Quick Overview: Crops are reaching peak ET, and with the recent dry spell for many people in Nebraska, soil moisture monitoring and irrigation is at an important stage. The recent cool weather has limited the atmospheric demand component to ET, but the forecast is telling us that this will change. Temperatures will climb into the upper 80s this weekend and into the mid 90s next week. Precipitation chances remain small, if not non-existent, for most of Nebraska for the next week. Small thunderstorms may develop, but the ridge of high pressure and upper level northwest flow will limit any valuable accumulations.
The trough centered over the Great Lakes is the predominant feature in 7-14 day weather forecasting models. Shortwaves running around the trough look to bring a few disturbances and cooler temperatures to Nebraska, but will primarily affect Eastern and Northeast Nebraska. The location of this trough and strength of the shortwaves may have a profound impact on temperature prediction in the state. With that said, the weather pattern is looking like it will remain summer-like (warm and dry) through the end of July.
The Three-Month Outlook from the CPC, which covers August, September, and October have increased odds for below normal temperatures for the Northern Plains with high confidence in below normal temperatures for Nebraska. They also have a large area of the U.S. in the area of increased odds of above normal precipitation for the 3-month period. This area runs from Southern California, north and east to Wyoming and Nebraska, and down to western Texas. They are expecting the monsoon conditions over the 4-corners region to be the dominant feature in the upcoming months. These conditions are typical with an El Nino, which is still being predicted for this fall and winter. What this means for farmers is a potentially delayed harvest with cooler and wetter than normal conditions; however, I have not seen the data on a correlation of an El Nino and an early frost. It is still way too early to predict the potential first frost (I don’t want to think about frost just yet).
After our cool down this week, we will return to our typical summer time weather pattern. The cool down will arrive when a large portion of the corn crop is pollinating, but we will warm up by the weekend. Temperatures should be fairly moderate with highs in the upper 80s and some low 90s by the beginning of next week. Some models show some cool air trying to push back in from the north by the middle to end of next week, but we will wait and see if they continue that trend.
The weather pattern is about to change, and it may stick around for a while. A big push of cool air will come down into the corn belt next week and the 6-10 day and 8-14 day outlooks have the below normal temperatures sticking around. Average high temperatures in July are in the lower 90's for southern NE and upper 80's for northern Nebraska, so we will be 10-15 degrees below normal for a few days with temperatures gradually warming up. The state will start to warm up from west to east as the system slowly moves east.
This is a day late, but here is the latest drought monitor for the High Plains region. Nebraska remained the same as last week, as most of the High Plains had very little change. There was a slight increase in D1 and D4 coverage area in South Central and Southeast Colorado.
Here is the latest Drought Monitor released this morning. There was another gradual shrinking of the drought coverage area in Nebraska this week, with significant improvement in SW portions of the state. The second map below is the 30 Day SPI (Standardized Precipitation Index) and this is a drought tool that focuses on precipitation. The SPI is often a good indicator for the early detection of drought conditions during the growing season. The latest 30 Day SPI shows abnormal dryness in the Panhandle, so this is an area to keep an eye on and probably won't be picked up by the drought monitor unless dry conditions and warm temperatures persist. The long-term forecasts for this part of the state are predicting average temperatures will be below normal with above normal precipitation for the next 3-month period.
The graphs below show two climate variables (precipitation and growing degree days) compared to the county average corn yield for the corresponding year. The graphs are for four sites in Nebraska: Ainsworth, Scottsbluff, Holdrege, and Lincoln. The precipitation and GDD data are plotted for individual monthly amounts for April through October for each year. The 2014 points are for the April, May, and June accumulations of precipitation and GDDs. These graphs were created using the Ag Climate View Tool from the Useful 2 Usable project. County corn yield data is a combination of irrigated and non-irrigated fields.
I study weather and climate impacts on agriculture, climate variability, and using weather and climate information to make better agricultural decisions.