047
FXUS65 KCYS 092326
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
526 PM MDT FRI OCT 9 2026
KEY MESSAGES
- ABOVE AVERAGE TEMPERATURES WITH DRY AND BREEZY CONDITIONS
LEAD TO A FIRE WEATHER WATCH IN THE NEBRASKA PANHANDLE ON
SATURDAY.
- A PATTERN CHANGE WILL BRING A GRADUAL COOL DOWN AND INCREASED
CHANCES FOR PRECIPITATION SUNDAY THROUGH MUCH OF NEXT WEEK.
SHORT TERM /THROUGH SUNDAY/
ISSUED AT 306 PM MDT FRI OCT 9 2026
THE SHORT TERM FORECAST WHEN MAKING HEADLINE DECISIONS HAS A LOT OF
UNCERTAINTY BECAUSE OUR FORECAST AREA IS ON THE BORDER OF SOME
CRITICAL WEATHER ELEMENTS. AT THE UPPER LEVELS THERE ARE TWO DYNAMIC
LOW PRESSURE SYSTEMS PUSHING INTO THE WESTERN COASTAL REGION. ONE IS
HITTING US FROM THE PACIFIC NORTHWEST AND THE OTHER IS HURRICANE
RACHEL. THESE LOW PRESSURE SYSTEMS WILL COLLIDE AGAINST OUR WEAK
UPPER LEVEL RIDGE. THIS RIDGE WILL SLOWLY PUSH EAST CREATING A SORT
OF DIVISION BETWEEN OUR SOUTHEAST WY AND NEBRASKA PANHANDLE FORECAST
AREA SECTIONS. THESE SYSTEMS WILL BE FUNNELING PACIFIC MOISTURE INTO
THE ROCKY MOUNTAINS WHILE TIGHTENING THE PRESSURE GRADIENT ALLOWING
FOR GUSTY WINDS TODAY AND TOMORROW. THE MOUNTAINS ON THE WESTERN
SIDE OF WYOMING WILL ABSORB MOST OF THE MOISTURE FLOW BUT THERE
LOOKS TO BE ENOUGH TO PRODUCE SOME SHOWERS FOR OUR AREA WEST OF I-
25. FOR AREAS EAST OF I-25 IN SOUTHEAST WYOMING IT LOOKS TO BE MORE
MICROBURST-VIRGA REGIME. THE DRY AIRMASS UNDERNEATH THE RIDGE WILL
STILL RESIDE OVER THE PANHANDLE AND POSSIBLY TORRINGTON FOR LOWER RH
VALUES AND LIGHTER WINDS. GUSTY WINDS OF AT LEAST 35-40 MPH LOOK TO
BE LIKELY ACROSS SOUTHEAST WYOMING WHILE THE PANHANDLE WILL BE A
LITTLE BIT LESS WITH MAX WIND GUSTS UP TO 25 MPH. THEREFORE, A FIRE
WEATHER WATCH WAS ISSUED FOR THE NEBRASKA PANHANDLE AND A PORTION OF
GOSHEN COUNTY. THERE IS SOME UNCERTAINTY IF THE WIND GUSTS WILL LAST
THE 3 HOUR TIME REQUIREMENT FOR A RED FLAG WARNING SO THAT WHY THE
WATCH WAS ISSUED INSTEAD. SATURDAY NIGHT THE STRONGER WINDS WILL
REACH PORTIONS OF THE NEBRASKA PANHANDLE BUT BY THE TIME THEY DO OUR
RH RECOVERY WILL BE WAY ABOVE ANY FIRE WEATHER THRESHOLD. SO ITS A
LITTLE BIT OF A TRICKY FORECAST FOR OUR AREA SINCE WE ARE RIGHT ON
THE LINE FOR SOME THINGS. TEMPERATURES WILL ALSO DECREASE AS THE
MOISTURE AND SHOWERS MOVES ACROSS SOUTHEAST WYOMING RANGING BETWEEN
70 AND 80 DEGREES WHILE THE PANHANDLE WILL BE FAIRLY WARM WITH
