I Wish it Would Rain Down

The general synoptic pattern over the next week will feature an amplified pattern with troughing off the Pacific Northwest, ridging across the southwestern U.S., and a trough over the Great Lakes. That pattern will keep Nebraska under west-northwest flow for much of the week. Embedded shortwaves in that flow will help bring chances for showers and storms at various points in time over the next week.

At the moment, there appears to be a good chance for showers and thunderstorms across central Nebraska on Saturday night, Aug. 17, with a chance they make their way over toward Norfolk, Columbus and Seward. Chances for storms are highest across western sections of the state Sunday, Aug. 18 and Monday, Aug. 19, across the central and eastern sections of the state on Tuesday night, Aug. 20, and across eastern Nebraska on Friday, Aug. 23. Some areas could stand to pick up additional beneficial precipitation next week, but after Friday, things may be pretty dry across the state for the following five to seven days as the ridge builds north and east.

Figure 1. Weather Prediction Center projected precipitation for next week through Thursday, Aug. 22.

Figure 2. Ridge sandwich: Average 500-mb height pattern next week.

Figure 3. Projected temperature anomalies.

Seasonal Temperatures, But Heat is Coming

Temperatures next week will be seasonal highs, mostly in the 80s and possibly low 90s by Saturday, Aug. 24, though any lingering convection or cloud cover could keep temperatures down in the 70s. Temperatures will generally be a bit cooler earlier in the week than later in the week, especially in eastern Nebraska where an early week cold front will bring in another shot of cooler and slightly drier air to start to the week. Overnight lows are likely to be elevated in the second half of the week as it will be humid. All in all, nothing too atypical for August, but the warm low temperatures should lead to next week being a bit over climatological norms overall for most of the state.

The real heat may be coming the week after next as the ECMWF AI is suggesting chances for that southern ridge to build north and bring a few days of intense heat to the Central Plains and western Corn Belt. Triple-digit heat may not be done with areas of western and southern Nebraska just yet. The CPC is in agreement with it being above average in the eight- 14-day period and the worst of the heat is possibly just beyond that.

Figure 4. Eight- to 14-day temperature outlook from the CPC.

Figure 5. Eight- to 14-day precipitation outlook from the CPC.

Beneficial Moisture

The past week has been generous to much of the southern Panhandle and southwestern Nebraska, where most places have received over an inch and several locations have picked up over two inches. Not all of this soaked in (perhaps not even a majority in some cases) but it was still very welcomed moisture in an area that had been pretty dry over the previous several weeks. The Highway 30 corridor from Columbus to the Omaha metro area also picked up 1.5 to four inches of rain over the past several days, with some locations in Sarpy County closing in on five inches since Sunday evening. Other areas in eastern Nebraska picked up between half an inch and inch between Sunday night and last night. Exception is parts of southeast Nebraska (e.g., around Beatrice) where some locations had less than a 0.10-inch and are seeing rainfall deficits start to accumulate again. The Highway 136 corridor between Fairbury and Johnson is an area to watch for flash drought if rain doesn't materialize soon.

Figure 6. Seven-day precipitation totals.

Figure 7. Temperature ranks for the period of Aug. 7-13.

Coolest August Week on Record

After a very warm start to the month with record heat in the Panhandle, temperatures dropped sharply in central and eastern Nebraska Aug. 6 and then later in the week in western Nebraska. In fact, the previous seven days featured the coolest average temperature for the common period on record (Aug. 7-13) for the central, south-central, east-central, and southeast climate divisions. Temperatures were especially cool across the state Aug. 9, with some areas in the western Panhandle not getting out of the 50s and much of central Nebraska spending the weekend socked in with clouds and maximum temperatures in the 60s. Overnight lows dipped into the upper 40s and low 50s the morning of Aug. 9 and into the mid-50s on the mornings of Aug. 10 and 11 in the eastern side of the state. Combined with maximum temperatures staying in the low to mid-70s for several days, average temperatures were in the mid-60s for several days.

The cooler weather has set heat unit accumulation back, and parts of central and northeast Nebraska are getting close to being behind the curve on GDDs or heat units. This isn't necessarily a cause for concern though, given the heat that is likely to be present later in the month.

Figure 8. Soil moisture percentiles from SPoRT LIS.

Figure 9. Four-inch bare soil temperatures.

Temperature and Precipitation Summaries

This document contains the maximum/minimum temperature, average temperature, number of days with maximum temperatures ≥95F, minimum temperatures ≥70F, degree days, and total precipitation for each Mesonet station over the period from Aug. 4-10.

Below are the temperature and precipitation extremes around the state over the past week:

• Maximum Daily High Temperature: 96°F, Scottsbluff 1E
• Minimum Daily High Temperature: 54°F, Bushnell 15S
• Minimum Daily Low Temperature: 45°F, Springview 2 NW
• Maximum Daily Low Temperature: 67°F, Falls City Brenner Field
• Maximum Weekly Precipitation: 2.99 inches, Champion 2.6 SW
• Minimum Precipitation: 0.00, multiple locations