842
FXUS65 KCYS 051109
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
409 AM MST WED MAR 5 2025
KEY MESSAGES
- ANOTHER WINTER STORM WILL MOVE IN LATE WEDNESDAY NIGHT
THROUGH EARLY FRIDAY, THIS TIME MAINLY AFFECTING NORTHERN AND
CENTRAL PORTIONS OF THE FORECAST AREA.
- A RETURN TO MILD AND DRY CONDITIONS IS EXPECTED TO START
NEXT WEEK ALONGSIDE THE RETURN OF GUSTY WINDS.
SHORT TERM /THROUGH FRIDAY MORNING/
ISSUED AT 409 AM MST WED MAR 5 2025
TODAY, THE RIDGE WILL KEEP US SEASONAL WITH CLOUDS INCREASING IN THE
AFTERNOON. BY THE EVENING THE RIDGE BEGINS TO FLATTEN AS THE LOW
PRESSURE SYSTEM BEGINS TO ENTER THE ROCKY MOUNTAINS AND HIGH PLAINS.
THE WARM FRONT ASSOCIATED SYSTEM WILL ADVECT WARM AIR ACROSS OUR
REGION TO KICK START PRECIPITATION INTO CARBON COUNTY THEN BEGINS TO
MOVE EAST AHEAD OF THE PARENT SYSTEM. BY THURSDAY EVENING THE LOW
PRESSURE SYSTEM PERFORMS THE METEOROLOGY VERSION OF MITOSIS AS IT
CROSSES THE ROCKIES FORMING A MORE REINFORCING TROUGH OR TWO
SHORTWAVES AS ONE SLOWLY MIGRATES ACROSS THE INTERMOUNTAIN WEST AND
THE OTHER STARTING EJECTING INTO THE CENTRAL PLAINS. OVERALL THIS
WILL CONTINUE PRECIPITATION CHANCES THROUGH FRIDAY. GIVEN MODEL
CONSENSUS ON THE THE TRACK BETWEEN THE GLOBAL AND HI-RES MODELS
THERE IS PRETTY HIGH CONFIDENCE IN THE SYSTEM TRACK.
FOR HEADLINES, THE WINTER WEATHER WATCH WAS EXPANDED TO INCLUDE
CENTRAL CARBON COUNTY STARTING LATE WEDNESDAY NIGHT THROUGH FRIDAY
MORNING. GOSHEN COUNTY AS WELL AS THE NORTHERN HALF OF THE PANHANDLE
WAS PUT INTO A WATCH STARTING THURSDAY MORNING TO FRIDAY MORNING. HI-
RES GUIDANCE MAINTAINS A BAND OF MODERATE F-GEN OVER CARBON COUNTY
AS MOISTURE ADVANCES WITH THAT WARM FRONT TO GIVE US AN AREA OF
ENHANCED LIFT WITH A SOUTHWESTERLY FLOW THAT FAVORS AN UPSLOPE
REGIME TO DOUBLE DOWN ON THOSE POTENTIAL HEAVIER SNOW RATES. THE
HREF HAS THE 25TH/75TH PERCENTILE AS BETWEEN 4 TO 6 INCHES BY MIDDAY
THURSDAY PROJECTING A STRONG SIGNAL FOR THOSE HEAVIER RATES.
