Pakistan's Katrina; 94L could develop in Gulf of Mexico

By: Dr. Jeff Masters , 3:23 PM GMT on August 10, 2010

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The monsoon season of 2010 continues to generate havoc in Asia, as lingering rains from the latest monsoon low continue to affect hard-hit Pakistan, China, and India. At least 702 are now reported dead and 1,042 are missing in China's Gansu province, due to torrential monsoon rains that triggered a deadly landslide and extreme flooding on Sunday. At least 137 died in floods and landslides in the neighboring Indian state of Kashmir over the weekend, with 500 people missing. Monsoon flooding and landslides have also killed at least 65 people in Afghanistan in the past two weeks. But no country has suffered more than Pakistan, where monsoon floods have destroyed huge portions of the nation's infrastructure and killed at least 1600 people. The number of people affected or needing assistance has been estimated to be as high as 13 million people--8% of the nation's population. The disaster is the worst natural disaster in Pakistan's history, and is rightfully being called "Pakistan's Katrina."


Figure 1. The heavy thunderstorms of a monsoon depression lie over northwestern Pakistan near Islamabad in this visible satellite image taken by NASA's MODIS instrument on July 29, 2010. Image credit: NASA.

Monsoons: a primer
In summer, the sun warms up land areas more strongly than ocean areas. This occurs because wind and ocean turbulence mix the ocean's absorbed heat into a "mixed layer" approximately 50 meters deep, whereas on land, the sun's heat penetrates at a slow rate to a limited depth. Furthermore, due to its molecular properties, water has the ability to absorb more heat than the solid materials that make up land. As a result of this summertime differential heating of land and ocean, a low pressure region featuring rising air develops over land areas. Moisture-laden ocean winds blow towards the low pressure region and are drawn upwards once over land. The rising air expands and cools, condensing its moisture into some of the heaviest rains on Earth--the monsoon. Monsoons operate via the same principle as the familiar summer afternoon sea breeze, but on a grand scale. Each summer, monsoons affect every continent on Earth except Antarctica, and are responsible for life-giving rains that sustain the lives of billions of people. In India, home for over 1.1 billion people, the monsoon provides 80% of the annual rainfall. However, monsoons have their dark side as well--hundreds of people in India and surrounding nations die in an average year in floods and landslides triggered by heavy monsoon rains. The most deadly flooding events usually come from monsoon depressions (also known as monsoon lows.) A monsoon depression is similar to (but larger than) a tropical depression. Both are spinning storms hundreds of kilometers in diameter with sustained winds of 50 - 55 kph (30 - 35 mph), nearly calm winds at their center, and generate very heavy rains. Each summer, approximately 6 - 7 monsoon depressions form over the Bay of Bengal and track westwards across India. Four monsoon depressions originated in the Bay of Bengal in the El Niño-weakened monsoon season of 2009. This year's first monsoon depression formed on July 24, crossed over India, and reached Pakistan on July 27. The rains increased in intensity over the next two days, peaking on July 29 and 30, when a low pressure system that moved across Pakistan from the west enhanced rainfall from the monsoon depression. Over the 3-day period July 28 - 30, torrential rains in excess of 8 inches (203 mm) fell in many regions of northwest Pakistan Rainfall amounts at two stations in the catchment basins of the Jhelum River and Indus River reached 19.49" (495 mm) for the month of July, and 7.56" (192 mm) fell in a single day, July 30, at Tarbela. A second monsoon depression arrived in Pakistan on August 3, and has brought additional heavy rains.

Are the this year's monsoon floods due to global warming?
No single weather event can be attributed to climate change, but a warming climate does load the dice in favor of heavier extreme precipitation events. This occurs because more water vapor can evaporate into a warmer atmosphere, increasing the chances of record heavy downpours. In a study published in Science in 2006, Goswami et al. found that the level of heavy rainfall activity in the monsoon over India had more than doubled in the 50 years since the 1950s, leading to an increased disaster potential from heavy flooding. Moderate and weak rain events decreased over the past 50 years, leaving the total amount of rain deposited by the monsoon roughly constant. The authors commented, "These findings are in tune with model projections and some observations that indicate an increase in heavy rain events and a decrease in weak events under global warming scenarios." We should expect to see an increased number of disastrous monsoon floods in coming decades if the climate continues to warm as expected. Since the population continues to increase at a rapid rate in the region, death tolls from monsoon flooding disasters are likely to climb dramatically in coming decades.

