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

[Dean4Storms]

So far ECMWF doesn't have anything.

There's not a single Ensemble Member of the 12z run of the ECM EPS with anything either out 15 days. Several develop closed Lows over in the EPAC but nothing Carib. or GOM.

[Frank2]

Still, over 2 weeks out means everything can change. The models did not micro-predict the second MD flood on Sunday, but it happened very unexpectedly, so anything can happen...

[TheStormExpert]

So far ECMWF doesn't have anything.

There's not a single Ensemble Member of the 12z run of the ECM EPS with anything either out 15 days. Several develop closed Lows over in the EPAC but nothing Carib. or GOM.

But there wasn’t anything for awhile showing up on the Euro and it’s Ensembles pre-Alberto while the GFS was going crazy hitting every location along the Gulf Coast with a Cat.3 hurricane at least once.

Personally I’m not buying into this as much as I was with pre-Alberto since all signs are pointing to the East Pacific finally waking up so that would favor and a dead and hostile Caribbean and Gulf.

[Tampa Bay Hurricane]

Based on climatology and the persistent showers/disturbances over the WCarib, combined with troughing over the Eastern US, I think we will get one tropical storm in early to mid June that forms in the Caribbean and moves into the gulf- where it goes from there too early to tell.

[Weather150]

18z GFS. 234 hours is still some ways out, and the Euro and its ensembles aren't really showing anything, but its early June and worth a watch nonetheless.

[northjaxpro]

I am hugging the GFS persistence! The model has done well lately with forecasting Alberto two weeks out and it has continually insisted on Beryl forming. and moving out of the NW Caribbean and moving north into the Southern GOM by June 10. GFS continues to do so as we move farther into time.

[TheStormExpert]

It’s hard to ignore the GFS and its ensembles which are consistent in developing Beryl somewhere in the NW Caribbean in 10 days. Meanwhile the Euro and its ensembles say not so fast!

In my opinion there’s probably a less than 50% chance of development reoccurring in the NW Caribbean within the next two weeks. Like I said yesterday the East Pacific should be active which would favor a hostile Western Atlantic.

[Frank P]

The O6Z GFS pretty much shows a repeat of Alberto, basically same landfall location and intensity as Alberto.. gotta give it credit as it continues to show cyclogenesis on every run albeit landfall points go from central TX coast to the FL Pandhandle

[northjaxpro]

Yes indeed Frank, I agree!!

[wxman57]

If you remember, the GFS picked up on Alberto in the extended range (beyond 10 days). However, its initial forecast of development was around the 18th of May, not the 25th. The date slipped back for 4-5 days and settled in on the 24th. At that time (within 10 days), the EC and Canadian picked up on it. Perhaps the GFS is too early with development again? Watch for the development date to slip back to the the third week of June vs. the second, and then see if the other models pick up on it within 10 days. This may occur early next week.

[srainhoutx]

If you remember, the GFS picked up on Alberto in the extended range (beyond 10 days). However, its initial forecast of development was around the 18th of May, not the 25th. The date slipped back for 4-5 days and settled in on the 24th. At that time (within 10 days), the EC and Canadian picked up on it. Perhaps the GFS is too early with development again? Watch for the development date to slip back to the the third week of June vs. the second, and then see if the other models pick up on it within 10 days. This may occur early next week.

That time frame (third/forth week of June) would seem to fit the arrival of a rather potent CCKW moving across the Eastern Pacific toward the Western Atlantic Basin as well.

[USTropics]

Excerpt from Dr. Master's blog, essentially paraphrasing what wxman57 just stated. Worth noting, the GFS has already backed off on development time frame. There were several runs that started on Sunday 5/27 and continued through 5/29 that showed weak development starting June 6th. It has since slowed the progression of the CAG into the NW Caribbean and favored EPAC development, and thus delayed development (similar to Alberto).

