Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 052204
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
404 PM MDT TUE MAY 5 2015

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 330 PM MDT TUE MAY 5 2015

THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE TIMING OF THE
PRECIPITATION MOVING INTO THE AREA TONIGHT.

TONIGHT-WEDNESDAY:
LATEST RADAR LOOP WAS SHOWING THE LEADING EDGE OF THE SHOWERS
BEGINNING TO MOVE INTO SOUTHEAST WYOMING. THESE SHOWERS WILL
CONTINUE TO SPREAD NORTHWEST DURING THE NEXT FEW HOURS. IN THE
MEANTIME...THE SCATTERED SHOWERS AND THUNDERSTORMS WERE MAINLY
FOCUSED IN THE MOUNTAINS WITH THIS ACTIVITY  AFTER SUNSET. AS
THIS BATCH OF RAIN IN SOUTHEAST WYOMING MOVES INTO THE PICTURE
THIS EVENING...WE WILL ALSO SEE HEIGHT FALLS IN RESPONSE TO THE
UPPER LEVEL TROF MOVING INTO THE PACIFIC NORTHWEST. THESE TWO
FACTORS COMBINED WITH SURFACE HIGH PRESSURE DEVELOPING OVER
SOUTHERN MONTANA WILL CAUSE A LOW LEVEL FRONTAL BOUNDARY TO
INTENSIFY OVER NORTHERN WYOMING. AS THIS FRONTAL BOUNDARY PUSHES
THROUGH...WE WILL SEE THE POTENTIAL FOR RAINFALL TO DEVELOP OVER
NORTHWEST WYOMING OVERNIGHT AND SPREAD EAST INTO THE PLAINS
WEDNESDAY MORNING. THIS WILL BRING WIDESPREAD RAINFALL TO MUCH OF
THE REGION OVERNIGHT WITH 1 TO 2 INCHES OF SNOW ACCUMULATION IN
THE MOUNTAINS. THE BULK OF THE RAIN WILL MOVE OUT OF THE PICTURE
WEDNESDAY AFTERNOON AND EVENING WITH LEFTOVER SCATTERED SHOWERS IN
NATRONA COUNTY DURING THE AFTERNOON DUE TO GOOD UPSLOPE FLOW. THE
REST OF THE AREA SHOULD SEE THE RAINFALL DIMINISHING.



.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 PM MDT TUE MAY 5 2015

WE WILL CONTINUE TO BE AN UNSETTLED WEATHER PATTERN THROUGH THE
REMAINDER OF THE WEEKEND AS THE UPPER LEVEL DISTURBANCE MOVES INTO
THE GREAT BASIN AND SHIFTS SLOWLY EAST THROUGH COLORADO INTO
WYOMING. WE WILL KEEP CHANCES OF SHOWERS AND THUNDERSTORMS GOING
THROUGH THE WEEKEND DUE TO GOOD UPPER LEVEL DIFFLUENCE IN PLACE.
SHOULD SEE SOME IMPROVEMENT CONDITIONS EARLY NEXT WEEK AS AN UPPER
LEVEL RIDGE BUILDS OVER THE AREA WITH CORRESPONDING SURFACE HIGH
PRESSURE. ALONG WITH THAT WILL COME MILD TEMPERATURES AND DRIER
CONDITIONS WITH ONLY A FEW SCATTERED SHOWERS AND THUNDERSTORMS IN
THE MOUNTAINS.

&&

.AVIATION.../18Z TAF ISSUANCE/

THE MAIN CONCERN WITH THIS TAF ISSUANCE IS THE TIMING OF WHEN THE
CLUSTER OF SHOWERS AND THUNDERSTORMS WILL MOVE INTO THE AREA.
LATEST WATER VAPOR LOOP WAS SHOWING THE UPPER LEVEL LOW SPINNING
OVER NORTHWEST NEW MEXICO. THIS UPPER LEVEL LOW IS DRAWING IN
COPIOUS AMOUNTS OF MOISTURE FROM THE SOUTHEAST WITH RAINFALL
OCCURRING ACROSS MUCH OF NORTHEAST COLORADO. THIS CLUSTER OF
CONVECTION WILL GRADUALLY SPILL INTO THE AREA THIS EVENING. IN
ADDITION...SURFACE HIGH PRESSURE WILL BEGIN TO BUILD INTO THE AREA
FROM SOUTHERN MONTANA. THIS WILL INCREASE LOW LEVEL FRONTOGENISIS
ACROSS NORTHERN WYOMING OVERNIGHT AND MAY YIELD FOR INCREASE
CHANCES OF SHOWERS AND LOWER MVFR CEILINGS ACROSS THE NORTHERN
TAF SITES INCLUDING KWRL...KCOD...KCPR AND KLND TOWARDS DAYBREAK.


&&

.FIRE WEATHER...
ISSUED AT 330 PM MDT TUE MAY 5 2015

THE POTENTIAL FOR WIDESPREAD FIRE ACTIVITY WILL BE SUPPRESSED BY
WETTING RAINS THROUGH THE WEEKEND.

&&

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

$$

SHORT TERM...COX
LONG TERM...COX
AVIATION...TEAM RIVERTON
FIRE WEATHER...COX


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