Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 171148
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
548 AM MDT WED SEP 17 2014

.UPDATE...

A NARROW BAND OF THUNDERSTORMS HAVE FORMED ACROSS EASTERN IDAHO
INTO WESTERN WYOMING THIS MORNING...WHILE SOME LIGHT SHOWER
ACTIVITY CONTINUES OVER JOHNSON AND NATRONA COUNTIES. MUCH OF THE
THUNDERSTORM ACTIVITY OUT WEST THROUGH 9 AM WILL IMPACT AREAS
BETWEEN JACKSON AND ALPINE/BONDURANT. THE ACTIVITY IS EXPECTED TO
DISSIPATE AS IT MOVES OVER THE DIVIDE...AND BEGIN TO WEAKEN BY MID
MORNING...BEFORE REDEVELOPING IN THE EARLY AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 244 AM MDT WED SEP 17 2014/

SHORT TERM...TODAY THROUGH FRIDAY NIGHT

SHOWER ACTIVITY WILL CONTINUE TO MOVE THROUGH PORTIONS OF THE
FORECAST AREA THIS MORNING. AN ISOLATED LIGHTNING STRIKE IS NOT OUT
OF THE QUESTION. THE RIDGE OF HIGH PRESSURE REMAINS OVER THE AREA
WITH WARMING TEMPERATURES EXPECTED OVER THE NEXT COUPLE DAYS. GUSTY
WIND WILL DEVELOP OVER SOUTHERN WYOMING DURING THE AFTERNOON
HOURS...WITH WIND WEAKENING THROUGH THE EVENING HOURS.

THE RIDGE OF HIGH PRESSURE CONTINUES TO SLIDE EAST THROUGH THE
FORECAST AREA OVER THE NEXT FEW DAYS...WITH THE AXIS REACHING
OUTSIDE OF CWA BOUNDARIES BY LATE THURSDAY MORNING. ANOTHER PUSH OF
MOISTURE EXPECTED WITH THE DEPARTURE OF THE RIDGE...ESPECIALLY
IMPACTING THE WESTERN MOUNTAINS. IN ADDITION... A COLD FRONT WILL
SWEEP THROUGH THE AREA LATE THURSDAY AND INTO FRIDAY. COOLER
TEMPERATURES ARE EXPECTED WITH INCREASING MOISTURE. SHOWERS AND
THUNDERSTORMS REMAIN MOST FAVORABLE OVER THE WESTERN ZONES.

LONG TERM...SATURDAY THROUGH WEDNESDAY

IN WAKE OF THE SYSTEM FRIDAY...MAINLY DRY CONDITIONS ARE EXPECTED
SATURDAY WITH SLIGHTLY ABOVE AVERAGE TEMPERATURES. A CUT OFF UPPER
LOW OVER CALIFORNIA SATURDAY IS PROJECTED BY GLOBAL MODELS TO PUSH
INTO THE GREAT BASIN SUNDAY AND THEN INTO THE COWBOY STATE MONDAY.
THIS WOULD PUSH SOME CONVECTION INTO THE SOUTH/SOUTHWEST SUNDAY AND
OVER MUCH OF THE AREA MONDAY IF THIS TRACK COMES TO FRUITION. MAINLY
DRY CONDITIONS WITH SEASONAL TO SLIGHTLY ABOVE AVERAGE TEMPS RETURN
TUESDAY AND WEDNESDAY.

AVIATION.../12Z ISSUANCE/

ISOLATED THUNDERSTORMS WILL IMPACT AREAS BETWEEN KJAC AND
KAFO...AS WELL AS KJAC AND KPNA THROUGH AT LEAST 15Z. THIS
ACTIVITY IS EXPECTED TO DECREASE AFTER 15Z...BUT REDEVELOP BY
19-20Z. THIS AFTERNOON ACTIVITY WILL PROGRESS EASTWARD AND IMPACT SOME
PLACES EAST OF THE CONTINENTAL DIVIDE FROM 21Z UNTIL 03Z THURSDAY.
OUTFLOW WIND GUSTS TO 35 KNOTS WILL BE LIKELY AT TIMES NEAR
STORMS. VFR CONDITIONS WILL OCCUR THROUGH THE FORECAST
PERIOD...EXCEPT NEAR THUNDERSTORMS WHERE BRIEF MVFR/IFR CONDITIONS
WILL OCCUR.

FIRE WEATHER...

THE RIDGE OF HIGH PRESSURE REMAINS OVER THE AREA THROUGH THURSDAY.
HOWEVER...ENOUGH MOISTURE WILL MOVE INTO THE AREA TO GENERATE SOME
AFTERNOON SHOWERS AND THUNDERSTORMS. ADDITIONALLY...SOME GUSTY WIND
WILL DEVELOP ACROSS SOUTHERN WYOMING WHERE DAYTIME HUMIDITY MAY DIP
INTO THE LOW TEENS. WHILE THIS MAY IMPACT FIRE WEATHER
BEHAVIOR...CONDITIONS WILL NOT BE CRITICAL AS FUELS ACROSS THE
IMPACTED AREAS ARE CURRENTLY LISTED AS NOT CRITICAL. A COLD FRONT
MOVING THROUGH THE AREA LATE THURSDAY AND THROUGH FRIDAY WILL BRING
A WIND SHIFT ACROSS THE AREA...WITH INCREASING SHOWER
COVERAGE...ESPECIALLY OVER WESTERN WYOMING.

&&

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

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...AR/WM
FIRE WEATHER...BRANHAM





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