TEMPERATURES BETWEEN 80 AND 90 DEGREES.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
ISSUED AT 435 PM MDT FRI OCT 9 2026
THE STAGNANT WARM AND DRY WEATHER PATTERN WILL FINALLY BREAK ON
SUNDAY AS A POWERFUL UPPER LEVEL LOW APPROACHES THE AREA FROM THE
WEST. A COMPLEX INTERACTION WILL TAKE PLACE BETWEEN THE APPROACHING
TROUGH, WHICH WILL BE IN THE PROCESS OF SPLITTING, AND THE REMNANT
MOISTURE/CIRCULATION OF FORMER HURRICANE RACHEL. THE BEST SYNOPTIC
FORCING FOR CONSISTENT RAINFALL WILL STALL TO OUR WEST, WHICH HAS
RESULTED IN A DRIER TREND FOR MUCH OF OUR AREA IN THE LAST FEW
FORECAST CYCLES. THAT BEING SAID, WE WILL STILL HAVE ABUNDANT
MOISTURE IN PLACE OVER THE AREA. ENSEMBLE MEAN PRECIPITABLE WATER IS
AROUND 3 TO 4 STANDARD DEVIATIONS ABOVE THE MEAN, NEAR
CLIMATOLOGICAL MAXIMUMS. STILL, WITH WEAK FORCING AND UNIMPRESSIVE
INSTABILITY, PRECIPITATION EXPECTATIONS ARE ON THE LOW SIDE. RAWLINS
AND DOUGLAS, WHICH WILL BE CLOSEST TO THE STRONGEST FORCING, HAVE
ENSEMBLE MEDIAN QPF VALUES ONLY AROUND 0.1 TO 0.2" FOR THE FIRST
PHASE OF THIS EVENT WHICH WILL LAST THROUGH MONDAY MORNING. FURTHER
EAST, EXPECT A FEW SHOWERS SUNDAY INTO SUNDAY NIGHT, BUT
PRECIPITATION SHOULD BE FAIRLY LIMITED. IN ADDITION TO THE SHOWERS,
GUSTY SOUTHWEST WINDS WILL CONTINUE ALONG AND WEST OF THE LARAMIE
RANGE. PROBABILITIES FOR HIGH WINDS PEAK AROUND 30% IN THE WIND
PRONE AREAS ON MONDAY MORNING, BUT EXPECT FAIRLY CONSISTENT GUSTY
WINDS ALL THE WAY THROUGH AT LEAST MONDAY.
MEANWHILE, THE NORTHERN BRANCH OF THE SPLIT TROUGH WILL DROP A
SURFACE HIGH PRESSURE DOWN FROM THE NORTH. THE SURFACE FRONT WILL
PUSH INTO THE AREA SUNDAY, BUT STALL AROUND THE LARAMIE RANGE. AS A
RESULT, WE CAN EXPECT A SIGNIFICANT COOL DOWN FOR OUR NORTHERN
AREAS, SOLIDLY BEHIND THE FRONT, WITH SUNDAY'S HIGHS AROUND 15
DEGREES COOLER THAN SATURDAY. THE FRONT WILL STRUGGLE TO REACH THE I-
80 CORRIDOR, SO 24-HOUR TEMPERATURE DROPS IN THIS AREA WILL BE ONLY
AROUND 5 DEGREES OR SO WITH HIGHS REMAINING WELL ABOVE AVERAGE. THE
UPPER LEVEL LOW DIGGING INTO THE WEST COAST WILL HELP AMPLIFY THE
DOWNSTREAM RIDGE OVER THE CENTRAL CONUS ON MONDAY, HELPING TO PUSH
DRIER AIR A LITTLE FURTHER NORTH INTO OUR AREA. EXPECT A BIT MORE
SUNSHINE MONDAY WITH TEMPERATURES AROUND 5 TO 10F ABOVE SEASONAL
NORMS. A FEW ISOLATED SHOWERS WILL BE POSSIBLE, BUT ONCE AGAIN, DO
NOT EXPECT MUCH RAINFALL.
