Pakistan monsoon floods kill at least 800

By: Dr. Jeff Masters , 5:56 PM GMT on July 31, 2010

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The deadliest weather disaster of 2010 is unfolding in Pakistan, where heavy monsoon rains have triggered flooding that has left at least 817 people dead. A death toll may reach 3000, according to the local head of Pakistan's largest rescue service, and more monsoon rains are on the way. Monsoon floods have also hit southeastern Afghanistan hard, where at least 64 have been killed. The heavy rains were caused by a monsoon depression (also called a monsoon low) that formed over the Bay of Bengal 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, resulting in that nation's worst floods since at least 1929. 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 monsoon depression is similar to a tropical depression, but forms in the Indian Southwest Monsoon over the Bay of Bengal. Like tropical depressions, monsoon depressions are hundreds of miles in diameter, have nearly calm winds near the center, and can have sustained winds of 30 - 35 mph. Four monsoon depressions originated in the Bay of Bengal in 2009; the average is 6 - 7. A new monsoon depression developed over the Bay of Bengal yesterday, and is headed westward towards Pakistan. Heavy rains from this new monsoon depression will begin affecting Pakistan on Monday, according to the Pakistan Meteorological Department.


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.

Tropical Atlantic may get active by mid-week
The Invest 90L tropical wave off the coast of Africa has grown disorganized, and NHC is no longer generating forecast tracks for the system. A tropical wave that moved of the coast of Africa Thursday is in the eastern Atlantic near 10N 25W, a few hundred miles south of the Cape Verdes Islands. This morning's 12Z run of the NOGAPS model predicts that this wave will develop into a tropical storm by Wednesday, and reach the Lesser Antilles Islands Friday. This morning's 12Z run of the GFS and ECMWF models predict that an area of disturbed weather near 8N 37W, in the east-central Atlantic, will develop into a tropical storm that will move through the Lesser Antilles on Thursday. Wind shear is low to moderate, sea surface temperatures are at record highs, and the dust and dry air of the Saharan Air Layer (SAL) are far enough to the north of these disturbed areas to potentially allow formation of a tropical storm. However, the Madden-Julian Oscillation currently favors downward motion over the tropical Atlantic, which will act to decrease the chances of tropical storm formation. NHC is giving a 30% chance that a tropical depression will form by Monday afternoon from one of these areas of disturbed weather.

Next update
I'll have an update Monday morning at the latest.

Jeff Masters

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Quoting Levi32:


If you look very closely at the low-level cloud structure you'll see that it's a little more south of that, closer to 8.5N.
You got some good eyes Levi. If you wouldn't of mentioned it I wouldn't have noticed. 8.5N and 36.1W looks about right to me.
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Quoting muddertracker:
roflmao!

I'll say "Make my day" liked the Clint Eastwood pic you posted earlier, He's 80 now, Father Time sure works on all of us, blessed are those that stick around for Father time to work on that's my motto, afriend of mine the other day told me he didn't like the idea of getting old, I told I didn't like the alternative, he asked well what's that I said Dying young, he bursted out laughing!
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Quoting MiamiHurricanes09:
Based on shortwave loops I would put circulation of ex-90L near 9.2N and 36.1W.


EXACTLY where I would put it.
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I agree MiamiHurricane09 with those coordinates. 91 has made steady progress today and is lifting northward.
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Quoting ElConando:
I'll be on Vacation for a week so It will be interesting what I see when I find back.


it's cool to leave the blog for a while and come back to something, rather than sit and painstakingly watch every little move the wave makes. I try to stay away, but always find myself checking in
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Quoting Tazmanian:
i hop La Nina dos not get too march strong or it will start shuting thing down this like they have had for the W PAC




The La Nina will be very strong, as indicated by many models.

