WxWatcher007

Hurricane Humberto Discussion Number  10
NWS National Hurricane Center Miami FL       AL082025
1100 PM AST Fri Sep 26 2025
 
Humberto has continued to intensify rapidly this evening.  The eye
temperature has increased to 15C and the eyewall white ring (-73C) 
is nearly closed.  A 2137 UTC WSFM-1 HiRes microwave pass indicated 
that a concentric ring was developing about 65 nm from the eye. The 
initial intensity is raised to 125 kt and is close to the UW-CIMSS 
ADT of T6.4 and above the constrained subjective Dvorak intensity 
estimates from TAFB and SAB.
 
All intensity contributions, low shear, warm waters, and ample
mid-level moisture, appear conducive for Humberto to intensify 
rapidly during the next 12-24 hours.  DTOPS guidance indicates 
a high probability of RI during the next 12-24 hours, and the latest
official intensity forecast follows suit, bringing Humberto to a
peak intensity of 140 kt Saturday night.  By the 36 hour period,
however, inner-core fluctuations as a result of eyewall replacement 
cycles (ERC) are possible, and it's difficult to forecast the exact 
timing.  It's worth mentioning, however, that the UW-CIMSS M-PERC 
(Microwave-based Probability of Eyewall Replacement Cycle) 
statistical model is predicting a 61 percent of onset.  By mid-next 
week, increasing vertical shear spreading over Humberto should 
induce a gradual weakening trend.  At the same time, while it passes 
west of Bermuda, a significant expansion in the surface wind field 
will likely occur.  The NHC intensity forecast is just above the 
previous forecast through the 36 hour period, and closely follows a 
blend of the HCCA consensus and the HAFS/HWRF/HMON hurricane models.
 
Humberto has taken a trochoidal jog to the left of the track this
evening, likely due to the rapid intensification event. The initial 
motion is estimated to be slightly south of due west, or 265/6 kt.  
Humberto is expected to move slowly toward the west or 
west-northwest during the next day or so in the easterly steering 
flow provided by mid-tropospheric high pressure located to the north 
of the cyclone and just east of Bermuda.  Around the 48 hour period, 
or Sunday evening, a northwestward turn with some reduction in 
forward speed is forecast while the above-mentioned high pressure 
weakens and shifts eastward.  By day 4, Humberto should commence a 
rather abrupt turn northward and northeastward in response to a 
major shortwave upper-level trough amplifying and moving out of 
northeastern Canada and into the northwestern Atlantic.  The 
official track forecast is located just to the left of the previous 
advisory, primarily due to the initial motion left of track, and 
lies between the HCCA corrected consensus and the Google DeepMind 
ensemble model.
 
NOAA buoy 41044, located about 38 n mi southwest of the center, has 
reported falling pressure,sustained tropical-storm-force winds, 
gusts just below hurricane-force and 17 ft seas.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/0300Z 22.1N  58.7W  125 KT 145 MPH
 12H  27/1200Z 22.2N  59.8W  135 KT 155 MPH
 24H  28/0000Z 22.7N  61.6W  140 KT 160 MPH
 36H  28/1200Z 23.6N  63.5W  135 KT 155 MPH
 48H  29/0000Z 24.8N  65.3W  130 KT 150 MPH
 60H  29/1200Z 26.2N  67.0W  125 KT 145 MPH
 72H  30/0000Z 27.9N  68.2W  115 KT 130 MPH
 96H  01/0000Z 32.1N  68.2W  100 KT 115 MPH
120H  02/0000Z 36.0N  62.0W   90 KT 105 MPH
 
$$
Forecaster Roberts

WOW Humberto now forecast to become a cat 5

2 minutes ago, LeesburgWx said:

Tucked.

Good to see the Euro AI take up the annual challenge of throwing tropical up the bay

5 minutes ago, nycwinter said:

jumping the gun a bit to early..

Yeah we have a long way to go…

Even with this half scan, Humberto is an absolute beast.

26 minutes ago, GaWx said:

18Z Icon remained OTS. If this ends up not hitting the US, keep in mind that both the Icon and UKMET haven’t had even one run so far with anything even that close to a landfall. Those two models were the best with Ian by the way.

It would be an enormous coup, especially considering where the ensembles were. 

30 minutes ago, ineedsnow said:

 

I'm surprised you didn't post the skynet version  

Somebody mentioned Joaquin the other page and man, this might be worse. I don’t think there’s anyone that even has a clue of what this will do. 

It would be an all time win for the second tier models. 

