textproduct: Cheyenne

KEY MESSAGES

- Showers and severe weather return this afternoon, with further disturbances bringing a more active pattern through early next week.

- Somewhat drier air will move into the forecast area for Tuesday and Wednesday of next week, producing a decrease in areal shower and thunderstorm coverage, along with bringing a warming trend, though latest guidance does indicate the ridge may break down a bit and allow for more precipitation incursions.

SHORT TERM /THROUGH TONIGHT/

Issued at 202 AM MDT Sat Jun 20 2026

Lets get it on! Today will mark the start of an active weather pattern that will bleed into next week. So, lets take a closer look at this afternoon as we have and continue to anticipate the return of severe weather. Why today, well, a surface low will strengthen over east-central Colorado, this will feed moisture into our CWA as flow becomes southerly to southeasterly. This coupled with an upper- level shortwave that slides across the region as the ridge that has been dominating our weather slides off to the east. These two features will be the catalyst in driving today's weather. With the influx of moisture, clouds are likely to develop during the morning hours which could hamper the destabilization of the atmosphere, possibly delaying the thunderstorm development. However, guidance tells a different story and that this cloud cover will not delay thunderstorm activity. As the sun burns off the clouds, highs will soar into the 80s, helping to increase the instability. As such, hi- res guidance is picking up on the initialization nicely at around 1PM along I-25. Then, over the next few hours, making it into the Nebraska Panhandle by 3PM. Lets briefly take a look at what else in the atmosphere that is creating a prime environment for this to happen this afternoon. A few other severe indices that we look at concur with a severe threat this afternoon, with Convective Available Potential Energy (CAPE) values upwards of 2000 J/KG and bulk shear values of 50-70 knots will support rotating and strong updrafts, combined with a few other favorable parameters, severe thunderstorms that may produce tornadoes and very large hail are likely this afternoon across eastern Wyoming and the Nebraska Panhandle. Frankly, the concerning aspect of this convection is that the hi-res guidance is developing discrete long-tracked supercells, capable of producing 2"+ hail, strong winds, and long-track tornadoes. Therefore, the Storm Prediction Center (SPC) has much of far eastern Wyoming and the Nebraska Panhandle under a slight risk (2 of 5) for severe weather and a marginal risk (1 of 5) for the remainder of the CWA east of I-25. The other thing that can't be over looked, are the chances of flash flooding in any of these storms. The atmosphere will be moist and with precipitable water values of an inch or more over the area of concern, flash flooding will be a very serious threat this afternoon as well. Turn around, don't drown. By the late evening hours, most of the activity should be out of our region, though some lingering showers and sub-severe thunderstorms will likely persist.

LONG TERM /SUNDAY THROUGH FRIDAY/

Issued at 232 PM MDT Fri Jun 19 2026

It will be a semi-active pattern for the long term. Sunday, a shortwave will drop down into the Intermountain West to continue our chances for much needed rain for our farmers. Some lingering mid-level moisture from Saturday will look to be sufficient for afternoon showers and thunderstorms. SPC has a Slight risk for Cheyenne County in Nebraska and a Marginal Risk from Kimball to Alliance. The rest of forecast area is in a general thunder instead of a severe risk. Monday into Tuesday, A low pressure system drops into a the Northern Plains sending a frontal passage through our area. This weak front will bring some cool air over the Intermountain West keeping our temperatures mostly in the 70's for both days but some isolated 80 temperatures will be possible as warm dry air starts to also push in from the West. As more of the dry air begins to filter in over night RH values West of I-25 will start to drop into the teens while everything east will stay into the 30's and 40's. This dry air will most likely follow the upper level ridge that sets up on the West coast and slightly pushes east. The ridge does look to compress on the back half of the work week to allow some low chances for rainfall as more shortwaves push into Pacific Northwest from the Alaskan Bay.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 525 AM MDT Sat Jun 20 2026

Low CIGs, dropping flight categories down to IFR and/or LIFR, have moved in and are impacting KCYS, KBFF, KSNY, and KAIA. Low CIGs will eventually erode a bit later this morning, then aviation concerns turn to afternoon showers and thunderstorms across the CWA. There is increasing confidence in strong to severe storms across far eastern Wyoming and western Nebraska this afternoon and I tried to reflect this in the TAFs. There remains the potential that storms will linger into the evening hours.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...None.