textproduct: Goodland

KEY MESSAGES

- A few severe storms capable of producing 2" diameter hail and 70 mph winds are possible this afternoon and evening, mainly between 2-9 PM MDT / 3-10 pm CDT.

- Locations that received heavy rain during the past 24-hr are more prone to experience flash flooding, should additional heavy rain occur this afternoon.

- A few severe storms capable of producing 2" diameter hail and 70 mph wind gusts are possible, yet again, during the afternoon and evening hours on both Monday and Tuesday.

SHORT TERM /THROUGH MONDAY/

Issued at 1255 AM MDT Sun Jun 21 2026

Overview: WNW flow aloft will prevail over the Tri-State Area.. on the NNE periphery of an amplifying upper level ridge over northern Mexico, the Desert Southwest and Southern Plains. Small amplitude shortwave energy over southeast Wyoming at 08Z this morning (refer to SPC mesoanalysis 400-250 mb Pot Vort) will track ESE over far northeast Colorado and northwest Kansas this afternoon. Similar small amplitude shortwave energy progged to move ashore northern California today will progress ESE across the central Rockies and adjoining High Plains Monday afternoon.

This Morning: Ongoing storms at 3 am CDT will produce locally heavy rainfall in Gove/Graham counties prior to exiting the Goodland county warning area ~4 AM CDT. Severe weather is not expected early this morning.

Today: Widespread convection Sat aft-eve and early this morning has, no doubt, decreased the potency of the thermodynamic environment in place over the region. Nevertheless, ample low- level moisture and a renewed elevated mixed layer (700-500 mb lapse rates ~8 C/km) will still foster moderate diurnal destabilization (1500-2000 J/kg MLCAPE) this afternoon. That's right. On the High Plains, the atmosphere finds a way. Convection allowing guidance continues to suggest that low- level convergence along an inverted surface trough in northeast CO.. and DPVA with the aforementioned shortwave energy.. will facilitate isolated to scattered convective development during the early-mid afternoon, beginning ~2-3p MDT (20-21Z). With moderate instability and 50+ knots of effective deep layer shear, a few supercells capable of producing large hail and damaging winds are possible. Virtually all guidance indicates weak low-level flow and light winds this afternoon, suggesting that.. environmental conditions are not particularly conducive for tornadoes. Expect highs in the lower 80's to lower 90's.

Hydrology: Heavy rainfall occurred over much of the Tri-State Area Saturday aft-eve and very early this morning. As much as 3 to 7.5 inches of rain was observed over portions of Rawlins and Decatur counties, where a Flood Warning remains in effect until 4 PM CDT. Locally heavy rainfall can be expected with any thunderstorms this afternoon. While reduced thunderstorm coverage and longevity today (compared to Saturday) will pose a lower overall risk for flooding, locations that received heavy rainfall during the past 24-hr are more prone to experience flash flooding, should additional heavy rain occur this afternoon.

Monday: With little change in the synoptic pattern and another small amplitude wave in WNW flow aloft progged to traverse the region during the afternoon, expect sensible weather conditions (and severe weather potential) similar to today.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/

Issued at 135 PM MDT Sat Jun 20 2026

***Monday-Wednesday***

Thunderstorms are in the forecast Monday through Wednesday. A 500-mb trough traversing the Northern United States and Southern Canada along with a shortwave ridge over the forecast region looks to produce a surface low pressure across portions of Colorado Monday. A convergence zone would be favored to develop somewhere near Colorado's eastern border, though its exact location and timing of formation is in question. Most LREF solutions suggest that this convergence zone will be associated with around 1200 J/kg of surface- based CAPE (a measure of atmospheric instability) or less, though higher-end scenarios could see up to around 2000 J/kg. At the same time a 500-mb jet streak at the base of the trough looks to be strengthening during the afternoon and evening hours. GFS and EC model soundings indicate that this development could support 0-6 km vertical wind shear of 35-60 kts along the convergence boundary. Storms may be allowed to become severe under this scenario. While all hazards may be possible with this setup, this may need to be refined as we get closer to the event, as thunderstorms in the short term may modify the environment significantly before then.

The risk for thunderstorms continue Tuesday. 850-mb GEFS guidance still shows a low across portions of Colorado, at the same time that the 500-mb trough from Monday moves overhead. This would produce another zone of convergence across the CWA where northerly and southerly surface winds meet. In addition, the 500-mb jet streak looks to remain in place. This pattern may linger into Wednesday afternoon and evening as well. Surface- based CAPE values may be allowed to get a little higher on Tuesday and Wednesday than Monday, as portions of Eastern Colorado and Northwest Kansas have greater than a 50% chance to see over 1000 J/kg based on LREF guidance. Severe thunderstorms would continue to be possible as vertical shear provided by the upper-level jet remains in place. For each day Monday through Wednesday, confidence is around 10-15% in severe thunderstorms occurring.

***Thursday-Saturday***

GEFS and EC 500-mb height mean-spread guidance is consistent with ridging moving in overhead Thursday and Friday. This could promote warmer temperatures going into the weekend. Highs are currently in the mid 70s to lower 80s Thursday, lower to upper 80s on Friday, and lower to mid 90s on Saturday. Thunderstorm potential may still continue Thursday and Friday, though is a lot more uncertain than Monday through Wednesday. If and when thunderstorms occur is contingent on the presence and timing of upper-level shortwave troughs embedded in the ridge. GFS and EC deterministic guidance does show that these features may be present. Confidence is increasing in the presence of these shortwaves on Thursday, as NBM 24-hr precipitation guidance shows that most of the area has a 50- 70% chance of seeing greater than 0.1 inches of precipitation. This confidence decreases Friday, as the same guidance shows at best a 1 in 3 chance for greater than 0.1 inches of precipitation across nearly the entire area. The thunderstorm risk appears to diminish almost entirely by Saturday as ridging takes full affect. Forecast guidance does indicate relative humidities dropping into the teens in portions of Eastern Colorado Saturday afternoon. As such, the potential development of critical fire weather conditions on Saturday is something to keep an eye on as we approach next weekend.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 445 AM MDT Sun Jun 21 2026

GLD: LIFR to VLIFR ceilings will persist through sunrise. Ceilings will lift and scatter to VFR by mid-late morning (~15Z). Aside from sub-VFR conditions associated with yet another round of thunderstorms this afternoon (~22-01Z), VFR conditions will otherwise prevail during the afternoon and evening. Light (~10 knot) N to E winds will prevail through the majority of the TAF period. Gusty and erratic winds can be expected in vicinity of any storms.

MCK: MVFR to IFR ceilings are expected through sunrise. Ceilings will lift and scatter to VFR by mid-late morning (~15Z). Aside from a potential for sub-VFR conditions assoc/w yet another round of thunderstorms this afternoon (~22-02Z), VFR conditions will otherwise prevail during the afternoon and evening. Light (~10 knot) N to E winds will prevail through the majority of the TAF period. Gusty and erratic winds can be expected in vicinity of any storms.

GLD WATCHES/WARNINGS/ADVISORIES

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