193
FXUS65 KCYS 112335
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
535 PM MDT TUE MAR 11 2025
KEY MESSAGES
- WARM, DRY, AND BREEZY WEATHER WILL CONTINUE THROUGH THURSDAY
WITH ELEVATED TO NEAR CRITICAL FIRE WEATHER CONDITIONS EACH
AFTERNOON.
- THE NEXT STORM SYSTEM WILL ARRIVE LATE THURSDAY INTO EARLY
SATURDAY, BRINGING STRONG WINDS AND A CHANCE FOR
PRECIPITATION. SOME SNOW ACCUMULATIONS ARE STILL POSSIBLE FOR
PARTS OF THE AREA.
SHORT TERM /THROUGH THURSDAY NIGHT/
ISSUED AT 333 PM MDT TUE MAR 11 2025
IT'S ANOTHER WARM AND DRY AFTERNOON ACROSS THE AREA. CURRENT GOES
SATELLITE IMAGERY SHOWS CLOUD COVER TO THE SOUTH ASSOCIATED WITH A
CLOSED LOW NEAR THE SOUTHERN CALIFORNIA COAST, AND CLOUD COVER TO
THE NORTH ASSOCIATED WITH THE NORTHERN BRANCH JET STREAM. DRIER AIR
IS POSITIONED IN BETWEEN ACROSS SOUTHERN WYOMING AND NEBRASKA, WITH
JUST ENOUGH UPPER LEVEL MOISTURE TO PRODUCE SOME MOUNTAIN WAVE
CIRRUS LEEWARD OF THE TERRAIN. LAST NIGHT'S WEAK COLD FRONT BROUGHT
HIGHER SURFACE DEWPOINTS INTO NORTHERN AND EASTERN PARTS OF THE
FORECAST AREA, BUT THIS DIDN'T QUITE REACH I-25. AS A RESULT,
CRITICAL FIRE WEATHER CONDITIONS ARE ONGOING ALONG THE I-25 CORRIDOR
FROM ROUGHLY WHEATLAND TO JUST NORTH OF CHEYENNE. EVEN THE LARAMIE
VALLEY IS NEAR CRITICAL, WHICH IS PRETTY UNUSUAL FOR MARCH.
HEADING INTO WEDNESDAY, EXPECT MORE OF THE SAME WITH HIGH
TEMPERATURES SIMILAR TO WHERE THEY ARE TODAY. WINDS WILL BE A LITTLE
BIT LIGHTER ALONG WITH SOME CLOUD COVER MAINLY OVER THE HIGHER
TERRAIN AND IN THE SOUTHERN PORTION OF THE AREA, THANKS TO THE
CLOSED LOW SKIRTING TO OUR SOUTH. BY WEDNESDAY NIGHT, THE NEXT
POWERFUL PACIFIC TROUGH WILL BEGIN DIGGING INTO THE WEST COAST, AND
INCREASING SOUTHWEST FLOW ALOFT HERE AS THE DOWNSTREAM RIDGE
AMPLIFIES. PROBABILITIES FOR HIGH WINDS WILL INCREASE LATE WEDNESDAY
NIGHT INTO THURSDAY IN THE TYPICAL AREAS OF CARBON AND CONVERSE
COUNTY FAVORED BY SOUTHWEST FLOW TO AROUND 30 TO 50%. THE HIGHEST
PROBABILITIES WILL BE ALONG I-80 FROM RAWLINS TO ARLINGTON. LREF
MEDIAN 700-MB WINDS OVER RAWLINS REACH 51 KNOTS EARLY THURSDAY
MORNING WITH A DECENT SIGNAL FOR SUBSIDENCE. STRONG WARM AIR
ADVECTION WILL BOOST TEMPERATURES THURSDAY AFTERNOON ALONG AND EAST
OF THE LARAMIE RANGE, WITH ANOTHER SHOT AT 60S TO MID 70S. SNOWFALL
WILL INCREASE TOWARDS THE VERY END OF THE SHORT TERM PERIOD IN THE
MOUNTAINS AS THE STRONG COLD FRONT PUSHES THROUGH EARLY FRIDAY
MORNING. MORE DETAILS ON THIS SYSTEM CAN BE FOUND IN THE LONG TERM
SECTION BELOW.
