Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 201751
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1151 AM MDT SUN JUL 20 2014

.UPDATE...
ISSUED AT 1010 AM MDT SUN JUL 20 2014

NO SIGNIFICANT CHANGES NEEDED FOR THE AM UPDATE. ANOTHER VERY HOT
DAY IN STORE FOR THE CWA...ESPECIALLY FOR THE LOWER ELEVATIONS OF
THE PLATTE RIVER VALLEY IN THE WESTERN PANHANDLE. UPPER LOW MOVING
NORTHWARD THROUGH THE GREAT BASIN WILL PUSH SOME MIDLVL MOISTURE
IN OUR DIRECTION OVER THE NEXT FEW HOURS...SO PCPN SHOULD INCREASE
IN COVERAGE ALONG AND WEST OF THE LARAMIE RANGE BY AFTN. VISIBLE
SATELLITE SHOWS CLOUDS AND WEAK SHOWERS NOW MOVING INTO SOUTHWEST
CARBON COUNTY...SO WILL INTRODUCE LATE AM POPS. OTHERWISE THINGS
ARE LOOKING GOOD. MIGHT SEE SOME LATE AFTN OR EARLY EVE SHOWERS
AROUND CYS LATE THIS AFTN OR EARLY EVE WITH WEAK WAVES EMANATING
FROM THE LOW OUT WEST. RED FLAG WARNING FOR FWZ 301-302-306 IS ON
TRACK. SFC OBS SHOW RH VALUES ALREADY AROUND 15 PERCENT AND WINDS
SHOULD PICK UP SHORTLY ONCE MIXING ENSUES. BUMPED UP START TIME TO
1100 AM.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 145 AM MDT SUN JUL 20 2014

TODAY...ANOTHER HOT AND MOSTLY DRY DAY WITH RIDGING ALOFT OVER OUR
COUNTIES. DESPITE WARM MID LEVEL TEMPERATURES...LOOKS LIKE ENOUGH
MID LEVEL MOISTURE AND DIURNAL HEATING FOR ISOLATED LATE DAY HIGH
BASED THUNDERSTORMS ALONG AND WEST OF INTERSTATE 25. 24 HOUR CHANGE
CHART SHOWS TEMPERATURES MOSTLY RUNNING SOME 2 TO 8 DEGREES ABOVE 24
HOURS AGO WITH DRIER LOW LEVELS VIA DEWPOINTS.

TONIGHT...AFTER ISOLATED EARLY EVENING THUNDERSTORMS
DIMINISH...ANOTHER MOSTLY CLEAR AND MILD OVERNIGHT WITH SOUTHWEST
FLOW ALOFT.

MONDAY...RIDGING AND TEMPERATURES ALOFT PROGGED TO BE SLIGHTLY
HIGHER AND WITH MORE LIMITED LOW AND MID LEVEL MOISTURE...LESS
THUNDERSTORM COVERAGE ANTICIPATED.

MONDAY NIGHT...WEAK SHORTWAVE TROUGH ALOFT MOVING ACROSS THE DAKOTAS
WILL SEND A WEAK COLD FRONT ACROSS OUR COUNTIES.

TUESDAY...LOW LEVEL WINDS WILL BE UPSLOPE FROM THE SOUTHEAST IN THE
WAKE OF THE WEAK SURFACE COLD FRONT...THOUGH WITH THE RIDGE
STRENGTHENING ALOFT EVEN MORE AND WARM MID LEVEL TEMPERATURES...NO
THUNDERSTORMS EXPECTED.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 145 AM MDT SUN JUL 20 2014

PRETTY STRONG RIDGE OF HIGH PRESSURE OVER WYOMING TUESDAY NIGHT.
BOTH THE GFS AND NEW ECMWF RUN SHOWS 597DM HEIGHTS OVER THE STATE
WITH A 600DM 500MB HIGH OVER COLORADO. 700MB TEMPERATURES PUSHING
18C ACROSS CARBON COUNTY...SO TEMPERATURES ARE GOING TO BE VERY
WARM. LOOKING AT OVERNIGHT LOWS IN THE LOW TO MID 60S OUT IN THE
PANHANDLE/MID TO UPPER 50S ACROSS SOUTHEAST WYOMING.

GET SOME RELIEF FROM THE HEAT WEDNESDAY AS SOUTHEAST FLOW RETURNS
ACROSS THE PANHANDLE. UPPER LEVEL HEIGHTS FALL TO 594DM AND 700MB
TEMPERATURES FALL BACK SOME TO +14 TO +16C. BOTH THE GFS AND ECMWF
DO BEGIN TO POOL SOME LOW LEVEL MOISTURE INTO THE PANHANDLE AND
EAST OF THE LARAMIE RANGE...SO KEPT SOME LOW END CHANCE TO SLIGHT
CHANCE POPS GOING WEDNESDAY AFTERNOON.

ANOTHER LOW PRESSURE SYSTEM TRACKS ACROSS MONTANA FRIDAY AND
STRONG WINDS WILL CONTINUE AS GFS 700MB WINDS OF 30-35KTS. SOME
RELIEF THOUGH ON TEMPERATURES THOUGH AS GFS 700MB TEMPERATURES
FALL TO +10 TO +12C FRIDAY EVENING INTO SATURDAY.

SURFACE LOW MOVES EAST THURSDAY AND WEST WINDS TURN MORE
WESTERLY/INCREASE THURSDAY AFTERNOON. WILL PROBABLY BE DEALING
WITH FIRE WEATHER ISSUES WITH THESE GUSTY WINDS AS AFTERNOON
HUMIDITIES FALL TO THE UPPER SINGLE DIGITS WEST OF THE LARAMIE
RANGE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING)
ISSUED AT 1151 AM MDT SUN JUL 20 2014

ANOTHER QUIET AVIATION PERIOD SHAPING UP AS VFR CONDITIONS WILL
CONTINUE AT TAF SITES. THERE IS A SOME MONSOONAL MOISTURE THAT
WILL ROTATE NORTHEAST INTO SOUTHEAST WYOMING THIS AFTERNOON AND
MAY PRODUCE A FEW WEAK SHOWERS. FOR NOW...IT LOOKS LIKE KRWL WOULD
HAVE THE BEST OPPORTUNITY TO SEE THIS ACTIVITY...SO HAVE KEPT THE
VCSH GOING THERE. OTHERWISE...JUST SEE SOME INCREASING MID-LEVEL
CLOUDINESS THRU THE AFTERNOON. WINDS AND ANY CONVECTION THAT IS
ABLE TO DEVELOP WILL DECREASE BY AROUND SUNSET.

&&

.FIRE WEATHER...
ISSUED AT 145 AM MDT SUN JUL 20 2014

RED FLAG CONDITIONS LOOK LIKELY THIS AFTERNOON AND
EARLY EVENING FOR FIRE WEATHER ZONES 301...302 AND 306 BASED ON
CURRENT TRENDS...AND PROGGED HUMIDITIES AND WINDS THIS AFTERNOON.
MAY SEE RED FLAG CONDITIONS AGAIN ON MONDAY THROUGH HUMIDITIES
SLIGHTLY HIGHER.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ301-302-306.

NE...NONE.
&&

$$

UPDATE...HAMMER
SHORT TERM...RUBIN
LONG TERM...CLAYCOMB
AVIATION...HAHN
FIRE WEATHER...RUBIN





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