July 26, 2012

Week to End with Cooler Temps; Rain Possible Next Week

Slightly cooler weather moved into Nebraska mid-week as a cold front moved southeast from the northern Plains. Unfortunately, thunderstorm development along the cold front was spotty and most locations were left dry. Pockets of 0.50 to 1.50 inches of moisture were reported, but they were primarily confined to south central, central, and southeast Nebraska.

Unfortunately, the previous week’s heat was unrelenting and agricultural crops statewide have continued to deteriorate. Nebraska Agricultural Statistics rated only 9% of the dryland corn crop good to excellent as of Sunday. This doesn’t reflect the three days of 100+ F high temperatures recorded Monday through Wednesday.

Drought Expands

The latest U.S. Drought Monitor has expanded extreme drought conditions (D3) into northeast Nebraska, while east central and southeast Nebraska are depicted as experiencing severe drought (D2) conditions. Further expansion of D3 conditions into eastern Nebraska is likely in the absence of widespread rainfall prior to next Tuesday’s Drought Monitor deadline.

The U.S. Drought Monitor classifies D3 conditions when an area experiences 50% yield reductions to the primary agricultural crop in the area of interest. Exceptional drought (D4) conditions require a 70% reduction, while D2 conditions begin when yield reductions hit 30%. Reductions in drought classes are considered when precipitation exceeds 200% of normal during the seven days preceding the Drought Monitor reporting cutoff.

There's Hope in the Forecast

Looking forward, models are more aggressively indicating opportunities for moisture across Nebraska during the next week. As the ridge rebuilds back into the central Plains, it will force a warm front northward and bring thunderstorm chances to eastern Nebraska. Additional rain chances are indicated during the first half of next week as monsoon moisture works around the periphery of the ridge.

It should be noted that the models do not project a widespread rain event, but do indicate daily chances (20-30%) of rain. Depending on the model, temperatures are likely to visit the century mark across portions of southwest and south central Nebraska early in the week. If the heat fails to build that far north, it would be supportive of more widespread convection chances as monsoon moisture interacts with energy moving on the ridges periphery.

The overall precipitation scenario is not promising, but at least several reasonable chances exist during the next week. Unfortunately, models firmly rebuild the ridge into the central Plains during the second half of next week. If this ridging forecast materializes, most of the state will return to high temperatures in the upper 90s to 105°F during the first week of August.

Al Dutcher
Extension State Climatologist