LONG TERM /FRIDAY THROUGH TUESDAY/
ISSUED AT 333 PM MDT TUE MAR 11 2025
THE FAIRLY QUIET WEEK WILL END ABRUPTLY ON FRIDAY AS STACKED
COLORADO LOW DEVELOPS EAST OF THE ROCKY MOUNTAINS OVER EASTERN
COLORADO. VERY STRONG 500MB CYCLONIC VORTICITY ADVECTION WILL HELP
THIS SYSTEM EJECT OFF THE THE NORTHEAST FAIRLY QUICKLY DURING THE
DAY FRIDAY, BUT NOT BEFORE WINDS AND THE CHANCE FOR SNOW RETURNS TO
SOUTHEAST WYOMING AND WESTERN NEBRASKA. THE SURFACE LOW WILL RAPIDLY
STRENGTHEN, POTENTIALLY APPROACHING BOMBCYCLOGENESIS CRITERIA, FROM
THE EARLY MORNING HOURS FRIDAY INTO THE EARLY MORNING HOURS ON
SATURDAY. CURRENT GUIDANCE DOES NOT SUGGEST THIS SYSTEM ACTUALLY
REACHING BOMBCYCLOGENESIS STATUS, BUT IT WILL BE A STRONG SYSTEM
IMPACTING THE REGION. FORCING WITH THIS SYSTEM WILL BE FAIRLY
STRONG, DUE TO AMPLE MOIST, ISENTROPIC LIFT ACROSS THE WESTERN ZONES,
INCLUDING THE SIERRA MADRE AND SNOWY RANGES. ADDITIONALLY, DECENT
FRONTOGENESIS WILL BE PRESENT WITH THIS SYSTEM, FURTHER FAVORING
SNOWFALL ACROSS MAINLY THE WESTERN ZONES WITH SOME LIGHT
ACCUMULATIONS EAST OF THE LARAMIE RANGE. DUE TO THE QUICK
PROPAGATION OF THIS SYSTEM, MAJOR SNOWFALL IMPACTS ARE NOT EXPECTED
ACROSS THE REGION. CURRENT SNOW ACCUMULATION FORECAST IS LESS THAN
AN INCH FOR MOST LOCATIONS. ONE THING THAT DOES LOOK TO BE FAIRLY
IMPACTFUL WILL BE THE WINDS WITH THIS SYSTEM. AS THE SURFACE LOW
RAPIDLY STRENGTHENS, SURFACE PRESSURE GRADIENTS AND 700MB HEIGHT
GRADIENTS RESPOND BY STRENGTHENING. AS A RESULT, A 55 TO 60KT 700MB
JET DEVELOPS OVERHEAD FROM ABOUT THE I-80 SUMMIT EASTWARD THROUGH
THE SOUTHERN NEBRASKA PANHANDLE. STRONG WINDS WILL MIX DOWN TO THE
SURFACE, LIKELY RESULTING IN HIGH WIND WARNING CRITERIA GUSTS AS THE
SYSTEM DEEPENS. DID NOT DO ANY HIGH WIND WATCHES AS OF NOW, DUE TO
THIS EVENT STILL BEING A FEW DAYS OUT. HOWEVER, THIS WIND EVENT WILL
CONTINUE TO BE MONITORED AND WATCHES MAY BE ISSUED IN FUTURE
FORECAST PACKAGE UPDATES.
AS THE SYSTEM QUICKLY EJECTS OFF TO THE EAST, RESIDUAL UPPER-LEVEL
TROUGHING WILL REMAIN ACROSS THE REGION AS AN UPPER-LEVEL RIDGE
DEVELOPS OVER THE WESTERN CONUS. NORTHWESTERLY FLOW WILL DEVELOP
ALOFT BETWEEN THESE TWO FEATURES LEAVING THE DOOR OPEN FOR EMBEDDED
DISTURBANCES AND PERIODIC PRECIPITATION CHANCES FOR THE MOUNTAINS.
