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FXUS65 KCYS 031940
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
ISSUED BY NATIONAL WEATHER SERVICE RIVERTON WY
140 PM MDT THU SEP 3 2026
KEY MESSAGES
- RED FLAG WARNING IN EFFECT FOR CONVERSE AND NIOBRARA
COUNTIES.
- WARMING AND DRYING TREND EXPECTED THROUGH THE END OF THE WEEK.
- PRECIPITATION CHANCES RETURN FOR THE BEGINNING OF NEXT WEEK.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 139 PM MDT THU SEP 3 2026
TONIGHT…DRY SOUTHWEST FLOW ALOFT PREVAILS WITH A QUIET NIGHT ON TAP AND
COOL OVERNIGHT MINIMAL TO PRODUCE GOOD SLEEPING CONDITIONS FOR
OPENING UP WINDOWS.
FRIDAY…THE MAIN WEATHER STORY WILL BE THE HEAT, WITH SOUTHWEST WINDS
ALOFT AND SURFACE LOW PRESSURE AND A THERMAL RIDGE AXIS OVER OUR
COUNTIES. WITH 700 MB TEMPERATURES NEAR 15 CELSIUS AND DOWNSLOPE
WINDS AND LITTLE IF ANY CLOUD COVER, MAXIMUM TEMPERATURES WILL
SOAR INTO THE MID 80S TO NEAR 90 DEGREES WEST OF I-25, WITH
BLISTERING HEAT FURTHER EAST OF I-25, WITH MAXIMUM TEMPERATURES
IN THE 90S, TO NEAR 100 DEGREES OVER THE NEBRASKA PANHANDLE.
RECORD HIGH TEMPERATURES, YEAR AND FORECAST HIGH TEMPERATURES FOR
SEPTEMBER 4…
RAWLINS 95/1998…83
LARAMIE 89/2022…84
CHEYENNE 94/2022…90
CHADRON 104/1978…101
ALLIANCE 101/1998…96
SCOTTSBLUFF 102/1998…99
SIDNEY…100/1998…99
FRIDAY NIGHT…A WEAK SHORTWAVE TROUGH ALOFT MOVES TO OUR SOUTHERN
COUNTIES BY DAWN, SPAWNING ISOLATED TO SCATTERED SHOWERS NEAR
A CHEYENNE TO TORRINGTON LINE, OTHERWISE DRY AND COOL.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
ISSUED AT 201 PM MDT WED SEP 2 2026
SATURDAY...SOUTHWEST FLOW ALOFT PREVAILS. LOOKS LIKE WITH A
MINOR STREAM OF THE MONSOONAL MOISTURE TAP, WE ANTICIPATE
ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS IN THE
AFTERNOON AND EVENING.
SUNDAY...THE PRECIPITABLE WATER VALUES INCREASE SOMEWHAT AS
MONSOONAL MOISTURE INCREASES. WITH THAT SAID, EXPECT SCATTERED
AFTERNOON SHOWERS AND THUNDERSTORMS TO FORM OVER AND NEAR OUR
SNOWY RANGE AND LARAMIE RANGE IN THE AFTERNOON DUE TO OROGRAPHIC
EFFECTS AND DIFFERENTIAL HEATING, WITH MOST OF THE CONVECTION
PROPAGATING OVER THE NEBRASKA PANHANDLE IN THE EVENING.
MONDAY...SOMEWHAT DRIER AIR ALOFT MOVES OVERHEAD UNDER
SOUTHWEST FLOW ALOFT, WHICH SHOULD CORRESPOND TO AN AREAL
DECREASE IN AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.
TUESDAY AND WEDNESDAY...AGAIN, SOMEWHAT DRIER AIR INFILTRATES
OUR WESTERN COUNTIES USING PRECIPITABLE WATER VALUES, WITH A BIT
BETTER MOISTURE FURTHER EAST, THUS ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS EXPECTED MAINLY OVER THE MOUNTAINS AND
EASTWARD.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1142 AM MDT THU SEP 3 2026
VFR CONDITIONS EXPECTED THROUGHOUT THE FORECAST PERIOD. A FEW TO SCATTERED
CUMULUS AND CIRRUS CLOUDS THIS AFTERNOON. WINDS OUT OF THE WEST TO
SOUTHWEST FOR MOST TERMINALS UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE.
WINDS RELAX TONIGHT TO BECOME VARIABLE AFTER 01/02Z. A WEAK SHORTWAVE TROUGH
WILL PASS THROUGH FRIDAY MORNING TO CREATE SOME CLOUD COVERAGE. MOST OF
THIS COVERAGE PASSES BY AROUND THE END OF THE FORECAST PERIOD.
CYS WATCHES/WARNINGS/ADVISORIES
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ417-418.
NE...NONE.
SHORT TERM...WFOCYS
LONG TERM...WFOCYS
AVIATION...WFOCYS
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