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

[Undertakerson2.0]

6z suite continues with the deeper intensities

 

[MaineJay]

Pretty good circulation on TPW.

[Undertakerson2.0]

The erstwhile Helene is looking much more put together in recent IR scans. 

That it is doing this in the face of some rather stout Deep SHR is quite impressive to me. Once the Yuca trough retrogrades West today, the SHR is forecast to relax and E. Helene very well ought to respond accordingly and make for some impressive structural changes. 

It's building convection on the W and S sides now. 

I speculate it will be named at or prior to the 11:00 a.m. (EST) update

I a

[Undertakerson2.0]

Not named at 8 a.m. update. We'll see if 11 a.m. pulls the lever. 

Toggle these images (3 hrs +/-) to see the relaxation of the SW shear already underway - as well as the flexing of the Ridge to the "top right". This will not only serve to increase the intensity of helene, it will also steer it nearly directly mid channel of the Yucatan. 

https://tropic.ssec.wisc.edu/real-time/dlmmain.php?&basin=atlantic&sat=wg8&prod=dlm1&zoom=&time=

[Undertakerson2.0]

Looking at RECON output, tropical storm level winds are being encountered - I believe it's Mission 4 picking them up in the NE Q?

 

[StretchCT]

Looking at the first run (of a consistent run) of models with the track going into Panhandle/BigBend.  0z/12z

ECMWF = 9/22 0z - started hitting just west of FL

AIFS = 9/19 12z.  It had earlier runs hitting FL, but lost it on the 0z runs on the 18th and 19th. 

GFS = 9/17 12z (furthest I could go back) they all hit FL

CMC = 9/17 12z (furthest I could go back)  all but one run hit FL

ICON = 9/20 12z (only goes out 180) prior runs had TX and LA

 

[Undertakerson2.0]

6 minutes ago, StretchCT said:

Looking at the first run (of a consistent run) of models with the track going into Panhandle/BigBend.  0z/12z

ECMWF = 9/22 0z - started hitting just west of FL

AIFS = 9/19 12z.  It had earlier runs hitting FL, but lost it on the 0z runs on the 18th and 19th. 

GFS = 9/17 12z (furthest I could go back) they all hit FL

CMC = 9/17 12z (furthest I could go back)  all but one run hit FL

ICON = 9/20 12z (only goes out 180) prior runs had TX and LA

 

My post on the Central PA Skywarn page on FB - 6 days ago...

[StretchCT]

Saw a Tik Tok by a met who made an excellent point that without NOAA/NHC and without models, we probably wouldn't know a storm was coming. She posted it yesterday, but even now, you'd suspect something on the satellite, and it's almost there, but would you know it would hit FL in 60-72 hrs?

Here's the satellite.  It looks to me that the shear has calmed down compared to yesterday as the cloud tops aren't wildly blowing off anymore, except over Cuba. But the rest of the area looks pretty decent and I'd expect those tops to blow off that direction anyway. The coc is on the edge of the convection and there's a band attached to it on the south side. Outflow is starting to look good too. 

 

[StretchCT]

Cuba radar

http://www.insmet.cu/asp/genesis.asp?TB0=PLANTILLAS&TB1=RADAR&TB2=../Radar/00Pinar del Rio/lbjMAXw01a.gif

Cayman radar

https://www.weather.gov.ky/

hdobs from mission 5, flying at 925mb or around 2500 feet. 

 

 

[StretchCT]

Intensity trends

[Jon Snow]

30 minutes ago, StretchCT said:

Saw a Tik Tok by a met who made an excellent point that without NOAA/NHC and without models, we probably wouldn't know a storm was coming. She posted it yesterday, but even now, you'd suspect something on the satellite, and it's almost there, but would you know it would hit FL in 60-72 hrs?

Here's the satellite.  It looks to me that the shear has calmed down compared to yesterday as the cloud tops aren't wildly blowing off anymore, except over Cuba. But the rest of the area looks pretty decent and I'd expect those tops to blow off that direction anyway. The coc is on the edge of the convection and there's a band attached to it on the south side. Outflow is starting to look good too. 

 

That is something I often think about with these storms.  Given current technology the true surprises we get are minimal, but wow, 100 years ago, folks are busy with their everyday routine and then get slammed with something like this potential storm out of the blue.  We can not change what is coming now, but we can prepare, and that can make all the difference, but back in the day, how much scarier was that. 

