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000
FXUS65 KCYS 192156
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
255 PM MST FRI DEC 19 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 300 PM MST FRI DEC 19 2014

GENERALLY QUIET WEATHER EXPECTED TONIGHT AND SATURDAY WITH JUST
SOME SNOW SHOWERS OCCURRING OVER THE HIGHER MTNS AT TIMES AS WEAK
RIPPLES IN GENERALLY WNWLY FLOW PASS BY WITH ACCOMPANYING ENHANCED
MOISTURE RIDING UP WEST-FACING SLOPES. CHANGES ENSUE ON SUNDAY AS
JET ENERGY RIDES OFF THE PACIFIC NW AND TURNS SE OVER THE REGION
WHILE SFC PRESSURE FALLS OCCUR OVER THE HIGH PLAINS...SETTING UP A
FAVORABLE WIND PATTERN IN WIND-PRONE AREAS. AT THE SAME TIME
INCREASING MOISTURE WILL RIDE UP THE MOUNTAINS LATE SUNDAY
INCREASING SNOWFALL. AS A RESULT CURRENT HILITES LOOK TO BE IN
GOOD SHAPE AND WILL NOT ALTER AT THIS TIME. MILD TEMPS OVER THE
PLAINS SUNDAY WITH DOWNSLOPING FLOW WITH MAXS APPROACHING 50F IN A
FEW AREAS.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 PM MST FRI DEC 19 2014

SUNDAY NIGHT...POTENT SHORTWAVE TROUGH...ALBERTA CLIPPER
SYSTEM...MOVES SOUTHEAST ACROSS THE DAKOTAS...SENDING A COLD FRONT
ACROSS OUR COUNTIES AND CRANKING UP OUR WINDS. DEEP MOISTURE IN
NORTHWEST FLOW ALOFT WILL KEEP THE OROGRAPHIC SNOW MACHINE CRANKING
ACROSS THE SNOWY AND SIERRA MADRE RANGES WITH A CHANCE OF SNOW
ELSEWHERE IN CYCLONIC FLOW ALOFT.

MONDAY...IF YOU LOVE WINDY...COLD WEATHER...YOU WILL ENJOY THIS DAY
AS BRISK NORTHWEST FLOW FROM THE SURFACE TO 500 MB PREVAILS. BASED
ON THE 700 MB GRADIENTS AND DEEP COLD AIR ADVECTION...WE MAY NEED
HIGH WIND WARNINGS ACROSS MUCH OF SOUTHEAST WYOMING...ESPECIALLY
OVER OUR WIND PRONE LOCALES SUCH AS ARLINGTON...VEDAUWOO AND THE
SUMMIT OF INTERSTATE 80...ALONG WITH WIND ADVISORIES OVER WESTERN
NEBRASKA. OROGRAPHIC SNOWS WILL DECREASE IN COVERAGE OVER THE SNOWY
AND SIERRA MADRE RANGES AS MOISTURE WANES SLIGHTLY.

TUESDAY...WILL BE A GOOD TRAVEL DAY FOR THE PRE CHRISTMAS TRAVEL
PERIOD. PRIMARY ISSUE WILL BE WINDS AS THE 700 MB GRADIENTS SUGGEST
A TYPICALLY WINDY DAY...WITH PERHAPS OUR WIND PRONE LOCALES SUCH AS
ARLINGTON...VEDAUWOO...BORDEAUX AND THE INTERSTATE 80 SUMMIT
APPROACHING HIGH WIND CRITERIA. ONLY SNOW EXPECTED WILL BE OVER THE
SNOWY AND SIERRA MADRE RANGES...AND ONLY SCATTERED SNOW
SHOWERS...DRY ELSEWHERE.

CHRISTMAS EVE DAY...ANOTHER GOOD TRAVEL DAY FOR THE PRE CHRISTMAS
TRAVEL AS THE FLOW ALOFT BACKS TO NORTHWEST WITH A TRANSITORY FAST
MOVING SHORTWAVE RIDGE OVERHEAD. ASIDE FROM A FEW MOUNTAIN SNOW
SHOWERS OVER THE SNOWY...SIERRA MADRE AND NORTHERN LARAMIE
RANGES...NO PRECIPITATION EXPECTED. WILL BE A WARMER AND WINDY DAY
BASED ON PROJECTED GRADIENTS...BUT MINIMAL TRAVEL ISSUES.

CHRISTMAS...IF YOU LOVE SEEING SNOW ON CHRISTMAS DAY...YOU MAY BE
PLEASED. WHILE THE TYPICALLY DRIER GFS KEEPS CHRISTMAS EVE MORNING
DRY WITH THE APPROACHING SHORTWAVE TROUGH OVER IDAHO...THE
ECMWF...TYPICALLY PERFORMING BETTER IN THE WINTER...SHOWS A MORE
WELL PRONOUNCED SHORTWAVE TROUGH ALOFT APPROACHING FROM IDAHO WITH
SNOW SPREADING INTO OUR WESTERN COUNTIES WEST OF A DOUGLAS TO
LARAMIE LINE BY CHRISTMAS DAY DAWN...AND WILL GO WITH THIS SOLUTION
WHICH BLENDS WELL WITH OUR SURROUNDING OFFICES.

FOR THE DAYLIGHT HOURS ON CHRISTMAS...THE ECMWF CONTINUES TO MOVE
THE WELL PRONOUNCED SHORTWAVE TROUGH ALOFT OVER WYOMING WITH A
DECENT ARCTIC INTRUSION COLD FRONT AND WIDESPREAD SNOW BY LATE
AFTERNOON WEST OF A CHEYENNE TO CHADRON LINE...WHEREAS THE GFS IS
LESS BULLISH WITH QPF AND SNOWFALL AND BRINGS THE COLD FRONT IN
LATER IN THE DAY. SINCE THE ECMWF TYPICALLY OUTPERFORMS THE MORE
OFTEN DRIER GFS IN THE WINTER...AND SINCE THE ECMWF SOLUTION IS
CLOSE TO THE ONE FROM YESTERDAY...ALBEIT A TAD SLOWER...WILL SIDE
WITH OUR SURROUNDING OFFICES AND PAINT AT LEAST A CHANCE OF
AFTERNOON SNOW ACROSS MOST OF OUR COUNTIES...WITH WIDESPREAD
OROGRAPHIC SNOWS ACROSS OUR NORTHERN LARAMIE...SNOWY AND SIERRA
MADRE RANGES.

FRIDAY...LOOKS LIKE ANOTHER DECENT TRAVEL DAY AS BOTH THE GFS AND
ECMWF SHOW THE SHORTWAVE TROUGH ALOFT MOVING TO THE EAST OF OUR
FORECAST AREA...WITH DECREASING CHANCES FOR SNOW...AND WINDY AND
COLD CONDITIONS PER PROGGED GRADIENTS AND THICKNESSES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1040 AM MST FRI DEC 19 2014

THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR
SOME MORE PATCHY FOG AROUND THE BFF TAF SITE. OTHERWISE...VFR
CONDITIONS ARE EXPECTED ACROSS THE REMAINDER OF THE TAF
SITES...DUE TO THE INFLUENCE OF SURFACE HIGH PRESSURE SITUATED
OVER SOUTHERN WYOMING. THERE MAY BE A WIND SHIFT AT THE CDR TAF
SITE LATE IN THE PERIOD AS A WEAK DISTURBANCE IN NORTHERN MONTANA
MOVES INTO THE NORTHERN PLAINS.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MST FRI DEC 19 2014

INCREASING WINDS AROUND THE MOUNTAINS WILL BE THE MAIN CONCERN
OVER THE WEEKEND BUT OTHER FACTORS EXPECTED TO BE NON-CRITICAL.
SNOW SHOWERS WILL INCREASE OVER THE MTNS BEGINNING SUNDAY AND
PERSIST INTO EARLY NEXT WEEK. ELSEWHERE MAINLY DRY AND COOL
WEATHER WILL CONTINUE.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     AFTERNOON FOR WYZ112-114.

     HIGH WIND WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY EVENING
     FOR WYZ106-110.

     HIGH WIND WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR
     WYZ116-117.

NE...NONE.
&&

$$

SHORT TERM...RE
LONG TERM...RUBIN
AVIATION...REC
FIRE WEATHER...RE





000
FXUS65 KCYS 191745
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1045 AM MST FRI DEC 19 2014

.SHORT TERM...(TODAY AND SUNDAY NIGHT)
ISSUED AT 400 MST FRI DEC 19 2014

SHORTWAVE ENERGY EMBEDDED WITHIN NORTHWEST FLOW MOVING THRU WYOMING
EARLY THIS MORNING HAS BEEN DOING LITTLE MORE THAN BOOSTING WIND
GUSTS TO 35-45 MPH THRU THE WIND CORRIDOR AND PRODUCING SOME LIGHT
SNOW IN THE SNOWY/SIERRA MADRES. THIS SHORTWAVE WILL DEPART THE AREA
BY EARLY AFTERNOON ALLOWING FOR A WEAKENING TRANSITORY RIDGE
TONIGHT. CLOUDS SHOULD REMAIN TUCKED CLOSE TO THE HIER TERRAIN
TODAY...WITH MOSTLY/PARTLY SUNNY SKIES ELSEWHERE. BREEZY CONDITIONS
WILL RETURN TODAY AS WELL IN AND AROUND THE SOUTHEAST WYOMING
MOUNTAINS AND ADJACENT PLAINS. THE GOOD NEWS IS THAT THESE WINDS
SHOULD BOOST TEMPS A FEW DEGREES IN THE IMMEDIATE LEE...LIKELY INTO
THE LOWER 40S TODAY.

THE PATTERN TURNS WEST/NORTHWEST AND STRENGTHENS ON SATURDAY AS A
180+ KNOT ZONAL JET PLOWS INTO THE PACNW. ALTHOUGH THE CWFA WILL
REMAIN GENERALLY DRY FOR SATURDAY...SNOW CHANCES WILL BEGIN RAMP UP
OVER THE SNOWY/SIERRA MADRES AS THE PACIFIC MOISTURE FETCH BEGINS TO
BE TAPPED. ANOTHER BREEZY DAY CAN BE EXPECTED ON SATURDAY...WHICH
WILL AGAIN HELP BOOST HIGHS INTO THE LOW/MID 40S OUT ON THE ERN
PLAINS.

IMPACTS WILL BEGIN TO BECOME MORE APPARENT LATE SATURDAY NIGHT AND
DURING THE DAY ON SUNDAY AS THE WIND MACHINE AND THE BEGINNING OF A
LONG DURATION MOUNTAIN SNOW EVENT ENSUES. LETS FOCUS ON THE WIND
IMPACTS FIRST. LLVL KCAG-KCPR GRADIENTS INCREASE ABOVE CRITICAL
THRESHOLDS BEGINNING AROUND 09Z SUNDAY CONTINUING THRU THE DAY.
PROGD AXIS OF LLVL SUBSIDENCE WILL IMPACT THE WIND CORRIDOR. SO HAVE
OPTED TO ISSUE A HIGH WIND WATCH EFFECTIVE FOR ARLINGTON/BORDEAUX
07Z 12/21 THRU 07Z 12/22. INCLUDED THE SRN LARAMIE RANGE 16Z 12/21
THRU 07Z 12/22. THE OTHER IMPACT THAT WILL BEGIN TO BE FELT LATE
SATURDAY NIGHT AND MORESO DURING THE DAY ON SUNDAY AND SUNDAY WILL
BE A SIGNIFICANT SNOW EVENT FOR THE WEST SLOPE. MODELS ARE VERY
CONSISTENT IN 40-50 KNOTS OF LLVL WEST FLOW ADVECTING COPIOUS
AMOUNTS OF PACIFIC MOISTURE INTO THE SNOWY/SIERRA MADRE RANGES.
WOULD NOT AT ALL BE SURPRISED TO SEE 1-2 FEET OR MORE OF SNOW IN
THOSE AREAS LATE SATURDAY NIGHT THROUGH THE DAY ON MONDAY. HIGH
TEMPERATURES WILL AGAIN IN THE 30S WEST OF THE LARAMIE RANGE ON
SUNDAY...WITH 40S EAST.

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 400 AM MST FRI DEC 19 2014

WITH MOIST NORTHWESTERLY FLOW ALOFT IN PLACE ON MON AND THE UPPER
LEVEL JET TO THE WEST OF THE CWA...SNOW WILL CONTINUE ACROSS THE
SIERRA MADRE AND SNOWY RANGES. COULD ALSO SEE A BRIEF SHOT OF
LIGHT SNOW OVER LOWER ELEVATIONS BEHIND A MON MORNING COLD FRONT.
WINDY CONDITIONS WILL SPREAD ACROSS THE PLAINS INCLUDING THE
WESTERN NEBRASKA PANHANDLE ON MON WITH STEEPENING LLVL LAPSE RATES
AND COLD AIR ADVECTION. THE GFS IS STRONGER WITH THE WINDS ALOFT
BUT ALL MODELS SHOW GOOD LLVL MIXING. PRECIP WILL COME TO AN END
ACROSS THE MTNS BY TUES MORNING AS THE JET SHIFTS EASTWARD AND
DRYING OCCURS. TRANSITORY RIDGE MOVES OVERHEAD FOR WED.  IT WILL
BE CHILLY EARLY NEXT WEEK ESPECIALLY WHEN YOU FACTOR IN THE
WIND...WITH SLIGHT WARMING BY WED.

ATTENTION THEN TURNS TO THE LONGWAVE TROUGH THAT IS PROGGED TO
DROP SOUTHEASTWARD FROM THE PACIFIC NW INTO THE INTERMOUNTAIN WEST
BY LATE WED INTO THURS. THE GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT AND SHOW THE TROUGH AXIS NEAR UTAH BY 18Z THURS. UPPER
LEVEL DIVERGENCE AND LARGE SCALE ASCENT WOULD SPREAD ACROSS THE
CWA BY THURS AFTN INTO THURS NIGHT. PRECIP DEVELOPS BEHIND THE
FROPA AND MODELS ARE CURRENTLY SHOWING WIDESPREAD QPF AMOUNTS OF
0.2-0.5 INCHES. IT IS A RATHER PROGRESSIVE SYSTEM WITH SNOW COMING
TO AN END BY FRI MORNING. WILL CONTINUE TO MONITOR THE EVOLUTION
OF THIS SYSTEM WITH THE HOLIDAY APPROACHING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1040 AM MST FRI DEC 19 2014

THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR
SOME MORE PATCHY FOG AROUND THE BFF TAF SITE. OTHERWISE...VFR
CONDITIONS ARE EXPECTED ACROSS THE REMAINDER OF THE TAF
SITES...DUE TO THE INFLUENCE OF SURFACE HIGH PRESSURE SITUATED
OVER SOUTHERN WYOMING. THERE MAY BE A WIND SHIFT AT THE CDR TAF
SITE LATE IN THE PERIOD AS A WEAK DISTURBANCE IN NORTHERN MONTANA
MOVES INTO THE NORTHERN PLAINS.

&&

.FIRE WEATHER...
ISSUED AT 350 AM MST FRI DEC 19 2014

NO FIRE WEATHER CONCERNS THROUGH THE PERIOD. BREEZY BUT GENERALLY
DRY CONDITIONS WILL CONTINUE ACROSS THE DISTRICTS TODAY AND
TOMORROW. HIGH TEMPERATURES WILL REACH THE 30S AT MOST PLACES WITH
SOME 40S OUT ON THE EASTERN PLAINS. WINDY CONDITIONS AND
SIGNIFICANT MOUNTAIN SNOW ACCUMULATIONS RETURN BEGINNING SATURDAY
NIGHT AND CONTINUING INTO EARLY NEXT WEEK. HIGH WIND WATCHES HAVE
BEEN POSTED FOR PORTIONS OF SOUTHEAST WYOMING. MEANWHILE...WINTER
STORM WATCHES HAVE BEEN ISSUED FOR THE SNOWY AND SIERRA MADRE
RANGES WHERE 1 TO 2 FEET OF SNOW WILL BE POSSIBLE.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     AFTERNOON FOR WYZ112-114.

     HIGH WIND WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY EVENING
     FOR WYZ106-110.

     HIGH WIND WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR
     WYZ116-117.

NE...NONE.
&&

$$

SHORT TERM...CAH
LONG TERM...ZF
AVIATION...REC
FIRE WEATHER...CAH




000
FXUS65 KCYS 191745
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1045 AM MST FRI DEC 19 2014

.SHORT TERM...(TODAY AND SUNDAY NIGHT)
ISSUED AT 400 MST FRI DEC 19 2014

SHORTWAVE ENERGY EMBEDDED WITHIN NORTHWEST FLOW MOVING THRU WYOMING
EARLY THIS MORNING HAS BEEN DOING LITTLE MORE THAN BOOSTING WIND
GUSTS TO 35-45 MPH THRU THE WIND CORRIDOR AND PRODUCING SOME LIGHT
SNOW IN THE SNOWY/SIERRA MADRES. THIS SHORTWAVE WILL DEPART THE AREA
BY EARLY AFTERNOON ALLOWING FOR A WEAKENING TRANSITORY RIDGE
TONIGHT. CLOUDS SHOULD REMAIN TUCKED CLOSE TO THE HIER TERRAIN
TODAY...WITH MOSTLY/PARTLY SUNNY SKIES ELSEWHERE. BREEZY CONDITIONS
WILL RETURN TODAY AS WELL IN AND AROUND THE SOUTHEAST WYOMING
MOUNTAINS AND ADJACENT PLAINS. THE GOOD NEWS IS THAT THESE WINDS
SHOULD BOOST TEMPS A FEW DEGREES IN THE IMMEDIATE LEE...LIKELY INTO
THE LOWER 40S TODAY.

THE PATTERN TURNS WEST/NORTHWEST AND STRENGTHENS ON SATURDAY AS A
180+ KNOT ZONAL JET PLOWS INTO THE PACNW. ALTHOUGH THE CWFA WILL
REMAIN GENERALLY DRY FOR SATURDAY...SNOW CHANCES WILL BEGIN RAMP UP
OVER THE SNOWY/SIERRA MADRES AS THE PACIFIC MOISTURE FETCH BEGINS TO
BE TAPPED. ANOTHER BREEZY DAY CAN BE EXPECTED ON SATURDAY...WHICH
WILL AGAIN HELP BOOST HIGHS INTO THE LOW/MID 40S OUT ON THE ERN
PLAINS.

IMPACTS WILL BEGIN TO BECOME MORE APPARENT LATE SATURDAY NIGHT AND
DURING THE DAY ON SUNDAY AS THE WIND MACHINE AND THE BEGINNING OF A
LONG DURATION MOUNTAIN SNOW EVENT ENSUES. LETS FOCUS ON THE WIND
IMPACTS FIRST. LLVL KCAG-KCPR GRADIENTS INCREASE ABOVE CRITICAL
THRESHOLDS BEGINNING AROUND 09Z SUNDAY CONTINUING THRU THE DAY.
PROGD AXIS OF LLVL SUBSIDENCE WILL IMPACT THE WIND CORRIDOR. SO HAVE
OPTED TO ISSUE A HIGH WIND WATCH EFFECTIVE FOR ARLINGTON/BORDEAUX
07Z 12/21 THRU 07Z 12/22. INCLUDED THE SRN LARAMIE RANGE 16Z 12/21
THRU 07Z 12/22. THE OTHER IMPACT THAT WILL BEGIN TO BE FELT LATE
SATURDAY NIGHT AND MORESO DURING THE DAY ON SUNDAY AND SUNDAY WILL
BE A SIGNIFICANT SNOW EVENT FOR THE WEST SLOPE. MODELS ARE VERY
CONSISTENT IN 40-50 KNOTS OF LLVL WEST FLOW ADVECTING COPIOUS
AMOUNTS OF PACIFIC MOISTURE INTO THE SNOWY/SIERRA MADRE RANGES.
WOULD NOT AT ALL BE SURPRISED TO SEE 1-2 FEET OR MORE OF SNOW IN
THOSE AREAS LATE SATURDAY NIGHT THROUGH THE DAY ON MONDAY. HIGH
TEMPERATURES WILL AGAIN IN THE 30S WEST OF THE LARAMIE RANGE ON
SUNDAY...WITH 40S EAST.

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 400 AM MST FRI DEC 19 2014

WITH MOIST NORTHWESTERLY FLOW ALOFT IN PLACE ON MON AND THE UPPER
LEVEL JET TO THE WEST OF THE CWA...SNOW WILL CONTINUE ACROSS THE
SIERRA MADRE AND SNOWY RANGES. COULD ALSO SEE A BRIEF SHOT OF
LIGHT SNOW OVER LOWER ELEVATIONS BEHIND A MON MORNING COLD FRONT.
WINDY CONDITIONS WILL SPREAD ACROSS THE PLAINS INCLUDING THE
WESTERN NEBRASKA PANHANDLE ON MON WITH STEEPENING LLVL LAPSE RATES
AND COLD AIR ADVECTION. THE GFS IS STRONGER WITH THE WINDS ALOFT
BUT ALL MODELS SHOW GOOD LLVL MIXING. PRECIP WILL COME TO AN END
ACROSS THE MTNS BY TUES MORNING AS THE JET SHIFTS EASTWARD AND
DRYING OCCURS. TRANSITORY RIDGE MOVES OVERHEAD FOR WED.  IT WILL
BE CHILLY EARLY NEXT WEEK ESPECIALLY WHEN YOU FACTOR IN THE
WIND...WITH SLIGHT WARMING BY WED.

ATTENTION THEN TURNS TO THE LONGWAVE TROUGH THAT IS PROGGED TO
DROP SOUTHEASTWARD FROM THE PACIFIC NW INTO THE INTERMOUNTAIN WEST
BY LATE WED INTO THURS. THE GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT AND SHOW THE TROUGH AXIS NEAR UTAH BY 18Z THURS. UPPER
LEVEL DIVERGENCE AND LARGE SCALE ASCENT WOULD SPREAD ACROSS THE
CWA BY THURS AFTN INTO THURS NIGHT. PRECIP DEVELOPS BEHIND THE
FROPA AND MODELS ARE CURRENTLY SHOWING WIDESPREAD QPF AMOUNTS OF
0.2-0.5 INCHES. IT IS A RATHER PROGRESSIVE SYSTEM WITH SNOW COMING
TO AN END BY FRI MORNING. WILL CONTINUE TO MONITOR THE EVOLUTION
OF THIS SYSTEM WITH THE HOLIDAY APPROACHING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1040 AM MST FRI DEC 19 2014

THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR
SOME MORE PATCHY FOG AROUND THE BFF TAF SITE. OTHERWISE...VFR
CONDITIONS ARE EXPECTED ACROSS THE REMAINDER OF THE TAF
SITES...DUE TO THE INFLUENCE OF SURFACE HIGH PRESSURE SITUATED
OVER SOUTHERN WYOMING. THERE MAY BE A WIND SHIFT AT THE CDR TAF
SITE LATE IN THE PERIOD AS A WEAK DISTURBANCE IN NORTHERN MONTANA
MOVES INTO THE NORTHERN PLAINS.

&&

.FIRE WEATHER...
ISSUED AT 350 AM MST FRI DEC 19 2014

NO FIRE WEATHER CONCERNS THROUGH THE PERIOD. BREEZY BUT GENERALLY
DRY CONDITIONS WILL CONTINUE ACROSS THE DISTRICTS TODAY AND
TOMORROW. HIGH TEMPERATURES WILL REACH THE 30S AT MOST PLACES WITH
SOME 40S OUT ON THE EASTERN PLAINS. WINDY CONDITIONS AND
SIGNIFICANT MOUNTAIN SNOW ACCUMULATIONS RETURN BEGINNING SATURDAY
NIGHT AND CONTINUING INTO EARLY NEXT WEEK. HIGH WIND WATCHES HAVE
BEEN POSTED FOR PORTIONS OF SOUTHEAST WYOMING. MEANWHILE...WINTER
STORM WATCHES HAVE BEEN ISSUED FOR THE SNOWY AND SIERRA MADRE
RANGES WHERE 1 TO 2 FEET OF SNOW WILL BE POSSIBLE.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     AFTERNOON FOR WYZ112-114.

     HIGH WIND WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY EVENING
     FOR WYZ106-110.

     HIGH WIND WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR
     WYZ116-117.

NE...NONE.
&&

$$

SHORT TERM...CAH
LONG TERM...ZF
AVIATION...REC
FIRE WEATHER...CAH





000
FXUS65 KCYS 191111
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
411 AM MST FRI DEC 19 2014

.SHORT TERM...(TODAY AND SUNDAY NIGHT)
ISSUED AT 400 MST FRI DEC 19 2014

SHORTWAVE ENERGY EMBEDDED WITHIN NORTHWEST FLOW MOVING THRU WYOMING
EARLY THIS MORNING HAS BEEN DOING LITTLE MORE THAN BOOSTING WIND
GUSTS TO 35-45 MPH THRU THE WIND CORRIDOR AND PRODUCING SOME LIGHT
SNOW IN THE SNOWY/SIERRA MADRES. THIS SHORTWAVE WILL DEPART THE AREA
BY EARLY AFTERNOON ALLOWING FOR A WEAKENING TRANSITORY RIDGE
TONIGHT. CLOUDS SHOULD REMAIN TUCKED CLOSE TO THE HIER TERRAIN
TODAY...WITH MOSTLY/PARTLY SUNNY SKIES ELSEWHERE. BREEZY CONDITIONS
WILL RETURN TODAY AS WELL IN AND AROUND THE SOUTHEAST WYOMING
MOUNTAINS AND ADJACENT PLAINS. THE GOOD NEWS IS THAT THESE WINDS
SHOULD BOOST TEMPS A FEW DEGREES IN THE IMMEDIATE LEE...LIKELY INTO
THE LOWER 40S TODAY.

THE PATTERN TURNS WEST/NORTHWEST AND STRENGTHENS ON SATURDAY AS A
180+ KNOT ZONAL JET PLOWS INTO THE PACNW. ALTHOUGH THE CWFA WILL
REMAIN GENERALLY DRY FOR SATURDAY...SNOW CHANCES WILL BEGIN RAMP UP
OVER THE SNOWY/SIERRA MADRES AS THE PACIFIC MOISTURE FETCH BEGINS TO
BE TAPPED. ANOTHER BREEZY DAY CAN BE EXPECTED ON SATURDAY...WHICH
WILL AGAIN HELP BOOST HIGHS INTO THE LOW/MID 40S OUT ON THE ERN
PLAINS.

IMPACTS WILL BEGIN TO BECOME MORE APPARENT LATE SATURDAY NIGHT AND
DURING THE DAY ON SUNDAY AS THE WIND MACHINE AND THE BEGINNING OF A
LONG DURATION MOUNTAIN SNOW EVENT ENSUES. LETS FOCUS ON THE WIND
IMPACTS FIRST. LLVL KCAG-KCPR GRADIENTS INCREASE ABOVE CRITICAL
THRESHOLDS BEGINNING AROUND 09Z SUNDAY CONTINUING THRU THE DAY.
PROGD AXIS OF LLVL SUBSIDENCE WILL IMPACT THE WIND CORRIDOR. SO HAVE
OPTED TO ISSUE A HIGH WIND WATCH EFFECTIVE FOR ARLINGTON/BORDEAUX
07Z 12/21 THRU 07Z 12/22. INCLUDED THE SRN LARAMIE RANGE 16Z 12/21
THRU 07Z 12/22. THE OTHER IMPACT THAT WILL BEGIN TO BE FELT LATE
SATURDAY NIGHT AND MORESO DURING THE DAY ON SUNDAY AND SUNDAY WILL
BE A SIGNIFICANT SNOW EVENT FOR THE WEST SLOPE. MODELS ARE VERY
CONSISTENT IN 40-50 KNOTS OF LLVL WEST FLOW ADVECTING COPIOUS
AMOUNTS OF PACIFIC MOISTURE INTO THE SNOWY/SIERRA MADRE RANGES.
WOULD NOT AT ALL BE SURPRISED TO SEE 1-2 FEET OR MORE OF SNOW IN
THOSE AREAS LATE SATURDAY NIGHT THROUGH THE DAY ON MONDAY. HIGH
TEMPERATURES WILL AGAIN IN THE 30S WEST OF THE LARAMIE RANGE ON
SUNDAY...WITH 40S EAST.

