ATL: DORIAN - Post-Tropical - Discussion

[Aric Dunn]

Convection still increasing but at a slower rate. Probably still ingesting the rest of the dry air.

if you go frame by frame you can see -60 to -70 tops popping up and moving around.. the convection is sustaining so far and expanding... its all right around the center which is odd.

[blp]

Convection still increasing but at a slower rate. Probably still ingesting the rest of the dry air.

[]http://i189.photobucket.com/albums/z174/philnyc_2007/satavn2013-07-270515_zpsec114120.jpg[/img]

Yes indeed, it has in my opinion done exactly what it needed to do to stay alive and has exceeded my expectations so far.

[blp]

Convection still increasing but at a slower rate. Probably still ingesting the rest of the dry air.

[]http://i189.photobucket.com/albums/z174/philnyc_2007/satavn2013-07-270515_zpsec114120.jpg[/img]

if you go frame by frame you can see -60 to -70 tops popping up and moving around.. the convection is sustaining so far and expanding... its all right around the center which is odd.

Aric, what do you think will happen in a few days, do you see the environment in the Bahamas being very hostile?

[ozonepete]

Convection still increasing but at a slower rate. Probably still ingesting the rest of the dry air.

if you go frame by frame you can see -60 to -70 tops popping up and moving around.. the convection is sustaining so far and expanding... its all right around the center which is odd.

I see that. But that's what it should be trying to do if it's strengthening: I would think there must be a lot of instability now with low shear which is allowing the individual thunderstorms to pop and try to rotate around that center. But they don't necessarily have to rotate around the original center - sometimes they'll just find their own new one near it. That's why the convective area isn't symmetrical yet. (I learned most of this from you btw, lol) Ok, I learned most of the theory from Penn State but most of the observational skills from you.

[Aric Dunn]

Convection still increasing but at a slower rate. Probably still ingesting the rest of the dry air.

if you go frame by frame you can see -60 to -70 tops popping up and moving around.. the convection is sustaining so far and expanding... its all right around the center which is odd.

I see that. But that's what it should be trying to do if it's strengthening: I would think there must be a lot of instability now with low shear which is allowing the individual thunderstorms to pop and try to rotate around that center. But they don't necessarily have to rotate around the original center - sometimes they'll just find their own new one near it. That's why the convective area isn't symmetrical yet. (I learned most of this from you btw, lol)

yeah right now its finding every avenue of instability that is around..

[Fego]

Latest at 0600. I hope this loop doesn't violate any rule.

http://images.intellicast.com/WxImages/ ... e_anim.gif

[Aric Dunn]

Convection still increasing but at a slower rate. Probably still ingesting the rest of the dry air.

[]http://i189.photobucket.com/albums/z174/philnyc_2007/satavn2013-07-270515_zpsec114120.jpg[/img]

if you go frame by frame you can see -60 to -70 tops popping up and moving around.. the convection is sustaining so far and expanding... its all right around the center which is odd.

Aric, what do you think will happen in a few days, do you see the environment in the Bahamas being very hostile?

very hard to say.. according the models it could very well be at least good enough to have a little intensification. that is a very large TUTT in the way and there are too many variables to be accurate atm. just have to watch and see if it can even survive the next couple days

[NDG]

Yeah, convection continues refiring around the COC.

[fci]

Well it will be amusing reading everyone chasing the ghost of Dorian until the next system come along.

[ROCK]

Dorian looks like a TD to me if that tonight. I have seen bigger Tstorms...

[Ivanhater]

:lol: Dorian looks like a TD to me if that tonight. I have seen bigger Tstorms...

Keep the faith Rock!

[Hammy]

latest ASCAT from roughly an hour ago still showing closed circulation and tropical storm force winds by the looks of it.

http://manati.star.nesdis.noaa.gov/ascat_images/cur_25km_TEST/zooms/WMBds112.png

[Hurricane Alexis]

latest ASCAT from roughly an hour ago still showing closed circulation and tropical storm force winds by the looks of it.

http://manati.star.nesdis.noaa.gov/ascat_images/cur_25km_TEST/zooms/WMBds112.png

That pass is 12 hours old.

