817
FXUS65 KRIW 171127
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
527 AM MDT FRI APR 17 2026
KEY MESSAGES
- STEADY SNOW ENDS THIS MORNING. OTHERWISE, RATHER COOL TODAY
WITH A SCATTERING OF SNOW SHOWERS, ESPECIALLY IN THE
AFTERNOON.
- QUITE COLD TONIGHT WITH A HARD FREEZE FOR MOST LOCATIONS EAST
OF THE DIVIDE.
- DRY AND TRANQUIL WEATHER EXPECTED FROM SATURDAY THROUGH EARLY
NEXT WEEK, WITH ABOVE NORMAL TEMPERATURES RETURNING SUNDAY AND
ESPECIALLY FROM MONDAY THROUGH WEDNESDAY.
DISCUSSION
ISSUED AT 135 AM MDT FRI APR 17 2026
SCORE ONE FOR THE GFS YESTERDAY. IT HAD THE AREA OF SNOW FROM THE
FREMONT / NATRONA COUNTY LINE TO CASPER NAILED DOWN FAIRLY WELL.
SOME SNOW IS CONTINUING THIS MORNING AS I WRITE THIS AROUND 1 AM AND
WILL CONTINUE IN EASTERN PORTIONS OF THE AREA THROUGH THE NIGHT BUT
IT APPEARS THE HEAVIEST SNOW HAS COME TO AN END. WE WILL LIKELY
EXPIRE MOST OF THE ADVISORIES AT 6 AM AND LIKELY CANCEL THE WIND
RIVER RANGE AS MOST GUIDANCE SHOWS THE HEAVY SNOW JUST ABOUT OVER.
WE WILL LEAVE NATRONA COUNTY UP FOR NOW, GIVEN IT HAS BEEN THE
CENTER OF THE HEAVIEST SNOW AND ROADS SHOULD REMAIN SLICK UNTIL THE
STRONG MID APRIL SUN CAN MELT THEM OFF THROUGH THE MORNING.
THE MAIN STORY TODAY WILL BE THE MUCH COLDER TEMPERATURES WHEN
COMPARED THE PREVIOUS SEVERAL DAYS. WITH AREAS THAT SAW SNOW, LIKE
CASPER, STRUGGLING TO GET OUT OF THE 30S. AND, WITH MOIST NORTHWEST
FLOW REMAINING AS WELL AS CYCLONIC CURVATURE OVER THE AREA, THERE
WILL BE SOME CONVECTIVE SNOW SHOWERS AROUND THE AREA AND POSSIBLY A
FEW SNOW BANDS. THESE ARE ALMOST IMPOSSIBLE TO PINPOINT BUT MOST
AREAS WILL HAVE AT LEAST A 1 IN 5 CHANCE OF ONE. ACCUMULATIONS
SHOULD REMAIN LIGHT, WITH A LESS THAN 1 IN 10 CHANCE OF 3 INCHES OR
MORE EVEN IN THE MOUNTAINS, WITH MOST LOCATIONS RECEIVING LESS THAN
AN INCH. AT THIS TIME, TRAVEL CONCERNS FROM THEM SHOULD BE MINIMAL,
AS THE STRONG SUN ANGLE SHOULD KEEP ROADS MAINLY WET UNLESS THE SNOW
PERSISTS.
THESE SNOW SHOWERS SHOULD DECREASE AS WE LOSE THE HEATING OF THE
DAY, WITH MOST ENDING BY MIDNIGHT. THE CONCERN THEN TURNS TO THE
COLD TEMPERATURES. WE STILL LOOK TO HAVE A WIDESPREAD FREEZE ACROSS
MANY LOCATIONS EAST OF THE DIVIDE. WE WILL CONTINUE THE FREEZE
WARNINGS IN THE ZONES THAT ALREADY HAVE THEM. WE WILL LIKELY NEED
THEM IN OTHER ZONES BUT WILL LET THE DAY SHIFT DO THAT AFTER THE
WINTER WEATHER ADVISORIES ARE OVER. EXPECTED LOW TEMPERATURES HAVE
COME UP A BIT IN THE AREA WITH LITTLE SNOW, BUT MOST LOCATIONS STILL
HAVE A GREATER THAN 4 OUT OF 5 CHANCE OF LOW TEMPERATURES BELOW 25
DEGREES. EXACTLY HOW COLD IT DOES GET WILL HAVE TO DO WITH HOW
QUICKLY THE SKY CAN CLEAR, AND THERE IS STILL SOME UNCERTAINTY WITH
THIS.
