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Atlantic Tropical Action 2013


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We'll see if future runs of the GFS hold serve or move back to a more consolidated system

instead of the strung out solutions after the 6z run.

 

18z

 

attachicon.gifgfs_atlantic_075_850_vort_ht.gif

 

 

6z

 

attachicon.gifgfs_atlantic_081_850_vort_ht.gif

Just looking at hour 3 ( 21Z, about 90 minutes ago) 850 mb, with almost no low level vorticity, and very weak 500 mb mid level vorticity where the main blobbage of 92L was rocking and rolling, I am thinking, strictly as an amateur hobbyist, that the GFS somehow didn't initialize well or get a good start.

 

 

I was going to compare it to CIMSS vorticity at different levels, but F5 not getting me off 14 August 0600UTC.  But I think somehow the GFS initialized too weak.  IMHO.

 

 

FWIW, 12Z FIM9 is a touch weaker, a 35 to 40 knot storm, but almost identical path in SE Louisiana, as previous couple of 15 km FIM runs.

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Just looking at hour 3 ( 21Z, about 90 minutes ago) 850 mb, with almost no low level vorticity, and very weak 500 mb mid level vorticity where the main blobbage of 92L was rocking and rolling, I am thinking, strictly as an amateur hobbyist, that the GFS somehow didn't initialize well or get a good start.

 

 

I was going to compare it to CIMSS vorticity at different levels, but F5 not getting me off 14 August 0600UTC.  But I think somehow the GFS initialized too weak.  IMHO.

 

 

FWIW, 12Z FIM9 is a touch weaker, a 35 to 40 knot storm, but almost identical path in SE Louisiana, as previous couple of 15 km FIM runs.

Site was down due to hardware failure for several hours. It was reestablished about an hour ago. Hopefully it will get the most recent data for 21Z

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Just looking at hour 3 ( 21Z, about 90 minutes ago) 850 mb, with almost no low level vorticity, and very weak 500 mb mid level vorticity where the main blobbage of 92L was rocking and rolling, I am thinking, strictly as an amateur hobbyist, that the GFS somehow didn't initialize well or get a good start.

 

 

I was going to compare it to CIMSS vorticity at different levels, but F5 not getting me off 14 August 0600UTC.  But I think somehow the GFS initialized too weak.  IMHO.

 

 

FWIW, 12Z FIM9 is a touch weaker, a 35 to 40 knot storm, but almost identical path in SE Louisiana, as previous couple of 15 km FIM runs.

 

It tightens up right before crossing the Yucatan coast. But today's runs of the GFS looked more elongated with

the pressure field like the Euro has been showing once it emerges over the Gulf.

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I just don't get it guys. What is with this year? It seems that if the systems that have managed to develop lately have died from dry air and or windshear. Reminds me of last year and the year before that. What is going on?

typical climo up to mid August really.  The reason you don't have many strong systems through July is because of cooler ocean temps relative to late season, more vigorous mid-latitude troughs causing shear in the MDR, and SAL (dry air) intrusions into the Atlantic.  Those factors wane as we head into August.  Be patient.  The season will start soon enough.  Year-to-date ACE shows we should be at 14, and we are at 7.  Yearly normal is 104.  So, we are barely 1/8th of the way through the season.

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I kinda surprised how high the probabilities have gotten with 92L. Its quite evident via ASCAT that this system is not close to attaining a llc, and the mid-level vortex is completely disjointed from the best low-level vorticity. Thus, it shouldn't be surprising to see convection collapse tonight very reminiscent of Dorian in the few few days after its initial dissipation to a remnant low. 

