668
FXUS65 KCYS 190317
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
917 PM MDT FRI APR 18 2025
KEY MESSAGES
- WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES REMAIN IN
EFFECT THROUGH THIS EVENING. CONTINUED SNOWFALL EXPECTED
THROUGH THE DAY.
- WARMER AND SLIGHTLY DRIER SUNDAY THROUGH TUESDAY. WINDY
CONDITIONS POSSIBLE SUNDAY NIGHT AND MONDAY.
- ANOTHER PERIOD OF UNSETTLED WEATHER EXPECTED MID TO LATE
WEEK WITH NUMEROUS SHOWERS AND WIDELY SCATTERED THUNDERSTORMS.
SHORT TERM /THROUGH SATURDAY NIGHT/
ISSUED AT 210 PM MDT FRI APR 18 2025
RADAR RETURNS SHOW PRECIPITATION SLOWLY DECREASING ACROSS THE AREA
THIS AFTERNOON. MANY OF THE WINTER STORM WARNINGS WERE ABLE TO COME
DOWN EARLIER IN THE DAY, BUT A FEW WARNINGS AND WINTER WEATHER
ADVISORIES REMAIN IN PLACE UNTIL THIS EVENING TO ACCOUNT FOR AREAS
OF BLOWING SNOW AND SOME LINGERING SNOW. THESE REMAINING HEADLINES
LOOK ON TRACK TO COME DOWN ON TIME AS HI-RES GUIDANCE SHOWS SHOWER
ACTIVITY DYING DOWN BY THIS EVENING. SOME LINGERING SNOW SHOWERS AND
POTENTIALLY FOG WILL BE POSSIBLE OVERNIGHT ALONG THE INTERSTATE 80
CORRIDOR IN WYOMING.
HEADING INTO SATURDAY, THE UPPER-LEVEL TROUGH WILL STILL BE IN PLACE
OVER THE CWA. THIS MEANS THAT THE COLD, BELOW AVERAGE TEMPERATURES
WILL ALSO STAY IN PLACE. LOW TEMPERATURES SATURDAY MORNING WILL BE
QUITE COLD AS 700 MB TEMPERATURES SIT IN THE 10TH PERCENTILE OF
NAEFS CLIMATOLOGY. THIS ANOMALOUSLY COLD AIR WILL LEAD TO LOW
TEMPERATURES EARLY SATURDAY MORNING IN THE TEENS AND 20S.
TEMPERATURES IN WESTERN NEBRASKA WILL HEAT UP QUICKLY INTO THE 50S
DUE TO MOSTLY SUNNY SKIES AND MINIMAL SNOW COVER. SOUTHEAST WYOMING
WILL REMAIN ON THE CHILLIER SIDE WITH 40S ALONG THE INTERSTATE
25 CORRIDOR, AND UPPER 30S ALONG THE INTERSTATE 80 CORRIDOR.
TEMPERATURES OUT WEST WILL BE PARTICULARLY COLD DUE TO SNOW
COVER. ALTHOUGH CHANCES ARE SLIM, CANNOT RULE OUT A FEW SNOW
SHOWERS IN THE HIGH TERRAIN DURING THE DAY SATURDAY AS A
VORTICITY MAX HANGS OVER THE CWA WITH SOME LEFTOVER MID-LEVEL
MOISTURE. ANY SHOWERS THAT DO DEVELOP ARE NOT EXPECTED TO BE
IMPACTFUL. THE PRECIPITATION THREAT WILL TAPER OFF SATURDAY
NIGHT AS WINDS BECOME STRONGER AND MORE WESTERLY.
LONG TERM /SUNDAY THROUGH FRIDAY/
ISSUED AT 210 PM MDT FRI APR 18 2025
AN AREA OF SURFACE HIGH PRESSURE MOVES INTO THE
INTERMOUNTAIN WEST FOLLOWING THE TROUGH RESPONSIBLE FOR THE MOUNTAIN
PRECIPITATION ON SATURDAY. THIS RESULTS IN A WEAK UPPER LEVEL RIDGE
THAT ISN'T VERY AMPLIFIED AND EASILY FLATTENED. ANOTHER SHORTWAVE
STARTS TO PUSH INTO OUR REGION MONDAY MORNING. THIS SHORTWAVE IS
PRETTY WEAK AND NOT LIKELY TO OVERCOME THE DOWNSLOPING WESTERLY
FLOW. LOOKING AT MODEL SOUNDINGS, THERE IS A LITTLE BIT OF
SATURATION IN THE MID LEVELS AND A STOUT DRY LAYER IN THE LOWER
LEVELS. VIRGA SEEMS THE MORE LIKELY RESULT OF THIS SHORTWAVE GIVEN
THE ENVIRONMENT. HOWEVER, THE RAIN CHANCES MAY NOT REALLY OCCUR UNTIL
MONDAY NIGHT INTO TUESDAY MORNING AS IT WILL BE EASIER TO SATURATE
IN THE OVERNIGHT PERIOD AND IN THE MORNING. TUESDAY THROUGHOUT THE
DAY LOOKS RATHER DRY AS THE DRY LOWER LAYER REMAINS IN THE MODEL
SOUNDINGS. WEDNESDAY BECOMES VERY MUDDLED IN THE LONG TERM. THE
DETERMINISTIC MODELS HAVE REACHED AN AGREEMENT OF THE POSSIBILITY OF
SHOWERS FORMING ALONG THIS SOUTHERN BOUNDARY. HOWEVER, IT SEEMS LIKE
THE MOISTURE ADVECTION DOESN'T REACH OUR AREA UNTIL LATE WEDNESDAY
MORNING WITH THE STRONGER FORCING TO THE NORTH OF OUR FORECAST AREA.
NAEFS PLACES PWAT VALUES BETWEEN 0.25 AND 0.35 INCHES ACROSS THE
STATE OF WYOMING AND 0.35 TO 0.50 VALUES FOR THE NEBRASKA PANHANDLE
AROUND 18Z WED. SO ITS MORE LIKELY IF SHOWERS DO OCCUR WEDNESDAY
THEY WOULD BE MORE LIKELY IN THE AFTERNOON DURING THE STRONGEST
MOISTURE CONTENT AND PEAK HEATING FOR SOME POSSIBLE AFTERNOON GARDEN
VARIETY THUNDERSTORMS. THE GLOBAL MODELS LOOK TO THROW IN A COUPLE
HUNDRED JOULES OF CAPE IN THE AFTERNOON AND EVENING.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 912 PM MDT FRI APR 18 2025
A TROUGH ALOFT WILL REMAIN OVER THE TERMINALS THROUGH SATURDAY.
WYOMING TAFS...FOR RAWLINS, SCATTERED CLOUDS NEAR 4500 FEET WILL
OCCUR UNTIL 15Z SATURDAY, THEN SKIES WILL BE CLEAR.
FOR LARAMIE AND CHEYENNE, SCATTERED TO BROKEN CLOUDS FROM
4000 TO 8000 FEET WILL OCCUR, WITH FOG REDUCING VISIBILITIES TO
4 MILES AND CEILINGS TO 1500 FEET AT CHEYENNE FROM 09Z TO 14Z.
WINDS WILL REMAIN 13 KNOTS OR LESS.
NEBRASKA TAFS...SCATTERED TO BROKEN CLOUDS FROM 6000 TO
9000 FEET WILL PREVAIL. WINDS WILL REMAIN 10 KNOTS OR LESS.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...SF
LONG TERM...MM
AVIATION...RUBIN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page