[Hammy]

latest ASCAT from roughly an hour ago still showing closed circulation and tropical storm force winds by the looks of it.

http://manati.star.nesdis.noaa.gov/ascat_images/cur_25km_TEST/zooms/WMBds112.png

That pass is 12 hours old.

ah, I think I got the time at the top confused with the pass time...

also, to the earlier discussion as to an instance where the MLC dissipated and the system still redeveloped, Nicole in 1998 was one example i found
http://199.9.2.143/tcdat/tc98/ATL/14.NICOLE/vis/geo/1km/19981126.1115.g8.vis.x.NICOLE.x.jpg
http://199.9.2.143/tcdat/tc98/ATL/14.NICOLE/vis/geo/1km/19981127.1415.g8.vis.x.NICOLE.x.jpg

[beoumont]

Convection increased (bursting) as center reached longitude 48. Hmmmmm.

un-poofing, or last gasping?

SST's

[bahamaswx]

Looks like his new "CDO" has finished expanding. We'll see how long it can maintain.

[Hurricane Alexis]

Dry air seems to be lessening in and around Dorian.




Uploaded with ImageShack.us

[USTropics]

First visible images of the day. The small popcorn convection developing to the west of the center is a good indication that shear has lessened and the environment is becoming more moist around Dorian despite the dry air.

[Hurricane Alexis]

Shear increase right ahead of it according to the shear map, but also shows it decreasing within the next day.


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[cycloneye]

TCDAT4

TROPICAL STORM DORIAN DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042013
500 AM AST SAT JUL 27 2013

DISORGANIZED CONVECTION HAS DEVELOPED NEAR THE CENTER OF DORIAN
DURING THE PAST SEVERAL HOURS. HOWEVER...WATER VAPOR IMAGERY SHOWS
WIDESPREAD MID-/UPPER-LEVEL DRY AIR NEAR THE CYCLONE...WHICH
SUGGESTS THIS CONVECTION COULD BE SHORT-LIVED. THE INITIAL
INTENSITY IS KEPT AT 35 KT BASED ON A SATELLITE INTENSITY ESTIMATE
FROM TAFB AND EARLIER ASCAT DATA. IT SHOULD BE NOTED THAT RECENT
OSCAT DATA SUGGESTS THE POSSIBILITY THAT DORIAN NO LONGER HAS A
CLOSED CIRCULATION.

THE INITIAL MOTION IS 275/19. A STRONG LOW-/MID-LEVEL RIDGE NORTH
OF DORIAN IS EXPECTED TO STEER THE CYCLONE QUICKLY WESTWARD FOR THE
NEXT 72 HR. THE TRACK GUIDANCE IS IN GOOD AGREEMENT WITH THIS
SCENARIO...AND THE NEW TRACK FORECAST IS AN UPDATE OF THE PREVIOUS
FORECAST.

DORIAN IS FORECAST TO EXPERIENCE 15-20 KT OF VERTICAL WIND SHEAR
DURING THE FORECAST PERIOD...AS WELL AS MOVE THROUGH A DRY
MID-/UPPER-LEVEL AIR MASS. THIS COMBINATION SHOULD CAUSE
ADDITIONAL WEAKENING...WITH THE CYCLONE DEGENERATING TO A REMNANT
LOW BY 36 HR. AN ALTERNATIVE SCENARIO IS THAT THE SYSTEM COULD
DEGENERATE TO A TROPICAL WAVE AT ANY TIME DURING THE NEXT 72 HR...
AND THUS DISSIPATE EARLIER THAN CURRENTLY FORECAST. UPPER-LEVEL
WINDS IN THE AREA WEST OF THE FORECAST POINT OF DISSIPATION ARE NOT
EXPECTED TO BE CONDUCIVE FOR RE-GENERATION AT THIS TIME.

FORECAST POSITIONS AND MAX WINDS

INIT 27/0900Z 18.2N 50.0W 35 KT 40 MPH
12H 27/1800Z 18.6N 53.1W 30 KT 35 MPH
24H 28/0600Z 19.2N 57.2W 30 KT 35 MPH
36H 28/1800Z 19.8N 61.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 29/0600Z 20.4N 64.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 30/0600Z 21.0N 71.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 31/0600Z...DISSIPATED

$$
FORECASTER BEVEN