415
FXUS65 KCYS 070002 AAA
AFDCYS
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
602 PM MDT WED AUG 6 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 400 PM MDT WED AUG 6 2025
THE POWERFUL RIDGE OVER ARIZONA AND NEW MEXICO CONTINUES TO
STRENGTHEN TODAY, WITH THE LATEST RAP ANALYSIS SHOWING 500-MB
HEIGHTS EXCEEDING 600-DM. LIMITED RECYCLED MONSOON MOISTURE
CONTINUES TO CIRCULATE TIGHTLY AROUND THE RIDGE CENTER, BUT A NARROW
BAND OF VERY DRY AIR REMAINS STUCK OVER SOUTHERN WYOMING AND WESTERN
NEBRASKA. ALONG AND WEST OF THE LARAMIE RANGE, THE ATMOSPHERE IS
VERY WELL-MIXED, SUPPORTING EXTREMELY DRY SURFACE CONDITIONS.
FURTHER EAST, A SURFACE HIGH WELL TO OUR EAST NUDGED AGAINST THE I-
25 CORRIDOR THIS MORNING, AND REMAINS FAIRLY STUBBORN HEADING INTO
THE AFTERNOON. EAST WINDS AND HIGHER SURFACE MOISTURE REMAIN
CONSIDERABLY WEST OF EARLIER MODEL FORECASTS, LEADING TO
TEMPERATURES RUNNING COOLER AND DEWPOINTS RUNNING HIGHER THAN
PREVIOUS FORECASTS. MESOANALYSIS INDICATES PLENTIFUL INSTABILITY AND
VERTICAL WIND SHEAR IN PLACE OVER THE HIGH PLAINS, BUT A VERY STRONG
CAP IS THE PRIMARY INHIBITOR FOR CONVECTIVE ACTIVITY. THE RESULT OF
THIS IS LOW CONFIDENCE IN ANY STORMS DEVELOPING AT ALL, BUT IF
STORMS DO MANAGE TO DEVELOP, THEY WILL BE ABLE TO TAP INTO A POTENT
ENVIRONMENT AND BECOME STRONG TO SEVERE. STORM COVERAGE WILL NOT BE
VERY HIGH, BUT ISOLATED STORMS WILL BE CAPABLE OF DEVELOPING INTO
SUPERCELLS WITH LARGE HAIL AND DAMAGING WINDS POSSIBLE.
MEANWHILE, SATELLITE OBSERVATIONS SHOW THE LEE AND ELK FIRES NEAR
MEEKER, COLORADO BECOMING ACTIVE ONCE AGAIN THIS AFTERNOON, PUTTING
OUT A GROWING SMOKE PLUME TO THE EAST-NORTHEAST. EXPECT TO SEE
INCREASING HAZE IN THE LARAMIE AND CHEYENNE AREAS AS THIS PLUME
MOVES INTO THE AREA. OVERNIGHT, EXPECT DRAINAGE FLOW TO INCREASE
SURFACE SMOKE CONCENTRATIONS ACROSS SOUTHERN WYOMING. AS A RESULT,
AN AIR QUALITY ALERT HAS BEEN ISSUED FOR MUCH OF CARBON, ALBANY, AND
LARAMIE COUNTIES IN COORDINATION WITH THE WYOMING DEQ. THURSDAY WILL
BE THE HOTTEST DAY OF THE WEEK AS 700-MB TEMPERATURES CREST AROUND
+17 TO +19C. THE SURFACE TROUGH AND ASSOCIATED DRYLINE IS EXPECTED
TO ADVANCE WELL INTO THE NEBRASKA PANHANDLE, ALLOWING WESTERLY
DOWNSLOPE WINDS TO SPREAD EASTWARD ACROSS THE HIGH PLAINS AND BOOST
THE LOW-LEVEL WARMTH. FORECAST HIGHS ARE GENERALLY WITHIN 1 TO 3F OF
DAILY RECORD HIGHS, ALTHOUGH NO RECORD IS EXPLICITLY FORECAST AT
THIS TIME. WHILE THE BOUNDARY LAYER WILL BE QUITE DRY FOR THE ENTIRE
AREA, WE MAY SEE A FEW ISOLATED HIGH BASED SHOWERS AND THUNDERSTORMS
DEVELOP IN THE AFTERNOON HOURS, MAINLY IN THE CENTRAL AND NORTHERN
NEBRASKA PANHANDLE. LOW-END POPS CONTINUE FOR THIS AREA.
BY FRIDAY, AN UPPER LEVEL SHORTWAVE WILL BEGIN TO ENCROACH ON THE
AREA AND SUPPRESS THE POWERFUL RIDGE TO THE SOUTH. COOLER AND MORE
MOIST AIR WILL WORK INTO THE HIGH PLAINS (MOSTLY ALONG/NORTH OF THE
NORTH PLATTE RIVER VALLEY) DURING THE MORNING HOURS WHILE POINTS
AROUND CHEYENNE AND WESTWARD WILL REMAIN QUITE DRY. THE INCREASED
MOISTURE AND EXPECTED STRONG VERTICAL WIND SHEAR WILL POSSIBLY ALLOW
FOR A FEW ISOLATED STRONG TO SEVERE THUNDERSTORMS. THIS WILL ALSO
BRING A LITTLE RELIEF FROM THE HEAT WITH HIGHS ALONG THE US-20 10-
15F COOLER THAN THURSDAY, WHILE THOSE FURTHER SOUTH WILL BE SLIGHTLY
COOLER, BUT ONLY BY PERHAPS 3-5F.
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 /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 540 PM MDT WED AUG 6 2025
MAIN FORECAST CHALLENGE FOR THE TAF PERIOD WILL BE POTENTIAL
FOR LOW CEILINGS/REDUCED VISIBILITY AT THE NEBRASKA TERMINALS
OVERNIGHT/EARLY TOMORROW (THURSDAY) MORNING. FOR THIS TAF CYCLE,
HAVE GONE WITH SCT MVFR CLOUDS AT ALL FOUR OF THESE SITES FROM
09Z/10Z TO 14Z, WITH FEW005 AND BR AT SNY AND AIA GIVEN CIG/VIS
REDUCTIONS AT BOTH SITES THIS MORNING. VFR CONDITIONS ARE
EXPECTED AT THE WYOMING TERMINALS THROUGH THE PERIOD, AS WELL AS
GUSTY CONDITIONS TOMORROW -- WINDS ARE FORECAST TO BE 13-20 KTS
WITH GUSTS 20-30 KTS.
CYS WATCHES/WARNINGS/ADVISORIES
WY...RED FLAG WARNING FROM NOON TO 8 PM MDT THURSDAY FOR WYZ417-418.
RED FLAG WARNING UNTIL 6 PM MDT FRIDAY FOR WYZ419>429.
AIR QUALITY ALERT FROM MIDNIGHT TONIGHT TO NOON MDT THURSDAY
FOR WYZ105-109>119.
NE...NONE.
SHORT TERM...MN
LONG TERM...KM
AVIATION...KM
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