Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 030552
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1150 PM MDT SUN AUG 2 2015

UPDATE...ADDED 06Z AVIATION DISCUSSION

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED 237 PM MDT)

A FEW AREAS OF CUMULUS DEVELOPING ACROSS THE CENTRAL MOUNTAINS THIS
AFTERNOON. THE CENTRAL MOUNTAINS REMAIN THE MOST FAVORABLE LOCATION
FOR SHOWER OR THUNDERSTORM DEVELOPMENT THIS AFTERNOON...THOUGH
COVERAGE WILL BE LIGHT. A FEW SHOWERS WILL REMAIN THROUGH THE
OVERNIGHT HOURS...WITH DEVELOPMENT SPREADING INTO SOUTHERN WYOMING
AS WELL.

MONDAY WILL SEE THE CONTINUED ADVANCEMENT OF THE WAVE OF LOW
PRESSURE THROUGH THE DESERT SOUTHWEST AND HEADING NORTH TO SOUTHERN
WYOMING. AHEAD OF ITS ARRIVAL...CLOUD COVER WILL INCREASE MONDAY
LATE MORNING AND THROUGH THE AFTERNOON. SURGES OF MOISTURE WILL
BEGIN TO IMPACT SOUTHERN WYOMING MONDAY MORNING...WITH SHOWER
COVERAGE INCREASING THROUGH THE AFTERNOON. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS MUCH OF THE
FORECAST AREA BY THE AFTERNOON HOURS...WITH THE BEST COVERAGE NOTED
OVER AREA WEST OF THE CONTINENTAL DIVIDE. PWATS ASSOCIATED WITH THIS
SYSTEM ARE MOST IMPRESSIVE ACROSS THE SOUTH AND WEST. WITH VALUES
SHOWING OVER AN INCH...CONTINUED THE INCLUSION OF HEAVY RAIN WORDING
WITH ANY PRESENT STORM ACTIVITY.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

SHORTWAVE ROTATING SLOWLY NORTH ACROSS THE FORECAST AREA MONDAY
NIGHT THROUGH AT LEAST MIDDAY TUESDAY. NAM AND EC ARE SLOWER WITH
THE PROGRESSION OF THIS SYSTEM AND PREFER THEIR SOLUTIONS TO THAT
OF THE FASTER GFS GIVEN CURRENT TRENDS WITH THIS SYSTEM. HAVE
INCREASED PRECIPITATION CHANCES MONDAY EVENING IN MANY AREAS AND
AGAIN TUESDAY AFTERNOON ACROSS THE NORTH. PLENTY OF MOISTURE
AVAILABLE WITH PRECIPITABLE WATER VALUES TOPPING ONE INCH ALONG
AND AHEAD OF THE SHORTWAVE. STEERING WINDS ARE FAVORING SLOW-
MOVING STORMS. BELIEVE THAT THIS COMBINATION SETS THE STAGE FOR
POSSIBLE FLASH FLOODING... PARTICULARLY OVER THE HIGHER TERRAIN.
COULD FORESEE SITUATIONS WHERE RAINFALL OF 1 INCH IN 30-60 MINUTES
WOULD BE A DISTINCT POSSIBILITY OVER THE SOUTHWEST MONDAY EVENING
AND AGAIN OVER THE BIGHORN MOUNTAINS AND SURROUNDING FOOTHILL
LOCATIONS TUESDAY AFTERNOON AND EARLY EVENING. DEVELOPING LOW OVER
THE NORTHEAST WYOMING PLAINS WILL ALSO AID MOISTURE CONVERGENCE
AND LIFT TUESDAY AFTERNOON IN OUR NORTHEASTERN ZONES. CONDITIONS
WILL IMPROVE ACROSS THE SOUTHWEST TUESDAY MORNING IN THE WAKE OF
THE SHORTWAVE. EXPECT GUSTY WESTERLY WIND IN SWEETWATER...SUBLETTE
AND LINCOLN COUNTIES DURING THE DAY. TO THE NORTH...WOULD EXPECT
FAVORED NORTHWEST WIND LOCATIONS IN THE EASTERN BIG HORN BASIN AND
NORTHERN JOHNSON COUNTY TO BLOW AS THE SHORTWAVE CLEARS THE
REGION. HAVE INCREASED WIND SPEEDS IN THESE TWO LOCALES. AFTER A
BRIEF RESPITE TUESDAY NIGHT...NEXT SHORTWAVE COMES ACROSS THE WEST
AND NORTHWEST WEDNESDAY AFTERNOON AND EVENING ACCOMPANIED BY A
80-90KT 250MB JET STREAK. STORMS WILL MOVE WEDNESDAY...SO FLASH
FLOOD THREAT LOOKS TO BE MINIMAL...BUT FAVORABLE MID-LEVEL WINDS
COULD LEAD TO GUSTY OUTFLOW WIND. COULD BE LINGERING ISOLATED
CONVECTION ACROSS THE FAR NORTH THURSDAY...BUT OVERALL EXPECT
DRYING TREND FOR THURSDAY AND FRIDAY. MOISTURE BEGINS TO INCREASE
FROM THE SOUTHWEST EARLY SATURDAY IN RESPONSE TO SHORTWAVE MOVING
ONSHORE IN CALIFORNIA. ENERGY ASSOCIATED WITH THIS SYSTEM WILL
TRAVERSE THE FORECAST AREA NEXT WEEKEND WITH TYPICAL SUMMERTIME
CONVECTION. AS FOR TEMPERATURES...EXPECT GENERALLY SEASONAL
TEMPERATURES THROUGH THE WEEK AND INTO NEXT WEEKEND. COOLEST DAYS
WOULD BE TUESDAY ACROSS THE NORTH WITH MORE EXTENSIVE CLOUD COVER
UNTIL LATE IN THE DAY...AND THURSDAY IN THE WAVE OF WEDNESDAY
SHORTWAVE.