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 400 AM MST FRI DEC 19 2014

WITH MOIST NORTHWESTERLY FLOW ALOFT IN PLACE ON MON AND THE UPPER
LEVEL JET TO THE WEST OF THE CWA...SNOW WILL CONTINUE ACROSS THE
SIERRA MADRE AND SNOWY RANGES. COULD ALSO SEE A BRIEF SHOT OF
LIGHT SNOW OVER LOWER ELEVATIONS BEHIND A MON MORNING COLD FRONT.
WINDY CONDITIONS WILL SPREAD ACROSS THE PLAINS INCLUDING THE
WESTERN NEBRASKA PANHANDLE ON MON WITH STEEPENING LLVL LAPSE RATES
AND COLD AIR ADVECTION. THE GFS IS STRONGER WITH THE WINDS ALOFT
BUT ALL MODELS SHOW GOOD LLVL MIXING. PRECIP WILL COME TO AN END
ACROSS THE MTNS BY TUES MORNING AS THE JET SHIFTS EASTWARD AND
DRYING OCCURS. TRANSITORY RIDGE MOVES OVERHEAD FOR WED.  IT WILL
BE CHILLY EARLY NEXT WEEK ESPECIALLY WHEN YOU FACTOR IN THE
WIND...WITH SLIGHT WARMING BY WED.

ATTENTION THEN TURNS TO THE LONGWAVE TROUGH THAT IS PROGGED TO
DROP SOUTHEASTWARD FROM THE PACIFIC NW INTO THE INTERMOUNTAIN WEST
BY LATE WED INTO THURS. THE GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT AND SHOW THE TROUGH AXIS NEAR UTAH BY 18Z THURS. UPPER
LEVEL DIVERGENCE AND LARGE SCALE ASCENT WOULD SPREAD ACROSS THE
CWA BY THURS AFTN INTO THURS NIGHT. PRECIP DEVELOPS BEHIND THE
FROPA AND MODELS ARE CURRENTLY SHOWING WIDESPREAD QPF AMOUNTS OF
0.2-0.5 INCHES. IT IS A RATHER PROGRESSIVE SYSTEM WITH SNOW COMING
TO AN END BY FRI MORNING. WILL CONTINUE TO MONITOR THE EVOLUTION
OF THIS SYSTEM WITH THE HOLIDAY APPROACHING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 400 AM MST FRI DEC 19 2014

VFR CONDITIONS THROUGH THE TAF PERIOD. WEST WINDS WILL INCREASE BY
LATE MORNING ACROSS SOUTHEAST WY AND WILL REMAIN BREEZY THROUGH
THE AFTERNOON WITH OCCASIONAL GUSTS TO 25-30 MPH. THE WINDS WILL
THEN COME DOWN SOMEWHAT AFTER SUNSET. CLOUD COVER WILL BE LIMITED
TO MAINLY PASSING HIGH CLOUDS.

&&

.FIRE WEATHER...
ISSUED AT 350 AM MST FRI DEC 19 2014

NO FIRE WEATHER CONCERNS THROUGH THE PERIOD. BREEZY BUT GENERALLY
DRY CONDITIONS WILL CONTINUE ACROSS THE DISTRICTS TODAY AND
TOMORROW. HIGH TEMPERATURES WILL REACH THE 30S AT MOST PLACES WITH
SOME 40S OUT ON THE EASTERN PLAINS. WINDY CONDITIONS AND
SIGNIFICANT MOUNTAIN SNOW ACCUMULATIONS RETURN BEGINNING SATURDAY
NIGHT AND CONTINUING INTO EARLY NEXT WEEK. HIGH WIND WATCHES HAVE
BEEN POSTED FOR PORTIONS OF SOUTHEAST WYOMING. MEANWHILE...WINTER
STORM WATCHES HAVE BEEN ISSUED FOR THE SNOWY AND SIERRA MADRE
RANGES WHERE 1 TO 2 FEET OF SNOW WILL BE POSSIBLE.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     AFTERNOON FOR WYZ112-114.

     HIGH WIND WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY EVENING
     FOR WYZ106-110.

     HIGH WIND WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR
     WYZ116-117.

NE...NONE.
&&

$$

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





000
FXUS65 KCYS 191111
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
411 AM MST FRI DEC 19 2014

.SHORT TERM...(TODAY AND SUNDAY NIGHT)
ISSUED AT 400 MST FRI DEC 19 2014

SHORTWAVE ENERGY EMBEDDED WITHIN NORTHWEST FLOW MOVING THRU WYOMING
EARLY THIS MORNING HAS BEEN DOING LITTLE MORE THAN BOOSTING WIND
GUSTS TO 35-45 MPH THRU THE WIND CORRIDOR AND PRODUCING SOME LIGHT
SNOW IN THE SNOWY/SIERRA MADRES. THIS SHORTWAVE WILL DEPART THE AREA
BY EARLY AFTERNOON ALLOWING FOR A WEAKENING TRANSITORY RIDGE
TONIGHT. CLOUDS SHOULD REMAIN TUCKED CLOSE TO THE HIER TERRAIN
TODAY...WITH MOSTLY/PARTLY SUNNY SKIES ELSEWHERE. BREEZY CONDITIONS
WILL RETURN TODAY AS WELL IN AND AROUND THE SOUTHEAST WYOMING
MOUNTAINS AND ADJACENT PLAINS. THE GOOD NEWS IS THAT THESE WINDS
SHOULD BOOST TEMPS A FEW DEGREES IN THE IMMEDIATE LEE...LIKELY INTO
THE LOWER 40S TODAY.

THE PATTERN TURNS WEST/NORTHWEST AND STRENGTHENS ON SATURDAY AS A
180+ KNOT ZONAL JET PLOWS INTO THE PACNW. ALTHOUGH THE CWFA WILL
REMAIN GENERALLY DRY FOR SATURDAY...SNOW CHANCES WILL BEGIN RAMP UP
OVER THE SNOWY/SIERRA MADRES AS THE PACIFIC MOISTURE FETCH BEGINS TO
BE TAPPED. ANOTHER BREEZY DAY CAN BE EXPECTED ON SATURDAY...WHICH
WILL AGAIN HELP BOOST HIGHS INTO THE LOW/MID 40S OUT ON THE ERN
PLAINS.

IMPACTS WILL BEGIN TO BECOME MORE APPARENT LATE SATURDAY NIGHT AND
DURING THE DAY ON SUNDAY AS THE WIND MACHINE AND THE BEGINNING OF A
LONG DURATION MOUNTAIN SNOW EVENT ENSUES. LETS FOCUS ON THE WIND
IMPACTS FIRST. LLVL KCAG-KCPR GRADIENTS INCREASE ABOVE CRITICAL
THRESHOLDS BEGINNING AROUND 09Z SUNDAY CONTINUING THRU THE DAY.
PROGD AXIS OF LLVL SUBSIDENCE WILL IMPACT THE WIND CORRIDOR. SO HAVE
OPTED TO ISSUE A HIGH WIND WATCH EFFECTIVE FOR ARLINGTON/BORDEAUX
07Z 12/21 THRU 07Z 12/22. INCLUDED THE SRN LARAMIE RANGE 16Z 12/21
THRU 07Z 12/22. THE OTHER IMPACT THAT WILL BEGIN TO BE FELT LATE
SATURDAY NIGHT AND MORESO DURING THE DAY ON SUNDAY AND SUNDAY WILL
BE A SIGNIFICANT SNOW EVENT FOR THE WEST SLOPE. MODELS ARE VERY
CONSISTENT IN 40-50 KNOTS OF LLVL WEST FLOW ADVECTING COPIOUS
AMOUNTS OF PACIFIC MOISTURE INTO THE SNOWY/SIERRA MADRE RANGES.
WOULD NOT AT ALL BE SURPRISED TO SEE 1-2 FEET OR MORE OF SNOW IN
THOSE AREAS LATE SATURDAY NIGHT THROUGH THE DAY ON MONDAY. HIGH
TEMPERATURES WILL AGAIN IN THE 30S WEST OF THE LARAMIE RANGE ON
SUNDAY...WITH 40S EAST.

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 400 AM MST FRI DEC 19 2014

WITH MOIST NORTHWESTERLY FLOW ALOFT IN PLACE ON MON AND THE UPPER
LEVEL JET TO THE WEST OF THE CWA...SNOW WILL CONTINUE ACROSS THE
SIERRA MADRE AND SNOWY RANGES. COULD ALSO SEE A BRIEF SHOT OF
LIGHT SNOW OVER LOWER ELEVATIONS BEHIND A MON MORNING COLD FRONT.
WINDY CONDITIONS WILL SPREAD ACROSS THE PLAINS INCLUDING THE
WESTERN NEBRASKA PANHANDLE ON MON WITH STEEPENING LLVL LAPSE RATES
AND COLD AIR ADVECTION. THE GFS IS STRONGER WITH THE WINDS ALOFT
BUT ALL MODELS SHOW GOOD LLVL MIXING. PRECIP WILL COME TO AN END
ACROSS THE MTNS BY TUES MORNING AS THE JET SHIFTS EASTWARD AND
DRYING OCCURS. TRANSITORY RIDGE MOVES OVERHEAD FOR WED.  IT WILL
BE CHILLY EARLY NEXT WEEK ESPECIALLY WHEN YOU FACTOR IN THE
WIND...WITH SLIGHT WARMING BY WED.

ATTENTION THEN TURNS TO THE LONGWAVE TROUGH THAT IS PROGGED TO
DROP SOUTHEASTWARD FROM THE PACIFIC NW INTO THE INTERMOUNTAIN WEST
BY LATE WED INTO THURS. THE GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT AND SHOW THE TROUGH AXIS NEAR UTAH BY 18Z THURS. UPPER
LEVEL DIVERGENCE AND LARGE SCALE ASCENT WOULD SPREAD ACROSS THE
CWA BY THURS AFTN INTO THURS NIGHT. PRECIP DEVELOPS BEHIND THE
FROPA AND MODELS ARE CURRENTLY SHOWING WIDESPREAD QPF AMOUNTS OF
0.2-0.5 INCHES. IT IS A RATHER PROGRESSIVE SYSTEM WITH SNOW COMING
TO AN END BY FRI MORNING. WILL CONTINUE TO MONITOR THE EVOLUTION
OF THIS SYSTEM WITH THE HOLIDAY APPROACHING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 400 AM MST FRI DEC 19 2014

VFR CONDITIONS THROUGH THE TAF PERIOD. WEST WINDS WILL INCREASE BY
LATE MORNING ACROSS SOUTHEAST WY AND WILL REMAIN BREEZY THROUGH
THE AFTERNOON WITH OCCASIONAL GUSTS TO 25-30 MPH. THE WINDS WILL
THEN COME DOWN SOMEWHAT AFTER SUNSET. CLOUD COVER WILL BE LIMITED
TO MAINLY PASSING HIGH CLOUDS.

&&

.FIRE WEATHER...
ISSUED AT 350 AM MST FRI DEC 19 2014

NO FIRE WEATHER CONCERNS THROUGH THE PERIOD. BREEZY BUT GENERALLY
DRY CONDITIONS WILL CONTINUE ACROSS THE DISTRICTS TODAY AND
TOMORROW. HIGH TEMPERATURES WILL REACH THE 30S AT MOST PLACES WITH
SOME 40S OUT ON THE EASTERN PLAINS. WINDY CONDITIONS AND
SIGNIFICANT MOUNTAIN SNOW ACCUMULATIONS RETURN BEGINNING SATURDAY
NIGHT AND CONTINUING INTO EARLY NEXT WEEK. HIGH WIND WATCHES HAVE
BEEN POSTED FOR PORTIONS OF SOUTHEAST WYOMING. MEANWHILE...WINTER
STORM WATCHES HAVE BEEN ISSUED FOR THE SNOWY AND SIERRA MADRE
RANGES WHERE 1 TO 2 FEET OF SNOW WILL BE POSSIBLE.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
     AFTERNOON FOR WYZ112-114.

     HIGH WIND WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY EVENING
     FOR WYZ106-110.

     HIGH WIND WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR
     WYZ116-117.

NE...NONE.
&&

$$

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




000
FXUS65 KCYS 190558
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1058 PM MST THU DEC 18 2014

.UPDATE...
ISSUED AT 836 PM MST THU DEC 18 2014

NO BIG CHANGES TO TONIGHTS FORECAST BUT DUE TO LIGHT WINDS AND
RADIATIONAL COOLING THERE IS SOME PATCHY FOG INTO THE WESTERN
NEBRASKA PANHANDLE. FOG IS NOT SHOWING UP ON WEB CAMS...ONLY BEING
PICKED UP AT THE BFF ASOS. MOST LIKELY THIS IS SHALLOW THIN FOG
WHICH WILL HAVE LITTLE IMPACT FOR THE TIME BEING. NOT OUT OF THE
QUESTION FOR LOCALIZED DENSE FOG LATER TONIGHT BUT GENERALLY NOT
EXPECTING MUCH IN THE WAY OF COVERAGE OR SIGNIFICANT REDUCTIONS IN
VISIBILITY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

FAIRLY QUIET WEATHER EXPECTED OVERALL THE NEXT COUPLE DAYS WITH
JUST SOME SNOW SHOWERS OVER THE HIGHER MTNS AT TIMES AS A COUPLE
WEAK SHORTWAVES PASS BY. ONE WILL SCOOT ACROSS EARLY FRIDAY WHILE
ANOTHER SWINGS ACROSS LATER SATURDAY. THESE WILL ENHANCE SNOW
SHOWERS OVER THE HIGHER MTNS AS WELL AS WINDS AROUND THE MTNS.
TEMPS WILL REMAIN ON THE COOL SIDE...BUT CLOSE TO SEASONAL
AVERAGES. ONE DIFFICULTY WILL STILL BE EFFECTS FROM GOOD SNOW
COVER OVER THE PANHANDLE...WHERE COLD AIR TRAPPING IN THE NORTH
PLATTE RIVER VALLEY KEPT TEMPS IN THE 20S TODAY. COULD BE SOME
FOG THERE AGAIN TONIGHT THOUGH A LIGHT DOWNSLOPE BREEZE WILL
HOPEFULLY LIMIT ITS THICKNESS SOME. WENT ON THE COOL SIDE FOR MAXS
THERE ON SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

SUNDAY...WINDY DAY PER PROGGED SURFACE THROUGH 700 MB GRADIENTS AND
DEEP UNIDIRECTIONAL NORTHWEST FLOW ALOFT. LONG DURATION HEAVY
SNOWFALL EVENT WILL CRANK UP OVER OUR SNOWY AND SIERRA MADRE
RANGES...AND TO A LESSER EXTENT OVER THE NORTHERN LARAMIE RANGE
BASED ON DECENT LOW AND MID LEVEL MOISTURE TRANSPORT WITH
OROGRAPHICS. WE WILL LIKELY BE ISSUING WINTER STORM WARNINGS FOR
LONG DURATION SNOWFALL EVENT OVER OUR SNOWY AND SIERRA MADRES...AND
POSSIBLY OVER THE NORTHERN LARAMIE RANGE.

MONDAY...COLD FRONT MOVES THROUGH IN STRONG NORTHWEST FLOW
ALOFT...WITH WINDY CONDITIONS PER PROGGED SURFACE THROUGH 700 MB
GRADIENTS...AND THE LONG DURATION OROGRAPHIC SNOWS WILL CONTINUE
ACROSS OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES.
ISOLATED TO SCATTERED SNOW SHOWERS ELSEWHERE IN COLD AIR ADVECTION
ALOFT.

TUESDAY...FLOW ALOFT TURNS MORE NORTHERLY WITH OROGRAPHIC SNOWS
DECREASING TO ONLY OVER THE MOUNTAINS...AND DRY ELSEWHERE DUE TO
LIMITED LOW AND MID LEVEL MOISTURE. DECENT TRAVEL PERIOD FOR
CHRISTMAS TRAVEL WITH RESPECT TO SNOWFALL ONLY OVER THE
MOUNTAINS...ALBEIT WITH TYPICALLY BRISK WINDS PRODUCING OUR TYPICAL
WINDY SEASON WINDS.

CHRISTMAS EVE DAY (WEDNESDAY)...CHANCES FOR A WHITE CHRISTMAS
EVE...AND CHRISTMAS...ARE LOOKING INCREASINGLY LIKELY...ESPECIALLY
WITH A PREFERENCE FOR THE ECMWF SOLUTION SHOWING NEXT DECENT
SHORTWAVE TROUGH ALOFT CARVING OUT OVER IDAHO WITH THE ASSOCIATED
BAND OF SNOWFALL EXTENDING ACROSS THE SOUTHERN HALF OF WYOMING BY
THE EVENING OF CHRISTMAS EVE. QPF SOLUTION ON THE GFS LOOKS TOO FAR
NORTH...AND ESPECIALLY WITH THE TYPICAL GFS DRY BIAS IN THE WINTER.

CHRISTMAS DAY...IF YOU LOVE SNOW ON CHRISTMAS DAY...YOU WILL LOVE
THE FACT THAT THE GFS AND ECMWF ARE STRIKINGLY SIMILAR IN DEPICTING
A WELL PRONOUNCED SHORTWAVE TROUGH ALOFT OVER SOUTHWEST WYOMING WITH
BOTH MODELS SHOWING A DECENT BAND OF LIGHT TO MODERATE SNOW
EXTENDING ACROSS SOUTHERN WYOMING AND NORTHERN COLORADO...WITH THE
ECMWF SLIGHTLY FURTHER NORTH WITH THE SNOW BAND OVER OUR
COUNTIES...THUS FEEL CONFIDENT ENOUGH WITH EXPERIENCE AND BOTH
MODELS CONGRUITY...TO BOOST OUR SNOWFALL POPS INTO THE 30 TO 70
PERCENT RANGE SOUTH OF A DOUGLAS TO KIMBALL LINE. IF ALL COMES
TOGETHER AS THE MODELS INDICATE...WE WILL SEE ACCUMULATING SNOW DUE
TO THE BAROCLINIC BAND...UPSLOPE AND CYCLONIC CURVATURE LIFTING
FEATURES...WITH SNOWFALL DECREASING IN AREAL COVERAGE CHRISTMAS
AFTERNOON

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1055 PM MST THU DEC 18 2014

VFR CONDITIONS THROUGH THE TAF PERIOD. WITH A STRONG LOW LEVEL
INVERSION IN PLACE ACROSS THE NORTH PLATTE VALLEY...HAVE MVFR VIS
AT BFF THROUGH MID-MORNING. WEST WINDS WILL BE BREEZY ON FRIDAY
AFTERNOON ACROSS SOUTHEAST WY WITH OCCASIONAL GUSTS TO 25-30 MPH.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MST THU DEC 18 2014

NO CONCERNS SEEN THROUGH THE WEEKEND WITH MOSTLY NON-CRITICAL
CONDITIONS. WINDS WILL INCREASE OVER THE WEEKEND BUT OTHERWISE
COOL TEMPERATURES WILL PREVAIL WITH MTN SNOW SHOWERS AT TIMES.

&&

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

$$

UPDATE...SML
SHORT TERM...RE
LONG TERM...RUBIN
AVIATION...ZF
FIRE WEATHER...RE





000
FXUS65 KCYS 190558
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1058 PM MST THU DEC 18 2014

.UPDATE...
ISSUED AT 836 PM MST THU DEC 18 2014

NO BIG CHANGES TO TONIGHTS FORECAST BUT DUE TO LIGHT WINDS AND
RADIATIONAL COOLING THERE IS SOME PATCHY FOG INTO THE WESTERN
NEBRASKA PANHANDLE. FOG IS NOT SHOWING UP ON WEB CAMS...ONLY BEING
PICKED UP AT THE BFF ASOS. MOST LIKELY THIS IS SHALLOW THIN FOG
WHICH WILL HAVE LITTLE IMPACT FOR THE TIME BEING. NOT OUT OF THE
QUESTION FOR LOCALIZED DENSE FOG LATER TONIGHT BUT GENERALLY NOT
EXPECTING MUCH IN THE WAY OF COVERAGE OR SIGNIFICANT REDUCTIONS IN
VISIBILITY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

FAIRLY QUIET WEATHER EXPECTED OVERALL THE NEXT COUPLE DAYS WITH
JUST SOME SNOW SHOWERS OVER THE HIGHER MTNS AT TIMES AS A COUPLE
WEAK SHORTWAVES PASS BY. ONE WILL SCOOT ACROSS EARLY FRIDAY WHILE
ANOTHER SWINGS ACROSS LATER SATURDAY. THESE WILL ENHANCE SNOW
SHOWERS OVER THE HIGHER MTNS AS WELL AS WINDS AROUND THE MTNS.
TEMPS WILL REMAIN ON THE COOL SIDE...BUT CLOSE TO SEASONAL
AVERAGES. ONE DIFFICULTY WILL STILL BE EFFECTS FROM GOOD SNOW
COVER OVER THE PANHANDLE...WHERE COLD AIR TRAPPING IN THE NORTH
PLATTE RIVER VALLEY KEPT TEMPS IN THE 20S TODAY. COULD BE SOME
FOG THERE AGAIN TONIGHT THOUGH A LIGHT DOWNSLOPE BREEZE WILL
HOPEFULLY LIMIT ITS THICKNESS SOME. WENT ON THE COOL SIDE FOR MAXS
THERE ON SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

SUNDAY...WINDY DAY PER PROGGED SURFACE THROUGH 700 MB GRADIENTS AND
DEEP UNIDIRECTIONAL NORTHWEST FLOW ALOFT. LONG DURATION HEAVY
SNOWFALL EVENT WILL CRANK UP OVER OUR SNOWY AND SIERRA MADRE
RANGES...AND TO A LESSER EXTENT OVER THE NORTHERN LARAMIE RANGE
BASED ON DECENT LOW AND MID LEVEL MOISTURE TRANSPORT WITH
OROGRAPHICS. WE WILL LIKELY BE ISSUING WINTER STORM WARNINGS FOR
LONG DURATION SNOWFALL EVENT OVER OUR SNOWY AND SIERRA MADRES...AND
POSSIBLY OVER THE NORTHERN LARAMIE RANGE.

MONDAY...COLD FRONT MOVES THROUGH IN STRONG NORTHWEST FLOW
ALOFT...WITH WINDY CONDITIONS PER PROGGED SURFACE THROUGH 700 MB
GRADIENTS...AND THE LONG DURATION OROGRAPHIC SNOWS WILL CONTINUE
ACROSS OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES.
ISOLATED TO SCATTERED SNOW SHOWERS ELSEWHERE IN COLD AIR ADVECTION
ALOFT.

TUESDAY...FLOW ALOFT TURNS MORE NORTHERLY WITH OROGRAPHIC SNOWS
DECREASING TO ONLY OVER THE MOUNTAINS...AND DRY ELSEWHERE DUE TO
LIMITED LOW AND MID LEVEL MOISTURE. DECENT TRAVEL PERIOD FOR
CHRISTMAS TRAVEL WITH RESPECT TO SNOWFALL ONLY OVER THE
MOUNTAINS...ALBEIT WITH TYPICALLY BRISK WINDS PRODUCING OUR TYPICAL
WINDY SEASON WINDS.

CHRISTMAS EVE DAY (WEDNESDAY)...CHANCES FOR A WHITE CHRISTMAS
EVE...AND CHRISTMAS...ARE LOOKING INCREASINGLY LIKELY...ESPECIALLY
WITH A PREFERENCE FOR THE ECMWF SOLUTION SHOWING NEXT DECENT
SHORTWAVE TROUGH ALOFT CARVING OUT OVER IDAHO WITH THE ASSOCIATED
BAND OF SNOWFALL EXTENDING ACROSS THE SOUTHERN HALF OF WYOMING BY
THE EVENING OF CHRISTMAS EVE. QPF SOLUTION ON THE GFS LOOKS TOO FAR
NORTH...AND ESPECIALLY WITH THE TYPICAL GFS DRY BIAS IN THE WINTER.

CHRISTMAS DAY...IF YOU LOVE SNOW ON CHRISTMAS DAY...YOU WILL LOVE
THE FACT THAT THE GFS AND ECMWF ARE STRIKINGLY SIMILAR IN DEPICTING
A WELL PRONOUNCED SHORTWAVE TROUGH ALOFT OVER SOUTHWEST WYOMING WITH
BOTH MODELS SHOWING A DECENT BAND OF LIGHT TO MODERATE SNOW
EXTENDING ACROSS SOUTHERN WYOMING AND NORTHERN COLORADO...WITH THE
ECMWF SLIGHTLY FURTHER NORTH WITH THE SNOW BAND OVER OUR
COUNTIES...THUS FEEL CONFIDENT ENOUGH WITH EXPERIENCE AND BOTH
MODELS CONGRUITY...TO BOOST OUR SNOWFALL POPS INTO THE 30 TO 70
PERCENT RANGE SOUTH OF A DOUGLAS TO KIMBALL LINE. IF ALL COMES
TOGETHER AS THE MODELS INDICATE...WE WILL SEE ACCUMULATING SNOW DUE
TO THE BAROCLINIC BAND...UPSLOPE AND CYCLONIC CURVATURE LIFTING
FEATURES...WITH SNOWFALL DECREASING IN AREAL COVERAGE CHRISTMAS
AFTERNOON

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1055 PM MST THU DEC 18 2014

VFR CONDITIONS THROUGH THE TAF PERIOD. WITH A STRONG LOW LEVEL
INVERSION IN PLACE ACROSS THE NORTH PLATTE VALLEY...HAVE MVFR VIS
AT BFF THROUGH MID-MORNING. WEST WINDS WILL BE BREEZY ON FRIDAY
AFTERNOON ACROSS SOUTHEAST WY WITH OCCASIONAL GUSTS TO 25-30 MPH.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MST THU DEC 18 2014

NO CONCERNS SEEN THROUGH THE WEEKEND WITH MOSTLY NON-CRITICAL
CONDITIONS. WINDS WILL INCREASE OVER THE WEEKEND BUT OTHERWISE
COOL TEMPERATURES WILL PREVAIL WITH MTN SNOW SHOWERS AT TIMES.

