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 IKE:


Downcasting...lol.

Here btwntx08.....look at the convection die off in this loop....Link

Listen to weatherguy03's take on 93L...Link
Ike, that doesn't mean I don't think there's still a window of opportunity for 93L. But I do think it's best chance to strengthen is gone. Levi may be right about another window on the weekend, but we shall see about that....
Member Since: October 25, 2005 Posts: 19 Comments: 20742
175. IKE
Quoting BahaHurican:
Just outta curiousity, Ike, r u and DestinJeff related?

LOL





Yup...we're both panhandlers.
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173. DDR
Over 14 inhes here in 11 days
I'm out.
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MScasinojunkie, congrats! You just won the prize for most ignorant post of the day!
Member Since: June 27, 2010 Posts: 0 Comments: 760
Quoting nola70119:


May Flood, I think it was 93, but I don't remember.......20 people died, Canal Street was flooded to the windows of the taxis, etc. Its a famous flood....just from t'storms training from the SW over Houma.


1995

Two day totals from NWS acrchives indicated the total rainfall which fell:

New Orleans (International Airport) 9.67" New Orleans (Lakefront Airport) 15.44" Harahan 14.88" Kenner 17.11" Metairie 19.39" New Orleans East 20.20"

Slidell 19.09" Mandeville 23.66" Madisonville 22.86" Covington 21.00" Lacombe 34.76" Hammond 8.54"
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93L ate away the SAL. SAL's almost non-existent in the Atlantic.
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Quoting DDR:

OH...in 93
Thought you had that today lol


LOL
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165. SLU
*yawn*



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May 8th 1995 Louisiana Flood
From Wikipedia, the free encyclopedia
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Contents
[hide]

* 1 Mitigation work prompted by the flooding
* 2 See also
* 3 External links

The May 8th and 9th 1995 New Orleans Flood struck the New Orleans metropolitan area, shutting down the city for two days. It was a two-event phenomenon. Areas south of the lake began receiving tremendous amounts of rain at approximately 5:30 p.m. on May 7th, continuing into the early morning hours of May 8th. The flooding began on the Southshore, Jefferson Parish and Orleans Parish, including the cities of New Orleans, Metairie, Kenner, River Ridge, and Harahan, on May 8. During a short period of twelve hours, some areas received twenty inches of rainfall. The next day, the Northshore of Lake Pontchartrain, including Slidell, Covington, etc. received similar amounts of rain and flooding. Two day totals from NWS acrchives indicated the total rainfall which fell:

New Orleans (International Airport) 9.67" New Orleans (Lakefront Airport) 15.44" Harahan 14.88" Kenner 17.11" Metairie 19.39" New Orleans East 20.20"

Slidell 19.09" Mandeville 23.66" Madisonville 22.86" Covington 21.00" Lacombe 34.76" Hammond 8.54"

Some have compared this to the great November 1979 Louisiana Flood, or the more recent November 7 - 8 1989 Louisiana Flood, though the May 8th Flood was more extensive and costlier than both combined. It was the worst flooding the city had experienced between hurricanes Betsy in 1965 and Katrina in 2005. There has been no comparable recorded flood in New Orleans caused by rain alone. (Rain also caused significant street flooding in New Orleans on Good Friday of 1927 and May 3, 1978.)


Six people died as a result of the flooding.
as a result of the flooding. The city of New Orleans suffered $360 million in damages, and the damage of the surrounding areas put that total above $1 billion. Some 56,000 homes were damaged in 12 Parishes. Thousands of cars were flooded. 14,600 homes and apartments were flooded in Jefferson Parish.

The cause of the massive rain fall totals was a stalled out frontal system from the northwest. It produced a train effect, in which rain and/or thunderstorms continued to form over the same area. Pumping stations were overwhelmed and could not pump out the water into Lake Pontchartrain. The pumping stations are only rated to pump one inch per hour maximum.
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Quoting scott39:
clever


If you don't quote him I can't see him.... :)
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162. DDR
Quoting nola70119:


May Flood, I think it was 93, but I don't remember.......20 people died, Canal Street was flooded to the windows of the taxis, etc. Its a famous flood....just from t'storms training from the SW over Houma.

OH...in 93
Thought you had that today lol
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Just outta curiousity, Ike, r u and DestinJeff related?

LOL



Member Since: October 25, 2005 Posts: 19 Comments: 20742
160. DDR
The itcz refuses to leave me alone
Floods all over and its raining again
Just had a quick fire 2.5 inches
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Quoting DDR:

You got 15 inches in 8 hrs time?


May Flood, I think it was 93, but I don't remember.......20 people died, Canal Street was flooded to the windows of the taxis, etc. Its a famous flood....just from t'storms training from the SW over Houma.
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Still amazes me to see the lack of patience on this blog with a few of the bloggers.
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Quoting IKE:


You mean Aug-bust?
clever
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FWIW Ike, I don't see you as a downcaster. You were on of the few along with Patrap that was following 95L and not downcasting it.
Member Since: June 27, 2010 Posts: 0 Comments: 760
152. DDR
Quoting nola70119:
Saw 15 inches of rain in 8 hours here in New Orleans.......May flood.

You got 15 inches in 8 hrs time?
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Quoting IKE:


You mean Aug-bust?


Eye-gust
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12z NAM @ 84 hours


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Quoting StSimonsIslandGAGuy:
I think Dr. Masters gave an excellent summary of TD 5. Those are outer bands of showers hitting southeast Louisiana.


Go put a shirt on. j/k
Member Since: August 11, 2008 Posts: 0 Comments: 2315
If a center can consolidate in the convection just off the Florida coast, it'd have much more time over water than if it keeps the broad "mean" center.
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146. IKE
Quoting BahaHurican:
btwn, u gotta toughen up, man... lol


Downcasting...lol.

Here btwntx08.....look at the convection die off in this loop....Link

Listen to weatherguy03's take on 93L...Link
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Quoting Kristina40:


I suppose people that dislike human suffering and death brought on by natural disasters.


+1

v/r

Jon
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Interesting moisture surge depicted by 12Z NAM into the C to Norther Caribbean:



Something to watch this weekend if GFS and other models increase moisture levels in the southern to central Caribbean Sea as well later in the period.
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Afternoon,
Looking eastward for a moment, SAL is very low.

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140. IKE
Quoting DestinJeff:
TD5 is ushering some rather viscious sunshine here in NW FL. I think the UV Index advisory trumps the TS Warning at this point.

Another instance of a sputtering cyclone for 2010.

The Ides of August are upon us in just a few days.


You mean Aug-bust?
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Quoting btwntx08:
man i just had it with ike he keeps down casting and i just had it the t numbers for 93L are 1.5 which would be a td :P
btwn, u gotta toughen up, man... lol
Member Since: October 25, 2005 Posts: 19 Comments: 20742
Saw 15 inches of rain in 8 hours here in New Orleans.......May flood.
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that flare up of conv. by florida could that be a new center trying to form?
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Quoting palmasdelrio:
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?


its trajectory is one to bear watching.
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this is the broadest area of low pressure I think I have ever seen
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Quoting MScasinojunkie:


ummmm who cares???


I suppose people that dislike human suffering and death brought on by natural disasters.
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8. Orcasystems 10:28 AM EST on August 11, 2010 Hide this comment.
From Jeff's post: This will allow the storm to dump very heavy rains in excess of eight inches in isolated regions.

I cannot even imagine 8" of rain :(


I have seen it and it aint a purty sight. Camille did it to Nelson Co, VA back in 69 and I don't want to see that kind of mess ever again. Only reason I'm not wish-casting this one to here. We need rain but not a flood.
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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.