ATL: DEBBY - Post-Tropical

[Ntxw]

The model shift today was due to the formation of the Sonoran ridge. It gave better sampling to the models of how the mid-latitude weather pattern will behave *IF* there is a significant tropical system. I don't believe there will be much change in the model shifts tonight's 0z (unless the GFS decides to get the convective feedback issues resolved.) The ridge will expand eastward tomorrow which will give additional data for the 12z run and that is when we'll likely see more changes if any. The rest is up to the system initialization in terms of intensity.

[MiamiHurricanes10]

I meant how good is it.

Utterly useless. The NAM should not be used for prognosticating tropical cyclones. If anything, the only use it has when looking on the tropical side of things, is that it can be fairly useful for predicting the evolution of steering currents over the United States. Other than that, the NAM should be thrown in the bin if you're tracking the tropics.

[EmeraldCoast93]

Afternoon discussions from NWS offices.

<snip>

Sounds like texas and LA are trying to send it to florida and florida trying to push it to texas! lol

Interesting thing about the NWS Mobile/Pensacola AFD is an exact copy/paste from this morning's AFD. But the HWO from them (updated at 12:13 PM) paints a different picture than their discussion

.DAYS TWO THROUGH SEVEN...FRIDAY AFTERNOON THROUGH NEXT WEDNESDAY

IT APPEARS THAT A SURFACE LOW PRESSURE SYSTEM WILL DEVELOP IN THE SOUTHERN
GULF OF MEXICO OVERNIGHT. THE LONG RANGE FORECAST FOR OUR REGION IS
UNCERTAIN IN THE SENSE THAT WE DO NOT KNOW PRECISELY WHERE THE LOW
WILL FORM..AND ONCE FORMED...THERE IS STILL CONSIDERABLE DISAGREEMENT ON
EXACTLY WHERE IT WOULD MOVE. THERE IS ALSO DISAGREEMENT ON THE INTENSITY
OF THE SURFACE LOW PRESSURE SYSTEM.

RECENT CONSENSUS SEEMS TO BE FAVORING A MORE WESTERLY TRACK WHICH
WOULD PLACE THE CENTRAL GULF COAST REGION UNDER AT LEAST THE THREAT
OF SOME HEAVY RAINS...MINOR COASTAL FLOODING AND AN ELEVATED RIP
CURRENT RISK. IF YOU LIVE ALONG THE CENTRAL GULF COAST REGION YOU
MAY WANT TO BEGIN THINKING ABOUT MAKING PREPARATIONS FOR LATE WEEKEND
THROUGH EARLY NEXT WEEK DUE TO THE IMPACTS ASSOCIATED WITH THE
DEVELOPMENT OF A GULF LOW PRESSURE SYSTEM. THE POTENTIAL FOR THE
ONSET OF HEAVY RAINS COULD ONSET BY LATE SUNDAY.

[caneman]

Can tell something is brewing here from West Pen. Florida. Very windy, gusty and blowing rain. Very much tropical.

[TropicalAnalystwx13]

Can tell something is brewing here from West Pen. Florida. Very windy, gusty and blowing rain. Very much tropical.

Well, there's a developing tropical cyclone a few hundred miles south and west of you.

['CaneFreak]

I see some signs of some organized outer bands starting to form on the east side of this massive cloud debris. Look closely at the last few frames of this visible loop, especially along 85 W parallel.

EDIT: I think the eastern most portion of this large blob of vorticity is going to win out here.

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

[blazess556]

Merida / lic Manuel Crecencio, (MMMD)
Elev: 11 ft; Latitude: 20.94686; Longitude: -89.65214

It is reporting 1006.8 mb.

['CaneFreak]

Lots of convergence to the north of this area that I mentioned.

http://tropic.ssec.wisc.edu/real-time/w ... oom=&time=

I see some signs of some organized outer bands starting to form on the east side of this massive cloud debris. Look closely at the last few frames of this visible loop, especially along 85 W parallel.

EDIT: I think the eastern most portion of this large blob of vorticity is going to win out here.

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

[wxman57]

Definitely a good reason for NHC to up development chances this evening. 6 more hours of development time in the 48 hr outlook. BY 8pm Saturday I expect it to be a strengthening TS.

[TheShrimper]

Still over land drifting ENE IMO.

I agree. Winds are out of the north in Merida and Campeche and out of the south in Cancun and Cozumel. Granted the circulation is broad and ill defined visible shows also what you are eluding to Sanibel..... inland moving between ENE and ESE.

[cycloneye]

:uarrow: Yeah, if the quoted text is really long, it would be better to avoid quoting it. In fairness, a lot of people don't realize how long it makes the thread.

That is correct. Myself or others may do the same posting of AFD's in the future on one post to not make different posts of the different NWS offices.And no quoating of those long posts.

[Lane]

Off Topic: I sure have missed you all

On topic: I do have a question about the ridge/trough that maybe starting to make the models go west. Could the trough/ridge end up being weaker than forecast causing another change/shift in models?

[Dean4Storms]

Need to see this consistently by the ECMWF before everyone gets too excited. All will depend on the depth of the storm, its position and how much the eastern trough digs. One hundred miles further north/south, east/west could make all the difference in the world with this storm!

[caneman]

Need to see this consistently by the ECMWF before everyone gets too excited. All will depend on the depth of the storm, its position and how much the eastern trough digs. One hundred miles further north/south, east/west could make all the difference in the world with this storm!

Indeed. And not ready to buy a 1,0000 mile shift from the Euro as that hardly adds confidence but we shall we how it plays out.

[tailgater]

Looks like it's trying to develop on shore, which if I'm not mistaken, would not be the first time it's happen in this area. Still has quite a ways to go yet.

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

[Javlin]

It sure does look like something is trying alittle further E as Aric eluded to earlier around 86-87' and 22'N maybe?

http://www.ssd.noaa.gov/PS/TROP/floater ... -long.html

[Dean4Storms]

Did anyone notice that in the 12z ECMWF run it moves the Low to the WNW to around 23N 91W at 48 hours??

If this move doesn't occur which I think is highly suspect then this run might not pan out IMO.


http://raleighwx.americanwx.com/models/ ... _loop.html

[johngaltfla]

Definitely a good reason for NHC to up development chances this evening. 6 more hours of development time in the 48 hr outlook. BY 8pm Saturday I expect it to be a strengthening TS.

I don't mean to sound sadistic, but a nice TS sweeping through here would cure our drought AND since I'm on a road trip to the USVI/BVI next week, that should help to suck all the storms north of there.

However, folks, I've been through quite a few strong TS, and PLEASE take precautions for flooding seriously, even if your "officials" say you are not in a flood plain in Florida. It doesn't take much on the West Coast of Florida to cause a flood once the ground is saturated.

[Ntxw]

On topic: I do have a question about the ridge/trough that maybe starting to make the models go west. Could the trough/ridge end up being weaker than forecast causing another change/shift in models?

Key will be the ridge. The trough is already in existence and heading east/northeast. The -NAO will allow it to deepen along the east coast. If this system were to evolve quickly it would race to Florida and quickly move through the Peninsula with the trough. This is why the GFS not long ago showed it already off the east coast of FL for several runs. A stronger elongated ridge will tend to swing the models west. A caveat of a stronger east coast trough is shear would then quickly rip it apart (again why GFS has not been gun-ho as the other models in intensity). So really the upcoming ridge is very important for the models as changes in it can have different solutions per model runs.

[cycloneye]

Organizing just inland in northern Yucatan.