Meteorologists have attributed this year's weather patterns to shifts in patterns of water temperatures in the east Pacific called La Nina, (pardon the missing tilla,) which have shifted the jet streams over the continental USA.  Relatively stable conditions with disastrous consequences will set up and remain in place for weeks at a time.  In the central USA this often involves the intersection of warm, moisture laden air from the Gulf of Mexico or from the Pacific coast of Mexico with a dipping jet stream accompanied by colder air.  Two air masses moving at different altitudes and in different directions constitute the conditions, (rotation), for thunderstorms, hail and tornadoes, the number of which is on track to set new records this year.

Solar heating sets up a diurnal storm pattern under these conditions.  We regularly see thunderstorms popping up towards the western edge of the plains, from Texas to the Dakotas, that them move eastward over the next 24-48 hours.  As the year has progressed we have seen the intersection point of the gulf air and the jet stream move north.  In February and March we had storms moving from Texas and Oklahoma to the east.  Now the points of origin seem to have shifted further north, from central Oklahoma to Nebraska.  In the absence of strong weather systems moving from the Gulf of Alaska east across the continent, the weather can become stuck in a pattern, with massive amounts of rain being dumped over the same areas day after day.

In March and April this pattern set up over Arkansas and left all of the Army Corps of Engineers' reservoirs in the Ozark watershed full.  As additional rain fell, water had to be released downstream.  This was as traumatic for the ACOE operators as it was damaging to communities and farm lands down stream.  Senior ACOE officials appeared before affected downstream communities with tears in their eyes to explain that they had no choice but to open the floodgates.

This was combined with the sad fact that poor counties in eastern Arkansas had dissolved levee boards in the '50s and 60s because of the expense and lack of perceived need.  The result was that the rich bottom lands along the Mississippi and some towns were flooded, and some may remain flooded.  This has prevented or delayed farmers from getting crops, especially rice, of which these lands are large producers, in the ground.  Soft red wheat, on the other hand, which is grown on higher ground, seems set for a banner year--if farmers can get the crop harvested.

Now this pattern has set up further north.  Compared to the Ozark water shed, there is less reservoir capacity in those areas.  A stable downpour occurred over parts of Iowa, Wisconsin, Illinois and Indiana last week.  This is being referred to as a "once in 500 year event."  My feeling is that prospectively such events might become once in 50 year events.  Global warming may increase the energy and possibly the capriciousness of these types of events.  

As the Dutch said while fighting the Spanish: "It is not necessary to have hope in order to persevere."