Cat 4 Hurricane Helene | 140mph 938mb | Landfall Big Bend/Perry

[Poco]

Huzzah!

[Jpfalcon]

2 minutes ago, Undertakerson2.0 said:

 

👀

Over 12mb in an hour? Am I reading that correctly?

[Burr]

4 minutes ago, Undertakerson2.0 said:

 

👀

942??!

[Undertakerson2.0]

1 minute ago, Jpfalcon said:

Over 12mb in an hour? Am I reading that correctly?

Correct

[Undertakerson2.0]

Just now, Burr said:

942??!

We look at the value drop (or gain) more than the actual values. The ADT is a Sat derived product which may or may not be 1:1 with observed conditions we see from RECON etc. 

[Burr]

Telltale feathering on the IR presentation (north and west) for a strengthening storm.

[StormfanaticInd]

Huge storm!

[Poco]

[Undertakerson2.0]

2 minutes ago, Burr said:

Telltale feathering on the IR presentation (north and west) for a strengthening storm.

Yes,  I speculated with others that it might be trying to stadium

[Poco]

lol @ topic title 

“strengthening a lot” 

[StretchCT]

72 hr precip in the Blue Ridge . NAM 3k got it right. Already reports of 20+ inches.

24 hr precip 16"+ so far last 24hrs.

[StormfanaticInd]

 

[Undertakerson2.0]

Herc out -

Tag teams to Orion

 

[StretchCT]

Last vortex message transmitted at 3:56 had it at 952mb. Ragged eye 35nm wide. Max flight level winds 132mph on the east side. 9C outside the eye, 17C inside the eye. Max surface winds 101mph. 

Spoiler

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 26th day of the month at 19:56Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF98-5308
Storm Name: Helene
Storm Number & Year: 09 in 2024 (flight in the North Atlantic basin)
Mission Number: 16
Observation Number: 33

A. Time of Center Fix: 26th day of the month at 19:32:20Z
B. Center Fix Coordinates: 27.12N 84.93W
B. Center Fix Location: 162 statute miles (261 km) to the WSW (249°) from Tampa, FL, USA.
C. Minimum Height at Standard Level: 2,712m (8,898ft) at 700mb
D. Minimum Sea Level Pressure: 952mb (28.12 inHg)
E. Dropsonde Surface Wind at Center: From 340° at 8kts (From the NNW at 9mph)
F. Eye Character: Ragged
G. Eye Shape & Diameter: Circular with a diameter of 35 nautical miles (40 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 88kts (101.3mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 19 nautical miles (22 statute miles) to the ENE (68°) of center fix at 19:25:30Z
J. Maximum Flight Level Wind Inbound: From 152° at 104kts (From the SSE at 119.7mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 21 nautical miles (24 statute miles) to the ENE (65°) of center fix at 19:24:30Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 75kts (86.3mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 16 nautical miles (18 statute miles) to the N (356°) of center fix at 19:37:30Z
N. Maximum Flight Level Wind Outbound: From 79° at 78kts (From between the ENE and E at 89.8mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 18 nautical miles (21 statute miles) to the N (356°) of center fix at 19:38:00Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 9°C (48°F) at a pressure alt. of 3,044m (9,987ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 17°C (63°F) at a pressure alt. of 3,058m (10,033ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 10°C (50°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 Levels (surface & flight level centers within 5nm of each other): Surface and 700mb
T. Navigational Fix Accuracy: 0.02 nautical miles
T. Meteorological Accuracy: 1 nautical mile

Remarks Section:
 

Maximum Flight Level Wind: 115kts (~ 132.3mph) which was observed 27 nautical miles (31 statute miles) to the E (88°) from the flight level center at 18:05:30Z

Mission 16 vort data - dropped 10mb over 5 hours. 

Sonde data also tells the story.  the 123kts (142mph) winds were at 900mb. The 121kts were at 905mb. 

Edited September 26 by StretchCT

[Undertakerson2.0]

32 minutes ago, Undertakerson2.0 said:

125mph at next update, nearly certain - or I'll eat my hat

Interim update from TWC - now at 125mph

Actually the NHC update at 5

Edited September 26 by Undertakerson2.0

[StretchCT]

5pm Discussion notes: Rapidly intensified, eyewall completely closed, circular and clearing out. Center contracted signficantly and TS force winds expanded. Helene is the upper bound of hurricanes in terms of storm size. It is speeding up, north at 20kts (which will save some at coast, hurt others inland). Has intensified 30kts since sunrise.  Will be near or at Cat 4 at landfall. 

