Tropical Depression Five a heavy rain threat; the smoke clears in Moscow

By: Dr. Jeff Masters , 3:23 PM GMT on August 11, 2010

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Tropical Depression Five is currently weak and disorganized, but it has the potential to organize into a potent rain-maker that may bring extremely heavy rains to Louisiana, Mississippi, Alabama, and Georgia over the next four days. Outer rain bands from TD 5 are already affecting the New Orleans region, where as much as two inches of rain has fallen in isolated regions. TD 5 has only limited heavy thunderstorm activity at present, thanks to an infusion of dry air early this morning from an upper-level low pressure system over the Gulf of Mexico. However, TD 5 is steadily recovering from this blow, and water vapor imagery shows the atmosphere is moistening in the eastern Gulf of Mexico as TD 5 builds more heavy thunderstorms. Wind shear is currently a moderate 10 - 15 knots over TD 5, and water temperatures are very warm, 31°C. The Hurricane Hunters have left TD 5, and a new aircraft is scheduled to arrive this afternoon.


Figure 1. Morning radar image of TD Five from the New Orleans radar.

Forecast for TD 5
The latest SHIPS model forecast predicts that wind shear will drop to the low range, 5 - 10 knots, by tonight, and remain low for the remainder of TD 5's life. The main hindrance to development will be the current large, disorganized nature of the storm's circulation. Without a tight, well-defined center of circulation, it will take time for the storm to intensify, and I don't expect TD 5 will have time to become more than a 50 mph tropical storm. NHC is giving TD 5 just a 2% chance of reaching hurricane strength. The main threat from TD 5 will be rainfall. This is a slow-moving storm, and the steering currents pushing the storm towards the coast are expected to weaken Thursday and Friday. TD 5 will likely slow to a crawl on Thursday and Friday, moving at just 3 - 5 mph. This will allow the storm to dump very heavy rains in excess of eight inches in isolated regions.

93L
There is not much new to report on the tropical wave (Invest 93) in the middle Atlantic Ocean that has been close to tropical depression status for three days now. The disturbance has a well-defined surface circulation, but only a limited amount of heavy thunderstorm activity, thanks to dry air aloft and wind shear of 10 - 20 knots. Wind shear is expected to stay in the moderate range, 10 - 20 knots, over the next three days, which is low enough that 93L could become a tropical depression at any time during that period. NHC is giving 93L a 70% chance of developing into a tropical depression by Friday morning. The GFS, GFDL, and HWRF models predict 93L will develop, and the GFDL forecasts that the storm will become a hurricane. A strong trough of low pressure moving across the central Atlantic is recurving 93L to the north, and the system should only be a concern to shipping interests. None of the reliable computer models are forecasting tropical cyclone development in the Atlantic over the next seven days, other than for 93L.

Moscow's air clears, but it is still extraordinarily hot
A thunderstorm blew through Moscow early this morning, bringing a little rain and a very welcome shift of wind direction. The wind shift freed the city from the persistent wild fire smoke that had plagued the city for seven straight days. Temperatures at Moscow's Domodedovo airport hit 35°C (95°F) today, the 29th day in row that temperatures have exceeded 30°C (86°F) in Moscow. The average high temperature for August 11 is 21°C (69°F). Moscow's high temperatures have averaged 15°C (27°F) above average for the first eleven days of August--a truly extraordinary anomaly. There is some modest relief in sight--the latest forecast for Moscow calls for high temperatures of 30 - 31° (86 - 88°F) Thursday through Sunday. This is still 20°F above normal, but will be a welcome change from the extreme heat of the past two weeks. Long range forecasts from the ECMWF and GFS models show no major change to the ridge of high pressure locked in over Russia, for at least the next seven days. However, both models suggest that a trough of low pressure may be able to erode the ridge significantly 8 - 10 days from now, bringing cooler temperatures of 5°C (8°F) above average.

Next update
I'll have an update this afternoon between 3 - 4 pm EDT.

Jeff Masters

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Quoting StormW:
Levi.


Storm.
Member Since: November 24, 2005 Posts: 635 Comments: 26647
It would be nice if the trolls at least typed in recognizable English. How can I be outraged when I can't understand what they write?
Member Since: June 27, 2010 Posts: 0 Comments: 760
Quoting twhcracker:


how do you know they didnt deliberate spill oil in order to create killer blood sucking mutant ridley turtles that will start seething and roiling around in the gom dispersing all the hurricanes!


Kemp's Ridley turtles are already critically endangered. The oil will just kill them further. It is unfortunately not a science fiction movie out there.
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Quoting stormlvr:


Yes. Hopefully some will see that it is to early to judge the season. What you think you see is not necessarily what you are going to get!
That plus Levi's latest efforts are reminding me that the Bahamas usually gets its worst between the end of August and the beginning of October. I'm not letting down my guard yet...

Quoting IKE:


It's almost to the point of looking at the last 10 days of August for a chance of something significant, affecting anyone, in the Atlantic.

I know I'll get hammered from the blogger in Brownsville over what I'm saying, but I don't see much the next 7-10 days.
u and the blogger from brownsville just need 2 agree to disagree.... I'd already mentally set 15 Aug as the earliest we'd see anything major happening. I'm still looking at the area going into the E Antilles, though vorticity seems to have decreased markedly with that in the last 12.