http://www.cpc.noaa.gov/products/people/wwang/cfs_fcst/images3/nino34SSTMon.gif

http://www.jamstec.go.jp/frcgc/research/d1/iod/2007/forecast/ssta.nino3.4.fcst.1jul2010.gif

http://www.jamstec.go.jp/frcgc/research/d1/iod/2007/forecast/ssta.nino3.4.fcst.2-yr.1jul2010.gif
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Hey look! Interest #1 is at 40%. I think that we could be talking about a tropical system in 48-72 hours time.
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1162. aquak9
Quoting jurakantaino:
Invest means and area under investigation that have probabilities to develop, right? That's why I didn't give it a number, ex 90L or new 91L? waiting for them to do It...


you're right, they tag it with an L. Next number up, it'll be 91L. Don't think they'll re-use 90L.
Member Since: August 13, 2005 Posts: 178 Comments: 26681
. Levi32 plz look at commet 1157 thanks
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
1159. Levi32
Quoting MiamiHurricanes09:
Based on shortwave loops I would put circulation of ex-90L near 9.2N and 36.1W.


If you look very closely at the low-level cloud structure you'll see that it's a little more south of that, closer to 8.5N.
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i hop La Nina dos not get too march strong or it will start shuting thing down this like they have had for the W PAC


Member Since: May 21, 2006 Posts: 5091 Comments: 115456
Quoting aquak9:


they haven't invested it yet...have they?
Invest means and area under investigation that have probabilities to develop, right? That's why I didn't give it a number, ex 90L or new 91L? waiting for them to do It...
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Quoting MiamiHurricanes09:
The large circle remains.



Can you say "CYA"? It's that time of year.
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Quoting clwstmchasr:


Jeff, there is no way to be that confident that the steering is so straight forward when you are talking 10-14 days out. A heck of a lot can change by then.


Yeah, and "well guess what I told you guys" posts are particularly annoying before the evidence is in.
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Quoting CybrTeddy:
If this gets to red and is still isn't a invest I'll start wondering if this will be the first system to skip invest phase and go from blob to TD.
roflmao!
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Based on shortwave loops I would put circulation of ex-90L near 9.2N and 36.1W.
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1150. KEEPEROFTHEGATE (Mod)

NMFC Norfolk Tropical Feed
No Active Tropical Warnings in the Atlantic, Caribbean, or Gulf of Mexico
By Maritime.CDO@navy.mil (NMFC CDO) from Naval Maritime Forecast Center Norfolk Virginia. Published on .

As of Sat 31 Jul 2010 23:45:01Z
2010 Storms
All Active Year

Atlantic
NONE
East Pacific
97E.INVEST
Central Pacific
92C.INVEST
West Pacific
95W.INVEST
Indian Ocean
NONE
Southern Hemisphere
NONE
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1149. xcool
deautschlandfutbol huh hmmm
Member Since: September 26, 2009 Posts: 2 Comments: 15684
1148. Levi32
Notice what the warm water in the Atlantic in combination with the La Nina has done. The focus of heat is drawn towards the Atlantic and so the mean upper ridge is pulled up over the Gulf of Mexico and NW Caribbean. This is a favorable pattern for development in our basin, but a lousy one for the eastern Pacific because strong easterly shear on the south side of the high is screaming across there. This is why Invest 97E is falling apart out in the eastern Pacific.

That's what happens in a La Nina year....the Atlantic gets all the heat and the eastern Pacific gets sheared. This is important to remember because some don't realize that the eastern Pacific doesn't get sheared by upper westerlies during a La Nina, but by upper easterlies because of the upper ridging getting pulled farther north into the Atlantic.



97E getting a shave:

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1147. aquak9
Quoting jurakantaino:
NHC gives the disturbance south of CV, 40%, high for our new brand Invest...


they haven't invested it yet...have they?
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Have a nice one ElConando hope its no more than a couple of broken branches when you get back.
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Quoting deautschlandfutbol:
Dude I have been saying it for 3 days now just not in here. It looks like a frenzy for florida this year. That neg nao and where that a/b high is. I have learned a lot from storm in mh09 and I leaned it all in a week. plus I have a weather book I have been studying.

hmmm ?
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Quoting Patrap:
1100 Post on nothing.