&&

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

$$

UPDATE...SML
SHORT TERM...RE
LONG TERM...RUBIN
AVIATION...ZF
FIRE WEATHER...RE




000
FXUS65 KCYS 190336
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
836 PM MST THU DEC 18 2014

.UPDATE...
ISSUED AT 836 PM MST THU DEC 18 2014

NO BIG CHANGES TO TONIGHTS FORECAST BUT DUE TO LIGHT WINDS AND
RADIATIONAL COOLING THERE IS SOME PATCHY FOG INTO THE WESTERN
NEBRASKA PANHANDLE. FOG IS NOT SHOWING UP ON WEB CAMS...ONLY BEING
PICKED UP AT THE BFF ASOS. MOST LIKELY THIS IS SHALLOW THIN FOG
WHICH WILL HAVE LITTLE IMPACT FOR THE TIME BEING. NOT OUT OF THE
QUESTION FOR LOCALIZED DENSE FOG LATER TONIGHT BUT GENERALLY NOT
EXPECTING MUCH IN THE WAY OF COVERAGE OR SIGNIFICANT REDUCTIONS IN
VISIBILITY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

FAIRLY QUIET WEATHER EXPECTED OVERALL THE NEXT COUPLE DAYS WITH
JUST SOME SNOW SHOWERS OVER THE HIGHER MTNS AT TIMES AS A COUPLE
WEAK SHORTWAVES PASS BY. ONE WILL SCOOT ACROSS EARLY FRIDAY WHILE
ANOTHER SWINGS ACROSS LATER SATURDAY. THESE WILL ENHANCE SNOW
SHOWERS OVER THE HIGHER MTNS AS WELL AS WINDS AROUND THE MTNS.
TEMPS WILL REMAIN ON THE COOL SIDE...BUT CLOSE TO SEASONAL
AVERAGES. ONE DIFFICULTY WILL STILL BE EFFECTS FROM GOOD SNOW
COVER OVER THE PANHANDLE...WHERE COLD AIR TRAPPING IN THE NORTH
PLATTE RIVER VALLEY KEPT TEMPS IN THE 20S TODAY. COULD BE SOME
FOG THERE AGAIN TONIGHT THOUGH A LIGHT DOWNSLOPE BREEZE WILL
HOPEFULLY LIMIT ITS THICKNESS SOME. WENT ON THE COOL SIDE FOR MAXS
THERE ON SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

SUNDAY...WINDY DAY PER PROGGED SURFACE THROUGH 700 MB GRADIENTS AND
DEEP UNIDIRECTIONAL NORTHWEST FLOW ALOFT. LONG DURATION HEAVY
SNOWFALL EVENT WILL CRANK UP OVER OUR SNOWY AND SIERRA MADRE
RANGES...AND TO A LESSER EXTENT OVER THE NORTHERN LARAMIE RANGE
BASED ON DECENT LOW AND MID LEVEL MOISTURE TRANSPORT WITH
OROGRAPHICS. WE WILL LIKELY BE ISSUING WINTER STORM WARNINGS FOR
LONG DURATION SNOWFALL EVENT OVER OUR SNOWY AND SIERRA MADRES...AND
POSSIBLY OVER THE NORTHERN LARAMIE RANGE.

MONDAY...COLD FRONT MOVES THROUGH IN STRONG NORTHWEST FLOW
ALOFT...WITH WINDY CONDITIONS PER PROGGED SURFACE THROUGH 700 MB
GRADIENTS...AND THE LONG DURATION OROGRAPHIC SNOWS WILL CONTINUE
ACROSS OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES.
ISOLATED TO SCATTERED SNOW SHOWERS ELSEWHERE IN COLD AIR ADVECTION
ALOFT.

TUESDAY...FLOW ALOFT TURNS MORE NORTHERLY WITH OROGRAPHIC SNOWS
DECREASING TO ONLY OVER THE MOUNTAINS...AND DRY ELSEWHERE DUE TO
LIMITED LOW AND MID LEVEL MOISTURE. DECENT TRAVEL PERIOD FOR
CHRISTMAS TRAVEL WITH RESPECT TO SNOWFALL ONLY OVER THE
MOUNTAINS...ALBEIT WITH TYPICALLY BRISK WINDS PRODUCING OUR TYPICAL
WINDY SEASON WINDS.

CHRISTMAS EVE DAY (WEDNESDAY)...CHANCES FOR A WHITE CHRISTMAS
EVE...AND CHRISTMAS...ARE LOOKING INCREASINGLY LIKELY...ESPECIALLY
WITH A PREFERENCE FOR THE ECMWF SOLUTION SHOWING NEXT DECENT
SHORTWAVE TROUGH ALOFT CARVING OUT OVER IDAHO WITH THE ASSOCIATED
BAND OF SNOWFALL EXTENDING ACROSS THE SOUTHERN HALF OF WYOMING BY
THE EVENING OF CHRISTMAS EVE. QPF SOLUTION ON THE GFS LOOKS TOO FAR
NORTH...AND ESPECIALLY WITH THE TYPICAL GFS DRY BIAS IN THE WINTER.

CHRISTMAS DAY...IF YOU LOVE SNOW ON CHRISTMAS DAY...YOU WILL LOVE
THE FACT THAT THE GFS AND ECMWF ARE STRIKINGLY SIMILAR IN DEPICTING
A WELL PRONOUNCED SHORTWAVE TROUGH ALOFT OVER SOUTHWEST WYOMING WITH
BOTH MODELS SHOWING A DECENT BAND OF LIGHT TO MODERATE SNOW
EXTENDING ACROSS SOUTHERN WYOMING AND NORTHERN COLORADO...WITH THE
ECMWF SLIGHTLY FURTHER NORTH WITH THE SNOW BAND OVER OUR
COUNTIES...THUS FEEL CONFIDENT ENOUGH WITH EXPERIENCE AND BOTH
MODELS CONGRUITY...TO BOOST OUR SNOWFALL POPS INTO THE 30 TO 70
PERCENT RANGE SOUTH OF A DOUGLAS TO KIMBALL LINE. IF ALL COMES
TOGETHER AS THE MODELS INDICATE...WE WILL SEE ACCUMULATING SNOW DUE
TO THE BAROCLINIC BAND...UPSLOPE AND CYCLONIC CURVATURE LIFTING
FEATURES...WITH SNOWFALL DECREASING IN AREAL COVERAGE CHRISTMAS
AFTERNOON

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 650 PM MST THU DEC 18 2014

PATCHY FOG ONCE AGAIN POSSIBLE ACROSS LOW LYING PORTIONS OF THE
NEBRASKA PANHANDLE TONIGHT. SOME PATCHY FOG AND LOW CLOUDS ALSO
POSSIBLE WEST OF THE LARAMIE RANGE IN SOUTHCENTRAL WYOMING. WINDS
WILL BE LIGHT TONIGHT AND BECOMING BREEZY FRIDAY AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 300 PM MST THU DEC 18 2014

NO CONCERNS SEEN THROUGH THE WEEKEND WITH MOSTLY NON-CRITICAL
CONDITIONS. WINDS WILL INCREASE OVER THE WEEKEND BUT OTHERWISE
COOL TEMPERATURES WILL PREVAIL WITH MTN SNOW SHOWERS AT TIMES.

&&

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

$$

UPDATE...SML
SHORT TERM...RE
LONG TERM...RUBIN
AVIATION...SML
FIRE WEATHER...RE





000
FXUS65 KCYS 190336
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
836 PM MST THU DEC 18 2014

.UPDATE...
ISSUED AT 836 PM MST THU DEC 18 2014

NO BIG CHANGES TO TONIGHTS FORECAST BUT DUE TO LIGHT WINDS AND
RADIATIONAL COOLING THERE IS SOME PATCHY FOG INTO THE WESTERN
NEBRASKA PANHANDLE. FOG IS NOT SHOWING UP ON WEB CAMS...ONLY BEING
PICKED UP AT THE BFF ASOS. MOST LIKELY THIS IS SHALLOW THIN FOG
WHICH WILL HAVE LITTLE IMPACT FOR THE TIME BEING. NOT OUT OF THE
QUESTION FOR LOCALIZED DENSE FOG LATER TONIGHT BUT GENERALLY NOT
EXPECTING MUCH IN THE WAY OF COVERAGE OR SIGNIFICANT REDUCTIONS IN
VISIBILITY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

FAIRLY QUIET WEATHER EXPECTED OVERALL THE NEXT COUPLE DAYS WITH
JUST SOME SNOW SHOWERS OVER THE HIGHER MTNS AT TIMES AS A COUPLE
WEAK SHORTWAVES PASS BY. ONE WILL SCOOT ACROSS EARLY FRIDAY WHILE
ANOTHER SWINGS ACROSS LATER SATURDAY. THESE WILL ENHANCE SNOW
SHOWERS OVER THE HIGHER MTNS AS WELL AS WINDS AROUND THE MTNS.
TEMPS WILL REMAIN ON THE COOL SIDE...BUT CLOSE TO SEASONAL
AVERAGES. ONE DIFFICULTY WILL STILL BE EFFECTS FROM GOOD SNOW
COVER OVER THE PANHANDLE...WHERE COLD AIR TRAPPING IN THE NORTH
PLATTE RIVER VALLEY KEPT TEMPS IN THE 20S TODAY. COULD BE SOME
FOG THERE AGAIN TONIGHT THOUGH A LIGHT DOWNSLOPE BREEZE WILL
HOPEFULLY LIMIT ITS THICKNESS SOME. WENT ON THE COOL SIDE FOR MAXS
THERE ON SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

SUNDAY...WINDY DAY PER PROGGED SURFACE THROUGH 700 MB GRADIENTS AND
DEEP UNIDIRECTIONAL NORTHWEST FLOW ALOFT. LONG DURATION HEAVY
SNOWFALL EVENT WILL CRANK UP OVER OUR SNOWY AND SIERRA MADRE
RANGES...AND TO A LESSER EXTENT OVER THE NORTHERN LARAMIE RANGE
BASED ON DECENT LOW AND MID LEVEL MOISTURE TRANSPORT WITH
OROGRAPHICS. WE WILL LIKELY BE ISSUING WINTER STORM WARNINGS FOR
LONG DURATION SNOWFALL EVENT OVER OUR SNOWY AND SIERRA MADRES...AND
POSSIBLY OVER THE NORTHERN LARAMIE RANGE.

MONDAY...COLD FRONT MOVES THROUGH IN STRONG NORTHWEST FLOW
ALOFT...WITH WINDY CONDITIONS PER PROGGED SURFACE THROUGH 700 MB
GRADIENTS...AND THE LONG DURATION OROGRAPHIC SNOWS WILL CONTINUE
ACROSS OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES.
ISOLATED TO SCATTERED SNOW SHOWERS ELSEWHERE IN COLD AIR ADVECTION
ALOFT.

TUESDAY...FLOW ALOFT TURNS MORE NORTHERLY WITH OROGRAPHIC SNOWS
DECREASING TO ONLY OVER THE MOUNTAINS...AND DRY ELSEWHERE DUE TO
LIMITED LOW AND MID LEVEL MOISTURE. DECENT TRAVEL PERIOD FOR
CHRISTMAS TRAVEL WITH RESPECT TO SNOWFALL ONLY OVER THE
MOUNTAINS...ALBEIT WITH TYPICALLY BRISK WINDS PRODUCING OUR TYPICAL
WINDY SEASON WINDS.

CHRISTMAS EVE DAY (WEDNESDAY)...CHANCES FOR A WHITE CHRISTMAS
EVE...AND CHRISTMAS...ARE LOOKING INCREASINGLY LIKELY...ESPECIALLY
WITH A PREFERENCE FOR THE ECMWF SOLUTION SHOWING NEXT DECENT
SHORTWAVE TROUGH ALOFT CARVING OUT OVER IDAHO WITH THE ASSOCIATED
BAND OF SNOWFALL EXTENDING ACROSS THE SOUTHERN HALF OF WYOMING BY
THE EVENING OF CHRISTMAS EVE. QPF SOLUTION ON THE GFS LOOKS TOO FAR
NORTH...AND ESPECIALLY WITH THE TYPICAL GFS DRY BIAS IN THE WINTER.

CHRISTMAS DAY...IF YOU LOVE SNOW ON CHRISTMAS DAY...YOU WILL LOVE
THE FACT THAT THE GFS AND ECMWF ARE STRIKINGLY SIMILAR IN DEPICTING
A WELL PRONOUNCED SHORTWAVE TROUGH ALOFT OVER SOUTHWEST WYOMING WITH
BOTH MODELS SHOWING A DECENT BAND OF LIGHT TO MODERATE SNOW
EXTENDING ACROSS SOUTHERN WYOMING AND NORTHERN COLORADO...WITH THE
ECMWF SLIGHTLY FURTHER NORTH WITH THE SNOW BAND OVER OUR
COUNTIES...THUS FEEL CONFIDENT ENOUGH WITH EXPERIENCE AND BOTH
MODELS CONGRUITY...TO BOOST OUR SNOWFALL POPS INTO THE 30 TO 70
PERCENT RANGE SOUTH OF A DOUGLAS TO KIMBALL LINE. IF ALL COMES
TOGETHER AS THE MODELS INDICATE...WE WILL SEE ACCUMULATING SNOW DUE
TO THE BAROCLINIC BAND...UPSLOPE AND CYCLONIC CURVATURE LIFTING
FEATURES...WITH SNOWFALL DECREASING IN AREAL COVERAGE CHRISTMAS
AFTERNOON

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 650 PM MST THU DEC 18 2014

PATCHY FOG ONCE AGAIN POSSIBLE ACROSS LOW LYING PORTIONS OF THE
NEBRASKA PANHANDLE TONIGHT. SOME PATCHY FOG AND LOW CLOUDS ALSO
POSSIBLE WEST OF THE LARAMIE RANGE IN SOUTHCENTRAL WYOMING. WINDS
WILL BE LIGHT TONIGHT AND BECOMING BREEZY FRIDAY AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 300 PM MST THU DEC 18 2014

NO CONCERNS SEEN THROUGH THE WEEKEND WITH MOSTLY NON-CRITICAL
CONDITIONS. WINDS WILL INCREASE OVER THE WEEKEND BUT OTHERWISE
COOL TEMPERATURES WILL PREVAIL WITH MTN SNOW SHOWERS AT TIMES.

&&

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

$$

UPDATE...SML
SHORT TERM...RE
LONG TERM...RUBIN
AVIATION...SML
FIRE WEATHER...RE




000
FXUS65 KCYS 190336
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
836 PM MST THU DEC 18 2014

.UPDATE...
ISSUED AT 836 PM MST THU DEC 18 2014

NO BIG CHANGES TO TONIGHTS FORECAST BUT DUE TO LIGHT WINDS AND
RADIATIONAL COOLING THERE IS SOME PATCHY FOG INTO THE WESTERN
NEBRASKA PANHANDLE. FOG IS NOT SHOWING UP ON WEB CAMS...ONLY BEING
PICKED UP AT THE BFF ASOS. MOST LIKELY THIS IS SHALLOW THIN FOG
WHICH WILL HAVE LITTLE IMPACT FOR THE TIME BEING. NOT OUT OF THE
QUESTION FOR LOCALIZED DENSE FOG LATER TONIGHT BUT GENERALLY NOT
EXPECTING MUCH IN THE WAY OF COVERAGE OR SIGNIFICANT REDUCTIONS IN
VISIBILITY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

FAIRLY QUIET WEATHER EXPECTED OVERALL THE NEXT COUPLE DAYS WITH
JUST SOME SNOW SHOWERS OVER THE HIGHER MTNS AT TIMES AS A COUPLE
WEAK SHORTWAVES PASS BY. ONE WILL SCOOT ACROSS EARLY FRIDAY WHILE
ANOTHER SWINGS ACROSS LATER SATURDAY. THESE WILL ENHANCE SNOW
SHOWERS OVER THE HIGHER MTNS AS WELL AS WINDS AROUND THE MTNS.
TEMPS WILL REMAIN ON THE COOL SIDE...BUT CLOSE TO SEASONAL
AVERAGES. ONE DIFFICULTY WILL STILL BE EFFECTS FROM GOOD SNOW
COVER OVER THE PANHANDLE...WHERE COLD AIR TRAPPING IN THE NORTH
PLATTE RIVER VALLEY KEPT TEMPS IN THE 20S TODAY. COULD BE SOME
FOG THERE AGAIN TONIGHT THOUGH A LIGHT DOWNSLOPE BREEZE WILL
HOPEFULLY LIMIT ITS THICKNESS SOME. WENT ON THE COOL SIDE FOR MAXS
THERE ON SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

SUNDAY...WINDY DAY PER PROGGED SURFACE THROUGH 700 MB GRADIENTS AND
DEEP UNIDIRECTIONAL NORTHWEST FLOW ALOFT. LONG DURATION HEAVY
SNOWFALL EVENT WILL CRANK UP OVER OUR SNOWY AND SIERRA MADRE
RANGES...AND TO A LESSER EXTENT OVER THE NORTHERN LARAMIE RANGE
BASED ON DECENT LOW AND MID LEVEL MOISTURE TRANSPORT WITH
OROGRAPHICS. WE WILL LIKELY BE ISSUING WINTER STORM WARNINGS FOR
LONG DURATION SNOWFALL EVENT OVER OUR SNOWY AND SIERRA MADRES...AND
POSSIBLY OVER THE NORTHERN LARAMIE RANGE.

MONDAY...COLD FRONT MOVES THROUGH IN STRONG NORTHWEST FLOW
ALOFT...WITH WINDY CONDITIONS PER PROGGED SURFACE THROUGH 700 MB
GRADIENTS...AND THE LONG DURATION OROGRAPHIC SNOWS WILL CONTINUE
ACROSS OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES.
ISOLATED TO SCATTERED SNOW SHOWERS ELSEWHERE IN COLD AIR ADVECTION
ALOFT.

TUESDAY...FLOW ALOFT TURNS MORE NORTHERLY WITH OROGRAPHIC SNOWS
DECREASING TO ONLY OVER THE MOUNTAINS...AND DRY ELSEWHERE DUE TO
LIMITED LOW AND MID LEVEL MOISTURE. DECENT TRAVEL PERIOD FOR
CHRISTMAS TRAVEL WITH RESPECT TO SNOWFALL ONLY OVER THE
MOUNTAINS...ALBEIT WITH TYPICALLY BRISK WINDS PRODUCING OUR TYPICAL
WINDY SEASON WINDS.

CHRISTMAS EVE DAY (WEDNESDAY)...CHANCES FOR A WHITE CHRISTMAS
EVE...AND CHRISTMAS...ARE LOOKING INCREASINGLY LIKELY...ESPECIALLY
WITH A PREFERENCE FOR THE ECMWF SOLUTION SHOWING NEXT DECENT
SHORTWAVE TROUGH ALOFT CARVING OUT OVER IDAHO WITH THE ASSOCIATED
BAND OF SNOWFALL EXTENDING ACROSS THE SOUTHERN HALF OF WYOMING BY
THE EVENING OF CHRISTMAS EVE. QPF SOLUTION ON THE GFS LOOKS TOO FAR
NORTH...AND ESPECIALLY WITH THE TYPICAL GFS DRY BIAS IN THE WINTER.

CHRISTMAS DAY...IF YOU LOVE SNOW ON CHRISTMAS DAY...YOU WILL LOVE
THE FACT THAT THE GFS AND ECMWF ARE STRIKINGLY SIMILAR IN DEPICTING
A WELL PRONOUNCED SHORTWAVE TROUGH ALOFT OVER SOUTHWEST WYOMING WITH
BOTH MODELS SHOWING A DECENT BAND OF LIGHT TO MODERATE SNOW
EXTENDING ACROSS SOUTHERN WYOMING AND NORTHERN COLORADO...WITH THE
ECMWF SLIGHTLY FURTHER NORTH WITH THE SNOW BAND OVER OUR
COUNTIES...THUS FEEL CONFIDENT ENOUGH WITH EXPERIENCE AND BOTH
MODELS CONGRUITY...TO BOOST OUR SNOWFALL POPS INTO THE 30 TO 70
PERCENT RANGE SOUTH OF A DOUGLAS TO KIMBALL LINE. IF ALL COMES
TOGETHER AS THE MODELS INDICATE...WE WILL SEE ACCUMULATING SNOW DUE
TO THE BAROCLINIC BAND...UPSLOPE AND CYCLONIC CURVATURE LIFTING
FEATURES...WITH SNOWFALL DECREASING IN AREAL COVERAGE CHRISTMAS
AFTERNOON

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 650 PM MST THU DEC 18 2014

PATCHY FOG ONCE AGAIN POSSIBLE ACROSS LOW LYING PORTIONS OF THE
NEBRASKA PANHANDLE TONIGHT. SOME PATCHY FOG AND LOW CLOUDS ALSO
POSSIBLE WEST OF THE LARAMIE RANGE IN SOUTHCENTRAL WYOMING. WINDS
WILL BE LIGHT TONIGHT AND BECOMING BREEZY FRIDAY AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 300 PM MST THU DEC 18 2014

NO CONCERNS SEEN THROUGH THE WEEKEND WITH MOSTLY NON-CRITICAL
CONDITIONS. WINDS WILL INCREASE OVER THE WEEKEND BUT OTHERWISE
COOL TEMPERATURES WILL PREVAIL WITH MTN SNOW SHOWERS AT TIMES.

&&

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

$$

UPDATE...SML
SHORT TERM...RE
LONG TERM...RUBIN
AVIATION...SML
FIRE WEATHER...RE




000
FXUS65 KCYS 190336
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
836 PM MST THU DEC 18 2014

.UPDATE...
ISSUED AT 836 PM MST THU DEC 18 2014

NO BIG CHANGES TO TONIGHTS FORECAST BUT DUE TO LIGHT WINDS AND
RADIATIONAL COOLING THERE IS SOME PATCHY FOG INTO THE WESTERN
NEBRASKA PANHANDLE. FOG IS NOT SHOWING UP ON WEB CAMS...ONLY BEING
PICKED UP AT THE BFF ASOS. MOST LIKELY THIS IS SHALLOW THIN FOG
WHICH WILL HAVE LITTLE IMPACT FOR THE TIME BEING. NOT OUT OF THE
QUESTION FOR LOCALIZED DENSE FOG LATER TONIGHT BUT GENERALLY NOT
EXPECTING MUCH IN THE WAY OF COVERAGE OR SIGNIFICANT REDUCTIONS IN
VISIBILITY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

FAIRLY QUIET WEATHER EXPECTED OVERALL THE NEXT COUPLE DAYS WITH
JUST SOME SNOW SHOWERS OVER THE HIGHER MTNS AT TIMES AS A COUPLE
WEAK SHORTWAVES PASS BY. ONE WILL SCOOT ACROSS EARLY FRIDAY WHILE
ANOTHER SWINGS ACROSS LATER SATURDAY. THESE WILL ENHANCE SNOW
SHOWERS OVER THE HIGHER MTNS AS WELL AS WINDS AROUND THE MTNS.
TEMPS WILL REMAIN ON THE COOL SIDE...BUT CLOSE TO SEASONAL
AVERAGES. ONE DIFFICULTY WILL STILL BE EFFECTS FROM GOOD SNOW
COVER OVER THE PANHANDLE...WHERE COLD AIR TRAPPING IN THE NORTH
PLATTE RIVER VALLEY KEPT TEMPS IN THE 20S TODAY. COULD BE SOME
FOG THERE AGAIN TONIGHT THOUGH A LIGHT DOWNSLOPE BREEZE WILL
HOPEFULLY LIMIT ITS THICKNESS SOME. WENT ON THE COOL SIDE FOR MAXS
THERE ON SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

SUNDAY...WINDY DAY PER PROGGED SURFACE THROUGH 700 MB GRADIENTS AND
DEEP UNIDIRECTIONAL NORTHWEST FLOW ALOFT. LONG DURATION HEAVY
SNOWFALL EVENT WILL CRANK UP OVER OUR SNOWY AND SIERRA MADRE
RANGES...AND TO A LESSER EXTENT OVER THE NORTHERN LARAMIE RANGE
BASED ON DECENT LOW AND MID LEVEL MOISTURE TRANSPORT WITH
OROGRAPHICS. WE WILL LIKELY BE ISSUING WINTER STORM WARNINGS FOR
LONG DURATION SNOWFALL EVENT OVER OUR SNOWY AND SIERRA MADRES...AND
POSSIBLY OVER THE NORTHERN LARAMIE RANGE.

MONDAY...COLD FRONT MOVES THROUGH IN STRONG NORTHWEST FLOW
ALOFT...WITH WINDY CONDITIONS PER PROGGED SURFACE THROUGH 700 MB
GRADIENTS...AND THE LONG DURATION OROGRAPHIC SNOWS WILL CONTINUE
ACROSS OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES.
ISOLATED TO SCATTERED SNOW SHOWERS ELSEWHERE IN COLD AIR ADVECTION
ALOFT.

TUESDAY...FLOW ALOFT TURNS MORE NORTHERLY WITH OROGRAPHIC SNOWS
DECREASING TO ONLY OVER THE MOUNTAINS...AND DRY ELSEWHERE DUE TO
LIMITED LOW AND MID LEVEL MOISTURE. DECENT TRAVEL PERIOD FOR
CHRISTMAS TRAVEL WITH RESPECT TO SNOWFALL ONLY OVER THE
MOUNTAINS...ALBEIT WITH TYPICALLY BRISK WINDS PRODUCING OUR TYPICAL
WINDY SEASON WINDS.

CHRISTMAS EVE DAY (WEDNESDAY)...CHANCES FOR A WHITE CHRISTMAS
EVE...AND CHRISTMAS...ARE LOOKING INCREASINGLY LIKELY...ESPECIALLY
WITH A PREFERENCE FOR THE ECMWF SOLUTION SHOWING NEXT DECENT
SHORTWAVE TROUGH ALOFT CARVING OUT OVER IDAHO WITH THE ASSOCIATED
BAND OF SNOWFALL EXTENDING ACROSS THE SOUTHERN HALF OF WYOMING BY
THE EVENING OF CHRISTMAS EVE. QPF SOLUTION ON THE GFS LOOKS TOO FAR
NORTH...AND ESPECIALLY WITH THE TYPICAL GFS DRY BIAS IN THE WINTER.

CHRISTMAS DAY...IF YOU LOVE SNOW ON CHRISTMAS DAY...YOU WILL LOVE
THE FACT THAT THE GFS AND ECMWF ARE STRIKINGLY SIMILAR IN DEPICTING
A WELL PRONOUNCED SHORTWAVE TROUGH ALOFT OVER SOUTHWEST WYOMING WITH
BOTH MODELS SHOWING A DECENT BAND OF LIGHT TO MODERATE SNOW
EXTENDING ACROSS SOUTHERN WYOMING AND NORTHERN COLORADO...WITH THE
ECMWF SLIGHTLY FURTHER NORTH WITH THE SNOW BAND OVER OUR
COUNTIES...THUS FEEL CONFIDENT ENOUGH WITH EXPERIENCE AND BOTH
MODELS CONGRUITY...TO BOOST OUR SNOWFALL POPS INTO THE 30 TO 70
PERCENT RANGE SOUTH OF A DOUGLAS TO KIMBALL LINE. IF ALL COMES
TOGETHER AS THE MODELS INDICATE...WE WILL SEE ACCUMULATING SNOW DUE
TO THE BAROCLINIC BAND...UPSLOPE AND CYCLONIC CURVATURE LIFTING
FEATURES...WITH SNOWFALL DECREASING IN AREAL COVERAGE CHRISTMAS
AFTERNOON

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 650 PM MST THU DEC 18 2014

PATCHY FOG ONCE AGAIN POSSIBLE ACROSS LOW LYING PORTIONS OF THE
NEBRASKA PANHANDLE TONIGHT. SOME PATCHY FOG AND LOW CLOUDS ALSO
POSSIBLE WEST OF THE LARAMIE RANGE IN SOUTHCENTRAL WYOMING. WINDS
WILL BE LIGHT TONIGHT AND BECOMING BREEZY FRIDAY AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 300 PM MST THU DEC 18 2014

NO CONCERNS SEEN THROUGH THE WEEKEND WITH MOSTLY NON-CRITICAL
CONDITIONS. WINDS WILL INCREASE OVER THE WEEKEND BUT OTHERWISE
COOL TEMPERATURES WILL PREVAIL WITH MTN SNOW SHOWERS AT TIMES.

