Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 070456
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1056 PM MDT MON JUL 6 2015

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 245 PM MDT MON JUL 6 2015

EASTERLY FLOW IN THE LOW LEVELS IS MAINTAINING THE STRATUS DECK
ALONG AND EAST OF THE LARAMIE RANGE THIS AFTERNOON...WHILE CLOUDS
HAVE LIFTED SIGNIFICANTLY FURTHER WEST INTO CARBON COUNTY WITH
INCREASING SUNSHINE OVER THIS AREA. A FEW THUNDERSTORMS HAVE
DEVELOPED JUST SOUTH OF THE BORDER IN THE COLORADO MOUNTAINS WHERE
SBCAPES HAVE INCREASED TO BETWEEN 500-1000 J/KG. EXPECT T-STORMS TO
DEVELOP OVER THE SOUTHEAST WYOMING MOUNTAINS AS WELL OVER THE NEXT
COUPLE OF HOURS AS THE ATMOSPHERE FURTHER DESTABILIZES HERE. ACROSS
THE EAST...MUCH COOLER TEMPS UNDER THE STRATUS DECK WILL KEEP T-
STORM CHANCES MINIMAL. THERE REMAINS A LOW CHANCE FOR A STRAY STORM
OR TWO JUST TO THE EAST OF THE LARAMIE RANGE THIS AFTERNOON/EVENING
DEPENDING ON WHETHER ANY STORMS FIRE OVER THE LARAMIE RANGE.
OTHERWISE...SHOULD REMAIN MOSTLY DRY ACROSS THE EASTERN PLAINS UNDER
STABLE CONDITIONS AND DECREASING LIFT FROM ABOVE. NORTHERLY WINDS
BEHIND YESTERDAYS COLD FRONT OPENED THE DOOR FOR WILDFIRE SMOKE TO
FILTER INTO OUR FORECAST AREA TODAY. MANY LOCATIONS ACROSS THE
PLAINS ARE SEEING VISIBILITIES OF 2 TO 5SM...SO NOT A SIGNIFICANT
IMPACT BUT ENOUGH TO BE A NUISANCE. WINDS WILL STEADILY SHIFT TO THE
SOUTHEAST THIS EVENING AND OVERNIGHT WHICH WILL HOPEFULLY PUSH THE
SMOKE BACK NORTH FOR TONIGHT. FOR TONIGHT...MOUNTAIN SHOWERS AND
STORMS WILL STEADILY DIMINISH THROUGH THE EVENING WITH SOUTHEASTERLY
UPSLOPE FLOW INCREASING ALONG THE EASTERN PLAINS. SHOULD SEE PATCHY
FOG AND DRIZZLE ONCE AGAIN ALONG THE LARAMIE RANGE OVERNIGHT ALONG
WITH SOME FOG POSSIBLY SPILLING INTO THE LARAMIE VALLEY WESTWARD
ALONG THE I-80 CORRIDOR AS LLVL FLOW STRENGTHENS.

A STRONGER SHORTWAVE TROUGH WILL MOVE OVERHEAD ON TUESDAY OVER
PERSISTENT SOUTHEASTERLY UPSLOPE FLOW. A BROADER COVERAGE OF SHOWERS
AND THUNDERSTORMS IS EXPECTED ALONG AND WEST OF THE LARAMIE RANGE AS
THE WAVE MOVES OVERHEAD AND TEMPS WARM. FURTHER EAST...EXPECT STORMS
TO DEVELOP ALONG THE LARAMIE RANGE AND MOVE OFF TO THE
EAST...HOWEVER COVERAGE AND STRENGTH OF THIS ACTIVITY WILL DEPEND ON
WHEN THE STRATUS DECK BREAKS UP. MODELS ARE CONSISTENT WITH KEEPING
MOST OF THE ACTIVITY OVER SOUTHEAST WYOMING LIKELY TIED TO
OROGRAPHICS. HOWEVER...SOME ACTIVITY LOOKS TO MOVE INTO THE NEBRASKA
PANHANDLE...BUT COVERAGE IN GENERAL LOOKS MORE ISOLATED HERE.
TRENDED POPS TOWARDS THIS THINKING. COULD SEE SOME HEAVY RAIN AND
SMALL HAIL ONCE AGAIN IN A FEW STRONGER STORMS THAT ARE POSSIBLE
OVER THE HIGH COUNTRY.

