961
FXUS65 KRIW 022221
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
421 PM MDT FRI MAY 2 2025
KEY MESSAGES
- WARM AND DRY CONDITIONS TODAY THROUGH SATURDAY, WITH TEMPERATURES
PEAKING 15 TO 20 DEGREES ABOVE NORMAL.
- A SYSTEM WILL BEGIN TO PUSH INTO THE AREA SUNDAY, RETURNING
RAIN SHOWERS TO WESTERN WYOMING SUNDAY AFTERNOON.
- WIDESPREAD RAIN AND MOUNTAIN SNOW IS EXPECTED MONDAY AND
TUESDAY, ESPECIALLY ACROSS CENTRAL AND SOUTHERN WYOMING.
UPDATE
ISSUED AT 135 PM MDT FRI MAY 2 2025
A LOVELY DAY ACROSS WYOMING TODAY, WITH MILD TEMPERATURES AND
ONLY HIGH CLOUDS RACING IN FROM THE NORTH. NO CHANGES TO THE
ONGOING FORECAST, AS HIGH PRESSURE HOLDS OVER THE WEEKEND, WITH
HIGHS IN THE 70S.
NEXT STORM SYSTEM STILL TIMED TO START SUNDAY AFTERNOON, WITH
MORE WIDESPREAD RAIN MONDAY INTO TUESDAY. THE MAIN FOCUS OF
PRECIP WOULD BE OVERNIGHT MONDAY NIGHT ACROSS CENTRAL WYOMING.
ACCUMULATIONS AROUND A HALF INCH FOR LOWER ELEVATIONS, WHILE
NORTH FACING SLOPES OF THE WIND RIVER MOUNTAINS AND CASPER
MOUNTAIN LOOKING MORE LIKELY TO REACH ABOVE 1 INCH LIQUID
THROUGH THE END OF TUESDAY.
DISCUSSION
ISSUED AT 437 AM MDT FRI MAY 2 2025
A STRENGTHENING RIDGE WILL BE THE DOMINANT WEATHER FEATURE FOR THE
NEXT COUPLE OF DAYS AS IT BUILDS IN FROM THE WEST. MOSTLY CLEAR
SKIES ARE EXPECTED TODAY, WITH TEMPERATURES PEAKING ABOUT 5 DEGREES
ABOVE NORMAL FOR MOST LOCATIONS. WIND WILL REMAIN FAIRLY CALM,
MAKING FOR A PLEASANT WEATHER DAY ACROSS THE AREA. THIS TREND
CONTINUES ON SATURDAY AS THE RIDGE REACHES ITS MAXIMUM EXTENT OVER
WYOMING; 700MB TEMPERATURES WILL RISE TO NEAR 10C, HELPING HIGHS
PEAK 15 TO 20 DEGREES ABOVE NORMAL. HUMIDITY WILL DROP INTO THE
TEENS BOTH TODAY AND SATURDAY ACROSS LOWER ELEVATIONS, THOUGH
RELATIVELY LIGHT WIND SHOULD HELP TO MITIGATE FIRE WEATHER CONCERNS
DURING THIS PERIOD.
BY SUNDAY THE RIDGE WILL BEGIN TO BREAK DOWN AS A LONGWAVE TROUGH
MOVES ONTO THE WEST COAST AND AN ASSOCIATED 500MB LOW DEEPENS ACROSS
SOUTHERN CALIFORNIA. THIS WILL RETURN PRECIPITATION CHANCES WEST OF
THE CONTINENTAL DIVIDE, THOUGH THE MAJORITY OF THE AREA IS EXPECTED
TO SEE ANOTHER WARM AND DRY DAY. IT WILL BE BREEZIER AHEAD OF THE
APPROACHING SYSTEM, WHICH MAY LEAD TO AN INCREASING FIRE WEATHER
CONCERN FOR SOUTHERN AND CENTRAL WYOMING.
THE LOW WILL DRIFT NORTHEASTERLY ON MONDAY, SENDING A SURGE OF
MOISTURE TO THE ROCKIES. THIS WILL SPREAD RAIN AND MOUNTAIN SNOW
WIDELY ACROSS THE AREA THROUGH TUESDAY. THERE IS STILL SOME
INCONSISTENCY ON WHERE THE LOW WILL SET UP AS IT APPROACHES WYOMING
WHICH WILL HAVE AN IMPACT ON HOW MUCH MOISTURE IS REALIZED.
REGARDLESS, THE GENERAL TRACK OF THE LOW TO OUR SOUTH SHOULD LEAD TO
A RESPECTABLE PRECIPITATION EVENT FOR MUCH OF THE AREA, ESPECIALLY
ACROSS CENTRAL WYOMING WHERE AN UPSLOPING, NORTHEASTERLY FLOW
DEVELOPS. CURRENTLY, FORECAST PRECIPITABLE WATER VALUES ARE OVER
0.60" FOR MUCH OF THE AREA. THIS IS NEAR THE CLIMATOLOGICAL MAXIMUM
FOR THIS TIME OF YEAR AT KRIW (SPC SOUNDING CLIMATOLOGY). FOR
CONTEXT, THIS VALUE IS ONLY RIGHT AROUND THE MEAN DAILY PRECIPITABLE
WATER VALUES SEEN IN JULY. WITH TEMPERATURES EXPECTED TO REMAIN ON
THE WARMER SIDE, SNOW WILL BE LIMITED TO THE MOUNTAINS, WITH THE
MOST ALONG THE EASTERN SLOPES OF THE WIND RIVER RANGE. GIVEN THE
WARM WEEKEND FOLLOWED BY A DECENT RAIN EVENT, RIVER FLOOD POTENTIAL
MAY BE ELEVATED EARLY NEXT WEEK.
FURTHER AHEAD, ENSEMBLE CLUSTER GUIDANCE INDICATES A QUICK RETURN TO
RISING 500MB HEIGHTS BY WEDNESDAY. THIS FAVORS WARMER AND DRIER
CONDITIONS THROUGH THE END OF NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 415 PM MDT FRI MAY 2 2025
VFR CONDITIONS PREVAIL OVERNIGHT, WITH A CLEAR SKY AND LIGHT WINDS.
SIMILAR CONDITIONS CONTINUE INTO SATURDAY, WITH NO PRECIPITATION
EXPECTED.
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.
UPDATE...STRAUB
DISCUSSION...MYERS
AVIATION...WITTMANN/LAVOIE
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