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 242112
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
312 PM MDT FRI APR 24 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 155 PM MDT FRI APR 24 2015

THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE PRECIPITATION
TYPE THIS WEEKEND AND WHERE THE BEST CHANCE OF SNOW WILL BE.

TONIGHT:
LATEST RADAR LOOP WAS SHOWING THE BULK OF THE CONVECTION ALONG AND
SOUTH OF INTERSTATE 80 THIS AFTERNOON. HOWEVER...THERE IS A
FRONTAL BOUNDARY MOVING SOUTH THROUGH FALL RIVER COUNTY IN SOUTH
DAKOTA WITH A CLUSTER OF THUNDERSTORMS ASSOCIATED WITH IT. THIS
CLUSTER OF THUNDERSTORMS SHOULD BEGIN TO MOVE INTO SIOUX AND DAWES
COUNTY DURING THE NEXT HOUR OR TWO. THIS CLUSTER OF THUNDERSTORMS
SHOULD BEGIN TO DISSIPATE AFTER SUNSET AS IT PUSHES SOUTHEAST. THE
REST OF THE EVENING SHOULD BE FAIRLY QUIET WITH LITTLE IF ANY
CONVECTION EXPECTED. THE CHANCE OF SHOWERS DOES INCREASE ACROSS
CARBON COUNTY LATE TONIGHT AS 300-305K THETA SURFACES BEGIN TO
RISE AS THE SHORTWAVE STARTS DIVING SOUTH THROUGH THE
INTERMOUNTAIN WEST.

SATURDAY:
MOISTURE TRANSPORT BEGINS TO INCREASE FROM WEST TO EAST
ALONG WITH RISING THETA SURFACES AS THE SHORTWAVE CONTINUES TO
DIVE SOUTH. THIS WILL HELP ENHANCE THE LEE SIDE TROF AND BRING IN
THE DEEPER LOW LEVEL MOISTURE ALONG AND EAST OF THE LARAMIE RANGE
DURING THE COURSE OF THE DAY. THIS WILL SET THE STAGE FOR NUMEROUS
SHOWERS AND THUNDERSTORMS. NOT EXPECTING ANYTHING SEVERE AT THIS
POINT. THESE SHOWERS AND THUNDERSTORMS WILL IMPACT AREAS ALONG
AND WEST OF THE LARAMIE RANGE DURING THE MORNING WITH THIS
ACTIVITY LINGERING IN THIS REGION DURING THE AFTERNOON.
MEANWHILE...AREAS EAST OF THE LARAMIE RANGE WILL SEE THE BULK OF
THE SHOWERS AND THUNDERSTORMS DEVELOP DURING THE AFTERNOON WITH
PARTLY TO MOSTLY CLOUDY SKIES DURING THE MORNING.

SATURDAY NIGHT:
THE UPPER LEVEL LOW IS EXPECTED TO MOVE INTO UTAH AND WESTERN COLORADO
BY SUNDAY MORNING. AS A RESULT...DEEPER MOISTURE WILL CONTINUE TO
FEED INTO THE AREA. NOT COMPLETELY SURE WHERE THE BAND OF
PRECIPITATION WILL SETUP. THE MODELS ARE POINTING THE
PANHANDLE...BUT WE ARE ALSO CONCERNED ABOUT SOUTHEAST WYOMING IN
PROXIMITY OF THE LEE SIDE TROF. IF THIS UPSLOPE PERSIST ALONG WITH
GOOD UPPER LEVEL DIFFLUENCE...THIS AREA MAY GET TARGETED AS WELL.
WE WILL HAVE TO KEEP AN EYE ON THIS REGION ESPECIALLY IF
TEMPERATURES DROP TO THE MID 30S ON THE SUMMIT. THIS COULD CAUSE A
VISIBILITY REDUCTION FROM THE SNOW/FOG.

SUNDAY-SUNDAY NIGHT:
UPPER LEVEL DIFFLUENCE COMBINED WITH UPSLOPE FLOW WILL RESULT IN A
WET CONDITIONS DURING THIS TIMEFRAME. HOWEVER...THIS WILL BRING
SOME DECENT PRECIPITATION. AT THIS POINT...WE ARE LOOKING AT
AROUND 1 INCH OF RAINFALL IN AREAS MAINLY ALONG AND EAST OF THE
LARAMIE RANGE. MEANWHILE...HIGHER ELEVATIONS ABOVE 8000FT
INCLUDING THE SUMMIT MAY SEE SOME ACCUMULATING SNOWFALL. AT THIS
POINT...WE ARE EXPECTING ABOUT A COUPLE OF INCHES OF SNOW ON THE
I-80 SUMMIT SUNDAY NIGHT WITH REDUCED VISIBILITY AND POTENTIAL
SLICK ROADS. THE SNOWY AND SIERRA MADRE RANGE MAY ALSO RECEIVE 5
TO 10 INCHES.



