2017 Global Model Runs Discussion (Out to day 16)

[joey]

Folks,
The 00Z GFS has a weak surface low form along a stationary front over Sofla on Friday. Then it moves on Saturday NE to ~100 miles E of Melbourne, where it stalls. Then it moves back SW to Sofla on Sunday followed by a westward move into the Gulf on Monday. It remains weak the entire time.
The CMC (take with a huge grain) has a low form just n of W Cuba on Friday followed by a move NE to just off SW FL, where it stalls and becomes a TC on Saturday. Then on Sunday it moves westward out into the Gulf as a TS and reaches N MX late on Tuesday.

all those moves just made me dizzy lol how strong could this one get thanks

[LarryWx]

Folks,
The 00Z GFS has a weak surface low form along a stationary front over Sofla on Friday. Then it moves on Saturday NE to ~100 miles E of Melbourne, where it stalls. Then it moves back SW to Sofla on Sunday followed by a westward move into the Gulf on Monday. It remains weak the entire time.
The CMC (take with a huge grain) has a low form just n of W Cuba on Friday followed by a move NE to just off SW FL, where it stalls and becomes a TC on Saturday. Then on Sunday it moves westward out into the Gulf as a TS and reaches N MX late on Tuesday.

all those moves just made me dizzy lol how strong could this one get thanks

Well, either track has it moving over very warm water. So, from that standpoint, alone, it could in theory get pretty strong (to a H) if it also had very favorable atmospheric conditions . However, very favorable atmospheric conditions aren't expected at this time. Nevertheless, that could change since this is an evolving situation. So, I advise that this area be monitored. It is not all that unusual for a TC or STC to form off FL/SE US coast to the south of a big surface high in very late Sep. (9/25+) or early Oct. when there isn't El Nino. Last ones to form 9/25-10/10: Tammy of 2005, Leslie of 2000, Marco of 1990, Isidore of 1984, STS #18 in 1974, Greta of 1970, TS #7 of 1947, storm # 9 of 1937, storm #4 of 1919, storm #12 of 1916, storm #12 of 1887, H #10 of 1869, and TS #7 of 1866...none of these was during El Nino. So, about once every 10 years on average and during non-Nino seasons.

Edit: The 0Z GEFS mean also has this weak low.

Anyone staying up for the Euro?

Edit: Indeed, the 0Z Euro has two microcyclones that hit FL from the ENE that exist during 9/30-10/4.

[chaser1]

If I'm not mistaken the new EURO appears to develop a W. Caribbean monsoonal low in the 7-10 day time frame, just as the GFS began doing in its prior very long range. Looks to be a far greater rainfall producer than wind threat right now

[ronjon]

Looks like we'll need to start a separate thread with possible low pressure developing east of Florida this weekend. From Melbourne AFD:

Thursday-Saturday...Mid-upper level trough/weak cutoff low extending
from the NE GOMEX into south GA will drift slowly south-SSW through
the period. This will place the Florida peninsula into its ascending
eastern flank, with the position of the S/SSW H25 jetstreak keeping
the flow aloft quite divergent overhead and to our east through
Friday, before weakening some Saturday. Global model guidance shows
lowering surface pressures in response to the upper forcing, with an
inverted trough, and possibly a weak surface low, developing over
the northern Bahamas beginning Friday afternoon, which drifts NE on
Saturday, possibly stalling east of Florida by late Saturday night.
This lowering of pressures will combine with a strong early fall
surface ridge building over the deep south to tighten the local
surface pressure gradient.

In addition to freshening winds, a steady increase in mean layer
moisture/convergence is progged, especially by Saturday, which will
result in coverage of showers becoming numerous to widespread, while
increasing clouds/winds hold down max temps and limit coverage of
thunderstorms. The inherited forecast already showed this trend, and
the only changes were to nudge both POPs and clouds up a bit through
the period. south to north increase from 20 north/50 south Friday-
Friday night to 50 north/inland to 70 coast/south Saturday-Saturday
night. Maxes in the L90s areawide will drop back to 88-91F Friday
and M-U80s Saturday. Mins in the L-M70s inland, increasing to U70s
along the coast Saturday night.

By Saturday, there will be an increasing concern for local hazardous
impacts from heavy rainfall, especially in training bands along
coastal areas. Given the ongoing larger basin river flood concerns
coupled with the high water table, residents in areas with ongoing
flooding or that are prone to re-flood, may need to take additional
measures to protect property from additional inundation.

Sunday-Tuesday...A strong mid level ridge will build over the
central and eastern CONUS, keeping a large and strong surface high
in place to our north. Not only will this keep stout and very moist
onshore low level flow in place, but NE to ENE flow aloft will
effectively trap whatever low or trough forms to our east and shove
it back westward over the state by Sunday (GFS) or Monday (ECMWF).
Regardless, above normal rain chances and breezy to windy conditions
will prevail into early next with the potential for locally heavy
rainfall continuing through at least Monday. Max temps will remain
a few degrees below normal while mins run several degree above due
to a continued moderate to fresh onshore breeze.

