ATL: CHANTAL - Post-Tropical

[meriland23]

18z run shows stronger system past hisp/into carribean.. no dissipation..

http://www.tropicaltidbits.com/analysis ... t_atl.html


this is the 12z run

http://www.tropicaltidbits.com/analysis ... t_atl.html

[Aric Dunn]

Are you guys buying the strength of the Trough and subsequent Cut-off low left behind it?

yeah, being that the low is already in place.

[Aric Dunn]

108 hr ridge building in .... turning wnw toward jax.. very similar solution yesterday

[MortisFL]

108 hr ridge building in .... turning wnw toward jax.. very similar solution yesterday

I didn't think Jax were allowed to get storms? lol jk.

[SouthFloridawx]

Not the current ULL over Florida. If you run the following loop, you will see the trough dipping down into the Great Lakes and the Eastern US... Then as the Trough pulls out it leaves a cut-off low the retrogrades Westward through the Ohio Valley.

Please run this loop...

http://mag.ncep.noaa.gov/list_files_area.php?model=gfs&cycle=18&area=atlantic&param=500_vort_ht

Are you guys buying the strength of the Trough and subsequent Cut-off low left behind it?

yeah, being that the low is already in place.

[Hurricaneman]

Now that I look at it the LLCC and the other levels separate at 48hrs over Hispaniola and the LLCC moves back to the western part of the 850 and 500 lows stacking them once the LLCC leaves Cuba at 66 hrs

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[storm4u]

12z and 18z gfs are so much different with all features its hard to trust either run

[tolakram]

12z and 18z gfs are so much different with all features its hard to trust either run

True, but I think the overall signal is clear. Chantal will either be blown apart from shear or torn apart by Hispaniola and it's a real question weather or not it can reform. At least that's what the GFS and Euro runs are telling me.

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[Aric Dunn]

12z and 18z gfs are so much different with all features its hard to trust either run

throw the 12z out.. the 18z is similar to all the previous runs for the past 3 days. the 12z run to day is the only one showing a different synoptic setup.

[SouthFloridawx]

Aric, did you see my response about the cut-off low on the previous page?

['CaneFreak]

This is a good observation. Given the current and past conditions, yes I believe that it will cut off and retrograde westward. If you will remember, this same trough split situation occurred in the central Atlantic a few days ago and that is how this current upper low over FL came into existence.

Not the current ULL over Florida. If you run the following loop, you will see the trough dipping down into the Great Lakes and the Eastern US... Then as the Trough pulls out it leaves a cut-off low the retrogrades Westward through the Ohio Valley.

Please run this loop...

http://mag.ncep.noaa.gov/list_files_area.php?model=gfs&cycle=18&area=atlantic&param=500_vort_ht

Are you guys buying the strength of the Trough and subsequent Cut-off low left behind it?

[Aric Dunn]

Aric, did you see my response about the cut-off low on the previous page?

I did, I was talking about the current low.. that low will phase with the trough leaving the weakness a seperate low forms and begins to move west. the ohio valley low been doing the same thing for many runs except the todays 12z which kicked it out to sea instead of retrograding it. The period from 72hr to 108 hr is the important part while over water.

[SouthFloridawx]

IMHO, I believe it will the strength of the trough and the cut-off low that will determine the ultimate evolution of Chantall after she crosses Hispaniola.

The stronger the Trough and Low the farther north Chantall will travel.

If the trough is not as strong the ridge will not weaken as much and the remnants of Chantall will move across Florida into the the GOM.

This is not an official forecast and should not be taken as one. Please refer to the http://www.nhc.noaa.gov for the official forecast.

Aric, did you see my response about the cut-off low on the previous page?

I did, I was talking about the current low.. that low will phase with the trough leaving the weakness a seperate low forms and begins to move west. the ohio valley low been doing the same thing for many runs except the todays 12z which kicked it out to sea instead of retrograding it.

[artist]

good loop of how much she has grown today

http://rammb.cira.colostate.edu/ramsdis ... asec4vis04

[ozonepete]

Usually that is not a good sign wrt to intensification, is it not?

It depends. If the outflow boundary and all of the area behind it quickly erupts with deep convection (as has been happening with Chantal today) then it doesn't mean anything. It's when outflow boundaries get produced and no new convection fires up near them that one should suspect dry air is winning out.

Pete, what's your take on today's model flip flops?

