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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I see some circulation in the tropical wave at the AOI east of the islands. what is the opinion as to future development of this wave?
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TD5 looks more SUBtropical today.
Which will win... the LLC or the MLC ?
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Quoting IKE:
Convection has died again with 93L. I doubt they upgrade this mess. I'll be glad when it's history, which it will be shortly with the trough advancing toward it....you can see it now in the upper left hand portion of the images...moving toward 93L...



I don't know why they wouldn't. The COC is surrounded by t'storms. This is the best it's ever looked.
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Can't believe they are calling this swirl of cloud TD5? There is only a broad area of clouds. Trying to stretch and call anything a name in order to say they were right about a BUSY season that so far has had nothing but dry air
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Quoting Cotillion:
'The number of people confirmed to have died after massive landslides in north-western China has risen to 1,117, with 627 others missing, officials say.

Hopes of finding survivors are fading and rescuers are turning their efforts to recovering bodies and preventing outbreaks of disease.

Large areas in Zhouqu county, Gansu province, were enveloped by landslides triggered by rain on Saturday night.

Rain is forecast for later this week, prompting fears of further landslides.'

Link


ummmm who cares???
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Quoting nrtiwlnvragn:


From the latest TD5 discussion

A MEAN CENTER OF THE OVERALL SYSTEM RATHER THAN A WIND CENTER WAS USED FOR THE ADVISORY POSITION.
Ok, What does that mean?
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117. IKE
Convection has died again with 93L. I doubt they upgrade this mess. I'll be glad when it's history, which it will be shortly with the trough advancing toward it....you can see it now in the upper left hand portion of the images...moving toward 93L...



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What I think is happening, is that the large blow-up of convection east of Sarasota, is where a new LLC is forming, or has formed. Additionally, I suspect the exact direction and speed of this new LLC is yet to be determined...

could finally have "become" tropical...and now, is ready for some interesting cyclogenesis. If there is no real LLC..then its' just gonna be a mess. However......

buwahahahaaahahaaaaaaa
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Quoting MiamiHurricanes09:
Ok, well it looks like he put it right where it is supposed to be.
I was probably mistaken then.
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Good morning all! Thanks Dr. Masters for the update! Is there any chance of this storm stalling off the coast and heading more west? As in the upper Texas Coast(Galveston)? Thanks for any input!
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It wouldn't surprise me to see a center reformation closer to the strongest convection with 05L...
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Quoting PensacolaDoug:
Dr Masters refered to the storms in NOLA as "outer" bands. I don't think he gave it more than a passing glance.

I don't think he did either....
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Quoting scott39:
Do you agree with those current cordinates? Looks suspicious to me!


From the latest TD5 discussion

A MEAN CENTER OF THE OVERALL SYSTEM RATHER THAN A WIND CENTER WAS USED FOR THE ADVISORY POSITION.
Member Since: September 23, 2005 Posts: 14 Comments: 11165
110. IKE
Quoting scott39:
Do you agree with those current cordinates? Looks suspicious to me!


I see a spin there...for what it's worth.

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Quoting cyclonekid:
Which would mean that the NHC would have to issue a Special Advisory or a full advisory on TD 06L at 5pm EDT, right?
The T-numbers qualify for that of a 30mph TD, they may do it, I would.

Be back later.
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TD 5 is a hot mess as chelsea lately would say! what a bummer! I doubt it will even become a tropical storm! Its just to broad and doesnt have enough time to tightn up its circulation, good rains for the northern gulf though. Also a new center may be forming further east. It wouldnt suprise me if this would allow for a Alabama or extreme western FL panhandle landfall! not that is would be much of a landfall anyway. More like a rainfall!
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Quoting PensacolaDoug:
Dr Masters refered to the storms in NOLA as "outer" bands. I don't think he gave it more than a passing glance.


I guess the Upper Level Low (ULL) has rain Bands Now.

Awesome, don't want to outshine his post yesterday.
Member Since: August 11, 2008 Posts: 0 Comments: 2315
Quoting DestinDome:
I detected humor about where the COC was.
Ok, well it looks like he put it right where it is supposed to be.
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Quoting MiamiHurricanes09:
That's right about where I see it.
Which would mean that the NHC would have to issue a Special Advisory or a full advisory on TD 06L at 5pm EDT, right?
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I officially hate this season.
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Quoting nola70119:


Levees will be OK, but if the flood gates at the outflow canals have to be closed there could be local flooding inside the levees.


Thanks - *sigh* always happier when I don't have to be worried 'bout you folks. though I'm still quite concerned how your shoreline will be affected -OIL & dispersants
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Quoting MiamiHurricanes09:
What's funny?
I detected humor about where the COC was.
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.
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Dr Masters refered to the storms in NOLA as "outer" bands. I don't think he gave it more than a passing glance.
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Quoting cyclonekid:
MH09...

That's right about where I see it.
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Quoting cyclonekid:
MH09...

LOL!
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Quoting claire4385:


O man...compared to what we've been having. I would run around in my backyard au natural LOL


my thoughts exactly -- specially when the AC went Kaput for the week
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Barely any lower convergence or upper divergence associated with PGI25L.
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89. Its 5 O'clock somewhere Haha.
Member Since: September 6, 2009 Posts: 2 Comments: 3720
MH09...

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Quoting IKE:
Coordinates of TD5.....

27.8N.
86.8W.


Coordinates of buoy 42039.....

28.8N.
86.0W.

Or about 60 miles NE of the "coc" of TD5.........


