DISCUSSION
Issued at 349 AM CDT Sat Jul 27 2024

The forecast begins with an upper ridge over the Great Lakes and a closed upper low over eastern Kansas and Oklahoma. Temperatures will range from the low 90s for areas along and north of a line from Cozad to Holdrege to Hebron. Areas south of this line can expect temperatures in the low to mid-90s. Some lingering haze may still be possible today, as the HRRR near surface and vertically integrated smoke models are showing some. The good news is that there should be less haze than the past several days.

A surface trough on the lee side of the Rockies will be the main driving force of any convection in the area today. SBCAPE and MUCAPE values of around 1500 J/kg in the western part of the state and the extreme western portion of the Hastings CWA is possible. A few isolated thunderstorms may develop initially in western Nebraska, northwestern Kansas, and Colorado. These storms are expected to move into the Hastings CWA after sunset. The extreme western portion of Dawson County is outlooked in a Marginal Risk for severe weather by the Storm Prediction Center. This is where instability is best for our area. As storms move east across the area tonight, the potential for severe weather is expected to decrease. Thunderstorms should be over for most areas by sunrise Sunday morning.

Zonal flow sets up over the area Sunday, with the main upper ridge continuing to move northeast, to the north of New England. A weak upper ridge sets up over the Front Range, with an upper trough over Big Sky Country (Montana) and the West River portion of South Dakota. Temperatures have trended down slightly, with highs now expected to be in the low to mid-90s for areas along and north of a line from Cozad to Holdrege to Hebron Nebraska. Areas south of this line are expected to have temperatures reach the upper 90s to around 100 degrees. heat index values approaching 99-103 degrees will be possible in those areas. No heat related products are in effect at this time, but will need to continue to monitor the souther portions of the area.

There is a chance (20-30%) of thunderstorms Sunday afternoon and evening, a few of which could become strong to marginally severe.
The main concerns with any storms that develop would be hail, wind, and moderate rainfall.

The upper ridge moves further over the Central High Plains and Great Plains Monday through Wednesday. Expect a gradual warming trend Monday and Tuesday. At this time, Tuesday and Wednesday appear to be the hottest days of the forecast period with highs ranging from the mid-90s to around 105 each day. Widespread heat index values of 100+ are expected both days, with many areas approaching or exceeding advisory criteria (105 degrees). It is still a little early to issue anything, so we will continue to monitor the forecast over the coming days. Periodic shower and thunderstorm chances (10-30%) will be possible Tuesday and Wednesday evenings.

A little more uncertainty comes into the forecast Thursday onward.
Models are showing the possibility of an upper trough moving through the area, but with timing and location variable depending on the model. Slightly cooler temperatures are expected with most areas returning to the 90s for highs.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
Issued at 631 AM CDT Sat Jul 27 2024

For KGRI/KEAR Airports:

VFR conditions persist through the forecast period at both terminals. Winds will be out of the south today, increasing to around 15-20kts by 17Z. Winds are expected to decrease overnight. Lingering haze will continue in the region with little impact to visibility. A few isolated storms may be possible this evening into tomorrow morning; however, confidence in timing and location is low at this time.

GID WATCHES/WARNINGS/ADVISORIES
NE...None.
KS...None.