958
FXUS65 KRIW 211112
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
412 AM MST FRI FEB 21 2025
KEY MESSAGES
- WARMING AND DRY TREND FRIDAY AND SATURDAY.
- POSSIBLE ICE JAMMING AND FLOODING DUE TO WARMING TEMPERATURES
SUNDAY THROUGH TUESDAY ACROSS THE BIGHORN BASIN AND JOHNSON
COUNTY.
- NEXT DISTURBANCE WILL PUSH IN SUNDAY THROUGH MID WEEK WITH
POTENTIAL FOR ADVISORY LEVEL SNOW ACROSS WESTERN MOUNTAINS.
DISCUSSION
ISSUED AT 1230 AM MST FRI FEB 21 2025
IR CURRENTLY DEPICTS CLEARING SKIES ACROSS MUCH OF THE STATE AS
UPPER LEVEL RIDGING BUILDS IN FROM THE WEST. SOME COOLER CLOUD
TOPS ACROSS FAR SOUTHERN REACHES OF THE CWA ALONG THE COLORADO
STATE LINE WITH SOME LIGHT LINGERING SNOW FLURRIES PUSHING OUT.
THE MAIN FINGER OF THE PFJ CONTINUES TO STAY TO THE NORTHEAST
DIVING INTO THE GREAT PLAINS KEEPING THE COLDER TEMPERATURES
AWAY. THE WEAK DISTORTION OF THE JET DIVING SOUTH OF THE CWA
HAS SUPPORTED THIS PREVIOUS DISTURBANCE THAT NOW WILL PUSH TO
THE SOUTHEAST GIVING WAY TO TRANQUIL WEATHER CONDITIONS FOR
FRIDAY AND INTO THE WEEKEND. INCREASING UPPER LEVEL CONVERGENCE
WILL ALLOW FOR HIGHER PRESSURE AT THE SURFACE AND WARMING
TEMPERATURES EVEN INTO EARLY NEXT WEEK. AS A RESULT, THE MAIN
CONCERN WILL BE FOR ICE JAMMING AND FLOODING FOR AREA IN
NORTHERN BIGHORN BASIN AND JOHNSON COUNTY DUE TO THE RECENT
SNOWPACK IN LOWER ELEVATIONS. TEMPERATURES EAST OF THE DIVIDE
WILL PUSH INTO THE 40S FRIDAY AND SATURDAY AND 50S TO NEAR 60
SUNDAY THROUGH TUESDAY. WEST OF THE DIVIDE WILL REMAIN IN THE
30S FOR MUCH OF THIS TIME AS THE NEXT DISTURBANCE WILL START TO
AFFECT THESE AREAS COME SUNDAY THROUGH MID WEEK.
THE MAIN PFJ DIPS FURTHER SOUTH ACROSS MONTANA TO NORTHERN
REACHES OF WYOMING BY SUNDAY AFTERNOON GIVING WAY TO THE PACIFIC
NORTHWEST MOISTURE ONCE AGAIN. THIS WILL INCREASE SNOW CHANCES
WEST OF THE DIVIDE, MAINLY FOR THE WESTERN MOUNTAINS THROUGH MID
WEEK. A MIX TO EVEN JUST LIQUID PRECIPITATION POSSIBLE FOR THE
LOWER VALLEYS AS TEMPERATURES COULD REMAIN ABOVE THE FREEZING
MARK FOR MUCH OF THIS PERIOD. TIME WILL TELL, BUT A FORWARD LOOK
ON SNOW ACCUMULATIONS LOOK TO BE MODEST AT BEST TO POSSIBLE
ADVISORY LEVEL CRITERIA FOR THE WESTERN MOUNTAINS TO INCLUDE THE
MAIN PASSES AS PER USUAL WITH THE ZONAL WESTERLY FLOW. THE MAIN
TROUGH LOOKS TO PASS THROUGH THE REST OF THE STATE TO THE EAST
LATE TUESDAY AND INTO EARLY WEDNESDAY THAT WILL GIVE REALLY THE
ONLY CHANCE FOR PRECIPITATION EAST OF THE DIVIDE IN THE LONG
TERM PERIOD. WITH THE WARMER TEMPERATURES ABOVE FREEZING
(ALTHOUGH COOLER TUESDAY AND WEDNESDAY) LIQUID RAIN THE LIKELY
PRECIPITATION FOR THE LOWER ELEVATIONS AND LIKELY SNOW FOR THE
BIGHORNS. OTHERWISE, RIDGING BUILDS BACK IN FOR THE REMAINDER OF
THE WEEK AND INTO THE FOLLOWING WEEKEND WITH DECREASED
DIVERGENCE ALOFT LOOKING TO BE A POSSIBLE OMEGA BLOCK TO END
THE REST OF THE MONTH AND INTO MARCH. WINTER IS STILL NOT DONE,
BUT IT IS IN ITS WANING HOURS IN THE LONGER TERM OUTLOOK.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 410 AM MST FRI FEB 21 2025
DRY WEATHER IS EXPECTED THIS TAF PERIOD AS SURFACE HIGH PRESSURE
BUILDS INTO THE INTERMOUNTAIN WEST. AS OF 11Z, A LOW- TO MID- LEVEL
VFR STRATUS DECK HAS STAYED PRESENT ACROSS WYOMING OVERNIGHT AND IS
EXPECTED TO REMAIN VFR AT ALL TERMINALS EXCEPT KPNA THIS
MORNING. KPNA CAN EXPECT JUMPS BETWEEN VFR AND MVFR CEILINGS
THROUGH 16Z. AT KJAC, IF THE STRATUS DECK CAN DISSIPATE BY
AROUND 12Z, THERE IS POTENTIAL FOR FOG TO DEVELOP UNDER CLEAR
SKIES. THERE IS A 50% CHANCE IN MVFR VISIBILITIES DUE TO FOG
THROUGH 18Z AT KJAC.
ALL TERMINALS WILL BE VFR BY 18Z AT THE LATEST WITH CLEARING SKIES.
WINDS REMAIN LIGHT BEFORE INCREASING THIS AFTERNOON INTO THE EVENING
WITH GUSTS AROUND 20 KNOTS EXPECTED AT KRKS AND KCOD.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC FOR
THE LATEST INFORMATION ON ICING AND TURBULENCE FORECASTS.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...LOWE
AVIATION...GERHARDT
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