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000
FXUS65 KRIW 152103
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
303 PM MDT SAT JUN 15 2013

.SHORT TERM...TONIGHT THROUGH SUNDAY
NEARLY ZONAL UPPER FLOW/PRE DIRTY RIDGE CONDITIONS WITH SFC HIGH
PRESSURE TODAY...GIVING THE CWA ONE OF THE BETTER DAYS OF THE YEAR.
ONLY VERY SLIM CHANCE FOR CONVECTION WITH PRECIP CHANCES OFF OF OR
NEAR CASPER MOUNTAIN AREA THIS AFTERNOON. OTHERWISE...OROGRAPHICALLY
ENHANCED CIRRUS WILL BE THE MAIN THREAT TODAY AS EVEN THE WINDS WILL
TAKE A BREAK ACROSS THE REGION.

TONIGHT...AS WEAK SFC LOW/INVERTED TROUGH TRIES TO BUILD IN TO S
CNTRL WY FROM THE UINTA AREA OF UTAH...RETURN OF SOME MODEST
BOUNDARY LAYER MOISTURE WILL BEGIN IN LL SERLY FLOW TO OUR EASTERN
ZONES WITH...ALMOST WARM FRONT-ISH.

SUNDAY...UPPER LEVEL RIDGE AXIS TRIES TO VERY SLOWLY ENCROACH FROM
THE WEST ALLOWING SOME DIRTY MOISTURE MID LVL TO MAKE ITS WAY BACK
IN...WHILE UNDERNEATH COMPLEX BOUNDARY AND LL FLOW CONDITION WILL
EXIST AS WEAK LOW AND PSEUDO WARM FRONT DOES BATTLE WITH WEAK LOW
AND COOL FRONT CURRENTLY LOCATED IN SRN CANADA. MODELS INDICATING
NORTHERN FRONT WILL WIN OUT ATTM BRINGING N TO NNE LL FLOW INTO THE
ERN CWA BY MID-DAY AND LEAVING US WITH A CONVERGENCE ZONE STRETCHING
FROM ROUGHLY THE LANDER AREA ESE TO THE SHIRLEY BASIN REGION. IF
TIMING OF CONVERGENCE HOLDS OUT...THIS WOULD GIVE BEST POTENTIAL FOR
MODEST THUNDER ALONG AND NEAR THE GREEN MOUNTAINS...PERHAPS NORTH TO
THE RATTLESNAKE RANGE...THEN UP TO THE THE VERY SOUTHERN EXTENT OF
THE BIG HORN MOUNTAINS AND/OR ACROSS TO THE CASPER MOUNTAIN AREA.
SIMILAR CHANCES FOR THUNDERSTORMS WILL ALSO OCCUR OVER THE USUAL
HIGH ELEVATIONS OF WESTERN MOUNTAINS...PERHAPS STRAYING A BIT INTO
THE LOWER ADJACENT VALLEYS AND BASINS. BIG HORN BASIN LOOKS TO BE
THE MOST PROTECTED AND LEAST LIKELY PLACE FOR THUNDER SUNDAY
HOWEVER...WHICH IS QUITE A CHANGE FROM EARLIER THIS WEEK. OVERALL
SITUATION DOES NOT LOOK SEVERE ATTM...WITH ONLY MODEST INSTABILITY
AVAILABLE. EVEN FCST DCAPE LOOKS TO REMAIN IN CHECK AT LESS THAN 500
J/KG WRN 2/3 CWA...GUSTY ERRATIC NEAR STORMS...BUT NOT SEVERE HERE.
BETTER CHANCE FOR STRONG GUSTS OVER AND NEAR/ADJACENT AREAS TO
NATRONA COUNTY AS DCAPE TRENDS RISE TO NEAR 1000J/KG.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

A RIDGE OF HIGH PRESSURE WILL CONTINUE TO BUILD OVER THE AREA SUNDAY
NIGHT...WITH SOME EMBEDDED DISTURBANCES RESULTING IN SOME ISOLATED
EVENING SHOWERS AND THUNDERSTORMS. DRY CONDITIONS THEN BUILD OVER
THE AREA LATE IN THE EVENING...AND PERSIST FOR A FEW HOURS.