This is truly remarkable uncertainty on the guidance given how close we could be to a landfall. The GFS follows what some ensemble camps have hinted at, but the outcome verbatim is just radically different in impacts and timing compared to recent op runs. This is a very tough system for emergency managers that need to prepare people to take action. 

With Humberto rapidly intensifying today, another MH is on the board. 

Peak Season Forecast (Aug 20-Oct 20)
Named Storms: 10 (3)
Hurricanes: 6 (2)
Major Hurricanes: 3 (2)

Fernand, Gabrielle (MH), Humberto (MH)

Taking a look at our coming PTC. Thanks to @Nibor for showing me how to post larger gif animations. 

You can clearly see both the gradual organization and headwinds for the coming PTC 9. To the north, you can see arc clouds still radiating out of the area, indicating the presence of some dry air. You can also see some of the thunderstorm tops being sheared, although it does look like in recent frames that things may have slackened some.  

It's easier to see the larger scale spin, and recon is on the way to examine how well defined a low level center there is. For a relatively short term forecast, there is still a lot to be figured out. 

13 minutes ago, olafminesaw said:

Pretty grim for a mean

It looks like the ensemble members on balance don’t have that coastal stall. The slower members stay OTS

Don’t look at the specifics. I’m just highlighting the threat of widespread high end rainfall. That signal has been there consistently, even though the axis of heaviest rain has bounced around. 

Note how the ridge above slams the door shut for an escape, even though Humberto is able to initially exert some influence. It leads to a prolific rain event...

2 minutes ago, GaWx said:

Then per other sources it stalls just offshore for 24+ hours

Closer to the coast than 00z, but a departure from the clear landfall at 06z. Humberto is pulling away as the ridge rolls over the top so the escape route probably closes. Still a lot to figure out with not a lot of time. 

3 minutes ago, dendrite said:

Another year of more spider posts than severe. 

Keep this up and it might outdo winter storm posts. 

PTC likely later today

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Fri Sep 26 2025

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

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane 
Humberto, located over the subtropical central Atlantic, and has 
issued the last advisory on Post-Tropical cyclone Gabrielle over 
the northeastern Atlantic. 

Southwestern Atlantic (AL94):
Satellite data and surface observations indicate that a low pressure 
system appears to be forming near eastern Cuba and the southeastern 
Bahamas.  This system is producing a large area of disorganized 
showers and thunderstorms, and gusty winds. Gradual development of 
this system is expected, and it will likely become a tropical 
depression during the next day or so while it moves northwestward or 
northward across the central and northwestern Bahamas.  

Regardless of development, heavy rains and gusty winds are ongoing 
in the Dominican Republic, Haiti, the Turks and Caicos Islands, the 
southeastern Bahamas and eastern Cuba, and are likely to spread 
across the remainder of the Bahamas over the weekend. Interests in 
all of these areas should monitor the progress of the system.  
Tropical storm watches or warnings could be required for portions of 
the Bahamas and advisories on a potential tropical cyclone could be 
issued as early as later today. While there remains considerable 
uncertainty in the long-range track and intensity of the system, 
there is a significant risk of wind, rainfall, and storm surge 
impacts for a portion of the southeast U.S. coast early next week. 
Interests in this area should also monitor the progress of the 
system. 
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

$$
Forecaster Cangialosi/Reinhart/Hagen

1 hour ago, Nibor said:

How did you get a larger gif to post?

2 minutes ago, stormtracker said:

What are you talking aboot? 

The Canadian keeps future Imelda offshore, but the massive ridge over the top blocks its escape and runs it up the coast. 

Funky. 

The Canadian, as usual, is funky.

Just now, NorthHillsWx said:

I’m very worried. This has high end flood potential written all over it even if it stalls just off the coast

Not to mention the onshore flow. A further south track with that flow over Charleston would be very bad. The Low Country is called that for a reason (I used to live in SC).

41 minutes ago, SJonesWX said:

ASATT

All spiders all the time

Exciting times in New England.

You can see pretty easily why the establishment of an inner core matters here. On the 06z GFS run, the core is weaker and less structurally sound, and as a result it’s easier for dry air to get entrained.  

The result is a slowly intensifying storm (take note) on landfall.

12z has a symmetrical core, which not only makes it stronger but closes off the eye from dry air entrainment.

The result is a substantially stronger hurricane that is likely intensifying more robustly on landfall. 

I can’t emphasize enough how important it’ll be to get a well defined LLC so that the models can figure this out. I think an east coast strike is highly likely at this point given the GFS/Euro and their ensembles overwhelmingly overlapping in the general upper level steering features.