression 2 is expected to drift south toward Cuba and dissipate this weekend, and although it may still technically attain tropical storm status and will aid in Florida storms, it is not a direct threat to anyone.

All things Tropical Depression 2: Meteorological curiosities and rain in Florida

Again, the system itself is not really an issue for anyone. It’s fairly weak and over open water. From the satellite loop above, you can actually sort of see the center of TD 2, exposed to the south and west of the green-yellow-orange colors, which are thunderstorms south of the Panhandle. That’s an indication of an unhealthy, sheared system. As visible satellite imagery becomes available today, we may see this enter “naked swirl” territory (where the center is completely displaced from any storms). Still, per the National Hurricane Center 4 AM CT discussion, TD 2 may technically be close to being a tropical storm. All you need is an area of 34 knot (39 mph) sustained wind to technically classify it, hence this is mostly a meteorological curiosity at this point.

At a high level, the forecast track for TD2 is mostly unchanged versus yesterday. It drifts south in the Gulf before dissipating near Cuba on Sunday.

The curious track of TD dissipates it near Cuba this weekend. (NHC)

Several of you have mentioned, “You know, that’s a bizarre track. Is that normal?” The answer is “No, it’s not technically normal.” It is certainly funky, but often (especially in early season), storms can take these weird tracks. All tropical storm tracks are generally a function of the environment around them. And if we look about 20,000 feet (at what meteorologists call the 500 mb level) over our heads at what’s happening, it becomes fairly clear to see why TD 2 takes this type of track.

The 500 mb (~20,000 feet up) map shows that TD 2 is being steered by a strong north or northwesterly push aloft, which helps to drive it southward. (Tropical Tidbits)

The red “L” in the middle of the map, which is a forecast of 500 mb vorticity this afternoon is the approximate location of TD 2. The pattern features strong northerly or northwesterly winds which help to direct the western portion of TD 2’s broader circulation south. Steering currents over Florida and Georgia are fairly weak, so there’s little influence from there, hence all this northerly push pretty much forces TD 2 southward. Winds out of the southwest across Cuba and into the Bahamas help to give it that little eastern turn late, but of course by then, it will have pretty much dissipated.

So, TD 2 is not a direct threat to any land, but the convoluted pattern around the system will help to continue aiding rainfall in parts of Florida today. Flood watches continue for the southeast coast, from Miami-Dade through Palm Beach Counties and around Lake Okeechobee. Over the last three days there have been isolated spots seeing in excess of 3 to 5 inches of rain.

Rainfall over the last three days has led to a couple “bullseyes” (yellow & orange) around South Florida. (NSSL MRMS)

Because of this, and because of the potential that some showers and storms could produce a few more inches of rain and lead to flash flooding, the flood watch continues.

A flood watch continues for much of South Florida, with another 1 to 2 inches of rain (or a bit more) possible in isolated spots today. (NWS Miami)

Not all of South Florida will see heavy rain, but some will today and perhaps even Saturday too before things start to return to normal next week and TD 2 experiences its demise.

Medium range (days 6 through 10): Nothing doing

The day 6 through 10 period looks pretty quiet. I would expect the majority of the basin will be covered by decent wind shear, which acts to limit storm development. In addition, it looks like we’re in an unfavorable upper level pattern overall, with more sinking air across the basin as well. It is June, after all, so that shouldn’t come as a surprise.

Fantasyland (beyond day 10): Also quiet

This quiet will probably extend firmly through mid-June and possibly (hopefully?) into late June. Nothing is showing up in the long range that should ruffle any feathers right now.

We’ll be back tomorrow with a quick update on TD 2. Look for our normal daily update on Monday morning, where we’ll tackle what is normal for June as the season begins.

Tropical Depression 2 forms in the eastern Gulf of Mexico; no change to expected impacts

Good evening! Welcome again to The Eyewall. We did not expect to be actually covering a storm on day one, but here we are. This is the type of coverage you’ll get with every Atlantic system on this site.

Based on data collected from Air Force Reserve Hurricane Hunter aircraft this afternoon, Invest 91L was classified as Tropical Depression 2 in the eastern Gulf of Mexico.

Wait– Why TD 2? What happened to TD 1?

Back in mid-May, the National Hurricane Center (NHC) determined that a subtropical storm formed off New England back <checks notes> January. Thus, when the 2023 season is in the books, that storm will have the honor of being Storm 1. However, it did not take on the name Arlene since it was classified after the fact. Thus, since this is the second cyclone of the season, it is classified as TD 2. If it becomes a tropical storm, it will be named Arlene. Got it? Good.

Where will TD 2 go?

The official forecast from the NHC looks good. It’s headed south.

TD 2 will track due south over the next couple days, possibly strengthening to a tropical storm before dissipating near Cuba this weekend. (NOAA)

This system is unlikely to maintain status long enough to make landfall anywhere, so there are no watches or warnings posted for any coastlines. TD 2 will drift southward through Saturday before likely dissipating on Sunday (if not sooner) near Cuba.

What impacts should we expect? Florida rain!

As we noted earlier today, the primary thing to watch will be rainfall in the Florida Peninsula. Hardest hit so far today has been central Brevard County in Florida, where radar estimates 3-5″ of rain has fallen. Also, the north side of the Tampa Bay area has seen some heavy rain as well. The map below shows rain totals since about 5 AM today for places that have received over 1.5″ of rainfall.

Click to enlarge rainfall totals exceeding 1.5″ so far today across central Florida. (NOAA)

Radar shows pockets of heavy rain extending from the Tampa area south and east across the Peninsula to near Lake Okeechobee before things tail off some. There are also very heavy storms over Delray Beach on the east coast, up through Boynton Beach as well.

Radar through 5:40 PM ET shows areas of heavy rain and lightning from near Tampa south and east to Lake Okeechobee. (Weathernerds.org)

The bottom line in all this? Localized flash flooding is possible. You can see from the rain totals that some areas have seen manageable rain so far. Others have seen up near 5″ the last couple days. Those areas will be most sensitive to flooding, and that’s why there’s a flood watch for South Florida. More showers and storms will be likely tomorrow before things settle down a bit.

The final word?

TD 2 may briefly become a tropical storm tonight or tomorrow before it drifts south toward Cuba and dissipates this weekend. The main issue will be heavy rain and localized flash flooding across the Florida Peninsula, as well as perhaps in portions of Cuba (Havana has seen some very heavy rain today). But it’s likely that there will be little trace of TD 2 left by Sunday.

More in the morning!