US Weather Center

09/25/2025

THURSDAY TROPICS UPDATE- with Bryan Norcross LATEST COMPUTER FORECASTS SHOW AN INCREASED THREAT TO FLORIDA AND THE SOUTHEAST FROM LIKELY-IMELDA

(LIVE Hurricane Q&A today at 4PM ET. We’ll be LIVE on YouTube, Facebook, TikTok, X, Instagram, and LinkedIn. I’ll be joined by FOX13 Chief Meteorologist Paul Dellegatto from Tampa Bay to answer your question about today’s tropical situation and look back at Hurricane Helene. We’ll look forward to your questions).

INVEST 94L AND LIKELY-IMELDA

Invest 94L is struggling with the tall mountains in the Dominican Republic, but all indications are it will survive as a viable disturbance and move over or near the Bahamas where it will be able to organize. The National Hurricane Center gives the system a very high chance of developing into at least a tropical depression in the next day or two.

The big question is if and when the system strengthens into Tropical Storm Imelda. That timing, assuming it happens, will affect its future track and potential impacts on land.

For clarity, I'm going to refer to Invest 94L as likely-Imelda.

The change from yesterday is that likely-Imelda and Tropical Storm (and eventual Hurricane) Humberto look less likely to get involved with each other in a significant way. Recall that there was concern they might deflect each other in some impossible-to-predict way.

The higher-odds scenario now is that the large upper-level low pressure system and front that's producing the rain from the Gulf Coast to New England will pick up likely-Imelda and pull it north. If this happens, likely-Imelda and Humberto maintain enough distance from each other that they don’t interact.

In this scenario, after potentially brushing South Florida, Tropical Storm or Hurricane Imelda becomes a threat to the Georgia or Carolina coast early in the week. In addition, the moisture combined with the front could cause dangerous flooding in the Appalachians later next week.

That's not the only potential scenario on the board, however. If the Invest gets torn up by the mountains of the Dominican Republic and takes longer to form, the system could stall over the Bahamas or near South Florida.

Also, there's the best-case possibility that after moving north offshore of Florida for a while, likely-Imelda gets scooped by the big upper low and follows likely-Hurricane Humberto out to sea. In this scenario, Bermuda will have to watch both storms.

These last two scenarios are certainly possible, but appear to have lower odds than the idea that likely-Imelda will proceed apace to the north.

The bottom line is that everybody from South Florida to the Carolinas and Virginia, including the mountain areas, should stay in touch with the latest developments. And it’s important to remember that forecasts for just-developing systems are always subject to large errors and are likely to change.

Hopefully the forecast will come into better focus tomorrow after eventual-Imelda clears the mountains and is over or near the southeastern Bahamas. But if it looks like the scenario that shows likely-Imelda coming close to South Florida then making a beeline for the Georgia or Carolina coast is going to develop, it will happen fairly fast. The current schedule of that scenario has the storm making landfall late Monday or early Tuesday.

TROPICAL STORM HUMBERTO

Humberto is forecast to reach hurricane strength in a couple of days and eventually reach Category 3 strength. Some computer forecasts show it getting even stronger. Residents of Bermuda will have to once again stay informed.

HURRICANE GABRIELLE

The storm is barreling toward the Azores in the eastern Atlantic. It's very rare for a hurricane to reach those islands, but this one started out strong enough that even with the weakening over cooler water, it's still expected to be a strong storm when it moves through the island chain early tomorrow their time.

A weaker version of the storm without its tropical characteristics is forecast to impact Portugal over the weekend.

09/25/2025

2:00pm Tropics update- A tropical wave near Turks and Caicos is likely to become the Atlantic's next tropical depression or storm by this weekend as it travels northwest toward the Bahamas.

The long term track remains uncertain so the entire Southeast US coast should continue to monitor.

NWS National Hurricane Center Miami FL
200 PM EDT Thu Sep 25 2025

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane Gabrielle, located several hundred miles west of the Azores, and on
Tropical Storm Humberto, over the subtropical central Atlantic.