&&

.AVIATION.../06Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE SYSTEM OVER NORTHERN UTAH WILL DRIFT NE
ACROSS WYOMING MONDAY AND MONDAY NIGHT.  THIS SYSTEM WILL SPREAD SCT-
NMRS SHRA AND ISOLD TSRA VCNTY AND SOUTH OF INTERSTATE 80 12Z-
18Z...TO VCNTY AND SOUTH OF A KCPR-KRIW-KJAC LINE BY 00Z TUESDAY.
AREAS OF MVFR CONDITIONS WITH LCL IFR CONDITIONS ALONG WITH
INCREASING MTN OBSCURATIONS WILL DEVELOP ALONG THE LINE OF -
SHRA/TSRA PUSHING NORTH.  THE LINE OF SHRA WITH AREAS OF MVFR/LCL
IFR CONDITIONS AND FQT MTN OBSCURATIONS WILL BE MAINLY ALONG AND
EAST OF THE CONTINENTAL DIVIDE BY 12Z TUESDAY WITH A DRIER WESTERLY
FLOW PUSHING INTO SW WYOMING ALONG WITH IMPROVING CIGS.

&&

.FIRE WEATHER...

A FEW SHOWERS NOTED ACROSS CENTRAL AND SOUTHERN WYOMING THROUGH THE
EVENING AND OVERNIGHT HOURS. AN APPROACHING WAVE OF LOW PRESSURE
WILL SPREAD CLOUD COVER AND ISOLATED SHOWERS AND THUNDERSTORMS
ACROSS THE SAME AREAS EARLY MONDAY. COVERAGE WILL INCREASE THROUGH
THE AFTERNOON...WITH HEAVY RAINFALL POSSIBLE ACROSS SOUTHERN AND
WESTERN WYOMING. MORE WIDESPREAD SHOWER AND THUNDERSTORM COVERAGE
WILL CONTINUE THROUGH TUESDAY MORNING...WITH ACTIVITY WANING FROM
NORTH TO SOUTH TUESDAY AFTERNOON AND EVENING.

&&

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

$$

SHORT TERM...BRANHAM
LONG TERM...CNJ
AVIATION...AEM
FIRE WEATHER...BRANHAM



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