Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 182007
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
107 PM MST TUE NOV 18 2014

.SHORT TERM...TONIGHT THROUGH WEDNESDAY

NORTH NORTHWEST FLOW ALOFT WILL CONTINUE TO BRING AREAS OF MID AND
UPPER LEVEL CLOUD COVER TO WESTERN AND CENTRAL WYOMING.  AREAS IMPACTED
BY STRONG INVERSIONS ARE GRADUALLY DECREASING WITH STRONG TEMPERATURE
AND WIND GRADIENTS EXISTING BOTH HORIZONTALLY AND VERTICALLY. THE COLDER
TRAPPED AREAS WILL CONTINUE TO SEE AREAS OF LOW STRATUS CLOUDS AND FOG
WITH GENERALLY LIGHT WINDS.  THE MIXED AREAS WILL BE 20 TO 30
DEGREES WARMER THAN THE TRAPPED VALLEYS AND BASINS AT TIMES...WITH
SIGNIFICANTLY LOWER RELATIVE HUMIDITY AND STRONG GUSTY WINDS. THE
NORTHERN MOUNTAINS CAN EXPECT SOME VERY LIGHT SNOW THIS EVENING...
OTHERWISE DRY CONDITIONS WILL PREVAIL THROUGH WEDNESDAY.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

AN AMPLIFYING RIDGE OF HIGH PRESSURE WILL START OFF THE FORECAST
PERIOD. A WAVE OF LOW PRESSURE WILL MOVE EAST OVER THE PACIFIC
COASTLINE WEDNESDAY...AND MODELS CONTINUE TO INDICATE THAT THIS
SYSTEM WILL SPLIT AS IT ADVANCES TOWARDS THE INTERMOUNTAIN WEST.
THE NORTHERN PORTION OF THIS SYSTEM MAY BRING WEAK AMOUNTS OF
MOISTURE FOR AREAS WEST OF THE CONTINENTAL DIVIDE BY LATE WEDNESDAY
NIGHT AND INTO THURSDAY MORNING. THESE SHOWERS ARE NOT EXPECTED TO
BE SIGNIFICANT.

A STRONGER PUSH OF MOISTURE WILL MOVE OVER THE INTERMOUNTAIN WEST ON
SATURDAY...WITH INCREASING SHOWER ACTIVITY EXPECTED OVER THE WESTERN
MOUNTAINS AND VALLEYS. THE WAVE OF LOW PRESSURE ASSOCIATED WITH THIS
SYSTEM WILL CONTINUE ITS EASTWARD PROGRESSION...AND WILL INCREASE
COVERAGE ACROSS WESTERN WYOMING...WITH SHOWERS SPILLING OVER TO THE
EAST SIDE OF THE DIVIDE BY SATURDAY EVENING.

SHOWERS WILL CONTINUE EVEN AS THIS SYSTEM MOVES EAST OF THE FORECAST
AREA ON SUNDAY. A MOIST NORTHWEST FLOW WILL DEVELOP OVER THE AREA
HIGH PRESSURE ATTEMPTS TO BUILD OVER THE WESTERN HALF OF THE UNITED
STATES. A BRIEF REPRIEVE FROM SHOWERS MAY BE FOUND LATE MONDAY...BUT
WILL BE SHORT LIVED AS ANOTHER...POTENTIALLY POTENT SLUG OF MOISTURE
MOVES INTO THE WEST BY LATE MONDAY NIGHT. THIS MOISTURE WILL AGAIN
SPREAD ACROSS THE FORECAST AREA THROUGH TUESDAY.

A GENERAL WARMING TREND IS ANTICIPATED THROUGH SATURDAY...WITH A
RETURN OF COLDER AIR EXPECTED SUNDAY AND INTO THE EARLY PORTION OF
THE WORK WEEK.

&&

.AVIATION.../00Z ISSUANCE/

VFR CONDITIONS WILL PREVAIL THROUGH 00Z THURSDAY AT THE AIRPORTS WITH
THE EXCEPTION OF KJAC AND KAFO WHERE LOW STRATUS AND AREAS OF FOG
WILL PERSIST IN THE VICINITY WITH PERIODS OF MVFR TO IFR CEILINGS
AND VISIBILITIES.

LOW LYING AREAS IN THE VALLEYS AND BASINS OF WESTERN AND CENTRAL
WYOMING WILL ALSO SEE AREAS OF LOW STRATUS AND PATCHY FOG...
ESPECIALLY ALONG RIVERS AND RESERVOIRS. BREEZY TO WINDY CONDITIONS
WILL OCCUR TODAY INTO THIS EVENING IN THE FAVORED WIND LOCATIONS...
INCLUDING VICINITY OF KCOD...AND FROM VICINITY OF KCPR TO KRKS.

&&

.FIRE WEATHER...

NORTH NORTHWEST FLOW ALOFT WILL CONTINUE TO BRING AREAS OF MID AND
UPPER LEVEL CLOUD COVER TO WESTERN AND CENTRAL WYOMING.  AREAS IMPACTED
BY STRONG INVERSIONS ARE GRADUALLY DECREASING WITH STRONG TEMPERATURE
AND WIND GRADIENTS EXISTING BOTH HORIZONTALLY AND VERTICALLY. THE COLDER
TRAPPED AREAS WILL CONTINUE TO SEE AREAS OF LOW STRATUS CLOUDS AND FOG
WITH GENERALLY LIGHT WINDS AND VERY LOW MIXING HEIGHTS AND POOR
SMOKE DISPERSAL. THE MIXED AREAS WILL BE 20 TO 30 DEGREES WARMER THAN
THE TRAPPED VALLEYS AND BASINS AT TIMES WITH SIGNIFICANTLY LOWER
RELATIVE HUMIDITY AND STRONG GUSTY WINDS. THE NORTHERN MOUNTAINS
CAN EXPECT SOME VERY LIGHT SNOW... OTHERWISE DRY CONDITIONS WILL
PREVAIL.

&&

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

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER








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