1. Central Caribbean Sea and Southwestern Atlantic (AL94): Showers and thunderstorms are increasing in association with a tropical wave located near Hispaniola and the Turks and Caicos
Islands. An area of low pressure is expected to form along the wave tonight or early Friday when it moves near the southeast
Bahamas. This low is expected to become a tropical depression when it is in the vicinity of the central and northwest Bahamas late Friday or over the weekend and then track northwestward or northward over the southwestern Atlantic.

Interests in the Dominican Republic, Haiti, the Turks and Caicos Islands, and the Bahamas should monitor the progress of this
system. Regardless of development, heavy rains and gusty winds are likely across that region during the next couple of days. While there is significant uncertainty in the long-range track and intensity of the system, the chances of wind, rainfall, and storm surge impacts for a portion of the southeast U.S. coast are increasing. Interests in that area should monitor the progress of
the system.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...90 percent.

09/24/2025

11:00pm advisory for Tropical Storm Humberto...

In the days ahead we could see the Fujiwhara effect take place. This is when 2 systems get so close together that one absorbs the other. The absorbing one does not get any bigger/stronger. It's named after Japanese meteorologist Sakuhei Fujiwhara who first decribed the phenomenon

Tropical Storm Humberto Advisory Number 2
NWS National Hurricane Center Miami FL
1100 PM AST Wed Sep 24 2025
..HUMBERTO EXPECTED TO STRENGTHEN DURING THE COMING DAYS...

SUMMARY OF 1100 PM AST...0300 UTC...

INFORMATION/LOCATION...
20.7N 55.8W ABOUT 505 MI...815 KM ENE OF THE NORTHERN LEEWARD ISLANDS MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H PRESENT MOVEMENT...WNW OR 300 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES

DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Tropical Storm Humberto was located near latitude 20.7 North, longitude 55.8 West. Humberto is moving toward the west-northwest near 12 mph (19 km/h). A west-northwest to northwest motion is expected over the next several days with a slower forward speed. Maximum sustained winds have increased near 45 mph (75 km/h) with higher gusts. Steady strengthening is forecast during the next several days.Tropical-storm-force winds extend outward up to 105 miles (165 km) from the center. The estimated minimum central pressure is 1007 mb (29.74 inches).

09/24/2025

8 PM Tropics UPDATE on a wave currently near Puerto Rico. Formation Chances are "medium" thru Friday, then high into weekend (somewhere in red-shaded area). NHC says interests in the Bahamas should monitor the progress of the system.

NWS National Hurricane Center Miami FL
800 PM EDT Wed Sep 24 2025

For the North Atlantic...Caribbean Sea and the Gulf of America:

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane Gabrielle, located over the central subtropical Atlantic, and on
newly formed Tropical Storm Humberto, located several hundred miles east-northeast of the northern Leeward Islands.

1. Eastern Caribbean Sea (AL94):
Showers and thunderstorms have become better organized since yesterday in association with a tropical wave centered near Puerto Rico. This wave is expected to move west-northwestward around 10 to 15 mph, spreading heavy rainfall and gusty winds across Puerto Rico and the Dominican Republic through early tomorrow. The system is then expected to slow down and turn northwestward when it reaches the southwestern Atlantic. A tropical depression is likely
to form when the disturbance is in the vicinity of the Bahamas late this week. Interests in Puerto Rico, the Dominican Republic, the Turks and Caicos Islands, and the Bahamas should monitor the progress of this system.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 7 days...high...80 percent.

09/24/2025

Heavy to excessive rainfall Wednesday may bring areas of flash and urban flooding over portions of the Ohio and Tennessee Valleys. In Arizona and New Mexico, heavy to excessive rainfall from monsoon thunderstorms may bring isolated flash and urban flooding Thursday into Saturday.

