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 110942
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
342 AM MDT FRI JUL 11 2014

.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 330 AM MDT FRI JUL 11 2014

WATER VAPOR IMAGERY SHOWS THE SUBTROPICAL MONSOONAL MOISTURE PLUME
OVERHEAD WITH THE MID LEVEL RIDGE CENTER LOCATED IN NORTHEASTERN NEW
MEXICO.  LLVL MOISTURE IS ALSO HIGH IN ADDITION TO THE ABUNDANT MID LEVEL
MOISTURE...AS SFC DEW POINTS ARE IN THE MID 50S TO LOWER 60S OVER THE
ENTIRE CWA.  THE POTENTIAL FOR WIDESPREAD SHOWERS AND TSTMS THIS
AFTN...SOME PRODUCING HEAVY RAIN...CONTINUES TO LOOK ON TRACK.  PW
VALUES WILL BE VERY HIGH AT 1.25-1.50 INCHES FOR AREAS ALONG AND
EAST OF THE LARAMIE RANGE.  LLVL WINDS WILL BECOME EAST IN THE AFTN
AND THIS INCREASING UPSLOPE WILL COMBINE WITH A WEAK SHORTWAVE TO
EFFECTIVELY TRIGGER THE CONVECTION.  MAIN CONCERN WITH THE STORMS
WILL BE HEAVY RAIN AND INCLUDED THIS IN THE GRIDS.  STEERING FLOW
WILL BE SOUTHWESTERLY AT 15-20 KT...WHICH IS LIKELY FAST ENOUGH TO
LIMIT THE FLASH FLOOD THREAT FROM ANY PARTICULAR CELL...HOWEVER WE
WILL HAVE TO WATCH FOR TRAINING.  DID NOT ISSUE A FLASH FLOOD WATCH
DUE TO THE MODERATE STORM SPEEDS AND THE FACT THAT MUCH OF THE CWA
HAS NOT SEEN A WHOLE LOT OF RAIN OVER THE PAST FEW WEEKS.  THE
HIGHEST RAINFALL AMOUNTS FROM YESTERDAYS ACTIVITY WAS OVER PORTIONS
OF MORRILL AND BOX BUTTE COUNTIES (AROUND 1-2.5 INCHES) SO THIS
PARTICULAR AREA WILL HAVE TO BE MONITORED CLOSELY.

WHILE THE MAIN IMPACT FROM THE STORMS TODAY WILL BE THE HEAVY RAIN...
THERE IS ALSO A SLIGHT RISK OF SEVERE TSTMS ACROSS MUCH OF THE
PLAINS. THE HIGH DEW POINTS WILL CAUSE CAPE VALUES TO BE IN THE
1000-1500 J/KG RANGE...HIGHEST OVER THE NEBRASKA PANHANDLE. THERE
IS ENOUGH DEEP LAYER SHEAR (25-35 KT) DUE TO THE LLVL EASTERLY
WINDS TO PROMOTE AN ISOLATED DISCRETE SUPERCELL AT LEAST INITIALLY...
ALTHOUGH STORMS COULD BECOME MORE MULTI-CELLULAR BY THE TIME THEY
REACH THE PANHANDLE. WHILE A FEW STORMS PRODUCING NICKEL TO QUARTER
SIZED HAIL WILL DEFINITELY BE POSSIBLE...WATER LOADING OF UPDRAFTS
AND MARGINAL BULK SHEAR WILL BE LIMITING FACTORS FOR LARGER HAIL.

