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Abstract. Flash droughts tend to be disproportionately destructive because theyintensify rapidly and are difficult to prepare for. We demonstrate that the2017 US Northern Great Plains (NGP) flash drought was preceded by abreakdown of land–atmosphere coupling. Severe drought conditions in the NGPwere first identified by drought monitors in late May 2017 and rapidlyprogressed to exceptional drought in July. The likelihood of convectiveprecipitation in May 2017 in northeastern Montana, however, resembled that ofa typical August when rain is unlikely. Based on the lower tropospherichumidity index (HI_low), convective rain was suppressed by theatmosphere on nearly 50% of days during March in NE Montana and centralNorth Dakota, compared to 30% during a normal year. Micrometeorologicalvariables, including potential evapotranspiration (ET_p), were neither anomalouslyhigh nor low before the onset of drought. Incorporating convective likelihoodto drought forecasts would have noted that convective precipitation in theNGP was anomalously unlikely during the early growing season of 2017. It maytherefore be useful to do so in regions that rely on convectiveprecipitation.