09/24/2025

8 PM Tropics Update: NHC has raised the odds of a tropical depression forming in the red-highlighted area. There's now a 70% (high chance) of a tropical disturbance in the vicinity of the Bahamas, later this week.

The second tropical wave tagged with INVEST 93-L Has a good chance for development in the days ahead. NHC is giving it a 90% chance as it moves W/NW.

NWS National Hurricane Center Miami FL
800 PM EDT Tue Sep 23 2025

For the North Atlantic...Caribbean Sea and the Gulf of America:

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Gabrielle, located over the central subtropical Atlantic.

1. Central and Western Tropical Atlantic (AL93):
Shower and thunderstorm activity associated with a tropical wave located about 750 miles east of the Leeward Islands has become
better organized since yesterday. Environmental conditions are forecast to be favorable for further development, and a tropical depression is likely to form during the next couple of days while the system moves west-northwestward to northwestward into the western tropical Atlantic, well north of the Leeward Islands.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...90 percent.

2. Eastern Caribbean Sea (AL94):
A tropical wave over the extreme northeastern Caribbean Sea continues to produce a large area of disorganized showers, thunderstorms and gusty winds across much of the Windward and
Leeward Islands. This wave is expected to move west-northwestward at 15 to 20 mph, spreading heavy rainfall and gusty winds into
Puerto Rico and the Virgin Islands tonight and Wednesday, and across the Dominican Republic beginning late Wednesday. The system is then
expected to slow down and turn northwestward when it reaches the southwestern Atlantic in a couple of days. Environmental conditions
are forecast to be more conducive for development late this week, and a tropical depression is likely to form when the disturbance is in the vicinity of the Bahamas. Interests in the Virgin Islands, Puerto Rico, the Dominican Republic, the Turks and Caicos Islands, and the Bahamas should monitor the progress of this system.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...high...70 percent.

09/23/2025

TUESDAY TROPICS UPDATE - WITH Bryan Norcross DISTURBANCES TO WATCH FOR FLORIDA, THE SOUTHEAST U.S., AND BERMUDA

As Hurricane Gabrielle accelerates away from Bermuda, our attention turns to two tropical disturbances (tagged Invest 93l and 94L) east of the Caribbean. Both have a good chance of developing late in the week or over the weekend. Systems designated “invests” are just disturbances, but they have sufficient organization that the NHC can run specialized computer models and analyses on them.

RED DISTURBANCE – INVEST 93L

Invest 93L is a large disturbance embedded in a cloud of dry air and Saharan dust, which is slowing its development. There is a strong consensus in the various computer forecasts that the system will break free of the dust, however, as it tracks north in the general direction of Bermuda. The National Hurricane Center has followed suit and has the odds of development in the very high range.

An unusually high percentage of the potential tracks show the system developing into a large, strong hurricane in the general vicinity of Bermuda in about a week. Everybody on the island should stay in close touch with the forecasts once the system develops.

The next two names on the list are Humberto and Imelda. Unless something unexpected happens with the orange disturbance (Invest 94L), and it suddenly develops, the red disturbance (93L) will become Tropical Storm Humberto in a few days.

ORANGE DISTURBANCE – INVEST 94L

Invest 94L is finally breaking free of the hostile upper winds emanating from Hurricane Gabrielle. The weather pattern is becoming increasingly conducive to the system organizing.

It’s moving over the northeastern Caribbean islands, however, and will reach the Virgin Islands and Puerto Rico tomorrow. It's unlikely to organize into more than a gusty moisture surge over the islands, but everybody should stay in touch with the latest updates.

Flooding has been a concern on Puerto Rico with recent heavy rain, which will increase with this additional deep tropical moisture. El Yunque Peak, the 3,500-foot mountain in the center of the island, will be a deterrent to the system developing quickly, but will also enhance the rainfall on its windward slopes.

