252
FXUS65 KCYS 070843
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
243 AM MDT THU AUG 7 2025
KEY MESSAGES
- LARGELY HOT AND DRY CONDITIONS ARE EXPECTED ACROSS THE AREA
THROUGH FRIDAY. AREAS OF SMOKE FROM WILDFIRES TO OUR SOUTHWEST
ARE EXPECTED TO PRODUCE PERIODS OF DEGRADED AIR QUALITY.
- AN ISOLATED STRONG TO SEVERE THUNDERSTORM CANNOT BE RULED OUT
THIS AFTERNOON/EVENING, MAINLY IN THE NORTHERN NE PANHANDLE
AND EAST CENTRAL WY.
- RED FLAG WARNINGS REMAIN IN EFFECT THROUGH FRIDAY DUE TO LOW
AFTERNOON RELATIVE HUMIDITY AND POOR OVERNIGHT HUMIDITY
RECOVERIES.
SHORT TERM /THROUGH FRIDAY NIGHT/
ISSUED AT 243 AM MDT THU AUG 7 2025
TODAY, THE RIDGE WILL PEAK OVERHEAD AS A LOW PRESSURE SYSTEM MOVES
INTO THE PACIFIC NORTHWEST. THIS SYSTEM AMPLIFIES THE RIDGE OVER US
INCREASING THE DRY AIR ADVECTION FROM THE DESERT SOUTHWEST. THE
PRESSURE GRADIENT WILL ALSO INCREASE EXPANDING FIRE WEATHER CONCERNS
FOR THE SOUTHEAST WYOMING AREA. AS GUSTY WINDS LOOK TO BE OCCURRING
A FIRE WEATHER WATCH WAS PUT OUT FOR THE NEBRASKA PANHANDLE. IN
ADDITION TO MARGINAL GUSTY WINDS THE DRYLINE IS EXPECTED TO PUSH
EAST FOLLOWING THE APEX OF THE RIDGE. RH VALUES ARE EXPECTED DROP
BELOW 15 PERCENT IN THE PANHANDLE. TODAY IS ALSO EXPECTED TO BE THE
WARMEST DAY OF THE WEEK AS 700MB TEMPERATURES ARE EXPECTED RANGE
BETWEEN 18 AND 21 DEGREES. THIS TRANSLATES TO SURFACE TEMPERATURES
REACHING INTO THE 90'S AND POSSIBLY LOW HUNDREDS FOR THE NEBRASKA
PANHANDLE.
FRIDAY, THE FRONT SIDE OF AN UPPER LEVEL LOW WILL BEGIN TO SUPPRESS
THE UPPER LEVEL RIDGE COOLING US OFF A LITTLE BIT. HOWEVER, THE
MOISTURE WON'T ARRIVE UNTIL THE EVENING SO WE WILL REMAIN A LITTLE
DRY DURING THE DAY. RH VALUES WILL FLOAT BETWEEN 15 AND 20 PERCENT.
