Area Forecast Discussion
Issued by NWS Cheyenne, WY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KCYS 060002
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
602 PM MDT SUN JUL 5 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 436 PM MDT SUN JUL 5 2015

CONVECTION HAS REALLY INCREASED THROUGH THE EARLY AFTN OVER
ALBANY/LARAMIE COUNTIES AND PORTIONS OF THE SOUTHERN PANHANDLE.
THIS DEVELOPMENT IS OCCURRING IN ADVANCE OF A WEAK SHORTWAVE LOCATED
OVER WESTERN COLORADO/WYOMING.  THE STORMS OVER LARAMIE COUNTY HAVE
BEEN HEAVY RAIN PRODUCERS WITH A FEW LOCATIONS SHOWING RADAR DERIVED
AMOUNTS OF ONE TO THREE INCHES.  PLENTIFUL MONSOONAL MOISTURE IS
MOVING NORTHEASTWARD INTO THE CWA WITH PW VALUES ABOVE 1.25 INCHES
ACROSS THE PLAINS.  IT APPEARS THAT THE RAIN IS BECOMING MORE
STRATIFORM THOUGH OVER SOUTHEAST WYOMING BEHIND THE COLD FRONT WHICH
SHOULD REDUCE THE HEAVY RAIN/FLASH FLOOD THREAT THROUGH THE
REMAINDER OF THE EVENING.  THE POTENTIAL EXISTS FOR STRONG TO SVR
STORMS TO DEVELOP OVER MAINLY THE FAR PANHANDLE THROUGH THIS
EVENING. SPC MESOANALYSIS SHOWS GOOD INSTABILITY (MLCAPES OF 2000-
2500 J/KG) IN NORTHERN SIOUX AND DAWES COUNTIES WITH BULK SHEAR OF
30 KTS.  THERE IS LESS INSTABILITY TO THE SOUTH ALONG INTERSTATE 80.
A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 11 PM FOR ZONES ALONG
THE EASTERN CWA BORDER IN THE PANHANDLE.  SHORTWAVE TROUGH WILL PASS
EASTWARD INTO WESTERN NEBRASKA BY LATER TONIGHT WITH THE FRONT
PASSING OVER THE ENTIRE CWA.  WILL KEEP 50-70 PERCENT POPS GOING
THROUGH MUCH OF THE NIGHT...BUT AGAIN THE RAIN SHOULD BE MORE
STRATIFORM IN NATURE.

MUCH COOLER ON MONDAY IN THE POST FRONTAL AIRMASS.  SCATTERED
SHOWERS COULD CONTINUE INTO MID MORNING ACROSS SOUTHEAST WY BEFORE
TAPERING OFF.  INSTABILITY WILL BE MUCH LESS THAN PREVIOUS DAYS WITH
THE BEST CHANCE OF THUNDER CONFINED TO AREAS ALONG AND WEST OF THE
LARAMIE RANGE.  CONVECTION BECOMES MORE WIDESPREAD ONCE AGAIN ON
TUES ESPECIALLY OVER SOUTHEAST WYOMING.  CAPE DOES INCREASE TO
AROUND 1000 J/KG ALONG THE LARAMIE RANGE BY THE AFTN BUT DROPS OFF
QUICKLY ACROSS THE PLAINS. GET SOME WARMING ON TUES...HOWEVER TEMPS
WILL STILL BE ABOUT 10 DEGREES BELOW NORMAL.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 436 PM MDT SUN JUL 5 2015

