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It Is Over and the Climate Books Have Been Rewritten

August 20, 2010, 4:57:13 AM EDT

For those not already aware, this was also the year of Moscow's highest-ever temperature--and only reading above 100 F--in some 130 years of record keeping, with the high of 38.2 C/100.8 F reached on July 29.

COLD FRONT TURNS THE TRICK

A cold front swinging eastward from central Europe and the Baltic Sea first trimmed the heat in Belarus and western Ukraine on Tuesday and Wednesday.

As of Thursday, the leading edge of its cooling reached the middle and lower Volga River, thereby leaving the heat- and drought-racked Russian heartland and eastern Ukraine in its cooler wake.

Cooling will deepen into Friday and Saturday then fade early next week as a warming southwesterly flow takes hold over eastern Europe.

However, there will be no return to abnormal heat of the kind felt this summer. A "normal" warmup, yes, but not a heat wave.

INDUS RIVER FLOOD CREST STILL HEADING FOR THE SEA


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Visible satellite image showing the rain-swollen Indus River squeezing past the Guddu low dam at Kashmoor, Pakistan. This is at the Punjab-Sindh border. The structure is not at all narrow--it's nearly 2 km wide! The flood waters here spread about 15 km wide, and they are even wider along many reaches of the Indus elsewhere. Beneath these murky waters, partly visible here, lie some of the millions of acres of cultivated land and thousands of farms that have been inundated by the Great Pakistan Flood of 2010. (Image Credit: NASA/Earth Observatory)


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Visible satellite image showing the same site, but with a more typical summer flow. The braided channels and huge sandbar islands bespeak a sediment-choked stream draining actively building mountains (Karakoram, Himalaya, Hindu Kush) as well as naked desert slopes of rock and earth. (August 2009) (Image Credit: NASA/Earth Observatory)

The Pakistan Meteorology Department (PMD) have the Indus River crest located somewhere in the area of Sukkur in northern Sindh as of Aug. 19.

There have been two crests between one and two weeks apart. These may have merged. Or the first one damped out. Then, too, a first crest may have already passed through the mouths of the Indus.

One way or another, the worst of river flooding has yet to reach a significant reach of Indus flood plain in middle and southern Sindh, including the area of Hyderabad and Kotri.

Flow at Kotri, last gauge along the Indus, has held well below the river's highest flow upstream. This peak flow rate upstream seems to have been about 1,200 thousand cubic feet per second (cusecs) during the first week of August.

A flow rate of 1,100 thousand cusecs seems to have happened this week with the second crest.

These flow rates were estimated for the flow at Guddu and Sukkur low dams, or for southernmost Punjab into northern Sindh.

The highest actual flow indicated by PMD at Kotri was 500 thousand cusecs or less, although forecast rates have been as high as 800 cusecs (first crest) and 900 thousand cusecs for the latter crest.

I do not know where the "lost" flow went. To canals? Under reckoning of loss to the flood plain?

HEADWATERS ARE RECEDING THANKS TO DRIER WEATHER

There being a lack of any widespread soaking rain during the last few days, the way has been paved for a marked lowering of flow rates on the upper Indus and its Punjab tributaries.

The lower flow rates will translate downstream through the core of the flood-stricken area, thereby allowing high water to recede.

Unfortunately, the flat nature of the flood plain, which has flooded in a swath 25 km and more across, will mean a relatively slow end to the inundation.

TIME RUNNING OUT FOR SW MONSOON 2010

Withdrawal of the SW Monsoon from the plains of Pakistan is normally done by the first of September. It takes a week or two longer to shut off along the foothills and high mountains.

This would imply little time left for any widespread excessive rainfall before onset of seasonal dry weather.

However, latest numerical forecasts (GFS and others) are indicating localized torrential downpours, mostly along mountains and foothills, even southward along the Sulaiman Range.

Were there to be any more flooding rain, I believe that the result would be flash flooding and not another lumbering inundation of the Indus flood plain.

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