.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 155 PM MDT FRI APR 24 2015

MONDAY THROUGH FRIDAY...

THE STRONG UPPER LOW WILL SLOWLY MEANDER EASTWARD INTO THE SOUTHERN
PLAINS ON MONDAY WITH FLOW THROUGH THE COLUMN STEADILY SHIFTING FROM
THE SOUTHEAST IN THE MORNING...TO THE NORTH-NORTHEAST BY THE EVENING
AS A SHORTWAVE TROUGH MOVES ACROSS THE NORTHERN ROCKIES AND PLAINS.
OUR CWA WILL BASICALLY BE CENTERED IN BETWEEN THESE TWO SYSTEMS SO
WILL BE IN SPLIT FLOW...HOWEVER SOME JET ENERGY WILL MOVE OVERHEAD
AS THE STRONGEST CORE OF THE MERIDIONAL JET SHIFTS TO THE NORTH AND
THE LEFT EXIT REGION POSITIONS OVERHEAD. TIMING THE COLD FRONTAL
PASSAGE ASSOCIATED WITH THE NORTHERN SYSTEM IS A BIT TOUGH AT THIS
TIME WITH MODELS VARYING QUITE A BIT BETWEEN LATE SUNDAY
NIGHT/MONDAY MORNING TO MONDAY AFTERNOON. THE COUPLED JET DIFFLUENCE
AND SFC FORCING WILL BRING A CONTINUED CHANCE FOR SHOWERS THROUGH
THE DAY...WITH PERHAPS A CLAP OF THUNDER OR TWO IN THE AFTERNOON AS
COLD AIR MOVES OVERHEAD. STILL CONCERNED ABOUT SNOW POTENTIAL ON
MONDAY...BUT IT MAINLY DEPENDS ON COLD FRONT TIMING AND TROUGH
PASSAGE SO WILL JUST KEEP SNOW FOR THE MORNING HOURS.

PRECIP WILL DECREASE FROM NORTHWEST TO SOUTHEAST MONDAY NIGHT INTO
TUESDAY AS THE SHORTWAVE TROUGH SHIFTS EAST AND A HIGH AMPLITUDE
RIDGE BUILDS IN FROM THE WEST. TEMPS WILL STEADILY WARM THROUGH THE
WEEK AS HEIGHTS RISE OVERHEAD...AND DRY CONDITIONS LOOK TO PREVAIL
FROM THE LATTER HALF OF TUESDAY THROUGH MUCH OF THURSDAY. THE RIDGE
WILL THEN MOVE EAST ON THURSDAY THROUGH FRIDAY ALLOWING A FETCH OF
PACIFIC MOISTURE TO OVERSPREAD THE CWA IN INCREASING SOUTHWEST FLOW
ALOFT. THUS...EXPECTING A RETURN OF SHOWERS AND T-STORMS FOR
THURSDAY AFTERNOON AND AGAIN ON FRIDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1201 PM MDT FRI APR 24 2015

SHOWERS ARE DEVELOPING ALONG THE I-80 CORRIDOR THIS MORNING WITH A
FEW T-STORMS OBSERVED OVER THE SNOWY RANGE. EXPECT THIS ACTIVITY
TO EXPAND IN COVERAGE EASTWARD THROUGH THE AFTERNOON AS A WEAK
FRONT DROPS SOUTH AND STALLS ACROSS THE EASTERN PLAINS IN THE
AFTERNOON AND EVENING. COVERAGE STILL LOOKS TO BE ON THE WIDELY
SCATTERED SIDE SO LEFT VCTS AT MOST TERMINALS FOR NOW AND WILL
UPDATE AS NEEDED. CONVECTION WILL WANE THIS EVENING WITH LIGHT
WINDS EXPECTED OVERNIGHT. NORTH-NORTHEAST FLOW IN THE LOW LEVELS
COULD BRING MVFR CIGS TO KCDR LATE TONIGHT...WITH SREF GUIDANCE
SUGGESTING THE 10-16Z OR SO TIMEFRAME. OTHERWISE...VFR CONDITIONS
ARE EXPECTED ELSEWHERE.


&&

.FIRE WEATHER...
ISSUED AT 155 PM MDT FRI APR 24 2015

LIGHTNING STRIKES WILL BE POSSIBLE THIS EVENING AS THE STORMS MOVE
INTO DAWES AND SIOUX COUNTIES THIS EVENING. THESE LIGHTNING
STRIKES MAY HELP IGNITE A FIRE OR TWO ESPECIALLY WHERE THE PRECIP.
DID NOT FALL LAST WEEK AND LACK OF GREENUP. OTHERWISE...LITTLE OR
NO FIRE WEATHER CONCERNS ARE EXPECTED THIS WEEKEND DUE TO THE
POTENTIAL FOR MORE PRECIPITATION.

&&

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

$$

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



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