HOWEVER, WHEN COMPARING OMEGA FIELDS TO THE F-GEN FIELD HI-RES
GUIDANCE SHOWS THE FRONT STALLING NEAR THE SHIRLEY MOUNTAINS AND
NORTHERN LARAMIE RANGE THURSDAY MORNING, THIS PUTS POTENTIAL HEAVIER
BANDS OF SNOW TO RESIDE OVER THESE AREAS AS WELL. HI-RES GUIDANCE
DOES SHOW THE FRONT BEING PUSHED NORTH BY THE SECONDARY WAVE TO SEND
A POTENT BAND OF F-GEN COUPLED WITH STRONGER ISENTROPIC LIFT THROUGH
THE GOSHEN COUNTY AND INTO THE NORTHERN COUNTIES. FOLLOWING THE
TIMING OF THIS PUSH THAT IS WHY GOSHEN AND THE NORTHERN PANHANDLE
START AT 12Z THURSDAY. THE 25TH/75TH PERCENTILE IS BETWEEN 4 TO 7
INCHES BY THURSDAY NIGHT/FRIDAY MORNING. DURING THE SAME TIME PERIOD
THE HREF INCREASES THE 25TH/75TH OVER CARBON COUNTY TO 6 TO 10
INCHES. THE UNCERTAINTY IS HOW FAR SOUTH WILL THE HEAVIER SNOWFALL
WILL BE AND WHAT IS THE TOTAL ACCUMULATIONS WILL LOOK LIKE AS THIS
SYSTEM STARTS TO MOVE OFF FRIDAY MORNING. THIS UNCERTAINTY IS WHY
EVERYTHING WAS KEPT IN A WATCH FOR MODEL AND ENSEMBLE GUIDANCE A
LITTLE MORE TIME TO RESOLVE THE SYSTEM.
LONG TERM /FRIDAY THROUGH TUESDAY/
ISSUED AT 409 AM MST WED MAR 5 2025
MEDIUM/LONG RANGE MODELS IN VERY GOOD AGREEMENT LATE THIS WEEK
THROUGH EARLY NEXT WEEK. GENERAL QUIET WEATHER IS EXPECTED, BUT
WE WILL STILL BE DEALING WITH THE DEPARTING STORM SYSTEM AND
ASSOCIATED STATIONARY COLD FRONT EARLY ON FRIDAY. MODELS ARE
HANDING THIS SYSTEM MUCH BETTER THAN THE LAST ONE, WITH LIGHT
SNOWFALL CONTINUING THROUGH NOON FRIDAY AND FINALLY TAPERING TO
FLURRIES IN THE AFTERNOON. ADDITIONAL SNOW ACCUMULATION ON FRIDAY
SHOULD BE LESS THAN ONE INCH, WITH SLIGHTLY HIGHER AMOUNTS ON NORTH
FACING RIDGES. FORECAST CHALLENGES THEN SWITCH TO TEMPERATURES,
ESPECIALLY NORTH OF I-80 WITH AN SOLID SURFACE SNOWPACK AND
CLEARING SKIES FRIDAY NIGHT. EVEN ALONG I-80 WHERE THE LOWEST
SNOW TOTALS SHOULD BE, 25TH TO 50TH PERCENTILE LOWS ARE IN THE
LOW TO MID TEENS. FURTHER NORTH, SINGLE DIGITS ARE POSSIBLE
BELOW AND ABOVE ZERO, ESPECIALLY IN THE MORE SHELTERED AND
COLDER VALLEYS. LOWERED TEMPERATURES FRIDAY NIGHT/SATURDAY
MORNING AND BLENDED WITH NBM 10TH TO 25TH PERCENTILE...WHICH WAS
PRETTY CLOSE TO THE GEPS AND GEFS 25TH PERCENTILE LOWS.
AS WE HEAD INTO THE WEEKEND, ALL MODELS SHOW A HIGH AMPLITUDE
RIDGE ALOFT SLOWLY NUDGING EASTWARD FROM THE GREAT BASIN REGION.
