2015 Global model runs discussion

[blp]

Still some interesting differences between the Euro and GFS in terms of genesis. The Euro wants to develop this in the BOC while the GFS wants to develop in W. Carribbean. Let's see which one is right.

[NDG]

:uarrow: NDG, ordinarily I would agree that the front wouldn't make it that far south but it does not have the flattened out west to east look yet. So I think it will make it quite further south. jmo

It is forecasted to become stationary along the northern gulf coast over the next couple of days, not much cooler air behind it, just drier air. Notice that the GFS shows development in the NW Caribbean, the front would have to move all the way down to the southern GOM if not the NW Caribbean if the disturbance was to develop from the frontal boundary.
The GFS does show the southern branch of the jet stream to dig down across the eastern GOM and become almost cut off but it does not mean that the cold front will move that far south, by the UL trough digging that far south is what I think will get UL divergence going in the NW Caribbean and blossom up convection by the end of the week in the western Caribbean.

[Ntxw]

Meanwhile last night's Euro starts development but over the BOC, moves it northward towards the central gulf coast, it shows it be more of a hybrid system:

http://www.tropicaltidbits.com/analysis ... atl_10.png

I think I favor the Yucatan development more. That ULL sitting in Louisiana-ish is throwing up to 50knts + of shear in the WGOM. You're right though, has to be hybrid with that kind of shear sitting there. Otherwise it will become another rain axis for flooding which either way it will likely be for Florida or the northern gom.

[N2FSU]

0Z Canadian; +186hr

[gatorcane]

Most of the GFS Ensembles are showing something in the NW Carib that moves northward into the EGOM. On the 06Z a lot of them are clustered in the SE GOM at 210 hours:

[LarryWx]

Six of those ~20 6Z GEFS members would suggest hurricane strength if truly tropical fwiw. Zoom in on the red numbers. These six range from 977 mb to 993 mb and these are not necessarily their strongest at that point since most of those (5 of the 6) are still well down into the GOM with many more hours to travel over the warm E GOM. Also, the operational was the strongest yet of any GFS run with 999 mb at its strongest in the E GOM, which would suggest strong tropical storm strength if truly tropical.

Edit: 8 others are in the 990's of mb's. So, a total of 14 of the ~20 members are 999 or stronger. Most of those 14 would probably get very close to, if not into, H strength since most are still well out into the GOM. As mentioned, 6 of the 20 would quite possibly already be at H strength at that time.

[TheStormExpert]

FWIW the 06z GFS shows a 996mb system at peak on the high-resolution just as it's offshore Destin, FL approaching them.

Still not buying this one bit with all the shear that's been in the GoM since early/mid July. The Euro probably has a better handle on strength and evolution on how this evolves.

[PTrackerLA]

:uarrow: Six of those ~20 6Z GEFS members would suggest hurricane strength if truly tropical fwiw. Zoom in on the red numbers. These six range from 977 mb to 993 mb and these are not necessarily their strongest at that point since most of those (5 of the 6) are still well down into the GOM with many more hours to travel over the warm E GOM. Also, the operational was the strongest yet of any GFS run with 999 mb at its strongest in the E GOM, which would suggest strong tropical storm strength if truly tropical.

Edit: 8 others are in the 990's of mb's. So, a total of 14 of the ~20 members are 999 or stronger.

Actually see 996mb on the tropical tidbits Full-res. Something to keep an eye on through the week for now.

[LarryWx]

Thanks. So, 996 mb on the high resolution 6Z GFS. Also, upon further review of the ~20 6Z GEFS members, I see about half (10) with lowest SLP of low 990's or lower. These 10 would all likely be approaching minimal H strength or stronger.

I think that someone should start a new thread on this soon if this threat continues to show. I don't think we should wait for invest status on this one to do so.

[Frank2]

Shear being what it is, I wouldn't get too excited about any model at this point - as others said, the shear isn't likely to go away, with El Nino as strong as it's becoming...

