Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 182049
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
249 PM MDT FRI APR 18 2014

.SHORT TERM...TONIGHT AND SATURDAY

STRONG COLD FRONT MOVING TO NEAR THE CONTINENTAL DIVIDE ATTM WITH
STRONG SW WINDS AHEAD OF IT AND COLDER RAIN AND SNOW SHOWERS BEHIND
IT. COLD ENOUGH IN THE STAR VALLEY FOR A QUICK CHANGEOVER TO SNOW
WITH UP TO A QUICK INCH REPORTED. JACKSON VALLEY STAYED RAIN WITH
RAINFALL AMOUNTS GENERALLY BETWEEN .15 AND .30 INCHES. WINDS ARE
SURFACING EAST OF THE DIVIDE IN MANY AREAS WITH WIND GUSTS OF 40 TO
50 MPH IN QUITE A FEW AREAS AND LOCALIZED GUSTS BETWEEN 55 AND 60
MPH. SOME AREAS WILL FLIRT WITH OR BRIEFLY TOUCH HIGH WIND THROUGH
00Z OR A LITTLE LATER IN THE CENTRAL ZONES. SPS IS COVERING THESE
AREAS. THERE WILL BE A FEW RAIN SHOWERS WITH FROPA EAST OF THE
DIVIDE BUT THEY WILL BE JUST ISOLATED IN MANY AREAS WITH THE DRY
AIRMASS AHEAD OF IT. THE NORTHERN ZONES HOWEVER...HAVE A LITTLE LOW
LEVEL MOISTURE TO WORK WITH SO A BETTER SHOT THERE ALONG WITH AN
ISOLATED THUNDERSTORM STILL POSSIBLE BUT NOT NECESSARILY LIKELY.
SECONDARY FRONT THAT DROPS DOWN BEHIND THE WEAKENING UPPER
LOW/SHORTWAVE TONIGHT WITH BOUNDARY LAYER MOISTENING UP QUITE A BIT
IN NATRONA COUNTY. COULD BE ENOUGH FOR LOW CLOUDS OR PATCHY FOG SO
INDICATED THIS IN THE FORECAST AROUND SUNRISE. AND WITH THE RECENT
RAIN AND SNOW OUT WEST...WILL ADD SOME LOW CLOUDS AND FOG TO THE
JACKSON AND STAR VALLEYS FOR LATER TONIGHT THROUGH 15Z SATURDAY. ON
SATURDAY...SOME CONVECTION IS POSSIBLE ACROSS SWEETWATER COUNTY AS
FRONT BOUNDARY STALLS OUT DOWN THERE AND THEN A LITTLE BIT OF
MOISTURE AND VERY WEAK FORCING IS PROVIDED FROM A SYSTEM WELL TO OUR
SOUTH. SCATTERED HIGHER TERRAIN SHOWERS ARE CERTAINLY A
POSSIBILITY...MORE ISOLATED ON THE RED DESERT FLOOR. TEMPERATURES
WILL NOT BE QUITE AS WARM TOMORROW EAST OF THE DIVIDE WHILE WEST OF
THE DIVIDE...THEY`LL ACTUALLY BE WARMER WITHOUT THE PCPN.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY NIGHT

THE REST OF THE WEEKEND INTO MONDAY REMAINS RELATIVELY QUIET...WITH
A WEAK COLD FRONT MOVING THROUGH THE AREA SUNDAY MORNING. ISOLATED
SHOWERS AND AN ISOLATED THUNDERSTORM WILL BE POSSIBLE ACROSS
SOUTHERN PORTIONS SUNDAY...WITH DRY CONDITIONS ON MONDAY.

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE NORTHERN ROCKIES INTO
ALBERTA MONDAY...AND SLOWLY PROGRESS EASTWARD INTO THE HIGH PLAINS
TUESDAY...AS THE NEXT STORM SYSTEM FROM THE NORTH PACIFIC DIGS
SOUTHEASTWARD INTO NORTHERN CALIFORNIA AND THE GREAT BASIN. A
DUMBBELL LOW WILL FORM BY 12Z WEDNESDAY AND PROGRESS EASTWARD OVER
MONTANA...BEFORE EJECTING INTO THE NORTHERN PLAINS BY 18Z THURSDAY.
NORTHWEST FLOW ALOFT WILL OCCUR IN THE STORMS WAKE...AS A RIDGE OF
HIGH PRESSURE BUILDS BACK INTO THE AREA ON FRIDAY INTO SATURDAY. THE
12Z GFS AND ECMWF HAVE COME MORE IN LINE WITH EACH OTHER THAN
PREVIOUS RUNS. THIS IS A PROMISING SIGN FIVE DAYS OUT...SO WILL
CONTINUE TO MONITOR ANY CHANGES AS THE STORM APPROACHES SHORE.