 

The same basic problem I illustrated last night is still there. There is a upper level +PV vortex that is centered over the Central GOM. It has been eroded somewhat by diabatic outflow from daytime convection over the southeast, as well as the impinging outflow from 92L, but the feature is still quite evident, and is now beginning to restrict the outflow of 92L. Whats likely to happen is that this upper-level feature will continue to slowly break down, but not before disrupting the well defined outflow pattern associated with the mid-level vortex of 92L. This same feature is also inducing a mid-level weakness (lower heights) to the north of 92L in which the mid-level component of the circulation is likely to continue feeding northward, separate from the best low-level vorticity, which could track further westward. This is what is resulting in the very disjointed and poorly organized nature of both the ECMWF and GFS, and both models attempt to spin up a new low-level vortex in association with this mid-level energy much further north before landfall along the AL/MS coastline. 

 

Overall, its still not a pattern that favors a very strong TC (if we even get a TC) and I'd be hesitant to think of seeing anything stronger than a weak TS before landfall within 72 hours in the northern GOM. There will have to be some pretty radical changes in the next 24 hours for a different outcome to become more likely. 

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This might be more interesting down the road...

 

Edit: lol

 

THE DEPRESSION IS CURRENTLY IN AN ENVIRONMENT THAT IS CONDUCIVE FOR
STRENGTHENING...CHARACTERIZED BY LOW WIND SHEAR...WARM SSTS...AND A
MOIST AIR MASS. THIS ENVIRONMENT...HOWEVER...WILL BECOME A LITTLE
LESS FAVORABLE IN A FEW DAYS WHEN THE CYCLONE IS EXPECTED TO REACH
SLIGHTLY COOLER SSTS AND A MORE STABLE ENVIRONMENT. IN ADDITION...
THE DEPRESSION IS LIKELY TO BE CUT OFF FROM ITS DEEP MOISTURE
SOURCE TO THE SOUTH IN ABOUT 3 DAYS. THEREFORE...MODEST
STRENGTHENING IS INDICATED IN THE OFFICIAL FORECAST THROUGH THE
FIRST 48 HOURS WITH SOME WEAKENING BY THE END OF THE FORECAST
PERIOD. THIS FORECAST IS VERY NEAR THE INTENSITY CONSENSUS.

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Phil 

92L is the Caribbean system.

 

 

As soon as I could see lower clouds through cirrus, even though IR tops were still kind of cold, I was kind of hoping I was wrong, but the convection collapsed on 92L just as it seems to do so often late in the afternoon on interesting systems.

 

Bit late, if I remember correctly about D-Max and D-Min, but yup, it collapsed.

 

93L formed a little earlier than I would have preferred, but what I said before about the 500 mb pattern about 2 days ago, it has a better chance than most of being a long tracker.  If it doesn't get too strong, could be below 20N in 6 days.  It still will probably fish being that far East, but at least it has a chance.

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Phil 

92L is the Caribbean system.

 

 

As soon as I could see lower clouds through cirrus, even though IR tops were still kind of cold, I was kind of hoping I was wrong, but the convection collapsed on 92L just as it seems to do so often late in the afternoon on interesting systems.

 

Bit late, if I remember correctly about D-Max and D-Min, but yup, it collapsed.

 

93L formed a little earlier than I would have preferred, but what I said before about the 500 mb pattern about 2 days ago, it has a better chance than most of being a long tracker.  If it doesn't get to strong, could be below 20N in 6 days.  It still will probably fish being that far East, but at least it has a chance.

 

The problem is the environment thats expected to develop beyond 40W (both dynamically and thermodynamically) is absolute trash. TD5 (future Erin) is basically Dorian 2.0. It will likely be another case where the upper level flow is slower than the low-level flow and we will watch a nice looking tropical cyclone turn into a sheared out piece of crap. 

 

Sorry I've been getting 92L and 93L mixed up all day.

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HWRF has backed off on intensity. Now no model has more than a pretty weak low. Also the track consensus has shifted more to the LA coast area. Meh.

 

Of either system, I'd be more concerned with TD - 5. In the long run, a moderate tropical storm moving west under a building ridge of high pressure towards the Bahamas in mid-late August could always spell trouble.

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