WeathermanLeprechaun
Member
I'm hearing from people SFMR got 186 but I'm waiting on CyclonicWX to show it.
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Hurricane Melissa
- Thread starter Jacob Aden
- Start date
TornadoFan
Member
lake.effect
Member
There was an MIT study that concluded 190mph was the likely physical limit of Atlantic hurricanes with perfect conditions.
In theory, a hurricane could go well above 200mph sustained but that would require much hotter sea surface temperatures, not found in the oceans (currently). Also, the coriolos effect may put a hard cap on wind speed but we've never observed something >200mph
WeathermanLeprechaun
Member
Oh well then, Melissa has got a chance arguably. Right now with the way things are looking, it will aim for it.
N0mz
Member
There been a couple drops with around 180 mph surface, but not enough to actually pin it as 180.
N0mz
Member
Looks like recon is spinning the block. I applaud them for 5 passes through this thing after NOAA tapped.
WeathermanLeprechaun
Member
Yeah, they know how absolutely crucial data is atm so they're improvising and it's completely the right decision. A system like this you can not afford to let data pass by..
majorhurricane1703
Member
I agree, I’m just wondering how in the world Patricia and typhoon Haiyan got to 200 mph. It’s not like the eastern pacific specifically had warmer waters than what Melissa is currently experiencing in the Caribbean. If anything I argue they were very much comparable and the OHC was quite comparable.
Obviously we know the Atlantic has more complex upper level dynamics that explain why a storm has not reached 200 mph winds yet compared to the Pacific, but I still find it interesting nevertheless.
N0mz
Member
If they find another 180 mph surface level drop on this next pass I think they’ll go to 180 at 2pm
In a modified C130 no less.
TornadoFan
Member
C-130's are some of the toughest birds out there
A lot of these discussions are tied to surface winds. Those winds off the deck may also be realized in the mountainous terrain. I think the 211 mph wind speed in Cuba during Hurricane Ike was eventually confirmed as valid.
N0mz
Member
I’ll never miss a chance to dump on the EF scale…
I fed the winds at height numbers to ChatGPT and had it translate to impacts based on altitude in the mountains in Jamaica. Scary to consider.
Code:
Here’s how to turn that into “what happens on Jamaica’s slopes.”
# 1) Quick altitude map (tropical column, rough but useful)
* **930–900 mb ≈ 700–1,100 m** (2.3–3.6k ft) – mid-high inland hills
* **875–850 mb ≈ 1,400–1,700 m** (4.6–5.6k ft) – upper ridges
* **800–775 mb ≈ ~2,000 m** (6.5k ft)
* **750–725 mb ≈ 2,200–2,500 m** (7.2–8.2k ft) – Blue Mountain Peak is 2,256 m (~7,402 ft), ~**750–760 mb**
* **700 mb ≈ ~3,000 m** (9.8k ft) – above any Jamaican terrain
# 2) Converting flight-level winds to what the mountains feel
Rules of thumb for **sustained 10 m winds** (open exposure):
* **925–900 mb → surface over land:** ~70–85% of flight-level
* **850 mb → surface over land:** ~65–80%
* **700–750 mb → surface over land:** ~55–70%
* **Ridge crests/gaps** can **accelerate** (+10–30%) and **convective bursts** can briefly **mix down** stronger gusts than the sustained numbers. Sheltered valleys can be 30–50% weaker.
# 3) Apply that to Jamaica by elevation band (using your maxima by level)
I’ll group by terrain height and give sustained/gusty ranges. Directions matter: with **N→NE→E** flow in your list, **north and northeast-facing slopes and gaps** are the most exposed; lee (south) slopes get downslope/rotor risks.
### Coastal & low inland (0–400 m / 0–1.3k ft)
Closest level analogue: **“surface / 930 mb” 141 kt (162 mph)** is an over-water metric (SFMR-like) and will **drop over land**.
* **Sustained:** ~70–85% → **100–120 kt (115–140 mph)**
* **Gusts:** 1.2–1.35× sustained in eyewall squalls → **120–160 kt (140–185 mph)**
Exposure: north shore (e.g., Port Maria → Annotto Bay → Buff Bay) takes the brunt with N–NE onshore flow.
### Mid-hills (400–1,100 m / 1.3–3.6k ft) ~**900–930 mb**
Use your 896–907 mb peaks (191–210 kt) but reduce for land.
* **Sustained:** 70–85% of 180–200 kt-class flight winds → **125–170 kt (145–195 mph)** on most-exposed ridges/gaps; **100–140 kt (115–160 mph)** more typical open slopes
* **Gusts:** **150–200 kt (175–230 mph)** possible in eyewall bursts on exposed crests; valleys 30–50% lower
### Upper ridges (1,400–1,800 m / 4.6–5.9k ft) ~**850–875 mb**
You have **850–872 mb = 155–175 kt** from NE.