References
Goswami, et al., 2006, " Increasing Trend of Extreme Rain Events Over India in a Warming Environment", Science, 1 December 2006:Vol. 314. no. 5804, pp. 1442 - 1445 DOI: 10.1126/science.1132027

Dave's Landslide blog has some great discussions of the flooding and destruction wrought by the terrible monsoon rains this year in Pakistan, India, Afghanistan, and China.

Donations urgently needed
The massive humanitarian crisis in Pakistan requires a huge response by the international community. Wunderblogger Dr. Ricky Rood, author of our Climate Change Blog, has a friend working in Pakistan who underscored the desperate situation there:

This is the worst natural disaster in the history of Pakistan in terms of number of people and area affected. Although not as many people have been killed as in the 2005 earthquake, we have already nearly 900,000 displaced persons thus far just in Khyber Pakhtunkhwa. Crops are destroyed; shops, hotels, and other business have simply been swept away in Swat, which had just this year been cleared of Taliban and was on the way to recovery; and districts closer to Peshawar and parts of Peshawar district are still, or perhaps again after yesterday/today, under water. After the immediate emergency response, it will be years of rebuilding to replace what has been lost and to start to develop again. I know you have the power to control the weather, so if you cold give us a week or two without more rain at least we could keep the helicopters flying and give people a chance to go to their homes, recover what might still be there, set up tents if we can get enough to them, and start to clean up."

She gave the following recommendations for charities that do work in the flood-ravaged zone, and are effective at getting aid to those who need it the most:

Doctors Without Borders

The International Red Cross

MERLIN medical relief charity

The mobile giving service mGive allows one to text the word "SWAT" to 50555. The text will result in a $10 donation to the UN Refugee Agency (UNHCR) Pakistan Flood Relief Effort.

She mentioned that it is better to send money to the organizations doing the relief work than to try to organize shipments of goods.


Figure 2. Morning radar image of 94L from the Key West radar.

94L
A 1010 mb low pressure system (94L) near the Florida Keys is generating disorganized heavy thunderstorms over Florida and the adjacent waters, and could become a tropical or subtropical depression as early as Wednesday. Current Key West radar shows the rotation of the storm, but the thunderstorm activity has not yet organized into low-level spiral bands. A few areas in the Keys and extreme South Florida have seen 1 - 2 inches of rain thus far from 94L. Wind shear is currently a moderate 10 - 20 knots over 94L, and water temperatures are very warm, 30 - 31°C. Water vapor satellite imagery shows that 94L is forming beneath an upper-level low with plenty of dry air, and there is a substantial flow of dry, continental air wrapping into 94L. This dry air is retarding the development of 94L, and may force the storm to organize into a subtropical storm instead of a tropical storm. A subtropical storm typically has a large, cloud free center of circulation, with very heavy thunderstorm activity in a band removed at least 100 miles from the center. The difference between a subtropical storm and a tropical storm is not that important as far as the winds they can generate, but tropical storms generate more rain. There is no such thing as a subtropical hurricane. If a subtropical storm intensifies enough to have hurricane force winds, than it must have become fully tropical. It usually takes at least two days for a subtropical storm to make the transition to a tropical storm.

Forecast for 94L
The latest SHIPS model forecast predicts that wind shear will stay in the moderate range, 10 - 20 knots, over the Gulf of Mexico this week. The storm's main problem will be dry air, and I don't expect 94L to undergo rapid development. Most of the models bring 94L ashore over Louisiana by Thursday, though the GFDL model predicts 94L could stall off the coast and not make landfall until Friday. If 94L does make landfall Thursday, it is unlikely to be a hurricane, due to all the dry air aloft in the Gulf. However, the GFDL model is predicting that the 1-day delay in landfall to Friday will allow 94L enough time to grow fully tropical and intensify into a Category 1 hurricane. I think this solution is unlikely. Storms that get their start underneath a cold, dry, upper-level low very rarely attain hurricane strength in three days. A 40 - 50 mph tropical or subtropical storm at landfall Thursday or Friday is a much more reasonable forecast.

93L
A tropical wave (Invest 93) in the middle Atlantic Ocean is close to tropical depression status. The disturbance has a well-defined surface circulation, but only a limited amount of heavy thunderstorm activity, thanks to dry air and wind shear of 10 - 20 knots affecting it due to a large upper-level low pressure system to the west. Wind shear is expected to stay in the moderate range, 10 - 20 knots, over the next four days, which is low enough that 93L could become a tropical depression at any time during that period. NHC is giving 93L a 60% chance of developing into a tropical depression by Thursday 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 and 94L.

Moscow hits 99°F again today
Temperatures at Moscow's Domodedovo airport hit 37°C (99°F) today, the 28th day in row that temperatures have exceeded 30°C (86°F) in Moscow. The average high temperature for August 10 is 21°C (69°F). Moscow's high temperature have averaged 15°C (27°F) above average for the first ten days of August--a truly extraordinary anomaly. Smog and smoke from wildfires continued to blanket the city today, with the Russian Meteorological Agency reporting that pollution due to carbon monoxide, nitrogen dioxide, ozone, and hydrocarbons exceeding the safe limit by factors of 1.2 - 2.2. Air pollution levels peaked at 6.5 times the safe level on Saturday. As I reported in yesterday's post, the heat wave has likely killed at least 15,000 people in Russia so far. There is some slight relief in sight--the latest forecast for Moscow calls for high temperatures of 31 - 33°C (88 - 91°F) Wednesday though Sunday--still 20°F above normal, but better than the 27°F above normal so far this month.

"Hurricane Haven" airing again this afternoon
Tune into another airing of my live Internet radio show, "Hurricane Haven", at 4pm EDT today. Listeners will be able to call in and ask questions. The call in number is 415-983-2634, or you can post a question in the comments area on my blog during the show. You can also email the questions to me today before the show: jmasters@wunderground.com. Be sure to include "Hurricane Haven question" in the subject line. Some topics I'll cover today on the show:

1) Invest 94 and 93
2) A look ahead at the coming two weeks
3) Status of La Niña

Today's show will be about 30 minutes, and you can tune in at http://www.wunderground.com/wxradio/wubroadcast.h tml. The show will be recorded and stored as a podcast.

Jeff Masters

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Quoting msgambler:
K-Mart has em'? I'm on my way. Can I pick up one for anybody else while I'm out?
Easier to buy one off eBay@. Don't even have to get out of your chair.
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I don't have a problem with Jeff Master world weather posting but I just wish that it would not be at the expense of what is going on here in the tropics. Two invests with a high potential for development and the discussion is limited and inaccurate. I missed the days of Dr. Masters detailed descriptions of what was going on in the tropics.
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Here's a great recon decoder for anyone interested: Link
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Quoting Joanie38:


Hello Louisianaboy :)


Hey there Ma'am! How are you
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Quoting Joanie38:
Is recon going out today?? Anyone have the schedule??
they r on the way
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Quoting DownCaster:
CUARTA VEZ: Strom, is PG25L headed towards the conus?

Yeah Bud.
Florida, it looks like.
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Quoting pottery:

Good to see you, Baje!!
We are wet here in Trini, and more coming too.
How is your rainfall these days?


Hi Pottery, sorry about your flooding in T&T, tough.

Last week here was a rainout. Tow nights ago was hard rain for a few hours straight, amazing that there was no flooding, tide must have been out to allow the water away.

Lightning here is pretty active, even just now, bright clear blue sky 80%, but just north some dark clouds, and thunder and lightning'.

Lightning two nights ago blew some transformers on the poles, caused a few power outs.

