textproduct: Cheyenne

KEY MESSAGES

- Widespread showers and storms are expected over the next several days. Monsoon moisture will lead to heavy rain with the potential for flash flooding. Isolated severe storms will also be possible.

- A drier and warmer airmass will spread across the region for Friday, with even hotter conditions for Saturday through Monday and possible Heat Advisories over the weekend and on Monday. Some cooling is anticipated for Tuesday and Wednesday.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 133 PM MDT Wed Jul 22 2026

Today, The core of central high pressure remains over the Oklahoma panhandle and NW Texas area. The synoptic forcing is a little bit stronger today with stronger vorticity lobes and Warm air advection as well as pockets of MUCAPE ranging between 1000-1500 joules. Looking at this mornings model runs NAEFS increased the IVT signal and placed a maxed value over Goshen county while the rest of the forecast area is blanketed in 90 to 99.7th percentile values indicating a stronger moisture transport from the tropical Pacific (Baja California) into the Intermountain West. Storm Coverage was also slightly upgraded from a numerous scheme to a more widespread/ training thunderstorm pattern this afternoon and evening. With the increased moisture advection and training storm signal a Flood watch was issued for the Forecast area with two different start times corresponding to when storms are expected and method of flooding. The flood watch went into effect at noon today and will expire at midnight Thursday for Southeast Wyoming. The main threat for the higher terrain will be mostly excessive runoff collecting and flooding low lying areas in the valleys. Our streams and river may also run a little bit higher as the runoff increases in the evening but with the lack of rain leading to lower stream and river levels, The runoff is expected to be contained in the banks of the rivers and streams. For areas east of I-25 and the Nebraska Panhandle, the most likely flooding threat remains the same. Our Dry soils with develop this initial Hydrophobic effect when the rain hits the ground leading to increased runoff before soaking into the soil. Training thunderstorms with torrential rainfall will increase this effect possibly flooding irrigation canals and flow over low lying roadways and farmland. In urban areas some roadways may be come flooded as the drainage systems may temporarily overwhelmed but eventually the water is expected to clear itself out. WPC has issued a Slight risk for the higher terrain in Southeast Wyoming and a Marginal risk for areas East of I-25 for excessive rainfall. SPC also drew a Marginal Risk for Severe thunderstorms today for Eastern Laramie County and majority of the Southern Panhandle for wind gusts between 60 to 65 mph. These wind gusts are expected to be isolated and caused from collapsing updrafts from dying or cycling thunderstorms creating a brief but strong microburst type wind gusts. Thunderstorms are expected to linger overnight as they gradually push east. The flood watch ends Midnight Thursday as storms with torrential rainfall are expected once more but the good news is the coverage may not be as widespread so there is a chance the flood watch may be cancelled a little early but we shall see on that. MUCAPE is about the same as today with pockets of 2,000 to possibly 3,000 joules collocated with the saturated layer but the upper level ridge still puts a damper on shear so robust severe storms aren't expected tomorrow as well. Tomorrow also has a little bit more isentropic ascent so its not really out of the realm of possibility to have another afternoon of heavy rainmakers in the lower elevations. Temperatures are expected to be in the 80's with some areas possibly reaching 90 to 93 this afternoon but as cloud cover starts to increase, temperatures should drop into the 70's and 80's tomorrow afternoon. However, the cloud cover will act as a thin blanket overnight leaving the intermountain west as little warmer with temperatures in the 60's for overnight lows.

LONG TERM /FRIDAY THROUGH WEDNESDAY/

Issued at 133 PM MDT Wed Jul 22 2026

Friday...Will see an abrupt cutoff to the low and mid level moisture supply as drier air at low and mid levels advects into our counties as the dominant ridge over Colorado and southern Wyoming reasserts itself. Thus dry and hotter.

Saturday through Wednesday...Isolated to scattered afternoon and evening showers and thunderstorms expected, with areal coverage increasing each day due to increased mid level moisture. Fortunately, more beneficial rains expected concentrated over and near our Snowy, Sierra Madre and Southern Laramie Ranges, with the best chances for convection on Monday through Wednesday. Typical weak northwest flow aloft on the northeast periphery of the ridge aloft will aid in occasional passing shortwave troughs aloft near peak heating resulting in increasing convective potential each day.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1133 PM MDT Wed Jul 22 2026

Regional radars are showing widespread shower and limited storm activity. Currently it is raining at KRWL and KSNY, with showers moving out of KAIA and into KCDR. This on and off showers are expected through sun rise. Some areas of fog may develop at terminals, however model guidance are not certain enough to include in the 06z TAFs. Amendments may be required should terminals experience fog. Lower ceilings are the most likely outcome, some of which would impose MVFR conditions. Winds generally calm and turning west to northwest while the shortwave trough moves through tomorrow morning through afternoon.

Another few round of storms and showers will develop after around 18z. Reduced visibilities from heavy rain, low CIGs, and lightning are possible from this activity.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Flood Watch through Thursday evening for WYZ101>111-113- 115>119. NE...Flood Watch through Thursday evening for NEZ002-003-019>021- 054-055-095-096.