* **Sustained:** 65–80% → **100–140 kt (115–160 mph)** on open crests; **80–115 kt (90–130 mph)** on open slopes
* **Gusts:** **120–170+ kt (140–195+ mph)** in gaps/eyewall squalls
Note: **NE flow** jets through saddles—watch the **Mavis Bank–Newcastle** approaches and gaps toward **Blue Mountain Forest Reserve**.
### Blue Mountain crest (~2,000–2,256 m / 6.5–7.4k ft) ~**750–770 mb**
Nearest line is **764 mb = 154 kt** from **E**, with **705–738 mb = 140–155 kt** from **E–ESE** above.
* **Sustained:** 55–70% → **75–110 kt (85–125 mph)** on the highest exposed crests
* **Gusts:** **100–140 kt (115–160 mph)** in convective bursts and gap acceleration (lee waves/rotors on south slopes are gnarly even with lower means)
# 4) Directional impact (based on your list)
* **930→850 mb:** winds **N → NE**, slamming **north-facing** coast and windward slopes; gap winds funnel SW-ward into interior valleys.
* **~760–700 mb:** veer **E → ESE** aloft; on highest ridges you’ll feel more easterly component, increasing cross-ridge shear and lee rotors on the **south** side of the Blue Mountains.
# 5) Local effects to expect
* **Gap/foehn acceleration:** narrow passes can add **+20–40%** vs nearby slopes.
* **Lee-side rotors:** severe, chaotic gusts on south slopes when flow is NE–E across the crest.
* **Convective mixing:** in the eyewall, strong downdrafts can **momentarily mix down** near-flight winds to crests and even some mid-hills → **extreme gust spikes**.
* **Surface roughness:** urban/forested valleys can cut sustained winds by **30–50%** vs exposed ridges—but gusts still punch.
# 6) A few anchor translations (ballpark)
* **Annotto Bay / Buff Bay (sea level, windward):** sustained **100–120 kt**, gusts **140–160 kt** if eyewall onshore.
* **Mavis Bank (~1,000 m):** sustained **110–150 kt** open slopes, gusts **150–190 kt** on ridges/through saddles in NE jets.
* **Newcastle / Catherine’s Peak (~1,200–1,300 m):** sustained **110–150 kt** exposed, gusts **160–200 kt** in squalls/gaps.
* **Blue Mountain Peak (2,256 m):** sustained **75–110 kt**, gusts **100–140 kt**; lee-side turbulence south of the crest can be severe.
---
**Takeaway:** your recon shows a terrifyingly energetic core. Near-surface coastal sites won’t reach the 900–850 mb flight numbers, but **exposed ridgelines and gaps** can get **Category 4/5-equivalent sustained winds** with **super-major gusts** when the eyewall and convective bursts intersect terrain. North and northeast exposures are the bullseye; south-side hazards are **turbulent rotors and violent downslope gusts** rather than the same mean wind.N0mz
Member
147kt/170mph in the SE eyewall. Gonna be 170 mph in the 2pm advisory.
Drop in the center is supportive of around 906mb.
Drop in the center is supportive of around 906mb.
Last edited:
188mph surface dropsonde. (corrected previous one from 16:16)
Code:
Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)
Corrected: This observation corrected a previous observation.
Transmitted: 27th day of the month at 16:16Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF98-5308
Storm Name: Melissa
Storm Number: 13 (flight in the North Atlantic basin)
Mission Number: 20
Observation Number: 27
Part A...
Date: Near the closest hour of 16Z on the 27th day of the month
Highest Mandatory Level For Which Wind Was Reported: 850mb
Coordinates: 16.4N 78.1W
Location: 141 statute miles (226 km) to the SW (217°) from Kingston, Jamaica.
Marsden Square: 044
Surface and Standard Isobaric Surfaces
Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
1000mb This level does not exist in this area of the storm above the surface level.
927mb (27.38 inHg) Surface (Sea Level) Unavailable 340° (from the NNW) 163 knots (188 mph)
925mb 17m (56 ft) Unavailable Unavailable 345° (from the NNW) 178 knots (205 mph)
850mb 756m (2,480 ft) 20.6°C (69.1°F) 20.5°C (69°F) 45° (from the NE) 181 knots (208 mph)
700mb 2,427m (7,963 ft) Other data not available.
Information About Radiosonde:
- Launch Time: 15:44Z
- About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction.
Remarks Section...
Dropsonde Location: Dropped in eyewall 45° (NE) from the eye center.
Highest altitude where wind was reported:
- Location: 16.42N 78.14W
- Time: 15:44:32Z
Lowest altitude where wind was reported:
- Location: 16.34N 78.29W
- Time: 15:49:01Z
Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 5° (from the N)
- Wind Speed: 174 knots (200 mph)
Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 65° (from the ENE)
- Wind Speed: 125 knots (144 mph)
- Depth of Sounding: From 707mb to 927mb
Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding:
- Lowest 150m: 152 gpm - 2 gpm (499 geo. feet - 7 geo. feet)
- Wind Direction: 350° (from the N)
- Wind Speed: 185 knots (213 mph)
Sounding Software Version: AEV 40001
Part B: Data for Significant Levels...
