507
FXUS65 KRIW 031945
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
145 PM MDT SUN MAY 3 2026
KEY MESSAGES
- REMAINING WARM AND MOSTLY DRY TODAY, BUT THERE WILL BE
SCATTERED VIRGA SHOWERS THIS AFTERNOON AND A LOW CHANCE
(15-20%) OF A RAIN SHOWER ACROSS NORTHERN WYOMING. GUSTY
DOWNDRAFTS TO 50 MPH POSSIBLE (40%) THROUGH THE AFTERNOON.
- ELEVATED FIRE WEATHER CONDITIONS CONTINUE TODAY DUE TO VERY
DRY CONDITIONS, ESPECIALLY FOR THE SOUTHERN HALF OF THE AREA.
- THE NEXT WEATHER SYSTEM MOVES ACROSS THE STATE MONDAY AND
TUESDAY, BRINGING A BETTER OPPORTUNITY FOR RAIN AND SNOW.
CONFIDENCE REMAINS LOW IN RAINFALL AND SNOWFALL AMOUNTS.
- FREEZE WATCHES NOW IN EFFECT FOR LOWER ELEVATIONS EAST OF THE
CONTINENTAL DIVIDE TUESDAY NIGHT INTO WEDNESDAY MORNING.
UPDATE
ISSUED AT 144 PM MDT SUN MAY 3 2026
ISOLATED STORMS HAVE BEEN DEVELOPING ALONG THE EASTERN SLOPES OF THE
BIGHORN MOUNTAINS AND SLIDING SOUTHEAST THROUGH JOHNSON COUNTY THIS
MORNING AND INTO THIS AFTERNOON. THIS WILL CONTINUE THROUGH THE
AFTERNOON HOURS, WITH MORE ISOLATED STORMS AND SCATTERED
SHOWERS DEVELOPING ACROSS NORTHERN PORTIONS OF THE AREA THIS
AFTERNOON. WIDESPREAD SCATTERED VIRGA SHOWERS WILL DEVELOP
ACROSS THE AREA THIS AFTERNOON AS WELL, WITH GUSTY DOWNDRAFT
WIND ASSOCIATED WITH THEM. GUSTS COULD BE AS HIGH AS 50 MPH DUE
TO LARGE TEMPERATURE DEWPOINT SPREADS THIS AFTERNOON. THE DRY
CONDITIONS COMBINED WITH GUSTY DOWNDRAFTS WILL LEAD TO CONTINUED
ELEVATED FIRE WEATHER CONDITIONS TODAY. MOISTURE MOVES IN
TOMORROW, WHICH WILL LEAD TO AN IMPROVEMENT IN FIRE WEATHER
CONDITIONS. FORECAST REMAINS ON TRACK FOR A COLD FRONT TO PUSH
THROUGH MONDAY INTO MONDAY NIGHT, WITH SCATTERED RAIN SHOWERS
AND THUNDERSTORMS FOCUSED FROM CENTRAL TO SOUTHERN PORTIONS OF
THE AREA. MODEL GUIDANCE KEEPS DECREASING QPF AMOUNTS LITTLE BY
LITTLE, BUT WHERE STORMS SET UP WILL STILL RECEIVE AROUND 0.5"
AND UP TO 1" OF RAIN. OF NOTE FOR TUESDAY AFTERNOON IS THE
POTENTIAL FOR SOME STRONGER STORMS ACROSS SOUTHWEST WY. FREEZE
WATCHES HAVE BEEN ISSUED FOR TUESDAY NIGHT INTO WEDNESDAY
MORNING FOR LOWER ELEVATIONS EAST OF THE CONTINENTAL DIVIDE,
WITH WIDESPREAD LOW TEMPERATURES OF 20-30 F.
DISCUSSION
ISSUED AT 211 AM MDT SUN MAY 3 2026
THE MORE PROGRESSIVE PATTERN CONTINUES ACROSS THE NORTHERN
ROCKIES DURING THE NEXT WEEK. TODAY WILL START WITH SOME HIGH
CLOUDS AND WARM TEMPERATURES REACHING THE 60S AND 70S. THE
APPROACH OF THE NEXT WEATHER SYSTEM WILL BRING ENOUGH
INSTABILITY TODAY FOR SOME SHOWER ACTIVITY ALONG THE HIGHER
REACHES OF THE ABSAROKAS AND BIGHORNS. WHILE MOISTURE HAS
STARTED TO INCREASE ACROSS NORTHERN WY IN THE PAST 24 HOURS,
THERE STILL ISN'T A WHOLE LOT TO PRODUCE MUCH ACCUMULATION WITH
SHOWERS TODAY.