&&

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

$$

UPDATE...SML
SHORT TERM...RE
LONG TERM...RUBIN
AVIATION...SML
FIRE WEATHER...RE





000
FXUS65 KCYS 190053
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
553 PM MST THU DEC 18 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

FAIRLY QUIET WEATHER EXPECTED OVERALL THE NEXT COUPLE DAYS WITH
JUST SOME SNOW SHOWERS OVER THE HIGHER MTNS AT TIMES AS A COUPLE
WEAK SHORTWAVES PASS BY. ONE WILL SCOOT ACROSS EARLY FRIDAY WHILE
ANOTHER SWINGS ACROSS LATER SATURDAY. THESE WILL ENHANCE SNOW
SHOWERS OVER THE HIGHER MTNS AS WELL AS WINDS AROUND THE MTNS.
TEMPS WILL REMAIN ON THE COOL SIDE...BUT CLOSE TO SEASONAL
AVERAGES. ONE DIFFICULTY WILL STILL BE EFFECTS FROM GOOD SNOW
COVER OVER THE PANHANDLE...WHERE COLD AIR TRAPPING IN THE NORTH
PLATTE RIVER VALLEY KEPT TEMPS IN THE 20S TODAY. COULD BE SOME
FOG THERE AGAIN TONIGHT THOUGH A LIGHT DOWNSLOPE BREEZE WILL
HOPEFULLY LIMIT ITS THICKNESS SOME. WENT ON THE COOL SIDE FOR MAXS
THERE ON SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

SUNDAY...WINDY DAY PER PROGGED SURFACE THROUGH 700 MB GRADIENTS AND
DEEP UNIDIRECTIONAL NORTHWEST FLOW ALOFT. LONG DURATION HEAVY
SNOWFALL EVENT WILL CRANK UP OVER OUR SNOWY AND SIERRA MADRE
RANGES...AND TO A LESSER EXTENT OVER THE NORTHERN LARAMIE RANGE
BASED ON DECENT LOW AND MID LEVEL MOISTURE TRANSPORT WITH
OROGRAPHICS. WE WILL LIKELY BE ISSUING WINTER STORM WARNINGS FOR
LONG DURATION SNOWFALL EVENT OVER OUR SNOWY AND SIERRA MADRES...AND
POSSIBLY OVER THE NORTHERN LARAMIE RANGE.

MONDAY...COLD FRONT MOVES THROUGH IN STRONG NORTHWEST FLOW
ALOFT...WITH WINDY CONDITIONS PER PROGGED SURFACE THROUGH 700 MB
GRADIENTS...AND THE LONG DURATION OROGRAPHIC SNOWS WILL CONTINUE
ACROSS OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES.
ISOLATED TO SCATTERED SNOW SHOWERS ELSEWHERE IN COLD AIR ADVECTION
ALOFT.

TUESDAY...FLOW ALOFT TURNS MORE NORTHERLY WITH OROGRAPHIC SNOWS
DECREASING TO ONLY OVER THE MOUNTAINS...AND DRY ELSEWHERE DUE TO
LIMITED LOW AND MID LEVEL MOISTURE. DECENT TRAVEL PERIOD FOR
CHRISTMAS TRAVEL WITH RESPECT TO SNOWFALL ONLY OVER THE
MOUNTAINS...ALBEIT WITH TYPICALLY BRISK WINDS PRODUCING OUR TYPICAL
WINDY SEASON WINDS.

CHRISTMAS EVE DAY (WEDNESDAY)...CHANCES FOR A WHITE CHRISTMAS
EVE...AND CHRISTMAS...ARE LOOKING INCREASINGLY LIKELY...ESPECIALLY
WITH A PREFERENCE FOR THE ECMWF SOLUTION SHOWING NEXT DECENT
SHORTWAVE TROUGH ALOFT CARVING OUT OVER IDAHO WITH THE ASSOCIATED
BAND OF SNOWFALL EXTENDING ACROSS THE SOUTHERN HALF OF WYOMING BY
THE EVENING OF CHRISTMAS EVE. QPF SOLUTION ON THE GFS LOOKS TOO FAR
NORTH...AND ESPECIALLY WITH THE TYPICAL GFS DRY BIAS IN THE WINTER.

CHRISTMAS DAY...IF YOU LOVE SNOW ON CHRISTMAS DAY...YOU WILL LOVE
THE FACT THAT THE GFS AND ECMWF ARE STRIKINGLY SIMILAR IN DEPICTING
A WELL PRONOUNCED SHORTWAVE TROUGH ALOFT OVER SOUTHWEST WYOMING WITH
BOTH MODELS SHOWING A DECENT BAND OF LIGHT TO MODERATE SNOW
EXTENDING ACROSS SOUTHERN WYOMING AND NORTHERN COLORADO...WITH THE
ECMWF SLIGHTLY FURTHER NORTH WITH THE SNOW BAND OVER OUR
COUNTIES...THUS FEEL CONFIDENT ENOUGH WITH EXPERIENCE AND BOTH
MODELS CONGRUITY...TO BOOST OUR SNOWFALL POPS INTO THE 30 TO 70
PERCENT RANGE SOUTH OF A DOUGLAS TO KIMBALL LINE. IF ALL COMES
TOGETHER AS THE MODELS INDICATE...WE WILL SEE ACCUMULATING SNOW DUE
TO THE BAROCLINIC BAND...UPSLOPE AND CYCLONIC CURVATURE LIFTING
FEATURES...WITH SNOWFALL DECREASING IN AREAL COVERAGE CHRISTMAS
AFTERNOON

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 650 PM MST THU DEC 18 2014

PATCHY FOG ONCE AGAIN POSSIBLE ACROSS LOW LYING PORTIONS OF THE
NEBRASKA PANHANDLE TONIGHT. SOME PATCHY FOG AND LOW CLOUDS ALSO
POSSIBLE WEST OF THE LARAMIE RANGE IN SOUTHCENTRAL WYOMING. WINDS
WILL BE LIGHT TONIGHT AND BECOMING BREEZY FRIDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MST THU DEC 18 2014

NO CONCERNS SEEN THROUGH THE WEEKEND WITH MOSTLY NON-CRITICAL
CONDITIONS. WINDS WILL INCREASE OVER THE WEEKEND BUT OTHERWISE
COOL TEMPERATURES WILL PREVAIL WITH MTN SNOW SHOWERS AT TIMES.

&&

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

&&

$$

SHORT TERM...RE
LONG TERM...RUBIN
AVIATION...SML
FIRE WEATHER...RE




000
FXUS65 KCYS 190053
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
553 PM MST THU DEC 18 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

FAIRLY QUIET WEATHER EXPECTED OVERALL THE NEXT COUPLE DAYS WITH
JUST SOME SNOW SHOWERS OVER THE HIGHER MTNS AT TIMES AS A COUPLE
WEAK SHORTWAVES PASS BY. ONE WILL SCOOT ACROSS EARLY FRIDAY WHILE
ANOTHER SWINGS ACROSS LATER SATURDAY. THESE WILL ENHANCE SNOW
SHOWERS OVER THE HIGHER MTNS AS WELL AS WINDS AROUND THE MTNS.
TEMPS WILL REMAIN ON THE COOL SIDE...BUT CLOSE TO SEASONAL
AVERAGES. ONE DIFFICULTY WILL STILL BE EFFECTS FROM GOOD SNOW
COVER OVER THE PANHANDLE...WHERE COLD AIR TRAPPING IN THE NORTH
PLATTE RIVER VALLEY KEPT TEMPS IN THE 20S TODAY. COULD BE SOME
FOG THERE AGAIN TONIGHT THOUGH A LIGHT DOWNSLOPE BREEZE WILL
HOPEFULLY LIMIT ITS THICKNESS SOME. WENT ON THE COOL SIDE FOR MAXS
THERE ON SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

SUNDAY...WINDY DAY PER PROGGED SURFACE THROUGH 700 MB GRADIENTS AND
DEEP UNIDIRECTIONAL NORTHWEST FLOW ALOFT. LONG DURATION HEAVY
SNOWFALL EVENT WILL CRANK UP OVER OUR SNOWY AND SIERRA MADRE
RANGES...AND TO A LESSER EXTENT OVER THE NORTHERN LARAMIE RANGE
BASED ON DECENT LOW AND MID LEVEL MOISTURE TRANSPORT WITH
OROGRAPHICS. WE WILL LIKELY BE ISSUING WINTER STORM WARNINGS FOR
LONG DURATION SNOWFALL EVENT OVER OUR SNOWY AND SIERRA MADRES...AND
POSSIBLY OVER THE NORTHERN LARAMIE RANGE.

MONDAY...COLD FRONT MOVES THROUGH IN STRONG NORTHWEST FLOW
ALOFT...WITH WINDY CONDITIONS PER PROGGED SURFACE THROUGH 700 MB
GRADIENTS...AND THE LONG DURATION OROGRAPHIC SNOWS WILL CONTINUE
ACROSS OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES.
ISOLATED TO SCATTERED SNOW SHOWERS ELSEWHERE IN COLD AIR ADVECTION
ALOFT.

TUESDAY...FLOW ALOFT TURNS MORE NORTHERLY WITH OROGRAPHIC SNOWS
DECREASING TO ONLY OVER THE MOUNTAINS...AND DRY ELSEWHERE DUE TO
LIMITED LOW AND MID LEVEL MOISTURE. DECENT TRAVEL PERIOD FOR
CHRISTMAS TRAVEL WITH RESPECT TO SNOWFALL ONLY OVER THE
MOUNTAINS...ALBEIT WITH TYPICALLY BRISK WINDS PRODUCING OUR TYPICAL
WINDY SEASON WINDS.

CHRISTMAS EVE DAY (WEDNESDAY)...CHANCES FOR A WHITE CHRISTMAS
EVE...AND CHRISTMAS...ARE LOOKING INCREASINGLY LIKELY...ESPECIALLY
WITH A PREFERENCE FOR THE ECMWF SOLUTION SHOWING NEXT DECENT
SHORTWAVE TROUGH ALOFT CARVING OUT OVER IDAHO WITH THE ASSOCIATED
BAND OF SNOWFALL EXTENDING ACROSS THE SOUTHERN HALF OF WYOMING BY
THE EVENING OF CHRISTMAS EVE. QPF SOLUTION ON THE GFS LOOKS TOO FAR
NORTH...AND ESPECIALLY WITH THE TYPICAL GFS DRY BIAS IN THE WINTER.

CHRISTMAS DAY...IF YOU LOVE SNOW ON CHRISTMAS DAY...YOU WILL LOVE
THE FACT THAT THE GFS AND ECMWF ARE STRIKINGLY SIMILAR IN DEPICTING
A WELL PRONOUNCED SHORTWAVE TROUGH ALOFT OVER SOUTHWEST WYOMING WITH
BOTH MODELS SHOWING A DECENT BAND OF LIGHT TO MODERATE SNOW
EXTENDING ACROSS SOUTHERN WYOMING AND NORTHERN COLORADO...WITH THE
ECMWF SLIGHTLY FURTHER NORTH WITH THE SNOW BAND OVER OUR
COUNTIES...THUS FEEL CONFIDENT ENOUGH WITH EXPERIENCE AND BOTH
MODELS CONGRUITY...TO BOOST OUR SNOWFALL POPS INTO THE 30 TO 70
PERCENT RANGE SOUTH OF A DOUGLAS TO KIMBALL LINE. IF ALL COMES
TOGETHER AS THE MODELS INDICATE...WE WILL SEE ACCUMULATING SNOW DUE
TO THE BAROCLINIC BAND...UPSLOPE AND CYCLONIC CURVATURE LIFTING
FEATURES...WITH SNOWFALL DECREASING IN AREAL COVERAGE CHRISTMAS
AFTERNOON

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 650 PM MST THU DEC 18 2014

PATCHY FOG ONCE AGAIN POSSIBLE ACROSS LOW LYING PORTIONS OF THE
NEBRASKA PANHANDLE TONIGHT. SOME PATCHY FOG AND LOW CLOUDS ALSO
POSSIBLE WEST OF THE LARAMIE RANGE IN SOUTHCENTRAL WYOMING. WINDS
WILL BE LIGHT TONIGHT AND BECOMING BREEZY FRIDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MST THU DEC 18 2014

NO CONCERNS SEEN THROUGH THE WEEKEND WITH MOSTLY NON-CRITICAL
CONDITIONS. WINDS WILL INCREASE OVER THE WEEKEND BUT OTHERWISE
COOL TEMPERATURES WILL PREVAIL WITH MTN SNOW SHOWERS AT TIMES.

&&

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

&&

$$

SHORT TERM...RE
LONG TERM...RUBIN
AVIATION...SML
FIRE WEATHER...RE





000
FXUS65 KCYS 182207
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
308 PM MST THU DEC 18 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

FAIRLY QUIET WEATHER EXPECTED OVERALL THE NEXT COUPLE DAYS WITH
JUST SOME SNOW SHOWERS OVER THE HIGHER MTNS AT TIMES AS A COUPLE
WEAK SHORTWAVES PASS BY. ONE WILL SCOOT ACROSS EARLY FRIDAY WHILE
ANOTHER SWINGS ACROSS LATER SATURDAY. THESE WILL ENHANCE SNOW
SHOWERS OVER THE HIGHER MTNS AS WELL AS WINDS AROUND THE MTNS.
TEMPS WILL REMAIN ON THE COOL SIDE...BUT CLOSE TO SEASONAL
AVERAGES. ONE DIFFICULTY WILL STILL BE EFFECTS FROM GOOD SNOW
COVER OVER THE PANHANDLE...WHERE COLD AIR TRAPPING IN THE NORTH
PLATTE RIVER VALLEY KEPT TEMPS IN THE 20S TODAY. COULD BE SOME
FOG THERE AGAIN TONIGHT THOUGH A LIGHT DOWNSLOPE BREEZE WILL
HOPEFULLY LIMIT ITS THICKNESS SOME. WENT ON THE COOL SIDE FOR MAXS
THERE ON SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

SUNDAY...WINDY DAY PER PROGGED SURFACE THROUGH 700 MB GRADIENTS AND
DEEP UNIDIRECTIONAL NORTHWEST FLOW ALOFT. LONG DURATION HEAVY
SNOWFALL EVENT WILL CRANK UP OVER OUR SNOWY AND SIERRA MADRE
RANGES...AND TO A LESSER EXTENT OVER THE NORTHERN LARAMIE RANGE
BASED ON DECENT LOW AND MID LEVEL MOISTURE TRANSPORT WITH
OROGRAPHICS. WE WILL LIKELY BE ISSUING WINTER STORM WARNINGS FOR
LONG DURATION SNOWFALL EVENT OVER OUR SNOWY AND SIERRA MADRES...AND
POSSIBLY OVER THE NORTHERN LARAMIE RANGE.

MONDAY...COLD FRONT MOVES THROUGH IN STRONG NORTHWEST FLOW
ALOFT...WITH WINDY CONDITIONS PER PROGGED SURFACE THROUGH 700 MB
GRADIENTS...AND THE LONG DURATION OROGRAPHIC SNOWS WILL CONTINUE
ACROSS OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES.
ISOLATED TO SCATTERED SNOW SHOWERS ELSEWHERE IN COLD AIR ADVECTION
ALOFT.

TUESDAY...FLOW ALOFT TURNS MORE NORTHERLY WITH OROGRAPHIC SNOWS
DECREASING TO ONLY OVER THE MOUNTAINS...AND DRY ELSEWHERE DUE TO
LIMITED LOW AND MID LEVEL MOISTURE. DECENT TRAVEL PERIOD FOR
CHRISTMAS TRAVEL WITH RESPECT TO SNOWFALL ONLY OVER THE
MOUNTAINS...ALBEIT WITH TYPICALLY BRISK WINDS PRODUCING OUR TYPICAL
WINDY SEASON WINDS.

CHRISTMAS EVE DAY (WEDNESDAY)...CHANCES FOR A WHITE CHRISTMAS
EVE...AND CHRISTMAS...ARE LOOKING INCREASINGLY LIKELY...ESPECIALLY
WITH A PREFERENCE FOR THE ECMWF SOLUTION SHOWING NEXT DECENT
SHORTWAVE TROUGH ALOFT CARVING OUT OVER IDAHO WITH THE ASSOCIATED
BAND OF SNOWFALL EXTENDING ACROSS THE SOUTHERN HALF OF WYOMING BY
THE EVENING OF CHRISTMAS EVE. QPF SOLUTION ON THE GFS LOOKS TOO FAR
NORTH...AND ESPECIALLY WITH THE TYPICAL GFS DRY BIAS IN THE WINTER.

CHRISTMAS DAY...IF YOU LOVE SNOW ON CHRISTMAS DAY...YOU WILL LOVE
THE FACT THAT THE GFS AND ECMWF ARE STRIKINGLY SIMILAR IN DEPICTING
A WELL PRONOUNCED SHORTWAVE TROUGH ALOFT OVER SOUTHWEST WYOMING WITH
BOTH MODELS SHOWING A DECENT BAND OF LIGHT TO MODERATE SNOW
EXTENDING ACROSS SOUTHERN WYOMING AND NORTHERN COLORADO...WITH THE
ECMWF SLIGHTLY FURTHER NORTH WITH THE SNOW BAND OVER OUR
COUNTIES...THUS FEEL CONFIDENT ENOUGH WITH EXPERIENCE AND BOTH
MODELS CONGRUITY...TO BOOST OUR SNOWFALL POPS INTO THE 30 TO 70
PERCENT RANGE SOUTH OF A DOUGLAS TO KIMBALL LINE. IF ALL COMES
TOGETHER AS THE MODELS INDICATE...WE WILL SEE ACCUMULATING SNOW DUE
TO THE BAROCLINIC BAND...UPSLOPE AND CYCLONIC CURVATURE LIFTING
FEATURES...WITH SNOWFALL DECREASING IN AREAL COVERAGE CHRISTMAS
AFTERNOON.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1045 AM MST THU DEC 18 2014

VFR EXPECTED OVERALL THROUGH THE PERIOD WITH LIGHT WINDS. SOME
FOG MAY REDEVELOP IN THE NORTH PLATTE RIVER VALLEY TONIGHT BUT A
MORE DOWNSLOPE BREEZE SHOULD LIMIT ITS EXTENT OR DENSITY.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MST THU DEC 18 2014

NO CONCERNS SEEN THROUGH THE WEEKEND WITH MOSTLY NON-CRITICAL
CONDITIONS. WINDS WILL INCREASE OVER THE WEEKEND BUT OTHERWISE
COOL TEMPERATURES WILL PREVAIL WITH MTN SNOW SHOWERS AT TIMES.

&&

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

$$

SHORT TERM...RE
LONG TERM...RUBIN
AVIATION...RE
FIRE WEATHER...RE




000
FXUS65 KCYS 182207
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
308 PM MST THU DEC 18 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

FAIRLY QUIET WEATHER EXPECTED OVERALL THE NEXT COUPLE DAYS WITH
JUST SOME SNOW SHOWERS OVER THE HIGHER MTNS AT TIMES AS A COUPLE
WEAK SHORTWAVES PASS BY. ONE WILL SCOOT ACROSS EARLY FRIDAY WHILE
ANOTHER SWINGS ACROSS LATER SATURDAY. THESE WILL ENHANCE SNOW
SHOWERS OVER THE HIGHER MTNS AS WELL AS WINDS AROUND THE MTNS.
TEMPS WILL REMAIN ON THE COOL SIDE...BUT CLOSE TO SEASONAL
AVERAGES. ONE DIFFICULTY WILL STILL BE EFFECTS FROM GOOD SNOW
COVER OVER THE PANHANDLE...WHERE COLD AIR TRAPPING IN THE NORTH
PLATTE RIVER VALLEY KEPT TEMPS IN THE 20S TODAY. COULD BE SOME
FOG THERE AGAIN TONIGHT THOUGH A LIGHT DOWNSLOPE BREEZE WILL
HOPEFULLY LIMIT ITS THICKNESS SOME. WENT ON THE COOL SIDE FOR MAXS
THERE ON SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 PM MST THU DEC 18 2014

SUNDAY...WINDY DAY PER PROGGED SURFACE THROUGH 700 MB GRADIENTS AND
DEEP UNIDIRECTIONAL NORTHWEST FLOW ALOFT. LONG DURATION HEAVY
SNOWFALL EVENT WILL CRANK UP OVER OUR SNOWY AND SIERRA MADRE
RANGES...AND TO A LESSER EXTENT OVER THE NORTHERN LARAMIE RANGE
BASED ON DECENT LOW AND MID LEVEL MOISTURE TRANSPORT WITH
OROGRAPHICS. WE WILL LIKELY BE ISSUING WINTER STORM WARNINGS FOR
LONG DURATION SNOWFALL EVENT OVER OUR SNOWY AND SIERRA MADRES...AND
POSSIBLY OVER THE NORTHERN LARAMIE RANGE.

MONDAY...COLD FRONT MOVES THROUGH IN STRONG NORTHWEST FLOW
ALOFT...WITH WINDY CONDITIONS PER PROGGED SURFACE THROUGH 700 MB
GRADIENTS...AND THE LONG DURATION OROGRAPHIC SNOWS WILL CONTINUE
ACROSS OUR NORTHERN LARAMIE...SNOWY AND SIERRA MADRE RANGES.
ISOLATED TO SCATTERED SNOW SHOWERS ELSEWHERE IN COLD AIR ADVECTION
ALOFT.

TUESDAY...FLOW ALOFT TURNS MORE NORTHERLY WITH OROGRAPHIC SNOWS
DECREASING TO ONLY OVER THE MOUNTAINS...AND DRY ELSEWHERE DUE TO
LIMITED LOW AND MID LEVEL MOISTURE. DECENT TRAVEL PERIOD FOR
CHRISTMAS TRAVEL WITH RESPECT TO SNOWFALL ONLY OVER THE
MOUNTAINS...ALBEIT WITH TYPICALLY BRISK WINDS PRODUCING OUR TYPICAL
WINDY SEASON WINDS.

CHRISTMAS EVE DAY (WEDNESDAY)...CHANCES FOR A WHITE CHRISTMAS
EVE...AND CHRISTMAS...ARE LOOKING INCREASINGLY LIKELY...ESPECIALLY
WITH A PREFERENCE FOR THE ECMWF SOLUTION SHOWING NEXT DECENT
SHORTWAVE TROUGH ALOFT CARVING OUT OVER IDAHO WITH THE ASSOCIATED
BAND OF SNOWFALL EXTENDING ACROSS THE SOUTHERN HALF OF WYOMING BY
THE EVENING OF CHRISTMAS EVE. QPF SOLUTION ON THE GFS LOOKS TOO FAR
NORTH...AND ESPECIALLY WITH THE TYPICAL GFS DRY BIAS IN THE WINTER.

CHRISTMAS DAY...IF YOU LOVE SNOW ON CHRISTMAS DAY...YOU WILL LOVE
THE FACT THAT THE GFS AND ECMWF ARE STRIKINGLY SIMILAR IN DEPICTING
A WELL PRONOUNCED SHORTWAVE TROUGH ALOFT OVER SOUTHWEST WYOMING WITH
BOTH MODELS SHOWING A DECENT BAND OF LIGHT TO MODERATE SNOW
EXTENDING ACROSS SOUTHERN WYOMING AND NORTHERN COLORADO...WITH THE
ECMWF SLIGHTLY FURTHER NORTH WITH THE SNOW BAND OVER OUR
COUNTIES...THUS FEEL CONFIDENT ENOUGH WITH EXPERIENCE AND BOTH
MODELS CONGRUITY...TO BOOST OUR SNOWFALL POPS INTO THE 30 TO 70
PERCENT RANGE SOUTH OF A DOUGLAS TO KIMBALL LINE. IF ALL COMES
TOGETHER AS THE MODELS INDICATE...WE WILL SEE ACCUMULATING SNOW DUE
TO THE BAROCLINIC BAND...UPSLOPE AND CYCLONIC CURVATURE LIFTING
FEATURES...WITH SNOWFALL DECREASING IN AREAL COVERAGE CHRISTMAS
AFTERNOON.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1045 AM MST THU DEC 18 2014

VFR EXPECTED OVERALL THROUGH THE PERIOD WITH LIGHT WINDS. SOME
FOG MAY REDEVELOP IN THE NORTH PLATTE RIVER VALLEY TONIGHT BUT A
MORE DOWNSLOPE BREEZE SHOULD LIMIT ITS EXTENT OR DENSITY.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MST THU DEC 18 2014

NO CONCERNS SEEN THROUGH THE WEEKEND WITH MOSTLY NON-CRITICAL
CONDITIONS. WINDS WILL INCREASE OVER THE WEEKEND BUT OTHERWISE
COOL TEMPERATURES WILL PREVAIL WITH MTN SNOW SHOWERS AT TIMES.

&&

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

$$

SHORT TERM...RE
LONG TERM...RUBIN
AVIATION...RE
FIRE WEATHER...RE





000
FXUS65 KCYS 181745
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1045 AM MST THU DEC 18 2014

.UPDATE...
ISSUED AT 1045 AM MST THU DEC 18 2014

MINOR UPDATE TO ADJUST FCST FOR CURRENT CONDITIONS.  LOWERED MAXS IN
THE NORTH PLATTE RIVER VALLEY AS COLD AIR TRAPPING SEEMS TO BE
OCCURRING THERE.  ADJUSTED CLOUD COVER OTHERWISE.

.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 319 AM MST THU DEC 18 2014

THE ONGOING LOCALLY DENSE FOG ALONG THE NORTH PLATTE RIVER VALLEY
WILL CARRY THE GREATEST IMPACT THRU THE PERIOD. LIGHT WINDS AND
MINIMAL DISRUPTIVE MID-LEVEL CLOUDS HAS YIELDED EFFICIENT
RADIATIONAL COOLING OVERNIGHT. VISIBILITIES HAVE BOUNCED BETWEEN
1/4SM AND 1/2SM FROM TORRINGTON TO SCOTTSBLUFF TO ALLIANCE DURING
THE OVERNIGHT HOURS. LATEST SATELLITE FOG PRODUCT DOES SHOW THE
LOW CLOUDS/FOG BEGINNING TO SHIFT EAST OUT OF THE ERN CWA...BUT
KEEPS IT IN THE NORTH PLATTE RIVER VALLEY. WILL LIKELY BE ABLE TO
CANCEL BOX BUTTE FROM THE DENSE FOG ADVISORY HERE SHORTLY...BUT
WILL LEAVE THE REST GOING FOR NOW. WEST WINDS WILL FINALLY KICK IN
THIS MORNING AS EASILY DISCERNIBLE SHORTWAVE SPINS OUT OF ERN
MONTANA INTO THE WRN DAKOTAS. THIS WILL EFFECTIVELY SCOUR OUT
MORNING VALLEY FOG. SHOULD ALSO SEE THE WIND PRONE AREAS BECOME
BREEZY. OTHERWISE WEAK WESTERLY FLOW WILL WORK INTO THE AREA TODAY
WILL KEEP DRY CONDITIONS OUTSIDE OF PERHAPS SOME VERY LIGHT
MOUNTAIN SNOW SHOWERS. ALTHOUGH SOME PATCHY FOG WILL BE A
POSSIBILITY AGAIN ALONG THE NORTH PLATTE RIVER VALLEY...DO NOT
ANTICIPATE IT TO BE THE EXTENT OF WHAT IT WAS TONIGHT. DID ADD
PATCHY MENTION ALONG THE NORTH PLATTE HOWEVER.

SUBSIDENCE ASSOCIATED WITH SHORTWAVE RIDGE AXIS WILL BUILD IN FOR
FRIDAY. THIS WILL YIELD A DRY...PARTLY SUNNY DAY. ANOTHER QUICK
MOVING...BUT DRY SHORTWAVE WILL CLIP EAST CENTRAL WYOMING AND THE
NRN NEBRASKA PANHANDLE FOR SATURDAY.

TEMPERATURES WILL REMAIN SEASONAL FOR BOTH TODAY AND TOMORROW WITH
HIGHS REACHING NR 30 WEST OF THE LARAMIE RANGE AND NR 40 OUT ON THE
ERN PLAINS. THE GRADIENT WILL LIKELY TICK UP AGAIN ON SATURDAY...SO
PRODUCING LOCALLY BREEZY CONDITIONS OVR THE WIND PRONE AREAS AND LEE-
SIDE ADIABATIC WARMING WHICH WILL BOOST TEMPS A FEW DEGREES OUT ON
THE ERN PLAINS.

