Southwest Great Plains Drought Beginning

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The NOAA/CPC monthly drought outlook for the U.S. indicates the Upper Midwest U.S. drought eases in September. However, the southwest Great Plains observes developing drought conditions. The GFS (model) is quite dry and exceptionally hot for the first half of September in the southwest/south Great Plains.

Highlight: U.S. loses one drought area (Upper Midwest), gains another (southwest Great Plains).

Fig. 1: NOAA/CPC monthly drought outlook valid for September 2021.

Discussion: Drought in the Upper Midwest/West Corn Belt eases in September according to NOAA (Fig. 1). The influence of the tropics on the mid-latitude weather pattern changes! The new drought (and heat) risk is across the wheat-growing areas of the west and southwest Great Plains. The GFS indicates hot weather in this zone through the weekend despite the much cooler regime to the east (Fig. 2). The boundary between the two air masses focuses heavy rain on Kansas. In the 6-10-period the central and southern Great Plains observe little or no rainfall and according to the GFS record heat risk (Fig. 3). In the 11-15-day period the hot weather is hotter and more expansive (Fig. 4). The GFS 15-day forecast offers rainfall in Kansas – all short-term (Fig. 5). Otherwise, a robust dry pattern for Kansas to Oklahoma. The Upper Midwest is showery where drought eases.

Fig. 2-5: GFS days 1-15 temperature anomaly sequence and 15-day rainfall forecast.