Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 200941
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
341 AM MDT SAT SEP 20 2014

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 245 AM MDT SAT SEP 20 2014

TODAY...LOOKS LIKE A QUIET DAY WITH NORTHWEST FLOW ALOFT. COOL
SURFACE HIGH PRESSURE WILL KEEP STABLE NORTH AND NORTHEAST WINDS AT
LOW LEVELS WITH NEGATIVE THETA-E ADVECTION. MAY SEE ISOLATED LATE
DAY SHOWERS AND THUNDERSTORMS NEAR THE SNOWY RANGE AND SOUTHERN
LARAMIE RANGE...THOUGH COVERAGE LOOKS MINIMAL.

TONIGHT...LOW LEVEL WINDS BECOME EASTERLY UPSLOPE AS THE SURFACE
HIGH MOVES OVER WESTERN SOUTH DAKOTA. DECENT 700 MB POSITIVE THETA-E
ADVECTION AND ADEQUATE LOW LEVEL MOISTURE WILL PRODUCE ISOLATED LATE
NIGHT SHOWERS FROM LARAMIE TO CHEYENNE TO SIDNEY.

SUNDAY...DIFFLUENT FLOW ALOFT ALONG WITH INCREASING LOW AND MID
LEVEL MOISTURE AND A THETA-E RIDGE SUGGEST ISOLATED TO SCATTERED
AFTERNOON SHOWERS AND THUNDERSTORMS SOUTH OF A RAWLINS TO TORRINGTON
LINE.

SUNDAY NIGHT...SHOWERS AND ISOLATED THUNDERSTORMS WILL INCREASE IN
COVERAGE WITH DIFFLUENT FLOW ALOFT AND INCREASING LOW AND MID LEVEL
MOISTURE.

MONDAY...SHORTWAVE TROUGH ALOFT MOVES OVERHEAD AND WITH ADEQUATE LOW
AND MID LEVEL MOISTURE...WE WILL SEE SCATTERED SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 340 AM MDT SAT SEP 20 2014

MODEL CONSENSUS APPROACH THE PREFERRED CHOICE. MID/UPPER LEVEL TROUGH
OVER THE CENTRAL ROCKY MOUNTAINS MONDAY NIGHT TRANSLATES EAST INTO
THE GREAT PLAINS TUESDAY. PACIFIC MOISTURE...SURFACE CONVERGENCE ALONG
A STALLED LEE TROUGH AND LARGE SCALE LIFT WILL RESULT IN SCATTERED
SHOWERS AND TSTORMS MONDAY NIGHT. DRIER NORTHWESTERLY FLOW ALOFT BEHIND
THE EXITING TROUGH AND UPSTREAM RIDGE TO THE WEST WILL BRING AN END
TO THE PRECIPITATION TUESDAY NIGHT. THE REMAINDER OF THE WEEK WILL
FEATURE DRY AND WARM WEATHER...WITH THURSDAY THE WARMEST DAY. SOUTHERLY
WINDS WILL BECOME BREEZY THURSDAY AND FRIDAY IN ADVANCE OF A PACIFIC
COLD FRONT. PRECIPITATION CHANCES INCREASE NEXT WEEKEND WITH THE
ARRIVAL OF A SLOW MOVING TROUGH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 245 AM MDT SAT SEP 20 2014

VFR CONDITIONS WILL PREVAIL THROUGHOUT THE FORECAST PERIOD. A
PRE-FRONTAL SURFACE TROUGH WILL EXIT THE AREA EARLY THIS MORNING
WITH WINDS SHIFTING TO NORTH- NORTHWEST. COOL FRONT WILL FOLLOW
LATER THIS MORNING WITH BREEZY EAST TO NORTHEAST WINDS INTO THE
AFTERNOON. OROGRAPHIC LIFT AND MARGINAL MOISTURE/INSTABILITY MAY
TRIGGER ISOLATED SHRA/TSRA OVER THE SNOWY...SIERRA MADRE AND SOUTH
LARAMIE RANGES THIS AFTERNOON...BUT SHOULD NOT IMPACT NEIGHBORING
AERODROMES LIKE SARATOGA AND LARAMIE.

&&

.FIRE WEATHER...
ISSUED AT 245 AM MDT SAT SEP 20 2014

MINIMAL CONCERNS BASED ON PROJECTED HUMIDITIES AND WINDS.

&&

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

$$

SHORT TERM...RUBIN
LONG TERM...JAMSKI
AVIATION...JAMSKI
FIRE WEATHER...RUBIN



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