MOUNTAIN SNOWFALL CHANCES WILL CONTINUE THROUGH SUNDAY EVENING,
LEADING TO A FEW ADDITIONAL INCHES OF SNOW FOR THE SIERRA MADRES AND
SNOWIES. AS THE UPPER-LEVEL RIDGE CONTINUES TO DEVELOP AND MOVE
TOWARDS THE REGION SATURDAY AND SUNDAY, A RIDGE WILL DEVELOP AT
700MB BY SUNDAY EVENING, WITH THE REGION BEING JUST SOUTH OF THE
APEX OF THE RIDGE, LEADING TO ZONAL, WESTERLY FLOW. THE LOW THAT
PREVIOUSLY IMPACTED THE REGION WILL TAKE A STRONG NORTHERLY TURN
SATURDAY AFTERNOON INTO THE EVENING HOURS LEADING TO AN INCREASING
700MB JET OVER THE NORTHERN MIDWEST BY SUNDAY AFTERNOON. AS A
RESULT, 700MB HEIGHT GRADIENTS WILL STRENGTHEN SUNDAY AFTERNOON INTO
EARLY MONDAY MORNING. AS A RESULT, A 55 TO 60KT 700MB JET DEVELOPS
ACROSS THE LARAMIE RANGE SUNDAY EVENING INTO EARLY MONDAY MORNING,
LEADING TO A SECONDARY SHOT OF HIGH WINDS ACROSS THE TYPICAL WIND
PRONE AREAS. SOUTHWESTERLY FLOW AT 700MB ACROSS WESTERN ZONES WILL
FAVOR HIGH WINDS OFF THE WEST AND NEAR THE ARLINGTON WIND PRONE
REGION DURING THE SAME TIME. STRONG WINDS WILL CONTINUE THROUGH
EARLY TUESDAY MORNING. WITH STRONG DOWNSLOPING WINDS AND A RIDGE
ALOFT, TEMPERATURES ON MONDAY WILL BE WELL ABOVE AVERAGE FOR MUCH OF
THE REGION. TEMPERATURES WEST IF I-25 WILL BE IN THE LOW- TO MID-
50S, WHILE TEMPERATURES EAST OF I-25 WILL BE IN THE UPPER-50S TO
UPPER-60S.
THE UPPER-LEVEL RIDGE WILL QUICKLY BE PUSHED OFF TO THE EAST
STARTING EARLY TUESDAY MORNING AS AN UPPER-LEVEL TROUGH DIGS INTO
THE PACIFIC NORTHWEST EARLY TUESDAY MORNING. THIS TROUGH LOOKS TO
BRING THE NEXT CHANCE FOR WIDESPREAD SNOWFALL. THIS SYSTEM IS
EXPECTED TO BE FAIRLY WELL STACKED BY TUESDAY AFTERNOON AS THE NEXT
COLORADO LOW DEVELOPS OFF OF THE ROCKIES IN EASTERN COLORADO.
CURRENT MODEL GUIDANCE SUGGESTS A FAVORABLE TRACK FOR PRECIPITATION
ACROSS SOUTHEAST WYOMING AND WESTERN NEBRASKA. THIS FORECAST WILL
LIKELY CHANGE IN THE COMING DAYS, BUT IT WILL CONTINUE TO BE
MONITORED WITH FUTURE FORECAST UPDATES.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 531 PM MDT TUE MAR 11 2025
VFR CONDITIONS WILL DOMINATE AT ALL TERMINALS THROUGH THE
PERIOD. BREEZY LATE AFTERNOON CONDITIONS WILL DIMINISH TO UNDER
10 KNOTS AT ALL TERMINALS BY 2-3Z. HIGH CIRRUS CLOUDS WILL DRIFT
WEST TO EAST OVER ALL TERMINALS. ANOTHER DAY OF VFR ON WEDNESDAY
WITH GENERALLY LIGHT WESTERLY WINDS EXPECTED AT ALL TERMINALS.
CYS WATCHES/WARNINGS/ADVISORIES
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ430-432.
NE...NONE.
SHORT TERM...MN
LONG TERM...AM
AVIATION...MAC
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page