[Undertakerson2.0]

5 minutes ago, Jon Snow said:

That is something I often think about with these storms.  Given current technology the true surprises we get are minimal, but wow, 100 years ago, folks are busy with their everyday routine and then get slammed with something like this potential storm out of the blue.  We can not change what is coming now, but we can prepare, and that can make all the difference, but back in the day, how much scarier was that. 

Isaac's Storm - recounts the disaster of the Great Galveston Hurricane. Recommended reading about meteorology in its infancy AND a case study in hubris leading to disasterous results. 

[Undertakerson2.0]

TWC anticipates Helene being born at 11 update  I concur

[StretchCT]

Very little chance there are hurricane winds from this one.👀

Better chances for a 50kt wind

I hate these maps. I think they are misleading. This is what they are derived from.

[Jon Snow]

8 minutes ago, Undertakerson2.0 said:

Isaac's Storm - recounts the disaster of the Great Galveston Hurricane. Recommended reading about meteorology in its infancy AND a case study in hubris leading to disasterous results. 

I just downloaded that on audible, will listen to it on the way to Edisto Island, SC this Sunday.  That is, assuming Helene does not alter course and do head to the east coast. 

[StretchCT]

This buoy is in the path of the storm

https://www.ndbc.noaa.gov/station_page.php?station=42056

[Undertakerson2.0]

15 minutes ago, Undertakerson2.0 said:

TWC anticipates Helene being born at 11 update  I concur

Annnnd there its is

 

Welcome Helene

 

Now shoo - git - gwon GIT!! 

 

[Undertakerson2.0]

 

[StretchCT]

Gonna be a big one per discussion. Other notes:  well defined center, tight cluster of tracks, shear is decreasing, high oceanic heat content and upper level divergence going to make this a major hurricane. It is also predicted to be in the 90th percentile for size which will shield it from shear later on as it approaches land, will cause more widespread damage than usual and increase the surge.  It will be hustling as it makes landfall making it possible that hurricane conditions last further inland than usual.  

Spoiler

Tropical Storm Helene Discussion Number   5
NWS National Hurricane Center Miami FL       AL092024
1100 AM EDT Tue Sep 24 2024

An Air Force Reserve Hurricane Hunter measured peak 925-mb
flight-level winds of 52 kt to the northeast of the center, which
supports an initial intensity of 40 kt.  Dropsonde data also
indicated that the central pressure is down to 1000 mb. Very 
recently, data from the plane and one-minute visible satellite 
imagery indicate that the center has become better defined. Based 
on these data, the system is being designated as Tropical Storm 
Helene at this time.

Helene is moving a little faster toward the northwest (310/10 kt) 
as it moves around a mid-level area of high pressure located over 
Florida and the Southeastern U.S.  The high is expected to slide 
eastward through Wednesday as a deep-layer trough digs southward 
over the Lower Mississippi Valley.  This pattern evolution should 
cause the system to turn northward and north-northeastward late 
Wednesday into Thursday.  The track guidance is very tightly 
clustered, which would normally imply high forecast confidence.  
However, depending on exactly where the center forms could end up 
shifting the entire guidance suite in future cycles, so it is 
imperative to not focus on specific landfall locations this far in 
the future.

Satellite trends suggest that the shear over the system is
beginning to decrease, and model guidance continues to show
relatively low to moderate shear for the next 48 hours or so.  In
addition, oceanic heat content values are very high, and the system
will be moving through an environment of upper-level divergence.
Therefore, significant strengthening is anticipated, and the NHC
intensity forecast shows the system reaching a peak intensity
around 100 kt in 48 hours while over the eastern Gulf of Mexico.
There could be some increase in shear around the time the system
reaches the coast, given the system's large size, it might only
weaken slowly.  As a result, there is still a risk that the system
could reach the coast as a major hurricane.

Helene's forecast radii are at the 90th percentile of hurricane
size at similar latitudes.  Due to the forecast large size of this
system, storm surge, wind, and rainfall impacts will extend well
away from the center, particularly on the east side.  In addition,
the fast forward speed while it crosses the coast will likely result
in farther inland penetration of strong winds over parts of the
southeastern United States after landfall.


KEY MESSAGES:

1. Helene is forecast to intensify and be near hurricane strength 
when it reaches the far northwestern Caribbean Sea early Wednesday. 
Tropical storm conditions are expected over portions of western 
Cuba and the northeastern coast of the Yucatan Peninsula with 
hurricane conditions possible.

