ATL: HELENE - Models

[Flakeys]

Amateur question. Do models use info from other models in their forecast. Does the GFS us Euro info in their runs?

[jlauderdal]

Amateur question. Do models use info from other models in their forecast. Does the GFS us Euro info in their runs?

HAFS uses some of the gfs background data.

[lsuhurricane]

18z ICON running.....easily shoots the Yucatan/Cuba passage and building a head of steam. Looks like a 948mb landfall.

[kevin]

I had meetings today so here's the delayed 12z blend. Way weaker than the previous blends and more similar to yesterday's 18z blend which peaked at 951 mbar due to land interaction. This cycle has similar issues and as such this blend only peaks at 954 mbar as a cat 1. I added the +57 and +63 time stamps as well since landfall varies ever so slightly between models.

HWRF
PEAK: 942 mb @ 57 hrs | 104 kt @ 57 hrs
hr / pressure (mb) / wind (kt)
00 / 999 / 43
06 / 998 / 45
12 / 991 / 41
18 / 985 / 52
24 / 979 / 57
30 / 976 / 54
36 / 968 / 63
42 / 956 / 82 - C1
48 / 947 / 86 - C2
54 / 943 / 103 - C3
57 / 942 / 102 - landfall
60 / 943 / 70
63 / 946 / 66
66 / 955 / 56

HMON
PEAK: 943 mb @ 60 hrs | 99 kt @ 54 hrs
hr / pressure (mb) / wind (kt)
00 / 1002 / 41
06 / 997 / 42
12 / 992 / 44
18 / 984 / 53
24 / 982 / 51
30 / 981 / 51
36 / 976 / 61
42 / 970 / 69 - C1
48 / 960 / 77
54 / 950 / 99 - C3
57 / 945 / 94
60 / 943 / 95 - landfall
63 / 947 / 65
66 / 955 / 49

HAFS-A
PEAK: 969 mb @ 60 hrs | 64 kt @ 60 hrs
hr / pressure (mb) / wind (kt)
00 / 993 / 46
06 / 997 / 43
12 / 996 / 47
18 / 990 / 52
24 / 990 / 45
30 / 989 / 46
36 / 988 / 47
42 / 984 / 57
48 / 980 / 61
54 / 976 / 60
57 / 974 / 60
60 / 969 / 64 - landfall
63 / 973 / 50
66 / 978 / 54

HAFS-B
PEAK: 962 mb @ 60 hrs | 76 kt @ 60 hrs
hr / pressure (mb) / wind (kt)
00 / 998 / 47
06 / 996 / 42
12 / 994 / 53
18 / 985 / 45
24 / 985 / 45
30 / 988 / 45
36 / 987 / 51
42 / 982 / 53
48 / 975 / 59
54 / 973 / 67 - C1
57 / 969 / 64
60 / 962 / 76 - landfall
66 / 963 / 63
72 / 968 / 49

Blend
PEAK: 954 mb @ 60 hrs | 82 kt @ 54 hrs
hr / pressure (mb) / wind (kt)
00 / 998 / 44
06 / 997 / 43
12 / 993 / 46
18 / 986 / 51
24 / 985 / 50
30 / 984 / 49
36 / 980 / 56
42 / 973 / 65 - C1
48 / 966 / 71
54 / 961 / 62
57 / 958 / 80
60 / 954 / 76 - landfall
63 / 957 / 61
66 / 964 / 52

[Steve]

18z ICON running.....easily shoots the Yucatan/Cuba passage and building a head of steam. Looks like a 948mb landfall.

https://i.ibb.co/XZtKSHm/13-km-ICON-Gulf-of-Mexico-MSLP.gif

It’s on an island

[DunedinDave]

ICON looks to make landfall between Cedar Key and Steinhatchee. ICON and GFS still seem to be on the more eastern side of the guidance. We'll see if the GFS holds their track in about 20 minutes.

[derpbynature]

^^ Note the "ICON" in TWC's list is a different ICON and not the German model we run on here all the time.

Wait, what's this other ICON model then? I want to learn more.

[caneman]

18z ICON running.....easily shoots the Yucatan/Cuba passage and building a head of steam. Looks like a 948mb landfall.

https://i.ibb.co/XZtKSHm/13-km-ICON-Gulf-of-Mexico-MSLP.gif

It’s on an island

Looks east just North of Cedar Key. Lower pressure too i believe than last run. Dangerously close to Pinellas beach. Will get a good raking.