EXPECT 700MB TEMPERATURES TO RECOVER WITH VALUES ABOVE 0C BY
SUNDAY. HOWEVER, AREAS WITH A DECENT SNOW PACK WILL STRUGGLE TO
RECOVER. LOWERED HIGH TEMPERATURES SATURDAY, AND TO A LESSER
EXTENT SUNDAY. KEPT HIGHS AROUND 4 TO 6 DEGREES BELOW GUIDANCE
IN MOST AREAS UP NORTH. WITH THE HIGHER MARCH SUN-ANGLE, EXPECT
SNOW TO MELT RELATIVELY FAST WITH MOSTLY SUNNY SKIES. LOWS
SUNDAY MORNING WILL LIKELY REMAIN IN THE LOW TO MID TEENS FOR
MUCH OF THE AREA, WITH LOWS AROUND 20 IN AREAS THAT HAVE LITTLE
OR NO REMAINING SNOW PACK. REGARDLESS, EXPECT HIGHS ON SUNDAY TO
BE NEAR OR SLIGHTLY ABOVE AVERAGE FOR THIS TIME OF THE YEAR.
ALONG WITH THE MILDER TEMPERATURES, WINDS WILL ALSO BEGIN TO
INCREASE OVER SOUTHEAST WYOMING LATE ON SUNDAY.
PRIMARY FORECAST CONCERNS FOR NEXT WEEK ARE THE POTENTIAL FOR
STRONG WINDS ACROSS THE WIND PRONE AREAS OF SOUTHEAST WYOMING
AND SOME ELEVATED FIRE WEATHER CONCERNS ALONG THE I-80 CORRIDOR.
ALL MODELS SHOW THE UPPER LEVEL RIDGE AXIS FLATTENING OUT
LATE SUNDAY AND MONDAY WITH INCREASING WINDS ALOFT. IT IS STILL
EARLY TO QUANTIFY HIGH WIND POTENTIAL, BUT 700MB FLOW INCREASES
OVER 45 KNOTS WITH INCREASING SURFACE PRESSURE GRADIENTS.
OUTSIDE OF THE WIND PRONE AREAS, EXPECT WINDY CONDITIONS ACROSS
SOUTHEAST WYOMING WITH BREEZY CONDITIONS OVER WESTERN NEBRASKA.
THE GOOD NEWS IS IT WILL WARM UP AS THE WARMING TREND CONTINUES.
FORECAST HIGH TEMPERATURES ON MONDAY ARE GENERALLY IN THE MID
50S TO MID 60S. SLIGHTLY COOLER ON TUESDAY AS THE NEXT PACIFIC
UPPER LEVEL TROUGH BEGINS TO MOVE TOWARDS THE NORTHERN AND
CENTRAL FRONT RANGE, BRINGING CLOUDS AND COOLER AIR ALOFT.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1022 PM MST TUE MAR 4 2025
NORTHWEST FLOW ALOFT WILL PREVAIL TONIGHT, THEN TURN WEST ON
WEDNESDAY.
WYOMING TAFS...SCATTERED TO BROKEN CLOUDS NEAR 6000 FEET WILL
CONTINUE UNTIL 09Z, THEN SCATTERED TO BROKEN CLOUDS NEAR
15000 WILL OCCUR UNTIL 00Z, THEN CEILINGS WILL BE NEAR
5000 FEET AT RAWLINS AFTER 00Z, AND FROM 12000 TO 15000 FEET AT
LARAMIE AND CHEYENNE AFTER 00Z. WINDS WILL GUST TO 30 KNOTS AT
ALL THE TERMINALS FROM 15Z TO 00Z.
NEBRASKA TAFS...MOSTLY CLEAR SKIES WILL OCCUR UNTIL 00Z, THEN
CEILINGS WILL BE NEAR 15000 FEET AFTER 00Z. WINDS WILL GUST TO
28 KNOTS AT ALLIANCE AND SIDNEY UNTIL 09Z TO 12Z.
CYS WATCHES/WARNINGS/ADVISORIES
WY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE THURSDAY
NIGHT FOR WYZ102-108.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE THURSDAY
NIGHT FOR WYZ101-103-106-107.
WINTER STORM WATCH FROM THIS EVENING THROUGH LATE THURSDAY
NIGHT FOR WYZ104-105-109.
NE...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE THURSDAY
NIGHT FOR NEZ002-003-095-096.
SHORT TERM...MM
LONG TERM...TJT
AVIATION...RUBIN
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