Ag Weather Forum

Precipitation Forecast Caution

Bryce Anderson
By  Bryce Anderson , Ag Meteorologist Emeritus
Connect with Bryce:
DTN's seven-day total precipitation forecast shows much lighter amounts are expected than the NOAA quantitative precipitation forecast chart. (DTN graphic)

A notable difference in rainfall forecast amounts is indicated going into the last half of June. The Quantitative Precipitation Forecast (QPF) chart from the National Oceanic and Atmospheric Administration (NOAA) suggests rainfall totals over the time period ending Friday, June 22 in the range of 2 to more than 4 inches from south-central Kansas west to central Colorado and north to northern Minnesota, including more than an inch in southeastern Iowa, northern Missouri, and northern Illinois, along with the Texas and Oklahoma Panhandles.

DTN's rainfall total forecast for the same time frame, however, is for overall less rainfall, and more scattered occurrences of heavy amounts. The DTN forecast places heavy rain of over 2 inches only in portions of northern Colorado and southeastern Minnesota. Overall, the DTN presentation is more of the 1/2- to 1 1/2-inch range; and, in a notably drier area of northern Missouri, mostly 1/4 inch.

The reason for the difference in precipitation amounts likely is due to the DTN forecast incorporating a forecast model blend that uses input from both the U.S. Global Forecast System (GFS) model and the European weather model (ECMWF). The DTN forecast rainfall look for this particular event focuses the heavier rainfall activity in the western Plains-northern Midwest corridor, which is in line with forecast air mass boundary placement for next week.

How much rain, and when it develops, will be closely monitored, because of some hot weather indicated for the Midwest during this mid-June weekend. Exhausting heat that has parked over the Southern Plains for a number of weeks shows a move east and northeast for a few days, bringing temperatures in the middle to upper 90s Fahrenheit eastward across the Mississippi River. This kind of heat can stress crops in a short order, even though the soil moisture supply is considered to be generally adequate for corn and soybeans to withstand this hotter period. As of June 15, the heat wave was indicated to relent by June 19.

Another wrinkle in the rainfall forecast is any prospective moisture added into at least the southwestern U.S. from former Hurricane Bud, which entered the Baja California peninsula June 14. However, Bud-related precipitation appears to be limited to only portions of the southwestern U.S., in parts of Arizona and New Mexico, before the energy from this tropical system fully dissipates. Both the DTN and NOAA forecast precipitation totals have only slight easing of the harsh southwestern U.S. drought during this mid-June timeframe.

Bryce Anderson can be reached at

Follow Bryce Anderson on Twitter @BAndersonDTN



To comment, please Log In or Join our Community .