textproduct: Goodland

KEY MESSAGES

- A few severe storms are possible across eastern Colorado late this afternoon and evening, mainly between 5-10 pm MDT. Large hail, damaging winds and a brief tornado are possible.

- There is a 30% chance that several rounds of thunderstorms may lead to localized flooding in low lying areas and small streams tonight and early Friday morning.

SHORT TERM /THROUGH FRIDAY/

Issued at 1241 PM MDT Thu May 21 2026

Today, we have an approaching 500 mb low moving into the region from the northwest. Down at 850 mb, a low is strengthening as it come out of the Northern Rockies and a high over the mid- Mississippi River Valley work together to push ample moisture into the area. This is keeping us mostly cloudy to overcast all day, keeping temperatures capped out in the upper 50s and 60s. As the 500 mb low moves closer, additional vorticity will cause showers throughout the day, ahead of the main round of storms. There is a 25% chance that these showers throughout the day weaken the environment and storms this evening are not severe. The main round of storms looks to start forming near the western CWA border around 22-01Z in two segments. The southern segment looks to largely remain south of the CWA, but may briefly be a severe threat in Cheyenne county Colorado. The northern segment looks to form as isolated cells before morphing into more of a QLCS or cluster threat. When the storms are isolated, this will present the greatest potential for hail up to 2.5 inches and a strong tornado. However, there only looks to be 1-2 hours where isolated cells will dominate before they become a cluster or line. If the mode is more of a cluster, hail up around 1.5 inches and 60-70 MPH winds could become the main threat. If the storms become a QLCS, the threat for 70-80 MPH winds and brief spin-up tornadoes increase, but the hail threat decreases. The strongest storms look to be west of KS 27 and gradually weaken to the east, but there is a severe threat across the CWA with these storms. Peak intensity looks to occur between 0-6Z As mentioned before, the storms will persist overnight, weakening into widespread showers, lasting to around sunrise. Temperatures are forecast to cool into the 40s tonight, but may be closer to 50 depending on how high dewpoints remain. We are expecting the cold front associated with these lows to push in from the northwest around 8-10Z. Behind the cold front, expect winds to be from the northwest at 15 kts gusting to around 25-30 kts. Tomorrow, any lingering precipitation will be exiting by 15Z and winds throughout the morning will gradually be weakening. By the mid afternoon, a weak 850 mb high will be moving over the CWA, and the winds will slowing become more northerly, then northeasterly. Temperatures are forecast to warm into the 60s across the CWA. The high looks to remain over the CWA tomorrow night, staving off the bulk of any moisture return for most of the night. Temperatures under the mostly clear skies will drop to around 40, but if clouds do start moving in, temperatures may remain in the upper 40s.

LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/

Issued at 120 PM MDT Thu May 21 2026

***Synopsis***

Upper-level troughing looks to be moving through the forecast region Saturday. A surface low to the south of the forecast area is favored to establish a southerly return flow. This return feature may last through the end of the forecast period, as GEFS and EC ensemble guidance favor ridging overhead with troughing to the west beginning Sunday, and potentially lasting through the end of the forecast period. There are indications that southwesterly flow establishes itself overhead by Tuesday morning, which could allow some shortwave systems to traverse the area. GEFS guidance is more in favor with this solution than the EC, as the GEFS pushes the trough across the Western United States moves eastward faster. This may allow a cold front to cross the forecast region as early as Wednesday.

***Discussion***

The southerly return flow appears to favor warm and moist conditions throughout the long term period. Highs look to center themselves in the 70s and 80s. LREF guidance also suggests that dew points are favored in the 40s and 50s. Troughing setting up to the west may support multiple days of precipitation to occur, especially if southwesterly upper-level flow can eject shortwave systems into the area. Ensemble guidance is consistent on Sunday-Thursday having potential for over 1000 J/kg of CAPE (a measure of atmospheric instability). This could support thunderstorm development each day. However, LREF mean 500-mb winds are not expected to get much higher than 25 kts, which would indicate a marginal severe potential at best for these thunderstorms. NBM guidance suggests that the greatest opportunity for precipitation to occur is on Wednesday and Thursday, where there are wide zones of 30-45% chances of greater than 0.1 inches of precipitation across the area. This may be associated with a faster progression of the trough eastward toward the forecast region, enhancing how many thunderstorms are able to develop. Even so, the amount of precipitation any one location receives will be dependent on where storms track. Light showers to weak thunderstorms appear to be the most likely scenario at this time for the long term. One final point to add is that critical fire weather appears to be a minimal threat. The one exception to this may be on Tuesday, not because relative humidity values are low, but because wind gusts may reach the 40-45 mph range. If this occurs, existing fires may be capable of spreading rapidly. Otherwise, hazards look to be kept to a minimum next week.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1135 AM MDT Thu May 21 2026

Conditions at KGLD and KMCK are forecast to bounce between IFR and MVFR all day as stratus and showers move through the region. Late this afternoon and through the night, heavier showers and storms are expected to move through. Minimums may be met in the 9-14Z time frame, but theres no strong sign that conditions will be that bad.

GLD WATCHES/WARNINGS/ADVISORIES

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