Posted: Jul 19, 2012 8:34 AM by Dave Baker
Updated: Jul 19, 2012 8:50 AM
The latest drought index shows more problems for crop areas of the Midwest. Triple digit temperatures and lack of rainfall are pushing farmers to the limit. The crop losses could increase prices for groceries in the coming weeks.
A weather pattern called an "Omega Block" has been parked across the middle part of the nation for the past several weeks. This is when the jet stream dips south along the west coast, then ridges northward toward the Canadian border across the mid section of the nation, then dips again across the northeast..similar to the Greek letter Omega (Ω). This pattern keeps the east and west coasts wet while blocking storm systems from the Midwest. The result, heat and drought.
This pattern was similar to droughts in the 1930s, 1950s, and the great drought of 1988-89. The difference between this drought and '88 drought is the length. Last year and this spring had normal or above normal precipitation for the Midwest, so the drought hasn't persisted as long as past droughts have. Sure, more areas are drier than normal, but the drought index in the "extreme" or "exceptional" category isn't as widespread.
Compare the drought maps from last year and today. There was a much larger percentage (over 25%) that was in "exceptional" or "extreme" drought. Today it's a little over 10%. But only 1/4 of the nation is wetter or normal. Last year more than half of the nation was in good shape for moisture.
One Year Ago (Top) vs. Today (Bottom)