PRECIPITATION POTENTIAL LOOKS MORE PROMISING DURING THE MIDDLE PART
OF THE WEEK. THE NOW CLOSED UPPER LEVEL LOW OVER THE WEST COAST WILL
PUSH NORTHEASTWARD AND EJECT INTO THE PLAINS MID-WEEK. THIS WILL
DELIVER TWO ADDITIONAL WINDOWS FOR PRECIPITATION, BOTH OF WHICH LOOK
BETTER (IF YOU WANT RAINFALL) COMPARED TO THE FIRST PHASE ON
SUNDAY/MONDAY. THE "DRY" (RELATIVELY) SLOT MOVES OUT AS ANOTHER
SURGE IN SOUTHWEST FLOW AND MID TO UPPER LEVEL MOISTURE PUSHES
PRECIPITABLE WATER BACK TO AROUND THE 97.5 PERCENTILE BY THE END OF
THE DAY TUESDAY. LOOK FOR SCATTERED SHOWERS DEVELOPING ACROSS THE
AREA TUESDAY CONTINUING INTO WEDNESDAY, SUPPORTED BY POTENT
ISENTROPIC LIFT AHEAD OF THE PRIMARY TROUGH AXIS. THERE IS A LITTLE
BIT OF UNCERTAINTY CONCERNING THE TIMING OF THE TROUGH AXIS,
BUT EXPECT THIS TO PUSH THROUGH SOMETIME BETWEEN WEDNESDAY AND
THURSDAY MORNING. THERE IS ALSO POTENTIAL FOR A BACK-EDGE ROUND
OF PRECIPITATION BEHIND THE UPPER LEVEL LOW, FORCED BY THE
DEVELOPMENT OF A TROWAL. THE QUESTION FOR THIS PERIOD OF TIME IS
HOW QUICKLY DOES THE SYSTEM EJECT, AND DOES IT MERGE BACK WITH
THE PRIMARY FLOW TO OUR NORTH BEFORE PASSING THROUGH OUR AREA.
THIS WILL DETERMINE EXACTLY HOW THE BACK EDGE OF PRECIPITATION
DEVELOPS, AND THE POTENTIAL FOR HIGH WINDS (MORE LIKELY THE
FASTER THE CLOSED LOW REJOINS THE PARENT TROUGH). OVERALL, THE
SECOND AND THIRD PHASE OF THIS EVENT LOOK MORE PROMISING IN
ENSEMBLE QPF, BUT THERE ARE A LOT OF WAYS FOR THESE INGREDIENTS
TO FAIL TO COME TOGETHER AND CAUSE OUR AREA TO MISS OUT ON
RAINFALL. CURRENT ENSEMBLE MEDIAN QPF IS AROUND 0.5 TO 0.75" FOR
MOST OF THE AREA, BUT CHANGES ARE NEARLY GUARANTEED AS WE GET
CLOSER TO THE EVENT. RELATIVELY FEW ENSEMBLE MEMBERS (PERHAPS
25%) HAVE ENOUGH COLD AIR WITH THIS SYSTEM TO DROP SNOW LEVELS
INTO POPULATED AREAS OF SOUTHEAST WYOMING, BUT SOME LIGHT SNOW
ABOUT 9000 FT IN ELEVATION APPEARS LIKELY. WE WILL GET A COOL
DOWN WITH THIS SYSTEM REGARDLESS OF THE PRECISE OUTCOME. THE
MOST LIKELY SCENARIO BRINGS TEMPERATURES BACK TO NEAR SEASONAL
NORMS ON TUESDAY AND WEDNESDAY, AND THEN POSSIBLY BELOW SEASONAL
NORMS FOR THURSDAY AND FRIDAY. A FREEZE IS LIKELY (50 TO 75%
PROBABILITY) FOR DOUGLAS, RAWLINS, AND LARAMIE BY FRIDAY
MORNING, AND POSSIBLE (20 TO 50%) FOR REMAINING PORTIONS OF THE
AREA.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 526 PM MDT FRI OCT 9 2026
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD, WITH GUSTY WINDS
BEING THE MAIN HAZARD OVER THE NEXT 24 HOURS. BREEZY WSW WINDS WITH
PEAK GUSTS UP TO 35-40 KNOTS ARE EXPECTED TO PERSIST THROUGH THE
OVERNIGHT HOURS INTO TOMORROW AT KRWL, WITH THE OTHER SITES
EXPERIENCING A DECREASE IN WINDS BELOW 15 KNOTS INTO THE NIGHT. FOR
TOMORROW, EXPECT AN OVERALL INCREASE IN CLOUDS FROM SOUTHWEST TO
NORTHEAST THROUGHOUT THE AFTERNOON AHEAD OF OUR NEXT UPPER-LEVEL
DISTURBANCE. INTRODUCED A PROB30 GROUP FOR -SHRA AT KRWL AFTER 21Z
WHERE SHOWER COVERAGE WILL BE HIGHEST.
CYS WATCHES/WARNINGS/ADVISORIES
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ417>422-
425-427-432.
FIRE WEATHER WATCH SATURDAY AFTERNOON FOR WYZ433.
NE...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR NEZ434.
FIRE WEATHER WATCH SATURDAY AFTERNOON FOR NEZ434>437.
SHORT TERM...MM
LONG TERM...MN
AVIATION...NB
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