Jump to content
  • Member Statistics

    18,284
    Total Members
    7,904
    Most Online
    happyclam13
    Newest Member
    happyclam13
    Joined

Tropical Depression Nine


WxWatcher007
 Share

Recommended Posts

Tropical Depression Nine Discussion Number   5
NWS National Hurricane Center Miami FL       AL092025
500 PM EDT Sat Sep 27 2025
 
The organization of the depression has not changed much since this 
morning. Some deep convection has flared up this afternoon near the 
estimated center, which appears broad in the 850-mb flight-level 
wind data from the Air Force Hurricane Hunters. The earlier 
scatterometer winds and more recent aircraft data do not suggest the 
system has intensified. The initial intensity is held at 30 kt for 
this advisory.

The center appears to be slightly south and west of previous 
estimates, with an uncertain initial motion of 315/4 kt. Over the 
next couple of days, the system should turn more north-northwestward 
within the flow between an upper trough over the southeast U.S. and 
a subtropical ridge over the Atlantic. This forecast brings the 
depression over the central and northwestern Bahamas through early 
Monday, then toward the southeast U.S. coast by Tuesday. The NHC 
track forecast is very similar to the previous one, with only a 
slight nudge westward based on the initial position adjustments 
during the day. Warm waters and strong upper-level divergence should 
promote strengthening during the next few days, but this could be 
tempered by moderate southerly shear over the system from an 
upper-level trough. The NHC intensity forecast shows steady 
strengthening through early next week, with the system becoming a 
hurricane by 60 h. This prediction lies close to the latest IVCN and 
HCCA aids. 

There is still above-average uncertainty in the details of the 
long-range forecast. In general, the models agree that the presence 
of Hurricane Humberto to the east will result in a weakening of the 
prevailing steering currents, causing the system to slow down and 
meander near the southeast U.S. coast on Tuesday. While the chances 
of a landfall appear lower than yesterday, there are still some 
hurricane regional models and ensemble solutions that show this 
possibility. Given the expected asymmetric storm structure, a risk 
of significant heavy rainfall, storm surge, and wind impacts exists 
for the southeast U.S. coast even if the storm center remains 
offshore. The increased track spread at 96-120 h is related to 
whether the system feels the effects of an amplifying upper-level 
trough behind Humberto over the western Atlantic. While many global 
models show a sharp eastward turn and acceleration away from land, 
the system fails to be captured by the trough in the 12z ECMWF and 
lingers offshore. The NHC track forecast at days 4-5 maintains a 
consensus approach and shows a slower eastward motion, but future 
track adjustments are likely as confidence increases. The system may 
be in close proximity to fronts by the end of the period, so 
extratropical transition could begin around or shortly after day 5.
 
 
KEY MESSAGES:
 
1. The depression is expected to strengthen and bring tropical storm
conditions to portions of the central and northwestern Bahamas
through Sunday night. Tropical storm conditions are also possible
along portions of the east coast of central Florida beginning
Monday, where a Tropical Storm Watch is in effect.
 
2. Rainfall will continue to impact eastern Cuba, Hispaniola, 
Jamaica, and the Bahamas through the weekend, which will likely 
produce flash and urban flooding. Mudslides are possible in the 
higher terrain. 
 
3. There is a significant threat of heavy rainfall early next week 
from portions of the east coast of Florida northward into the 
Carolinas, which could cause flash, urban, and river flooding. 
 
4. The depression is expected to be at or near hurricane intensity 
when it is closest to the southeast U.S. coast early next week, 
where there is a risk of storm surge and wind impacts. Although it 
is too soon to specify the exact location and magnitude of impacts, 
residents should closely monitor the latest forecast updates and 
ensure that they have their hurricane plan in place.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/2100Z 22.2N  76.5W   30 KT  35 MPH
 12H  28/0600Z 23.3N  77.1W   35 KT  40 MPH
 24H  28/1800Z 24.9N  77.6W   45 KT  50 MPH
 36H  29/0600Z 26.7N  78.1W   55 KT  65 MPH
 48H  29/1800Z 28.5N  78.6W   60 KT  70 MPH
 60H  30/0600Z 30.0N  78.8W   65 KT  75 MPH
 72H  30/1800Z 30.8N  78.6W   65 KT  75 MPH
 96H  01/1800Z 31.1N  76.8W   65 KT  75 MPH
120H  02/1800Z 31.5N  74.0W   60 KT  70 MPH
 
$$
Forecaster Reinhart
Link to comment
Share on other sites

1 hour ago, blueheels2 said:

I’m disappointed I wanted to get a good soaking rain out of this.