Ha ha - a loaded question. But really, it all makes a lot of sense why the models are flip-flopping. You've got the Bermuda High which has been quite strong the last couple of weeks and looks like it will be a big presence for most of the summer. About 10 days ago its western border was right over the eastern seaboard and that allowed a big trough to settle in and cause massive rains up and down the eastern seaboard. Its western edge then pushed westward since last weekend and brought drier and hot weather into the entire area east of the Appalachians while the Midwest got the trough and heavy rains. Now another trough is forecast to settle in over the east as the Bermuda high contracts again slightly. The key is that the northern part of the Bermuda high looks like it may ridge in more strongly than the southern part over the weekend. If that happens the ridge will bulge from the Carolinas to New England but will be weak over the southeast and allow Chantal to move more westward into anywhere from Florida to South Carolina. Right now the models are leaning toward that solution – they just can’t resolve the exact strength of the Bermuda high in the northeast nor where Chantal will first “feel” it and start turning west. That’s a very hard thing to resolve 4-5 days out. So they should bounce back and forth from a landfall between central Florida and South Carolina for a few more runs (a day or two) until they have enough data where they will all get a consensus.
There is also the chance that the ridge won’t build more strongly into the northeast this weekend and then the trough will run more north-south straight up the eastern seaboard and then you’d get more of a classic east coast TC that runs right up into the eastern seaboard. That’s a lower chance but if it becomes likely the models will start showing it in a day or two.
Oh, and of course this all hinges on how much of Chantal is left after DR/Haiti. The models have a lot of trouble with that as well since their Achilles heel is strength, but that will get resolved tomorrow night and Thursday. My gut (and its expanding size and staying power so far) says it will survive…

[SouthFloridawx]

You can watch the evolution of this trough here:

http://www.ssec.wisc.edu/data/geo/index.php?satellite=east&channel=wv&coverage=conus&file=gif&imgoranim=8&anim_method=flash

[robbielyn]

I think she is going to miss her next forecast point to the south

[gatorcane]

12z and 18z gfs are so much different with all features its hard to trust either run

True, but I think the overall signal is clear. Chantal will either be blown apart from shear or torn apart by Hispaniola and it's a real question weather or not it can reform. At least that's what the GFS and Euro runs are telling me.

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

Yes couldn't agree more with that assessment!

[torrea40]

I think she is going to miss her next forecast point to the south

Really...?????

[Evil Jeremy]

Recon underway:

000
URNT15 KNHC 092246
AF306 0303A CHANTAL HDOB 01 20130709
223800 1742N 06449W 0139 ///// 0129 +245 +209 360000 000 /// /// 23
223830 1742N 06449W 0139 ///// 0141 +245 +210 360000 000 /// /// 23
223900 1742N 06449W 0142 00019 0164 +245 +210 360000 000 /// /// 03
223930 1742N 06449W 0142 00019 0159 +245 +229 066007 011 /// /// 03
224000 1742N 06448W 9924 00200 0146 +250 +227 078026 031 /// /// 03
224030 1742N 06446W 9559 00528 0149 +231 +213 086038 041 /// /// 03
224100 1742N 06445W 9141 00916 0148 +210 +171 099044 046 /// /// 03
224130 1742N 06444W 8708 01338 0150 +192 +131 103048 049 /// /// 03
224200 1742N 06443W 8469 01591 0168 +171 +117 104046 048 /// /// 03
224230 1742N 06441W 8447 01615 0171 +170 +125 106045 046 /// /// 03
224300 1742N 06440W 8451 01614 0172 +172 +127 106046 046 /// /// 03
224330 1741N 06439W 8456 01605 0169 +175 +119 107046 046 /// /// 03
224400 1740N 06438W 8456 01607 0170 +174 +119 103047 047 /// /// 03
224430 1739N 06437W 8457 01604 0169 +173 +117 101048 048 /// /// 03
224500 1738N 06436W 8455 01607 0170 +170 +120 101047 048 /// /// 03
224530 1737N 06435W 8454 01608 0172 +170 +119 100046 047 /// /// 03
224600 1737N 06434W 8457 01605 0173 +170 +122 102046 046 /// /// 03
224630 1736N 06433W 8454 01605 0171 +165 +124 104046 046 /// /// 03
224700 1735N 06432W 8457 01603 0172 +165 +128 108045 046 /// /// 03
224730 1735N 06430W 8453 01607 0172 +165 +130 109044 045 /// /// 03
$$
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