textproduct: Goodland

KEY MESSAGES

- Severe chances continue through the end of the week. Coverage will be somewhat limited by weak forcing, but environmental parameters support at least a marginal risk of severe storms each day with damaging winds and large hail the main hazards. A few supercells will be possible Wednesday and Thursday with increasing wind shear, which could also produce brief tornadoes.

- Near normal temperatures through Wednesday, then above normal for the end of the week.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 100 PM MDT Tue Aug 18 2026

Shortwave trough rotating around the Four Corners ridge will result in thunderstorm chances tonight. CAMs show initiation occurring in northeast Colorado by around 02z and quickly spreading east into areas generally north of Interstate 70 through 04z with additional lift provided by a southwesterly low level jet. Instability will initially be limited, resulting in mostly high-based updrafts and a wind threat, but as they move further east MUCAPE rapidly increases to 1500-2500 j/kg in Kansas and Nebraska. Deep layer shear will be around 50 kts. So, in addition to the wind threat, clustering storms may also pose a large hail threat through the late evening and overnight hours. Surface-based CIN appears too high to support a tornado threat as storms will likely be elevated. CAMs show storms gradually weakening after about 09z as they continue to move east.

Ridge begins to amplify on Wednesday over the Great Basin and western Rockies. Appears to be another embedded wave in the northwest flow over the plains which initiates convection in northeast Colorado around 22z. REFS shows generally weak instability of up to 1500 j/kg, but there are pockets of stronger instability of up to 2500 j/kg generally south of Interstate 70. Deep layer shear is excellent in the northwest flow at around 45 kts. The environment would be supportive of supercells capable of large hail, damaging winds and perhaps a tornado. Coverage may be somewhat limited by the relatively weak forcing, but best chances appear they will be south of Interstate 70 through the evening hours.

Upper ridge continues to strengthen Thursday over the Great Basin. Instability is similar to Wednesday afternoon, but with a slight decrease in deep layer shear to around 35 kts with the stronger ridge. Should see another shortwave trough moving through in the afternoon and evening with widely scattered thunderstorms developing. NBM currently shows best chances east of Highway 25 in Kansas and Nebraska through about 06z before moving east and out of the area.

The ridge continues to dominate on Friday, but with a notable shift eastward and centered over Colorado. Nonetheless, eastern parts of the area, generally east of Highway 25, will once again see weak to moderate instability develop and 30-50 kts of deep layer shear on the eastern periphery of the ridge. Assuming some kind of embedded wave rotation around the ridge, will see some low chances for afternoon and evening thunderstorms in those areas.

Temperature trends for the period are near normal tomorrow, but warm to above normal for both Thursday and Friday as the ridge builds.

LONG TERM /SATURDAY THROUGH TUESDAY/

Issued at 225 PM MDT Tue Aug 18 2026

Ensemble guidance continues to be in support of ridging at 500-mb overhead through the duration of the long term period. At the same time, a 500-mb shortwave trough looks to be traveling anticyclonically around the ridge, with a high amplitude 850-mb trough at its leading edge. There are indications that a surface low will be able to form across the High Plains in association with this 850-mb feature, and move over or just south of the forecast region Saturday and Sunday.

***Saturday/Sunday***

Southerly flow underneath the ridge alongside solar heating looks to favor hot conditions Saturday and Sunday, with highs forecast in the mid to upper 90s, and possibly low 100s in some spots. In addition, GEFS 850-mb height guidance is in support of a high across portions of Eastern Texas during this period, which would prevent moisture from entering the southerly return flow. This is expected to promote dry conditions across portions of East-Central Colorado and West- Central Kansas, where relative humidities (RH) may drop into the lower 20s to upper teens. While RH values are forecast to be a bit low, fire weather conditions are not yet expected either Saturday or Sunday, as wind gusts are not favored to exceed 25 mph except in Kit Carson and Yuma Counties in Colorado, where wind gusts may reach the 25-30 mph range. Still, LREF guidance shows that RH values have less than a 20% chance of meeting criteria for critical fire weather conditions (less than 15% RH) across nearly the entire forecast area. Confidence in a Red Flag Warning being needed is less than 5% both Saturday and Sunday.

Forecast guidance continues to suggest that showers and thunderstorms are also possible during this period in association with convergence from the surface low pressure. Even so, NBM 24 hr precipitation guidance shows a 1 in 3 chance or less across the forecast area both days for greater than 0.1 inches of precipitation to be experienced. Any storms that develop are not expected to be severe, as LREF guidance shows a 2 in 3 chance or better that sfc- 500mb wind shear will be below 30 kts. Currently, the greatest concern with these showers is that they may be able to produce dry lightning, particularly across East-Central Colorado where RH values are lowest, and NBM guidance shows the highest chances of showers occurring.

***Monday/Tuesday***

As the surface low moves well south of the forecast area, a weak cold front may lower temperatures a couple of degrees into the low to mid 90s. Chances for precipitation increase a little bit during this period, especially on Monday when NBM 24 hr precipitation guidance shows a 40-60% chance of receiving greater than 0.1 inches of rain across portions of Eastern Colorado. This would be in association with a cold front. The risk for severe storms continues to be low, as LREF guidance shows similar probabilities for wind shear as Saturday and Sunday. RH values look to improve as well, as temperatures drop a little, and easterly winds across portions of Central and East Kansas feed slightly higher dew points into the forecast area. This would reduce risks for critical fire weather.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1119 AM MDT Tue Aug 18 2026

VFR expected to prevail at both KGLD and KMCK through this afternoon. Tonight, scattered thunderstorms will move across the area. There is about a 30% probability of brief impacts to either terminal, including gusty winds and visibility reductions in rain. The threat for thunderstorms will end by around 12z Wednesday morning.

GLD WATCHES/WARNINGS/ADVISORIES

KS...None. CO...None. NE...None.