079 
FXUS65 KRIW 230323
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
923 PM MDT FRI MAR 22 2013

.UPDATE...
ISSUED AT 922 PM MDT FRI MAR 22 2013

PREVIOUS FORECAST IN GOOD SHAPE. BEST SNOW THIS EVENING FELL NEAR
AND ALONG THE LANDER FOOTHILLS AND PARTS OF THE EAST SLOPES OF THE
WIND RIVER MOUNTAINS. WILL KEEP HIGHER POPS THERE FOR THE REST OF 
TONIGHT...BUT SLIGHTLY DECREASE ELSEWHERE. PARTS OF FAR WEST COULD 
EVEN CLEAR TOWARDS MORNING WITH QUITE COLD TEMPERATURES. IT WILL BE
WARMER EAST OF THE DIVIDE WHERE CLOUD COVER WILL REMAIN TONIGHT.

&&

.SHORT TERM...TONIGHT THROUGH SATURDAY

COLD MOIST UNSTABLE NORTHWEST FLOW WILL BRING PERIODS OF SNOW SHOWERS
THROUGH SATURDAY. TEMPERATURES WILL BE WINTER LIKE. BRIEF MODERATE TO
HEAVY SNOWFALLS CAN BE EXPECTED WITH LOCAL ACCUMULATIONS OF 3 TO 5
INCHES WHICH SHOULD MELT RAPIDLY IN THE LOWER ELEVATIONS. 

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

THE TROUGH WHICH IS EXPECTED TO BRING SOME SNOWFALL ACROSS THE ARE
ON SATURDAY WILL BEGIN TO MOVE FURTHER EAST OF THE CWA SATURDAY
NIGHT...WITH SHOWER COVERAGE WEAKENING ACROSS THE AREA. A QUICK
SHOT OF WRAP AROUND SHOWER ACTIVITY WILL BE POSSIBLE LATE SUNDAY
AFTERNOON BEFORE THE CORE OF LOW PRESSURE MOVES OFF INTO THE
CENTRAL AND NORTHERN PLAINS. 

THE DEPARTURE OF THIS SYSTEM WILL ALLOW NORTHWEST FLOW TO RETURN TO
THE AREA BY MONDAY AFTERNOON...AS AN AREA OF HIGH PRESSURE
APPROACHES THE STATE. RELATIVELY DRY AND WARMING CONDITIONS NOTED
THROUGH TUESDAY MORNING UNDER THE PRESENCE OF THIS HIGH PRESSURE.
A SERIES OF DISTURBANCES IN THE RIDGE WILL IMPACT NORTHWEST
WYOMING BRINGING OCCASIONAL LIGHT SHOWERS OVER THE NORTHWEST
MOUNTAINS THROUGH LATE WEDNESDAY NIGHT.

AN APPROACHING AREA OF LOW PRESSURE WILL MOVE DOWN THE COAST OF
THE PACIFIC NORTHWEST...SENDING ADDITIONAL SHOWER ACTIVITY
THROUGH THE AREA. MEANWHILE...THE AXIS OF THE HIGH PRESSURE WILL
MOVE THROUGH THE AREA BY FRIDAY EVENING...ALLOWING SOUTHWEST FLOW
TO BE FOUND ACROSS THE AREA. ANOTHER AREA OF LOW PRESSURE WILL
BEGIN TO MOVE INLAND OVER SOUTHERN CALIFORNIA ON FRIDAY. WITH THE
ANTICIPATED SOUTHWEST FLOW...THIS SYSTEM WILL BRING SHOWER
ACTIVITY ACROSS MUCH OF THE AREA WEST OF THE DIVIDE BY LATE FRIDAY
NIGHT.

&&

.AVIATION.../00Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...SNOW SHOWERS WILL OCCUR OVER THE
MOUNTAINS THROUGH 18Z SATURDAY WITH MVFR TO IFR CONDITIONS
PREVAILING. IN THE WESTERN VALLEYS SCATTERED SNOW SHOWERS WILL
OCCUR THROUGH 12Z SATURDAY WITH LESS SNOW SHOWERS AFTER 12Z SATURDAY.
EXPECT BRIEF MVFR TO IFR CONDITIONS TO OCCUR AT TIMES AT KJAC...KAFO...
KEMM...KBPI...KPNA AND KRKS. EXPECT RAPID CHANGES IN CONDITIONS
AT TERMINAL SITES THAT ARE IMPACTED BY SNOW SHOWERS. VFR CONDITIONS
WILL BECOME PREVALENT AFTER 18Z SATURDAY WITH LOCAL IFR/MVFR 
CONDITIONS LINGERING OVER THE MOUNTAINS. 

EAST OF THE CONTINENTAL DIVIDE...SNOW SHOWERS WILL BE WIDESPREAD 
THROUGH 00Z SUNDAY. MOUNTAINS WILL BE OBSCURED IN IFR CEILINGS
AND VISIBILITIES WITH PERIODS OF HEAVY SNOW SHOWERS. IN THE LOWER
ELEVATIONS AREAS OF MVFR TO IFR CEILINGS AND VISIBILITIES IN
MODERATE TO LOCALLY HEAVY SNOW SHOWERS WILL OCCUR...INCLUDING
KBYG...KCOD...KCPR...KDUB...KGEY...KLND...KPOY...KRIW AND KTHP.
EXPECT CONDITIONS TO CHANGE RAPIDLY AT TERMINAL SITES THAT ARE
IMPACTED BY SNOW SHOWERS.

&&

.FIRE WEATHER...

COLD MOIST UNSTABLE NORTHWEST FLOW WILL BRING PERIODS OF SNOW SHOWERS
THROUGH SUNDAY. TEMPERATURES WILL BE WINTER LIKE WITH HIGH
HUMIDITY AND LOW MIXING HEIGHTS WITH GENERALLY POOR SMOKE
DISPERSAL THROUGH THE WEEKEND. CLEARING WILL OCCUR ON MONDAY.

&&

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

$$

UPDATE...KPL
SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER