Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 280552
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1152 PM MDT THU AUG 27 2015

.UPDATE...
ISSUED AT 904 PM MDT THU AUG 27 2015

NO BIG CHANGES TO THE OVERNIGHT FORECAST BUT DID EXPANDED SHOWERS
AND THUNDERSTORMS A LITTLE LATER INTO THIS EVENING. BASED ON WATER
VAPOR THERE DOES APPEAR TO BE A WEAK DISTURBANCE MOVING ACROSS
SOUTHEAST WYOMING AT THIS TIME. THERE IS LIKELY JUST ENOUGH
FORCING TO KEEP CONVECTION GOING A FEW MORE HOURS. MOST ALL
ACTIVITY SHOULD END BY MIDNIGHT WITH SKIES BEGINNING TO CLEAR.
OVERALL IT WILL BE A NICE NIGHT WITH LIGHT WINDS AND LOW
TEMPERATURES MAINLY IN THE 50S.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 213 PM MDT THU AUG 27 2015

CURRENTLY ISOLATED SHOWERS AND THUNDERSTORMS WILL LINGER INTO
THIS EVENING WITH PLENTY OF MOISTURE IN THE MID LEVELS. RAIN
CHANCES SHOULD DIMINISH INTO TONIGHT AS LOW TO MID LEVELS DRY OUT
WITH THE PASSAGE OF A SHORTWAVE TROUGH. AN UPPER LEVEL RIDGE WILL
DEVELOP TOMORROW WITH HIGH TEMPERATURES INTO THE 80S OVER THE
EASTERN PLAINS AND PANHANDLE... AND 70S IN THE MOUNTAINS.
THUNDERSTORMS DEVELOPMENT WILL BE MINIMAL FRIDAY... THE SNOWY AND
SIERRA MADRES COULD SEE A FEW POP UP. A SHIFT TO SOUTHWESTERLY
FLOW AND CONTINUED BUILDING OF THE UPPER LEVEL RIDGE INTO SATURDAY
WILL KEEP CHANCES OF THUNDERSTORMS LOW.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 213 PM MDT THU AUG 27 2015

THE LARGE SCALE PATTERN THROUGH MUCH OF THE EXTENDED PERIOD WILL BE
DOMINATED BY MOIST SOUTHWEST FLOW ALOFT AHEAD OF A DEEPENING UPPER-
LEVEL TROUGH OVER THE PACIFIC NW. A SERIES OF MID LEVEL DISTURBANCES
WILL TRAVERSE THE FLOW THROUGH MID WEEK...PROVIDING FOCUS FOR DAILY
CHANCES FOR CONVECTION ACROSS THE CWA. WHILE CONFIDENCE IS HIGH WITH
THE OVERALL PATTERN...THE EXACT TIMING/PLACEMENT OF INDIVIDUAL WAVES
REMAINS UNKNOWN. HAVE MAINTAINED ISOLATED TO WIDELY SCATTERED POPS
EACH AFTERNOON...HIGHEST OVER THE MOUNTAINS. ORGANIZED THREATS FOR
SEVERE CONVECTION SHOULD BE LOW WITH GFS CAPES LESS THAN 1000 J/KG.
SUNDAY SHOULD BE ONE OF THE WARMEST DAYS OF THE PERIOD AS THE RIDGE
AXIS STARTING TO SHIFT EAST. GFS/ECMWF/GEM 700 MILLIBAR TEMPERATURES
AROUND +15 DEG C WOULD SUPPORT WIDESPREAD 90S OVER THE PLAINS...BUT
INCREASING H7-H3 MOISTURE COULD YIELD ENOUGH CLOUD COVER TO KEEP IT
JUST A BIT COOLER. THAT SAID...UNDERCUT GUIDANCE BY A DEGREE OR TWO
ON SUNDAY. TEMPERATURES THROUGH THE REST OF THE PERIOD ARE EXPECTED
TO STAY RIGHT AROUND SEASONAL NORMS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1152 PM MDT THU AUG 27 2015

A LINE OF SHOWERS AND THUNDERSTORMS LOOKS TO IMPACT KCYS SHORTLY
AFTER 06Z BRINGING GUSTY WINDS AND POSSIBLY MVFR VSBYS IN MODERATE
RAIN. A FEW SHOWERS CONTINUE AS WELL FURTHER WEST AND COULD AFFECT
KLAR AND KRWL OVER THE NEXT FEW HOURS. ONCE THIS ACTIVITY
DISSIPATES OVERNIGHT...THE REMAINDER OF THE PERIOD SHOULD REMAIN
FAIRLY QUIET. NORTH WINDS GUSTING TO 20 KTS ARE EXPECTED FROM KAIA
TO KSNY ON FRIDAY AFTERNOON...OTHERWISE LIGHT WINDS AND MOSTLY
CLEAR SKIES WILL PREVAIL.

&&

.FIRE WEATHER...
ISSUED AT 213 PM MDT THU AUG 27 2015

MINIMAL FIRE WEATHER CONCERNS THROUGH FRIDAY NIGHT
DUE TO MODERATE DAYTIME HUMIDITIES AND RELATIVELY LIGHT WINDS
THROUGH FRIDAY AFTERNOON. TEMPERATURES WILL INCREASE ON SATURDAY AS
A RIDGE OF HIGH PRESSURE STRENGTHENS OVER THE AREA. RELATIVE
HUMIDITIES ARE EXPECTED TO LOWER TO NEAR CRITICAL LEVELS...BUT WINDS
ARE QUESTIONABLE AT THIS TIME. DO BELIEVE A FEW LOCATIONS WILL SEE
WIND GUSTS OVER 25 MPH...BUT NOT VERY CONFIDENT ON THE LOCATION OR
IF IT WILL BE WIDESPREAD ENOUGH. THE MOST FAVORABLE AREA APPEARS TO
BE CARBON COUNTY...BUT LIVE FUELS ARE NOT CRITICAL AT THIS TIME FOR
PORTIONS OF THAT AREA. EAST CENTRAL WYOMING (ZONE 301) IS ALSO
SOMEWHAT FAVORABLE...BUT BASED ON MODEL SOUNDINGS WINDS MAY STRUGGLE
TO REACH CRITERIA WITH WIND SPEEDS ACTUALLY DECREASING WITH HEIGHT.

&&

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

$$

UPDATE...SML
SHORT TERM...KC
LONG TERM...CLH
AVIATION...RJM
FIRE WEATHER...TJT



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