ATL: HELENE - Post-Tropical

[Aric Dunn]

... snip...I'm wondering though were this to develop there, since the primary wave axis seems to still be over Mexico, would this be TD7 again or TD9?
... snip

Good question. It certainly had completely lost its circulation. Not too different from TD #10 in 2005 that became TD #12 and Katrina. I was just looking at satellite images of TD 10, then remnants, then TD 12. Remnants of TD 10 in 2005 looked much more impressive between being 10 and 12 than Seven does now. That would be an argument for it becoming TD 9. However, they kept "Ivan" as Ivan many days after it lost its circulation. So who knows what they'd do?

Although true the nhc has continued this as the remnants of td7 in the outlook so there should be little doubt it would td 7 again.

[wxman57]

... snip...I'm wondering though were this to develop there, since the primary wave axis seems to still be over Mexico, would this be TD7 again or TD9?
... snip

Good question. It certainly had completely lost its circulation. Not too different from TD #10 in 2005 that became TD #12 and Katrina. I was just looking at satellite images of TD 10, then remnants, then TD 12. Remnants of TD 10 in 2005 looked much more impressive between being 10 and 12 than Seven does now. That would be an argument for it becoming TD 9. However, they kept "Ivan" as Ivan many days after it lost its circulation. So who knows what they'd do?

Although true the nhc has continued this as the remnants of td7 in the outlook so there should be little doubt it would td 7 again.

I went back to TD 10/12 in 2005 and the NHC continued the model guidance as "Ten" right up through 8pm the night of the 22nd of August. The next guidance that came out said "Invest 99L", but it was clearly the same system. So the argument that they're calling it remnants of Seven doesn't hold. They called 10 the remnants of 10 in 2005 then called it TD 12.

Anyway, it certainly looks quite impressive on satellite. I've measured a movement toward 295deg at 16-22 kts over the past 6 hrs. It's only 300 miles from land to the WNW, so that would put it inland within 24hrs, assuming it doesn't slow down (which I expect it to do). I'd estimate 40-50% chance it could be a TD by 21Z tomorrow. Current trend of increasing convection and apparent low-level and mid level banding is hard to ignore.

[Aric Dunn]

I t does look quite good this evening. although it is close to land the models do slow its forward motion down prior to moving inland. so we will just have to wait and see.


Also I did not realize they were calling it the remnants in the outlooks for td10.

[Aric Dunn]

notice the steering. its approaching the backside of the high over the northern gulf coast so it should begin to slow and start moving on a more nw track over the next 24 hours which should keep over water longer.

[Portastorm]

Amazing ... watching this system spin up reminds me once more that the GFS again appears to have smacked down the Euro. This is all shaking out just like the GFS suggested days ago and continued to up until last night's 0z run. Those of us in Texas will, obviously, watch with great interest.

[Houstonia]

Houston NWS says little to nothing about it:

AH THE CHANGES THEY ARE A COMING...WEEKEND WEATHER DEFINITELY
TAKING A TURN FOR GREATER PRECIPITATION CHANCES. SATURDAY
AFTERNOON AND SUNDAY MORNING-SUNDAY AFTERNOON LOOKING LIKE THE
BEST CHANCE FOR RAIN IN A LONG TIME. THREAT FOR THE HEAVIEST
RAINFALL SEEMS TO BE SHIFTING SOUTH OUT OF OUR CWA
HOWEVER...NONETHELESS WEEKEND RAINFALL TOTALS SHOULD RANGE IN THE
0.50 TO 1.25 INCH RANGE. DISAGREEMENT AS USUAL IN MODEL GUIDANCE.
ECM PUSHES A WIND SHIFT/PREFRONTAL TROUGH INTO THE CWA SUNDAY
MORNING WITH COLD FRONT/TEMP/TD BOUNDARY LAGGING TO OUR
NORTH...GFS MAINTAINS OFFSHORE FLOW. EVEN WITH THE GOOD TROUGHING
ALOFT OVER THE EAST COAST...IN THE SUMMER SOMETIMES ONSHORE FLOW
AT THE SFC PER THE GFS IS THE BEST COURSE. ONLY A FEW OF THE GFS
ENSEMBLES HAVE ECM-LIKE SOLUTIONS. BY MON/TUE MOST GUIDANCE KEEPS
PCPN OFFSHORE BUT ENOUGH UNCERTAINTY TO CARRY 20-30 POPS. 04

&&

&&

.MARINE...
WAA TYPE SHRAS/TSRAS TO LINGER FOR THE REST OF THE AFTN BUT COVERAGE
MIGHT BE A BIT CLOSER TO THE COAST EARLY TOMORROW MORNING. OTHERWISE
NOT A LOT OF CHANGES TO THE GOING FCST TREND OF LIGHT/MODERATE WINDS
FROM THE S/SE THE NEXT FEW DAYS. SEAS COULD PICK UP OVER THE WEEKEND
IF THINGS DO DEVELOP OVER THE BAY OF CAMPECHE...SO ALL MARINERS WILL
NEED TO STAY ALERT TO CHANGES THERE. 41

&&

[tailgater]

... snip...I'm wondering though were this to develop there, since the primary wave axis seems to still be over Mexico, would this be TD7 again or TD9?
... snip

Good question. It certainly had completely lost its circulation. Not too different from TD #10 in 2005 that became TD #12 and Katrina. I was just looking at satellite images of TD 10, then remnants, then TD 12. Remnants of TD 10 in 2005 looked much more impressive between being 10 and 12 than Seven does now. That would be an argument for it becoming TD 9. However, they kept "Ivan" as Ivan many days after it lost its circulation. So who knows what they'd do?

