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000
FXUS65 KCYS 270832
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
232 AM MDT SUN JUL 27 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 230 AM MDT SUN JUL 27 2014

TODAY...HEIGHTS ALOFT INCREASE SLIGHTLY AS RIDGING BECOMES MORE
PRONOUNCED ACROSS WESTERN WYOMING. SURFACE HIGH PRESSURE OVER THE
PLAINS STATES KEEPS MOIST EASTERLY LOW LEVEL WINDS ACROSS OUR
COUNTIES. BY THIS AFTERNOON...A LOW AND MID LEVEL THETA-E RIDGE AXIS
DEVELOPS FROM CASPER TO LARAMIE...AND THUS EXPECT ISOLATED TO
LOCALLY SCATTERED THUNDERSTORMS TO ERUPT THIS AFTERNOON OVER AND
NEAR THE SNOWY AND SIERRA MADRE RANGES...DRY ELSEWHERE.

TONIGHT...QUIET AND COOL OVERNIGHT WITH LOSS OF DAYTIME HEATING.

MONDAY...RIDGING ALOFT NOT QUITE AS PRONOUNCED AND WITH A LOW AND
MID LEVEL THETA-E RIDGE AXIS DEVELOPING ACROSS SOUTHEAST WYOMING AND
POSITIVE THETA-E ADVECTION...THUNDERSTORM COVERAGE IN THE AFTERNOON
AND EVENING WILL INCREASE ALONG AND WEST OF INTERSTATE 25.

MONDAY NIGHT...MAY SEE AT LEAST ISOLATED SHOWERS AND THUNDERSTORMS
CONTINUE ALL NIGHT AS LOW AND MID LEVEL MOISTURE REMAINS WITH A WEAK
SHORTWAVE TROUGH ALOFT MOVING OVERHEAD IN NORTHWEST FLOW ALOFT.

TUESDAY...CONTINUES TO LOOK LIKE A DAY WITH SCATTERED TO NUMEROUS
SHOWERS AND ISOLATED THUNDERSTORMS...ESPECIALLY SOUTH OF A RAWLINS
TO SCOTTSBLUFF LINE WHERE THE ATMOSPHERE WILL BE THE MOST MOIST.
COMPROMISED ON HIGH TEMPERATURES...THOUGH THE COOLER NAM MOS HIGHS
COULD BE CLOSEST IF SHOWERS PERSIST MOST OF THE DAY.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 230 AM MDT SUN JUL 27 2014

A LARGE SCALE BLOCKING PATTERN WILL REMAIN IN PLACE ACROSS THE
CONUS THROUGH THE EXTENDED FCST PERIOD. STRONG UPPER-LEVEL RIDGING
OVER THE WESTERN STATES WITH A PERSISTENT TROUGH ANCHORED ALONG
THE EASTERN SEABOARD WILL KEEP THE CENTRAL ROCKIES UNDER ACTIVE
NORTHWESTERLY FLOW ALOFT THROUGH MID TO LATE WEEK. MEDIUM RANGE
MODEL GUIDANCE SHOWS THE BEST MONSOONAL MOISTURE TO BE IN THE WED
TO THU TIME FRAME...FAVORABLY ALIGNED WITH INCREASING MOIST LLVL
UPSLOPE WITH A COLD FRONTAL PASSAGE. THE GFS IS CONSIDERABLY DRIER
THAN THE ECMWF WHICH SHOWS 36 HOUR QPF VALUES WELL IN EXCESS OF 2
INCHES OVER THE SOUTH LARAMIE RANGE. THIS IS A FAVORABLE PATTERN FOR
A WIDESPREAD PCPN EVENT WITH THE POTENTIAL FOR TRAINING CONVECTION.
WPC PRECIP OUTLOOKS ALSO NAIL DOWN THE CO FRONT RANGE INTO SOUTHEAST
WY FOR EXCESSIVE RAINFALL THROUGH MID WEEK. AS SUCH...THIS WILL
DEFINITELY NEED TO BE WATCHED OVER THE NEXT FEW DAYS. TRENDED
HIGHER WITH POPS THIS FCST PACKAGE...AND CONTINUED TO GO SEVERAL
DEGREES BELOW CONSENSUS MOS FOR HIGHS ON WED GIVEN H7 TEMPS BETWEEN
8 AND 10 C AND EXPECTED CLOUDS/PCPN. MOISTURE APPEARS TO BECOME
MORE LIMITED LATE IN THE WEEK...AND SUBSIDENCE STRENGTHENS AS THE
RIDGE SHIFTS SLOWLY EASTWARD. CONVECTIVE CHANCES BEYOND WED SHOULD
BE CONFINED TO THE HIGHER TERRAIN. OVERALL TEMPS SHOULD BE QUITE
SEASONAL.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1102 PM MDT SAT JUL 26 2014

CLEAR SKIES FOR MUCH OF THE FORECAST AREA TONIGHT BUT WILL START
TO SEE SOME STRATUS DEVELOP LATE TONIGHT. COULD SEE SOME IFR CIGS
AROUND CYS AND TOWARDS THE SOUTHERN LARAMIE RANGE AROUND SUNRISE
SUNDAY MORNING. CIGS SHOULD BECOME MVFR TO VFR BY LATER IN THE
MORNING AS THE STRATUS DECK RISES. ISOLATED THUNDERSTORMS POSSIBLE
MAINLY ALONG AND WEST OF THE SOUTHERN LARAMIE RANGE SUNDAY
AFTERNOON. GUSTY WINDS EXPECTED NEAR SOME SHOWERS AND
THUNDERSTORMS.

&&

.FIRE WEATHER...
ISSUED AT 230 AM MDT SUN JUL 27 2014

HUMIDITIES WILL CONTINUE TO SLOWLY INCREASE THROUGH TUESDAY AS
LOW LEVEL MOISTURE INCREASES AND CLOUDS AND PRECIPITATION COVERAGE
INCREASE.

&&

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

$$

SHORT TERM...RUBIN
LONG TERM...HAMMER
AVIATION...SML
FIRE WEATHER...RUBIN