2018 Tropics: Global Model Runs Discussion (Out to day 16)

[Pearl River]

From New Orleans discussion this morning, the Long Range section:

In the latest installment on our continuing saga of where the
extended range GFS tropical cyclone ends up...24 hours ago, a
formidable hurricane near Mobile Bay next Thu; 18 hours ago, a
weaker system near Pensacola, FL; 12 hours ago, an even weaker
system near Apalachicola, FL; 6 hours ago, a tropical storm at Bay
St. Louis, MS along the Katrina track. Now, 00Z GFS shows a weak
tropical storm near Vermilion, LA next Fri night. This feature
will soon fall into the Day 7 forecast window and will have to be
dealt with, but for the time being, will maintain decent rain
chances that an open gulf flow would bear with or without a formal
system moving through the gulf. It remains difficult to reject
this feature as an artifact of the GFS model, given its run-to-run
consistency on cyclogenesis, but the ECMWF continues to show
nothing but Bermuda ridge extension flow pattern through the
entire forecast period. Stay tuned - same bat time, same bat
channel.

[Aric Dunn]

looks like the GFS was right at least with the MJO speed. the Current favorable MJO phase is starting to nose into the western carrib and gulf area......

[underthwx]

(From the Climate Prediction Center)...The deterministic GFS model runs continue to indicate tropical cyclone (TC) development across the northwest Caribbean Sea with a subsequent track north into the eastern Gulf of Mexico, as early as the middle part of next week. Despite good consistency among recent deterministic GFS model runs, these solutions have only minor support from their ensemble members and the deterministic ECMWF model has yet to indicate TC development. TC development is plausible since a robust atmospheric Kelvin Wave is crossing the Western Hemisphere.

[underthwx]

(From the Climate Prediction Center)...Although it is highly uncertain if a TC develops and tracks north across the Gulf of Mexico during mid-June, chances for locally heavy rain are elevated from the Gulf Coast north to the Ohio Valley and eastern Corn Belt from June 15 to 19. This elevated chance is due to a decrease in 500-hpa heights, in response to the building ridge over the northeast Pacific, along with sufficient low-level moisture. Only a slight risk of heavy precipitation is posted on the Week-2 hazards map due to the inherent uncertainty on timing and location with convective rainfall

[Siker]

GFS ensemble support is pretty good. I count 15/20 members with some sort of low in the Gulf on the 06z run.

[LarryWx]

GFS ensemble support is pretty good. I count 15/20 members with some sort of low in the Gulf on the 06z run.

Yeah, I counted 8 sub 1004 mb lows in the GOM at different times that affect the US GOM coast 6/14-17 out of ~20 members. That is much more active than any recent GEFS run. Is this indicative of a true increased risk of genesis or is it a false alarm? In contrast, only 3 of 50 0Z EPS members were sub 1004. The model wars continue. Let's see what the 12Z model consensus shows.

[Aric Dunn]

GFS ensemble support is pretty good. I count 15/20 members with some sort of low in the Gulf on the 06z run.

[img]https://i.imgur.com/hhQATMR.png[/ig]

Yeah, I counted 8 sub 1004 mb lows in the GOM at different times that affect the US GOM coast 6/14-17 out of ~20 members. That is much more active than any recent GEFS run. Is this indicative of a true increased risk of genesis or is it a false alarm? In contrast, only 3 of 50 0Z EPS members were sub 1004. The model wars continue. Let's see what the 12Z model consensus shows.

I think our best bet for the next couple days until the tropical wave and monsoon trough is in place with deep convection, is comparing the initialized GFS and Euro heights with their respective 12 and 24-hour heights. The GFS extension of the ridging is far less than the Euro even though they both seem to initialize relatively similar heights. Another thing is the GFS as of late has been showing the system in the eastern Gulf and off the east coast of florida being more of a presence. this, of course, will lower pressures along the western extent of the ridging. That could play a role in the latter GFS pressure fields being more conducive for development.

[GCANE]

The ULL that usually anchors around 30N 50W looks like it will begin to develop in about 200 hrs.
That usually allows waves to spin up once they get on the SW side of the ULL.
I know its far out but GFS is showing stronger 850mb OW activity in the Carib / Bahamas in about 2 weeks.
Might see something then.

[CyclonicFury]

12z CMC and ICON both show development. CMC is stronger than the 00z and shows a tropical storm making landfall near NOLA. ICON develops a weak TC at the end of the run.

[Dylan]

GFS is SIGNIFICANTLY stronger on this run. 985mb and quickly intensifying as of 168 hours!

[TheStormExpert]

What's the link to the GFS site, Tropical Tidbits isn't loading the 12z GFS.

EDIT: Never mind found it!

12z GFS @ 162hrs.

[crownweather]

What's the link to the GFS site, Tropical Tidbits isn't loading the 12z GFS.

Weather Models.com is pulling in the 12Z GFS guidance just fine.

[tropicwatch]

Another thing is the GFS as of late has been showing the system in the eastern Gulf and off the east coast of florida being more of a presence. this, of course, will lower pressures along the western extent of the ridging. That could play a role in the latter GFS pressure fields being more conducive for development.

No signs of pressure lowering in the panhandle yet. Here in Panama City we are at 1021mb.

[cycloneye]

@TropicalTidbits
Due to something beyond my control, the 12Z GFS is late on my site, but plots are now being made. Apologies.

 https://twitter.com/TropicalTidbits/status/1005128040035356675

[NDG]

If the GFS turns out to be correct it would catch a lot of people by surprise, if the Euro turns out to be correct it will make JB's love for the model even more

[gatorcane]

UKMET with nada:
http://tgftp.nws.noaa.gov/data/raw/wt/wtnt82.egrr..txt

[cycloneye]

Nothing from them so we will continue to stick here posting the runs.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Fri Jun 8 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Pasch

[NDG]

12z CMC in agreement with GFS.

[NDG]

Nothing from them so we will continue to stick here posting the runs.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Fri Jun 8 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Pasch

Not surprised, not until the Euro comes on board will they not mention the possibilities of development in the western Caribbean/southern GOM.

[LarryWx]

Nothing from them so we will continue to stick here posting the runs.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Fri Jun 8 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Pasch

Wow, they put that one out early! A 2 PM TWO put out at 1:07 PM. Didn't they at least want to wait for the 12Z GEFS?