2. Helene is expected to rapidly intensify over the eastern
Gulf of Mexico and be a major hurricane when it approaches the
northeastern Gulf Coast on Thursday.  The risk of impacts from
life-threatening storm surge and damaging hurricane-force winds
continues to increase along the coast of the Florida Panhandle and
the Florida west coast.  Hurricane and Storm Surge Watches are in
effect for much of that area and residents in those areas should
follow advice given by local officials.

3. Helene will bring heavy rain to portions of the western 
Caribbean, which will cause considerable flooding and mudslides 
across western Cuba.  Heavy rainfall will likely result in locally 
considerable flash and urban flooding across portions of Florida, 
with isolated flash and urban flooding possible across the 
Southeast, Southern Appalachians, and the Tennessee Valley 
Wednesday through Friday. Minor to isolated moderate river flooding 
will be possible.


FORECAST POSITIONS AND MAX WINDS

INIT  24/1500Z 19.5N  84.3W   40 KT  45 MPH
 12H  25/0000Z 20.3N  85.2W   50 KT  60 MPH
 24H  25/1200Z 21.5N  86.3W   65 KT  75 MPH
 36H  26/0000Z 23.2N  86.3W   80 KT  90 MPH
 48H  26/1200Z 25.9N  85.4W  100 KT 115 MPH
 60H  27/0000Z 29.7N  84.3W  100 KT 115 MPH
 72H  27/1200Z 33.9N  83.9W   45 KT  50 MPH...INLAND
 96H  28/1200Z 39.7N  86.8W   20 KT  25 MPH...POST-TROPICAL
120H  29/1200Z...DISSIPATED

$$
Forecaster Berg

FORECAST POSITIONS AND MAX WINDS

INIT  24/1500Z 19.5N  84.3W   40 KT  45 MPH
 12H  25/0000Z 20.3N  85.2W   50 KT  60 MPH
 24H  25/1200Z 21.5N  86.3W   65 KT  75 MPH
 36H  26/0000Z 23.2N  86.3W   80 KT  90 MPH
 48H  26/1200Z 25.9N  85.4W  100 KT 115 MPH
 60H  27/0000Z 29.7N  84.3W  100 KT 115 MPH
 72H  27/1200Z 33.9N  83.9W   45 KT  50 MPH...INLAND
 96H  28/1200Z 39.7N  86.8W   20 KT  25 MPH...POST-TROPICAL
120H  29/1200Z...DISSIPATED

[FortySixAnd32]

1 hour ago, StretchCT said:

Gonna be a big one per discussion. Other notes:  well defined center, tight cluster of tracks, shear is decreasing, high oceanic heat content and upper level divergence going to make this a major hurricane. It is also predicted to be in the 90th percentile for size which will shield it from shear later on as it approaches land, will cause more widespread damage than usual and increase the surge.  It will be hustling as it makes landfall making it possible that hurricane conditions last further inland than usual.  

  Reveal hidden contents

Tropical Storm Helene Discussion Number   5
NWS National Hurricane Center Miami FL       AL092024
1100 AM EDT Tue Sep 24 2024

An Air Force Reserve Hurricane Hunter measured peak 925-mb
flight-level winds of 52 kt to the northeast of the center, which
supports an initial intensity of 40 kt.  Dropsonde data also
indicated that the central pressure is down to 1000 mb. Very 
recently, data from the plane and one-minute visible satellite 
imagery indicate that the center has become better defined. Based 
on these data, the system is being designated as Tropical Storm 
Helene at this time.

Helene is moving a little faster toward the northwest (310/10 kt) 
as it moves around a mid-level area of high pressure located over 
Florida and the Southeastern U.S.  The high is expected to slide 
eastward through Wednesday as a deep-layer trough digs southward 
over the Lower Mississippi Valley.  This pattern evolution should 
cause the system to turn northward and north-northeastward late 
Wednesday into Thursday.  The track guidance is very tightly 
clustered, which would normally imply high forecast confidence.  
However, depending on exactly where the center forms could end up 
shifting the entire guidance suite in future cycles, so it is 
imperative to not focus on specific landfall locations this far in 
the future.

Satellite trends suggest that the shear over the system is
beginning to decrease, and model guidance continues to show
relatively low to moderate shear for the next 48 hours or so.  In
addition, oceanic heat content values are very high, and the system
will be moving through an environment of upper-level divergence.
Therefore, significant strengthening is anticipated, and the NHC
intensity forecast shows the system reaching a peak intensity
around 100 kt in 48 hours while over the eastern Gulf of Mexico.
There could be some increase in shear around the time the system
reaches the coast, given the system's large size, it might only
weaken slowly.  As a result, there is still a risk that the system
could reach the coast as a major hurricane.

