116
FXUS65 KRIW 280351
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
951 PM MDT THU MAR 27 2025
KEY MESSAGES
- TEMPERATURES CONTINUE TO WARM ABOVE NORMAL THIS AFTERNOON WITH
HIGHS NEARING ALL TIME MARCH RECORDS.
- CRITICAL FIRE WEATHER CONDITIONS CONTINUE ALONG THE I-25
CORRIDOR THIS AFTERNOON, WITH THE COMBINATION OF WIND GUSTS UP
TO 25 TO 35 MPH, LOW RELATIVE HUMIDITY VALUES (10-20%), AND
ABOVE NORMAL TEMPERATURES.
- A WEATHER SYSTEM TONIGHT WILL BRING MORE SEASONABLE
TEMPERATURES AND PRECIPITATION FRIDAY THROUGH THE WEEKEND.
THESE SEASONABLE TEMPERATURES AND PRECIPITATION CHANCES ARE
FORECAST TO CONTINUE INTO NEXT WEEK.
UPDATE
ISSUED AT 211 PM MDT THU MAR 27 2025
SATELLITE IMAGERY (20Z) SHOWS A MOSTLY SUNNY SKY ACROSS MUCH OF
CENTRAL AND EASTERN WYOMING THAT IS ALLOWING FOR SUFFICIENT
INSOLATION ACROSS THE REGION. SUFFICIENT INSOLATION AND 700-MB
TEMPERATURES AROUND 7C HAVE TRANSLATED TO TEMPERATURES IN THE MID-
70S AND THESE TEMPERATURES WILL CONTINUE TO RISE WELL ABOVE NORMAL
THIS AFTERNOON, WITH MULTIPLE RECORD HIGHS IN JEOPARDY. AS OF
20Z, SURFACE OBSERVATIONS ARE SHOWING RELATIVE HUMIDITY VALUES
LESS THAN 15% WITH SOUTHWEST WIND GUSTS AROUND 25 MPH AT MANY
LOCATIONS EAST OF THE DIVIDE. THESE DRY CONDITIONS, GUSTY WINDS,
AND WARM TEMPERATURES CONTINUES TO CAUSE ELEVATED TO CRITICAL
FIRE WEATHER CONDITIONS INTO THE EVENING.
A COLD FRONT REMAINS ON TRACK TO IMPACT THE REGION TONIGHT AND BRING
AN END TO THE ABOVE NORMAL WARMTH AND DRY WEATHER. LOCATIONS ACROSS
WESTERN AND NORTHWESTERN WYOMING HAVE THE GREATEST CHANCE (80-90%)
AT SEEING PRECIPITATION WITH THE COLD FRONT. PRECIPITATION IS
EXPECTED TO BEGIN AS RAIN BUT QUICKLY TRANSITION TO SNOW ACROSS
HIGHER ELEVATIONS AND A RAIN/SNOW MIX IN LOWER ELEVATIONS OF
WEST/NORTHWEST WYOMING. PRECIPITATION CHANCES DECREASE AS THE
FRONT PUSHES EAST EARLY FRIDAY MORNING. RAIN AND SNOW CHANCES
INCREASE AREAWIDE FRIDAY AFTERNOON AS A SHORTWAVE TRAVERSES THE
REGION.
DISCUSSION
ISSUED AT 131 AM MDT THU MAR 27 2025
HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE CWA TODAY, LEADING
TO ANOTHER DAY OF ABOVE NORMAL TEMPERATURES. RECORD HIGH
TEMPERATURES ARE STILL EXPECTED ACROSS MOST AREAS EAST OF THE
DIVIDE, WITH HIGHS RANGING FROM THE MIDDLE 70S TO NEAR 80 DEGREES.
ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS WILL RETURN ACROSS THE
WIND CORRIDOR THIS AFTERNOON (FROM ROCK SPRINGS TO CASPER) AS WELL,
WITH WIND GUSTS OF 25 TO 35 MPH OCCURRING OVER THIS AREA AS WELL AS
SOUTHERN LINCOLN AND SUBLETTE COUNTIES. MID TO HIGH LEVEL CLOUDS
WILL INCREASE OVER WESTERN PORTIONS THROUGH THE AFTERNOON, AS
MOISTURE FROM AN UPPER LOW OFF THE WEST COAST STREAMS OVER THE
REGION. THERE WILL BE ENOUGH MOISTURE FOR A CHANCE FOR RAIN SHOWERS
TO OCCUR (20% CHANCE) OVER NORTHWESTERN PORTIONS OF THE FORECAST
AREA. THERE IS A 1 IN 10 CHANCE FOR A RUMBLE OF THUNDER TO OCCUR
WITHIN THESE SHOWERS AS WELL. CHANCES FOR RAIN WILL INCREASE (60-
80%) OVER THESE AREAS THROUGH THE EVENING, AS A COLD FRONT
ASSOCIATED WITH THE UPPER LOW BEGINS TO MOVE OVER THE FORECAST AREA.