Right now the ULLs still seem to be holding sway, but the SAL is way down. Other indicators are lining up. La nina seasons seem to get going late, but they last for a long long time....
Member Since: October 25, 2005 Posts: 19 Comments: 22081
Quoting fallinstorms:
i think this season is over


We still 2 1/2 months.. My 20KW generac is still not for sale!!!!
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I hope Mother Nature doesn't pull a quikie on us in the Gulf?
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Quoting tkeith:
466. fallinstorms

Just dont send this info to WikiLeaks...


not as good as this one HAHA
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Quoting Patrap:


It went down fine.,thanx.

Hopefully Friday the bad stuff if any will be a scooting out.

many thanks....

lookin' forward to scarfing one down this weekend.
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Member Since: July 3, 2005 Posts: 424 Comments: 128259
Well, dangit, not wishing on my friends further south, but I'm headed outside to do a little raindance. It may not actually rain, but with the current humidity at least I know I'll get wet.
Member Since: September 2, 2008 Posts: 0 Comments: 105
NAEFS 2-week forecast showing cooler temps over Cuba which you can barely see on the right side of the image, and when you see cooler temps in the midst of scorching heat in the tropics on a model, you have to be on the lookout because that means more rainfall which is cooling the temps, and in the tropics that can mean tropical cyclones running through the area.

Member Since: November 24, 2005 Posts: 635 Comments: 26647
Quoting hurricanehanna:
Hey Pat...see any reason for me not to head that way Friday? We'll be in the Garden District area.

How was that Poboy?


It went down fine.,thanx.

Hopefully Friday the bad stuff if any will be a scooting out.
Member Since: July 3, 2005 Posts: 424 Comments: 128259
Hey Pat...see any reason for me not to head that way Friday? We'll be in the Garden District area.

How was that Poboy?
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Quoting Krycek1984:
I know that there has been a lot of analysis concerning a very active season and conditions that are ripe for tropical development. I have enjoyed all of the blogs, especially StormW's, describing why this is.

To play devil's advocate, are there any conditions in place that could hinder tropical development this season? I see a lot of "groupthink" and there must be data supporting a somewhat quiet, or even "average", season.


i still maintain with all the experts calling for a busy season, then if its NOT, then something is wrong.
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Check this out, GFS operational run starting to see the system that's on the ensemble mean, coming off Africa in 7-8 days:

Member Since: November 24, 2005 Posts: 635 Comments: 26647
things look fairly benign over the tropics in the next few days but we need to watch off Africa because the latter part of August and all of September and October look like they're going to be pretty active.
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Quoting DoubleAction:
Radar does not pick up a new coc either, guess it's just a very poorly organized system, although relocations often do occur. Just keeping an eyed out on this one. This might go down as the year of the ULL's.


It will not be the year of the TUTT/ULLs for much longer:

Landsea 2005:
In the North Atlantic, the TUTT first develops in June, strengthens in July and August, and dissipates in September and October. In its climatological position, the trough axis tilts from the central North Atlantic into the Gulf of Mexico as shown for mean August conditions in Fig. 2. Smaller scale (few hundred kilometers) closed circulations - cold lows or TUTT cells - form within the TUTT and move to the south and west along the TUTT axis throughout the summer.
Member Since: August 8, 2006 Posts: 0 Comments: 9132
Organizing a bit more after the latest frame, I don't think it will dissipate.

Photobucket
Member Since: July 1, 2008 Posts: 13 Comments: 7387
Quoting CaicosRetiredSailor:
Hello Baha

Just got home, and I see the blob which I thought you were keeping that way has slipped down here and is dripping on me.
BTW, u should watch Levi's video if u haven't yet. It will give u the heebie jeebies...
Member Since: October 25, 2005 Posts: 19 Comments: 22081
so far except for Alex its all been dry aired to death, sheared to death or ULL'd to death.. will these patterns change?
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Quoting reedzone:


I had enough with you bull, see ya!


what?! the nhc is saying itll die!
Member Since: September 6, 2007 Posts: 0 Comments: 6485
Quoting CaicosRetiredSailor:
Hello Baha

Just got home, and I see the blob which I thought you were keeping that way has slipped down here and is dripping on me.
Hey, we had enough of that yesterday and Monday... today's supposed to be drying out day...
Member Since: October 25, 2005 Posts: 19 Comments: 22081
Quoting Patrap:
..Its a Love Beat..


Gulf Of Mexico - Rainbow Loop


Last Loop Looks like it is trying to form a center.
Member Since: Posts: Comments:
I know that there has been a lot of analysis concerning a very active season and conditions that are ripe for tropical development. I have enjoyed all of the blogs, especially StormW's, describing why this is.

To play devil's advocate, are there any conditions in place that could hinder tropical development this season? I see a lot of "groupthink" and there must be data supporting a somewhat quiet, or even "average", season.
Member Since: Posts: Comments:
Life seems to be still in the Dvorak.

Member Since: July 3, 2005 Posts: 424 Comments: 128259
Quoting IKE:


It's almost to the point of looking at the last 10 days of August for a chance of something significant, affecting anyone, in the Atlantic.

I know I'll get hammered from the blogger in Brownsville over what I'm saying, but I don't see much the next 7-10 days.


We might have something to watch next days as the gfs is showing this guy off Africa but take with a grain of salt until we get higher model support and consistency.
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Ok I'm done with this very messed up system- I'm writing off this td. Rip td5! Just disorganised rains with a breeze. :)
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Radar does not pick up a new coc either, guess it's just a very poorly organized system, although relocations often do occur. Just keeping an eyed out on this one. This might go down as the year of the ULL's.
Member Since: August 13, 2008 Posts: 0 Comments: 159

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.