ON TUESDAY...ISOLATED TO SCATTERED RAIN AND SNOW SHOWERS WILL ENTER
WESTERN PORTIONS EARLY TUESDAY MORNING...INCREASING THROUGH THE DAY.
ISOLATED THUNDERSTORMS WILL BE POSSIBLE BY THE AFTERNOON ACROSS MOST
OF THE AREA...WITH MOST OF THE PRECIPITATION OCCURRING ACROSS
WESTERN...SOUTHWESTERN AND NORTHERN PORTIONS. SOUTHWEST FLOW ALOFT
WILL CREATE GUSTY WINDS DURING THE DAY AHEAD OF THE COLD FRONT
ACROSS CENTRAL AND SOUTHERN PORTIONS...AND PUSHING AFTERNOON
TEMPERATURES EAST OF THE DIVIDE INTO THE 70S AND POSSIBLY LOWER
80S.

ON WEDNESDAY...SNOW WILL FALL TUESDAY NIGHT INTO WEDNESDAY MORNING
ACROSS THE WESTERN MOUNTAINS AND THE HIGHER ELEVATIONS OF THE
BIGHORN MOUNTAINS. RAIN WILL SLOWLY CHANGE OVER TO SNOW ACROSS THE
WESTERN VALLEYS AND BASINS...BECOMING ALL SNOW SHORTLY BEFORE DAWN.
A RAIN/SNOW MIX WILL RETURN TO THESE AREAS BY LATE MORNING THROUGH
THE REST OF THE DAY. RAIN/SNOW SHOWERS WILL ALSO OCCUR ACROSS
SOUTHERN PORTIONS THROUGH MID MORNING BEFORE CHANGING OVER TO ALL
RAIN. THE REST OF THE AREA CAN EXPECT ISOLATED TO SCATTERED RAIN
SHOWERS THROUGH THE DAY.

ON THURSDAY...SNOW WILL CONTINUE ACROSS THE WEST...WITH A FEW
RAIN/SNOW SHOWERS MIXED IN LATER IN THE DAY. SNOW WILL FALL ACROSS
SOUTHERN PORTIONS...BECOMING MORE ISOLATED AND CHANGING TO RAIN BY
THE AFTERNOON. OVERALL...CHANCES FOR PRECIPITATION BECOME MORE
ISOLATED THROUGHOUT THE DAY.

BY FRIDAY...LINGERING ISOLATED SHOWERS ACROSS THE WEST.
OTHERWISE...COOLER AND DRY CONDITIONS.

&&

.AVIATION.../00Z ISSUANCE/

COLD FRONT WILL MOVE QUICKLY EAST OF THE DIVIDE THROUGH EVENING
HOURS WITH A LOT OF WIND AND A FEW SHOWERS AND EVEN AN ISOLATED
THUNDERSTORM POSSIBLE. SCATTERED MOUNTAIN OBSCURATION AND SNOW
SHOWERS WILL PERSIST OUT WEST INTO THE EVENING BEFORE RETREATING TO
THE HIGHER PEAKS. LOW CLOUDS AND PATCHY FOG MAY FORM IN THE JACKSON
AND STAR VALLEYS OVERNIGHT AFFECTING THE KJAC TERMINAL WITH MVFR
CONDITIONS. ANOTHER AREA OF LOW CLOUDS AND FOG MAY FORM OVER NATRONA
COUNTY BY LATER TONIGHT AFFECTING THE KCPR TERMINAL BY SUNRISE.
OTHERWISE...EXPECT VFR CONDITIONS IN MOST AREAS WITH WINDS
DECREASING LATER TONIGHT. ON SATURDAY...SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE EXPECTED IN THE FAR SOUTH INCLUDING KRKS.
OTHER AREAS WILL BE DRY WITH VFR CONDITIONS AND LESS WIND. STILL
BREEZY TO LOCALLY WINDY BUT NOT AS STRONG AS TODAY.

&&

.FIRE WEATHER...

A STRONG COLD FRONT WILL CONTINUE MOVING ACROSS CENTRAL WYOMING THIS
AFTERNOON WITH STRONG WEST TO SOUTHWEST WINDS OF 40 TO 50 MPH AND
ISOLATED TO WIDELY SCATTERED SHOWERS. THUNDERSTORMS...IF ANY...WILL
BE VERY ISOLATED AND MAINLY CONFINED TO THE NORTHEAST PART OF THE
DISTRICT. MOUNTAIN SNOW SHOWERS OUT WEST WILL DIMINISH AND RETREAT
TO THE HIGHER PEAKS WITH TIME TONIGHT. SATURDAY WILL NOT BE AS WINDY
BUT STILL BREEZY TO LOCALLY WINDY...ESPECIALLY THE MOUNTAIN AND
FOOTHILL AREAS. THERE WILL BE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS IN SWEETWATER COUNTY...ESPECIALLY SOUTH OF INTERSTATE
80 SATURDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...SKRBAC
LONG TERM...LAVOIE
AVIATION...SKRBAC
FIRE WEATHER...SKRBAC









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