Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 281735
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1135 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

...UPDATE...
LOW CLOUDS AND FOG HAVE FINALLY DISSIPATED LEAVING A SUNNY TO
MOSTLY SUNNY SKY.

LIGHT SHOWERS NOTED ACROSS THE SOUTHEASTERN HALF OF THE FORECAST
AREA THIS MORNING. THE CORE OF THE LOW PRESSURE IS OVER
NORTHEASTERN COLORADO AND IS CONTINUING ON ITS EASTWARD
PROGRESSION. SHOWERS WILL CONTINUE TO TAPER OFF AS THE SYSTEM
MOVES FURTHER EAST...WITH NATRONA AND SWEETWATER COUNTIES LOOKING
TO HOLD ON TO SHOWER ACTIVITY THE LONGEST.

DRY NORTHWEST FLOW BUILDS OVER THE AREA THIS EVENING UNDER THE
INFLUENCE OF A FLATTENED RIDGING PATTERN. THIS SYSTEM WILL ALLOW
SURGES OF MOISTURE TO MOVE INTO THE FORECAST AREA...ESPECIALLY
NORTHWESTERN WYOMING. SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE...WITH ASSOCIATED THREATS OF GUSTY WIND AND LIGHTNING
ACTIVITY.

ANOTHER TROUGH ADVANCES TOWARDS THE FORECAST AREA BY SATURDAY
MORNING...BRINGING INCREASING SOUTHWEST FLOW OVER THE AREA. GUSTY
WINDS WILL BE POSSIBLE UNDER THIS FLOW...WITH DRIER CONDITIONS NOTED
OVER SOUTHERN WYOMING AHEAD OF THE TROUGH. THIS MAY LEAD TO SOME
ELEVATED FIRE WEATHER CONCERNS...BUT THE SITUATION WILL CONTINUE TO
BE MONITORED.

THE TROUGH WILL STRENGTHEN OVER THE AREA SATURDAY AFTERNOON AND
EVENING...WITH MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
ANTICIPATED. AGAIN...GUSTY WIND AND LIGHTNING WILL BE THE PRIMARY
THREATS WITH STORM ACTIVITY OVER THE NEXT FEW DAYS. THE TROUGH WILL
GENERALLY MOVE THROUGH THE AREA BY SUNDAY MORNING...WITH A RETURN OF
DRY NORTHWEST FLOW.

.LONG TERM...SUNDAY THROUGH WEDNESDAY NIGHT

FAST MOVING FLOW ALOFT DURING MOST OF THE EXTENDED PERIOD WITH A
MID/UPPER LEVEL TROUGH PASSAGE EARLY SUNDAY. MEDIUM RANGE MODELS
GENERALLY HAVE CLOUDS AND MOISTURE EAST OF THE FORECAST AREA BY
SUNDAY AFTERNOON. IN FACT...FAIR WEATHER SHOULD PREVAIL WEST OF
THE DIVIDE ON SUNDAY. THINKING DOWNWARD FORCING BEHIND THIS TROUGH
TO RESULT IN BREEZY TO WINDY CONDITIONS SUNDAY AFTERNOON AND EVENING.

AFTER THIS TIME...FAST ZONAL FLOW OVER WYOMING WITH NEAR NORMAL
TEMPERATURES EXPECTED. MONDAY AND TUESDAY MORNINGS TO START OFF
RELATIVELY COOL. THERE LOOKS TO BE VERY LITTLE SUPPORT ALOFT FOR
PRECIPITATION WITH THIS PATTERN. WILL CALL IT MOSTLY DRY AND
BREEZY THROUGH WEDNESDAY. HOWEVER...CANNOT RULE OUT ISOLATED
SHOWERS OR THUNDERSTORMS EACH DAY ACROSS THE FORECAST AREA.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS WILL THEN PREVAIL ACROSS THE REGION THIS AFTERNOON
WITH NO SIGNIFICANT WINDS. A WEAK UPPER LEVEL DISTURBANCE WILL
SPREAD WDLY SCT -SHRA AND ISOLD -TSRA INTO THE NW MTNS...PRIMARILY
NORTH OF A KJAC-KCOD LINE...LATE THIS AFTERNOON AND EVENING WITH
THIS ACTIVITY SPREADING EAST AND A LITTLE SOUTH OVERNIGHT PRIMARILY
VCNTY AND NORTH OF KJAC-KWRL-KBYG LINE WITH CIGS FL120-150.

ANOTHER SYSTEM WILL MOVE IN FROM THE WEST DURING THE DAY FRIDAY WITH
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS DEVELOPING AND SPREAD EAST
ACROSS THE CENTRAL AND NORTHERN PART OF THE DISTRICT...MAINLY FROM
A KJAC...KPNA...KLND...KCPR LINE. VFR CONDITIONS WILL PREVAIL ACROSS
MOST OF THE AREA WITH JUST TEMPORARY MVFR VSBY OF 3-5 MILES IN ANY
HEAVIER SHOWERS OR THUNDERSTORMS.

.FIRE WEATHER...

WEAKENING SHOWERS AND THUNDERSTORMS EXPECTED OVER THE AREA THIS
MORNING...WITH BUILDING DRY WEST TO NORTHWEST FLOW. A FEW SHOWERS
WILL BE POSSIBLE ACROSS THE EXTREME NORTHWEST DURING THE EVENING AND
OVERNIGHT HOURS...WITH DRY CONDITIONS OTHERWISE. AN APPROACHING WAVE
OF LOW PRESSURE WILL TURN THE FLOW TO THE SOUTHWEST LATE FRIDAY AND
INTO SATURDAY. AHEAD OF THE TROUGH AXIS...CONDITIONS ACROSS SOUTHERN
WYOMING COULD BECOME BREEZY AND DRY...RAISING SOME FIRE WEATHER
CONCERNS. THE THREAT WILL BE SHORT LIVED...WITH SHOWERS AND
THUNDERSTORMS ANTICIPATED ACROSS THE AREA BY SATURDAY AFTERNOON.

&&

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

&&

$$

SHORT TERM...BRANHAM
LONG TERM...KPL
AVIATION...SKRBAC
FIRE WEATHER...BRANHAM






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