Significant Temperature And Relative Humidity Levels
Level Air Temperature Dew Point
927mb (Surface) Unavailable
924mb Unavailable
910mb 23.2°C (73.8°F) 23.2°C (74°F)
850mb 20.6°C (69.1°F) 20.5°C (69°F)
729mb 15.6°C (60.1°F) 15.6°C (60°F)
720mb 16.6°C (61.9°F) 13.3°C (56°F)
702mb 15.0°C (59.0°F) 12.8°C (55°F)
Significant Wind Levels
Level Wind Direction Wind Speed
927mb (Surface) 340° (from the NNW) 163 knots (188 mph)
926mb 340° (from the NNW) 164 knots (189 mph)
925mb 345° (from the NNW) 179 knots (206 mph)
922mb 345° (from the NNW) 194 knots (223 mph)
920mb 345° (from the NNW) 197 knots (227 mph)
917mb 345° (from the NNW) 193 knots (222 mph)
914mb 350° (from the N) 176 knots (203 mph)
912mb 0° (from the N) 185 knots (213 mph)
905mb 5° (from the N) 194 knots (223 mph)
890mb 15° (from the NNE) 159 knots (183 mph)
881mb 25° (from the NNE) 182 knots (209 mph)
873mb 25° (from the NNE) 164 knots (189 mph)
868mb 30° (from the NNE) 170 knots (196 mph)
864mb 30° (from the NNE) 166 knots (191 mph)
860mb 35° (from the NE) 170 knots (196 mph)
858mb 40° (from the NE) 183 knots (211 mph)
854mb 45° (from the NE) 177 knots (204 mph)
850mb 45° (from the NE) 181 knots (208 mph)
811mb 85° (from the E) 155 knots (178 mph)
707mb 125° (from the SE) 167 knots (192 mph)
Winds at a particular level are peak winds since a dropsonde only records momentary slices of data at each level as it falls through the atmosphere. These winds are not 1 minute sustained.
The highest wind observed in the "Significant Wind Levels" section is noted in bold.N0mz
Member
Not seeing it on cyclonicwx yet where is this?
Birds in the eyewall.
I use the direct kmz feed in Google Earth.
Code:
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 27th day of the month at 17:06Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF98-5308
Storm Name: Melissa
Storm Number & Year: 13 in 2025 (flight in the North Atlantic basin)
Mission Number: 20
Observation Number: 34
A. Time of Center Fix: 27th day of the month at 16:47:50Z
B. Center Fix Coordinates: 16.39N 78.25W
B. Center Fix Location: 147 statute miles (237 km) to the SW (220°) from Kingston, Jamaica.
C. Minimum Height at Standard Level: 2,325m (7,628ft) at 700mb
D. Minimum Sea Level Pressure: 908mb (26.82 inHg)
E. Dropsonde Surface Wind at Center: From 340° at 21kts (From the NNW at 24mph)
F. Eye Character: Closed
G. Eye Shape & Diameter: Circular with a diameter of 10 nautical miles (12 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 170kts (195.6mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 5 nautical miles to the WNW (290°) of center fix at 16:46:30Z
J. Maximum Flight Level Wind Inbound: From 16° at 152kts (From the NNE at 174.9mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 5 nautical miles to the WNW (290°) of center fix at 16:46:30Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 152kts (174.9mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 5 nautical miles to the ESE (111°) of center fix at 16:50:00Z
N. Maximum Flight Level Wind Outbound: From 207° at 150kts (From the SSW at 172.6mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 6 nautical miles to the ESE (115°) of center fix at 16:50:30Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 10°C (50°F) at a pressure alt. of 3,056m (10,026ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 25°C (77°F) at a pressure alt. of 3,040m (9,974ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 7°C (45°F)
R. Sea Surface Temp (collected at same location as temp inside eye): Not Available
S. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
S. Fix Level: 700mb
T. Navigational Fix Accuracy: 0.02 nautical miles
T. Meteorological Accuracy: 1 nautical mile
Remarks Section - Remarks That Were Decoded...
Maximum Flight Level Wind: 161kts (~ 185.3mph) which was observed 7 nautical miles to the NE (41°) from the flight level center at 15:44:00Z
Remarks Section - Additional Remarks...
BIRDS IN EYEWALL
General Note About Vortex Messages:
- SFMR and flight level winds are usually averaged over a 10 second period. (The National Hurricane Center's advisory wind speeds are the highest expected winds averaged over a 1 minute period.)N0mz
Member
Where can I find that/set that up for myself?