UNSETTLED AND WARMER CONDITIONS WILL CONTINUE THROUGH THE END OF
THE WEEK AS MOIST SOUTHWEST FLOW REMAINS OVER THE FORECAST AREA.
TEMPERATURES WILL WARM FROM THE 60S AND 70S ON WEDNESDAY BACK INTO
THE UPPER 70S TO LOW 90S FROM WEST TO EAST BY FRIDAY. A FEW PIECES
OF ENERGY WILL MOVE OVERHEAD ON WEDNESDAY...AND WITH PLENTIFUL
MOISTURE IN PLACE THROUGH THE ATMOSPHERIC COLUMN COMBINING WILL
DECENT LLVL UPSLOPE FLOW...SHOULD SEE A GOOD CHANCE FOR SHOWERS
AND THUNDERSTORMS THROUGH THE DAY. DEEP LAYER SHEAR CONTINUES TO
LOOK FAVORABLE FOR A FEW STRONGER STORMS ON WEDNESDAY
AFTERNOON/EVENING SO WILL KEEP MENTION FOR THAT POSSIBILITY IN THE
FORECAST. THURSDAY WILL BE QUITE SIMILAR...HOWEVER INCREASING
TEMPERATURES ALOFT WILL DIMINISH COVERAGE FOR SHOWERS AND
THUNDERSTORMS A BIT WITH THE BEST CHANCE EXPECTED OVER THE
MOUNTAINS. CHANCES FOR STRONG STORMS WILL BE LESS AS WELL. MODELS
ARE CONSISTENT WITH SHOWING THE UPPER LOW OVER CALIFORNIA
BECOMING AN OPEN WAVE AS IT MOVES NORTHEAST ACROSS THE GREAT
BASIN. GFS CONTINUES TO BE THE WETTER SOLUTION VS THE ECMWF ON
FRIDAY...BUT BOTH MODELS SHOW AFTERNOON CONVECTION DEVELOPING IN
THE MOUNTAINS. THE WETTER GFS CARRIES THE CONVECTION EAST IN THE
EVENING WHILE THE DRIER ECMWF KEEPS THE EASTERN ZONES DRY. WILL
KEEP SLIGHT CHANCE POPS IN FOR FRIDAY EVENING UNTIL MODELS BECOME
MORE CONSISTENT. FOR SATURDAY...BOTH MODELS BUILD A STRONG UPPER
LEVEL HIGH PRESSURE CENTER INTO THE SOUTHERN PLAINS...WITH THE
ECMWF BUILDING THAT RIDGE UP INTO THE ROCKIES AS WELL. THE GFS IS
STARTING TO TREND THAT WAY...BUT STILL SWEEPS A BIT MORE MIDLEVEL
ENERGY ACROSS OUR AREA IN THE EVENING. MAINTAINED A SLIGHT CHANCE
FOR T-STORMS OVER THE MOUNTAINS TO ACCOUNT FOR MODEL
DIFFERENCES...BUT LEFT REMAINING AREAS DRY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 602 PM MDT SUN JUL 5 2015

THE COLD FRONT HAS PASSED THROUGH THE EASTERN PLAINS AND IS
WORKING ITS WAY SOUTH THROUGH THE HIGH COUNTRY AT 00Z...WITH
GUSTY NORTH WINDS OCCURRING IN ITS WAKE. WIDESPREAD SHOWERS AND
SCATTERED THUNDERSTORMS HAVE OVERSPREAD THE AREA THIS AFTERNOON
WITH MVFR TO BRIEF IFR CONDITIONS IN THE HEAVIER ACTIVITY. STILL
THINK THAT RAIN AND A FEW EMBEDDED THUNDERSTORMS WILL OCCUR
OVERNIGHT WITH STRATUS DEVELOPING AS WELL OVER MUCH OF THE AREA
MAINLY AFTER 04Z. IFR CONDITIONS SHOULD BE CONFINED ALONG THE
CHEYENNE RIDGE WHILE MVFR CONDITIONS WILL BE MORE WIDESPREAD
ELSEWHERE. CONDITIONS WILL SLOWLY IMPROVE MID MONDAY MORNING BUT
NOT CONFIDENT CIGS WILL BECOME VFR...EXCEPT FOR KAIA AND KCDR.
LIKELY WILL SEE SCT-BKN MVFR CIGS PERSIST THROUGH MUCH OF THE
DAY...WITH AFTERNOON SHOWERS AND T-STORMS RETURNING MAINLY OVER
THE MOUNTAINS.

&&

.FIRE WEATHER...
ISSUED AT 436 PM MDT SUN JUL 5 2015

NO FIRE WEATHER CONCERNS THROUGH THE MIDDLE OF NEXT WEEK.
WIDESPREAD WETTING RAINS WILL OCCUR THROUGH TONIGHT OVER MUCH OF THE
REGION.  A COLD FRONT WILL BRING MUCH COOLER TEMPERATURES ON MONDAY.
 MINIMUM AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 40
PERCENT THROUGH WEDNESDAY.  THERE WILL BE A CHANCE OF AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS EACH DAY THROUGH THE MIDDLE OF THE
NEXT WEEK.

&&

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

$$

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.