THE FAR EASTERN PORTION OF THE PANHANDLE MAY SEE RH VALUES AS HIGH
AS 30 PERCENT DURING THE DAY. TEMPERATURES WILL REMAIN IN THE 80'S
AND 90'S HOWEVER IT WILL STILL BE COOLER THAN THURSDAY. AS THIS
UPPER LEVEL LOW PUSHES INTO THE INTERMOUNTAIN WEST A SMALL SHORTWAVE
MAY BE STRONG ENOUGH TO LIFT WHAT LITTLE MOISTURE WE HAVE TO CREATE
THUNDERSTORMS IN THE LATE AFTERNOON AND EVENING. CAPE VALUES ARE
EXPECTED TO BE BETWEEN 1000 AND 2000 JOULES WITH MID-LEVEL LAPSE
RATES BETWEEN 8 AND 9C/KM. IF THE STORMS ARE ABLE TO TAP INTO THIS
ENERGY THERE COULD BE A FEW STRONG TO SEVERE THUNDERSTORMS. HOWEVER,
THE EFFECTIVE SHEAR MAY BE INSUFFICIENT TO SUSTAIN THEM FOR LONG AS
THESE STORMS ARE LIKELY TO BE PULSY IN NATURE.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
ISSUED AT 400 PM MDT WED AUG 6 2025
THE LONG TERM PERIOD CONTINUES TO ADVERTISE A MORE ACTIVE SYNOPTIC
PATTERN ACROSS THE REGION THROUGH THE WEEKEND. THE MID-/UPPER-LEVELS
WILL BE CHARACTERIZED BY LONGWAVE TROUGHING WITH EMBEDDED
SHORTWAVES/DISTURBANCES. MOISTURE ASSOCIATED WITH THESE DISTURBANCES
PROMOTE SLIGHT CHANCE TO CHANCE POPS (~15% TO ~45%) SATURDAY
AFTERNOON THROUGH SUNDAY AFTERNOON, MAINLY EAST OF THE LARAMIE
RANGE. ON THAT NOTE, WESTERN PORTIONS OF THE COUNTY WARNING AREA
(CWA) MAY NOT SEE ANY RAIN, AS PRECIPITATION WILL HAVE TO OVERCOME
DRIER MID-/LOWER-LEVEL AIR TO REACH THE GROUND. WIND SPEED
MAXIMA/WIND SHEAR ASSOCIATED WITH THESE DISTURBANCES ALOFT MAY
ORGANIZE AND/OR INTENSIFY CONVECTION, BUT AT THIS TIME, THE
PROBABILITY FOR WIDESPREAD SEVERE WEATHER REMAINS LOW. SUBTLE
DIFFERENCES IN THE TIMING/EVOLUTION OF THE DISTURBANCES REMAIN AMONG
THE GLOBAL MODELS, BUT THERE IS GENERAL AGREEMENT REGARDING THE
OVERALL SYNOPTIC PATTERN. TEMPERATURES WILL TREND DOWN SLIGHTLY OVER
THE WEEKEND -- FORECAST HIGHS ARE GENERALLY IN THE MID-70S TO MID-
80S AND FORECAST LOWS ARE GENERALLY IN THE UPPER 40S TO UPPER 50S.
THE GFS AND ECMWF PROG THE MID-/UPPER-LEVEL TROUGH AXIS TO SHIFT
EAST OF THE CWA ON SUNDAY NIGHT/MONDAY MORNING, WITH NORTHWESTERLY
FLOW ALOFT SETTING UP FOR MONDAY AND TUESDAY. AS A RESULT, OVERALL
DRIER CONDITIONS ARE EXPECTED AT THE START OF NEXT WEEK (POPS ARE
LESS THAN ~25% AND RELEGATED TO THE EASTERN AND SOUTHERN PORTIONS OF
THE CWA) AND AFTERNOON TEMPERATURES SHOULD RETURN TO THE MID-80S TO
UPPER 80S.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1011 PM MDT WED AUG 6 2025
WEST SOUTHWEST FLOW ALOFT WILL CONTINUE. SKIES WILL BE MOSTLY
CLEAR, WITH SCATTERED CLOUDS NEAR 12000 FEET FROM 15Z TO 01Z.
WINDS WILL GUST TO 30 KNOTS AT THE WYOMING TERMINALS FROM 15Z TO
01Z, AND WILL REMAIN 11 KNOTS OR LESS AT THE NEBRASKA TERMINALS.
CYS WATCHES/WARNINGS/ADVISORIES
WY...RED FLAG WARNING FROM NOON TODAY TO 8 PM MDT THIS EVENING FOR
WYZ417-418.
RED FLAG WARNING UNTIL 6 PM MDT FRIDAY FOR WYZ419>429.
AIR QUALITY ALERT UNTIL NOON MDT TODAY FOR WYZ105-109>119.
NE...FIRE WEATHER WATCH FROM NOON MDT TODAY THROUGH THIS EVENING
FOR NEZ434>437.
SHORT TERM...MM
LONG TERM...WFOCYS
AVIATION...RUBIN
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