March 22, 2013

The March 19 U.S. Drought Monitor shows a one-category improvement from Exceptional (D4) to Extreme (D3) conditions for a small portion of eastern and north central Nebraska. The largest improvement was in an area east of Clay Center to Albion and south of a line from Columbus to West Point. This area benefitted from a combined rain/snow storm March 9-10.

The second widespread area of improvement was north of a line from Gordon to Ainsworth where several recent snows have improved top soil moisture. Soil moisture monitoring sites operated by the High Plains Regional Climate Center now indicate that field capacity has been reached at the 12-inch depth in the area designated as D3. It should be noted that the primary soil type in this region is sand and that field capacity would be 1 inch of available moisture.

Drought conditions were also degraded in the central Platte River valley for counties adjacent to the south side of the river between Kearney and Grand Island. After an examination of soil moisture values in this region, it was deemed that the Drought Monitor authors had been too aggressive in their depiction of the impacts of recent storm activity.

Although there was a return to D4 conditions in this region, additional storm activity in the next few weeks will likely return this area to D3 conditions. Since the drought has been firmly established for more than 18 months, soil moisture will be the most significant criteria in determining when D4 conditions are reduced to D3.

I and other Drought Monitor contributors in Nebraska have recommended that areas in the remaining D4 area should be improved to D3 conditions once field capacity has been reached at 1 foot. This would signify that 20% of the top five feet of the profile has reached field capacity. It should be noted that almost all soil moisture monitoring sites in the state are lower than they were at the same time last year. In addition, soil moisture depletion was already initiated at this time last year due to excessively warm temperatures that resulted in rapid green-up of grasses and trees.

Models indicate a high probability of below normal temperatures through the end of the month. It also appears that a significant snow event will materialize in the central Plains this weekend, with northern Kansas and Nebraska likely to be at the center of this activity. Projected water equivalent moisture for this storm across the southern half of the state is 0.50-0.75 inches.

Another system is projected to roll into the region at the end of the month and bring additional moisture to the region. It is too early to tell the exact storm track of this system, but early indications are that some areas could receive over an inch of moisture. A return to more spring like warmth is expected across the central Plains the first week of April.

If both of the projected storm systems materialize over the next 10 days, it is likely that most, if not all of the D4 areas will disappear in Nebraska. Unfortunately, the hydrological drought signal will likely remain with us through this growing season.

Al Dutcher
Extension State Climatologist