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 cirrocumulus:
I'm going 60% right now on 91L. No money at stake on the bet. I am hedging on warm water temps overriding the MJO.


That's probalby a good bet right now assuming that a solid low can develop over the next few days........
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I'm going 60% of a hurricane on 91L.
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Quoting nrtiwlnvragn:
Interested to see where in that 500 mile orange circle they initiate an invest.


wondering the same thing as the initialaztion point could offer a variety of solutions.
Member Since: July 7, 2005 Posts: 0 Comments: 5120
Quoting JeffMasters:


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.

What about the China flooding? According to the Dartmouth Flood Observatory, the recent floods in China have killed over 1,100 people. I know you stated that as many as 3,000 may have been killed, but if that number doesn't verify, the recent Chinese floods may have been deadlier.
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ftp://ftp.ssec.wisc.edu/pub/mimic_tpw/animations/natl/2007/20071017T000000anim72.gif

http://cimss.ssec.wisc.edu/tropic/real-time/tpw2/natl/anim/latest72hrs.gif

Does anybody see a difference in the flow of the air masses between 2007 and 2010?

The first is from September 17, 2007

The second is from today.

Could that be why the storms aren't forming as predicted?

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I'm going 60% right now on 91L. No money at stake on the bet. I am hedging on warm water temps overriding the MJO.
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Quoting Bordonaro:

Yeah, we'll see that weather come late November this year!


15 Degrees + Snow. My favorite! :)
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Quoting Levi32:


Ouch lol. 52 degrees and raining here.

Yeah, we'll see that weather come late November this year!
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Interested to see where in that 500 mile orange circle they initiate an invest.
Member Since: September 23, 2005 Posts: 13 Comments: 10466
Quoting Levi32:


Ouch lol. 52 degrees and raining here.


I would love to live in Alaska during the Winter. ;)
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Quoting KEEPEROFTHEGATE:
AOI/XX/XL
MARK
7.7N/35.1W


Like I said, it's very disorganized, but it has a lot of convection to work with.
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Quoting Bordonaro:

Thanks Levi32. I sure would love to borrow some of your rain and cool temps.

At the DFW, TX AP, it's 96F, dew point 68, heat index a toasty 101F!!


Ouch lol. 52 degrees and raining here.
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Area east of the Antilles associated with a tropical looks interesting. Not very impressive, but it is under favorable conditions.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
True Levi: I thought you meant all of the Pacific. The Central is going to have a dud of a year.
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Quoting Levi32:


The disturbed weather near the Bahamas is associated with the tail-end of an old front that is draped down in the area, and although these frontal boundaries should always be watched over this exceptionally warm water, it doesn't appear to me to be a threat for tropical development.

The cluster of showers in the central Gulf of Mexico is associated with a weak surface trough that is not a threat for tropical development.

Thanks Levi32. I sure would love to borrow some of your rain and cool temps.

At the DFW, TX AP, it's 96F, dew point 68F, heat index a toasty 101F, at 12:53PM CDT. Dew points should drop to 56F by 5PM, with a toasty 101F high expected.
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I still am confused as to why our disturbance is not 91L.

Judging by this visible loop, it continues to become better organized.
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Quoting Levi32:
The central Pacific is trying hard right now with a decent-looking invest, but you won't see many of these this year out there with the La Nina as intense as it is. SSTs are well below normal. A normal year in the central Pacific has 4-5 named storms, but I wouldn't be surprised to even end up with zero this year. A random system like this one though, could have a shot at racking up one or two for them.



Issued: Jul 31, 2010 2:00 am HST

For the central north Pacific, between 140°W and 180.

1. A surface trough located less than 1200 miles east southeast of Hilo, Hawaii has disorganized showers and isolated thunderstorms associated with it. Although upper level winds are currently not conducive for any significant development of this system, these winds may relax slightly later this weekend as this trough continues moving westward at 10 to 15 mph. There is low chance, 20 percent, of this system becoming a tropical cyclone during the next 48 hours.

Elsewhere, no tropical cyclones are expected through late Sunday night.
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AOI/XX/XL
MARK
7.7N/35.1W
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Quoting cirrocumulus:
Levi: I agree. Except that the Pacific has so many that they will have a few. lol.


Yeah well the eastern Pacific averages 15 a year, 2nd most in the northern hemisphere, but the central Pacific only has 4-5 a year on average, which is what I was talking about.
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Quoting itrackstorms:
I know the good Doctor is on vacation... but that is one lousy updated blog.


Its July 31st & Dr Masters is probably working on the outlook for August. At the beginning of each month he gives a detailed analysis for that month. Expect to see this early next week. I expect him to mention the A/B high in this blog.
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Quoting cirrocumulus:
First hurricane ever, developing on land captured in west Africa:

Would you please explain...or were you being sarcastic?
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Levi: I agree. Except that the Pacific has so many that they will have a few. lol.
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Quoting Bordonaro:
What is up with the cluster of convection near the Bahamas and the small cluster of convection in the Central GOM??


The disturbed weather near the Bahamas is associated with the tail-end of an old front that is draped down in the area, and although these frontal boundaries should always be watched over this exceptionally warm water, it doesn't appear to me to be a threat for tropical development.

The cluster of showers in the central Gulf of Mexico is associated with a weak surface trough that is not a threat for tropical development.
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Quoting CapeCoralStorm:
I find it odd that there can be a orange circle at 30% on something thats not classified as an invest. Strange to me.


