Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 302038
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
238 PM MDT TUE JUN 30 2015

.SHORT TERM...TONIGHT THROUGH WEDNESDAY

WV IMAGERY SHOWS LARGE BROAD RIDGE OVR THE WRN CONUS...WITH A WEAK
DISTURBANCE MOVING THRU THE NRN FA THIS MORNING AND A STRONGER ONE
UPSTREAM OVR CNTRL MT THAT WILL AFFECT ERN WY AND POSSIBLY THE ERN
ZONES LATER TODAY. SFC SHOWS WEAK HIGH P OVR WY WITH A SLOW MOVING
SFC FRONT ACROSS ERN MT THIS MORNING.

OVERALL...SCATTERED SHOWERS AND EMBEDDED THUNDERSTORMS ASSOCIATED
WITH THE UPR LVL DISTURBANCE PUSHING THE FRONT SWD THRU THE CWA THIS
AFTERNOON. A FEW STRONG OR NEAR SEVERE...PARTICULARLY FROM ERN
FREMONT...EWD TO JOHNSON AND NATRONA COUNTIES THIS AFTERNOON. POST
FRONTAL...COOLER AND DRIER WED WITH MUCH LESS CHANCE FOR MEASURABLE
PRECIPITATION. BEST CHANCES FOR THUNDER WED WILL OCCUR ON A ISOLATED
BASIS LATER IN THE AFTERNOON ACROSS THE SERN PORTION OF THE CWA.

OTHERWISE...CLOUDS ON THE INCREASE ACROSS THE CWA TODAY...FILLING IN
FROM N TO S. PWS HAVE ALREADY INCREASED THIS MORNING FROM AROUND
0.6IN TO NEAR OR JUST ABOVE 1 INCH OVR THE CNTRL...NRN AND NERN FA.
SFC FRONT WILL ENTER THE NRN FA THIS AFTERNOON...WITH LIFT PROVIDE
ENOUGH OF A TRIGGER TO AID IN INCREASING SHOWERS AND EMBEDDED
THUNDER FROM N TO S THIS AFTERNOON AND EARLY EVENING. FCST SOUNDINGS
SHOW RELATIVELY LONG NARROW CAPE...AND WITH INCREASING UPR LVL FLOW
AND SHEAR THRU MUCH OF THE AFTERNOON...WITH A FEW STORM CORES WILL
BE ABLE TO PRODUCE HEAVY RAIN IN SHORT ORDER...WITH POSSIBLE
LOCALIZED FLASH FLOODING. THIS WILL BE ESPECIALLY TRUE IN AREAS OF
POST FRONTAL TERRAIN FORCED CONVERGENCE...FROM THE SRN ABSAROKAS AND
SRN BIGHORNS...AND THE REGION IMMEDIATELY ADJACENT TO AND SOUTH OF
THE BIGHORN MOUNTAINS. ADDITIONALLY...A FEW OF THE STRONGER STORMS
WILL PRODUCE NOT ONLY HEAVY RAIN...BUT STRONG (WET) WINDS AND SMALL
TO MARGINALLY SEVERE HAIL...ESPECIALLY FROM ERN FREMONT COUNTY...EWD
AND OVR BOTH JOHNSON AND NATRONA COUNTIES AFTER 4 PM. WILL HAVE TO
MONITOR THE SITUATION AS CLOUD COVER...OR THE LACK THEREOF IN
PLACES...WILL AT LEAST PARTIALLY DICTATE STORM INITIATION AND MODE
EARLY ON. BEST ML CAPE AROUND THE FA WILL RUN AROUND 1000 TO 1500
J/KG WITH SHEAR INCREASING TO 25 TO 35 KTS IN POST FRONTAL FLOW BY
THE TIME EVENING BEGINS. HODOGRAPHS ARE LONG AND FAIRLY STRAIGHT
AHEAD OF THE FRONT...BECOMING MORE CYCLONIC LATE AS THE FRONT MOVES
THROUGH. SPLITTING STORM WILL BE POSSIBLE AHEAD OF THE FRONT...WITH
STRONGEST STORMS OF THE DAY WILL BE ON OR VERY NEAR THE FRONT
ITSELF...BECOMING RAPIDLY MORE ELEVATED NORTH OF THE FRONT...BUT
STILL REMAINING STRONG FOR AT LEAST A SHORT WHILE UNDER THE
INCREASING SHEAR.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

