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000
FXUS65 KCYS 182356
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
556 PM MDT FRI APR 18 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 212 PM MDT FRI APR 18 2014

MAIN QUESTION THIS EVENING IS IF CONVECTION CAN ACTUALLY BE
SUSTAINED LATER THIS AFTERNOON/EARLY EVENING. THE CONVECTION WHICH
HAS DEVELOPED HAS QUICKLY DIED OFF AFTER FORMATION...SO BEGINNING TO
WONDER IF SHOWERS AND THUNDERSTORMS ARE WORTH MENTIONING AT THIS
POINT. CIRRUS DECK TODAY WAS LIKELY JUST ENOUGH TO INHIBIT
STRONGER SURFACE WARMING AND DEEPER CONVECTION DEVELOPMENT. ALSO
THE LOW AND MID LEVEL ARE ON THE DRY SIDE. VERY WELL MAY NEED TO
TAKE MOST SHOWER AND THUNDERSTORM MENTION OUT OF THE FORECAST IN
THE NEXT FEW HOURS IF NOTHING DEVELOPS.

OTHERWISE FOR TONIGHT INCREASING HIGH AND MID CLOUDS WITH MOISTURE
LIFTING OUT OF THE SOUTHWEST CONUS INTO SOUTHEAST WYOMING AND
NEBRASKA PANHANDLE...WHILE A COLD FRONT WILL DROP SOUTHWARD OVER
EASTERN PORTIONS OF THE FORECAST AREA. COULD SEE A FEW SHOWERS IN
THE SNOWY AND SIERRA MADRE RANGES LATE TONIGHT BUT THAT WOULD BE
ABOUT IT. SLIGHTLY BETTER CHANCE FOR A FEW SHOWERS AND
THUNDERSTORMS TOMORROW AFTERNOON...MAINLY OVER THE SOUTHERN CWA AS
NORTHERN FRINGES OF AN UPPER LEVEL LOW LIFT INTO THE AREA. SEVERE
THUNDERSTORMS ARE NOT EXPECTED.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 315 PM MDT FRI APR 18 2014

MODELS IN REASONABLE AGREEMENT THROUGH NEXT WEEK. AN UPPER LEVEL
RIDGE WILL SETTLE OVER THE AREA ON MONDAY AFTER A WEAK UPPER LEVEL
DISTURBANCE MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKY MOUNTAINS.
A WEAK BACK DOOR COLD FRONT WILL DRIFT SOUTHWARD ACROSS THE HIGH
PLAINS SUNDAY NIGHT AND MONDAY RESULTING IN SLIGHTLY COOLER
TEMPERATURES FOR THE DAY. TEMPERATURES WILL STILL BE NEAR OR
SLIGHTLY ABOVE NORMAL AND GENERALLY IN THE 60S TO NEAR 70.
MEANWHILE...A STRONG STORM SYSTEM WILL MOVE INTO THE PACIFIC
COASTLINE WITH THE MAIN UPPER LEVEL LOW LOCATED SOMEWHERE ACROSS
THE PACIFIC NORTHWEST TUESDAY NIGHT. THIS STORM WILL BEGIN TO
IMPACT THE FORECAST AREA ON TUESDAY WITH GUSTY WINDS...BUT
TEMPERATURES AHEAD OF THE PACIFIC COLD FRONT WILL INCREASE INTO
THE 70S ACROSS MOST AREAS AND NEAR 80 ACROSS PORTIONS OF THE
NE PANHANDLE.

FOR WEDNESDAY...MODELS SHOW THE DEEP UPPER LEVEL LOW MOVING
ACROSS THE NORTHERN AND CENTRAL ROCKY MOUNTAINS. THE EXACT
POSITION AND MOVEMENT OF THIS STORM IS STILL UNCERTAIN...BUT IT IS
TRENDING NORTHWARD AND SHOWS THE SYSTEM GRADUALLY BECOMING AN OPEN
WAVE. THE GFS...GEM AND ECMWF SHOW THE STORM NORTH OF THE
FORECAST AREA. ENSEMBLE FORECASTS SHOW THE SAME...SO IT SEEMS
UNLIKELY THERE WILL BE ANY TREND SOUTHWARD AND MORE SIGNIFICANT
IMPACTS FOR THE FORECAST AREA. HOWEVER...THE SYSTEM IS SEVERAL
DAYS AWAY FROM MOVING ONSHORE SO WILL HAVE A BETTER IDEA SOMETIME
LATE THIS WEEKEND AND EARLY NEXT WEEK. FOR NOW...KEPT POP BETWEEN
15 TO 30 PERCENT...HIGHEST FURTHER NORTH AND IN THE MOUNTAINS
WEDNESDAY NIGHT THROUGH THURSDAY. WEDNESDAY WILL BE TRICKY BECAUSE
OF FIRE WEATHER CONCERNS...UNLESS THE SYSTEM DIGS SOUTHWARD WHERE
MUCH COLDER TEMPERATURES...WIND...AND PRECIPITATION WILL BE THE
MAIN CONCERN. TRENDED DRIER FOR NOW GIVEN MODEL CONSENSUS. LOWERED
TEMPERATURES THURSDAY AND FRIDAY AS THE PACIFIC COLD FRONT MOVES
ACROSS THE REGION...WITH HIGHS AND LOWS NEAR OR SLIGHTLY BELOW
NORMAL.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY AFTERNOON)
ISSUED AT 533 PM MDT FRI APR 18 2014
LATEST RADAR LOOP WAS SHOWING VIRGA SHOWERS TRYING TO GET GOING TO
THE EAST OF CHEYENNE. MAY SEE A FEW WIND GUSTS UNDERNEATH THESE
SHOWERS THIS EVENING. OTHERWISE...LOW PRESSURE IN WESTERN SOUTH
DAKOTA WITH A TRAILING FRONTAL BOUNDARY EXTENDING TO SOUTHWEST
THROUGH CONVERSE COUNTY SHOULD CONTINUE TO PUSH SOUTHEAST THIS
EVENING. THIS BOUNDARY SHOULD MOVE THROUGH CDR AND LAR TAF SITES
BY 03Z...CYS...AIA...BFF BETWEEN 04Z AND 07Z AND SNY BY 10Z. NOT
EXPECTING MUCH MORE THAN A WIND SHIFT BEHIND THIS BOUNDARY.
OTHERWISE...WE ARE LOOKING MORE INSTABILITY SHOWERS AND
THUNDERSTORMS DEVELOPING TOMORROW AFTERNOON MAINLY ACROSS
SOUTHEAST WYOMING.


&&

.FIRE WEATHER...
ISSUED AT 212 PM MDT FRI APR 18 2014

NEAR CRITICAL FIRE WEATHER CONDITIONS OVER FAR SOUTHEAST WYOMING
AND THE NEBRASKA PANHANDLE WILL IMPROVE THIS EVENING AS HUMIDITY
INCREASES. A COLD FRONT ASSOCIATED WITH THE LOW PRESSURE WILL MOVE
INTO SOUTHEAST WYOMING LATE TONIGHT...WITH WINDS SHIFTING TO THE
NORTHEAST AND TEMPERATURES COOLER FOR TOMORROW. INCREASING
CHANCES FOR WETTING RAINS AND MOUNTAIN SNOW SATURDAY NIGHT INTO
SUNDAY FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE AS LOW
PRESSURE TRACKS ACROSS NORTHERN COLORADO.

&&

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

$$

SHORT TERM...SML
LONG TERM...TJT
AVIATION...REC/RAE
FIRE WEATHER...GARMON/SML