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 319 AM MST THU DEC 18 2014

PRETTY ACTIVE EXTENDED PERIOD WITH WINDS ACROSS SOUTHEAST WY AND
MOUNTAIN SNOWS BEING THE PRIMARY CONCERNS. A STRONG UPPER LEVEL
JET WILL STRETCH FROM THE PACIFIC NORTHWEST INTO WY ON SUNDAY. AN
INCREASING LLVL GRADIENT WILL LIKELY RESULT IN HIGH WINDS AT LEAST
ACROSS THE WIND PRONE AREAS ON SUNDAY INTO SUNDAY NIGHT. THE GFS
SHOWS THE 850MB CAG-CPR GRADIENT RISING ABOVE 60 METERS BY 12Z SUN
AND MAXING OUT AT 85 METERS BY 12Z MON. THE MODELS HAVE BEEN
CONSISTENT WITH THIS OVER THE PAST FEW DAYS...SO OUR STRETCH OF
RELATIVELY WEAK WINDS OVER SOUTHEAST WY WILL BE COMING TO AN END.
FRONT WILL PUSH ACROSS THE AREA ON MON MORNING WITH THE SFC
PRESSURE GRADIENT BEGINNING TO RELAX. HOWEVER...WITH GOOD MIXING
AND LLVL LAPSE RATES IN THE POSTFRONTAL AIRMASS...WINDY CONDITIONS
WILL SPREAD ONTO THE PLAINS.

SEVERAL THINGS ARE ALSO COMING TOGETHER FOR A GOOD SNOW EVENT
ACROSS THE SIERRA MADRE AND SNOWY RANGES FROM SUNDAY INTO MONDAY.
THE REGION WILL BE IN THE LEFT EXIT REGION OF THE UPPER JET WITH
EXCELLENT 700-500MB MOISTURE STREAMING INTO WY FROM THE PACIFIC.
STRONG NORTHWESTERLY FLOW WILL PROVIDE GOOD OROGRAPHIC LIFT.
THE COARSE AND LIKELY UNDERDONE GFS SHOWS 1.25-1.75 INCHES OF SWE
FROM 12Z SUN THROUGH 12Z TUES. WOULD NOT BE SURPRISED TO SEE A FEW
LOCATIONS IN THE SIERRA MADRE RANGE PICK UP A FEW FEET OF SNOW IN
THIS TYPE OF PATTERN. OUTSIDE OF THE MTNS IT APPEARS THERE COULD
BE A BRIEF SHOT OF SNOW RIGHT BEHIND THE FRONT ON MON AFTN. IT
WILL DEFINITELY BE A CHILLY DAY ON MON DUE TO THE COMBINATION OF
COLDER TEMPS AND WIND. SNOW WILL DECREASE IN INTENSITY ON
TUES...THOUGH LIKELY NOT END COMPLETELY AS MOIST OROGRAPHICS
CONTINUE. ATTENTION THEN TURNS TO THE SYSTEM THAT WILL IMPACT THE
REGION IN THE WED NIGHT AND THURS TIMEFRAME. THE GFS IS MORE
PROGRESSIVE WITH THE SYSTEM COMPARED TO THE ECMWF WHICH AMPLIFIES
THE UPPER TROUGH ACROSS THE SOUTHWESTERN UNITED STATES. THIS IS
STILL OVER A WEEK AWAY...SO WILL NOT DISCUSS TOO MUCH AT THIS
TIME...HOWEVER THIS SYSTEM COULD DEFINITELY HAVE ADVERSE IMPACTS
AROUND CHRISTMAS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1045 AM MST THU DEC 18 2014

VFR EXPECTED OVERALL THROUGH THE PERIOD WITH LIGHT WINDS.  SOME FOG
MAY REDEVELOP IN THE NORTH PLATTE RIVER VALLEY TONIGHT BUT A MORE
DOWNSLOPE BREEZE SHOULD LIMIT ITS EXTENT OR DENSITY.

&&

.FIRE WEATHER...
ISSUED AT 319 AM MST THU DEC 18 2014

SEASONAL TEMPERATURES AND DRY CONDITIONS WILL
CONTINUE THROUGH THE UPCOMING WEEKEND LIMITING ANY FIRE WEATHER
CONCERNS. THE MOUNTAINS WILL SEE PERIODIC LIGHT SNOW BUT
ACCUMULATIONS WILL BE RELATIVELY LIGHT. HIGH TEMPERATURES WILL RISE
INTO THE 40S OVR THE ERN PLAINS FOR SUNDAY...BUT WITH SUFFICIENT
MOISTURE IN PLACE MINIMUM RELATIVE HUMIDITIES WILL ONLY FALL INTO
THE 40-50S. THE WINDY PATTERN WILL RETURN TO THE DISTRICT FOR SUNDAY
THROUGH TUESDAY WITH SEVERAL MORE FEET OF SNOW EXPECTED OVER THE
SNOWY AND SIERRA MADRE RANGES.

&&

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

&&

$$

UPDATE...RE
SHORT TERM...CAH
LONG TERM...ZF
AVIATION...RE
FIRE WEATHER...CAH




000
FXUS65 KCYS 181745
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1045 AM MST THU DEC 18 2014

.UPDATE...
ISSUED AT 1045 AM MST THU DEC 18 2014

MINOR UPDATE TO ADJUST FCST FOR CURRENT CONDITIONS.  LOWERED MAXS IN
THE NORTH PLATTE RIVER VALLEY AS COLD AIR TRAPPING SEEMS TO BE
OCCURRING THERE.  ADJUSTED CLOUD COVER OTHERWISE.

.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 319 AM MST THU DEC 18 2014

THE ONGOING LOCALLY DENSE FOG ALONG THE NORTH PLATTE RIVER VALLEY
WILL CARRY THE GREATEST IMPACT THRU THE PERIOD. LIGHT WINDS AND
MINIMAL DISRUPTIVE MID-LEVEL CLOUDS HAS YIELDED EFFICIENT
RADIATIONAL COOLING OVERNIGHT. VISIBILITIES HAVE BOUNCED BETWEEN
1/4SM AND 1/2SM FROM TORRINGTON TO SCOTTSBLUFF TO ALLIANCE DURING
THE OVERNIGHT HOURS. LATEST SATELLITE FOG PRODUCT DOES SHOW THE
LOW CLOUDS/FOG BEGINNING TO SHIFT EAST OUT OF THE ERN CWA...BUT
KEEPS IT IN THE NORTH PLATTE RIVER VALLEY. WILL LIKELY BE ABLE TO
CANCEL BOX BUTTE FROM THE DENSE FOG ADVISORY HERE SHORTLY...BUT
WILL LEAVE THE REST GOING FOR NOW. WEST WINDS WILL FINALLY KICK IN
THIS MORNING AS EASILY DISCERNIBLE SHORTWAVE SPINS OUT OF ERN
MONTANA INTO THE WRN DAKOTAS. THIS WILL EFFECTIVELY SCOUR OUT
MORNING VALLEY FOG. SHOULD ALSO SEE THE WIND PRONE AREAS BECOME
BREEZY. OTHERWISE WEAK WESTERLY FLOW WILL WORK INTO THE AREA TODAY
WILL KEEP DRY CONDITIONS OUTSIDE OF PERHAPS SOME VERY LIGHT
MOUNTAIN SNOW SHOWERS. ALTHOUGH SOME PATCHY FOG WILL BE A
POSSIBILITY AGAIN ALONG THE NORTH PLATTE RIVER VALLEY...DO NOT
ANTICIPATE IT TO BE THE EXTENT OF WHAT IT WAS TONIGHT. DID ADD
PATCHY MENTION ALONG THE NORTH PLATTE HOWEVER.

SUBSIDENCE ASSOCIATED WITH SHORTWAVE RIDGE AXIS WILL BUILD IN FOR
FRIDAY. THIS WILL YIELD A DRY...PARTLY SUNNY DAY. ANOTHER QUICK
MOVING...BUT DRY SHORTWAVE WILL CLIP EAST CENTRAL WYOMING AND THE
NRN NEBRASKA PANHANDLE FOR SATURDAY.

TEMPERATURES WILL REMAIN SEASONAL FOR BOTH TODAY AND TOMORROW WITH
HIGHS REACHING NR 30 WEST OF THE LARAMIE RANGE AND NR 40 OUT ON THE
ERN PLAINS. THE GRADIENT WILL LIKELY TICK UP AGAIN ON SATURDAY...SO
PRODUCING LOCALLY BREEZY CONDITIONS OVR THE WIND PRONE AREAS AND LEE-
SIDE ADIABATIC WARMING WHICH WILL BOOST TEMPS A FEW DEGREES OUT ON
THE ERN PLAINS.

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 319 AM MST THU DEC 18 2014

PRETTY ACTIVE EXTENDED PERIOD WITH WINDS ACROSS SOUTHEAST WY AND
MOUNTAIN SNOWS BEING THE PRIMARY CONCERNS. A STRONG UPPER LEVEL
JET WILL STRETCH FROM THE PACIFIC NORTHWEST INTO WY ON SUNDAY. AN
INCREASING LLVL GRADIENT WILL LIKELY RESULT IN HIGH WINDS AT LEAST
ACROSS THE WIND PRONE AREAS ON SUNDAY INTO SUNDAY NIGHT. THE GFS
SHOWS THE 850MB CAG-CPR GRADIENT RISING ABOVE 60 METERS BY 12Z SUN
AND MAXING OUT AT 85 METERS BY 12Z MON. THE MODELS HAVE BEEN
CONSISTENT WITH THIS OVER THE PAST FEW DAYS...SO OUR STRETCH OF
RELATIVELY WEAK WINDS OVER SOUTHEAST WY WILL BE COMING TO AN END.
FRONT WILL PUSH ACROSS THE AREA ON MON MORNING WITH THE SFC
PRESSURE GRADIENT BEGINNING TO RELAX. HOWEVER...WITH GOOD MIXING
AND LLVL LAPSE RATES IN THE POSTFRONTAL AIRMASS...WINDY CONDITIONS
WILL SPREAD ONTO THE PLAINS.

SEVERAL THINGS ARE ALSO COMING TOGETHER FOR A GOOD SNOW EVENT
ACROSS THE SIERRA MADRE AND SNOWY RANGES FROM SUNDAY INTO MONDAY.
THE REGION WILL BE IN THE LEFT EXIT REGION OF THE UPPER JET WITH
EXCELLENT 700-500MB MOISTURE STREAMING INTO WY FROM THE PACIFIC.
STRONG NORTHWESTERLY FLOW WILL PROVIDE GOOD OROGRAPHIC LIFT.
THE COARSE AND LIKELY UNDERDONE GFS SHOWS 1.25-1.75 INCHES OF SWE
FROM 12Z SUN THROUGH 12Z TUES. WOULD NOT BE SURPRISED TO SEE A FEW
LOCATIONS IN THE SIERRA MADRE RANGE PICK UP A FEW FEET OF SNOW IN
THIS TYPE OF PATTERN. OUTSIDE OF THE MTNS IT APPEARS THERE COULD
BE A BRIEF SHOT OF SNOW RIGHT BEHIND THE FRONT ON MON AFTN. IT
WILL DEFINITELY BE A CHILLY DAY ON MON DUE TO THE COMBINATION OF
COLDER TEMPS AND WIND. SNOW WILL DECREASE IN INTENSITY ON
TUES...THOUGH LIKELY NOT END COMPLETELY AS MOIST OROGRAPHICS
CONTINUE. ATTENTION THEN TURNS TO THE SYSTEM THAT WILL IMPACT THE
REGION IN THE WED NIGHT AND THURS TIMEFRAME. THE GFS IS MORE
PROGRESSIVE WITH THE SYSTEM COMPARED TO THE ECMWF WHICH AMPLIFIES
THE UPPER TROUGH ACROSS THE SOUTHWESTERN UNITED STATES. THIS IS
STILL OVER A WEEK AWAY...SO WILL NOT DISCUSS TOO MUCH AT THIS
TIME...HOWEVER THIS SYSTEM COULD DEFINITELY HAVE ADVERSE IMPACTS
AROUND CHRISTMAS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1045 AM MST THU DEC 18 2014

VFR EXPECTED OVERALL THROUGH THE PERIOD WITH LIGHT WINDS.  SOME FOG
MAY REDEVELOP IN THE NORTH PLATTE RIVER VALLEY TONIGHT BUT A MORE
DOWNSLOPE BREEZE SHOULD LIMIT ITS EXTENT OR DENSITY.

&&

.FIRE WEATHER...
ISSUED AT 319 AM MST THU DEC 18 2014

SEASONAL TEMPERATURES AND DRY CONDITIONS WILL
CONTINUE THROUGH THE UPCOMING WEEKEND LIMITING ANY FIRE WEATHER
CONCERNS. THE MOUNTAINS WILL SEE PERIODIC LIGHT SNOW BUT
ACCUMULATIONS WILL BE RELATIVELY LIGHT. HIGH TEMPERATURES WILL RISE
INTO THE 40S OVR THE ERN PLAINS FOR SUNDAY...BUT WITH SUFFICIENT
MOISTURE IN PLACE MINIMUM RELATIVE HUMIDITIES WILL ONLY FALL INTO
THE 40-50S. THE WINDY PATTERN WILL RETURN TO THE DISTRICT FOR SUNDAY
THROUGH TUESDAY WITH SEVERAL MORE FEET OF SNOW EXPECTED OVER THE
SNOWY AND SIERRA MADRE RANGES.

&&

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

&&

$$

UPDATE...RE
SHORT TERM...CAH
LONG TERM...ZF
AVIATION...RE
FIRE WEATHER...CAH





000
FXUS65 KCYS 181147
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
447 AM MST THU DEC 18 2014

.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 319 AM MST THU DEC 18 2014

THE ONGOING LOCALLY DENSE FOG ALONG THE NORTH PLATTE RIVER VALLEY
WILL CARRY THE GREATEST IMPACT THRU THE PERIOD. LIGHT WINDS AND
MINIMAL DISRUPTIVE MID-LEVEL CLOUDS HAS YIELDED EFFICIENT
RADIATIONAL COOLING OVERNIGHT. VISIBILITIES HAVE BOUNCED BETWEEN
1/4SM AND 1/2SM FROM TORRINGTON TO SCOTTSBLUFF TO ALLIANCE DURING
THE OVERNIGHT HOURS. LATEST SATELLITE FOG PRODUCT DOES SHOW THE
LOW CLOUDS/FOG BEGINNING TO SHIFT EAST OUT OF THE ERN CWA...BUT
KEEPS IT IN THE NORTH PLATTE RIVER VALLEY. WILL LIKELY BE ABLE TO
CANCEL BOX BUTTE FROM THE DENSE FOG ADVISORY HERE SHORTLY...BUT
WILL LEAVE THE REST GOING FOR NOW. WEST WINDS WILL FINALLY KICK IN
THIS MORNING AS EASILY DISCERNIBLE SHORTWAVE SPINS OUT OF ERN
MONTANA INTO THE WRN DAKOTAS. THIS WILL EFFECTIVELY SCOUR OUT
MORNING VALLEY FOG. SHOULD ALSO SEE THE WIND PRONE AREAS BECOME
BREEZY. OTHERWISE WEAK WESTERLY FLOW WILL WORK INTO THE AREA TODAY
WILL KEEP DRY CONDITIONS OUTSIDE OF PERHAPS SOME VERY LIGHT
MOUNTAIN SNOW SHOWERS. ALTHOUGH SOME PATCHY FOG WILL BE A
POSSIBILITY AGAIN ALONG THE NORTH PLATTE RIVER VALLEY...DO NOT
ANTICIPATE IT TO BE THE EXTENT OF WHAT IT WAS TONIGHT. DID ADD
PATCHY MENTION ALONG THE NORTH PLATTE HOWEVER.

SUBSIDENCE ASSOCIATED WITH SHORTWAVE RIDGE AXIS WILL BUILD IN FOR
FRIDAY. THIS WILL YIELD A DRY...PARTLY SUNNY DAY. ANOTHER QUICK
MOVING...BUT DRY SHORTWAVE WILL CLIP EAST CENTRAL WYOMING AND THE
NRN NEBRASKA PANHANDLE FOR SATURDAY.

TEMPERATURES WILL REMAIN SEASONAL FOR BOTH TODAY AND TOMORROW WITH
HIGHS REACHING NR 30 WEST OF THE LARAMIE RANGE AND NR 40 OUT ON THE
ERN PLAINS. THE GRADIENT WILL LIKELY TICK UP AGAIN ON SATURDAY...SO
PRODUCING LOCALLY BREEZY CONDITIONS OVR THE WIND PRONE AREAS AND LEE-
SIDE ADIABATIC WARMING WHICH WILL BOOST TEMPS A FEW DEGREES OUT ON
THE ERN PLAINS.

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 319 AM MST THU DEC 18 2014

PRETTY ACTIVE EXTENDED PERIOD WITH WINDS ACROSS SOUTHEAST WY AND
MOUNTAIN SNOWS BEING THE PRIMARY CONCERNS. A STRONG UPPER LEVEL
JET WILL STRETCH FROM THE PACIFIC NORTHWEST INTO WY ON SUNDAY. AN
INCREASING LLVL GRADIENT WILL LIKELY RESULT IN HIGH WINDS AT LEAST
ACROSS THE WIND PRONE AREAS ON SUNDAY INTO SUNDAY NIGHT. THE GFS
SHOWS THE 850MB CAG-CPR GRADIENT RISING ABOVE 60 METERS BY 12Z SUN
AND MAXING OUT AT 85 METERS BY 12Z MON. THE MODELS HAVE BEEN
CONSISTENT WITH THIS OVER THE PAST FEW DAYS...SO OUR STRETCH OF
RELATIVELY WEAK WINDS OVER SOUTHEAST WY WILL BE COMING TO AN END.
FRONT WILL PUSH ACROSS THE AREA ON MON MORNING WITH THE SFC
PRESSURE GRADIENT BEGINNING TO RELAX. HOWEVER...WITH GOOD MIXING
AND LLVL LAPSE RATES IN THE POSTFRONTAL AIRMASS...WINDY CONDITIONS
WILL SPREAD ONTO THE PLAINS.

SEVERAL THINGS ARE ALSO COMING TOGETHER FOR A GOOD SNOW EVENT
ACROSS THE SIERRA MADRE AND SNOWY RANGES FROM SUNDAY INTO MONDAY.
THE REGION WILL BE IN THE LEFT EXIT REGION OF THE UPPER JET WITH
EXCELLENT 700-500MB MOISTURE STREAMING INTO WY FROM THE PACIFIC.
STRONG NORTHWESTERLY FLOW WILL PROVIDE GOOD OROGRAPHIC LIFT.
THE COARSE AND LIKELY UNDERDONE GFS SHOWS 1.25-1.75 INCHES OF SWE
FROM 12Z SUN THROUGH 12Z TUES. WOULD NOT BE SURPRISED TO SEE A FEW
LOCATIONS IN THE SIERRA MADRE RANGE PICK UP A FEW FEET OF SNOW IN
THIS TYPE OF PATTERN. OUTSIDE OF THE MTNS IT APPEARS THERE COULD
BE A BRIEF SHOT OF SNOW RIGHT BEHIND THE FRONT ON MON AFTN. IT
WILL DEFINITELY BE A CHILLY DAY ON MON DUE TO THE COMBINATION OF
COLDER TEMPS AND WIND. SNOW WILL DECREASE IN INTENSITY ON
TUES...THOUGH LIKELY NOT END COMPLETELY AS MOIST OROGRAPHICS
CONTINUE. ATTENTION THEN TURNS TO THE SYSTEM THAT WILL IMPACT THE
REGION IN THE WED NIGHT AND THURS TIMEFRAME. THE GFS IS MORE
PROGRESSIVE WITH THE SYSTEM COMPARED TO THE ECMWF WHICH AMPLIFIES
THE UPPER TROUGH ACROSS THE SOUTHWESTERN UNITED STATES. THIS IS
STILL OVER A WEEK AWAY...SO WILL NOT DISCUSS TOO MUCH AT THIS
TIME...HOWEVER THIS SYSTEM COULD DEFINITELY HAVE ADVERSE IMPACTS
AROUND CHRISTMAS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 440 AM MST THU DEC 18 2014

IFR TO LIFR CONDITIONS WILL CONTINUE AT BFF...AIA...AND CDR OVER
THE NEXT FEW HOURS. VIS WILL BE AROUND 1SM WITH CLOUD BASES OF
100-300 FEET. WILL BEGIN TO SEE CLEARING AT AROUND 15-16Z WITH
VFR CONDITIONS THEREAFTER. OTHERWISE NOT A WHOLE LOT OF AVIATION
CONCERNS THROUGH THE REMAINDER OF THE TAF PERIOD AS WINDS WILL
GENERALLY BE LESS THAN 20 MPH. FOG COULD ONCE AGAIN DEVELOP AT BFF
BY LATE THIS EVENING...HOWEVER NOT EXPECTING IT TO BE AS DENSE OR
LONG LASTING.

&&

.FIRE WEATHER...
ISSUED AT 319 AM MST THU DEC 18 2014

SEASONAL TEMPERATURES AND DRY CONDITIONS WILL
CONTINUE THROUGH THE UPCOMING WEEKEND LIMITING ANY FIRE WEATHER
CONCERNS. THE MOUNTAINS WILL SEE PERIODIC LIGHT SNOW BUT
ACCUMULATIONS WILL BE RELATIVELY LIGHT. HIGH TEMPERATURES WILL RISE
INTO THE 40S OVR THE ERN PLAINS FOR SUNDAY...BUT WITH SUFFICIENT
MOISTURE IN PLACE MINIMUM RELATIVE HUMIDITIES WILL ONLY FALL INTO
THE 40-50S. THE WINDY PATTERN WILL RETURN TO THE DISTRICT FOR SUNDAY
THROUGH TUESDAY WITH SEVERAL MORE FEET OF SNOW EXPECTED OVER THE
SNOWY AND SIERRA MADRE RANGES.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR WYZ108.

NE...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR NEZ003-019-
     021-096.

&&

$$

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





000
FXUS65 KCYS 181147
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
447 AM MST THU DEC 18 2014

.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 319 AM MST THU DEC 18 2014

THE ONGOING LOCALLY DENSE FOG ALONG THE NORTH PLATTE RIVER VALLEY
WILL CARRY THE GREATEST IMPACT THRU THE PERIOD. LIGHT WINDS AND
MINIMAL DISRUPTIVE MID-LEVEL CLOUDS HAS YIELDED EFFICIENT
RADIATIONAL COOLING OVERNIGHT. VISIBILITIES HAVE BOUNCED BETWEEN
1/4SM AND 1/2SM FROM TORRINGTON TO SCOTTSBLUFF TO ALLIANCE DURING
THE OVERNIGHT HOURS. LATEST SATELLITE FOG PRODUCT DOES SHOW THE
LOW CLOUDS/FOG BEGINNING TO SHIFT EAST OUT OF THE ERN CWA...BUT
KEEPS IT IN THE NORTH PLATTE RIVER VALLEY. WILL LIKELY BE ABLE TO
CANCEL BOX BUTTE FROM THE DENSE FOG ADVISORY HERE SHORTLY...BUT
WILL LEAVE THE REST GOING FOR NOW. WEST WINDS WILL FINALLY KICK IN
THIS MORNING AS EASILY DISCERNIBLE SHORTWAVE SPINS OUT OF ERN
MONTANA INTO THE WRN DAKOTAS. THIS WILL EFFECTIVELY SCOUR OUT
MORNING VALLEY FOG. SHOULD ALSO SEE THE WIND PRONE AREAS BECOME
BREEZY. OTHERWISE WEAK WESTERLY FLOW WILL WORK INTO THE AREA TODAY
WILL KEEP DRY CONDITIONS OUTSIDE OF PERHAPS SOME VERY LIGHT
MOUNTAIN SNOW SHOWERS. ALTHOUGH SOME PATCHY FOG WILL BE A
POSSIBILITY AGAIN ALONG THE NORTH PLATTE RIVER VALLEY...DO NOT
ANTICIPATE IT TO BE THE EXTENT OF WHAT IT WAS TONIGHT. DID ADD
PATCHY MENTION ALONG THE NORTH PLATTE HOWEVER.

SUBSIDENCE ASSOCIATED WITH SHORTWAVE RIDGE AXIS WILL BUILD IN FOR
FRIDAY. THIS WILL YIELD A DRY...PARTLY SUNNY DAY. ANOTHER QUICK
MOVING...BUT DRY SHORTWAVE WILL CLIP EAST CENTRAL WYOMING AND THE
NRN NEBRASKA PANHANDLE FOR SATURDAY.

TEMPERATURES WILL REMAIN SEASONAL FOR BOTH TODAY AND TOMORROW WITH
HIGHS REACHING NR 30 WEST OF THE LARAMIE RANGE AND NR 40 OUT ON THE
ERN PLAINS. THE GRADIENT WILL LIKELY TICK UP AGAIN ON SATURDAY...SO
PRODUCING LOCALLY BREEZY CONDITIONS OVR THE WIND PRONE AREAS AND LEE-
SIDE ADIABATIC WARMING WHICH WILL BOOST TEMPS A FEW DEGREES OUT ON
THE ERN PLAINS.

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 319 AM MST THU DEC 18 2014

PRETTY ACTIVE EXTENDED PERIOD WITH WINDS ACROSS SOUTHEAST WY AND
MOUNTAIN SNOWS BEING THE PRIMARY CONCERNS. A STRONG UPPER LEVEL
JET WILL STRETCH FROM THE PACIFIC NORTHWEST INTO WY ON SUNDAY. AN
INCREASING LLVL GRADIENT WILL LIKELY RESULT IN HIGH WINDS AT LEAST
ACROSS THE WIND PRONE AREAS ON SUNDAY INTO SUNDAY NIGHT. THE GFS
SHOWS THE 850MB CAG-CPR GRADIENT RISING ABOVE 60 METERS BY 12Z SUN
AND MAXING OUT AT 85 METERS BY 12Z MON. THE MODELS HAVE BEEN
CONSISTENT WITH THIS OVER THE PAST FEW DAYS...SO OUR STRETCH OF
RELATIVELY WEAK WINDS OVER SOUTHEAST WY WILL BE COMING TO AN END.
FRONT WILL PUSH ACROSS THE AREA ON MON MORNING WITH THE SFC
PRESSURE GRADIENT BEGINNING TO RELAX. HOWEVER...WITH GOOD MIXING
AND LLVL LAPSE RATES IN THE POSTFRONTAL AIRMASS...WINDY CONDITIONS
WILL SPREAD ONTO THE PLAINS.