[FLLurker32]

18z ICON running.....easily shoots the Yucatan/Cuba passage and building a head of steam. Looks like a 948mb landfall.

https://i.ibb.co/XZtKSHm/13-km-ICON-Gulf-of-Mexico-MSLP.gif

Yikes, right back to hugging cedar key. This will be a long night.

[DunedinDave]

18z ICON running.....easily shoots the Yucatan/Cuba passage and building a head of steam. Looks like a 948mb landfall.

https://i.ibb.co/XZtKSHm/13-km-ICON-Gulf-of-Mexico-MSLP.gif

It’s on an island

Looks east just North of Cedar Key. Lower pressure too i believe than last run. Dangerously close to Pinellas beach. Will get a good raking.

I'm nervous about storm surge here along the Pinellas beaches and in the Bay. I have a bad feeling this storm is on the verge of exploding and when that happens, that pressure is going to plummet. When was the last time a hurricane of this size with a pressure under 930 passed NW of Tampa Bay?

[Steve]

^^ Note the "ICON" in TWC's list is a different ICON and not the German model we run on here all the time.

Wait, what's this other ICON model then? I want to learn more.

Intensity consensus. So here is the most comprehensive list of literally every model you would ever see and what they are on any possible plot I could think of along with what they are. In the case of this ICON (not the German one we run on Tidbits and Pivotal) Tropical Atlantic explains:

ICON - Intensity Consensus (2021 version, consensus of all: DSHP, LGEM, HWFI, CTCI, HMNI) - This is not German DWD ICON model (more)
All Required
Type: Consensus
Timeliness: Early
Parameters forecast: Intensity

Ending in "I" - Interpolated 6 hours

We last reviewed this consensus model in June 2021. The consensus members are based on either an update to the NHC's nhc_techlist.dat file in June 2021 or were valid as of the 2019 NHC model verification report released in 2020.

^^ note there are embedded links within that description if you go to the link below which again is a list of every model that I’ve ever heard of and dozens I haven’t.

https://tropicalatlantic.com/models/mod ... age=models

Edit to note it also lists defunct models like the ETA, GFDL, Nogaps and their derivatives.

[Powellrm]

They aren't useful (maybe barely) for track purposes. They follow the wind/shear and are Trajectory based as opposed to dynamical, consensus or statistical. They're barely better than Clipper in my opinion (probably worse sometimes). TWC has a page on these which references: Some models just follow the winds, and they are collectively known as the TABs (or Trajectory and Beta Models). These three models - shallow, medium and deep - are slightly more useful (than CLIP/XTRAP) because the closer they are together, they indicate that there is less wind shear in the atmosphere. On the contrary, if they are spread out, this is indicative that there is more wind shear and the system will likely stay weak. A weak system should not be monitored using the deep version of the TABs called TABD since those systems do not tap the upper portions of the atmosphere. Here's a link to the their article from 2022, "Hurricane Spaghetti Models: Four Things You Need to Know to Track Storms Like the Pros."

It's pretty educational, short and worth anyone's 5 minutes to read or even a favorites link for future reference.

https://weather.com/science/weather-exp ... -hurricane

Hey Steve thanks for posting this! Great read.

Yeah word. Any non-met should read that so when we post the early and late cycle tracks and intensity tracks there's a reference point to what the specific models are actually useful for.

I agree, absolutely. I grew up in Wilmington NC, and loved tracking these storms since I was a kid. I was a frequent reader for years but didn’t start posting or interacting until recently. I feel familiar with terminology and what to look for, but I still learn things all the time here. Meteorologist was definitely in my brain for career pathways a long time ago. I learn so much by reading here.

[tolakram]

18Z running.

[FLLurker32]

18Z running.

https://i.imgur.com/YVeO24n.png

Initialized pretty close. This will be interesting.

[StPeteMike]

18Z running.

https://i.imgur.com/YVeO24n.png

Initialized pretty close. This will be interesting.

Looks to get still close to Yucatán ( don’t see it but we will see) but also have a stronger right hand turn that puts Helene into Cedar Key.

[tolakram]

Stronger again

[chris_fit]

Stronger again

https://i.imgur.com/EshHjhF.png

East side looks to be so much stronger. One wobble and Tampa in trouble... Ughh... Still too close for comfort.

[tolakram]

GFS still showing organizational issues. GFS is pretty good in this area, is it right?

[CronkPSU]

Not much change in the GFS run, slightly stronger again but same location and timing

[tolakram]