When the disturbance arrives over or near the southeastern Bahamas about Thursday, there is a reasonable consensus in the computer forecasts that the system will begin to organize. The National Hurricane Center gives 94L a medium chance of developing into at least a tropical depression.

Once the system is over or near the Bahamas in a few days, it is forecast to slow down, and things get tricky. Most computer forecasts show the depression or storm tracking north off the Florida coast in the general direction of North Carolina. But enough forecasts curl it toward the coast into Florida, Georgia, or South Carolina, that everyone is going to have to watch it closely.

The weather pattern is forecast to be marginal for significant strengthening, but any storm tracking over warm, deep water of the Gulf Stream has plenty of fuel to intensify.

The time frame for potential impact with the coast would be late in the weekend or early next week.

A fundamental rule of forecasting is that forecasts for disorganized, just-organizing, or slow-moving systems are subject to larger than normal errors and subject to change. This system looks to check two of those boxes.

For now, there's nothing to do but watch for developments.

The exclusive FOX Weather Tropical Threat analysis, which combines the forecast arrays from the European, U.S. GFS, and Google DeepMind AI models, shows the relatively high-certainty path of 93L in the general direction of Bermuda, and the less-certain development zone of 94L over the Bahamas and along the east coast of Florida and the Southeast.

The color simply tells you the areas with the highest likelihood of at least a tropical depression forming or tracking.

HURRICANE GABRIELLE

On its current forecast track, Hurricane Gabrielle will be in the general vicinity of the Azores late Thursday or Friday. Residents there should stay in close touch with the latest forecasts and local instructions.

Gabrielle is currently a powerful Category 4 storm but is forecast to start weakening tomorrow under more hostile upper winds and over cooler water. But it is expected to still be a formidable storm when it arrives near the Azores. The remnants are forecast to be near northwestern Spain and Portugal early next week.

09/23/2025

With today being the end of astronomical summer, here is a look back at the highest temperature of the summer of 2025 at various locations. Many locations recorded their highest reading in late June or late July, although a few locations reached it at other points in the summer.

09/22/2025

2:00pm Monday Tropics update...

NWS National Hurricane Center Miami FL
200 PM EDT Mon Sep 22 2025

For the North Atlantic...Caribbean Sea and the Gulf of America:

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane Gabrielle, located over the central subtropical Atlantic.

1. Central Tropical Atlantic:
Shower and thunderstorm activity associated with a tropical wave located about midway between the Lesser Antilles and the Cabo Verde Islands continues to increase. Environmental conditions are forecast to become more favorable for development by tomorrow, and a tropical depression is likely to form on Wednesday or Thursday while the system moves west-northwestward to northwestward across the central Atlantic.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...high...80 percent.

2. East of the Leeward Islands:
A tropical wave located about 300 miles east of the Leeward Islands is producing disorganized showers and thunderstorms. Environmental conditions appear marginally conducive for some development over the next few days as the wave moves quickly westward to west-northwestward at 15 to 20 mph. By the latter part of this week, the system is expected to slow down and turn more northwestward, and a tropical depression could form late this week when the system is over the southwestern Atlantic Ocean or near the Bahamas. Regardless of development, gusty winds and heavy rainfall are expected to affect portions of the Leeward Islands late tonight and Tuesday and near Puerto Rico late Tuesday and Wednesday.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...50 percent.

09/22/2025

MONDAY TROPICS UPDATE- WITH Bryan Norcross

GABRIELLE BRUSHING BERMUDA AS LONG-RANGE FORECASTS SHOW MORE STORMS ARE LIKELY

Hurricane Gabrielle will make its closest approach to Bermuda later today. The center is forecast to track more than 150 miles offshore, but the storm will cause large, dangerous swells to impact the island. Winds are not expected to be dangerously strong.

Some swells are reaching the U.S. East Coast. The ocean will begin to calm down tomorrow as Gabrielle accelerates into the open ocean. The Azores Islands off Portugal will have to keep an eye on it for later in the week.

