FXUS65 KCYS 262302

AFDCYS



Area Forecast Discussion

National Weather Service Cheyenne WY

502 PM MDT Thu Jun 26 2025



.KEY MESSAGES...



- Fire weather conditions are probable for Western portion of

  the forecast area tomorrow. 



- Warm temperatures and daily coverage of scattered afternoon

  and evening showers and thunderstorms expected for the weekend

  through Thursday.



&&



.SHORT TERM /THROUGH FRIDAY/...

Issued at 235 PM MDT Thu Jun 26 2025



Looking at Water Vapor imagery, there's a lot of dry air at the 

lower levels that keeps us from getting some scattered showers as a 

small shortwave pushes through the intermountain west later this 

afternoon/evening. There may be quick isolated showers as some 

moisture floats in from the midlevels as seen on water vapor, but 

it's uncertain if it will be enough to spark anything. Most of the 

more abundant water vapor is still shown to be in the Pacific 

Northwest. As the shortwave moves through there may be around a 

couple hundred joules of CAPE still left but doesn't look like it 

may be enough to produce anything strong or severe. A few bolts of 

lightning may still be generated along with some thunder and light 

rain. Models depict most of these showers will be contained in the 

mountains if they were to develop. Friday, Looks to be almost the 

same scenario as a weak shortwave looks to push through the 

Intermountain West. Friday, will also be a little bit warmer with 

temperatures in the 80's east of I-25 and in the 70's possibly 80's 

in the mountains. There is a little more CAPE especially in the 

Panhandle with progged values around 1000-1500 j/kg. However, most 

models have the storms developing mostly in the Panhandle where the 

moisture is a little better with the higher CAPE values. SPC did 

issue a Marginal risk for the southern panhandle as most of the 

convection seems to develop late, strengthen quickly but also move 

out of our CWA quickly as well. There are some embedded vort-maxes 

that will move with the shortwave but it's uncertain if the timing 

of the forcing will line up with our diurnal heating and moisture. 

The winds will be a little gusty and the RH values are forecasted to 

be below 15 percent so a fire weather watch was also issued for 

Carbon county Friday as well since their fuels were reported to be 

turned over already due to the lack of rain in that county.



&&



.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...

Issued at 235 PM MDT Thu Jun 26 2025



Saturday...Zonal flow aloft continues. Another warm day expected 

with 700 mb temperatures near 15 Celsius, yielding high temperatures 

from the mid 80s to mid 90s. With a shortwave trough overhead, and 

low level convergence noted near the Wyoming and Nebraska state 

line, we anticipate isolated to scattered afternoon and evening 

showers and thunderstorms along and east of I-25.



Sunday...Somewhat cooler temperatures in the wake of a cold front 

and with an increase in cloud cover. Looks like adequate low and mid 

level moisture for scattered late day showers and thunderstorms, 

mainly east of I-25.



Monday...Temperatures about the same as on Sunday, with low level 

upslope east winds and 700 mb temperatures near 11 Celsius. Despite 

adequate low and mid level moisture, we may see a decrease in 

coverage of showers and thunderstorms due to ridging aloft.



Tuesday...A warming trend develops as 700 mb temperatures rise to 

near 13 Celsius. Adequate moisture aloft for isolated to scattered 

late day showers and thunderstorms, mainly east of I-25.



Wednesday...The warming trend continues as 700 mb temperatures reach 

14 Celsius. Moisture looks a bit more prevalent than Tuesday, thus 

we should see an increase in convective coverage, including west of 

I-25.



Thursday...Similar temperatures to Wednesday with 700 mb 

temperatures near 14 Celsius.Adequate low and mid level moisture 

again, thus scattered late day showers and thunderstorms

expected.&&



.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...

Issued at 1127 AM MDT Thu Jun 26 2025



VFR conditions expected over the next 24 hours. FEW to SCT

clouds at mid levels expected this afternoon, and should begin

clearing overnight. Some precipitation may form off of the high

terrain this afternoon and most eastwards, most likely impacting

KLAR and KCYS. Some of these showers could make their way over

to the Nebraska Panhandle, but probabilities are too low to

include in TAFs at this time. Any showers or possible

thunderstorms that do impact sites could briefly lower

visibilities and CIGs.



&&



.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...

Issued at 459 PM MDT Thu Jun 26 2025



Fairly quiet this evening into the overnight hours tonight. Some

isolated showers may drift around the KLAR and KCYS tonight, 

but confidence is fairly low. Skies clear out overnight tonight,

introducing a slight chance for fog at KBFF and KCDR. Confidence

is low at this time, but will continue to refine the fog

forecast in the next TAF periods.



&&



.CYS WATCHES/WARNINGS/ADVISORIES...

WY...Fire Weather Watch Friday afternoon for WYZ421>423-425-427.

NE...None.



&&



$$



SHORT TERM...MM

LONG TERM...RUBIN

AVIATION...AM

