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000
FXUS65 KCYS 302316
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
516 PM MDT WED JUL 30 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 335 PM MDT WED JUL 30 2014

CURRENT IR SATELLITE LOOP AND OBSERVATIONS SHOW THE STUBBORN UPPER
LEVEL DISTURBANCE REMAINING NEARLY STATIONARY ACROSS SOUTHWEST
WYOMING. MODELS ARE NOW SHOWING THIS FEATURE WEAKENING AND
DISSIPATING NEAR THE COLORADO BORDER TONIGHT...INSTEAD OF MOVING
SOUTHEAST ACROSS THE AREA. THIS IS THE REASON WHY CONDITIONS HAVE
STRUGGLED TO IMPROVE TODAY ACROSS MOST OF THE SOUTHERN HALF OF THE
FORECAST AREA ALONG THE I80 CORRIDOR. EXPECT OFF AND ON RAIN
SHOWERS TO CONTINUE INTO THIS EVENING...GRADUALLY DIMINISHING IN
COVERAGE. THERE HAVE BEEN A FEW LIGHTNING STRIKES...SO KEPT
TSTORMS IN THE FORECAST FOR THIS AFTERNOON. RAINFALL WILL LIKELY
END BY MIDNIGHT ACROSS THE WHOLE FORECAST AREA WITH JUST CLOUDY
AND VERY COOL CONDITIONS OVER THE AREA. WOULD NOT BE SURPRISED IF
A FEW OF THE MORE SHELTERED VALLEYS LOCATIONS SEE LOW
TEMPERATURES IN THE UPPER 30S BY THURSDAY MORNING. THE ONLY OTHER
MINOR CONCERN TONIGHT IS FOG...ESPECIALLY WEST OF THE LARAMIE
RANGE.

MODELS INDICATE DRIER AIR MOVING INTO THE REGION FOR THURSDAY AND
FRIDAY...LIMITING CONVECTIVE POTENTIAL ACROSS MOST OF THE AREA.
NORTHWEST FLOW ALOFT WILL KEEP TEMPERATURES ON THE COOL SIDE AND
GENERALLY 5 TO 10 DEGREES BELOW NORMAL. IT WILL BE PLEASANT DURING
THE DAY HOWEVER WITH HIGHS IN THE MID 70S TO MID 80S...WARMEST
OVER EAST CENTRAL WYOMING TO NORTHWEST NEBRASKA. IT WILL REMAIN
COOL AT NIGHT WITH LOWS IN THE 40S OR POSSIBLY UPPER 30S ACROSS
THE HIGH VALLEYS OF SOUTHEAST WYOMING. KEPT A CHANCE OF
THUNDERSTORMS IN THE FORECAST FOR LOCATIONS ALONG AND WEST OF THE
LARAMIE RANGE. ACTIVITY SHOULD BE LIMITED DUE TO THE AMOUNT OF DRY
AIR MOVING INTO THE AREA. FURTHER EAST..THIS DRY AIR WILL MAINLY
BE ALOFT WITH DEWPOINTS REMAINING IN THE 40S AND 50S EAST OF THE
LARAMIE RANGE. THIS DRY AIR ALONG WITH A TEMPERATURE INVERSION
ABOVE 600MB WILL LIMIT ANY CONVECTION THAT DOES DEVELOP ACROSS THE
PLAINS.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)

MEDIUM RANGE MODELS CONTINUE TO SHOW THE UPPER RIDGE MAINTAIN A
STRONG HOLD OVER THE WESTERN CONUS THRU THE WEEKEND AND INTO EARLY
NEXT WEEK. MOSTLY DRY...NORTHWEST FLOW WILL BE OVER THE FORECAST
AREA THROUGH THIS TIME WITH PERHAPS ENOUGH MOISTURE AVAILABLE FOR A
FEW WEAK THUNDERSTORMS OVER THE MOUNTAINS SATURDAY AND SUNDAY
AFTERNOONS. TEMPERATURES WILL RISE BACK TO MORE NORMAL VALUES FOR
THIS TIME OF YEAR BY SUNDAY AS H7 TEMPS INCREASE TO BETWEEN 11 AND
17C. ANOTHER PUSH OF SUBTROPICAL ENERGY AND MOISTURE WILL RIDE UP
THE WESTERN PERIPHERY OF THE RIDGE AND OVER THE FORECAST AREA MONDAY
AND TUESDAY. WITH WARMER TEMPS AND PWATS FORECAST TO EXCEED ONE
INCH...LOOKING AT A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS
THROUGH THIS TIME. STEERING FLOW WILL ONCE AGAIN BE WEAK SO THE
POTENTIAL FOR FLOODING WILL INCREASE AS WELL. A COLD FRONT LOOKS TO
MOVE THROUGH THE FORECAST AREA ON TUESDAY WHICH WILL BRING SLIGHTLY
COOLER CONDITIONS FOR TUESDAY AND WEDNESDAY WITH CONTINUED CHANCES
FOR SHOWERS AND STORMS ON WEDNESDAY IN THE UPSLOPE REGIME.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY AFTERNOON)
ISSUED AT 512 PM MDT WED JUL 30 2014

LOTS OF LOW LEVEL MOISTURE AROUND THE SOUTH LARAMIE RANGE. COULD
SEE SOME IFR FOG AND/OR STRATUS HERE AT KCYS AND KLAR. SREF AND
LATEST HRRR FORECAST HINTING AT THIS FOR BOTH AIRPORTS. WENT AHEAD
AND BROUGHT MVFR CONDITIONS IN AT 04Z AND THEN IFR AROUND 07Z.
CONFIDENCE IS NOT HIGH ON THE TIMING OF THE MVFR/IFR. OUTSIDE THE
SOUTH LARAMIE RANGE...CONDITIONS SHOULD BE VFR.

&&

.FIRE WEATHER...
ISSUED AT 230 PM MDT WED JUL 30 2014

NO FIRE WEATHER CONCERNS THROUGH THIS WEEKEND DUE TO THE RECENT
WIDESPREAD WETTING RAINS...HIGH HUMIDITIES...AND LOWER THAN NORMAL
TEMPERATURES. WINDS WILL ALSO BE LIGHT AS WELL ACROSS THE AREA.
ISOLATED THUNDERSTORMS ARE EXPECTED OVER THE MOUNTAINS THROUGH
SATURDAY...WITH A MORE WIDESPREAD THREAT OF RAIN AND THUNDERSTORMS
NEXT WEEK AS ANOTHER SURGE OF MONSOON MOISTURE MOVES ACROSS THE
REGION.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...TJT
LONG TERM...RJM
AVIATION...CLAYCOMB
FIRE WEATHER...TJT