Wu-tastic.



Holy cow! West Africa exploded........LOL
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I think 91 is at 9.2 and 35.1. It's gaining latitude now.
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Filibuster your not geting it yet aret you

you post you get re ported and you commets get re move
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Quoting CybrTeddy:
If this gets to red and is still isn't a invest I'll start wondering if this will be the first system to skip invest phase and go from blob to TD.
I would like it to get tagged an invest now that it is more organized than 2 days ago to see what the models are showing.
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Doc posted about this exact scenario the other day about 90l being caught by wave coming off Africa.Combining on Sunday with one becoming more dominant. Looking at satellite I saw some spin all the way from 9n 40w to 9n 33w with 33w having much better convection.
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Dude I have been saying it for 3 days now just not in here. It looks like a frenzy for florida this year. That neg nao and where that a/b high is. I have learned a lot from storm in mh09 and I leaned it all in a week. plus I have a weather book I have been studying.
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Quoting MiamiHurricanes09:
The large circle remains.



Indicating the circulation is quite broad.
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If this gets to red and is still isn't a invest I'll start wondering if this will be the first system to skip invest phase and go from blob to TD.
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90L could be re-up or 91L will take over ?
Member Since: August 23, 2006 Posts: 0 Comments: 1592
The large circle remains.

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NHC gives the disturbance south of CV, 40%, high for our new brand Invest...
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Quoting Levi32:


They usually do, which is one reason why this will continue to be very slow in getting going, and will have a better chance once it gains some more latitude, which will also start happening during the next 48 hours.


I know, I'm edumacated. Thanks, I love agreeable folks. The ITCZ has a tendency to fool a lot of people.....with all its convection this time of year.
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I'll be on Vacation for a week so It will be interesting what I see when I find back.
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the E pac has two yellows
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
I see the broad area of circulation near 9.5 N and 35.0 W.
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1126. NRAamy
PINHOLE EYE!!!!!!!
Member Since: January 24, 2007 Posts: 317 Comments: 31946
Quoting Levi32:


I don't think it's a problem for tropical development. You're thinking of large areas of disturbed weather that are so large and complex that sometimes they never develop or are very slow in doing so. That is something you often see in other basins in the northern hemisphere, but here in the Atlantic it's not as much of a "problem" because we have tropical waves, features that are unique to our basin and provide local focus-points for air to pile up and tropical cyclones to form. And besides, I can think of several ways conditions could have been more favorable so far this year. This isn't perfect.

ditch the SAL, lift the tutt, drop the AB high center .....
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1123. Patrap


Hundreds of people have died in northwestern Pakistan after floods triggered by monsoon rains swept through the region.

More than a million people have been affected and thousands forced to flee their homes as bloated rivers washed away villages and triggered devastating landslides.

Rescue operations are underway to save the stranded, but submerged roads and destroyed infrastructure are proving to be major obstacles.

Al Jazeera's Sohail Rahman reports from Islamabad, Pakistan's capital.
Member Since: July 3, 2005 Posts: 428 Comments: 129906
am thinking 50-60% for the next two
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1121. NASA101
...and NHC says System moving West....
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the new TWO is out and its up to 40%

A LARGE AND COMPLEX AREA OF DISTURBED WEATHER CONTINUES OVER THE
TROPICAL EASTERN ATLANTIC. THE ASSOCIATED SHOWER ACTIVITY HAS
BECOME SLIGHTLY BETTER ORGANIZED THIS EVENING ABOUT 850 MILES
WEST-SOUTHWEST OF THE CAPE VERDE ISLANDS. CONDITIONS APPEAR
FAVORABLE FOR ADDITIONAL SLOW DEVELOPMENT AS THE DISTURBANCE MOVES
WESTWARD AT 5 TO 10 MPH...AND THERE IS A MEDIUM CHANCE...40
PERCENT...OF TROPICAL CYCLONE FORMATION DURING THE NEXT 48 HOURS.
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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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