THE NEXT ROUND OF DISTURBANCES MAY RESULT IN SOME ISOLATED SHOWERS
AND THUNDERSTORMS. COVERAGE WILL INCREASE THROUGH THE MORNING...WITH
SOME SCATTERED ACTIVITY NOTED IN THE AFTERNOON. THIS PATTERN OF
DRYING OVERNIGHT WITH A RETURN OF MOISTURE AND SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON WILL REMAIN THROUGH TUESDAY ACROSS
MUCH OF WESTERN AND CENTRAL WYOMING.

A SLIGHTLY LONGER PERIOD OF LESSENED SHOWER ACTIVITY IS ANTICIPATED
BY TUESDAY EVENING. AN AREA OF LOW PRESSURE WILL BE PRESENT ACROSS
THE PACIFIC NORTHWEST...THOUGH ITS SHOWER ACTIVITY IS NOT
ANTICIPATED TO REACH INTO MUCH OF WYOMING UNTIL PERHAPS THURSDAY.
THE CORE OF THE LOW PRESSURE SYSTEM IS ANTICIPATED TO REMAIN NORTH
OF THE FORECAST AREA...KEEPING MOST SHOWER ACTIVITY CONFINED TO THE
NORTHERN THIRD OF THE STATE.

WARMING AND DRY CONDITIONS WILL BE FOUND ACROSS MUCH OF THE
REMAINDER OF THE STATE. LOW HUMIDITY IS ANTICIPATED WITH WARMING
TEMPERATURES...WHICH MAY COMBINE WITH INCREASED AFTERNOON WIND. THIS
COMBINATION MAY RAISE CONCERNS FOR THE FIRE WEATHER
COMMUNITY...THOUGH SOURCES STILL INDICATE THAT FUELS AROUND THE AREA
ARE STILL NOT CONSIDERED CRITICAL. FUEL STATUS WILL BE MONITORED
DURING THE EARLY PORTION OF THE WEEK TO CHECK FOR
UPDATES...ESPECIALLY GIVEN THE CURRENT FORECAST. SOUTHERN WYOMING
IS...AS USUAL THE MOST SUSCEPTIBLE AREA TO SEE STRONGER AFTERNOON
WIND...ESPECIALLY IN THE SOUTHWESTERLY FLOW ANTICIPATED THROUGH MUCH
OF THE FORECAST PERIOD. PERIODS OF THESE HAZARDOUS CONDITIONS MIGHT
BE FOUND THROUGH THE REMAINDER OF THE WORK WEEK.


&&

.AVIATION.../00Z ISSUANCE/
MOSTLY BENIGN WEATHER CONTINUES ACROSS THE FORECAST AREA THROUGH
MOST OF THE FORECAST PERIOD...GIVING WIDESPREAD VFR CONDITIONS.
SUNDAY WILL BRING A MODERATE INCREASE IN MOISTURE WITH CHANCES FOR
ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS NEAR
TERMINALS IN OR VERY NEAR THE MOUNTAINS LATE IN THE AFTERNOON AND
EVENING. HAVE LEFT OUT VCSH OR VCTS FROM EXTENDED PORTION OF
FORECAST AT THE MOMENT AS STORM INITIATION LOOKS TO BE VERY CONDITIONAL ON
THE PLACEMENT OF LOW LEVEL CONVERGENCE FROM AIR MASS BATTLES DURING
THE DAY.


&&

.FIRE WEATHER...
BEAUTIFUL STABLE CONDITIONS MOST ZONES TODAY...UT DRY WITH MINIMUM
RH VALUES FALLING INTO THE SINGLE DIGITS ACROSS THE SOUTHERN
ZONES...WITH ONLY TEENS EVERYWHERE ELSE. WINDS WILL NOT BE AS
DRAMATIC THE REST OF TODAY AS THEY WERE THE PAST FEW DAYS.
STILL...GUSTS TO 20/25 MPH CAN BE EXPECTED OFF THE SURFACE AT
TIMES...PARTICULARLY ALONG RIDGE TOPS. SOME MODERATE INCREASE IN
MOISTURE WILL BRING ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS INTO THE FORECAST FOR SUNDAY AFTERNOON AND
EVENING...ESPECIALLY OVER AND NEAR THE MOUNTAIN RANGES.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...BRANHAM
AVIATION...BRAUN
FIRE WEATHER...BRAUN