SEVERAL THINGS ARE ALSO COMING TOGETHER FOR A GOOD SNOW EVENT
ACROSS THE SIERRA MADRE AND SNOWY RANGES FROM SUNDAY INTO MONDAY.
THE REGION WILL BE IN THE LEFT EXIT REGION OF THE UPPER JET WITH
EXCELLENT 700-500MB MOISTURE STREAMING INTO WY FROM THE PACIFIC.
STRONG NORTHWESTERLY FLOW WILL PROVIDE GOOD OROGRAPHIC LIFT.
THE COARSE AND LIKELY UNDERDONE GFS SHOWS 1.25-1.75 INCHES OF SWE
FROM 12Z SUN THROUGH 12Z TUES. WOULD NOT BE SURPRISED TO SEE A FEW
LOCATIONS IN THE SIERRA MADRE RANGE PICK UP A FEW FEET OF SNOW IN
THIS TYPE OF PATTERN. OUTSIDE OF THE MTNS IT APPEARS THERE COULD
BE A BRIEF SHOT OF SNOW RIGHT BEHIND THE FRONT ON MON AFTN. IT
WILL DEFINITELY BE A CHILLY DAY ON MON DUE TO THE COMBINATION OF
COLDER TEMPS AND WIND. SNOW WILL DECREASE IN INTENSITY ON
TUES...THOUGH LIKELY NOT END COMPLETELY AS MOIST OROGRAPHICS
CONTINUE. ATTENTION THEN TURNS TO THE SYSTEM THAT WILL IMPACT THE
REGION IN THE WED NIGHT AND THURS TIMEFRAME. THE GFS IS MORE
PROGRESSIVE WITH THE SYSTEM COMPARED TO THE ECMWF WHICH AMPLIFIES
THE UPPER TROUGH ACROSS THE SOUTHWESTERN UNITED STATES. THIS IS
STILL OVER A WEEK AWAY...SO WILL NOT DISCUSS TOO MUCH AT THIS
TIME...HOWEVER THIS SYSTEM COULD DEFINITELY HAVE ADVERSE IMPACTS
AROUND CHRISTMAS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 440 AM MST THU DEC 18 2014

IFR TO LIFR CONDITIONS WILL CONTINUE AT BFF...AIA...AND CDR OVER
THE NEXT FEW HOURS. VIS WILL BE AROUND 1SM WITH CLOUD BASES OF
100-300 FEET. WILL BEGIN TO SEE CLEARING AT AROUND 15-16Z WITH
VFR CONDITIONS THEREAFTER. OTHERWISE NOT A WHOLE LOT OF AVIATION
CONCERNS THROUGH THE REMAINDER OF THE TAF PERIOD AS WINDS WILL
GENERALLY BE LESS THAN 20 MPH. FOG COULD ONCE AGAIN DEVELOP AT BFF
BY LATE THIS EVENING...HOWEVER NOT EXPECTING IT TO BE AS DENSE OR
LONG LASTING.

&&

.FIRE WEATHER...
ISSUED AT 319 AM MST THU DEC 18 2014

SEASONAL TEMPERATURES AND DRY CONDITIONS WILL
CONTINUE THROUGH THE UPCOMING WEEKEND LIMITING ANY FIRE WEATHER
CONCERNS. THE MOUNTAINS WILL SEE PERIODIC LIGHT SNOW BUT
ACCUMULATIONS WILL BE RELATIVELY LIGHT. HIGH TEMPERATURES WILL RISE
INTO THE 40S OVR THE ERN PLAINS FOR SUNDAY...BUT WITH SUFFICIENT
MOISTURE IN PLACE MINIMUM RELATIVE HUMIDITIES WILL ONLY FALL INTO
THE 40-50S. THE WINDY PATTERN WILL RETURN TO THE DISTRICT FOR SUNDAY
THROUGH TUESDAY WITH SEVERAL MORE FEET OF SNOW EXPECTED OVER THE
SNOWY AND SIERRA MADRE RANGES.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR WYZ108.

NE...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR NEZ003-019-
     021-096.

&&

$$

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




000
FXUS65 KCYS 181059
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
359 AM MST THU DEC 18 2014

.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 319 AM MST THU DEC 18 2014

HE ONGOING LOCALLY DENSE FOG ALONG THE NORTH PLATTE RIVER VALLEY
WILL CARRY THE GREATEST IMPACT THRU THE PERIOD. LIGHT WINDS AND
MINIMAL DISRUPTIVE MID-LEVEL CLOUDS HAS YIELDED EFFICIENT
RADIATIONAL COOLING OVERNIGHT. VISIBILITIES HAVE BOUNCED BETWEEN
1/4SM AND 1/2SM FROM TORRINGTON TO SCOTTSBLUFF TO ALLIANCE DURING
THE OVERNIGHT HOURS. LATEST SATELLITE FOG PRODUCT DOES SHOW THE LOW
CLOUDS/FOG BEGINNING TO SHIFT EAST OUT OF THE ERN CWA...BUT KEEPS IT
IN THE NORTH PLATTE RIVER VALLEY. WILL LIKELY BE ABLE TO CANCEL BOX
BUTTE FROM THE DENSE FOG ADVISORY HERE SHORTLY...BUT WILL LEAVE THE
REST GOING FOR NOW. WEST WINDS WILL FINALLY KICK IN THIS MORNING AS
EASILY DISCERNIBLE SHORTWAVE SPINS OUT OF ERN MONTANA INTO THE
WRN DAKOTAS. THIS WILL EFFECTIVELY SCOUR OUT MORNING VALLEY FOG.
SHOULD ALSO SEE THE WIND PRONE AREAS BECOME BREEZY. OTHERWISE WEAK
WESTERLY FLOW WILL WORK INTO THE AREA TODAY WILL KEEP DRY
CONDITIONS OUTSIDE OF PERHAPS SOME VERY LIGHT MOUNTAIN SNOW
SHOWERS. ALTHOUGH SOME PATCHY FOG WILL BE A POSSIBILITY AGAIN
ALONG THE NORTH PLATTE RIVER VALLEY...DO NOT ANTICIPATE IT TO BE
THE EXTENT OF WHAT IT WAS TONIGHT. DID ADD PATCHY MENTION ALONG
THE NORTH PLATTE HOWEVER.

SUBSIDENCE ASSOCIATED WITH SHORTWAVE RIDGE AXIS WILL BUILD IN FOR
FRIDAY. THIS WILL YIELD A DRY...PARTLY SUNNY DAY. ANOTHER QUICK
MOVING...BUT DRY SHORTWAVE WILL CLIP EAST CENTRAL WYOMING AND THE
NRN NEBRASKA PANHANDLE FOR SATURDAY.

TEMPERATURES WILL REMAIN SEASONAL FOR BOTH TODAY AND TOMORROW WITH
HIGHS REACHING NR 30 WEST OF THE LARAMIE RANGE AND NR 40 OUT ON THE
ERN PLAINS. THE GRADIENT WILL LIKELY TICK UP AGAIN ON SATURDAY...SO
PRODUCING LOCALLY BREEZY CONDITIONS OVR THE WIND PRONE AREAS AND LEE-
SIDE ADIABATIC WARMING WHICH WILL BOOST TEMPS A FEW DEGREES OUT ON
THE ERN PLAINS.

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 319 AM MST THU DEC 18 2014

PRETTY ACTIVE EXTENDED PERIOD WITH WINDS ACROSS SOUTHEAST WY AND
MOUNTAIN SNOWS BEING THE PRIMARY CONCERNS. A STRONG UPPER LEVEL
JET WILL STRETCH FROM THE PACIFIC NORTHWEST INTO WY ON SUNDAY. AN
INCREASING LLVL GRADIENT WILL LIKELY RESULT IN HIGH WINDS AT LEAST
ACROSS THE WIND PRONE AREAS ON SUNDAY INTO SUNDAY NIGHT. THE GFS
SHOWS THE 850MB CAG-CPR GRADIENT RISING ABOVE 60 METERS BY 12Z SUN
AND MAXING OUT AT 85 METERS BY 12Z MON. THE MODELS HAVE BEEN
CONSISTENT WITH THIS OVER THE PAST FEW DAYS...SO OUR STRETCH OF
RELATIVELY WEAK WINDS OVER SOUTHEAST WY WILL BE COMING TO AN END.
FRONT WILL PUSH ACROSS THE AREA ON MON MORNING WITH THE SFC
PRESSURE GRADIENT BEGINNING TO RELAX. HOWEVER...WITH GOOD MIXING
AND LLVL LAPSE RATES IN THE POSTFRONTAL AIRMASS...WINDY CONDITIONS
WILL SPREAD ONTO THE PLAINS.

SEVERAL THINGS ARE ALSO COMING TOGETHER FOR A GOOD SNOW EVENT
ACROSS THE SIERRA MADRE AND SNOWY RANGES FROM SUNDAY INTO MONDAY.
THE REGION WILL BE IN THE LEFT EXIT REGION OF THE UPPER JET WITH
EXCELLENT 700-500MB MOISTURE STREAMING INTO WY FROM THE PACIFIC.
STRONG NORTHWESTERLY FLOW WILL PROVIDE GOOD OROGRAPHIC LIFT.
THE COARSE AND LIKELY UNDERDONE GFS SHOWS 1.25-1.75 INCHES OF SWE
FROM 12Z SUN THROUGH 12Z TUES. WOULD NOT BE SURPRISED TO SEE A FEW
LOCATIONS IN THE SIERRA MADRE RANGE PICK UP A FEW FEET OF SNOW IN
THIS TYPE OF PATTERN. OUTSIDE OF THE MTNS IT APPEARS THERE COULD
BE A BRIEF SHOT OF SNOW RIGHT BEHIND THE FRONT ON MON AFTN. IT
WILL DEFINITELY BE A CHILLY DAY ON MON DUE TO THE COMBINATION OF
COLDER TEMPS AND WIND. SNOW WILL DECREASE IN INTENSITY ON
TUES...THOUGH LIKELY NOT END COMPLETELY AS MOIST OROGRAPHICS
CONTINUE. ATTENTION THEN TURNS TO THE SYSTEM THAT WILL IMPACT THE
REGION IN THE WED NIGHT AND THURS TIMEFRAME. THE GFS IS MORE
PROGRESSIVE WITH THE SYSTEM COMPARED TO THE ECMWF WHICH AMPLIFIES
THE UPPER TROUGH ACROSS THE SOUTHWESTERN UNITED STATES. THIS IS
STILL OVER A WEEK AWAY...SO WILL NOT DISCUSS TOO MUCH AT THIS
TIME...HOWEVER THIS SYSTEM COULD DEFINITELY HAVE ADVERSE IMPACTS
AROUND CHRISTMAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1031 PM MST WED DEC 17 2014

IFR/LIFR CONDITIONS WILL CONTINUE THROUGH ABOUT 15Z FOR THE NEB
PANHANDLE TERMINALS. VSBYS IN THE PLATTE RIVER VALLEY MAY BE LESS
THAN ONE QUARTER OF A MILE...ESPECIALLY AT KBFF/KTOR. CIGS WILL BE
AT OR NEAR AIRPORT MINIMUMS AROUND 200-300 FT AGL. CONDITIONS WILL
QUICKLY IMPROVE BY LATE THU MORNING OR EARLY AFTERNOON. WEST WINDS
WILL KEEP WIDESPREAD FOG AT BAY OVER SOUTHEAST WYO. HOWEVER PATCHY
DENSE FOG CANNOT BE RULED OUT OVER WESTERN CARBON COUNTY/KRWL OVER
THE NEXT FEW HOURS.

&&

.FIRE WEATHER...
ISSUED AT 319 AM MST THU DEC 18 2014

SEASONAL TEMPERATURES AND DRY CONDITIONS WILL
CONTINUE THROUGH THE UPCOMING WEEKEND LIMITING ANY FIRE WEATHER
CONCERNS. THE MOUNTAINS WILL SEE PERIODIC LIGHT SNOW BUT
ACCUMULATIONS WILL BE RELATIVELY LIGHT. HIGH TEMPERATURES WILL RISE
INTO THE 40S OVR THE ERN PLAINS FOR SUNDAY...BUT WITH SUFFICIENT
MOISTURE IN PLACE MINIMUM RELATIVE HUMIDITIES WILL ONLY FALL INTO
THE 40-50S. THE WINDY PATTERN WILL RETURN TO THE DISTRICT FOR SUNDAY
THROUGH TUESDAY WITH SEVERAL MORE FEET OF SNOW EXPECTED OVER THE
SNOWY AND SIERRA MADRE RANGES.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR WYZ108.

NE...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR NEZ003-019-
     021-096.

&&

$$

SHORT TERM...CAH
LONG TERM...ZF
AVIATION...CLH
FIRE WEATHER...CAH




000
FXUS65 KCYS 181059
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
359 AM MST THU DEC 18 2014

.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 319 AM MST THU DEC 18 2014

HE ONGOING LOCALLY DENSE FOG ALONG THE NORTH PLATTE RIVER VALLEY
WILL CARRY THE GREATEST IMPACT THRU THE PERIOD. LIGHT WINDS AND
MINIMAL DISRUPTIVE MID-LEVEL CLOUDS HAS YIELDED EFFICIENT
RADIATIONAL COOLING OVERNIGHT. VISIBILITIES HAVE BOUNCED BETWEEN
1/4SM AND 1/2SM FROM TORRINGTON TO SCOTTSBLUFF TO ALLIANCE DURING
THE OVERNIGHT HOURS. LATEST SATELLITE FOG PRODUCT DOES SHOW THE LOW
CLOUDS/FOG BEGINNING TO SHIFT EAST OUT OF THE ERN CWA...BUT KEEPS IT
IN THE NORTH PLATTE RIVER VALLEY. WILL LIKELY BE ABLE TO CANCEL BOX
BUTTE FROM THE DENSE FOG ADVISORY HERE SHORTLY...BUT WILL LEAVE THE
REST GOING FOR NOW. WEST WINDS WILL FINALLY KICK IN THIS MORNING AS
EASILY DISCERNIBLE SHORTWAVE SPINS OUT OF ERN MONTANA INTO THE
WRN DAKOTAS. THIS WILL EFFECTIVELY SCOUR OUT MORNING VALLEY FOG.
SHOULD ALSO SEE THE WIND PRONE AREAS BECOME BREEZY. OTHERWISE WEAK
WESTERLY FLOW WILL WORK INTO THE AREA TODAY WILL KEEP DRY
CONDITIONS OUTSIDE OF PERHAPS SOME VERY LIGHT MOUNTAIN SNOW
SHOWERS. ALTHOUGH SOME PATCHY FOG WILL BE A POSSIBILITY AGAIN
ALONG THE NORTH PLATTE RIVER VALLEY...DO NOT ANTICIPATE IT TO BE
THE EXTENT OF WHAT IT WAS TONIGHT. DID ADD PATCHY MENTION ALONG
THE NORTH PLATTE HOWEVER.

SUBSIDENCE ASSOCIATED WITH SHORTWAVE RIDGE AXIS WILL BUILD IN FOR
FRIDAY. THIS WILL YIELD A DRY...PARTLY SUNNY DAY. ANOTHER QUICK
MOVING...BUT DRY SHORTWAVE WILL CLIP EAST CENTRAL WYOMING AND THE
NRN NEBRASKA PANHANDLE FOR SATURDAY.

TEMPERATURES WILL REMAIN SEASONAL FOR BOTH TODAY AND TOMORROW WITH
HIGHS REACHING NR 30 WEST OF THE LARAMIE RANGE AND NR 40 OUT ON THE
ERN PLAINS. THE GRADIENT WILL LIKELY TICK UP AGAIN ON SATURDAY...SO
PRODUCING LOCALLY BREEZY CONDITIONS OVR THE WIND PRONE AREAS AND LEE-
SIDE ADIABATIC WARMING WHICH WILL BOOST TEMPS A FEW DEGREES OUT ON
THE ERN PLAINS.

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 319 AM MST THU DEC 18 2014

PRETTY ACTIVE EXTENDED PERIOD WITH WINDS ACROSS SOUTHEAST WY AND
MOUNTAIN SNOWS BEING THE PRIMARY CONCERNS. A STRONG UPPER LEVEL
JET WILL STRETCH FROM THE PACIFIC NORTHWEST INTO WY ON SUNDAY. AN
INCREASING LLVL GRADIENT WILL LIKELY RESULT IN HIGH WINDS AT LEAST
ACROSS THE WIND PRONE AREAS ON SUNDAY INTO SUNDAY NIGHT. THE GFS
SHOWS THE 850MB CAG-CPR GRADIENT RISING ABOVE 60 METERS BY 12Z SUN
AND MAXING OUT AT 85 METERS BY 12Z MON. THE MODELS HAVE BEEN
CONSISTENT WITH THIS OVER THE PAST FEW DAYS...SO OUR STRETCH OF
RELATIVELY WEAK WINDS OVER SOUTHEAST WY WILL BE COMING TO AN END.
FRONT WILL PUSH ACROSS THE AREA ON MON MORNING WITH THE SFC
PRESSURE GRADIENT BEGINNING TO RELAX. HOWEVER...WITH GOOD MIXING
AND LLVL LAPSE RATES IN THE POSTFRONTAL AIRMASS...WINDY CONDITIONS
WILL SPREAD ONTO THE PLAINS.

SEVERAL THINGS ARE ALSO COMING TOGETHER FOR A GOOD SNOW EVENT
ACROSS THE SIERRA MADRE AND SNOWY RANGES FROM SUNDAY INTO MONDAY.
THE REGION WILL BE IN THE LEFT EXIT REGION OF THE UPPER JET WITH
EXCELLENT 700-500MB MOISTURE STREAMING INTO WY FROM THE PACIFIC.
STRONG NORTHWESTERLY FLOW WILL PROVIDE GOOD OROGRAPHIC LIFT.
THE COARSE AND LIKELY UNDERDONE GFS SHOWS 1.25-1.75 INCHES OF SWE
FROM 12Z SUN THROUGH 12Z TUES. WOULD NOT BE SURPRISED TO SEE A FEW
LOCATIONS IN THE SIERRA MADRE RANGE PICK UP A FEW FEET OF SNOW IN
THIS TYPE OF PATTERN. OUTSIDE OF THE MTNS IT APPEARS THERE COULD
BE A BRIEF SHOT OF SNOW RIGHT BEHIND THE FRONT ON MON AFTN. IT
WILL DEFINITELY BE A CHILLY DAY ON MON DUE TO THE COMBINATION OF
COLDER TEMPS AND WIND. SNOW WILL DECREASE IN INTENSITY ON
TUES...THOUGH LIKELY NOT END COMPLETELY AS MOIST OROGRAPHICS
CONTINUE. ATTENTION THEN TURNS TO THE SYSTEM THAT WILL IMPACT THE
REGION IN THE WED NIGHT AND THURS TIMEFRAME. THE GFS IS MORE
PROGRESSIVE WITH THE SYSTEM COMPARED TO THE ECMWF WHICH AMPLIFIES
THE UPPER TROUGH ACROSS THE SOUTHWESTERN UNITED STATES. THIS IS
STILL OVER A WEEK AWAY...SO WILL NOT DISCUSS TOO MUCH AT THIS
TIME...HOWEVER THIS SYSTEM COULD DEFINITELY HAVE ADVERSE IMPACTS
AROUND CHRISTMAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1031 PM MST WED DEC 17 2014

IFR/LIFR CONDITIONS WILL CONTINUE THROUGH ABOUT 15Z FOR THE NEB
PANHANDLE TERMINALS. VSBYS IN THE PLATTE RIVER VALLEY MAY BE LESS
THAN ONE QUARTER OF A MILE...ESPECIALLY AT KBFF/KTOR. CIGS WILL BE
AT OR NEAR AIRPORT MINIMUMS AROUND 200-300 FT AGL. CONDITIONS WILL
QUICKLY IMPROVE BY LATE THU MORNING OR EARLY AFTERNOON. WEST WINDS
WILL KEEP WIDESPREAD FOG AT BAY OVER SOUTHEAST WYO. HOWEVER PATCHY
DENSE FOG CANNOT BE RULED OUT OVER WESTERN CARBON COUNTY/KRWL OVER
THE NEXT FEW HOURS.

&&

.FIRE WEATHER...
ISSUED AT 319 AM MST THU DEC 18 2014

SEASONAL TEMPERATURES AND DRY CONDITIONS WILL
CONTINUE THROUGH THE UPCOMING WEEKEND LIMITING ANY FIRE WEATHER
CONCERNS. THE MOUNTAINS WILL SEE PERIODIC LIGHT SNOW BUT
ACCUMULATIONS WILL BE RELATIVELY LIGHT. HIGH TEMPERATURES WILL RISE
INTO THE 40S OVR THE ERN PLAINS FOR SUNDAY...BUT WITH SUFFICIENT
MOISTURE IN PLACE MINIMUM RELATIVE HUMIDITIES WILL ONLY FALL INTO
THE 40-50S. THE WINDY PATTERN WILL RETURN TO THE DISTRICT FOR SUNDAY
THROUGH TUESDAY WITH SEVERAL MORE FEET OF SNOW EXPECTED OVER THE
SNOWY AND SIERRA MADRE RANGES.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR WYZ108.

NE...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR NEZ003-019-
     021-096.

&&

$$

SHORT TERM...CAH
LONG TERM...ZF
AVIATION...CLH
FIRE WEATHER...CAH




000
FXUS65 KCYS 181059
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
359 AM MST THU DEC 18 2014

.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 319 AM MST THU DEC 18 2014

HE ONGOING LOCALLY DENSE FOG ALONG THE NORTH PLATTE RIVER VALLEY
WILL CARRY THE GREATEST IMPACT THRU THE PERIOD. LIGHT WINDS AND
MINIMAL DISRUPTIVE MID-LEVEL CLOUDS HAS YIELDED EFFICIENT
RADIATIONAL COOLING OVERNIGHT. VISIBILITIES HAVE BOUNCED BETWEEN
1/4SM AND 1/2SM FROM TORRINGTON TO SCOTTSBLUFF TO ALLIANCE DURING
THE OVERNIGHT HOURS. LATEST SATELLITE FOG PRODUCT DOES SHOW THE LOW
CLOUDS/FOG BEGINNING TO SHIFT EAST OUT OF THE ERN CWA...BUT KEEPS IT
IN THE NORTH PLATTE RIVER VALLEY. WILL LIKELY BE ABLE TO CANCEL BOX
BUTTE FROM THE DENSE FOG ADVISORY HERE SHORTLY...BUT WILL LEAVE THE
REST GOING FOR NOW. WEST WINDS WILL FINALLY KICK IN THIS MORNING AS
EASILY DISCERNIBLE SHORTWAVE SPINS OUT OF ERN MONTANA INTO THE
WRN DAKOTAS. THIS WILL EFFECTIVELY SCOUR OUT MORNING VALLEY FOG.
SHOULD ALSO SEE THE WIND PRONE AREAS BECOME BREEZY. OTHERWISE WEAK
WESTERLY FLOW WILL WORK INTO THE AREA TODAY WILL KEEP DRY
CONDITIONS OUTSIDE OF PERHAPS SOME VERY LIGHT MOUNTAIN SNOW
SHOWERS. ALTHOUGH SOME PATCHY FOG WILL BE A POSSIBILITY AGAIN
ALONG THE NORTH PLATTE RIVER VALLEY...DO NOT ANTICIPATE IT TO BE
THE EXTENT OF WHAT IT WAS TONIGHT. DID ADD PATCHY MENTION ALONG
THE NORTH PLATTE HOWEVER.

SUBSIDENCE ASSOCIATED WITH SHORTWAVE RIDGE AXIS WILL BUILD IN FOR
FRIDAY. THIS WILL YIELD A DRY...PARTLY SUNNY DAY. ANOTHER QUICK
MOVING...BUT DRY SHORTWAVE WILL CLIP EAST CENTRAL WYOMING AND THE
NRN NEBRASKA PANHANDLE FOR SATURDAY.

TEMPERATURES WILL REMAIN SEASONAL FOR BOTH TODAY AND TOMORROW WITH
HIGHS REACHING NR 30 WEST OF THE LARAMIE RANGE AND NR 40 OUT ON THE
ERN PLAINS. THE GRADIENT WILL LIKELY TICK UP AGAIN ON SATURDAY...SO
PRODUCING LOCALLY BREEZY CONDITIONS OVR THE WIND PRONE AREAS AND LEE-
SIDE ADIABATIC WARMING WHICH WILL BOOST TEMPS A FEW DEGREES OUT ON
THE ERN PLAINS.

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 319 AM MST THU DEC 18 2014

PRETTY ACTIVE EXTENDED PERIOD WITH WINDS ACROSS SOUTHEAST WY AND
MOUNTAIN SNOWS BEING THE PRIMARY CONCERNS. A STRONG UPPER LEVEL
JET WILL STRETCH FROM THE PACIFIC NORTHWEST INTO WY ON SUNDAY. AN
INCREASING LLVL GRADIENT WILL LIKELY RESULT IN HIGH WINDS AT LEAST
ACROSS THE WIND PRONE AREAS ON SUNDAY INTO SUNDAY NIGHT. THE GFS
SHOWS THE 850MB CAG-CPR GRADIENT RISING ABOVE 60 METERS BY 12Z SUN
AND MAXING OUT AT 85 METERS BY 12Z MON. THE MODELS HAVE BEEN
CONSISTENT WITH THIS OVER THE PAST FEW DAYS...SO OUR STRETCH OF
RELATIVELY WEAK WINDS OVER SOUTHEAST WY WILL BE COMING TO AN END.
FRONT WILL PUSH ACROSS THE AREA ON MON MORNING WITH THE SFC
PRESSURE GRADIENT BEGINNING TO RELAX. HOWEVER...WITH GOOD MIXING
AND LLVL LAPSE RATES IN THE POSTFRONTAL AIRMASS...WINDY CONDITIONS
WILL SPREAD ONTO THE PLAINS.

SEVERAL THINGS ARE ALSO COMING TOGETHER FOR A GOOD SNOW EVENT
ACROSS THE SIERRA MADRE AND SNOWY RANGES FROM SUNDAY INTO MONDAY.
THE REGION WILL BE IN THE LEFT EXIT REGION OF THE UPPER JET WITH
EXCELLENT 700-500MB MOISTURE STREAMING INTO WY FROM THE PACIFIC.
STRONG NORTHWESTERLY FLOW WILL PROVIDE GOOD OROGRAPHIC LIFT.
THE COARSE AND LIKELY UNDERDONE GFS SHOWS 1.25-1.75 INCHES OF SWE
FROM 12Z SUN THROUGH 12Z TUES. WOULD NOT BE SURPRISED TO SEE A FEW
LOCATIONS IN THE SIERRA MADRE RANGE PICK UP A FEW FEET OF SNOW IN
THIS TYPE OF PATTERN. OUTSIDE OF THE MTNS IT APPEARS THERE COULD
BE A BRIEF SHOT OF SNOW RIGHT BEHIND THE FRONT ON MON AFTN. IT
WILL DEFINITELY BE A CHILLY DAY ON MON DUE TO THE COMBINATION OF
COLDER TEMPS AND WIND. SNOW WILL DECREASE IN INTENSITY ON
TUES...THOUGH LIKELY NOT END COMPLETELY AS MOIST OROGRAPHICS
CONTINUE. ATTENTION THEN TURNS TO THE SYSTEM THAT WILL IMPACT THE
REGION IN THE WED NIGHT AND THURS TIMEFRAME. THE GFS IS MORE
PROGRESSIVE WITH THE SYSTEM COMPARED TO THE ECMWF WHICH AMPLIFIES
THE UPPER TROUGH ACROSS THE SOUTHWESTERN UNITED STATES. THIS IS
STILL OVER A WEEK AWAY...SO WILL NOT DISCUSS TOO MUCH AT THIS
TIME...HOWEVER THIS SYSTEM COULD DEFINITELY HAVE ADVERSE IMPACTS
AROUND CHRISTMAS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1031 PM MST WED DEC 17 2014

IFR/LIFR CONDITIONS WILL CONTINUE THROUGH ABOUT 15Z FOR THE NEB
PANHANDLE TERMINALS. VSBYS IN THE PLATTE RIVER VALLEY MAY BE LESS
THAN ONE QUARTER OF A MILE...ESPECIALLY AT KBFF/KTOR. CIGS WILL BE
AT OR NEAR AIRPORT MINIMUMS AROUND 200-300 FT AGL. CONDITIONS WILL
QUICKLY IMPROVE BY LATE THU MORNING OR EARLY AFTERNOON. WEST WINDS
WILL KEEP WIDESPREAD FOG AT BAY OVER SOUTHEAST WYO. HOWEVER PATCHY
DENSE FOG CANNOT BE RULED OUT OVER WESTERN CARBON COUNTY/KRWL OVER
THE NEXT FEW HOURS.