WEAK COLD FRONT WILL PUSH ACROSS THE CWA ON SAT MORNING SO TEMPS WILL
BE ABOUT 5 DEGREES COOLER ON SAT. THE BEST MID LEVEL MOISTURE AND
AXIS OF HIGHEST PW VALUES WILL BEGIN TO BE SHUNTED SOUTH INTO COLORADO
DURING THE AFTN...HOWEVER THEY ARE STILL ELEVATED OVER THE CWA (AROUND
1 INCH). THE SLIGHT DRYING OCCURS AS THE FLOW ALOFT BECOMES MORE
NORTHWESTERLY. SO HAVE LESS STORM COVERAGE ON SAT WITH THE BEST CHANCES
ALONG THE COLORADO BORDER. PRETTY MUCH A REPEAT FOR SUN AS THE SYNOPTIC
CONDITIONS DO NOT REALLY CHANGE.

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 330 AM MDT FRI JUL 11 2014

00Z MEDIUM RANGE MODEL CONSENSUS MAINTAINS A NORTHWEST FLOW ALOFT NEXT
WEEK AS A ANOMALOUSLY DEEP UPPER TROUGH OCCUPIES THE MIDWEST AND STOUT
UPPER RIDGE REMAINS NEARLY STATIONARY OVER THE GREAT BASIN. MONDAY WILL
TREND DRIER WITH THE RESURGENCE OF A COOLER AIR MASS FROM THE CANADIAN
PRAIRIES INTO THE NORTH CENTRAL CONUS. WEAK UPSLOPE BEHIND A COLD FRONT
DRAPED NEAR THE FRONT RANGE MOUNTAINS WILL RESULT IN ISOLATED AFTERNOON
AND EARLY EVENING CONVECTION SOUTH OF A DOUGLAS-ALLIANCE LINE. MONSOONAL
MOISTURE AND WEAK SHORTWAVE RIDING SOUTHEAST ALONG THE FRONT RANGE WILL
BRING MORE SCATTERED AFTERNOON AND EVENING CONVECTION WEST OF A DOUGLAS-
SIDNEY LINE TUESDAY. THE FRONT ALONG THE FRONT RANGE DRIFTS EAST ONTO
THE PLAINS WEDNESDAY ALONG WITH ISOLATED TO SCATTERED AFTERNOON AND
EVENING CONVECTION. UPPER RIDGE TO THE WEST BEGINS TO MAKE ITS PRESENCE
FELT THURSDAY WITH SOME WARMING ALOFT RESULTING IN MORE ISOLATED DIURNAL
CONVECTION. TEMPERATURES WILL TREND BELOW SEASONAL NORMALS FOR THE FIRST
HALF OF THE WEEK THEN WARM TO NEAR NORMAL THURSDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 330 AM MDT FRI JUL 11 2014

A WEAK DISTURBANCE PRODUCING SCATTERED SHOWERS AND ISOLATED TSTORMS
ACROSS THE PLAINS WILL EXIT THE REGION EARLY THIS MORNING. MONSOONAL
MOISTURE AND INSTABILITY WILL SET THE STAGE FOR WIDESPREAD CONVECTION
THIS AFTERNOON AND EVENING WITH ALL TERMINALS AFFECTED. MVFR TO IFR
VISIBILITIES IN HEAVY RAIN WILL BE THE MAIN IMPACT FROM THE TSTORMS.
THE STRONGEST TSTORMS MAY ALSO PRODUCE HAIL AND WIND GUSTS TO 50 KT.

&&

.FIRE WEATHER...
ISSUED AT 330 AM MDT FRI JUL 11 2014

NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. ABUNDANT MONSOONAL
MOISTURE WILL PRODUCE WIDESPREAD SHOWERS AND THUNDERSTORMS THIS
AFTERNOON AND EVENING. SOME OF THE STORMS COULD PRODUCE MODERATE TO
HEAVY RAINFALL. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
EACH AFTERNOON ON SATURDAY AND SUNDAY. DUE TO THE HIGH MOISTURE
LEVELS...MINIMUM RELATIVE HUMIDITY VALUES WILL GENERALLY BE ABOVE 35
PERCENT OVER THE ENTIRE AREA.

&&

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

$$

SHORT TERM...FINCH
LONG TERM...JAMSKI
AVIATION...JAMSKI
FIRE WEATHER...FINCH




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