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Atlantic Tropical Action 2013


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Oh, yeah, I've known about it since then as well. Just wanted to post the news story from NOAA released today.

Should be interesting to see how it performs. Maybe we can actually view a run of the model without laughing at it.

 

 

Might not be perfect quite yet..

 

DORIAN91L.2013072906.fsct.png

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Isn't there a weak, low-amplitude CCKW near 135°W (enhanced convection and anomalous 850-mb westerlies) in the EPAC at this time? That could be what the GFS is showing in the MDR by 05 August. This meshes well with the ECMWF projection that the resuscitated, low-amplitude MJO signal will head toward Phase 2 in about one and a half week. This trend might, if I am reading the signs correctly, point to another Cape Verde TC genesis event on or shortly after--i.e., within five days of--05 August. Perhaps HM may feel free to chime in here.

The 00Z ECMWF, for once, shows long-range development while the 00Z GFS does not. By day 10, the ECMWF shows a low developing in the W African monsoon south of the Cape Verde islands--a development that is well timed with the MJO's progression into Phase 2. So the ECMWF may well be picking up the signal for the pattern shift to a more-favorable regime for TC genesis in the MDR.

 

76wo.png

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The 00Z ECMWF, for once, shows long-range development while the 00Z GFS does not. By day 10, the ECMWF shows a low developing in the W African monsoon south of the Cape Verde islands--a development that is well timed with the MJO's progression into Phase 2. So the ECMWF may well be picking up the signal for the pattern shift to a more-favorable regime for TC genesis in the MDR.

 

76wo.png

I have been watching the Euro for the slight chance the mid level trough and associated remnant surface trough might get left over the Northeast Gulf.  Suggestions of that on last 3 Euro runs.  GFS has trough in similar position, but nowhere deep enough to possible cutoff and retrograde.  Only chance of action close to home inside of the next two weeks I can see, and not a very good chance.  Op GFS has a wave leaving Africa a couple days behind a moisture starved wave in 15 days, maybe the first wave could be the sacrifice to the SAL monster.  Scraping the barrel of desperation, not GFS 2 week phantasy storms.  Two week fantasy waves.

 

New Euro just in, still offers faintest glimmer of non-tropical origin hope.

post-138-0-10942200-1375211043_thumb.gif

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I have been watching the Euro for the slight chance the mid level trough and associated remnant surface trough might get left over the Northeast Gulf.  Suggestions of that on last 3 Euro runs.  GFS has trough in similar position, but nowhere deep enough to possible cutoff and retrograde.  Only chance of action close to home inside of the next two weeks I can see, and not a very good chance.  Op GFS has a wave leaving Africa a couple days behind a moisture starved wave in 15 days, maybe the first wave could be the sacrifice to the SAL monster.  Scraping the barrel of desperation, not GFS 2 week phantasy storms.  Two week fantasy waves.

 

New Euro just in, still offers faintest glimmer of non-tropical origin hope.

 

 

You know you're suffering a case of tropical depression when you're posting a slight chance of an Andrea repeat on the 240 h Euro. 

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Not really...

 

(SAL gif)

He said for this year. Not on this date. The image for 2013 in that loop doesn't even capture the latest SAL outbreak since it's from the 25th of July. Not sure why you included the gif.

 

Judging by the pinks showing up on the latest SAL images, this is probably one of the strongest SAL outbreaks so far this year.

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The Sahel has been pretty wet thus far this year- less likely to get those big pulses of dry air coming off Africa. The current event does look to be strong given the current seasonal state over West Africa.

 

I know we are searching for any hope right now- the latest European and GFS 00z are hinting of a PV streamer in the Gulf of Mexico- European developing a nice gyre that tries to go warm-core. Should be something to watch at least. I am also seeing some signs of potential life (not really in models) but in other predictors for some increased Atlantic activity sometime during the 2nd-4th week of August.

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He said for this year. Not on this date. The image for 2013 in that loop doesn't even capture the latest SAL outbreak since it's from the 25th of July. Not sure why you included the gif.

 

Judging by the pinks showing up on the latest SAL images, this is probably one of the strongest SAL outbreaks so far this year.

 

I understand the image from 2013 is not current; I used this same SAL graphic last week when depicting that Dorian was embedded in a relatively dust free environment. My point was in other years (2008-2012) widespread SAL events were observed and relatively common. Sure the magnitude of this event does seem to be on the higher end of the spectrum, but despite its intensity, I don't think this is an uncommon occurrence for this type of the year. 

 

Its like saying a major hurricane is uncommon in the month of September. Sure its a strong magnitude event (and climatologically ~2 happen per year) but its not an unusual occurrence for that time of the year. Saharan Air Layer outbreaks are not uncommon during the month of July and well into August. 

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You know you're suffering a case of tropical depression when you're posting a slight chance of an Andrea repeat on the 240 h Euro. 

