في أخر موضوع للخبير العالمي جيم أندروز يشرح فيه الحالة القادمة ويصفها بأمطار أستوائية قد تصل في بعض الماطق من 150 إلى 200 ملم بمشيئة الله تعالى:
--South West Asia:
With local exceptions, it cannot be said that Arabia has a "rainy season." True, some months are more favored than other (tends to be winter-early spring in the north and summer in the south), but rain is rarely more than a passing visitor on the peninsula.
Southern Arabia is coming off a major, flooding outburst of rain tied directly to a tropical weather system--03A--which landed earlier this month over eastern Yemen. Scattered downpours were strung out, south to north, all the way to Iraq.
Now, the region is looking at the strong potential for another substantial outbreak of rain. This time, there is no hint that a tropical cyclone will play any part. Yet tropical moisture would certainly do so.
At this writing, low pressure anchors an upper trough in the area of northern Iraq, southeastern Turkey and western Iran. This week, this trough has been the trigger for scattered showers and thunderstorms between the eastern Mediterranean Sea and western Iran. The trough that is forecast to instigate the rainy outbursts in question is pretty much the same one.
Drawing upon graphics from the
COLA website, here is a representative plot (200 mb streamlines to delineate the upper trough and jet stream path):
So we have the forecast scenario of a jet stream swooping out of Eastern Europe by way of Turkey and Egypt to enter the "belly" of the upper trough. From here, winds aloft are forecast to accelerate northeast to the Mideast Gulf and Iran, right over the area in question. Again, this is but a snapshot of a forecast scenario that is projected to stretch between Sunday and Wednesday.
Now, 850-mb streamlines telltale the lower atmospheric wind flow helping to steer moisture to its goal. Valid time of this plot matches the above (Tuesday, Nov. 4, 1200 UTC):
See the converging of streamlines over Arabia to western Iran in an area also marked by high relative humidity (where clouds and rain are most likely to be found at this time). Note, too, that the area of converging winds and high humidity lies east of the upper trough axis and near (slightly north of) the jet stream axis. In its essence, this is a lesson in basic meteorology.
Here, now, is how the latest (1200 UTC Thursday) GFS numerical forecast reckons rainfall for the upcoming rain outbreaks (first and third panels):
It would seem, based upon this plot, that the rains in question will spring from tropical moisture by way of the Ethiopian Highland and southern Red Sea. From here, the primary rain corridor is forecast to reach NE across the K. S. A. from near Makkah and Taif to SE Iraq, Kuwait, the NW Gulf and on into Iran. Highest forecast rainfall in "hot spots" is 150 to 200 mm (6-8 inches), which would represent at least one entire year's normal rainfall (in Arabia, anyways). Depending upon the timing/intensity of the rain, such amounts could also trigger serious flash flooding.
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Posted at Thursday, October 30, 2008 11:47 AM
10-30-2008, 04:27 PM
رد: مهم وجدير بالمتابعة: منخفض أطلسي متوقع بإذن الله تأثيره على المغرب العربي والجزيرة العربية
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