One of the two areas in the circle will be designated 91L soon enough.
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Quoting CapeCoralStorm:
I find it odd that there can be a orange circle at 30% on something thats not classified as an invest. Strange to me.

Meteorology is not an exact science, like math or physics. There is ample convection, lower pressures and a dissipating 90L being energized by a TW (tropical wave). Add 85F SST and low shear, voila', the makings of INVEST 91L.
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Quoting RJT185:
I wonder what their basis was for breaking out the orange crayon.
Maybe because the gfs picks it up and heads it west as a tc. Just a guess though.
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CMC rationale:

TROPICAL WAVE EXTENDS ALONG 19N51W TO 13N50W TO 08N46W MOVING W
AT 10-15 KT. THE WAVE AXIS COINCIDES WITH A MID-LEVEL TROUGH
AXIS THAT CONTINUES TO GENERATE SCATTERED MODERATE AND ISOLATED
STRONG CONVECTION FROM 12N TO 16N BETWEEN 50W AND 53W. EARLIER
ASCAT AND WINDSAT SCATTEROMETER PASSES CAPTURED NON-RAINED
FLAGGED NE WINDS IN THE RANGE OF 20 TO 25 KT FROM 15N TO 17N
BETWEEN 48W AND 52W...MAINLY N OF THE CONVECTIVE AREA.
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Quoting RJT185:


this is the first time i've managed to come update myself on the tropics in a couple days, i'll definitely have to go check out your blog. thanks!


I dont have a blog (not good enough yet); I made the comment on Dr. M's blog this morning....... :)
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Quoting CapeCoralStorm:
I find it odd that there can be a orange circle at 30% on something thats not classified as an invest. Strange to me.


Agreed. That's why I was curious for their decision to go "Orange" on us with that particular update.
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The central Pacific is trying hard right now with a decent-looking invest, but you won't see many of these this year out there with the La Nina as intense as it is. SSTs are well below normal. A normal year in the central Pacific has 4-5 named storms, but I wouldn't be surprised to even end up with zero this year. A random system like this one though, could have a shot at racking up one or two for them.

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Quoting 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.
the result of increasing amounts of water vapour in the atomsphere over time this will become the norm
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Quoting TOMSEFLA:
all long range models show low pressure over ne us so if there correct anything over bahamas will curve nw to n to ne. will see


Fishcaster
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Quoting weathermanwannabe:


Too early to tell where this one will go but as I mentioned on the morning blog, emerging La Nina conditions seem to favor slightly higher trajectories so we might see a few storms affect PR this year on the way towards Florida and the Gulf.


this is the first time i've managed to come update myself on the tropics in a couple days, i'll definitely have to go check out your blog. thanks!
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What is up with the cluster of convection near the Bahamas and the small cluster of convection in the Central GOM??
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I find it odd that there can be a orange circle at 30% on something thats not classified as an invest. Strange to me.
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First hurricane ever, developing on land captured in west Africa:

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Quoting RJT185:


It does serve as a very good SAL-shield. I wish I was at my home computer to pull maps and see myself. :) Storms in that locality always makes me wonder if PR will see its next big hit since Georges. :-/


Too early to tell where this one will go but as I mentioned on the morning blog, emerging La Nina conditions seem to favor slightly higher trajectories so we might see a few storms affect PR this year on the way towards Florida and the Gulf.
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My gut tells me that a hurricane is going to hit New England this year. JMO
Member Since: July 7, 2010 Posts: 0 Comments: 5521
12z CMC still confused and tries to develop a 2nd system near 40W that eventually tries to merge with ex-90L. This is likely another feedback issue with the CMC and is compromising its forecast.
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Quoting weathermanwannabe:


My guess would be that the abundant moisture field factored into the equation......Along with the factors noted by Dr. M.


It does serve as a very good SAL-shield. I wish I was at my home computer to pull maps and see myself. :) Storms in that locality always makes me wonder if PR will see its next big hit since Georges. :-/
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Quoting deautschlandfutbol:
So it looks as if the a/b ridge is setting up for a florida hit over and over this year. Hey hollywood r u in fla?


yes I am in fla
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Quoting Snowlover123:


Everyone, from the Gulf to the East coast, should monitor this extremely closely. Do you agree? :)
Not yet...if it develops into a tropical depression then we talk, but at this point there is still a great amount of uncertainty past 65W.

Be back in a bit.
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Quoting RJT185:
I wonder what their basis was for breaking out the orange crayon.


My guess would be that the abundant moisture field factored into the equation......Along with the factors noted by Dr. M.
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Quoting MiamiHurricanes09:
The better question is...where will it go after that?


Everyone, from the Gulf to the East coast, should monitor this extremely closely. Do you agree? :)
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Quoting MiamiHurricanes09:
The better question is...where will it go after that?
all long range models show low pressure over ne us so if there correct anything over bahamas will curve nw to n to ne. will see
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I wonder what their basis was for breaking out the orange crayon.
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So it looks as if the a/b ridge is setting up for a florida hit over and over this year. Hey hollywood r u in fla?
Member Since: June 20, 2010 Posts: 0 Comments: 73
Quoting nrtiwlnvragn:
TAFB Experimental Gridded Marine Forecast

Wind 8AM EDT Aug 6





Pressure




Looks like an eye. :o
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Quoting MiamiHurricanes09:
The better question is...where will it go after that?


Your going to have to wait a few years for 7 day forecasts from NHC/TAFB.
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Poor Pakistan.
Member Since: July 7, 2010 Posts: 0 Comments: 5521

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.