Helene's forecast radii are at the 90th percentile of hurricane
size at similar latitudes.  Due to the forecast large size of this
system, storm surge, wind, and rainfall impacts will extend well
away from the center, particularly on the east side.  In addition,
the fast forward speed while it crosses the coast will likely result
in farther inland penetration of strong winds over parts of the
southeastern United States after landfall.


KEY MESSAGES:

1. Helene is forecast to intensify and be near hurricane strength 
when it reaches the far northwestern Caribbean Sea early Wednesday. 
Tropical storm conditions are expected over portions of western 
Cuba and the northeastern coast of the Yucatan Peninsula with 
hurricane conditions possible.

2. Helene is expected to rapidly intensify over the eastern
Gulf of Mexico and be a major hurricane when it approaches the
northeastern Gulf Coast on Thursday.  The risk of impacts from
life-threatening storm surge and damaging hurricane-force winds
continues to increase along the coast of the Florida Panhandle and
the Florida west coast.  Hurricane and Storm Surge Watches are in
effect for much of that area and residents in those areas should
follow advice given by local officials.

3. Helene will bring heavy rain to portions of the western 
Caribbean, which will cause considerable flooding and mudslides 
across western Cuba.  Heavy rainfall will likely result in locally 
considerable flash and urban flooding across portions of Florida, 
with isolated flash and urban flooding possible across the 
Southeast, Southern Appalachians, and the Tennessee Valley 
Wednesday through Friday. Minor to isolated moderate river flooding 
will be possible.


FORECAST POSITIONS AND MAX WINDS

INIT  24/1500Z 19.5N  84.3W   40 KT  45 MPH
 12H  25/0000Z 20.3N  85.2W   50 KT  60 MPH
 24H  25/1200Z 21.5N  86.3W   65 KT  75 MPH
 36H  26/0000Z 23.2N  86.3W   80 KT  90 MPH
 48H  26/1200Z 25.9N  85.4W  100 KT 115 MPH
 60H  27/0000Z 29.7N  84.3W  100 KT 115 MPH
 72H  27/1200Z 33.9N  83.9W   45 KT  50 MPH...INLAND
 96H  28/1200Z 39.7N  86.8W   20 KT  25 MPH...POST-TROPICAL
120H  29/1200Z...DISSIPATED

$$
Forecaster Berg

FORECAST POSITIONS AND MAX WINDS

INIT  24/1500Z 19.5N  84.3W   40 KT  45 MPH
 12H  25/0000Z 20.3N  85.2W   50 KT  60 MPH
 24H  25/1200Z 21.5N  86.3W   65 KT  75 MPH
 36H  26/0000Z 23.2N  86.3W   80 KT  90 MPH
 48H  26/1200Z 25.9N  85.4W  100 KT 115 MPH
 60H  27/0000Z 29.7N  84.3W  100 KT 115 MPH
 72H  27/1200Z 33.9N  83.9W   45 KT  50 MPH...INLAND
 96H  28/1200Z 39.7N  86.8W   20 KT  25 MPH...POST-TROPICAL
120H  29/1200Z...DISSIPATED

Sounds like a recipe for disaster....

[Psu1313]

1 minute ago, FortySixAnd32 said:

Sounds like a recipe for disaster....

Hoping that forward speed and some shear being introduced as we get near the coast line limits the landfalling storm, but I think we're all expecting something impressive tomorrow. 

[Undertakerson2.0]

12 minutes ago, Psu1313 said:

Hoping that forward speed and some shear being introduced as we get near the coast line limits the landfalling storm, but I think we're all expecting something impressive tomorrow. 

LOVE that we can, now, open the CIMSS Tools to get even more real time information on Helene 

[StretchCT]

HAFS A&B have Helene not organizing very well and take it over the Yucatan before launching into the GOM resulting in a much reduced storm. 

[Hoosier]

3 minutes ago, StretchCT said:

HAFS A&B have Helene not organizing very well and take it over the Yucatan before launching into the GOM resulting in a much reduced storm. 

That potential Yucatan encounter is certainly something to watch.  Only 3 or 4 hours over land could make a big difference compared to like 12 hours.

[Undertakerson2.0]

 

The gate has been swung wide open now - only a touch of SHR on the Cuba side of the Yuca Straits