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Ex-Helene remnant trof


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I will say the 18z run is fun to look at for Texans. Hanging on hope for a 45 kt system is all we can ask for these days.

Slopgyre ftw. I'll take any rain that this or the front will bring at this point. My pond is getting low and the ranch is bone dry in S Texas...:P

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Don't fret. I just had a momentary lapse myself after taking away my attention from the 94 tease and watching what was happening with Helene. I have no shame.

Yeah, was looking at the paltry reflection of Helene in the 18z GFS when a dark ball appeared on the corner of my eye.

If we compare at how pre-Helene looked yesterday at this time and how she looked like 12 hours later, there's still some slight hope for something better than 45kts, though not much, at least in the short term.

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I'd say it's already dying out, coldest cloud tops are associated with upslope on the western side and there doesn't appear to be any inner core convection. The extreme topography in the region is too much for a tropical cyclone to handle.

I was wondering about the topo in that area, thanks for sharing that, I was wondering if the upslope on the western side wound wrap more dry into the core or more moist air, seems like you answered that. Thanks again.

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I was wondering about the topo in that area, thanks for sharing that, I was wondering if the upslope on the western side wound wrap more dry into the core or more moist air, seems like you answered that. Thanks again.

I chased a hurricane down there-- Karl 2010, which came ashore near Veracruz-- and the mountains really did a number on it as it approached the coast. It was still strong as it came ashore, but not what it could have been: http://icyclone.com/chases/karl-2010.html

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I was wondering about the topo in that area, thanks for sharing that, I was wondering if the upslope on the western side wound wrap more dry into the core or more moist air, seems like you answered that. Thanks again.

No problem, the Sierra Madre Oriental runs down the western side of the Gulf of Mexico, 3000 m rise from sea level over a short area. Undoubtedly some killer dry air from compressional warming.

post-645-0-36289900-1345256276_thumb.png

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I'd say it's already dying out, coldest cloud tops are associated with upslope on the western side and there doesn't appear to be any inner core convection. The extreme topography in the region is too much for a tropical cyclone to handle.

Not saying this is a healthy system, but this is par for the course in this area of the world. The BoC is probably the king of dMin and dMax in the basin. Topography helps spin up disturbances, but also robs convection near sunset because of all the land convection, enhanced by upsloping. By midnight land convection will start to die, and it will flare up near Helene. As long as she is weak, she will be a pulsing storm.

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Not saying this is a healthy system, but this is par for the course in this area of the world. The BoC is probably the king of dMin and dMax in the basin. Topography helps spin up disturbances, but also robs convection near sunset because of all the land convection, enhanced by upsloping. By midnight land convection will start to die, and it will flare up near Helene. As long as she is weak, she will be a pulsing storm.

I don't think this is simply a case of land convection robbing the core, I think it's too close to land already and probably over. I guess we will see who is right and wrong in the next 12 hours.

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;) yep

The BoC has many haters. Nothing new. I recall Bill Read commenting last year at Conference that this part of the Basin is often misunderstood and under estimated. No one expected this to be another Humberto or even Hermine, but the Bay Of Campeche/Western Gulf has throw its share of curveballs that have left even the most 'seasoned' forecasters scratching their head over the years... ;)

Avila in the full package disco...

A HURRICANE HUNTER PLANE INVESTIGATED HELENE FOR SEVERAL HOURS THIS

EVENING AND FOUND THAT THE DEVELOPMENT TREND OBSERVED EARLIER TODAY

IS NO LONGER OCCURRING. HELENE IS EITHER WEAKER OR ON A STEADY

STATE WITH MAXIMUM WINDS OF 35 KNOTS. THE CYCLONE STILL HAS A WELL

DEFINED CIRCULATION AS INDICATED BY THE RECONNAISSANCE PLANE BEFORE

IT LEFT THE AREA...AND ALTHOUGH THE SATELLITE PRESENTATION HAS

DETERIORATED...ENVIRONMENTAL CONDITIONS ARE SOMEWHAT FAVORABLE FOR

HELENE TO REGAIN SOME STRENGTH BEFORE IT MOVES INLAND IN ABOUT 24

HOURS OR EARLIER. AFTER LANDFALL...A STEADY WEAKENING IS

ANTICIPATED.

FIXES FROM THE RECONNAISSANCE PLANE INDICATE THAT HELENE WAS

MEANDERING OR DRIFTING NORTHWARD DURING THE PAST COUPLE OF HOURS.

HOWEVER...THERE IS ENOUGH RIDGING TO THE NORTH OF THE CYCLONE TO

FORCE HELENE SLOWLY NORTHWESTWARD AT ABOUT 6 KNOTS TOWARD THE COAST

OF MEXICO. ALTHOUGH THIS IS THE MOST LIKELY SCENARIO AS INDICATED IN

THE OFFICIAL FORECAST...ONE SHOULD NOTE THAT VARIOUS MODELS

INCLUDING THE GFS AND THE ECMWF KEEP A LOW...OR PERHAPS THE MODEL

REPRESENTATION OF HELENE DRIFTING NORTHWARD VERY CLOSE TO THE COAST

OF MEXICO FOR SEVERAL DAYS...AND IN FACT...THE GFS RESTRENGTHENS

THIS FEATURE.

NEVERTHELESS...THE MAIN THREAT FROM HELENE WILL BE HEAVY

RAINFALL...WHICH WILL CONTINUE EVEN AS THE CYCLONE SLOWLY MOVES

INLAND AND WEAKENS.

FORECAST POSITIONS AND MAX WINDS

INIT 18/0300Z 21.0N 96.4W 35 KT 40 MPH

12H 18/1200Z 21.7N 97.2W 40 KT 45 MPH

24H 19/0000Z 22.2N 97.8W 45 KT 50 MPH...ON THE COAST

36H 19/1200Z 23.0N 98.0W 30 KT 35 MPH...INLAND

48H 20/0000Z 24.0N 98.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

72H 21/0000Z...DISSIPATED

$$

FORECASTER AVILA

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Josh and Turtle....Thanks for your answers, I can understand compressional warming as the winds create friction. My next question is this, could the wind speeds pick up on the lee of the mountain range and as they move into the SW quad of the storm, could they scoop up enough moisture over water to enhance the convection on the NE side? And if that could happen, could the center start to wobble to the NE? I'm new to Tropical storms, just trying to get a good idea in my head of the wind fields is all.

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Think we can call this one dead. Seems like the circulation moved inland and has since weakened/dissipated.

Just because you can't see the center on Infrared imagery does not mean the center has dissipated. There is still some ovious low level turning just offshore and to the east of the latest convective burst. Yes Helene is struggling but it remains a TC for the time being.

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I see a lot of mid level turning and some week low level turning right off the coast. maybe its not dissipated but it dont think it gets any stronger than it is now / was earlier.

I think thats a reasonable forecast given that the mid-level circulation is detached and inland from the low-level reflection. This type of vertical displacement does not favor much if any development before landfall.

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