April 2008 Climate Summary

Region Breakdown

Dryness was present over the western two thrids of the High Plains region for the month of April 2008. Areas in the eastern third of the region improved significantly with respect to March. Snow fell in the western Dakotas and in Western Nebraska and in the mountainous states of Wyoming and Colorado while much of the east and southeast portions of the region received mostly rainfall. Several stations in the western part of the region received a tenth of one inch of precipitation or less while stations in southeast Kansas received 5-8 inches of precipitation. The percent of normal map shows that a few parts of the region were above 100% and some areas approached 200% of the normal precipitation for the 30 year period 1971-2000.

Weather patterns consisted of a series of high and low pressure systems, each moving through the region in a manner of a few days. The intermittent cold fronts moving generally down from the north and the warm fronts moving mostly up from the south caused temperatures to fluctuate considerably during the month. The cold warm air fluctuation is not uncommon for the spring transition months, but the frequency of changes was fairly high.

The average temperature patterns warmed over the region and the pattern is typical for this time of year with the coldest temperatures to the north and the warmest temperature to the south. The exception is in the mountains where the average temperatures were the lowest owing to the decrease in temperature with elevation.

The temperature average for April was below the mean temperature for the normal period 1971-2000 over much of the region with a range from 0 to nearly 8 degrees below average for the month. A few stations in Colorado and Kansas experienced temperatures 0-2 degress above the monthly normal.

A weekly average soil temperature of 50 or higher is recommended before planting of corm. Soil temperatures have been slow to warm this spring. Average weekly soil temperatures at the 4 inch depth have reached 50-60 degrees over most of Nebraska, Kansas, Eastern Colorado and Eastern Wyoming.

The heating degree days (HDD) were below normal in some areas in the western part of the region but were up to 200 HDD above the normal accumulated values for most of the rest of the region. Thus energy required to heat homes and businesses was higher than usual for most of the region in the month of April.

Climate Outlook

Forecasts generally indicate La Nina conditions for May-April-June 2008, followed by significant uncertainty thereafter. The temperature outlook for May-June-July is for above normal temperatures in Western Wyoming and Colorado with chances of above reaching up to 50% skill level relatvie to a 33% by chance alone.

Drought Watch

Drought conditions vary from D0-D3 in the region where the extreme drought (D3) is in the western part of North Dakota and Nebraska. The seasonal outlook through July is calling for some improvement in these areas.