DEVELOPING TROPICAL DISTURBANCES

The National Hurricane Center reintroduced a disturbance we were watching last week - the orange X on the map. I’m calling it Disturbance #2, just to keep them straight. This was the one we were concerned about because it was forecast to move farther west and perhaps turn north in a threatening way.

Orange means that the NHC is giving the system a medium chance of developing into a tropical depression over the next several days. There is no consensus in the various computer forecast models on what’s going to happen, but many options include the system organizing. The possibilities range from a significant threat to the Southeast to little if any development.

Disturbance #2 disappeared from the map late last week because the dry air obliterated its clouds and thunderstorms, and it was impossible to follow. The energy from the disturbance continued west, however.

Now, thunderstorms have redeveloped, and the computer forecast models are tracking the system once again.

Another change since last week is that now there is a strong consensus that a sharp dip in the jet stream is going to plunge into the Southeast this week. The jet stream dip will tend to keep any storms that try to get near the U.S. East Coast offshore and push them off to the north… at least through this week.

About next weekend, things get murky, however. There is wide disagreement in the long-range forecasts on how the pattern will evolve, and where Disturbance #2 will be in several days.

Will it be pulled north or will it be blocked? Will it develop? Or will it track close to Disturbance #1 and be weakened by the interaction? If it stays weak, it could track into the Caribbean and be pulled north from there.

That's all nearly a week away. Obviously a lot can change in that time. For now, we just have to watch and be aware that something annoying could develop with this system around the weekend.

The red X represents Disturbance #1, a large disturbance with a high chance of developing. For now, that system is embedded in dust and dry air.

As indicated by the large red potential development area, it’s not clear when it will pull itself free, but it’s likely to develop. Many forecasts show it becoming a strong hurricane that, more or less, follows Gabrielle in the general direction of Bermuda.

The exclusive Tropical Threat analysis looks for a consensus among the European, U.S. GFS, and Google DeepMind AI models on where or if systems will develop into at least a tropical depression. You can see that there is high agreement that Disturbance #1 will head north following Gabrielle. For Disturbance #2, the consensus is in low to medium range that a system will develop near the Bahamas. But there is a lot of spread in the possible tracks.

The next two names on the list are Humberto and Imelda. Chances are we’ll use Humberto, and maybe both.

09/21/2025

UPDATE (11 PM) Forecast Cone for Hurricane Gabrielle. Forecast to become a major hurricane east of Bermuda on Monday (late). Gabrielle, then, races away across the northern Atlantic.

Hurricane Gabrielle Advisory Number 20
NWS National Hurricane Center Miami FL
1100 PM AST Sun Sep 21 2025
..GABRIELLE FORECAST TO TURN NORTHWARD SOON.....FORECAST TO RAPIDLY INTENSIFY ON MONDAY...

SUMMARY OF 1100 PM AST...0300 UTC..

INFORMATION/LOCATION...
29.2N 62.2W
ABOUT 265 MI...425 KM SE OF BERMUDA
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...NW OR 325 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...992 MB...29.30 INCHES

WATCHES AND WARNINGS
--------------------
Interests in Bermuda should monitor the progress of Gabrielle.

DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Hurricane Gabrielle was located near latitude 29.2 North, longitude 62.2 West. Gabrielle is moving toward the northwest near 12 mph (19 km/h). A turn toward the north is forecast on Monday, followed by a faster northeastward or east-northeastward motion on Tuesday. On the forecast track, the center of Gabrielle is expected to pass east of Bermuda on Monday evening.

Maximum sustained winds are near 75 mph (120 km/h) with higher gusts. Rapid intensification is forecast over the next day or so, and Gabrielle could become a major hurricane Monday night.

Hurricane-force winds extend outward up to 25 miles (35 km) from the center and tropical-storm-force winds extend outward up to 140 miles (220 km). The estimated minimum central pressure is 992 mb (29.30 inches).

09/21/2025