Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 250523
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1123 PM MDT FRI OCT 24 2014

.SHORT TERM...TONIGHT THROUGH SATURDAY

MID LEVEL CLOUDS WILL MOVE NORTH OF OUR CWA TONIGHT. TRAPPED MTN
WAVES ARE EVIDENT ON SATL WITHIN THOSE CLOUDS OVER NORTHERN WY.
WINDS AT CHIEF JOSEPH HAVE BEEN GUSTING TO OVER 50 MPH BUT WILL
CONTINUE TO DECREASE FOR THE REMAINDER OF THIS AFTERNOON.
HOWEVER...THE FAST WESTERLY FLOW WILL CONTROL THE WEATHER THROUGH
SATURDAY. THIS WILL RESULT IN FAIRLY BREEZY WEST SOUTHWESTERLY
WINDS ...MILD AND DRY CONDITIONS THROUGH THE PERIOD. HIGH
TEMPERATURES WILL LIKELY RUN ABOUT 15 DEGREES ABOVE NORMAL. THE
WINDS WILL GRADUALLY INCREASE LATER SATURDAY AFTERNOON AS THE NEXT
PACIFIC TROUGH APPROACHES WITHIN THE BACKING STEERING WINDS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

ANOTHER WIND EVENT IS POSSIBLE IN THE ABSAROKAS AND CODY FOOTHILLS
SATURDAY NIGHT AS INCREASING H7 FLOW TO 35-45KTS POTENTIALLY COMBINE
WITH AN ENCROACHING JET...JUST ABOVE MTN TOP INVERSION AND
EVEN SOME MODERATE GAP FLOW SIGNATURE TO AT LEAST WARRANT A WATCH.
THE WRF IS SHOWING 35KT AT H7 UPSTREAM OF THE ABSAROKA PLATEAU WITH
80KTS ON THE EAST SLOPE LATER SUNDAY NIGHT WITH 35-40KT BOUNDARY
LAYER WINDS SURFACING ON HIGHWAY 120 WITH 60-70KTS ALONG THE
FOOTHILLS. WRF CROSS SECTION IS NOT SHOWING ANY CRITICAL LAYER BUT
ENOUGH PARAMETERS PRESENT TO AT LEAST PUT UP THE WATCH AND ALLOW
LATER SHIFTS TO MONITOR THE POTENTIAL. OTHERWISE...QUITE A BIT OF
WIND IN MUCH OF THE AREA SATURDAY NIGHT AND SUNDAY AS ERN PACIFIC/
GULF OF ALASKA LOW MOVES INLAND. SRN UPPER LOW LIFTS NE FIRST
SATURDAY NIGHT WITH FIRST SHOT OF LIGHT PCPN IN THE FAR WEST BEFORE
THE COLDER TROUGH TO THE NW MOVES IN. MAIN CHANGE TODAY IS LESS
SUPPORT FROM THE NRN PART OF THIS TROUGH ON MONDAY. MORE SHEARING
AND FURTHER NORTH TRACK BEING SHOWN WITH LESS SUPPORT IN WYO FOR
PCPN ON MONDAY. STILL LOOKING AT SNOW IN THE WRN MOUNTAINS SUNDAY
INTO SUNDAY NIGHT WITH A CHANCE OF RAIN EAST OF THE DIVIDE...MAINLY
NORTH SUNDAY NIGHT INTO MONDAY. RAIN COULD MIX WITH OR BRIEFLY
CHANGE TO SNOW LATER SUNDAY NIGHT OR EARLY MONDAY BUT LITTLE OR NO
ACCUMULATION IS EXPECTED. EVEN LESS OF A CHANCE OF PCPN FURTHER WEST
IN THE WIND RIVER BASIN. STILL A MILD DAY EAST OF THE DIVIDE BEFORE
COLD FRONT MOVES EAST AND SE ACROSS THE AREA. MUCH COOLER MONDAY.

BRIEF RIDGING WITH TEMPS RECOVERING TUESDAY BUT THEN A FAST MOVING
SYSTEM HITS THE FAR WEST TUESDAY NIGHT WITH SOME MOIST...ISENTROPIC
UPGLIDE. THE SHORTWAVE THEN MOVES ACROSS THE AREA ON WEDNESDAY WITH
A DECENT CHANCE OF HIGHER ELEVATION SNOW AND LOWER ELEVATIONS RAIN
IN THE WEST AND FAR NORTH. FURTHER SOUTH...THE MAIN EFFECT WILL BE
CLOUDS AND STRONG TO HIGH WINDS. SHORTWAVE MOVES OFF WEDNESDAY NIGHT
WITH A RIDGE MOVING BACK IN THURSDAY AND FRIDAY. GFS HAS COME IN
LINE WITH THE ECMWF TODAY WITH A MORE SIGNIFICANT RIDGE HOLDING
ACROSS THE AREA THROUGH NEXT FRIDAY AT LEAST. MID LEVEL TEMPERATURES
RISE TO BETWEEN +6 AND +8 ACROSS THE SOUTH HALF BY FRIDAY AFTERNOON.
RIDGE AXIS NEARLY OVERHEAD ON FRIDAY MAY HAMPER FULL MIXING BUT
STILL A MILD END TO A ABNORMALLY WARM OCTOBER.

&&

.AVIATION.../06Z ISSUANCE/

VFR CONDITIONS UNDER SKC CONDITIONS ARE EXPECTED THROUGH 00Z SUNDAY.
BREEZY TO WINDY SOUTH TO SOUTHWEST WIND IN TYPICAL AREAS DURING THE
DAY SATURDAY...WITH AN APPROACH OF A STORM SYSTEM. AFTER 00Z...AREAS
WEST OF THE DIVIDE WILL SEE QUICKLY INCREASING MID LEVEL CLOUDINESS
WITH SOME SHOWER ACTIVITY POSSIBLE AFTER 03Z. MOUNTAIN TOPS WILL
BECOME OBSCURED OVER THE FAR WEST BETWEEN 03Z AND 06Z. SOME MVFR
CONDITIONS COULD OCCUR IN OR NEAR THIS CONVECTION.  HOWEVER OF MORE
CONCERN...WILL BE CONSIDERABLE MOUNTAIN TURBULENCE SATURDAY NIGHT AS
WELL AS...LLWS ON THE LEE SIDE OF MOUNTAIN RANGES...ESPECIALLY AT
COD AND LND.

PLEASE SEE THE AVIATION WEATHER CENTER FOR THE LATEST INFORMATION ON
TURBULENCE FORECASTS.

&&

.FIRE WEATHER...

FIRE DANGER WILL BECOME SOMEWHAT ENHANCED THROUGH
SATURDAY...PRIMARILY ACROSS BASINS AND VALLEYS EAST OF THE DIVIDE ON
SATURDAY AS WELL AS ACROSS NATRONA COUNTY. MINIMUM RH VALUES ACROSS
THESE AREAS WILL FALL INTO THE MID AND UPPER TEENS WHILE WINDS
INCREASE OUT OF THE SOUTHWEST TO 15 TO 25 MPH WITH HIGHER GUSTS AT
TIMES. VERY WINDY CONDITIONS ARE EXPECTED IN SOME OF THE ZONES
SATURDAY NIGHT. SUNDAY...MOISTURE WILL INCREASE ACROSS THE ENTIRE
REGION WITH A BETTER CHANCE FOR SHOWERS ACROSS THE NORTH AND
WEST...LOWERING FIRE DANGER ONCE AGAIN.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING
WYZ002-003.

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...WM
FIRE WEATHER...LIPSON








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