&&

.FIRE WEATHER...
ISSUED AT 319 AM MST THU DEC 18 2014

SEASONAL TEMPERATURES AND DRY CONDITIONS WILL
CONTINUE THROUGH THE UPCOMING WEEKEND LIMITING ANY FIRE WEATHER
CONCERNS. THE MOUNTAINS WILL SEE PERIODIC LIGHT SNOW BUT
ACCUMULATIONS WILL BE RELATIVELY LIGHT. HIGH TEMPERATURES WILL RISE
INTO THE 40S OVR THE ERN PLAINS FOR SUNDAY...BUT WITH SUFFICIENT
MOISTURE IN PLACE MINIMUM RELATIVE HUMIDITIES WILL ONLY FALL INTO
THE 40-50S. THE WINDY PATTERN WILL RETURN TO THE DISTRICT FOR SUNDAY
THROUGH TUESDAY WITH SEVERAL MORE FEET OF SNOW EXPECTED OVER THE
SNOWY AND SIERRA MADRE RANGES.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR WYZ108.

NE...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR NEZ003-019-
     021-096.

&&

$$

SHORT TERM...CAH
LONG TERM...ZF
AVIATION...CLH
FIRE WEATHER...CAH





000
FXUS65 KCYS 180539
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1039 PM MST WED DEC 17 2014

.UPDATE...
ISSUED AT 907 PM MST WED DEC 17 2014

DECIDED TO ISSUE A DENSE FOG ADVISORY FOR THE PLATTE RIVER VALLEY
BETWEEN TORRINGTON AND BRIDGEPORT. SFC OBSERVATIONS AND AREA WEB
CAMS CONFIRM VISIBILITIES OF ONE QUARTER OF A MILE OR LESS AT TOR
AND BFF AS OF 03Z THIS EVE. BIGGEST QUESTION IS JUST HOW LONG THIS
WILL LAST AS DRIER AIR IS TRYING TO WORK IN. RECENT HIGHRES MODEL
RUNS ARE TOO QUICK TO SHIFT WINDS AROUND TO THE WEST IN THIS LOW
GRADIENT PATTERN...SO AM CONFIDENT THE PLATTE RIVER VALLEY WILL
HANG ON TO A MOIST UPVALLEY FLOW OVERNIGHT. WITH SIGNIFICANT SNOW
COVER IN SCOTTS BLUFF COUNTY...THESE AREAS SHOULD HAVE NO PROBLEM
STAYING IN THE SOUP FOR SEVERAL HOURS. THE 01Z HRRR RUN SHOWS VSBY
LESS THAN ONE HALF MILE PERSISTING THROUGH AT LEAST 12Z AND FCST
SOUNDINGS SHOW EXCELLENT LLVL MOISTURE DURING THIS TIME. FREEZING
FOG HAS ALSO HAD A TENDENCY TO CREATE LIGHT ICING THE PAST FEW
NIGHTS...SO FELT AN ADVISORY WAS WARRANTED WITH THE ADDED RISK TO
TRAVEL. ALL OTHER ASPECTS OF THE FORECAST LOOK GOOD. UPDATES AND
NPW HAVE BEEN SENT.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 351 PM MST WED DEC 17 2014

FOG AND LOW STRATUS LOOKS TO RETURN TONIGHT ACROSS THE PANHANDLE
AND ALSO CENTRAL AND WESTERN PORTIONS OF CARBON COUNTY AS
FORECAST SOUNDINGS SHOW NEARLY SATURATED LLVLS WITH LIGHT SSW
SURFACE WINDS IN PLACE FOR THESE AREAS. UPPER LEVEL WINDS WILL
REMAIN LIGHT AS WELL WITH LITTLE IN THE MEANS OF ANY DISTURBANCES
ALOFT DISRUPTING THE LOWER LEVELS...SO PERSISTENCE FORECAST SEEMS
REASONABLE. LIGHT SNOW WILL CONTINUE OVER THE MOUNTAINS IN THIS
PATTERN AS WELL...WITH GENERALLY LESS THAN AN INCH OF ACCUMULATION
EXPECTED. THINKING THAT THE FOG AND LOW STRATUS WILL NOT STICK
AROUND AS LONG TOMORROW AS TODAY/YESTERDAY AS A SHORTWAVE TROUGH
APPROACHES FROM THE PAC NW AND DEEPENS THE LEESIDE SFC PRESSURE
TROUGH...THUS INCREASING WEST WINDS ACROSS THE CWA AND NUDGING THE
LLVL MOISTURE EASTWARD. THE EXCEPTION COULD BE OUT WEST IN THE
LOWER ELEVATIONS OF CARBON COUNTY WHERE THE WESTERLY WINDS COULD
MAINTAIN INFLUX OF LLVL MOISTURE TO THIS AREA. LIKELY TO SEE WIND
GUSTS OF 30 TO 35 MPH IN THE WIND PRONE AREAS ALONG AND WEST OF
THE LARAMIE RANGE THROUGH THE DAY AS THE PRESSURE GRADIENT
STRENGTHENS IN ADVANCE OF THE UPPER TROUGH...WITH WARMING TEMPS
ACROSS THE EASTERN PLAINS WITH THESE DOWNSLOPE WINDS IN PLACE.

WINDS WILL INCREASE SLIGHTLY FOR THE WIND PRONE AREAS FOR TOMORROW
NIGHT AND FRIDAY AS THE UPPER LEVEL TROUGH MOVES OVERHEAD WITH
GUSTS OF 40 TO 50 MPH POSSIBLE THROUGH EARLY FRIDAY AFTERNOON.
EXPECTING LIGHT SNOW SHOWERS TO CONTINUE THROUGH THIS TIME ALONG
WITH SLIGHTLY WARMER TEMPS ACROSS THE PLAINS.
OTHERWISE...CONDITIONS WILL REMAIN DRY AND BREEZY THROUGH FRIDAY
NIGHT.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 351 PM MST WED DEC 17 2014

RATHER ZONAL FLOW SATURDAY WILL BECOME NWLY SATURDAY NIGHT AND
SUNDAY AS RIDGING AMPLIFIES ALONG THE WEST COAST. MAINLY DRY
OUTSIDE OF THE MTNS WHERE OROGRAPHICS SHOULD ALLOW FOR SOME SNOW
SHOWERS BOTH DAYS. LOOKING RATHER WINDY SAT NIGHT AND SUNDAY AS AN
UPPER JET MOVES INTO THE PACIFIC NW INTO THE NRN ROCKYS AND SFC
PRESSURE FALLS OCCUR OVER THE HIGH PLAINS AHEAD OF SHORTWAVE
ENERGY OVER THE PACIFIC NW. A COOL FRONT SHOULD THEN PASS ACROSS
LATE SUNDAY WITH A DECENT SURGE OF MOISTURE INCREASING SNOW SHOWER
ACTIVITY ESPECIALLY OVER THE SW PART OF THE CWA SUNDAY NIGHT AND
MONDAY. COOL AND SOMEWHAT BREEZY CONDITIONS EXPECTED FOR TUESDAY
AND WEDS AS THE CWA REMAINS UNDER NWLY FLOW ALOFT WITH SNOW
SHOWERS CONTINUING OVER THE HIGHER MTNS AS MOISTURE RIDES UP
FACING SLOPES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1031 PM MST WED DEC 17 2014

IFR/LIFR CONDITIONS WILL CONTINUE THROUGH ABOUT 15Z FOR THE NEB
PANHANDLE TERMINALS. VSBYS IN THE PLATTE RIVER VALLEY MAY BE LESS
THAN ONE QUARTER OF A MILE...ESPECIALLY AT KBFF/KTOR. CIGS WILL BE
AT OR NEAR AIRPORT MINIMUMS AROUND 200-300 FT AGL. CONDITIONS WILL
QUICKLY IMPROVE BY LATE THU MORNING OR EARLY AFTERNOON. WEST WINDS
WILL KEEP WIDESPREAD FOG AT BAY OVER SOUTHEAST WYO. HOWEVER PATCHY
DENSE FOG CANNOT BE RULED OUT OVER WESTERN CARBON COUNTY/KRWL OVER
THE NEXT FEW HOURS.

&&

.FIRE WEATHER...
ISSUED AT 351 PM MST WED DEC 17 2014

NO FIRE WEATHER CONCERNS THROUGH FRIDAY.  COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 45 PERCENT AND
WINDS WILL BE WEAK THROUGH THURSDAY. BY THURSDAY NIGHT AND
FRIDAY...WEST WINDS WILL BECOME BREEZY FOR AREAS ALONG AND WEST
OF THE LARAMIE RANGE.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR WYZ108.

NE...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR NEZ003-019-021-
     096.

&&

$$

UPDATE...CLH
SHORT TERM...RJM
LONG TERM...RE
AVIATION...CLH
FIRE WEATHER...RJM




000
FXUS65 KCYS 180539
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1039 PM MST WED DEC 17 2014

.UPDATE...
ISSUED AT 907 PM MST WED DEC 17 2014

DECIDED TO ISSUE A DENSE FOG ADVISORY FOR THE PLATTE RIVER VALLEY
BETWEEN TORRINGTON AND BRIDGEPORT. SFC OBSERVATIONS AND AREA WEB
CAMS CONFIRM VISIBILITIES OF ONE QUARTER OF A MILE OR LESS AT TOR
AND BFF AS OF 03Z THIS EVE. BIGGEST QUESTION IS JUST HOW LONG THIS
WILL LAST AS DRIER AIR IS TRYING TO WORK IN. RECENT HIGHRES MODEL
RUNS ARE TOO QUICK TO SHIFT WINDS AROUND TO THE WEST IN THIS LOW
GRADIENT PATTERN...SO AM CONFIDENT THE PLATTE RIVER VALLEY WILL
HANG ON TO A MOIST UPVALLEY FLOW OVERNIGHT. WITH SIGNIFICANT SNOW
COVER IN SCOTTS BLUFF COUNTY...THESE AREAS SHOULD HAVE NO PROBLEM
STAYING IN THE SOUP FOR SEVERAL HOURS. THE 01Z HRRR RUN SHOWS VSBY
LESS THAN ONE HALF MILE PERSISTING THROUGH AT LEAST 12Z AND FCST
SOUNDINGS SHOW EXCELLENT LLVL MOISTURE DURING THIS TIME. FREEZING
FOG HAS ALSO HAD A TENDENCY TO CREATE LIGHT ICING THE PAST FEW
NIGHTS...SO FELT AN ADVISORY WAS WARRANTED WITH THE ADDED RISK TO
TRAVEL. ALL OTHER ASPECTS OF THE FORECAST LOOK GOOD. UPDATES AND
NPW HAVE BEEN SENT.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 351 PM MST WED DEC 17 2014

FOG AND LOW STRATUS LOOKS TO RETURN TONIGHT ACROSS THE PANHANDLE
AND ALSO CENTRAL AND WESTERN PORTIONS OF CARBON COUNTY AS
FORECAST SOUNDINGS SHOW NEARLY SATURATED LLVLS WITH LIGHT SSW
SURFACE WINDS IN PLACE FOR THESE AREAS. UPPER LEVEL WINDS WILL
REMAIN LIGHT AS WELL WITH LITTLE IN THE MEANS OF ANY DISTURBANCES
ALOFT DISRUPTING THE LOWER LEVELS...SO PERSISTENCE FORECAST SEEMS
REASONABLE. LIGHT SNOW WILL CONTINUE OVER THE MOUNTAINS IN THIS
PATTERN AS WELL...WITH GENERALLY LESS THAN AN INCH OF ACCUMULATION
EXPECTED. THINKING THAT THE FOG AND LOW STRATUS WILL NOT STICK
AROUND AS LONG TOMORROW AS TODAY/YESTERDAY AS A SHORTWAVE TROUGH
APPROACHES FROM THE PAC NW AND DEEPENS THE LEESIDE SFC PRESSURE
TROUGH...THUS INCREASING WEST WINDS ACROSS THE CWA AND NUDGING THE
LLVL MOISTURE EASTWARD. THE EXCEPTION COULD BE OUT WEST IN THE
LOWER ELEVATIONS OF CARBON COUNTY WHERE THE WESTERLY WINDS COULD
MAINTAIN INFLUX OF LLVL MOISTURE TO THIS AREA. LIKELY TO SEE WIND
GUSTS OF 30 TO 35 MPH IN THE WIND PRONE AREAS ALONG AND WEST OF
THE LARAMIE RANGE THROUGH THE DAY AS THE PRESSURE GRADIENT
STRENGTHENS IN ADVANCE OF THE UPPER TROUGH...WITH WARMING TEMPS
ACROSS THE EASTERN PLAINS WITH THESE DOWNSLOPE WINDS IN PLACE.

WINDS WILL INCREASE SLIGHTLY FOR THE WIND PRONE AREAS FOR TOMORROW
NIGHT AND FRIDAY AS THE UPPER LEVEL TROUGH MOVES OVERHEAD WITH
GUSTS OF 40 TO 50 MPH POSSIBLE THROUGH EARLY FRIDAY AFTERNOON.
EXPECTING LIGHT SNOW SHOWERS TO CONTINUE THROUGH THIS TIME ALONG
WITH SLIGHTLY WARMER TEMPS ACROSS THE PLAINS.
OTHERWISE...CONDITIONS WILL REMAIN DRY AND BREEZY THROUGH FRIDAY
NIGHT.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 351 PM MST WED DEC 17 2014

RATHER ZONAL FLOW SATURDAY WILL BECOME NWLY SATURDAY NIGHT AND
SUNDAY AS RIDGING AMPLIFIES ALONG THE WEST COAST. MAINLY DRY
OUTSIDE OF THE MTNS WHERE OROGRAPHICS SHOULD ALLOW FOR SOME SNOW
SHOWERS BOTH DAYS. LOOKING RATHER WINDY SAT NIGHT AND SUNDAY AS AN
UPPER JET MOVES INTO THE PACIFIC NW INTO THE NRN ROCKYS AND SFC
PRESSURE FALLS OCCUR OVER THE HIGH PLAINS AHEAD OF SHORTWAVE
ENERGY OVER THE PACIFIC NW. A COOL FRONT SHOULD THEN PASS ACROSS
LATE SUNDAY WITH A DECENT SURGE OF MOISTURE INCREASING SNOW SHOWER
ACTIVITY ESPECIALLY OVER THE SW PART OF THE CWA SUNDAY NIGHT AND
MONDAY. COOL AND SOMEWHAT BREEZY CONDITIONS EXPECTED FOR TUESDAY
AND WEDS AS THE CWA REMAINS UNDER NWLY FLOW ALOFT WITH SNOW
SHOWERS CONTINUING OVER THE HIGHER MTNS AS MOISTURE RIDES UP
FACING SLOPES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1031 PM MST WED DEC 17 2014

IFR/LIFR CONDITIONS WILL CONTINUE THROUGH ABOUT 15Z FOR THE NEB
PANHANDLE TERMINALS. VSBYS IN THE PLATTE RIVER VALLEY MAY BE LESS
THAN ONE QUARTER OF A MILE...ESPECIALLY AT KBFF/KTOR. CIGS WILL BE
AT OR NEAR AIRPORT MINIMUMS AROUND 200-300 FT AGL. CONDITIONS WILL
QUICKLY IMPROVE BY LATE THU MORNING OR EARLY AFTERNOON. WEST WINDS
WILL KEEP WIDESPREAD FOG AT BAY OVER SOUTHEAST WYO. HOWEVER PATCHY
DENSE FOG CANNOT BE RULED OUT OVER WESTERN CARBON COUNTY/KRWL OVER
THE NEXT FEW HOURS.

&&

.FIRE WEATHER...
ISSUED AT 351 PM MST WED DEC 17 2014

NO FIRE WEATHER CONCERNS THROUGH FRIDAY.  COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 45 PERCENT AND
WINDS WILL BE WEAK THROUGH THURSDAY. BY THURSDAY NIGHT AND
FRIDAY...WEST WINDS WILL BECOME BREEZY FOR AREAS ALONG AND WEST
OF THE LARAMIE RANGE.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR WYZ108.

NE...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR NEZ003-019-021-
     096.

&&

$$

UPDATE...CLH
SHORT TERM...RJM
LONG TERM...RE
AVIATION...CLH
FIRE WEATHER...RJM





000
FXUS65 KCYS 180419
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
919 PM MST WED DEC 17 2014

.UPDATE...
ISSUED AT 907 PM MST WED DEC 17 2014

DECIDED TO ISSUE A DENSE FOG ADVISORY FOR THE PLATTE RIVER VALLEY
BETWEEN TORRINGTON AND BRIDGEPORT. SFC OBSERVATIONS AND AREA WEB
CAMS CONFIRM VISIBILITIES OF ONE QUARTER OF A MILE OR LESS AT TOR
AND BFF AS OF 03Z THIS EVE. BIGGEST QUESTION IS JUST HOW LONG THIS
WILL LAST AS DRIER AIR IS TRYING TO WORK IN. RECENT HIGHRES MODEL
RUNS ARE TOO QUICK TO SHIFT WINDS AROUND TO THE WEST IN THIS LOW
GRADIENT PATTERN...SO AM CONFIDENT THE PLATTE RIVER VALLEY WILL
HANG ON TO A MOIST UPVALLEY FLOW OVERNIGHT. WITH SIGNIFICANT SNOW
COVER IN SCOTTS BLUFF COUNTY...THESE AREAS SHOULD HAVE NO PROBLEM
STAYING IN THE SOUP FOR SEVERAL HOURS. THE 01Z HRRR RUN SHOWS VSBY
LESS THAN ONE HALF MILE PERSISTING THROUGH AT LEAST 12Z AND FCST
SOUNDINGS SHOW EXCELLENT LLVL MOISTURE DURING THIS TIME. FREEZING
FOG HAS ALSO HAD A TENDENCY TO CREATE LIGHT ICING THE PAST FEW
NIGHTS...SO FELT AN ADVISORY WAS WARRANTED WITH THE ADDED RISK TO
TRAVEL. ALL OTHER ASPECTS OF THE FORECAST LOOK GOOD. UPDATES AND
NPW HAVE BEEN SENT.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 351 PM MST WED DEC 17 2014

FOG AND LOW STRATUS LOOKS TO RETURN TONIGHT ACROSS THE PANHANDLE
AND ALSO CENTRAL AND WESTERN PORTIONS OF CARBON COUNTY AS
FORECAST SOUNDINGS SHOW NEARLY SATURATED LLVLS WITH LIGHT SSW
SURFACE WINDS IN PLACE FOR THESE AREAS. UPPER LEVEL WINDS WILL
REMAIN LIGHT AS WELL WITH LITTLE IN THE MEANS OF ANY DISTURBANCES
ALOFT DISRUPTING THE LOWER LEVELS...SO PERSISTENCE FORECAST SEEMS
REASONABLE. LIGHT SNOW WILL CONTINUE OVER THE MOUNTAINS IN THIS
PATTERN AS WELL...WITH GENERALLY LESS THAN AN INCH OF ACCUMULATION
EXPECTED. THINKING THAT THE FOG AND LOW STRATUS WILL NOT STICK
AROUND AS LONG TOMORROW AS TODAY/YESTERDAY AS A SHORTWAVE TROUGH
APPROACHES FROM THE PAC NW AND DEEPENS THE LEESIDE SFC PRESSURE
TROUGH...THUS INCREASING WEST WINDS ACROSS THE CWA AND NUDGING THE
LLVL MOISTURE EASTWARD. THE EXCEPTION COULD BE OUT WEST IN THE
LOWER ELEVATIONS OF CARBON COUNTY WHERE THE WESTERLY WINDS COULD
MAINTAIN INFLUX OF LLVL MOISTURE TO THIS AREA. LIKELY TO SEE WIND
GUSTS OF 30 TO 35 MPH IN THE WIND PRONE AREAS ALONG AND WEST OF
THE LARAMIE RANGE THROUGH THE DAY AS THE PRESSURE GRADIENT
STRENGTHENS IN ADVANCE OF THE UPPER TROUGH...WITH WARMING TEMPS
ACROSS THE EASTERN PLAINS WITH THESE DOWNSLOPE WINDS IN PLACE.

WINDS WILL INCREASE SLIGHTLY FOR THE WIND PRONE AREAS FOR TOMORROW
NIGHT AND FRIDAY AS THE UPPER LEVEL TROUGH MOVES OVERHEAD WITH
GUSTS OF 40 TO 50 MPH POSSIBLE THROUGH EARLY FRIDAY AFTERNOON.
EXPECTING LIGHT SNOW SHOWERS TO CONTINUE THROUGH THIS TIME ALONG
WITH SLIGHTLY WARMER TEMPS ACROSS THE PLAINS.
OTHERWISE...CONDITIONS WILL REMAIN DRY AND BREEZY THROUGH FRIDAY
NIGHT.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 351 PM MST WED DEC 17 2014

RATHER ZONAL FLOW SATURDAY WILL BECOME NWLY SATURDAY NIGHT AND
SUNDAY AS RIDGING AMPLIFIES ALONG THE WEST COAST. MAINLY DRY
OUTSIDE OF THE MTNS WHERE OROGRAPHICS SHOULD ALLOW FOR SOME SNOW
SHOWERS BOTH DAYS. LOOKING RATHER WINDY SAT NIGHT AND SUNDAY AS AN
UPPER JET MOVES INTO THE PACIFIC NW INTO THE NRN ROCKYS AND SFC
PRESSURE FALLS OCCUR OVER THE HIGH PLAINS AHEAD OF SHORTWAVE
ENERGY OVER THE PACIFIC NW. A COOL FRONT SHOULD THEN PASS ACROSS
LATE SUNDAY WITH A DECENT SURGE OF MOISTURE INCREASING SNOW SHOWER
ACTIVITY ESPECIALLY OVER THE SW PART OF THE CWA SUNDAY NIGHT AND
MONDAY. COOL AND SOMEWHAT BREEZY CONDITIONS EXPECTED FOR TUESDAY
AND WEDS AS THE CWA REMAINS UNDER NWLY FLOW ALOFT WITH SNOW
SHOWERS CONTINUING OVER THE HIGHER MTNS AS MOISTURE RIDES UP
FACING SLOPES.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 351 PM MST WED DEC 17 2014

VFR EXPECTED OVER SE WY TERMINALS THROUGH THE PERIOD.  IFR TO MVFR
CIGS/VSBYS LIKELY TO SPREAD BACK ACROSS MUCH OF NEB PANHANDLE THIS
EVENING DUE TO SNOW COVER AND WEAK UPSLOPE FLOW.


&&

.FIRE WEATHER...
ISSUED AT 351 PM MST WED DEC 17 2014

NO FIRE WEATHER CONCERNS THROUGH FRIDAY.  COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 45 PERCENT AND
WINDS WILL BE WEAK THROUGH THURSDAY. BY THURSDAY NIGHT AND
FRIDAY...WEST WINDS WILL BECOME BREEZY FOR AREAS ALONG AND WEST
OF THE LARAMIE RANGE.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR WYZ108.

NE...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR NEZ003-019-021-
     096.

&&

$$

UPDATE...CLH
SHORT TERM...RJM
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...RJM




000
FXUS65 KCYS 180419
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
919 PM MST WED DEC 17 2014

.UPDATE...
ISSUED AT 907 PM MST WED DEC 17 2014

DECIDED TO ISSUE A DENSE FOG ADVISORY FOR THE PLATTE RIVER VALLEY
BETWEEN TORRINGTON AND BRIDGEPORT. SFC OBSERVATIONS AND AREA WEB
CAMS CONFIRM VISIBILITIES OF ONE QUARTER OF A MILE OR LESS AT TOR
AND BFF AS OF 03Z THIS EVE. BIGGEST QUESTION IS JUST HOW LONG THIS
WILL LAST AS DRIER AIR IS TRYING TO WORK IN. RECENT HIGHRES MODEL
RUNS ARE TOO QUICK TO SHIFT WINDS AROUND TO THE WEST IN THIS LOW
GRADIENT PATTERN...SO AM CONFIDENT THE PLATTE RIVER VALLEY WILL
HANG ON TO A MOIST UPVALLEY FLOW OVERNIGHT. WITH SIGNIFICANT SNOW
COVER IN SCOTTS BLUFF COUNTY...THESE AREAS SHOULD HAVE NO PROBLEM
STAYING IN THE SOUP FOR SEVERAL HOURS. THE 01Z HRRR RUN SHOWS VSBY
LESS THAN ONE HALF MILE PERSISTING THROUGH AT LEAST 12Z AND FCST
SOUNDINGS SHOW EXCELLENT LLVL MOISTURE DURING THIS TIME. FREEZING
FOG HAS ALSO HAD A TENDENCY TO CREATE LIGHT ICING THE PAST FEW
NIGHTS...SO FELT AN ADVISORY WAS WARRANTED WITH THE ADDED RISK TO
TRAVEL. ALL OTHER ASPECTS OF THE FORECAST LOOK GOOD. UPDATES AND
NPW HAVE BEEN SENT.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 351 PM MST WED DEC 17 2014

FOG AND LOW STRATUS LOOKS TO RETURN TONIGHT ACROSS THE PANHANDLE
AND ALSO CENTRAL AND WESTERN PORTIONS OF CARBON COUNTY AS
FORECAST SOUNDINGS SHOW NEARLY SATURATED LLVLS WITH LIGHT SSW
SURFACE WINDS IN PLACE FOR THESE AREAS. UPPER LEVEL WINDS WILL
REMAIN LIGHT AS WELL WITH LITTLE IN THE MEANS OF ANY DISTURBANCES
ALOFT DISRUPTING THE LOWER LEVELS...SO PERSISTENCE FORECAST SEEMS
REASONABLE. LIGHT SNOW WILL CONTINUE OVER THE MOUNTAINS IN THIS
PATTERN AS WELL...WITH GENERALLY LESS THAN AN INCH OF ACCUMULATION
EXPECTED. THINKING THAT THE FOG AND LOW STRATUS WILL NOT STICK
AROUND AS LONG TOMORROW AS TODAY/YESTERDAY AS A SHORTWAVE TROUGH
APPROACHES FROM THE PAC NW AND DEEPENS THE LEESIDE SFC PRESSURE
TROUGH...THUS INCREASING WEST WINDS ACROSS THE CWA AND NUDGING THE
LLVL MOISTURE EASTWARD. THE EXCEPTION COULD BE OUT WEST IN THE
LOWER ELEVATIONS OF CARBON COUNTY WHERE THE WESTERLY WINDS COULD
MAINTAIN INFLUX OF LLVL MOISTURE TO THIS AREA. LIKELY TO SEE WIND
GUSTS OF 30 TO 35 MPH IN THE WIND PRONE AREAS ALONG AND WEST OF
THE LARAMIE RANGE THROUGH THE DAY AS THE PRESSURE GRADIENT
STRENGTHENS IN ADVANCE OF THE UPPER TROUGH...WITH WARMING TEMPS
ACROSS THE EASTERN PLAINS WITH THESE DOWNSLOPE WINDS IN PLACE.

