If you listen to MPR News on Thursday mornings you've heard Daily Circuit host Kerri Miller and I explain the term "weather whiplash." I'd like to say I invented the term, but to give credit where credit is due it was coined a few years back by Climate Central's Andrew Freedman to describe rapid extreme swings in weather patterns seemingly caused by a new trend of a slower jet stream. Weather patterns just seem to get stuck in one extreme, then another.
Minnesota has been ground zero for weather whiplash in 2013.
We started the year with 100% of Minnesota in drought, then dramatically erased a 10" to 12" moisture deficit last spring and early summer. Fast forward to July and the weather faucet suddenly shut off. Rapid rainfall deficits of 2" to 5" quickly piled up in southern Minnesota.
The result? Welcome to "Flash Drought 2.0." Now the National Drought Mitigation Center (yes there is such a beast) is reporting that Minnesota is the fastest growing drought area in the U.S. in August. The term "crop damage" has also crept into their reporting.
Simply put, we need rain. There are signs of a wetter pattern developing in Minnesota later this month. The question is will it come soon enough to avoid significant crop yield losses?
Minnesota's "Flash Drought 2.0" is fastest in the nation
In 30+ years of eyeballing weather patterns in Minnesota this is the fastest transition from drought-to flood-back to drought I can ever recall. Take a look at the data from the national Drought Mitigation Center. Minnesota leads the nation in plunging headlong into drought. We like to brag on Minnesota as a national leader in many categories. But not this one.
This map shows how Minnesota, Iowa, the eastern Dakotas and western Wisconsin are the epicenter of a rapidly deepening drought. "MPR Country" is drying out faster than anywhere in the nation.
Here's a look at the rapid rainfall deficits of 3" to 7" accumulated since late June in Minnesota.
Crop Damage Ahead?
Theres' some disturbing language in the NDMC report. It turns out our wet spring means root systems developed in a shallow zone in moist topsoil. Now "flash drought" has parched topsoil, and may be causing damage to fragile shallow crop root systems in the Upper Midwest.
Drought expanded in the central Midwest during August, harkening back to last summer when drought severely limited crop production and led to crop indemnity payments of $17.3 billion to the nation’s farmers. Concern for crops in the Midwest began as the cool, wet spring and flooding delayed planting. Crops developed shallow roots because there was plenty of moisture, so when the rain stopped falling in early July, the crops became stressed more quickly than they would have if they had deeper roots.
The heat, dwindling soil moisture and crop stress in the western Corn Belt led the U.S. Department of Agriculture to lower corn and soybean forecasts in its Aug. 12 report as crop damage continued in the Midwest. The corn production forecast was lowered to 13.763 billion bushels, down slightly from the 13.95 billion bushels forecast in July. The August soybean yield forecast fell substantially to 42.6 bushels per acre, compared to 44.5 bushels per acre in July. Soybean production was estimated to be 3,255 million bushels.
Wanted: Soaking rains
How much rain would it take to end a drought? We need a good widespread 2" to 5" over the region in the next few weeks. here's NOAA's "Palmer Index" which tracks rainfall needed to end drought.
The long range drought outlook at this point calls for "persistence."
The good news? There are signs of a potentially wetter pattern developing in the Upper Midwest after about September 18th. Here's NOAA's 16 day GFS output...which suggests some decent multi inch rainfall potential in about 10 days to 2 weeks.
NOAA's CPC paints chances for wetter than average conditions as we move into late September.
Will the wetter pattern be enough to erase our latest "flash drought?"