WINDS WILL INCREASE AGAIN AS THE FRONT PROGRESSES EASTWARD THROUGH
THE NIGHT, WITH BRIEF GUSTS OF 35 TO 45 MPH EXPECTED (ESPECIALLY IN
THE CENTRAL BASINS) AND EXITING FAR EASTERN PORTIONS OF THE FORECAST
AREA BY 12Z FRIDAY. AN ISOLATED SHOWER (20% CHANCE) COULD OCCUR IN
EASTERN PORTIONS OF THE BIGHORN BASIN WITH THE PASSAGE OF THE FRONT.
TEMPERATURES WILL BE 10 TO 15 DEGREES COOLER FRIDAY, AS A RESULT OF
THE FRONT, WITH HIGHS RETURNING TO THE 50S AND 60S. WINDS WILL NOT
BE AS STRONG EITHER. A SHORTWAVE TROUGH FROM THE UPPER LOW WILL
APPROACH THE REGION, BRINGING THE CHANCE FOR WIDELY SCATTERED
SHOWERS BACK TO THE CWA. THE BEST CHANCES (30-50%) LOOK TO BE OVER
FAR WESTERN PORTIONS AND THE WIND CORRIDOR. THERE COULD BE ENOUGH
INSTABILITY WITH THE SHOWERS OVER SWEETWATER COUNTY FOR A
THUNDERSTORM TO OCCUR. SHOWERS LOOK LIKELY (40-60%) ACROSS THE
FORECAST AREA FRIDAY NIGHT, AS THE SHORTWAVE MOVES TO THE EAST-
NORTHEAST THROUGH THE NIGHT. SNOW LEVELS LOOK TO RANGE BETWEEN 6000
AND 7000FT DURING THIS TIME.
PRECIPITATION CHANCES WILL CONTINUE TO BE WIDESPREAD ACROSS THE CWA
SATURDAY, AS THE UPPER LOW MOVES ONSHORE AND OVER THE PACNW,
WEAKENING AND FILLING AS IT PROGRESSES EASTWARD. THE BEST CHANCES
WILL OCCUR BY LATE AFTERNOON AND THROUGH SATURDAY NIGHT, AS THE MAIN
LOW MOVES OVER THE AREA. SNOW WILL BE POSSIBLE IN THE LOWER
ELEVATIONS DURING THIS TIME, WITH ACCUMULATIONS ONLY UP TO AN INCH
EXPECTED AT THIS TIME. 3 TO 6 INCHES ARE EXPECTED IN THE MOUNTAINS,
WITH LOCALLY HIGHER AMOUNTS OF 8 TO 12 INCHES IN THE BIGHORNS. THIS
WILL BE DUE TO A MORE FAVORABLE UPSLOPE COMPONENT TO OCCUR OVER THE
BIGHORNS AS THE LOW PASSES TO THE SOUTH.
PRECIPITATION WILL END FROM THE SOUTHWEST TO THE NORTHEAST THROUGH
THE DAY SUNDAY. A TRANSITORY RIDGE WILL BE IN PLACE BY MONDAY, AS A
ANOTHER UPPER LOW MAKES ITS WAY TO THE PACNW. THIS WILL KEEP
PACIFIC MOISTURE STREAMING OVER THE REGION AND COULD RESULT IN
ISOLATED RAIN SHOWERS OVER WESTERN AND SOUTHERN PORTIONS AND
SNOW IN THE WESTERN MOUNTAINS.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 951 PM MDT THU MAR 27 2025
VFR CONDITIONS PREVAIL FOR MOST THE PERIOD FOR MOST TERMINALS.
WITH THE COLD FRONT, EXPECT A 1 TO 4 HOUR PERIOD OF RAIN/SNOW
SHOWERS. MOST LIKELY CHANCES (3 OUT OF 5) FOR PREVAILING LIGHT
RAIN OR SNOW IS AT KJAC. SHOWERS ARE ALSO POSSIBLE AT KBPI AND
KPNA (2 OUT OF 5) AND KCOD AND KWRL (1 OUT OF 4) WITH THE
FRONT.
WINDS WILL BECOME WESTERLY TO NORTHWESTERLY, BUT RETURN TO
TYPICAL NIGHTTIME DRAINAGE FLOWS 2 TO 4 HOURS AFTER THE FRONTAL
PASSAGE. SOUTHWEST WINDS WILL INCREASE AGAIN FRIDAY LATE MORNING
AND EARLY AFTERNOON FOR MANY TERMINALS. THE NEXT SYSTEM WILL
BRING A CHANCE (AROUND 1 IN 3) OF SHOWERS AND LOWERED CEILINGS
AND POSSIBLE MVFR AND POSSIBLE IFR CONDITIONS ROUGHLY ALONG AND
EAST OF A KRKS TO KRIW TO KWRL LINE (ABOUT A 1 IN 3 CHANCE) AFTER
02Z SATURDAY.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC FOR
THE LATEST INFORMATION ON SMOKE, ICING, AND TURBULENCE
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...GERHARDT
DISCUSSION...LAVOIE
AVIATION...HATTINGS
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