WEDNESDAY LOOKS VERY SIMILAR TO TUESDAY WITH THE ADDITION OF A COLD
FRONT WHICH LOOKS TO DROP SOUTH ACROSS THE AREA IN THE MORNING. SO
PERHAPS WILL HAVE A BETTER OVERALL CHANCE FOR SHOWERS AND T-STORMS
THROUGH THE DAY. STRONGER STORMS MAY OCCUR FURTHER EAST ACROSS THE
PLAINS AS WELL WITH BETTER INSTABILITY AND SFC FORCING OVER THIS
AREA.

TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH MIDWEEK.

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 245 PM MDT MON JUL 6 2015

WITH MOIST SOUTHWESTERLY MIDLVL FLOW IN PLACE ON THURS...WILL
LIKELY SEE A SCATTERED COVERGE OF STORMS BEFORE THINGS DRY
SUBSTANTIALLY INTO THE WEEKEND. PW VALUES ARE AROUND 1 INCH ON
THURS AFTN TO THE EAST OF THE LARAMIE RANGE. THE GFS DOES SHOW
GOOD INSTABILITY (CAPE VALUES OF 1250-1500) TO THE EAST OF THE
LARAMIE RANGE...SO WOULD BE CONCERNED WITH A STRONG STORM OR TWO.
LEE TROUGH DEVELOPS BY FRI AS A WEAKENING SHORTWAVE MOVES OVER
WYOMING. THE BEST MOISTURE WILL BE PUSHED EAST INTO NEBRASKA WITH
PW VALUES DROPPING BELOW 0.5 INCHES OVER SOUTHEAST WY. HAVE LOWER
POPS ON FRI WITH THE DRIER AIRMASS MOVING IN. BOTH THE GFS AND
ECMWF ARE STILL SHOWING VERY LITTLE STORM ACTIVITY OVER THE
WEEKEND AS THE SUBTROPICAL RIDGE BUILDS OVER COLORADO WITH
SUBSIDENCE/WARMING ALOFT. TEMPS WILL BE A FEW DEGREES BELOW NORMAL
ON THURS...BEFORE WARMING 10-15 DEGREES INTO THE WEEKEND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1055 PM MDT MON JUL 6 2015

CIGS WILL LIFT SLOWLY TONIGHT FOR MOST OF WESTERN
NEBRASKA...ALTHOUGH LOW VIS DUE TO HAZE WILL HAVE TO BE MONITORED.
VIS HAS TRENDED HIGHER THIS EVENING...SO EXPECT MOST OF THE HAZE
TO DISSIPATE BY MIDNIGHT. SOME PATCHY FOG IS THEN POSSIBLE BY
EARLY TUESDAY MORNING...MAINLY AROUND KCYS WITH IFR CONDITIONS
EXPECTED TO REDEVELOP.

&&

.FIRE WEATHER...
ISSUED AT 245 PM MDT MON JUL 6 2015

TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH MUCH OF THIS WEEK
WHILE THE WET PATTERN CONTINUES. THEREFORE...NO FIRE WEATHER
CONCERNS ARE ANTICIPATED IN THE NEAR TERM. CONDITIONS WILL BEGIN TO
DRY AND WARM THIS WEEKEND.

&&

.HYDROLOGY...
ISSUED AT 245 PM MDT MON JUL 6 2015

POCKETS OF HEAVY RAIN PRODUCED SOME FLASH FLOODING INTO MORRILL
COUNTY NEBRASKA SUNDAY EVENING. WHILE THE WATERS HAVE RECEDED...
SOME STANDING WATER MAY REMAIN OVER THE NEXT DAY OR SO.
FORTUNATELY...DRIER CONDITIONS WILL REMAIN IN PLACE FOR THE NEXT 24
HOURS OR SO. IN ADDITION...CROW CREEK IN CHEYENNE HAS RISEN ABOUT A
FOOT TODAY FROM HEAVY RAINFALL THAT OCCURRED NORTHWEST OF CHEYENNE
YESTERDAY AFTERNOON. EXPECT TO SEE WATER LEVELS CREST THIS
EVENING...WHICH WILL BE WELL BELOW ACTION STAGE. CHANCES FOR SHOWERS
AND THUNDERSTORMS WILL INCREASE TUESDAY NIGHT INTO WEDNESDAY NIGHT
WITH LOCALLY HEAVY RAIN NOT OUT OF THE QUESTION. WHILE THE WET
WEATHER PATTERN IS LIKELY THROUGH FRIDAY...THE WEEKEND IS STARTING
TO LOOK PROMISING WITH DRIER AIR MOVING INTO THE REGION.

&&

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

$$

SHORT TERM...RJM
LONG TERM...ZF
AVIATION...TJT
FIRE WEATHER...RJM


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