[northjaxpro]

Well, besides this Global Models Thread we have been using to discuss this potential near Florida, I have been posting in the Florida Weather thread about the possible development east of Cape Canaveral this weekend but I'm sure the moderators will probably all start a new thread on this potential Low development with the model support that we have now probably later today

[SFLcane]

Nothing on these models screams a strong hurricane as of now hopefully a sloppy wet system.

[LarryWx]

Nothing on these models screams a strong hurricane as of now hopefully a sloppy wet system.

Yeah, the odds would be against a H, period, (despite the very warm SSTs in/near the Bahamas) so close in without great atmospheric conditions based on history (though far from impossible, of course), but even just a TS/STS or even a TD/STD would be of major interest as the last thing FL/se GA would want right now after Irma's deluges/coastal flooding is more heavy rain. Also, just a TS/STS or even a TD/STD could help induce coastal flooding to its north in early Oct. due to the pinching of the gradient in concert with the progged strong NE US surface high as the full moon approaches.

Edit: the 0Z EPS has one member with a 1004 low just E of Daytona on 10/1. It also has one member that is sub 1000 mb (TS?) about 125 miles E of Brunswick late on 10/3 moving westward into GA on 10/4.

[TheStormExpert]

Nothing on these models screams a strong hurricane as of now hopefully a sloppy wet system.

Yeah, the odds would be against a H, period, (despite the very warm SSTs in/near the Bahamas) so close in without great atmospheric conditions based on history (though far from impossible, of course), but even just a TS/STS or even a TD/STD would be of major interest as the last thing FL/se GA would want right now after Irma's deluges/coastal flooding is more heavy rain. Also, just a TS/STS or even a TD/STD could help induce coastal flooding to its north in early Oct. due to the pinching of the gradient in concert with the progged strong NE US surface high as the full moon approaches.

So why would odds be against a powerful hurricane in the Western Caribbean in October?

We have a quickly developing La Niña, warm SST’s, untouched TCHP, light wind shear being hinted, and vertical instability.

Unless due to the fact that it may be lifting north into the Gulf quickly I see no reason to discount chances of a powerful hurricane in the Western Caribbean next month.

In fact models may just be now honing in on the early indications of something down there rather than a system itself in early October as you usually don’t see something coming out of the Western Caribbean until the 2nd or 3rd week in October similar to Irene (1999), or Wilma (2005).

[LarryWx]

Nothing on these models screams a strong hurricane as of now hopefully a sloppy wet system.

Yeah, the odds would be against a H, period, (despite the very warm SSTs in/near the Bahamas) so close in without great atmospheric conditions based on history (though far from impossible, of course), but even just a TS/STS or even a TD/STD would be of major interest as the last thing FL/se GA would want right now after Irma's deluges/coastal flooding is more heavy rain. Also, just a TS/STS or even a TD/STD could help induce coastal flooding to its north in early Oct. due to the pinching of the gradient in concert with the progged strong NE US surface high as the full moon approaches.

So why would odds be against a powerful hurricane in the Western Caribbean in October?

We have a quickly developing La Niña, warm SST’s, untouched TCHP, light wind shear being hinted, and vertical instability.

Unless due to the fact that it may be lifting north into the Gulf quickly I see no reason to discount chances of a powerful hurricane in the Western Caribbean next month.

In fact models may just be now honing in on the early indications of something down there rather than a system itself in early October as you usually don’t see something coming out of the Western Caribbean until the 2nd or 3rd week in October similar to Irene (1999), or Wilma (2005).

Sorry about the confusion. We're not talking about the W Caribbean system right here now. That now has its own thread. Here we're now dealing with a potential earlier homegrown system with genesis near FL. The W. Caribbean system would be a totally different system that would form much later per models.

I agree with northjax that this will probably need its own thread soon, especially if it keeps on showing up in models, so as not to overclutter up this models thread and also to prevent confusion with the potential W. Caribbean genesis.

Edit: there are actually at least two different disturbances/micro-lows that models have shown related to this potential home grown system.

[Emmett_Brown]

Yep, the environment for the potential system E of FL doesn't look favorable for a strong system, however, the GFS shows that shear won't be as strong this weekend in the area; perhaps in part to the system creating a bit of its own outflow. Also, an upper level low in the E GOM will help to vent it a bit, both shearing it a little while enhancing convection. Seems like a medium strength TS is very possible.

