Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 200446
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1046 PM MDT TUE MAY 19 2015

.SHORT TERM...TONIGHT THROUGH WEDNESDAY

ELONGATED UPPER LOW JUST TO OUR SOUTH STILL LOOKS LIKE IT WILL
WEAKEN BUT MOVE TOWARDS THE RED DESERT EARLY THIS EVENING AND THEN
MOVE EVER SO SLOWLY EWD TOWARDS CASPER MOUNTAIN BY 12Z WEDNESDAY. A
SECONDARY MID LEVEL CIRCULATION IS STILL EXPECTED TO MOVE INTO FAR
SWRN WYOMING BY THIS EVENING BEFORE WEAKENING AND SHIFTING BACK TO
THE WEST. WCB/UPGLIDE IN MOIST ELY FLOW WILL KEEP STEADY PCPN GOING
INTO THE EVENING HOURS WITH SOME MODERATE LOWER ELEVATION RAIN AT
TIMES AND HEAVY MOUNTAIN SNOW. AS THE LOW GRADUALLY WEAKENS AND
FILLS...THE WIDESPREAD PCPN WILL START TO WEAKEN AND RETREAT TO
MAINLY THE MOUNTAINS WITH SOME AREAS OF LIGHT RAIN STILL HOLDING ON
ACROSS SOME OF CENTRAL WYO. LOW CLOUDS AND FOG WILL BE AROUND BEHIND
THIS SYSTEM LATER TONIGHT THROUGH WEDNESDAY. AND THEN BY WEDNESDAY
AFTERNOON...THE NEXT SYSTEM IS ALREADY MOVING TOWARDS CA WITH
DEVELOPING DIFFLUENT FLOW AND APPROACHING JET FOR WRN WYO. DAYTIME
HEATING AND MOISTURE WILL LEAD TO PLENTY OF SHOWERS AND SOME
THUNDERSTORMS WITH SMALL HAIL OUT WEST WED AFTN. LOOKS GENERALLY DRY
EAST OF THE DIVIDE EXCEPT PERHAPS THE MOUNTAINS. SNOW LEVELS ARE
QUITE LOW RIGHT NOW BETWEEN 6K AND 7K AND MAY EVEN LOWER FURTHER
BRIEFLY AT TIMES TONIGHT.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

AFTER A BRIEF BREAK IN THE WEATHER WEDNESDAY NIGHT AND EARLY
THURSDAY...THE WET MAY PATTERN SHOULD CONTINUE THROUGH MOST OF THE
UPCOMING EXTENDED PERIOD. MEDIUM RANGE MODELS ARE IN PRETTY GOOD
AGREEMENT WITH RESPECT TO MID/UPPER LEVEL TROUGH OVER THE WESTERN
UNITED STATES THROUGH THE MEMORIAL DAY WEEKEND. LOOKS LIKE
PRECIPITATION CHANCES INCREASE AGAIN BY FRIDAY. WILL BETTER
PINPOINT PRECIPITATION AREAS AND AMOUNTS AS WE GET CLOSER TO THE
WEEKEND...BUT CONTINUITY SUGGESTS WET CONDITIONS WITH BELOW NORMAL
TEMPERATURES CONTINUING ACROSS WEST CENTRAL WYOMING.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

ALTHOUGH RAIN AND SNOW WILL CONTINUE TO QUICKLY DECREASE IN COVERAGE
LATE TONIGHT...MVFR AND SOME IFR CEILINGS WILL CONTINUE OVER MUCH OF
THE AREA THROUGH WEDNESDAY MORNING. THERE COULD ALSO BE SOME FOG DUE
TO THE RECENT PLETHORA OF MOISTURE...BUT EXTENSIVE LOW CLOUDS SHOULD
KEEP FOG FROM BECOMING TOO WIDESPREAD. LOW CEILINGS ARE EXPECTED TO
LIFT TO VFR OR EVEN SCATTER OUT BETWEEN 18Z-21Z WEDNESDAY. EXCEPT
FOR SOME SNOW SHOWERS OVER THE MOUNTAINS WEDNESDAY AFTERNOON...DRY
CONDITIONS ARE EXPECTED. WEDNESDAY NIGHT...FOG AND LOW CLOUDS COULD
REDEVELOP OR ADVECT FROM THE EAST. THE BEST SHOT AT LOW CLOUDS OR
FOG WILL BE AT THE KCPR AIRPORT WITH THE MOIST EASTERLY FLOW
COMBINED WITH RECENT MOISTURE. MOUNTAINS WILL BE OBSCURED IN MUCH OF
THE AREA THIS MORNING.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

AREAS WITH MVFR CEILINGS ARE EXPECTED THROUGH WEDNESDAY
MORNING...WITH SOME MOUNTAIN SNOW/VALLEY RAIN. ALSO...SOME FOG COULD
ALSO OCCUR WEDNESDAY MORNING. FOG AND LOW CLOUDS ARE EXPECTED TO
LIFT TO VFR CONDITIONS BY AROUND 18Z WEDNESDAY. SCATTERED MOUNTAIN
SNOW/VALLEY RAIN SHOWERS WITH A FEW THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON...WITH BRIEF MVFR/IFR CONDITIONS. THE BEST...ALTHOUGH WEAK
INSTABILITY WILL BE OVER THE FAR WEST AND WILL HAVE VCTS ONLY AT
KJAC FOR NOW. SOME SHOWER ACTIVITY WILL CONTINUE THROUGH THE
OVERNIGHT HOURS. MOUNTAINS WILL BE OBSCURED THIS MORNING.

&&

.FIRE WEATHER...

FIRE DANGER RELATIVELY LOW INTO WEDNESDAY AS SEASONAL TO COOL AND
RELATIVELY MOIST CONDITIONS PERSIST. LOW PRESSURE WILL PASS TO THE
SOUTH OF WYOMING TODAY AND BRING A WETTING RAIN TO MUCH OF THE
AREA...ESPECIALLY THE SOUTHERN TWO THIRDS OF THE STATE. SEVERAL
INCHES OF SNOW IS POSSIBLE IN THE WESTERN MOUNTAINS THROUGH TONIGHT.
IT WILL DRY OUT SOMEWHAT FOR WEDNESDAY...BUT THE CHANCE OF SOME
SHOWERS AND THUNDERSTORMS WILL PERSIST...ESPECIALLY ACROSS THE SOUTH
AND WEST.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MDT WEDNESDAY WYZ009-015.

&&

$$

SHORT TERM...PS
LONG TERM...KPL
AVIATION...WM
FIRE WEATHER...PS







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