Pakistan's Katrina; 94L could develop in Gulf of Mexico
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
Reader Comments
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Actually its a TROPICAL weather blog. Dr. Masters has the right to post whatever he wishes, obviously, because its his blog. But I only follow this blog for TROPICAL reasons since that is what this blog is supposed to be. I don't even bother looking at other world events he posts.
Hmmm, ok, well if we put this Invest close to 50W and 11N then what I can see from the steering pattern you posted is that it will should move WNW?
Don't really put a lot of emphasis on these steering patterns - Colin was suppose to graze the northern islands according what the steering patterns but it did not verify...
Anyway, just my take on things here... :)
I dont think that he has been 'ignoring' Tropical Weather at all.
And in reality, his posts on Climate Change (or whatever we care to call it) are completely relevant to the subject of Tropical Weather (and by extension, Climate).
There really is not very much going on in the Tropics right now.
I am sure Dr. Masters will keep his posts relevant to the Tropics when things warrant that.
It is probably because an invest are just that a invest. I am sure if this was a hurricane, he would have dedicated the whole blog to the storm.
Besides 2 million people homeless due to floods in Pakastain is a little more news worthy than a invest.
From the point of view of that animation, it almost looks like the ULL to the north is helping 94L along at this time.
A help, not a hindrance?
I agree, seems like things are slipping
I think they'll be there by 2 pm Eastern Time.
MJO hint I'm sensing here?
Good call doc. That won't be such a big issue if it verifies. I agree with your forecast.
Oh I completley agree, don't get me wrong =) But at least mention accurate facts when talking about the invests!
So do I, but I am more concerned with the mis-information of the invests.
The caps are incredibly unneccesary and rather annoying. It has nothing to do with disrespect towards people dying, and it could've certainly been mentioned in his blog...the only problem I have is that the 94L section of the blog isn't entirely accurate and much of it does not pertain to 94L.
I can see how much you know about weather, "There really is not very much going on in the Tropics right now."
The above image shows nothing, compliments of pottery.
GOOD CALL...I'm going on vacation pottery says its all clear.
Thats a shame really.
The Weather is all inter-related. It is actually Global.
What happens in Pakistan this week is caused by weather that gives us hints as to what could happen in other areas in the short/medium term.
Different opinions are good.
I like the Big Picture, and come to this blog for that.
*steps off soapbox*
Darn, well it wasn't a bad guess lol...But I did not know that the Monsoon correlates to stronger wave activity. Very interesting.
wow don't get your panties in a bunch!
I am not saying it should be ignored. I am saying I would like accurate information on the invests at least. If I lived in thsoe areas, I wouldn't be reading a weather blog based out of the US, thanks. I am not saying I do not care to hear about the devestation happening elsewhere. Take a chill pill, wow.
There is a factor in tropical cyclogenesis that we cannot quantify yet. When it looks like 2+2=5, we are missing a 1 somewhere. Some systems fight bad conditions, and some, it seems to us, fight good conditions LOL. The ones that appear to fight good conditions tend to create problems for themselves, like creating multiple spins, or achieving a steady state with only a third of the circulation covered, as 93L did even before the shear got hold of it. Cyclones try to achieve an optimal state of ventilation, circulation, and intensity for whatever the surrounding conditions are. There is some unknown factor that makes the optimal state for some disturbances in "fantastic" conditions something other than a tropical cyclone.
It's arguably as important to know why systems fail to develop, or develop very very slowly, as it is to know why they do develop.
That was a bit over the top.
We are in a world of ones and zeros here. Yes it is sad so many people are dying, but such is life. A complaint or two to Dr. Masters in search of a more focused blog does not diminish or trivialize in any way the loss of so many.
It's just ones and zeroes, dude. If assembled correctly, information results.
000
URNT15 KNHC 101608
AF300 01DDA INVEST HDOB 02 20100810
155900 3025N 08855W 0110 00009 0118 +301 +276 051007 010 /// /// 03
155930 3026N 08854W 9883 00219 0129 +280 +277 048006 007 /// /// 03
160000 3027N 08853W 9701 00382 0124 +264 //// 049006 007 /// /// 05
160030 3027N 08851W 9429 00632 0124 +246 //// 063006 007 /// /// 05
160100 3027N 08849W 9190 00871 0137 +234 //// 079007 007 /// /// 05
160130 3026N 08847W 9111 00942 0142 +227 +205 077008 009 /// /// 03
160200 3024N 08847W 9119 00934 0142 +228 +180 061009 009 /// /// 03
160230 3023N 08847W 9080 00971 0147 +222 +159 066008 009 /// /// 03
160300 3021N 08847W 8735 01304 0142 +199 +140 070013 015 /// /// 03
160330 3019N 08847W 8327 01714 0142 +168 +123 070018 018 /// /// 03
160400 3017N 08848W 8051 02000 0141 +151 +105 068020 020 /// /// 03
160430 3016N 08849W 7796 02278 0146 +134 +089 071019 019 /// /// 03
160500 3015N 08851W 7522 02577 0147 +116 +074 067017 018 /// /// 03
160530 3014N 08853W 7289 02843 0139 +107 +060 046017 018 /// /// 03
160600 3013N 08854W 7092 03074 0125 +107 +047 046016 018 /// /// 03
160630 3012N 08856W 6978 03208 0117 +105 +037 053017 018 /// /// 03
160700 3010N 08858W 6987 03197 0119 +105 +029 054017 017 /// /// 03
160730 3009N 08901W 6981 03208 0123 +103 +021 053015 016 /// /// 03
160800 3008N 08903W 6969 03218 0128 +096 +015 049015 016 /// /// 03
160830 3006N 08905W 6980 03202 0124 +096 +012 050015 015 /// /// 03
$$
;
I don't understand the dilemma.. o_O
HAHA even i got that one! as for tropics i was hoping someone would elaborate more on the dry air north of 94L and how it will affect things. Like is thats what is steering? Or is that something that will just impede strength. is that dry air a HIGH that will make the rain go around us here in panama city area? inquiring minds. and yes i read your blog Storm but forgive me if I didnt retain it i am only firing on so many cylinders today.:)
Storm, I cannot remember the author, but I read a paper a couple of years ago that indicated a heightened Monsoon event would result in more frequent and stronger (as well as persistent) African waves...
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