[srainhoutx]

Careful with the various deterministic and ensemble members with this large Central America Monsoonal trough/gyre developing next week. We will likely see multiple spurious vortices rotating counter clock wise around a very large area of lowering pressures. As we experience with Cindy back in June in a similar setup, development is often very slow to organize and there likely will be multiple vorts giving the guidance fits.

[LarryWx]

Careful with the various deterministic and ensemble members with this large Central America Monsoonal trough/gyre developing next week. We will likely see multiple spurious vortices rotating counter clock wise around a very large area of lowering pressures. As we experience with Cindy back in June in a similar setup, development is often very slow to organize and there likely will be multiple vorts giving the guidance fits.

Hey Steve,
Any posts I and several others have been making today in this thread have nothing to do with the C.A./W. Caribbean trough/gyre. I'm now referring here to a potential near FL homegrown earlier development from a couple of candidate micro-lows that models have been showing.

[TheStormExpert]

Yeah, the odds would be against a H, period, (despite the very warm SSTs in/near the Bahamas) so close in without great atmospheric conditions based on history (though far from impossible, of course), but even just a TS/STS or even a TD/STD would be of major interest as the last thing FL/se GA would want right now after Irma's deluges/coastal flooding is more heavy rain. Also, just a TS/STS or even a TD/STD could help induce coastal flooding to its north in early Oct. due to the pinching of the gradient in concert with the progged strong NE US surface high as the full moon approaches.

So why would odds be against a powerful hurricane in the Western Caribbean in October?

We have a quickly developing La Niña, warm SST’s, untouched TCHP, light wind shear being hinted, and vertical instability.

Unless due to the fact that it may be lifting north into the Gulf quickly I see no reason to discount chances of a powerful hurricane in the Western Caribbean next month.

In fact models may just be now honing in on the early indications of something down there rather than a system itself in early October as you usually don’t see something coming out of the Western Caribbean until the 2nd or 3rd week in October similar to Irene (1999), or Wilma (2005).

Sorry about the confusion. We're not talking about the W Caribbean system right here now. That now has its own thread. Here we're now dealing with a potential earlier homegrown system with genesis near FL. The W. Caribbean system would be a totally different system that would form much later per models.

I agree with northjax that this will probably need its own thread soon, especially if it keeps on showing up in models, so as not to overclutter up this models thread and also to prevent confusion with the potential W. Caribbean genesis.

Edit: there are actually at least two different disturbances/micro-lows that models have shown related to this potential home grown system.

Sorry thought you were talking about the Western Caribbean potential area.

But yeah I agree with you on the potential short-medium term area(s) near and around Florida. Likely messy weak short-lived Tropical Storm at best.

[joey]

So why would odds be against a powerful hurricane in the Western Caribbean in October?

We have a quickly developing La Niña, warm SST’s, untouched TCHP, light wind shear being hinted, and vertical instability.

Unless due to the fact that it may be lifting north into the Gulf quickly I see no reason to discount chances of a powerful hurricane in the Western Caribbean next month.

In fact models may just be now honing in on the early indications of something down there rather than a system itself in early October as you usually don’t see something coming out of the Western Caribbean until the 2nd or 3rd week in October similar to Irene (1999), or Wilma (2005).

Sorry about the confusion. We're not talking about the W Caribbean system right here now. That now has its own thread. Here we're now dealing with a potential earlier homegrown system with genesis near FL. The W. Caribbean system would be a totally different system that would form much later per models.

I agree with northjax that this will probably need its own thread soon, especially if it keeps on showing up in models, so as not to overclutter up this models thread and also to prevent confusion with the potential W. Caribbean genesis.

Edit: there are actually at least two different disturbances/micro-lows that models have shown related to this potential home grown system.

Sorry thought you were talking about the Western Caribbean potential area.

But yeah I agree with you on the potential short-medium term area(s) near and around Florida. Likely messy weak short-lived Tropical Storm at best.

yep when should we start to be looking for this to start? thanks

[northjaxpro]

If model support continues into tonight, which I see no reason why it would cease given the yrends for possible development near Florida, I think we should start a separate thread on that potential no later than tomorrow morning.

[ronjon]

And here's the separate thread for the east coast Florida low.

http://www.storm2k.org/phpbb2/viewtopic.php?f=31&t=119260

[tropicwatch]

This would be interesting to see if it happened.

[bqknight]

This would be interesting to see if it happened.

Looks like the Euro may be trying to develop something in the Gulf around the same time...worth a watch.

[stormlover2013]

that's 324 hours, euro only goes out to 240 hours

[blp]

I am going to post this in this thread because I am looking at the long term development in the NW Caribbean being modeled.

The THCP is off the charts this year. Compare that to pre Wilma. The only good news might be if it struggles because of how broad the Gyre is being modeled but if it consolidates watch out.

Current:


Pre-Wilma Oct 16 2015