I am off back to work now, I will keep in touch over the season, cheers,

Baje
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Is recon going out today?? Anyone have the schedule??
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Quoting HurricaneGeek:
Doesn't it appear that even if, I hate to use the term but, "pre 95L" were to go to the N of the Leeward it'd run into 30 knot sheer? Or is that an anticyclone I see with the yellow lines in the shape of circle?

Per post 67.

Thanks.


Any response would be appreciated, thanks! =)
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Quoting louisianaboy444:
I'm not buying this Subtropical stuff at all
That's because it isn't. 94L is warm core and will stay warm core because of the 31C+ SSTs.

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Quoting TropicalAnalystwx13:


Its certainly possible. 94L is warm-cored, not cold-cored. It wont take like a week to intensify much.


Anything is possible, But is it LIKELY?
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Quoting MiamiHurricanes09:
Looking like a tropical cyclone.



Props to you kiddo! Recon should find a Tropical Depression today, advisories should be issued by 5 p.m.
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Quoting twhcracker:


and if you drank a bottle of 30 weight motor oil, it would just absorb into your intestines and not hurt anything at all, or your internal parasites, your little amoebas and all, would eat it up and they would die but so what! you didnt need them anyway! then next year when you start passing two headed amoebas and roundworms with big goggle eyes like cantore's, you could just relax and know rush limbaugh was really on top of things when he said the ocean would take care of itself like it did in alaska.


ROFLMAO!!!!
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Quoting msgambler:
K-Mart has em'? I'm on my way. Can I pick up one for anybody else while I'm out?
its the blue light special today. send another one to btwntx08 so he can proudly display it on his wall.
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Quoting extreme236:
I'm gonna go out on a limb (although it isn't that much of a limb) that 94L is a tropical depresion.


I agree
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Quoting louisianaboy444:
I'm not buying this Subtropical stuff at all


Hello Louisianaboy :)
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Storm, here's a link with a more wide ranging paper; if covers the effect of the monsoon signal in the Indian ocean with waether patterns over the central Africanm continent as well as ENSO effects on the monsoon itself:

Interannual variability and ENSO-related anomalies

I have to renew for the other paper; it's on a pay site and I don;t appear to have saved it on this computer...

Gee, Floodman reads peer reviewed meteorological treatises...who knew?
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Quoting DownCaster:
CUARTA VEZ: Strom, is PG25L headed towards the conus?


We dont know JFV, we dont know!!!!
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I'm not buying this Subtropical stuff at all
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Quoting XLR8:
Drak,
Do you think 94 will make land fall on Thursday or Friday? (Hubby is gonna be pissed if he cant get off that rig Thursday morning..LOL)

They just stopped relief drilling right now, so he should be on his way by Wednesday if not before that.
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Quoting troy1993:
Hey MiamiHurricanes..Drakeon what do you guys think about the tropical wave east of the Lesser Antelles? Do you think it has a good shot of developing into a tropical cyclone and if it does where would the steering currents take it?


If you don't mind, I think it has a great chance of developing into a tropical cyclone.
Hmmm... I don't like how 94L is setting up... I do see the cloud-tops blowing off to the north-east on the convection near the center, but on that hi-res visible link Drak posted, it looks like a positively huge circulation!

I'm guessing that's not at the surface though right? See the cirrus clouds forming concentric rings all the way through Georgia around our center? Can someone more educated than me tell me what's going on? It looks beautiful and symmetric. Typically, that represents a strengthening storm right?

Though I confess that I know little about that phenomenon where the surface circulation goes under an upper level low.
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IKE, I didnt want to make it seem like i was bashing you i was just curious to know if you had any reasoning behind your forecast that's all
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262. JRRP

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Hey, back from school! I see our Invests are both at 60%!
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94L is impressive.

Not bad for a cold-core wannabee sub-tropical low off a trough!
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Quoting xCat6Hurricane:
gotta love the media.. CCN Meteorologist DR. Bonehead " Ahead.. We'll take a look at the tropics with a possible Hurricane in the GOMEX in next few days "

-break-

Commericial break


Its certainly possible. 94L is warm-cored, not cold-cored. It wont take like a week to intensify much.
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Just out, Relief drilling for the oil spill is being stopped at this time due to the storm.