MORE TRANQUIL WEATHER SHOULD THEN BE THE RULE FOR AT LEAST THE NEXT
4 DAYS AS RIDGING BUILDS ACROSS THE NORTHERN ROCKIES. TEMPERATURES
WILL BEGIN TO REBOUND. SATURDAY LOOKS NEAR TO BELOW NORMAL, BUT THEN
MUCH WARMER TEMPERATURES MOVE IN FOR SUNDAY AND THROUGH AT LEAST
WEDNESDAY. MONDAY AND TUESDAY LOOK ESPECIALLY WARM, WITH SOME OF THE
WARMER SPOTS MAKING A RUN AT 80 DEGREE HIGH TEMPERATURES. THE ONLY
CONCERN WOULD BE POSSIBLE ELEVATED FIRE WEATHER, ESPECIALLY IN AREAS
FAVORED TO SOUTHWESTERLY BREEZES, LIKE CASPER. SATURDAY LIKELY WON'T
BE A PROBLEM WITH THE SNOW BRINGING SOME NEEDED MOISTURE, BUT
POSSIBLE SUNDAY AND EARLY INTO NEXT WEEK, ESPECIALLY WEDNESDAY. THE
NEXT POTENTIAL WEATHER MAKER IS AN UPPER LEVEL LOW THAT WILL MOVE
INTO THE PACIFIC NORTHWEST ON TUESDAY AND MOVE TOWARD THE AREA FOR
THE MIDDLE OF THE WEEK. THERE HAS BEEN POOR MODEL CONSISTENCY IN
REGARDING THE LOW, SO DETAILS ARE IMPOSSIBLE TO PREDICT AT THIS
TIME. HOWEVER, THIS LOOKS TO BE OUR NEXT CHANCE OF PRECIPITATION FOR
THE MIDDLE OR END OF NEXT WEEK.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 524 AM MDT FRI APR 17 2026
WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS TERMINALS.
THE AREA IS NOW ON THE BACKSIDE OF THE SYSTEM THAT BROUGHT
THURSDAY'S PRECIPITATION. LIGHT SNOW IS EXPECTED TO COME TO AN END
THIS MORNING, WITH VFR CONDITIONS EXPECTED TO PREVAIL AT TERMINALS.
HOWEVER, SNOW SHOWERS WILL DEVELOP THIS AFTERNOON AS UNSTABLE
NORTHWEST FLOW SETS IN BEHIND THE TROUGH AXIS. KJAC WILL HAVE THE
BEST CHANCE OF DIRECT TERMINAL IMPACTS, AND AN MVFR PRO30 GROUP IS
INCLUDED THERE THROUGH THE AFTERNOON. KBPI, KPNA, AND KRKS WILL HAVE
LESSER CHANCES OF PRECIPITATION IMPACTS THOUGH WILL SEE AN INCREASED
WIND WITH GUSTS OF 25 TO 30 KNOTS THROUGH MUCH OF THE DAY.
EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL TERMINALS.
THE AREA IS NOW ON THE BACKSIDE OF THE SYSTEM THAT BROUGHT
THURSDAY'S PRECIPITATION. KCPR WILL HOLD ON TO PREVAILING MVFR TO
IFR IMPACTS THROUGH MID-MORNING AS SNOW CONTINUES. KLND WILL ALSO
HAVE A CHANCE FOR SNOW AND IFR IMPACTS THIS MORNING THOUGH WILL KEEP
THIS AS A TEMPO GROUP. SNOW SHOWERS ARE THEN EXPECTED TO DEVELOP
THIS AFTERNOON AS UNSTABLE NORTHWEST FLOW SETS IN BEHIND THE TROUGH
AXIS. ALL TERMINALS WILL HAVE A CHANCE AT SEEING AT LEAST BRIEF MVFR
IMPACTS THIS AFTERNOON, THOUGH CONFIDENCE IS GENERALLY LOW ON TIMING
AND EXACT PLACEMENT OF THIS ACTIVITY. SHOWERS WILL MOSTLY END BY
LATE EVENING, WITH CLEARING SKIES EXPECTED TOWARD 12Z SATURDAY.
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
WINTER STORM WARNING UNTIL 6 AM MDT EARLY THIS MORNING FOR
WYZ001-002-012.
FREEZE WARNING UNTIL 9 AM MDT SATURDAY FOR WYZ003>006-017-018.
WINTER WEATHER ADVISORY UNTIL 6 AM MDT EARLY THIS MORNING FOR
WYZ008>011.
WINTER STORM WARNING UNTIL 6 PM MDT THIS EVENING FOR WYZ014-
015.
WINTER WEATHER ADVISORY UNTIL NOON MDT TODAY FOR WYZ019-020-
022.
DISCUSSION...HATTINGS
AVIATION...MYERS
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