361
FXUS65 KCYS 130522
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1122 PM MDT TUE MAY 12 2026
KEY MESSAGES
- NEAR TO RECORD WARMTH EXPECTED WEDNESDAY UNDER HIGH PRESSURE
ALOFT. A FIRE WEATHER WATCH IS IN EFFECT WEDNESDAY FOR THE
NORTHERN NEBRASKA PANHANDLE.
- CRITICAL FIRE CONDITIONS POSSIBLE AGAIN ON THURSDAY AND FRIDAY
ALONGSIDE STRONG WINDS AND DRY CONDITIONS.
- NEXT CHANCE FOR PRECIPITATION RETURNS DURING THE WEEKEND
ALONGSIDE COOLER CONDITIONS.
SHORT TERM /THROUGH THURSDAY/
ISSUED AT 245 PM MDT TUE MAY 12 2026
AN UPPER-LEVEL RIDGE AXIS WILL SLIDE INTO THE CWA THROUGHOUT THE DAY
WEDNESDAY LEADING TO A WARM DAY ACROSS THE AREA. 700 MB TEMPERATURES
WILL CLIMB TO +14C WHICH IS ABOVE THE 97.5TH PERCENTILE FOR NAEFS
CLIMATOLOGY. THIS WILL LEAD TO HIGHS REACHING THE 80S TO LOW 90S AND
A FEW LOCATIONS POTENTIALLY BREAKING RECORD HIGHS. LARAMIE AND
RAWLINS WILL HAVE THE BEST CHANCE AT SETTING NEW RECORD HIGH
TEMPERATURES. ALTHOUGH THE AREA WILL BE UNDER THE INFLUENCE OF A
RIDGE, A TROUGH PASSING NORTH OF THE CWA WILL SEND VORTICITY MAXES
IN TO THE ROCKIES, PROVIDING ENERGY FOR STORMS TO DEVELOP DURING THE
AFTERNOON HOURS. MODEL SOUNDINGS SHOW A DECENT AMOUNT OF CAPE FOR
THUNDERSTORM DEVELOPMENT. SOUNDINGS ALSO SHOW A DEEPLY INVERTED-V
PROFILE WITH EXTREMELY DRY SURFACE AND LOW-LEVEL. DCAPE VALUES
ACROSS THE CWA ARE 1500 J/KG AND GREATER, LEADING TO THE THREAT OF
DRY MICROBURSTS. WIND GUSTS IN EXCESS OF 70 MPH CANNOT BE RULED OUT.
ALSO, LITTLE IF ANY PRECIPITATION WILL ACTUALLY MAKE IT TO THE
GROUND, LEADING TO DRY LIGHTNING CONCERNS. COVERAGE OF PRECIPITATION
WILL BE HARD TO GUAGE GIVEN THE STRENGTH OF THE RIDGE. A FEW
ISOLATED STORMS ARE LIKELY, HOWEVER IT IS POSSIBLE FOR COVERAGE TO
BE MORE SCATTERED, ESPECIALLY BY EARLY EVENING. HI-RES GUIDANCE
SHOWS SHOWERS LINGERING THROUGH THE OVERNIGHT HOURS, WITH THEM
DISSIPATING BY THURSDAY MORNING.
THURSDAY WILL BE A BIT DRIER, BUT COOLER THAN WEDNESDAY AS THE
TROUGH TO THE NORTH FLATTENS THE RIDGE. THE MORE ZONAL FLOW PATTERN
WILL LEAD TO STRONG DOWNSLOPING WESTERLY WINDS ACROSS THE FORECAST
AREA, WHICH WILL LEAD TO VERY DRY CONDITIONS. HIGH WINDS WILL BE
POSSIBLE ACROSS THE WIND PRONE AREAS EARLY THURSDAY MORNING THROUGH
THURSDAY AFTERNOON AS WINDS ALOFT REACH 60 KTS FROM STRONG MSLP AND
HEIGHT GRADIENTS. IN-HOUSE GUIDANCE EVEN SHOWS A 40 TO 50 PERCENT
CHANCE OF HIGH WINDS OCCURRING. DID NOT ISSUE ANYTHING AT THIS
TIME SINCE IT IS A LATE SEASON WIND EVENT AND WOULD LIKE TO SEE
A FEW MORE MODEL CYCLES FIRST. THE COMBINATION OF STRONG WINDS
AND LOW RELATIVE HUMIDITY WILL LEAD TO CRITICAL FIRE WEATHER
CONDITIONS.
