675
FXUS65 KRIW 041131
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
531 AM MDT MON MAY 4 2026
KEY MESSAGES
- THE NEXT WEATHER SYSTEM BRING VALLEY/BASIN RAIN AND MOUNTAIN
SNOW FOR MONDAY AND TUESDAY WITH MINIMAL IMPACTS EXPECTED.
- COLDER TEMPERATURES THROUGH THE WEEK RESULTING IN FREEZE
WATCHES TO CONTINUE FOR LOWER ELEVATIONS EAST OF THE DIVIDE
FOR TUESDAY NIGHT BEING THE COLDEST MORNING GOING FORWARD.
- ANOTHER SYSTEM SKIRTS ACROSS THE NORTH AND EAST THURSDAY INTO
FRIDAY WITH ADDITIONAL PRECIPITATION CHANCES EXPECTED
(20-40%).
DISCUSSION
ISSUED AT 200 AM MDT MON MAY 4 2026
IR CURRENTLY DEPICTS A CLOSED LOW TO THE SOUTHWEST NEAR
CALIFORNIA AS WV SHOWS THE PFJ DIPPING FURTHER SOUTH OUT OF
CANADA AND MONTANA INTO NORTHEASTERN PORTIONS OF THE STATE.
CURRENT MODEL TRENDS CONTINUE THE SOUTHWARD PROGRESSION OF THE
JET WITH A JET MAX OF 120KTS PUSHING INTO THE NEXT SHORTWAVE
EXPANDING ACROSS MUCH OF THE CWA FOR MONDAY. THIS WILL DROP A
COLD FRONT THROUGH THE AREA IN THE MORNING HOURS THAT WILL SEE
COOLER TEMPERATURES FROM SUNDAY AROUND 10 TO 15 DEGREES FOR
AFTERNOON HIGHS. OTHERWISE, SCATTERED RAIN SHOWERS EXPECTED WITH
THE FRONT THAT WILL EXPAND INTO THE EVENING AND OVERNIGHT HOURS
AS THE SHORTWAVE PROGRESSIVELY MOVES ACROSS THE CWA. MINIMAL
IMPACTS EXPECTED WITH ANY SNOW ACCUMULATIONS CONSTRAINED TO
HIGHER ELEVATIONS EVEN ABOVE MOUNTAIN PASSES.
TUESDAY WILL SEE A MORE WIDESPREAD MOUNTAIN SNOW/VALLEY RAIN
EFFECT AS THE AFOREMENTIONED LOW TO THE SOUTHWEST WILL EMBED
INTO THE POSITIVELY TILTED TROUGH EXTENDING FROM THE DAKOTAS.
MORE AMPLE DIVERGENCE ALOFT EXPECTED, ESPECIALLY ACROSS THE
SOUTHERN HALF OF THE CWA WHERE QPF AMOUNTS COULD PUSH OVER A
QUARTER INCH (60-70%) IN SOME SPOTS ALONG THE I-80 CORRIDOR OF
SWEETWATER COUNTY AND POINTS SOUTH TO THE COLORADO BORDER.
OTHERWISE, SNOWFALL RATES FOR THE HIGHER ELEVATIONS WILL BE
GREATEST DURING THE AFTERNOON AND INTO THE EVENING HOURS.
MINIMAL IMPACTS EXPECTED TO MOUNTAIN PASSES (SOUTH PASS THE ONLY
ONE TO PUSH ADVISORY LEVEL AMOUNTS). HOWEVER, WITH THE WARM
TEMPERATURES AHEAD OF THIS SYSTEM AND MORE OF A LONGER DURATION
TIME FRAME, ANY ISSUANCES WERE HELD OFF AT THIS TIME FOR TUESDAY
AND TUESDAY NIGHT. HOWEVER, A REINFORCEMENT OF COOLER AIR
EXPECTED INTO WEDNESDAY MORNING SEEING A WIDESPREAD BELOW
FREEZING EVENT FOR BASINS EAST OF THE DIVIDE. AS SUCH, FREEZE
WATCHES CONTINUE WITH THIS BEING THE COLDEST MORNING OF THE WEEK
AHEAD.
ADDITIONAL PRECIPITATION CHANCES WITH MINIMAL IMPACTS EXPECTED
THURSDAY AND THURSDAY NIGHT AS THE MAIN TROUGH EXITS TO THE
EAST. THIS WILL GIVE WAY TO UPPER LEVEL RIDGING TO BUILD BACK IN
FRIDAY AND INTO THE WEEKEND WITH DRY CONDITIONS AND A WARMING
TREND EXPECTED. NORTHWEST FLOW ALOFT EXTENDS THROUGH INTO EARLY
NEXT WEEK WITH A MINOR SHORTWAVE PUSHING TO THE NORTHEAST
SATURDAY AFTERNOON THAT MIGHT SEE SOME SPORADIC SHOWERS FOR THE
BIGHORNS AND NORTHEASTERN COUNTIES, BUT MUCH OF THE ACTIVITY
WILL REMAIN NORTHEAST.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 530 AM MDT MON MAY 4 2026
VFR CONDITIONS TO START THE PERIOD AT ALL LOCATIONS. A SLOW
MOVING COLD FRONT IS PUSHING THROUGH NORTH TO SOUTH THROUGH THE
MORNING HOURS ALREADY THROUGH COD/WRL TURNING WINDS MORE
NORTHERLY. WINDS WILL INCREASE POST FRONTAL PEAKING AT 18-25KTS
AT ALL LOCATIONS. SHOWER ACTIVITY POSSIBLE IN THE AFTERNOON
WEST OF THE DIVIDE WITH THE BEST CHANCES FOR THUNDER AT RKS
AFTER 20Z THROUGH ABOUT 00Z. MORE WIDESPREAD SHOWERS AT ALL
LOCATIONS AFTER 00Z WITH DETERIORATING CONDITIONS THERE AFTER
THROUGH THE OVERNIGHT HOURS WITH MVFR CEILINGS LIKELY, AND EVEN
IFR FOR CPR/LND/RIW/RKS BY 08-09Z. THIS WILL BE THROUGH THE END
OF THE PERIOD INTO TUESDAY MORNING LIKELY TO STICK AROUND FOR
MUCH OF THE DAY.
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
FREEZE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING
FOR WYZ003>006-010-011-017-018-020.
DISCUSSION...LOWE
AVIATION...LOWE
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page