I agree( not that it matters) should be TD 9 if it becomes a TD.
57 correct me if I'm wrong but as far as the movement of this vorticy would you say it being pushed by ex TD7 but if or when it becomes deeper than ex TD 7 it would more likely take it's own course, ie slower and maybe a little closer to a NW direction?

[Aric Dunn]

... snip...I'm wondering though were this to develop there, since the primary wave axis seems to still be over Mexico, would this be TD7 again or TD9?
... snip

Good question. It certainly had completely lost its circulation. Not too different from TD #10 in 2005 that became TD #12 and Katrina. I was just looking at satellite images of TD 10, then remnants, then TD 12. Remnants of TD 10 in 2005 looked much more impressive between being 10 and 12 than Seven does now. That would be an argument for it becoming TD 9. However, they kept "Ivan" as Ivan many days after it lost its circulation. So who knows what they'd do?

I agree( not that it matters) should be TD 9 if it becomes a TD.
57 correct me if I'm wrong but as far as the movement of this vorticy would you say it being pushed by ex TD7 but if or when it becomes deeper than ex TD 7 it would more likely take it's own course, ie slower and maybe a little closer to a NW direction?

being that it is td7's remnants ( per the NHC ) its not pushing its self. Also systems like this are steered by large scale features and in this case would be the low to mid level ridging along the northern gulf coast and southern US.

[tailgater]

The Circulation center of ex TD 7 could be followed pretty much along the 15th or 16th degree north LAT through out most of it's life and this morning looked to be near the Gulf of Tehuantepec, but this vorticy crossed the Yucatan just north of Belize last nite so while it may have be a piece of ex TD 7, I think it was just rotating around the Circulation.

[Aric Dunn]

:uarrow: The Circulation center of ex TD 7 could be followed pretty much along the 15th or 16th degree north LAT through out most of it's life and this morning looked to be near the Gulf of Tehuantepec, but this vorticy crossed the Yucatan just north of Belize last nite so while it may have be a piece of ex TD 7, I think it was just rotating around the Circulation.

there has not been a circulation since it opened up to a wave and downgraded. so it has only been a wave axis that extending south to north and the northern half is now in the BOC

[MGC]

Sure does look like something is trying to spin up down in the BOC....be it TD7 or TD9 it don't really matter. Something to keep an eye on. I'l go out on a limb and give it a 50/50 chance of getting named....MGC

[ROCK]

I am impressed... what looks to be banding features beginning to take shape.

[Portastorm]

Think I've been staring at the satellite loops too long. I see some kind of center at 20/94 ... probablyk mid level? Pulling out visually some, it looks like a larger circulation kinda encompasses most of the southern BOC.

Does look better and better as time moves on. But there's not much room before it goes over land again. One thing's for sure ... there's a lot of moisture headed into south Texas per the WV loop.

[NDG]

Think I've been staring at the satellite loops too long. I see some kind of center at 20/94 ... probablyk mid level? Pulling out visually some, it looks like a larger circulation kinda encompasses most of the southern BOC.

Does look better and better as time moves on. But there's not much room before it goes over land again. One thing's for sure ... there's a lot of moisture headed into south Texas per the WV loop.

That is the location that I have been tracking since earlier this morning but it looks to be dying out and does not look like is at the surface. The surface trough looks to be east of that vorticity.

[NDG]

Not that well organized yet, IMO.

[cycloneye]

Up to 40%

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT THU AUG 16 2012

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM GORDON...LOCATED OVER THE CENTRAL ATLANTIC ABOUT 745 MILES
EAST-NORTHEAST OF BERMUDA.

SHOWER ACTIVITY...ASSOCIATED WITH THE REMNANTS OF TROPICAL
DEPRESSION SEVEN...IS SHOWING SOME SIGNS OF ORGANIZATION IN THE
EXTREME SOUTHWESTERN GULF OF MEXICO. ENVIRONMENTAL CONDITIONS
APPEAR CONDUCIVE FOR GRADUAL DEVELOPMENT DURING THE NEXT DAY
OR TWO...AND AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS
SCHEDULED TO INVESTIGATE THIS DISTURBANCE TOMORROW AFTERNOON...IF
NECESSARY. THIS SYSTEM HAS A MEDIUM CHANCE...40 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES
WEST-NORTHWESTWARD TO NORTHWESTWARD AROUND 10 MPH.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER KIMBERLAIN/AVILA

[NDG]

Not that well organized yet, IMO.

http://www.nrlmry.navy.mil/tcdat/tc12/A ... W.87pc.jpg

Actually, the more I look at the picture the more I see some cyclonic banding though it lacks deep convection where it appears to be the COC.

[ROCK]

I still dont get why this is TD7...that low level circulation has long since been dead over MX....still though I have switch my eyes over to that MCS moving off the Yucatan.....

[cycloneye]

00z Best Track

AL, 07, 2012081700, , BEST, 0, 201N, 939W, 20, 1011, LO

ftp://ftp.nhc.noaa.gov/atcf/tcweb/inves ... 012.invest

[Tireman4]

Very interesting days ahead folks.......