[floridasun78]

Shear being what it is, I wouldn't get too excited about any model at this point - as others said, the shear isn't likely to go away, with El Nino as strong as it's becoming...

but with strong El Nino already at letter L that strong El Nino not keeping storm forming alot here was think we still letter H

[wxman57]

I'm quite skeptical of this system, as I was about the EC's prediction of a Cat 2 hurricane hitting Louisiana in the recent past. Models appear to be developing a surface reflection of a deep upper-level trof. Euro has the trof axis farther west, thus the BoC development. Both indicate relatively strong wind shear across the Gulf. I'm thinking there may be the potential for a low pressure area to form, but it will be fighting strong wind shear. That may not prevent it from reaching 35-45 mph intensity (right of the center). I wouldn't bet that any U.S. city will observe sustained TS winds next week.

[floridasun78]

:uarrow: Thanks. So, 996 mb on the high resolution 6Z GFS. Also, upon further review of the ~20 6Z GEFS members, I see about half (10) with lowest SLP of low 990's or lower. These 10 would all likely be approaching minimal H strength or stronger.

I think that someone should start a new thread on this soon if this threat continues to show. I don't think we should wait for invest status on this one to do so.

i dont see invest if any untill Friday or sat

[floridasun78]

I'm quite skeptical of this system, as I was about the EC's prediction of a Cat 2 hurricane hitting Louisiana in the recent past. Models appear to be developing a surface reflection of a deep upper-level trof. Euro has the trof axis farther west, thus the BoC development. Both indicate relatively strong wind shear across the Gulf. I'm thinking there may be the potential for a low pressure area to form, but it will be fighting strong wind shear. That may not prevent it from reaching 35-45 mph intensity (right of the center). I wouldn't bet that any U.S. city will observe sustained TS winds next week.

wx too far to tell what we see by friday if any thing

[LarryWx]

:uarrow: Thanks. So, 996 mb on the high resolution 6Z GFS. Also, upon further review of the ~20 6Z GEFS members, I see about half (10) with lowest SLP of low 990's or lower. These 10 would all likely be approaching minimal H strength or stronger.

I think that someone should start a new thread on this soon if this threat continues to show. I don't think we should wait for invest status on this one to do so.

i dont see invest if any untill Friday or sat

Yeah, if this continues to be a threat and is not given invest status til Friday or Saturday, I think that would be too long to continue posting about this in this general models thread. It could approach 75 pages by then at this rate (now at 56). Just my opinion. No big deal either way.

Considering that this is still ~7-10 days out from potentially impacting land, it isn't too often that the models including ensemble members are this much in agreement on at least suggesting a threat that far out in time.

[LarryWx]

I'm quite skeptical of this system, as I was about the EC's prediction of a Cat 2 hurricane hitting Louisiana in the recent past. Models appear to be developing a surface reflection of a deep upper-level trof. Euro has the trof axis farther west, thus the BoC development. Both indicate relatively strong wind shear across the Gulf. I'm thinking there may be the potential for a low pressure area to form, but it will be fighting strong wind shear. That may not prevent it from reaching 35-45 mph intensity (right of the center). I wouldn't bet that any U.S. city will observe sustained TS winds next week.

wxman57,
With all due respect to your great knowledge and skills that we're lucky to have here and although you may end up being right, I think that this is a far different situation from the Euro's LA H hit prediction from 94L. I, like you, never bought into the crazy quick Euro strengthening on those runs because it did it so fast and barely offshore the western GOM coast. Also, the Euro was on its own and even its own ensemble members as well as the control runs pretty much disagreed. In this case, the projected development is much further into open water for the most part and is much more gradual/reasonable. Also, there is actual model consensus (including many ensemble members of various models) in the current case. Furthermore, climo for late Sep. is much more supportive of the upcoming projected scenario than that pretty far-fetched 94L Euro sudden strengthening barely offshore the western GOM coast, which has hardly at best ever happened in over 100 years of records. It had a bogus look to it unlike this one IMO. Whereas this one is still far from definite, I just don't see it being comparable to the crazy Euro's 94L runs. Regardless, shear does, indeed, look like an issue in the mix most likely.

[blp]

12z slightly weaker due to more interaction with Yucatan and is slower than the 06z run.

[blp]

The Mjo is going to make a push toward the end of the month into our region. This should help the area we are looking at.

[NDG]

12z slightly weaker due to more interaction with Yucatan and is slower than the 06z run.

Not so much because of land interaction with Yucatan, it shows it loosing strength and tropical characteristics due to the high shear as it moves northward across the central GOM.

[HURRICANELONNY]

I see a little spin down there.....

http://www.ssd.noaa.gov/goes/east/gmex/flash-wv.html