Spoiler

Hurricane Helene Discussion Number  14
NWS National Hurricane Center Miami FL       AL092024
500 PM EDT Thu Sep 26 2024

Helene has rapidly intensified today while nearing landfall in the
Florida Big Bend.  Doppler radar and aircraft data indicate that the
eyewall is now completely closed and the eye has become more
circular and is clearing out.  The aircraft data also indicated 
that the inner core has contracted significantly today while the
tropical-storm-force winds have expanded.  Based on all of the data,
the initial intensity is set at 110 kt.  The latest minimum pressure
based on the aircraft data is around 951 mb. Tropical-storm-force
winds are occurring across portions of west-central and southwestern
Florida, and conditions are expected to deteriorate rapidly in the
hurricane warning area during the next several hours.  It should be
emphasized that Helene is at the upper bound of hurricanes in
terms of storm size and impacts are and will occur well away 
from the center.

The large hurricane is now accelerating north-northeastward, with
the latest initial motion estimated to be 025/20 kt.  This general
motion is expected to continue, taking the core of the major
hurricane to the Florida Big Bend later this evening.  After
landfall, a turn to the north over Georgia is expected late tonight
and early Friday, followed by a slowdown or a complete stall over
the Tennessee Valley late Friday and Saturday when Helene merges
with a mid- to upper-level low.

The hurricane has intensified by 30 kt since sunrise and given the
conducive environmental conditions and contracting inner core, it
seems likely that Helene will be at or very near category 4 strength
when it makes landfall in the Florida Big Bend this evening.
The fast forward speed when Helene moves inland will result in a
far inland penetration of strong winds over parts of the
southeastern United States, including strong gusts over the higher
terrain of the southern Appalachians.  Accordingly, a
higher-than-normal gust factor is indicated in the official forecast
while Helene is inland.

KEY MESSAGES:

1. A catastrophic and deadly storm surge will occur along portions 
of the Florida Big Bend coast, where inundation could reach as high 
as 20 feet above ground level, along with destructive waves.  If 
you live in this area and were told to evacuate by local officials, 
your opportunity to do so is almost over.  There is also a danger 
of life-threatening storm surge along the remainder of the west 
coast of the Florida Peninsula.  

2. Potentially catastrophic hurricane-force winds are expected 
within the eyewall of Helene and will spread inland over portions 
of northern Florida and southern Georgia when Helene makes landfall 
in the Florida Big Bend region this evening.  Persons in these 
areas should be prepared to take shelter in the interior portion of 
a well-built structure and remain sheltered until after hazardous 
conditions pass. You may need to remain sheltered after the storm 
due to downed trees and power lines, as well as flooding, in the 
area.

3. Damaging wind gusts will penetrate well inland over portions of 
Georgia and the Carolinas  tonight, particularly over the higher 
terrain of the southern Appalachians. Residents in these areas 
should be prepared for the possibility of long-duration power 
outages.  If you use a generator after the storm, be sure it is 
placed outside at least 20 feet away from doors, windows, and 
garages to avoid deadly carbon monoxide poisoning.

4. Catastrophic and life-threatening flash and urban flooding, 
including numerous significant landslides, is expected across 
portions of the southern Appalachians through Friday. Considerable 
to locally catastrophic flash and urban flooding is likely for 
northwestern and northern Florida and the Southeast through Friday. 
Widespread significant river flooding and isolated major river 
flooding are likely.


FORECAST POSITIONS AND MAX WINDS

INIT  26/2100Z 27.9N  84.6W  110 KT 125 MPH
 12H  27/0600Z 31.5N  83.7W   90 KT 105 MPH...INLAND
 24H  27/1800Z 35.8N  85.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 36H  28/0600Z 37.0N  86.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
 48H  28/1800Z 37.1N  87.0W   25 KT  30 MPH...POST-TROP/EXTRATROP
 60H  29/0600Z 37.1N  87.3W   20 KT  25 MPH...POST-TROP/EXTRATROP
 72H  29/1800Z...DISSIPATED

$$
Forecaster Cangialosi

 

[StormfanaticInd]

Eye is looking more well defined. This is bad

[StormfanaticInd]

 

[Poco]

 

 

[StretchCT]

Multiple areas of coastal FL flooded already.

 

Edited September 26 by StretchCT

[StretchCT]

Max gusts since midnight - note the Bahamas even got hit by winds in the 40s

Current max gusts

Edited September 26 by StretchCT

[OxfordOh_]

 

[MaineJay]

[MaineJay]

It feels like a clutch engaging with the flywheel. Foot is coming off the pedal.

[StormfanaticInd]