THE MAIN SYSTEM ITSELF WILL BEGIN TO IMPACT WYOMING MONDAY
MORNING, AS A FRONT SWEEPS IN FROM THE NORTH. THE FIRST PUSH
SHOULD REACH THE NORTHERN WY/MT BORDER RIGHT AROUND SUNRISE
MONDAY, AND REACHES AROUND THE CONTINENTAL DIVIDE BY 18Z, BEFORE
SPREADING SOUTHWEST LATE IN THE AFTERNOON. THE FRONT WILL BRING
ALONG VALLEY RAIN AND MOUNTAIN SNOW BEHIND IT, SPREADING
SOUTHWARD THROUGH THE DAY. MOST AREAS SHOULD RECEIVE A GOOD
WETTING RAIN, BUT SOME SHADOWING ACROSS THE BIGHORN BASIN MAY
KEEP AMOUNTS THERE TO A MINIMUM. WITH THE FRONT STRETCHED ALONG
THE SOUTHERN WY BORDER DURING THE EVENING, BEST OPPORTUNITY FOR
RAINFALL WOULD BE FOCUSED FROM THE WINDS EAST ALONG THE GREENS
AND CASPER MOUNTAIN. RAIN DECREASES LATE MONDAY NIGHT INTO
TUESDAY, BUT A BRIEF SECONDARY NORTH WIND PUSH WILL KEEP VERY
LIGHT RAIN/SNOW GOING FOR ALL EXCEPT FOR THE BIGHORN BASIN AND
THE NW PARKS DURING THE DAY TUESDAY. CURRENT ACCUMULATION
NUMBERS HAVE REMAINED STEADY FOR A COUPLE TENTHS FOR THE
SOUTHERN 2/3 OF THE STATE, WITH THE HIGHEST BAND NEAR A HALF
INCH FOR THE WINDS EAST TO CASPER MOUNTAIN. MODELS HAVE NUDGED
AMOUNTS DOWNWARD SLIGHTLY SINCE YESTERDAY, AND WITH LAST COUPLE
EVENTS THE MODELS HAVE OVERESTIMATED FINAL TOTALS, SO CURRENT
TOTALS MAY BE A BIT HIGH.
ONCE THIS SYSTEM SWEEPS SOUTHEAST EARLY WEDNESDAY, UPPER LEVEL
PATTERN REMAINS FROM THE NORTHWEST, SO WHILE TEMPERATURES WILL
RETURN TO THE 60S AND 70S, WEAK EMBEDDED IMPULSES MAY BRING
LIGHT HEATING-OF-THE-DAY SHOWERS TO THE NORTHERN MOUNTAIN
THROUGH THE REST OF THE WEEK.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1105 AM MDT SUN MAY 3 2026
MAINLY VFR CONDITIONS THROUGH THE PERIOD. SOME LIGHT SHOWERS WILL BE
AROUND THE ABSAROKA MOUNTAINS NEAR KCOD THIS AFTERNOON, WITH A 20 TO
30 PERCENT CHANCE A SHOWER MOVES OVER KCOD DURING THE AFTERNOON. THE
ENTIRE AREA WILL SEE VERY LIGHT SHOWERS, OR MORE LIKELY VIRGA
SHOWERS, BETWEEN 18Z AND 00Z, WITH THE LAST DIMINISHING BY 03Z. ANY
SITE COULD SEE A GUSTY OUTFLOW WIND UP TO 50 KNOTS (HIGH END) FROM
THESE, THOUGH UP TO 30 KNOTS WOULD BE MOST LIKELY.
TONIGHT, A COLD FRONT MOVES IN FROM THE NORTH STARTING AROUND 12Z.
THIS BRINGS A GUSTY NORTH WIND SHIFT TO LOCATIONS EAST OF THE
CONTINENTAL DIVIDE, WITH THE STRONGEST WINDS AT KCOD AND KWRL.
PRECIPITATION THEN FOLLOWS, THOUGH THE BEST CHANCES HOLD OFF UNTIL
JUST AFTER THE PERIOD, FOR MONDAY AFTERNOON.
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.
UPDATE...ROWE
DISCUSSION...STRAUB
AVIATION...WITTMANN
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