2021 Global Model Runs Discussion (Out thru day 16)

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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2321 Postby Category5Kaiju » Mon Oct 25, 2021 10:07 am

If some of the ensemble runs are to be believed, we may end up going to the auxiliary list after all and seeing a burst of activity in NOVEMBER (not October, contrary to what I was thinking in September!). Interesting to see if the east coast system nabs the name Wanda, because after that, whatever gets going in the WCAR and (possibly) become a threat to land will get an aux list name.
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2322 Postby chaser1 » Mon Oct 25, 2021 10:52 am

The inconsistent behavior of ensemble members along with the goal posts continuously being pushed farther away does not necessarily make me believe that no other Atlantic "named" tropical cyclones will be named. For those who track hurricane season "foot-notes" there's probably still some juicy odd-ball T.S. or sub-tropical genesis yet to occur. In terms of a hurricane season having implication to people and property, I could buy in to a potential slow brewing deep SW Caribbean solution such as what CMC shows way out around 220 hr's (but i'm sure not gonna hang my hat on any one and done CMC model for tropical development). Outside of some late season impact to Central America, it's difficult for me to believe that much "tropical risk factor" actually remains. In that vein, I'd have to agree with a previous post stating something to the effect of "season end" or "season continued" is more a semantical discussion then anything else. I mean, people are free to discuss about Deep Space Quasars and Black Holes as long as they choose but most would likely shrug their shoulders in favor of some 1st quarter score football game on TV.
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2323 Postby Spacecoast » Mon Oct 25, 2021 11:00 am

jconsor wrote:The GEFS genesis plots on Brammer's site are broken for the time being. You can verify that by noting that the EPac Genesis map is also blank.

Thank you, it seems you are correct. I do like Alan's site, but struggle to understand his methodology...

It appears Alan requires a certain number, or % of ensemble members clustered within certain geography in order to qualify as sufficient probability (threshold) for genesis.If only a few members show development, his plot's are blank.

If you have any additional information on his genesis criteria, I would appreciate it.

FSU's methodology is well defined. It uses operational models, & logistic regression calculations requiring several criteria being met:
1. A relative minimum in mean sea level pressure (MSLP) with at least one closed isobar at a 2mb interval.
2. A relative maximum in 850mb relative vorticity which is horizontally displaced less than 2 degrees lat/lon from the MSLP minimum.*
3. A relative maximum in 250-850mb thickness which is horiztonally displaced less than 2 degrees lat/lon from the MSLP minimum.*
4. The maximum wind speed at 925mb at any point less than 5 degrees lat/lon from the MSLP minimum.*

If criteria 1-4 exist for at least 24 consecutive forecast hours in the model cycle, they classify the system as a 'tropical cyclone' .
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2324 Postby aspen » Mon Oct 25, 2021 12:53 pm

12z CMC once again develops the SW Caribbean system, giving it about two days over water before making landfall in Costa Rica. Some northern members on the 12z GEFS still develop it too. Therefore, development is possible if the northern wave axis becomes dominant and it is slow-moving.
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2021 Global Model Runs Discussion (Out thru day 16)

#2325 Postby skyline385 » Mon Oct 25, 2021 1:05 pm

It's kinda hilarious that even in the midst of a La Nina the EPAC keeps churning out strong systems on the models whereas the NATL just keeps getting quieter. Almost nothing on the 12Z GEFS with only a couple of weak rogue members which vary widely between runs.
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2326 Postby Ubuntwo » Tue Oct 26, 2021 4:11 pm

Small uptick on the 12z Euro ensembles with ~35% developing in the SW Caribbean.
Image
And ~45% on the 12z GEFS. Most are brief spinups.
Image
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2327 Postby Teban54 » Tue Oct 26, 2021 4:28 pm

Ubuntwo wrote:Small uptick on the 12z Euro ensembles with ~35% developing in the SW Caribbean.
https://i.imgur.com/6EcX6ie.png
And ~45% on the 12z GEFS. Most are brief spinups.
https://i.imgur.com/YCV6YsR.png

That feels like the story of October 2021 :lol:
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2328 Postby ChrisH-UK » Wed Oct 27, 2021 10:14 am

Looks like the GFS thinks they maybe a Tropical Storm near Capo Verde on Monday. 30 kont winds and nicely stacked at the low, medium and high level.

Image

Image
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2329 Postby SFLcane » Wed Oct 27, 2021 10:48 am

ChrisH-UK wrote:Looks like the GFS thinks they maybe a Tropical Storm near Capo Verde on Monday. 30 kont winds and nicely stacked at the low, medium and high level.

https://i.imgur.com/0RRc4nS.png

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


Um how about no. Recent model guidance has been nothing short of horrendous in particular the GFS.
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2330 Postby skyline385 » Wed Oct 27, 2021 12:37 pm

SFLcane wrote:
ChrisH-UK wrote:Looks like the GFS thinks they maybe a Tropical Storm near Capo Verde on Monday. 30 kont winds and nicely stacked at the low, medium and high level.

https://i.imgur.com/0RRc4nS.png

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


Um how about no. Recent model guidance has been nothing short of horrendous in particular the GFS.

