Hurricane Category 4 Hurricane Helene

Heavy rains have started in the Atlanta area and roads are already flooding. Flooding is expected to intensify.
 
The 00z EURO was 958mb just off the coast southwest of Perry, FL at 8pm CDT. The new 12z EURO is 951mb just off the coast southwest of Perry, FL at 9pm CDT. These two cycles are the first of the operational EURO to have pressures this low.
 
Quick side question: I see there’s a HAFS A/B, but what about the HAFS A/B parents? What is different about what they do, and why are they called the “parents?”
 
slenker said:
Quick side question: I see there’s a HAFS A/B, but what about the HAFS A/B parents? What is different about what they do, and why are they called the “parents?”
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I've wondered about that too
 
JPWX said:
I've wondered about that too
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The Parent Models of HAFS A and B:​

  • HAFS A:
    • Parent Model: FV3-GFS: The Finite-Volume Cubed-Sphere (FV3) dynamical core was first developed for NOAA's Global Forecast System (GFS). The FV3 core offers a balance between accuracy and computational efficiency, and its use in hurricane modeling allows for better integration with global weather systems. HAFS A builds on this framework, using the FV3 core for high-resolution, nested storm grids.
    • Key Advantage: By leveraging the global FV3 model, HAFS A is better at forecasting storm track and large-scale interactions with the environment, such as steering currents and the influence of high-pressure systems.
  • HAFS B:
    • Parent Model: HWRF and HMON: HAFS B is based on the HWRF model and incorporates elements from HMON (Hurricanes in a Multi-scale Ocean-coupled Non-hydrostatic model). These legacy models were specifically designed for hurricane forecasting and have been the backbone of NOAA's operational hurricane intensity forecasts.
    • Key Advantage: HAFS B focuses more on storm-scale processes, such as eyewall dynamics and convection, making it more suited for intensity forecasts and capturing rapid intensification. It uses lessons learned from HWRF and HMON, but with enhancements in resolution and physics.
 
That dry slot is being persistent - if y'all are the praying type, I'd say that's a feature to pray for. Otherwise, nothing stopping her now. Core is wrapped, feeder band on the gulf side established, channel filling with moisture to wrap in - she's off to the races.
 
There will be no - I repeat, NO chasers needed to document a 12-18ft storm surge. If you don't have a remote camera or a well elevated SOLID structure to retreat to already mapped out, do not attempt to chase this. You hear me Brett Adair? ;) LOL.

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Blountwolf said:
There will be no - I repeat, NO chasers needed to document a 12-18ft storm surge. If you don't have a remote camera or a well elevated SOLID structure to retreat to already mapped out, do not attempt to chase this. You hear me Brett Adair? ;) LOL.

View attachment 30220
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Make no mistake - unfortunately, some will try.
 
Love these geniuses looking at a radar image saying "got rid of dry air". As if that captures the mid levels of a TC. <eyeroll>. Yes, she's working on it. No, it's not gone yet. Hot tower firing on the northern part of the CoC will help move that process of mixing out the dry air along though.

1727290355752.png
 
Richardjacks said:
when looking at the loop, the biggest thing that stands out to me is how hte CDO is explanding in all quadrants near the center. The dry air is losing the battle.
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Totally agreed - one does not win a dry air fight in a moist GOM.

FYI - you may find College of DuPage's interface better than ssd's. I like it a lot better.
weather.cod.edu

COD NEXLAB: Satellite and Radar

Check out COD Meteorology's Satellite and Radar Data
weather.cod.edu weather.cod.edu
 
Argus said:
Shouldn't this front tilt this storm further east? Or is it going to stall out or be caught up in traffic?
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The "front" is a result of a upper level trough that is transitioning into a cutoff upper level low. There will be some eastward drift as it crosses the gulf, but it is expected to interact with that upper level low in what's known as a Fujiwara effect interaction, pulling it back west over TN and into KY after it goes basically north across GA.
 
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