NORTHWEST FLOW ASSOCIATED WITH HIGH PRESSURE OVER THE DESERT
SOUTHWEST WILL CONTINUE. SOME MOISTURE WILL RIDE ALONG THE NORTHWEST
FLOW TO BRING AFTERNOON SHOWERS AND THUNDERSTORMS...ESPECIALLY OVER
THE MOUNTAINS. OVERALL...INDEPENDENCE DAY LOOKS TO FAIRLY
QUIET...WITH WARM CONDITIONS. A FEW SHOWERS AND THUNDERSTORMS WILL
BE AROUND TO BRING NATURAL FIREWORKS...THOUGH ACTIVITY SHOULD
GENERALLY BE CONFINED TO THE MOUNTAINS.

THE RIDGE OF HIGH PRESSURE WILL BEGIN TO BREAKDOWN LATE SATURDAY. A
WAVE OF LOW PRESSURE MOVES ALONG SOUTHERN CANADA TO FLATTEN THE
RIDGE. THIS FLATTER FLOW WILL NOT PERMIT MUCH IN THE WAY OF MOISTURE
ACROSS THE AREA...WITH LIMITED SHOWER ACTIVITY EXPECTED. THE RIDGE
OF HIGH PRESSURE WILL THEN LOSE MUCH OF ITS INFLUENCE...PERMITTING
ADDITIONAL MOISTURE TO IMPACT THE AREA.

EXPECT MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ACROSS THE AREA
LATE SUNDAY AND INTO THE EARLY PORTION OF THE WEEK.


&&

.AVIATION.../00Z ISSUANCE/

VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST.
HOWEVER...SCATTERED SHOWERS AND EMBEDDED THUNDERSTORMS...A FEW
STRONG...WILL DEVELOP FROM NORTH TO SOUTH ACROSS WYOMING...MOVING
FROM NORTHWEST TO SOUTHEAST AT AROUND 25 MPH...WITH SOME TERMINAL
SITES SEEING BRIEF MVFR CONDITIONS DUE TO LOWER CIGS AND REDUCED
VISIBILITY IN HEAVY RAIN. SKIES WILL THEN BEGIN TO CLEAR TONIGHT
FROM NORTH TO SOUTH. ISOLATED THUNDERSTORMS WILL AGAIN BE POSSIBLE
EAST OF AN KBYG TO KRKS LINE.


&&

.FIRE WEATHER...

FIRE DANGER WILL REMAIN BELOW CRITICAL AS THE ATMOSPHERE BECOMES
CHARGED WITH MOISTURE TODAY ACROSS MOST OF THE FORECAST AREA AND
FUELS REMAIN IN GREEN-UP. HOWEVER...FIRE DANGER WILL STILL BE
ENHANCED TODAY AND TOMORROW...PARTICULARLY ACROSS THE SOUTHERN
FORECAST AREA...AS VERY WARM DAYTIME TEMPERATURES COMBINE WITH
MINIMUM RH VALUES IN THE UPPER TEENS AND GUSTY FRONTAL INDUCED WINDS
OCCASIONALLY GUSTING GREATER THAN 25 MPH FOR SHORT PERIODS...OR
PERHAPS A BIT HIGHER NEAR THUNDERSTORMS. WEDNESDAY WILL BE COOLER
WITH LESS CHANCES FOR PRECIPITATION.

&&

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

$$

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



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