That Nov 1 CV storm has been on the GFS for a while now. It being within 120 hours now gives it a decent chance imo...
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2331 Postby AutoPenalti » Wed Oct 27, 2021 12:41 pm

If it maintains that energy it may develop in the Caribbean.
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Model Runs Cheat Sheet:
GFS (5:30 AM/PM, 11:30 AM/PM)
HWRF, GFDL, UKMET, NAVGEM (6:30-8:00 AM/PM, 12:30-2:00 AM/PM)
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2332 Postby ChrisH-UK » Wed Oct 27, 2021 3:34 pm

SFLcane wrote:
ChrisH-UK wrote:Looks like the GFS thinks they maybe a Tropical Storm near Capo Verde on Monday. 30 kont winds and nicely stacked at the low, medium and high level.

https://i.imgur.com/0RRc4nS.png

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


Um how about no. Recent model guidance has been nothing short of horrendous in particular the GFS.


Other models like the ECWMF, CMC, KMA, ICON show signs of something happening in the area but not as well defined as the GFS, the small size of it might be the reason. The GFS has been having it for the last day or so and it is getting into the time span where models have a better accuracy. It's a area that we will have to keep a eye on.
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2333 Postby Teban54 » Wed Oct 27, 2021 3:39 pm

FYI, an eastern MDR formation in late October and November (even as a TD) has literally never happened in record history.

So while I still think this has a good chance to be a GFS phantom, if it does happen (and chances are going up as the time frame keeps getting closer), it would be absolutely insane. Reminds me of those AOIs in eastern MDR in June and the wave before Elsa that looked like a TD near Cape Verde at one point. If the season ends in exactly the same way it started...
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2334 Postby jconsor » Wed Oct 27, 2021 4:13 pm

Thread on the possible E. Atlantic development below. Would be very unusual climo-wise and has a short window to develop, but the fact that we even have a *potential* system to discuss in the eastern MDR so late is nothing short of remarkable. Likely the lingering Atlantic Nino is playing a role, with ITCZ tugged south of usual, allowing waves to stay over more favorable SSTs/upper level winds than is typical for this time of year.

 https://twitter.com/yconsor/status/1453467474700218369




 https://twitter.com/yconsor/status/1453468629245251589




 https://twitter.com/yconsor/status/1453469544845090822


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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2335 Postby jconsor » Thu Oct 28, 2021 12:39 am

Update on waning (but still possible) chance for SW Caribbean development. I would give development about a 20% chance next 7 days, but if it occurs likely to be brief due to close proximity to land.

 https://twitter.com/yconsor/status/1453597005155082240


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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2336 Postby MHC Tracking » Sat Oct 30, 2021 5:28 am

Interesting signatures on the latest GFS at around the 100-140 hour range. We might see a new WCAR AOI rather soon.
Image
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2337 Postby AlphaToOmega » Sat Oct 30, 2021 1:28 pm

The 06Z and 12Z GFS show vorticity consolidating in the Caribbean. We will have to see if this is a phantom or an actual storm.

Image
Image
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2338 Postby aspen » Sat Oct 30, 2021 1:45 pm

AlphaToOmega wrote:The 06Z and 12Z GFS show vorticity consolidating in the Caribbean. We will have to see if this is a phantom or an actual storm.

https://i.postimg.cc/FR6F6wqY/gfs-z500-vort-watl-25.png
https://i.postimg.cc/W3zbXs9R/gfs-z500-vort-watl-29.png

The 12z ICON and CMC runs also try developing a TC down there, but the ICON does so in 3 days while the CMC does in 4-5, sooner than the GFS.
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2339 Postby Ubuntwo » Sat Oct 30, 2021 1:55 pm

AlphaToOmega wrote:The 06Z and 12Z GFS show vorticity consolidating in the Caribbean. We will have to see if this is a phantom or an actual storm.

https://i.postimg.cc/FR6F6wqY/gfs-z500-vort-watl-25.png
https://i.postimg.cc/W3zbXs9R/gfs-z500-vort-watl-29.png

GFS ensemble support has been moderate for development in the SW Caribbean over at least a week. Euro ensembles have been less enthusiastic w/ ~20% developing.

The timeframe has slipped back as the next tropical wave is now the incipient disturbance (first wave is too low and in a marginal environment).
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Re: 2021 Global Model Runs Discussion (Out thru day 16)

#2340 Postby Spacecoast » Sat Oct 30, 2021 8:33 pm

Latest Genesis forecasts: ECMF ensembles show possible Caribbean genesis of weak system crossing into EPAC
12z GEFS ensembles, and Operationals from FSU) do not....

Image
Image

Image
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