My opinion GFDL forecast seem to be the winner this time. I don't see this storm intensifying rapidly, but It will intensify steadily so I would not be surprised if we have a Cat 1 sometime by Friday. The question is, where would it make landfall. My guess is LA coast maybe between Houma LA and the MS river delta.
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Quoting divdog:
Must be another young wipper snapper who got his meteorology degree from K-Mart
K-Mart has em'? I'm on my way. Can I pick up one for anybody else while I'm out?
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Quoting bajelayman2:


Wel said. People seem to forget that the Earth is one body, hence everything is related.

Dont you think that the heat extremes this summer in Russia and Pakistan point to a horrid winter in the North this year?

The Earth's body is living, it cleans itself, just like you and I, even iof we do not have control over some of our bodies cellular functions.

Good to see you, Baje!!
We are wet here in Trini, and more coming too.
How is your rainfall these days?
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Quoting XLR8:
Drak,
Do you think 94 will make land fall on Thursday or Friday? (Hubby is gonna be pissed if he cant get off that rig Thursday morning..LOL)


Friday
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I expect to see the LLC completely covered by convection in six hours as the ULL continues to the west....
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I'm gonna go out on a limb (although it isn't that much of a limb) that 94L is a tropical depresion.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Hello Wunderbloggers..:) HI STORMW! :) I hope everyone is well. Being in SW LA, we are not really all that concerned with 94L...sheesh..I wonder why??? I have been keeping up with it ever since it started!! LOL!
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Quoting IKE:


That right there is the reason I have him on ignore.



Must be another young wipper snapper who got his meteorology degree from K-Mart
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Quoting wayfaringstranger:


Sorry you feel that way bro. Just think - after you ignore enough people then it stops becoming a blog and your all alone or with very very few people.

Dont get me wrong - I know what your refering to but try not to let everything get to you.

If you order chicken at the KFC, they do expect you to eat the chicken and spit out the bones...right?


I have plenty of people on here...I have a Hall of Shame that are permenent ignores, then I have the seasonal ignores; seasonal ignores get removed from the igmore list form time to time...some make it to the permanent list, but not many. I will say that I'm over 100 right now, but that's including 55 permanents.

To be honest I once felt the same as you, but I find that this method works best...I feel the urge to engage in fighting far less when the idiots are weeded out of the mix. Take our three-lettered albatross; whenever I note that he has generated a new handle I ignore him...bingo!
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Quoting IKE:


No....just my amateur opinion based on what I've seen and read.

Can you back up what you think with any met reasoning?


Actually i can go to my blog i make entries all the time although i am not yet a degreed Meteorologist by any means
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gotta love the media.. CCN Meteorologist DR. Bonehead " Ahead.. We'll take a look at the tropics with a possible Hurricane in the GOMEX in next few days "

-break-

Commericial break
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Quoting Stormchaser2007:


Hot
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Quoting IKE:


I do too...a 40-50 mph TS is what I think it will be at it's strongest.

That's not that severe a system and I certainly would put the events of Pakistan, China and India over and above 94L if I was writing this blog.
I agree with you. I saw footage of what is happening in Pakistan and China. It looks horrible to say the least. Some people post more info on what they think should be posted here rather than discuss the weather events posted by the Doctor himself...Go figure...
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Quoting StormW:


Sure...if you notice in Draks last post about the ULL...it's moving westward while 94L is almost stationary. Once the ULL gets west of 94L, it will help ventilate 94L, which will begin to take care of the dry air.

Also, given the lack of an upper level anticyclone over the area, should 94L move in tandem, at the same speed as the upper level flow, this will basically nullify any shearing effect. It's not optimal for significant strengthening, but this type of process will allow for continued development, unlike Bonnie.The upper level winds during Bonnie were moving much faster in the same direction as she was, and that has a tendency to extract heat from the storm.

This situation is basically the opposite.
Thank you, for helping me understand it now.
Member Since: June 13, 2009 Posts: 0 Comments: 6752
Quoting MiamiHurricanes09:
Looking like a tropical cyclone.



that is an incredible image. that ULL is acting like an energy drink!
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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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