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FXUS65 KRIW 081746
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
ISSUED BY NATIONAL WEATHER SERVICE BILLINGS MT
1146 AM MDT THU MAY 8 2025
KEY MESSAGES
- WARMING TREND CONTINUES TODAY WITH HIGHS WELL INTO THE 70S.
- VERY WARM TEMPERATURES CONTINUE THROUGH THE WEEKEND.
- TROUGH OF LOW PRESSURE SWEEPS IN LATE WEEKEND, INCREASING RAIN
CHANCES INTO THE FIRST HALF OF NEXT WEEK.
DISCUSSION
ISSUED AT 109 AM MDT THU MAY 8 2025
THE LATEST RETURN OF SPRING CONTINUES TO BUILD ACROSS WESTERN WY
THE NEXT FEW DAYS AS H5 RIDGING BUILDS ACROSS THE INTERMOUNTAIN
WEST. H7 TEMPERATURES RANGING 5 TO 10C WILL TRANSLATE TO SFC
TEMPS IN THE 70S ACROSS THE LOWER ELEVATIONS TODAY. SINCE THE
RIDGE HASN'T YET BUILD INTO WYOMING, A WEAK SHORTWAVE WILL SWEEP
GENERALLY ACROSS NORTHWEST WY DURING THE AFTERNOON HOURS. THIS
WAVE WILL TAP SOME OF THE DAYTIME HEATING, ALLOWING SOME SHOWER
ACTIVITY TO BUILD ALONG THE HIGHEST MOUNTAIN RANGES DURING PEAK
HEATING. MOST OF THESE WILL BE SMALLER IN SIZE, SO ANY
ACCUMULATIONS WILL BE MINOR.
RIDGING BUILDS CLOSER TO WESTERN WY ON FRIDAY, BUT TEMPERATURES
WILL REMAIN SIMILAR TO THURSDAY MAINLY IN THE 70S. SIMILAR TO
TODAY, A WEAK WAVE WILL SWEEP AROUND THE EDGE OF THE RIDGE
DURING THE AFTERNOON. WITH THE RIDGE CLOSER TO WESTERN WY, IT
WILL SUPPRESS CONVECTION FOR MOST AREAS DURING PEAK HEATING, BUT
THE BIGHORNS AND AREAS DOWNWIND ACROSS JOHNSON AND NATRONA
COUNTIES WILL BE FAR ENOUGH FROM THE RIDGE TO ALLOW SOME
SHOWERS TO AGAIN BUBBLE UP DURING PEAK HEATING.
OVER THE WEEKEND, THE RIDGE FINALLY CENTERS ON WESTERN WY,
DEFLECTING ANY IMPULSES OFF TO THE NORTH. H7 TEMPERATURES JUMP
TO 10 TO 15C, SO TEMPERATURES IN THE UPPER 70S AND LOWER 80S
ARE LIKELY. SOME AREAS OF THE BIGHORN BASIN AND JOHNSON COUNTY
MAY JUMP INTO THE UPPER 80S, WITH A REMOTE 90 DEGREE READING NOT
OUT OF THE QUESTION. THIS RIDGING AND WARM TEMPERATURES ALOFT
WILL INCREASE THE THREAT FOR SNOWMELT OF THE REMAINING HIGHER
ELEVATION SNOWPACK.
EARLY NEXT WEEK FOCUSES ON THE NEXT LARGE-SCALE TROUGH COMING
ASHORE ALONG THE PACNW. LATEST MODEL RUNS SHOWING SOME IMPROVED
TAP OF MOISTURE OFF THE PACIFIC INTO WESTERN WY. MODELS ARE
STILL DIFFERING ON THE DEPTH AND SPEED OF THIS NEXT TROUGH, BUT
ARE STARTING TO INCREASE SOME OF THE RAIN CHANCES OUT WEST DUE
TO THE IMPROVED MOISTURE AVAILABILITY.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1144 AM MDT THU MAY 8 2025
VFR FLIGHT CONDITIONS ARE ANTICIPATED THIS TAF PERIOD AT ALL
TERMINALS AS HIGH PRESSURE DOMINATES THE REGION. THERE IS A 30%
CHANCE IN SHOWERS AND A FEW RUMBLES OF THUNDER AT KCOD BETWEEN
21Z-02Z. HOWEVER, BECAUSE OF THE UNCERTAINTY IN DIRECT IMPACTS
AT KCOD, WENT WITH A PROB30 AT THIS TIME. A STRAY ISOLATED
SHOWER CANNOT BE RULED OUT BETWEEN 22Z-05Z AT KRIW, KCPR, KLND,
AND KWRL BUT CHANCES (AROUND 15%) ARE TOO LOW TO INCLUDE IN TAF
AT THIS TIME. SHOULD A SHOWER DIRECTLY IMPACT A TERMINAL OR BE
IN THE VICINITY, BRIEF GUSTS UP AROUND 15-20KTS CANNOT BE RULED
OUT.
EXPECT WINDS TO INCREASE THIS AFTERNOON WITH GUSTS AROUND 20KTS AT
KRKS, KPNA, AND KBPI. OTHERWISE, WINDS SHOULD GENERALLY BE AROUND OR
LESS THAN 10KTS AT ALL OTHER TERMINALS.
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...STRAUB
AVIATION...GERHARDT
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