Same - specifically and only over the grounds of the US Whitewater Center in CLT so that I don't have to run a 50k trail race.

Link to comment
Share on other sites

Although the convection is weak and disorganized, recon is now showing a much more well defined circulation, which if it holds will allow for gradual organization. 

mK5pdzj.png

Note how much tighter the circulation is in the image above, compared to some of the recon images posted earlier. You can also see a pocket of slightly stronger winds on the far eastern side of the system. Below you can see how the circulation is becoming better organized. Slowly. 

iP9aKcE.gif

Convection is weak, but there has been some firing of stronger thunderstorms near the center. 

2L55cMD.gif

Shear has remained an issue through the day, but analysis shows that the shear may be abating, especially near the center. 

ACAuve3.gif

TD9 is in one of the best thermal environments in the entire Atlantic, so if it can start generating deep convection over its tightening center it should gradually intensify. 

LP1RTRr.png

While I am posting the SHIPS here, there looks to have been a bit of an uptick from hurricane guidance in overall intensity over the coming days. That's something we'll need to pay attention to, with the caveat that the trough and possible dry air will continue to lurk and will likely put a cap on intensity. 

P9BzWlK.png

 

Now for the track. There is increasing confidence that future Imelda will in fact turn away from the SE coast, but there is still a lot of uncertainty on how close the center gets to the coast and critically, the speed of the turn. Most guidance now turns the system away from the coast and accelerates it east into an Humberto created weakness. 

HVtsZdK.png

0htmDE6.png

But within this evolving track forecast there are two diverging camps. The first, and most numerous, is one that easily follows Humberto out to sea. The second, which is led by the Euro and Euro AI to an extent, turns the system more slowly and allows a ridge to build over the top and close the escape route. The result is Imelda being turned back toward the coast. 

6wn2fEf.png

There aren't a lot of members that are held back, but the ones that do are pretty strong. 

L0qAwKy.png

So while it very well may be the case that this does turn and accelerate out to sea, there's still uncertainty. Remember, the models struggled with this inside of 100 hours. I'm not sure we should be locking in anything 5+ days out yet. Additional recon and finally having a well defined center should help with both track and intensity guidance. 

Finally, just because this is likely to stay offshore initially, that doesn't mean no impacts. TS force winds, coastal flooding, and flash flooding are still squarely hazards for coastal FL, GA, and the Carolinas. Just slight track changes could make the flood threat more impactful along the coast. 

X2tAe4d.gif

  • Like 4
  • Thanks 2
Link to comment
Share on other sites

Base on my amateur eyes, and satellite photos, Nine's center looks very broad and disorganized right now. There is a closed low, but it is still a big mess. Wind shear seems to have let up a bit, but still exists. Plus Humberto is not far away, moving WNW at 10mph, at : 22.9°N 61.1°W. 

Nine is at Location: 22.4°N 76.5°W moving NW at 5mph. Can someone confirm on latest satellite that it looks more like NNW at this time as the cold front to the north west is blocking it from getting to the coast. 

wg8shr.GIF

 

 

Link to comment
Share on other sites

9 minutes ago, Wannabehippie said:

Base on my amateur eyes, and satellite photos, Nine's center looks very broad and disorganized right now. There is a closed low, but it is still a big mess. Wind shear seems to have let up a bit, but still exists. Plus Humberto is not far away, moving WNW at 10mph, at : 22.9°N 61.1°W. 

Nine is at Location: 22.4°N 76.5°W moving NW at 5mph. Can someone confirm on latest satellite that it looks more like NNW at this time as the cold front to the north west is blocking it from getting to the coast. 

wg8shr.GIF

 

 

I don’t think it’s broad looking at the sharper wind shifts on recon, but it is weak—probably because it’s only now starting to tighten up and convection is limited. 

Link to comment
Share on other sites

13 minutes ago, Wannabehippie said:

Base on my amateur eyes, and satellite photos, Nine's center looks very broad and disorganized right now. There is a closed low, but it is still a big mess. Wind shear seems to have let up a bit, but still exists. Plus Humberto is not far away, moving WNW at 10mph, at : 22.9°N 61.1°W. 

Nine is at Location: 22.4°N 76.5°W moving NW at 5mph. Can someone confirm on latest satellite that it looks more like NNW at this time as the cold front to the north west is blocking it from getting to the coast. 

wg8shr.GIF

 

 

Per recon, it hasn’t been moving NNW. Actually, there apparently was just a reformation of the weak center slightly to the SE per this. Overall, it has moved very little today so far:

IMG_4666.thumb.png.6b142eee762d66dd3b380024f8c51b58.png

  • 100% 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...