Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 281146
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
546 AM MDT FRI AUG 28 2015

.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 344 AM MDT FRI AUG 28 2015

TODAY...WSR-88D REFLECTIVITY LOOPS SHOWING SHOWERS NOW SLOWLY
COMING TO AN END ACROSS SOUTHEAST WYOMING. LOOKS LIKE A DRY AND
MILD DAY WITH RIDGING ALOFT DEVELOPING AND WITH MINIMAL LOW AND
MID LEVEL MOISTURE AVAILABILITY TO FUEL THUNDERSTORMS. WITH
1000-500 MB THICKNESSES NEAR 5820 METERS AND 700 MB TEMPERATURES
NEAR 12 CELSIUS...EXPECT HIGH TEMPERATURES TO YIELD 80S AT LOWER
ELEVATIONS...70S OVER THE MOUNTAINS.

TONIGHT...CLEAR AND COOL NIGHT UNDER THE RIDGE ALOFT.

SATURDAY...WITH THE RIDGE AXIS ALOFT MOVING JUST EAST OF OUR
COUNTIES...WARMING SOUTH WINDS AND RISING THICKNESSES AND
TEMPERATURES WILL SPELL A SIGNIFICANT WARMING TREND WITH ABOVE
NORMAL TEMPERATURES. CONTINUED DRY WITH LOW AND MID LEVEL MOISTURE
TOO LIMITED TO FUEL THUNDERSTORMS WITH ENOUGH CONVECTIVE
INHIBITION PRESENT.

SATURDAY NIGHT/SUNDAY/SUNDAY NIGHT...SOUTHWEST FLOW ALOFT
STRENGTHENS. MODELS BRING SOME MONSOONAL MOISTURE TAP INTO OUR
COUNTIES...LOOKING SUFFICIENT ENOUGH TO HELP ERODE THE CONVECTIVE
INHIBITION WITH WARM MID LEVEL TEMPERATURES AND PRODUCE ISOLATED TO
SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS OVER MOST
COUNTIES...FOCUSED ALONG THE SURFACE TROUGH AND DRYLINE PARALLELING
INTERSTATE 25.

.LONG TERM...(MONDAY THROUGH THURSDAY NIGHT)
ISSUED AT 344 AM MDT FRI AUG 28 2015

MODELS REMAIN CONSISTENT WITH THE LONG TERM PATTERN SHOWING
SOUTHWEST FLOW OVER THE FORECAST AREA THROUGH THE WEEK. MONDAY
WILL SEE THE DEEPEST MOISTURE OVERHEAD IN ADVANCE OF A SHORTWAVE
TROUGH MOVING ACROSS THE NORTHERN ROCKIES. A COLD FRONT ASSOCIATED
WITH THIS SYSTEM WILL DROP SOUTH THROUGH THE EASTERN PLAINS IN
THE LATE MORNING AS WELL...WITH SFC WINDS VEERING FROM THE NORTH
TO THE SOUTHEAST IN THE WAKE OF THE FRONT. INCREASED POPS A BIT
ESPECIALLY OVER THE MOUNTAINS AS THE UPPER SHORTWAVE AND LLVL
UPSLOPE FLOW WILL LEND TO BETTER CHANCES FOR SHOWERS/STORMS IN
THESE AREAS...WITH PERHAPS SOME CONVECTION MOVING OUT INTO THE
PLAINS THROUGH THE EVENING DEPENDING ON WHETHER THE ATMOSPHERE CAN
DESTABILIZE SUFFICIENTLY.

POCKETS OF MIDLEVEL MOISTURE WILL CONTINUE TO MOVE OVERHEAD
THROUGH THE END OF THE WEEK ALTHOUGH LACK OF STRONG FORCING WILL
LIMIT WIDESPREAD CONVECTIVE DEVELOPMENT. KEPT JUST A SLIGHT CHANCE
FOR A TSTM OR TWO EACH AFTERNOON IN THE MOUNTAINS THROUGH
THURSDAY. IN ADDITION...A SFC TROUGH PROGGED TO DEVELOP FROM
CHEYENNE TO CHADRON ON WEDNESDAY AFTERNOON COULD PROVIDE ENOUGH
FOCUS FOR AN ISOLATED SHOWER/STORM TO DEVELOP ALONG THIS
CONVERGENCE BOUNDARY. ANOTHER WEAK FRONT WILL THEN SHIFT SOUTHEAST
THRU THE HIGH PLAINS EARLY THURSDAY WITH UPSLOPE FLOW POTENTIALLY
AIDING IN ANOTHER ROUND OF LATE AFTERNOON CONVECTION.

SOUTHWEST SFC WINDS TUE-THURS AHEAD OF THIS FRONT COULD
STRENGTHEN ENOUGH TO DRY OUT LLVL MOISTURE AND INCREASE FIRE
WEATHER CONCERNS MAINLY ACROSS THE HIGH COUNTRY OF SOUTHEAST
WYOMING THRU THIS TIME. WILL HAVE TO KEEP A CLOSE EYE ON THIS
SITUATION AS IT APPROACHES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 546 AM MDT FRI AUG 28 2015

WEATHER CONDITIONS FOR THE NEXT 24HRS SHOULD REMAIN FAIRLY QUIET.
CANNOT RULE OUT A SHOWER OR WEAK T-STORM DEVELOPING OVER THE
LARAMIE RANGE AND TRACKING SOUTHEAST AFTER 18Z...PERHAPS NEAR
KCYS. OTHERWISE...MOSTLY CLEAR SKIES WILL PREVAIL. NORTH WINDS
GUSTING TO 20 KTS ARE EXPECTED FROM KAIA TO KSNY FROM ROUGHLY 17Z
THROUGH THE EARLY EVENING.

&&

.FIRE WEATHER...
ISSUED AT 344 AM MDT FRI AUG 28 2015

MINIMAL CONCERNS TODAY BASED ON EXPECTED HUMIDITIES AND WINDS.
HOWEVER...WILL NEED TO WATCH SATURDAY AFTERNOON CAREFULLY ACROSS
CONVERSE COUNTY AS HUMIDITIES AND WINDS WILL APPROACH CRITICAL
CONDITIONS...THOUGH THIS LOOKS LIKE A MARGINAL EVENT BASED ON
CURRENT MODEL RUNS. LESSENING CONCERNS SUNDAY AND MONDAY...THEN WE
WILL NEED TO MONITOR TUESDAY THROUGH FRIDAY CAREFULLY AS
HUMIDITIES LESSEN AND GUSTY WINDS DEVELOP AT TIMES IN THE
AFTERNOONS AND EVENINGS.

&&

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

$$

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



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