The GFS model in recent runs has been predicting what may be a Central American Gyre (CAG)--similar to the one that spawned Subtropical Storm Alberto--to form over Central America as early as June 6, though. About 30% of the 20 members of the 0Z Friday GFS model ensemble predicted that a tropical depression would spin up out of this CAG in the Western Caribbean sometime during the period June 6 – 12, according to a custom forecast product supplied to WU by cfanclimate.com. Back in mid-May, the GFS model did correctly forecast the genesis of Alberto from a CAG seven days in advance, but only after issuing about a week’s worth of false alarm forecasts. So, until the European and/or UKMET model echo the GFS forecast, we should not pay undue attention to its long-range musings.

https://www.wunderground.com/cat6/start-hurricane-season-brings-reduced-activity-forecasts-csu-tsr

[Aric Dunn]

There looks to be some validity with the GFS> the ICON model which seems to do fairly well at long range. is showing the monsoon trough/Gyre also extending into the western carrib at the same time as the GFS.

only out to 180 hours. but the trough starts to take shape well before that

Also the Euro in the 500mb level also shows the monsoon trough into the western carrib at the same time frame with increased vorticity. and we all know how that typically goes... large area of convection monsoon trough western caribb ?? lol

Euro


Euro simulated IR at the same time as GFS starts to develop something.. the thing to take from this is the monsoon trough will be back into the western carrib around the 7th or 9th of june. and typically this type of set up leads to development of some sort.

[TheStormExpert]

Like several have said today, either Western Caribbean tropical development will get delayed some or not happen at all, though I'd probably would be leaning towards it happening later than never. Likely will be delayed thanks to the potential for two back to back tropical cyclones spinning up in the far eastern pacific.

All this will likely mean at this point until more is certain is yet another uptick in tropical moisture across the Western Caribbean and somewhere along the Gulf Coast (hopefully not Florida).

[MississippiWx]

This would be surprising with a downward phase of the MJO across the area. I’m very skeptical of this.

[LarryWx]

If you remember, the GFS picked up on Alberto in the extended range (beyond 10 days). However, its initial forecast of development was around the 18th of May, not the 25th. The date slipped back for 4-5 days and settled in on the 24th. At that time (within 10 days), the EC and Canadian picked up on it. Perhaps the GFS is too early with development again? Watch for the development date to slip back to the the third week of June vs. the second, and then see if the other models pick up on it within 10 days. This may occur early next week.

I remember and have posted something similar. Around 5/10, the GFS (and FV3) had a number of runs with a TS forming in the W Caribbean 5/18-9 and then moving into FL peninsula around 5/24 as a cat 2 to sometimes even borderline cat 3. Can those even be considered the same entity as Alberto? Also, keep in mind that the favorable MJO that was cited by JB and others in May is not there this time. JB even said the same and he said to look for the GFS W Car storms this time to turn out to be fake storms.

Bottom line as others have said: wait til we're within 10 days and see if GFS persists and other models join in. On the positive side for development is that we're talking much better climo, mid June vs mid to late May. There have been dozens of W Car geneses in mid June, alone, vs only a handful in mid to late May.

[Aric Dunn]

This would be surprising with a downward phase of the MJO across the area. I’m very skeptical of this.

the forecast I saw for the MJO becomes Neutral starting around the 8th of June leading into a favorable phase in the following two weeks. so MJO should not be an inhibiting factor after about the 12th.

June 9th through the 15th it shifting back t favorable.

[aperson]

I think it's important to note that GFS is currently heavily biased toward generating false positives at long range forecasts.

 https://twitter.com/mattlanza/status/1002257548991500293

[Aric Dunn]

I think it's important to note that GFS is currently heavily biased toward generating false positives at long range forecasts.

 https://twitter.com/mattlanza/status/1002257548991500293

umm thats fine and dandy but does not say anything about the GFS being biased.. Because there was actually a TC threatening the US for many of those 24 ( or 39%) 12z & 00z runs.

now if alberto never formed then that statistic is more relevant.

[LarryWx]

# of W Caribbean/GOM geneses on record 1851-2017: mid-June climo much more active vs May and most active of any through 8/31

May 1-10: 2
May 11-20: 4
May 21-31: 5
June 1-10: 16
June 11-20: 26
June 21-30: 25
July 1-10: 13
July 11-20: 8
July 21-31: 18
Aug 1-10: 23
Aug 11-20: 25
Aug 21-31: 22

So, in mid June, alone, there have been 26 geneses in 167 years or one every 6-7 years averaged out in a fairly small area/over 5 times the rate of late May. That's a steep enough ramp up and high enough ratio to take seriously if there were to be model consensus for genesis there once we get within 10 days. But we're obviously not to that point yet.