5-day plot - Wind Direction Wind Direction (WDIR): E ( 80 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 11.7 kts
5-day plot - Wind Gust Wind Gust (GST): 13.6 kts

5-day plot - Wave Height Wave Height (WVHT): 4.9 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 7 sec
5-day plot - Average Period Average Period (APD): 5.1 sec
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.85 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): +0.02 in ( Rising )

5-day plot - Air Temperature Air Temperature (ATMP): 79.0 °F
5-day plot - Water Temperature Water Temperature (WTMP): 86.9 °F
5-day plot - Dew Point Dew Point (DEWP): 78.3 °F
5-day plot - Heat Index Heat Index (HEAT): 83.5 °F
Do you agree with those current cordinates? Looks suspicious to me!
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Quoting unf97:
Good morning everyone.

Thanks Dr. Masters with the update!

TD5 likely to be a huge rain maker the remaining of this week across the Northern Gulf Coast.


We'd sure love to see some of that rain drift over a little farther Westward. Nevertheless, I saw somebody mention Allison on here earlier this morning, and with the slow movement and the looping track some of the models are showing, this is reminiscent of that storm. Nobody wants an Allison-like scenario! Hopefully that won't happen. Maybe too much dry air for that to occur, even if the system does go slow and loop?
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Morning again.

From the now defunct blog....

3913. BahaHurican 11:25 AM EDT on August 11, 2010
Top of the mornin' to ya....


Quoting wayfaringstranger:
I had posted yday that TD5 would have to really step it up in the next 24 hrs and that last night was critical.

Seems like the storms prefer the daylight this year.


I've been saying for weeks that there seems to be some inversion of normal patterns, so that storms seem at their best in the early afternoon and at their worst in the early morning, quite the opposite of what is expected. I'm rather curious as to why that is happening....

Quoting BahaHurican:


Link


Quoting KanKunKid:
OK!

1 Part Blackberry Schnapps
2 Part Vodka (Stolli)
1 Part Pineapple juice
2 Part "Fizz" water (Soda water)
1/2 Grenadine

Mix, pour over ice and spritz with fresh lime.

"The FizzleBerry"
Official drink of the (early) hurricane season..
I'll make up a new one for the first Cat one..
Meanwhile, here's looking at you, kid!
Dude.... it's 11:30 a.m..... 10:30 where u are..... LOL a bit early, yeah? Or is that permission to start "brunch" a bit early.... lol

3929. BahaHurican 11:37 AM EDT on August 11, 2010
Quoting Mixed:
hey guys I have been on this site for a while now in background shame to say but i find the site to be very informative, so i just signed up, I am from St. Lucia in the lesser antilles which looks like it could get a bit stormy later, well it has been for a couple days now heavy lightning, thunder and moderate rain. Its calm now but it looks like it will get worst tonight. Anyways good to be here......


Welcome to the blog. Always good to see another Caribbean blogger. Looks like u guys are going to get some wx from that Twave that's about 400-500 miles E of u.....

----------------------------

BTW, KanKunKid, did u ever get something worked out for image posting? I got on the blog the other night [I guess] after u had gone off...



Member Since: October 25, 2005 Posts: 19 Comments: 22101
Quoting Tropicaddict:


Agreed...same here in Pass Christian. My husband in out cutting the grass as we speak in case we get tons of rain that prevents him from cutting it for a week or so.


Mine needs cutting as well, but by the time I get in from work it is pouring. Looks like it will be awhile for I can chop it down.
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Quoting unf97:


I was wondering the very same thing. If you observe satellite imagery, there seems to be an appearance of a spin about 100 miles due west of Sarasota. There is considerable convection flaring up in that vicinity as well. A very strange system being very elongated and broad. What gives this season uh?


geeze, hate for my neighborhood to be the incubator for any potential trouble maker : ( going for a wave check in a few -- I'll have some words w/the powersthatbe.... perhaps I can get a good connection from the shoreline ; )
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Quoting surfmom:
are NOLA's Levees okay with this amount of rain? or will that be a concern?



No Problem. The question about 8 or more inches of rain is never the levees - it is abouut the pumping stations. Thank you for the concern.
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been watching the visible floater for a while...I just don't see a "center"....this thing is a mess!
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Quoting GeauxGirl:
biloxidaisy said:

"Not me! Where I am in Biloxi (St. Martin) my yard is saturated still from the nearly daily thunderstorms. You can't walk in the backyard without squishing up mud."

Y'all get way more rainfall on the coast than we do further north(Hattiesburg). My pond is very low, about 6 foot down from the spring level. :(

That said, hope you miss the worst of it. Just send it my way!! ;)


I would gladly send it your way! :)
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Area east of the islands, not much at the surface


Member Since: September 23, 2005 Posts: 14 Comments: 11165
Quoting surfmom:
are NOLA's Levees okay with this amount of rain? or will that be a concern?



Levees will be OK, but if the flood gates at the outflow canals have to be closed there could be local flooding inside the levees.
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Hi, I'm new here but peruse the blog throughout each hurricane season. I thought I would ask a question that has been bugging me, forgive my ignorance:

I have always associated "lows" with humidity and rains and "highs" with dry air. How is an "upper level low" different from your average low pressure system? I am reading that the upper level low in the gulf is feeding the depression with dry air, hampering it's development.

I guess I am looking for a layman's definition of an upper level low.

Thanks!
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Quoting twhcracker:
i am hoping for a blustery cool drizly day! would that be awesome or what?!


O man...compared to what we've been having. I would run around in my backyard au natural LOL
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Almost there...06L.

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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.

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