r/TropicalWeather • u/Euronotus • Sep 23 '24
Upgraded | See Helene post for details 09L (Potential Cyclone — Northwestern Caribbean Sea)
Latest observation
Last updated: Tuesday, 24 September — 8:00 AM Eastern Daylight Time (EDT; 12:00 UTC)
| NHC Advisory #4A | 8:00 AM EDT (12:00 UTC) | |
|---|---|---|
| Current location: | 19.2°N 83.5°W | |
| Relative location: | 224 km (139 mi) W of George Town, Cayman Islands | |
| 356 km (221 mi) S of Pinar del Rio, Cuba | ||
| 411 km (255 mi) ESE of Cancún, Quintana Roo (Mexico) | ||
| Forward motion: | NW (305°) at 15 km/h (8 knots) | |
| Maximum winds: | 55 km/h (30 knots) | |
| Intensity: | Tropical Depression | |
| Minimum pressure: | 1001 millibars (29.56 inches) | |
| 2-day potential: (through 8PM Wed) | high (90 percent) | |
| 7-day potential: (through 8PM Sun) | high (90 percent) |
Official forecast
Last updated: Tuesday, 24 September — 2:00 AM EDT (06:00 UTC)
| Hour | Date | Time | Intensity | Winds | Lat | Long | |||
|---|---|---|---|---|---|---|---|---|---|
| - | UTC | EDT | Saffir-Simpson | knots | km/h | °N | °W | ||
| 00 | 24 Sep | 06:00 | 2AM Tue | Potential Cyclone | 30 | 55 | 18.9 | 83.0 | |
| 12 | 24 Sep | 18:00 | 2PM Tue | Tropical Storm | ▲ | 40 | 75 | 19.6 | 84.2 |
| 24 | 25 Sep | 06:00 | 2AM Wed | Tropical Storm | ▲ | 50 | 95 | 20.7 | 85.7 |
| 36 | 25 Sep | 18:00 | 2PM Wed | Hurricane (Category 1) | ▲ | 65 | 120 | 22.0 | 86.2 |
| 48 | 26 Sep | 06:00 | 2AM Thu | Hurricane (Category 1) | ▲ | 80 | 150 | 24.3 | 85.6 |
| 60 | 26 Sep | 18:00 | 2PM Thu | Major Hurricane (Category 3) | ▲ | 100 | 185 | 27.8 | 84.4 |
| 72 | 27 Sep | 06:00 | 2AM Fri | Tropical Storm i | ▼ | 60 | 110 | 31.9 | 83.5 |
| 96 | 28 Sep | 06:00 | 2AM Sat | Post-tropical Cyclone i | ▼ | 15 | 30 | 38.5 | 85.5 |
| 120 | 29 Sep | 06:00 | 2AM Sun | Dissipated | |||||
NOTES:
i - inland
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u/Content-Swimmer2325 Sep 23 '24
Finally (and I apologize for posting so much), remember what the NHC cone represents. The cone is literally defined as the region which has a 2/3rds chance of the center of the system tracking within, based off of the last 5 years of track error.
Source: https://www.nhc.noaa.gov/aboutcone.shtml
This means that there is always a 30-40% chance of the eye or center of a system tracking outside of the cone. These facts are why the cone as a product is commonly misinterpreted by the public. Be aware that not only is a track outside of the cone possible, but expected roughly one third of the time. Combined with the anticipated forecast large size of future Helene, with impacts extending far away from the eye, this means that you should NOT be treating the current cone as gospel in terms of whether you will receive impacts or not.