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
ISSUED AT 245 PM MDT TUE MAY 12 2026
FRIDAY WILL BE LARGELY DOMINATED BY UPPER-LEVEL ZONAL
FLOW ACROSS MUCH OF THE REGION. TEMPERATURES WILL BE QUITE WARM
FRIDAY AND SATURDAY AS 700MB TEMPERATURES INCREASE ABOVE ABOUT 7 TO
10C EACH AFTERNOON. HIGHS ON FRIDAY ARE ANTICIPATED TO BE IN THE LOW-
70S TO MID-80S, WITH SATURDAY BEING SLIGHTLY WARMER IN THE MID-70S
TO LOW-90S. AFTERNOON MINIMUM HUMIDITY VALUES LOOK TO REMAIN QUITE
LOW FRIDAY AND SATURDAY, LIKELY BETWEEN 10 TO 15% EACH DAY. LUCKILY,
WINDS WILL BE ON THE LIGHTER SIDE ACROSS WESTERN NEBRASKA, WHERE
FUELS ARE READY TO BURN, AND BREEZIER ACROSS SOUTHEAST WYOMING,
WHERE GREEN-UP HAS DECREASED FIRE SPREAD POTENTIAL. THAT BEING SAID,
HOT AND DRY CONDITIONS MAY STILL FAVOR EASIER FIRE STARTS, THOUGH
RAPID FIRE SPREAD IS NOT ANTICIPATED AT THIS TIME. INSTABILITY WILL
START INCREASING SATURDAY AFTERNOON WITH THE CONTINUED, HOT PATTERN,
AS WELL AS A COLD FRONT PUSHING THROUGH THE AREA. AN ISOLATED
THUNDERSTORM OR TWO WILL BE POSSIBLE SATURDAY, ESPECIALLY ACROSS
WESTERN NEBRASKA, AS IS COMMON AS WE MOVE INTO THE SPRING AND SUMMER
MONTHS.
SATURDAY INTO SUNDAY, AN UPPER LEVEL TROUGH WILL PUSH ITS WAY INTO
THE PACIFIC NORTHWEST AND SEND A FRONT THROUGH THE INTERMOUNTAIN
WEST. SOME LOBES OF VORTICITY LOOKS TO ACCOMPANY THIS FRONT TO AIDE
IN THE SYNOPTIC LIFT TO HELP PRODUCE SOME WEAK SHOWERS IN THE LATE
AFTERNOON TO EVENING TIME PERIOD. BY SUNDAY AFTERNOON, THE TROUGH
BECOMES MORE POSITIVELY TILTED PUSHING SOME STRONG WARM AIR
ADVECTION AND VORTICITY LOBES TO GIVE US SOME POSSIBLY STRONG RAIN
SHOWERS THROUGH SUNDAY EVENING. AS THIS UPPER LEVEL TROUGH PUSHES
THROUGH THE INTERMOUNTAIN WEST SUNDAY NIGHT INTO MONDAY, THE 700MB
TEMPERATURE GRADIENT GOES FROM A WARM 8 TO 10C AND DROPS DOWN TO
ABOUT -6/-5C GIVING US A DECENT CHANCE FOR A RAIN/SNOW MIX TO
POSSIBLY SNOW SHOWERS IN THE HIGHER ELEVATIONS ABOVE 7,0000FT EARLY
MONDAY MORNING AND MONDAY NIGHT. DURING THE DAY THE SUMMER SUN IS
LIKELY TO KEEP ALL THE PRECIPITATION AS RAIN OUTSIDE THE MOUNTAIN
PEAKS FOR SOUTHEAST WYOMING. THIS TROUGH IS THE START OF AN ACTIVE
WEATHER PATTERN FOR THE WORK WEEK AS WE LOOK TO GET THE CHANCE FOR
PRECIPITATION ALMOST EVERY OTHER DAY.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1122 PM MDT TUE MAY 12 2026
VFR CONDITIONS WILL CONTINUE ACROSS ALL TERMINALS FOR THE DURATION
OF THIS TAF PERIOD. WINDS TONIGHT SHOULD REMAIN LESS THAN 15 KNOTS
ACROSS ALL THE SITES. BY 18Z WEDNESDAY, THERE WILL BE AN UPTICK OF
SOUTHERLY WINDS ACROSS SOUTHEAST WYOMING WITH WINDS GUSTING BETWEEN
25 AND 35 KNOTS. HOWEVER, THE TERMINALS ACROSS THE NEBRASKA
PANHANDLE WILL SEE WINDS INCREASE A BIT EARLIER, BY 15Z WEDNESDAY,
THESE SITES WILL SEE SOUTHERLY GUSTS INCREASING INTO THE 25 TO 35
KNOT RANGE.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR NEZ434-435.
SHORT TERM...SF
LONG TERM...MM
AVIATION...RZ
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