The latest U.S. drought monitor for Minnesota spelled out more bad news. The Twin Cities is back in severe drought and extreme drought more than quadrupled to cover a full ten percent of the state now.
The increased severity in the drought this week is largely due to the rare late August heat wave we had last week and only localized, isolated areas of any rainfall in the past seven days.
When we compare last week’s drought monitor (which is data valid through August 22) and this week’s (valid through August 29), we can see the major changes are the extreme drought swaths in north central Minnesota and southeast Minnesota. Note also much of east central Minnesota which had moves into just ‘moderate drought’ are now back into severe drought.
Rainfall deficits through August 30 are pretty dismal. These are the amounts of rainfall we’re behind since June 1 (start of meteorological summer):
What’s almost more troubling is that the progress we had made up in early August has basically been erased with the recent couple of weeks of dry weather and consistently above normal or even hot temperatures.
The above chart shows the percent of normal precipitation for the month of August. You can see with some of the rains we saw in the second week of August got up to about 55% of normal summer precipitation but every dry day that goes by after that we grow our deficit and that percentage drops. After this weekend we’ll be back to where we started the month.
The forecast for the next several days shows little or no rainfall. This forecast is through early Tuesday (September 5).
It will be nearly impossible to make up our nearly 7 inch rainfall deficit this fall. That’s because fall averages less rainfall than summer. September averages 30% less rainfall than August and October is 15% less than even September rainfall. We’d have to receive more than double our normal fall rainfall over the entire three month period to make up that kind of deficit.
Of course last year over the course of the fall, winter and early spring we did make up the deficit from the summer drought but our deficit wasn’t as large and we weren’t in an El Nino winter pattern. Typically, El Nino winters yield less precipitation but we shall see.
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