Overnight Thursday into Friday, Iowa once again got hit with very significant rainfall, this time across the southern third of the state. The very heavy rainfall was preceded by severe straight-line winds as well, with some of the most significant damage in Mahaska and Wapallo counties where wind speeds topped 70 mph. The greatest rainfall total received so far was at the Lake Rathbun Cooperative Weather Observer site, where a 24-hour (7 a.m. to 7 a.m.) amount of 12.34 inches of rain fell. Elsewhere across southern Iowa, from Creston and Lamoni, east through Ottumwa, Fairfield, and Keosauqua, amounts of four to six inches of rain were common. Smaller areas of 6 to 10 inches could be found from Corydon, through Centerville to Bloomfield. It is in this region where the Lake Rathbun report of a foot of rain occurred.
The image below is from our Advanced Hydrologic Prediction Service (AHPS) Precipitation Analysis website. It depicts radar estimates of rainfall and actual rain gauge measurements for the period from 7 a.m. Thu. Aug. 23, 2007 to 7 a.m. Fri. Aug. 24, 2007. You can go right to the image below by clicking here
The image below depicts the seven day combined radar and rain gauge precipitation estimation (ending 7 a.m. Fri. Aug. 24, 2007) from the same website. As you can see, much of the state has received more than five inches of rainfall in the last week.
To put these rains in perspective, an examination of rainfall departure from normal is in order. At the above website, you can also produce departure graphics. The image below depicts rainfall departure from normal in percentage for the same week ending Fri. Aug. 24, 2007.
As the image above shows, much of northern Iowa and southern Iowa are easily 400 to 600 percent above normal now for the week ending Aug. 24, 2007. This is indeed a very impressive period of rainfall, one which will be remembered for many years.
All the rain has led to significant river rises and flooding. First across northern Iowa and now in southern Iowa. The image below shows the latest river stage status across central Iowa from our local AHPS website
, where the colors of the circles are explained.
If you’re in the flooded areas of the state, please follow local officials instructions and refrain from driving as much as possible or through closed roads. Many roads are washed out or covered with water. Never drive through water of unknown depth nor any flowing water. Turn Around - Don’t Drown! (click here for more flood safety information).
Finally, the forecast looks much quieter after tonight and even more importantly much drier for the weekend. This should give rivers and flood waters to recede.
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