531
FXUS65 KRIW 191804
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1204 PM MDT MON OCT 19 2026
KEY MESSAGES
- A MOSTLY CLEAR SKY TODAY, WITH PLEASANT HIGH TEMPERATURES IN
THE 60S, TO NEAR 70 DEGREES AROUND THE BIGHORN BASIN AND
JOHNSON COUNTY.
- A WEAK SYSTEM PUSHES ACROSS TUESDAY WITH ISOLATED SHOWER
ACTIVITY (~20%) ACROSS HIGHER TERRAIN, MAINLY WEST OF THE
DIVIDE. NO SIGNIFICANT IMPACTS EXPECTED.
- A WEATHER SYSTEM BRINGS GUSTY WINDS THURSDAY AND FRIDAY, WITH
RAIN AND HIGH ELEVATION SNOW LATE THURSDAY THROUGH FRIDAY.
CONFIDENCE IN DETAILS IS LOW AT THIS TIME.
DISCUSSION
ISSUED AT 130 AM MDT MON OCT 19 2026
IR CURRENTLY DEPICTS MAINLY CLEAR SKIES INTO MONDAY MORNING
WITH SOME PASSING CLOUDS THROUGH SWEETWATER COUNTY PUSHING EAST
BY SUNRISE. WATER VAPOR SHOWS WEAK UPPER LEVEL SOUTHWEST FLOW
ACROSS THE CWA WITH THE MAIN FINGER OF THE PFJ WELL TO THE NORTH
SUPPORTING A LOW OFF THE PACIFIC NORTHWEST COAST. THIS WILL
DEEPEN WITH ITS SOUTHWARD PROGRESSION MONDAY INTO TUESDAY WITH
INCREASING DIVERGENCE ALOFT. SEASONABLE TEMPERATURES AND
RELATIVELY LIGHT OR MODEST WINDS 10 TO 20 MPH THROUGH MID WEEK
EXPECTED. A WEAK SHORTWAVE WILL PROPAGATE ACROSS THE SOUTHWEST
FLOW TUESDAY AFTERNOON AND EVENING THAT WILL BRING ISOLATED
SHOWER ACTIVITY FOR HIGHER TERRAIN, MAINLY WEST OF THE DIVIDE.
LOW COVERAGE IS EXPECTED ~20 PERCENT WITH NO SIGNIFICANT IMPACTS
EXPECTED.
AS THE AFOREMENTIONED LOW STARTS TO MOVE EAST ACROSS SOUTHERN
CALIFORNIA WEDNESDAY, MODELS INDICATE IT BECOMING MORE OF AN
OPEN AND MORE PROGRESSIVE WAVE. THIS WILL THEN PUSH ALONG THE
SOUTHWEST FLOW ACROSS THE UPPER ROCKIES NOT OF HIGH OF AN IMPACT
WITH ITS QUICKER MOVEMENT. HOWEVER, MODELS ARE NOT IN THE BEST
OF AGREEMENT AND QPF AMOUNTS FLUCTUATE WITH EACH MODEL RUN.
WITH THIS RUN, IT HAS BUMPED UP FOR MOUNTAIN SNOW, ESPECIALLY
FOR WESTERN MOUNTAINS BUT DOES INCLUDE THE BIGHORNS. WITH THE
SEASONABLE TO JUST ABOVE TEMPERATURES, EXPECT VALLEY/BASIN
RAIN, EVEN WEST OF THE DIVIDE BELOW 8-9KFT. THIS WILL BE THE
BIGGEST WEATHER EVENT TO KEEP AN EYE ON FOR HEADLINES GOING
FORWARD FOR LATE THURSDAY INTO FRIDAY, STRETCHING INTO THE
WEEKEND, ALL DEPENDENT ON HOW QUICKLY IT PROGRESSES WITH ITS
EAST TO NORTHEASTWARD MOVEMENT. BEYOND THAT, INDUCED RIDGING
WILL BE SHORT LIVED AHEAD OF ANOTHER LOW OFF THE PACIFIC
NORTHWEST EXTENDING IN FROM THE GOA THAT COULD BE MORE IMPACTFUL
WITH A MORE REINFORCED COLDER AIR AND LOWER FREEZING LEVELS.
STAY TUNED FOR UPDATED FORECASTS IN THE COMING DAYS, BUT ENJOY
THE QUIETER WEATHER LEADING UP TO LATER IN THE WORK WEEK.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1204 PM MDT MON OCT 19 2026
VFR FLIGHT CONDITIONS ARE EXPECTED THROUGH THE PERIOD. THERE MAY BE
A SHOWER OR TWO ACROSS FAR SOUTHWESTERN WYOMING THIS AFTERNOON
THOUGH NO TERMINAL IMPACTS ARE EXPECTED. WIND WILL REMAIN ON THE
LIGHTER SIDE, WITH KCPR THE ONLY LOCATION EXPECTED TO SEE OVER 10
KNOTS. MOISTURE ADVECTION INCREASES OVERNIGHT AS FLOW TURNS MORE
SOUTHWESTERLY. THIS WILL LEAD TO ISOLATED SHOWERS AND A
SCATTERED TO BROKEN CLOUD DECK ACROSS WESTERN WYOMING BY
SUNRISE.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...LOWE
AVIATION...MYERS
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