 

Another run of the Euro, another old frontal trough developing a low near Florida and heading it WSW towards Mexico.  May not happen, but 5 runs in a row of something non-tropical in the Gulf.  It is possible because it means no rain in my yard, which is consistent with GFS 16 day depiction of a quarter to half an inch total, or a miserably dry first half of August.  But heat potential (3 days ago, my AOML site is a couple of days off) is 60 to 80 kJ/cm^2, off the Mexican coast, and my natural optimism, you may say that I'm a dreamer, but I'm not the only one. 

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The CFSv2 weeklies during the mid to late August time frame are suggesting a bit of an uptick in precip across the Caribbean and Gulf. I suspect this fit with the arrival of the MJO/Kelvin Wave that others have alluded to heading E across the Pacific.

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I understand the image from 2013 is not current; I used this same SAL graphic last week when depicting that Dorian was embedded in a relatively dust free environment. My point was in other years (2008-2012) widespread SAL events were observed and relatively common. Sure the magnitude of this event does seem to be on the higher end of the spectrum, but despite its intensity, I don't think this is an uncommon occurrence for this type of the year. 

 

Its like saying a major hurricane is uncommon in the month of September. Sure its a strong magnitude event (and climatologically ~2 happen per year) but its not an unusual occurrence for that time of the year. Saharan Air Layer outbreaks are not uncommon during the month of July and well into August. 

You still seem to be missing the point. Nobody is talking about the time of year here. We all know that these events can happen during this time of year. The point was it hasn't happened so far this year. SAL events so far this year have been minimal in comparison to our latest outbreak. Hence, this event is "uncommon for this year".

 

WestAfrica.A2013211.1140.2km.jpg

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12z CMC seriously has something wrong with it. This is about as bad of a run I have ever seen. Hour 138 is where it starts.

http://www.tropicaltidbits.com/analysis/models/gem/2013073112/gem_mslp_pcpn_atl.html

Edit: Nevermind, only the MSLP and Precipitation Rate show that horrid run. Everything else is normal.

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12z CMC seriously has something wrong with it. This is about as bad of a run I have ever seen. Hour 138 is where it starts.

http://www.tropicaltidbits.com/analysis/models/gem/2013073112/gem_mslp_pcpn_atl.html

Edit: Nevermind, only the MSLP and Precipitation Rate show that horrid run. Everything else is normal.

 

Pretty sure there was just a plotting issue or data corruption issue on that website.  The run itself was fine, even the mslp field e.g. here: http://moe.met.fsu.edu/cgi-bin/cmctc2.cgi?time=2013073112&field=Sea+Level+Pressure&hour=Animation

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Pretty sure there was just a plotting issue or data corruption issue on that website. The run itself was fine, even the mslp field e.g. here: http://moe.met.fsu.edu/cgi-bin/cmctc2.cgi?time=2013073112&field=Sea+Level+Pressure&hour=Animation

Yep a plotting issue. Those two storms at the end of the run are actually in the WPAC.

http://www.tropicaltidbits.com/analysis/models/gem/2013073112/gem_mslp_wind_wpac_41.png

http://www.tropicaltidbits.com/analysis/models/gem/2013073112/gem_mslp_pcpn_atl_40.png

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You still seem to be missing the point. Nobody is talking about the time of year here. We all know that these events can happen during this time of year. The point was it hasn't happened so far this year. SAL events so far this year have been minimal in comparison to our latest outbreak. Hence, this event is "uncommon for this year".

 

WestAfrica.A2013211.1140.2km.jpg

 

That is an impressive MODIS image. And while I agree that SAL has ben below normal recently (last 10 days or so), there were plenty of SAL outbreaks in the earlier portion of this month that are on the same scale as this recent SAL intrusion.

 

e.g. July 8th

 

257hfye.jpg

 

Compared to now

 

splitE.jpg

 

In the end, this is a silly thing to be arguing over... I agree with Mike that the overall pattern with increased rainfall over the Sahel should favor less dust coming off the African continent overall, although it obviously won't prevent it entirely, even larger outbreaks. 

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On a semi-unrelated note, as someone who remembers when Dr. Gray used Sahel rainfall in his mid 1990s seasonal TC forecasts, I believe I know may have a hazy (pun intended) understanding as to why Sahel rainfall had a reasonably strong correlation to TC activity.  Why it is not as strong a factor, apparently, and no longer used since the warm AMO, that I still don't know.

 

OKPowdah's QBO discussions have aided me in understanding why those same 1990s seasonal forecasts also used QBO phase.

 

Back to SAL and general depression in the tropics, the 0Z North American ensembles means and spreads, looks like a single ensemble member might have something approaching the Bahamas in two weeks.  If an ensemble that includes even CMC global ensemble perturbations can't do better than that in 2 weeks, the tropics must truly be dead.

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Since we won't have our first hurricane of the season through the first week of August, I put

together the first hurricane dates post August 7th going back to 1995.

 

8-22-11

8-17-09

8-16-07

9-11-02

9-09-01

8-21-99

8-22-98

 

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