WINDS WILL INCREASE SLIGHTLY FOR THE WIND PRONE AREAS FOR TOMORROW
NIGHT AND FRIDAY AS THE UPPER LEVEL TROUGH MOVES OVERHEAD WITH
GUSTS OF 40 TO 50 MPH POSSIBLE THROUGH EARLY FRIDAY AFTERNOON.
EXPECTING LIGHT SNOW SHOWERS TO CONTINUE THROUGH THIS TIME ALONG
WITH SLIGHTLY WARMER TEMPS ACROSS THE PLAINS.
OTHERWISE...CONDITIONS WILL REMAIN DRY AND BREEZY THROUGH FRIDAY
NIGHT.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 351 PM MST WED DEC 17 2014

RATHER ZONAL FLOW SATURDAY WILL BECOME NWLY SATURDAY NIGHT AND
SUNDAY AS RIDGING AMPLIFIES ALONG THE WEST COAST. MAINLY DRY
OUTSIDE OF THE MTNS WHERE OROGRAPHICS SHOULD ALLOW FOR SOME SNOW
SHOWERS BOTH DAYS. LOOKING RATHER WINDY SAT NIGHT AND SUNDAY AS AN
UPPER JET MOVES INTO THE PACIFIC NW INTO THE NRN ROCKYS AND SFC
PRESSURE FALLS OCCUR OVER THE HIGH PLAINS AHEAD OF SHORTWAVE
ENERGY OVER THE PACIFIC NW. A COOL FRONT SHOULD THEN PASS ACROSS
LATE SUNDAY WITH A DECENT SURGE OF MOISTURE INCREASING SNOW SHOWER
ACTIVITY ESPECIALLY OVER THE SW PART OF THE CWA SUNDAY NIGHT AND
MONDAY. COOL AND SOMEWHAT BREEZY CONDITIONS EXPECTED FOR TUESDAY
AND WEDS AS THE CWA REMAINS UNDER NWLY FLOW ALOFT WITH SNOW
SHOWERS CONTINUING OVER THE HIGHER MTNS AS MOISTURE RIDES UP
FACING SLOPES.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 351 PM MST WED DEC 17 2014

VFR EXPECTED OVER SE WY TERMINALS THROUGH THE PERIOD.  IFR TO MVFR
CIGS/VSBYS LIKELY TO SPREAD BACK ACROSS MUCH OF NEB PANHANDLE THIS
EVENING DUE TO SNOW COVER AND WEAK UPSLOPE FLOW.


&&

.FIRE WEATHER...
ISSUED AT 351 PM MST WED DEC 17 2014

NO FIRE WEATHER CONCERNS THROUGH FRIDAY.  COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 45 PERCENT AND
WINDS WILL BE WEAK THROUGH THURSDAY. BY THURSDAY NIGHT AND
FRIDAY...WEST WINDS WILL BECOME BREEZY FOR AREAS ALONG AND WEST
OF THE LARAMIE RANGE.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR WYZ108.

NE...DENSE FOG ADVISORY UNTIL 8 AM MST THURSDAY FOR NEZ003-019-021-
     096.

&&

$$

UPDATE...CLH
SHORT TERM...RJM
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...RJM





000
FXUS65 KCYS 172251
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
351 PM MST WED DEC 17 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 351 PM MST WED DEC 17 2014

FOG AND LOW STRATUS LOOKS TO RETURN TONIGHT ACROSS THE PANHANDLE
AND ALSO CENTRAL AND WESTERN PORTIONS OF CARBON COUNTY AS
FORECAST SOUNDINGS SHOW NEARLY SATURATED LLVLS WITH LIGHT SSW
SURFACE WINDS IN PLACE FOR THESE AREAS. UPPER LEVEL WINDS WILL
REMAIN LIGHT AS WELL WITH LITTLE IN THE MEANS OF ANY DISTURBANCES
ALOFT DISRUPTING THE LOWER LEVELS...SO PERSISTENCE FORECAST SEEMS
REASONABLE. LIGHT SNOW WILL CONTINUE OVER THE MOUNTAINS IN THIS
PATTERN AS WELL...WITH GENERALLY LESS THAN AN INCH OF ACCUMULATION
EXPECTED. THINKING THAT THE FOG AND LOW STRATUS WILL NOT STICK
AROUND AS LONG TOMORROW AS TODAY/YESTERDAY AS A SHORTWAVE TROUGH
APPROACHES FROM THE PAC NW AND DEEPENS THE LEESIDE SFC PRESSURE
TROUGH...THUS INCREASING WEST WINDS ACROSS THE CWA AND NUDGING THE
LLVL MOISTURE EASTWARD. THE EXCEPTION COULD BE OUT WEST IN THE
LOWER ELEVATIONS OF CARBON COUNTY WHERE THE WESTERLY WINDS COULD
MAINTAIN INFLUX OF LLVL MOISTURE TO THIS AREA. LIKELY TO SEE WIND
GUSTS OF 30 TO 35 MPH IN THE WIND PRONE AREAS ALONG AND WEST OF
THE LARAMIE RANGE THROUGH THE DAY AS THE PRESSURE GRADIENT
STRENGTHENS IN ADVANCE OF THE UPPER TROUGH...WITH WARMING TEMPS
ACROSS THE EASTERN PLAINS WITH THESE DOWNSLOPE WINDS IN PLACE.

WINDS WILL INCREASE SLIGHTLY FOR THE WIND PRONE AREAS FOR TOMORROW
NIGHT AND FRIDAY AS THE UPPER LEVEL TROUGH MOVES OVERHEAD WITH
GUSTS OF 40 TO 50 MPH POSSIBLE THROUGH EARLY FRIDAY AFTERNOON.
EXPECTING LIGHT SNOW SHOWERS TO CONTINUE THROUGH THIS TIME ALONG
WITH SLIGHTLY WARMER TEMPS ACROSS THE PLAINS.
OTHERWISE...CONDITIONSWILL REMAIN DRY AND BREEZY THROUGH FRIDAY
NIGHT.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 351 PM MST WED DEC 17 2014

RATHER ZONAL FLOW SATURDAY WILL BECOME NWLY SATURDAY NIGHT AND
SUNDAY AS RIDGING AMPLIFIES ALONG THE WEST COAST. MAINLY DRY
OUTSIDE OF THE MTNS WHERE OROGRAPHICS SHOULD ALLOW FOR SOME SNOW
SHOWERS BOTH DAYS. LOOKING RATHER WINDY SAT NIGHT AND SUNDAY AS AN
UPPER JET MOVES INTO THE PACIFIC NW INTO THE NRN ROCKYS AND SFC
PRESSURE FALLS OCCUR OVER THE HIGH PLAINS AHEAD OF SHORTWAVE
ENERGY OVER THE PACIFIC NW. A COOL FRONT SHOULD THEN PASS ACROSS
LATE SUNDAY WITH A DECENT SURGE OF MOISTURE INCREASING SNOW SHOWER
ACTIVITY ESPECIALLY OVER THE SW PART OF THE CWA SUNDAY NIGHT AND
MONDAY. COOL AND SOMEWHAT BREEZY CONDITIONS EXPECTED FOR TUESDAY
AND WEDS AS THE CWA REMAINS UNDER NWLY FLOW ALOFT WITH SNOW
SHOWERS CONTINUING OVER THE HIGHER MTNS AS MOISTURE RIDES UP
FACING SLOPES.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 351 PM MST WED DEC 17 2014

VFR EXPECTED OVER SE WY TERMINALS THROUGH THE PERIOD.  IFR TO MVFR
CIGS/VSBYS LIKELY TO SPREAD BACK ACROSS MUCH OF NEB PANHANDLE THIS
EVENING DUE TO SNOW COVER AND WEAK UPSLOPE FLOW.

&&

.FIRE WEATHER...
ISSUED AT 351 PM MST WED DEC 17 2014

NO FIRE WEATHER CONCERNS THROUGH FRIDAY.  COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 45 PERCENT AND
WINDS WILL BE WEAK THROUGH THURSDAY. BY THURSDAY NIGHT AND
FRIDAY...WEST WINDS WILL BECOME BREEZY FOR AREAS ALONG AND WEST
OF THE LARAMIE RANGE.

&&

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

$$

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




000
FXUS65 KCYS 172251
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
351 PM MST WED DEC 17 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 351 PM MST WED DEC 17 2014

FOG AND LOW STRATUS LOOKS TO RETURN TONIGHT ACROSS THE PANHANDLE
AND ALSO CENTRAL AND WESTERN PORTIONS OF CARBON COUNTY AS
FORECAST SOUNDINGS SHOW NEARLY SATURATED LLVLS WITH LIGHT SSW
SURFACE WINDS IN PLACE FOR THESE AREAS. UPPER LEVEL WINDS WILL
REMAIN LIGHT AS WELL WITH LITTLE IN THE MEANS OF ANY DISTURBANCES
ALOFT DISRUPTING THE LOWER LEVELS...SO PERSISTENCE FORECAST SEEMS
REASONABLE. LIGHT SNOW WILL CONTINUE OVER THE MOUNTAINS IN THIS
PATTERN AS WELL...WITH GENERALLY LESS THAN AN INCH OF ACCUMULATION
EXPECTED. THINKING THAT THE FOG AND LOW STRATUS WILL NOT STICK
AROUND AS LONG TOMORROW AS TODAY/YESTERDAY AS A SHORTWAVE TROUGH
APPROACHES FROM THE PAC NW AND DEEPENS THE LEESIDE SFC PRESSURE
TROUGH...THUS INCREASING WEST WINDS ACROSS THE CWA AND NUDGING THE
LLVL MOISTURE EASTWARD. THE EXCEPTION COULD BE OUT WEST IN THE
LOWER ELEVATIONS OF CARBON COUNTY WHERE THE WESTERLY WINDS COULD
MAINTAIN INFLUX OF LLVL MOISTURE TO THIS AREA. LIKELY TO SEE WIND
GUSTS OF 30 TO 35 MPH IN THE WIND PRONE AREAS ALONG AND WEST OF
THE LARAMIE RANGE THROUGH THE DAY AS THE PRESSURE GRADIENT
STRENGTHENS IN ADVANCE OF THE UPPER TROUGH...WITH WARMING TEMPS
ACROSS THE EASTERN PLAINS WITH THESE DOWNSLOPE WINDS IN PLACE.

WINDS WILL INCREASE SLIGHTLY FOR THE WIND PRONE AREAS FOR TOMORROW
NIGHT AND FRIDAY AS THE UPPER LEVEL TROUGH MOVES OVERHEAD WITH
GUSTS OF 40 TO 50 MPH POSSIBLE THROUGH EARLY FRIDAY AFTERNOON.
EXPECTING LIGHT SNOW SHOWERS TO CONTINUE THROUGH THIS TIME ALONG
WITH SLIGHTLY WARMER TEMPS ACROSS THE PLAINS.
OTHERWISE...CONDITIONSWILL REMAIN DRY AND BREEZY THROUGH FRIDAY
NIGHT.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 351 PM MST WED DEC 17 2014

RATHER ZONAL FLOW SATURDAY WILL BECOME NWLY SATURDAY NIGHT AND
SUNDAY AS RIDGING AMPLIFIES ALONG THE WEST COAST. MAINLY DRY
OUTSIDE OF THE MTNS WHERE OROGRAPHICS SHOULD ALLOW FOR SOME SNOW
SHOWERS BOTH DAYS. LOOKING RATHER WINDY SAT NIGHT AND SUNDAY AS AN
UPPER JET MOVES INTO THE PACIFIC NW INTO THE NRN ROCKYS AND SFC
PRESSURE FALLS OCCUR OVER THE HIGH PLAINS AHEAD OF SHORTWAVE
ENERGY OVER THE PACIFIC NW. A COOL FRONT SHOULD THEN PASS ACROSS
LATE SUNDAY WITH A DECENT SURGE OF MOISTURE INCREASING SNOW SHOWER
ACTIVITY ESPECIALLY OVER THE SW PART OF THE CWA SUNDAY NIGHT AND
MONDAY. COOL AND SOMEWHAT BREEZY CONDITIONS EXPECTED FOR TUESDAY
AND WEDS AS THE CWA REMAINS UNDER NWLY FLOW ALOFT WITH SNOW
SHOWERS CONTINUING OVER THE HIGHER MTNS AS MOISTURE RIDES UP
FACING SLOPES.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 351 PM MST WED DEC 17 2014

VFR EXPECTED OVER SE WY TERMINALS THROUGH THE PERIOD.  IFR TO MVFR
CIGS/VSBYS LIKELY TO SPREAD BACK ACROSS MUCH OF NEB PANHANDLE THIS
EVENING DUE TO SNOW COVER AND WEAK UPSLOPE FLOW.

&&

.FIRE WEATHER...
ISSUED AT 351 PM MST WED DEC 17 2014

NO FIRE WEATHER CONCERNS THROUGH FRIDAY.  COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 45 PERCENT AND
WINDS WILL BE WEAK THROUGH THURSDAY. BY THURSDAY NIGHT AND
FRIDAY...WEST WINDS WILL BECOME BREEZY FOR AREAS ALONG AND WEST
OF THE LARAMIE RANGE.

&&

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

$$

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





000
FXUS65 KCYS 171714
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1013 AM MST WED DEC 17 2014

.SHORT TERM...(TODAY AND THROUGH FRIDAY NIGHT)
ISSUED AT 350 AM MST WED DEC 17 2014

SPLIT FLOW PATTERN WILL BE IN PLACE ACROSS THE REGION TODAY. THERE
IS A WEAK SHORTWAVE MOVING TO THE NORTH OF THE CWA AND A MORE
POTENT AND MOISTURE LADEN SHORTWAVE OVER NORTHERN NEW MEXICO. THIS
PUTS US IN THE MIDDLE BETWEEN THE SYSTEMS. THE MODELS CONTINUE TO
INDICATE THAT THE BEST MOISTURE ASSOCIATED WITH THE SOUTHERN WAVE
WILL BE SOUTH INTO COLORADO. THUS...ONLY HAVE SLIGHT CHANCE TO
CHANCE POPS OVER THE SIERRA MADRE AND SNOWY RANGES THROUGH THE
DAY. THE ONLY NOTICEABLE IMPACT OVER MUCH OF THE CWA WILL BE AN
INCREASE IN MID AND HIGH LEVEL CLOUDS. THE EASTERN ZONES WILL BE
DEALING WITH STRATUS THROUGH THE MORNING AS WINDS TO THE EAST OF
THE SFC TROUGH ARE SOUTHERLY OUT THERE. ANOTHER COOL DAY IS IN
STORE AND DROPPED HIGHS A FEW DEGREES OVER THE PANHANDLE WHERE
SNOW COVER IS STILL PRESENT. WINDS WILL ONCE AGAIN BE RATHER WEAK
WITH MINIMAL LLVL GRADIENTS AND FLOW ALOFT.

THERE WILL NOT BE MUCH CHANGE IN THE PATTERN THROUGH THE REMAINDER
OF THE SHORT TERM. THE CAG-CPR GRADIENT...WHICH STAYS BELOW 25
METERS THROUGH THURSDAY NIGHT...WILL INCREASE TO 35-40 METERS BY
FRI MORNING AND AFTN. THUS...WILL BEGIN TO SEE WINDS BECOME BREEZY
OVER MUCH OF SOUTHEAST WY BY FRI AND LOCALLY WINDY IN THE WIND
PRONE SPOTS. TEMPERATURES WILL REMAIN CONSTANT THROUGH
FRI...GENERALLY AT SEASONAL NORMS FOR MID DEC. SLIGHT CHANCE POPS
WILL BE CONFINED TO THE MTNS WEST OF THE LARAMIE RANGE.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 350 AM MST WED DEC 17 2014

THE MAIN HIGHLIGHTS FOR THE WEEKEND AND EARLY NEXT WEEK WILL BE THE
RETURN TO BREEZY TO LOCALLY WINDY CONDITIONS ACROSS SOUTHEAST
WYOMING ALONG WITH A GOOD SHOT OF MOUNTAIN SNOW LATE SUNDAY THROUGH
MONDAY. WEAK NON-DESCRIPT WEST/NORTHWEST FLOW WILL BE IN PLACE ON
SATURDAY. WEAK SHORTWAVE ENERGY WILL BE EMBEDDED WITHIN THE
FLOW...BUT ASIDE FROM LIGHT SNOW SHOWER CHANCES FOR THE SNOWY/SIERRA
MADRES EXPECT LITTLE IF ANY SENSIBLE WEATHER IMPACT. SATURDAY WILL
BE THE LAST RELATIVELY WIND-FREE DAY ACROSS SOUTHEAST WYOMING BEFORE
THE WIND MACHINE GETS CRANKING SUN-TUE.

00Z MODELS HAVE TRENDED FASTER WITH THE TIMING OF THE NOSE OF THE
ANTICYCLONIC JET...NOW PUSHING IT IN DURING THE DAY ON SUNDAY. SO
WILL SEE A STEADY INCREASE IN WIND SPEEDS...FIRST ACROSS THE WIND
PRONE AREAS SATURDAY NIGHT BEFORE SPILLING INTO LOWER ELEVATIONS
SUNDAY AND MONDAY. H7 WIND PROGS CONTINUE TO REACH 50-60 KNOTS
DURING THIS PERIOD WHICH SHOULD BE ENOUGH TO NECESSITATE A WIND
HIGHLIGHT AT LEAST FOR THE WIND PRONE AREAS WITH TIME. AREAS AWAY
FROM THE TYPICALLY WINDY AREAS ARE MORE TRICKY AND TYPICALLY TIED TO
MAGNITUDE OF PBL WHICH CAN BE AFFECTED BY A NUMBER OF THINGS
INCLUDING CLOUD COVER. AT THE VERY LEAST WILL SEE WIDESPREAD BREEZY
CONDITIONS EVEN SPREADING OVER INTO THE WRN NEBRASKA PANHANDLE MON-
TUE. THE GOOD NEWS WITH THE RETURN OF THE WIND WILL BE THAT
TEMPERATURES WILL WARM AROUND 5F AREA WIDE WITH DEEPER LLVL MIXING.
HIGH TEMPERATURES ON MONDAY WILL RETURN TO NR 40 WEST OF THE LARAMIE
RANGE AND MID 40S EAST.

MODELS CLIP THE AREA WITH A SERIES OF SHORTWAVE TROUGHS SUNDAY AND
MONDAY. MOISTURE ADVECTED BY THESE WILL COMBINE WITH FAVORABLE
OROGRAPHIC FLOW TO PRODUCE A GOOD CHANCE FOR ACCUMULATING MOUNTAIN
SNOWS ESPECIALLY LATE SUNDAY THROUGH MONDAY. AMOUNTS WOULD ADD UP IN
A HURRY IN THIS PATTERN AND IF TRENDS CONTINUE WOULD PROBABLY NEED
SOME SORT OF A WINTER HIGHLIGHT THERE IN TIME. AREAS OUTSIDE OF THE
MOUNTAINS MAY SEE SOME PRECIPITATION AS WELL ESPECIALLY SUNDAY NIGHT
AND MONDAY...THOUGH DO NOT SEE SIGNIFICANT ACCUMULATIONS WITH THIS
EVENT.

DRY CONDITIONS WILL RETURN TUE-WED WITH EARLY INDICATIONS OF A
FAIRLY STRONG COLD FRONTAL PASSAGE FOR JUST BEYOND THIS
TIME PERIOD...FOR CHRISTMAS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1013 AM MST WED DEC 17 2014

VFR EXPECTED OVER SE WY TERMINALS THROUGH THE PERIOD.  IFR TO MVFR
CIGS/VSBYS LIKELY TO HOLD ACROSS THE NEB PANHANDLE FOR MOST OF
THE PERIOD DUE TO SNOW COVER AND WEAK UPSLOPE FLOW.

&&

.FIRE WEATHER...
ISSUED AT 328 AM MST WED DEC 17 2014

NO FIRE WEATHER CONCERNS THROUGH FRIDAY.  COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 45 PERCENT AND
WINDS WILL BE WEAK THROUGH THURSDAY.  BY FRIDAY...WEST WINDS WILL
BECOME BREEZY FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

SHORT TERM...ZF
LONG TERM...CAH
AVIATION...RE
FIRE WEATHER...ZF





000
FXUS65 KCYS 171110
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
410 AM MST WED DEC 17 2014

.SHORT TERM...(TODAY AND THROUGH FRIDAY NIGHT)
ISSUED AT 350 AM MST WED DEC 17 2014

SPLIT FLOW PATTERN WILL BE IN PLACE ACROSS THE REGION TODAY. THERE
IS A WEAK SHORTWAVE MOVING TO THE NORTH OF THE CWA AND A MORE
POTENT AND MOISTURE LADEN SHORTWAVE OVER NORTHERN NEW MEXICO. THIS
PUTS US IN THE MIDDLE BETWEEN THE SYSTEMS. THE MODELS CONTINUE TO
INDICATE THAT THE BEST MOISTURE ASSOCIATED WITH THE SOUTHERN WAVE
WILL BE SOUTH INTO COLORADO. THUS...ONLY HAVE SLIGHT CHANCE TO
CHANCE POPS OVER THE SIERRA MADRE AND SNOWY RANGES THROUGH THE
DAY. THE ONLY NOTICEABLE IMPACT OVER MUCH OF THE CWA WILL BE AN
INCREASE IN MID AND HIGH LEVEL CLOUDS. THE EASTERN ZONES WILL BE
DEALING WITH STRATUS THROUGH THE MORNING AS WINDS TO THE EAST OF
THE SFC TROUGH ARE SOUTHERLY OUT THERE. ANOTHER COOL DAY IS IN
STORE AND DROPPED HIGHS A FEW DEGREES OVER THE PANHANDLE WHERE
SNOW COVER IS STILL PRESENT. WINDS WILL ONCE AGAIN BE RATHER WEAK
WITH MINIMAL LLVL GRADIENTS AND FLOW ALOFT.

THERE WILL NOT BE MUCH CHANGE IN THE PATTERN THROUGH THE REMAINDER
OF THE SHORT TERM. THE CAG-CPR GRADIENT...WHICH STAYS BELOW 25
METERS THROUGH THURSDAY NIGHT...WILL INCREASE TO 35-40 METERS BY
FRI MORNING AND AFTN. THUS...WILL BEGIN TO SEE WINDS BECOME BREEZY
OVER MUCH OF SOUTHEAST WY BY FRI AND LOCALLY WINDY IN THE WIND
PRONE SPOTS. TEMPERATURES WILL REMAIN CONSTANT THROUGH
FRI...GENERALLY AT SEASONAL NORMS FOR MID DEC. SLIGHT CHANCE POPS
WILL BE CONFINED TO THE MTNS WEST OF THE LARAMIE RANGE.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 350 AM MST WED DEC 17 2014

THE MAIN HIGHLIGHTS FOR THE WEEKEND AND EARLY NEXT WEEK WILL BE THE
RETURN TO BREEZY TO LOCALLY WINDY CONDITIONS ACROSS SOUTHEAST
WYOMING ALONG WITH A GOOD SHOT OF MOUNTAIN SNOW LATE SUNDAY THROUGH
MONDAY. WEAK NON-DESCRIPT WEST/NORTHWEST FLOW WILL BE IN PLACE ON
SATURDAY. WEAK SHORTWAVE ENERGY WILL BE EMBEDDED WITHIN THE
FLOW...BUT ASIDE FROM LIGHT SNOW SHOWER CHANCES FOR THE SNOWY/SIERRA
MADRES EXPECT LITTLE IF ANY SENSIBLE WEATHER IMPACT. SATURDAY WILL
BE THE LAST RELATIVELY WIND-FREE DAY ACROSS SOUTHEAST WYOMING BEFORE
THE WIND MACHINE GETS CRANKING SUN-TUE.

00Z MODELS HAVE TRENDED FASTER WITH THE TIMING OF THE NOSE OF THE
ANTICYCLONIC JET...NOW PUSHING IT IN DURING THE DAY ON SUNDAY. SO
WILL SEE A STEADY INCREASE IN WIND SPEEDS...FIRST ACROSS THE WIND
PRONE AREAS SATURDAY NIGHT BEFORE SPILLING INTO LOWER ELEVATIONS
SUNDAY AND MONDAY. H7 WIND PROGS CONTINUE TO REACH 50-60 KNOTS
DURING THIS PERIOD WHICH SHOULD BE ENOUGH TO NECESSITATE A WIND
HIGHLIGHT AT LEAST FOR THE WIND PRONE AREAS WITH TIME. AREAS AWAY
FROM THE TYPICALLY WINDY AREAS ARE MORE TRICKY AND TYPICALLY TIED TO
MAGNITUDE OF PBL WHICH CAN BE AFFECTED BY A NUMBER OF THINGS
INCLUDING CLOUD COVER. AT THE VERY LEAST WILL SEE WIDESPREAD BREEZY
CONDITIONS EVEN SPREADING OVER INTO THE WRN NEBRASKA PANHANDLE MON-
TUE. THE GOOD NEWS WITH THE RETURN OF THE WIND WILL BE THAT
TEMPERATURES WILL WARM AROUND 5F AREA WIDE WITH DEEPER LLVL MIXING.
HIGH TEMPERATURES ON MONDAY WILL RETURN TO NR 40 WEST OF THE LARAMIE
RANGE AND MID 40S EAST.

MODELS CLIP THE AREA WITH A SERIES OF SHORTWAVE TROUGHS SUNDAY AND
MONDAY. MOISTURE ADVECTED BY THESE WILL COMBINE WITH FAVORABLE
OROGRAPHIC FLOW TO PRODUCE A GOOD CHANCE FOR ACCUMULATING MOUNTAIN
SNOWS ESPECIALLY LATE SUNDAY THROUGH MONDAY. AMOUNTS WOULD ADD UP IN
A HURRY IN THIS PATTERN AND IF TRENDS CONTINUE WOULD PROBABLY NEED
SOME SORT OF A WINTER HIGHLIGHT THERE IN TIME. AREAS OUTSIDE OF THE
MOUNTAINS MAY SEE SOME PRECIPITATION AS WELL ESPECIALLY SUNDAY NIGHT
AND MONDAY...THOUGH DO NOT SEE SIGNIFICANT ACCUMULATIONS WITH THIS
EVENT.

DRY CONDITIONS WILL RETURN TUE-WED WITH EARLY INDICATIONS OF A
FAIRLY STRONG COLD FRONTAL PASSAGE FOR JUST BEYOND THIS
TIME PERIOD...FOR CHRISTMAS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 350 AM MST WED DEC 17 2014

LOW STRATUS AND PATCHY FOG WILL CONTINUE TO BE THE MAIN AVIATION
HAZARD THIS TAF PERIOD. MVFR TO IFR CIGS/VSBYS ARE POSSIBLE THRU MID-
MORNING...MAINLY OVER THE NEBRASKA TERMINALS. THERE MAY BE A BRIEF
PERIOD OF IMPROVING CONDITIONS AROUND 15-18Z BEFORE MOISTURE
INCREASES AGAIN IN THE AFTERNOON. IFR CIGS COULD REMAIN IN PLACE
OVER KAIA THROUGH WED NIGHT.

&&

.FIRE WEATHER...
ISSUED AT 328 AM MST WED DEC 17 2014

NO FIRE WEATHER CONCERNS THROUGH FRIDAY.  COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 45 PERCENT AND
WINDS WILL BE WEAK THROUGH THURSDAY.  BY FRIDAY...WEST WINDS WILL
BECOME BREEZY FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

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




000
FXUS65 KCYS 171110
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
410 AM MST WED DEC 17 2014

.SHORT TERM...(TODAY AND THROUGH FRIDAY NIGHT)
ISSUED AT 350 AM MST WED DEC 17 2014

SPLIT FLOW PATTERN WILL BE IN PLACE ACROSS THE REGION TODAY. THERE
IS A WEAK SHORTWAVE MOVING TO THE NORTH OF THE CWA AND A MORE
POTENT AND MOISTURE LADEN SHORTWAVE OVER NORTHERN NEW MEXICO. THIS
PUTS US IN THE MIDDLE BETWEEN THE SYSTEMS. THE MODELS CONTINUE TO
INDICATE THAT THE BEST MOISTURE ASSOCIATED WITH THE SOUTHERN WAVE
WILL BE SOUTH INTO COLORADO. THUS...ONLY HAVE SLIGHT CHANCE TO
CHANCE POPS OVER THE SIERRA MADRE AND SNOWY RANGES THROUGH THE
DAY. THE ONLY NOTICEABLE IMPACT OVER MUCH OF THE CWA WILL BE AN
INCREASE IN MID AND HIGH LEVEL CLOUDS. THE EASTERN ZONES WILL BE
DEALING WITH STRATUS THROUGH THE MORNING AS WINDS TO THE EAST OF
THE SFC TROUGH ARE SOUTHERLY OUT THERE. ANOTHER COOL DAY IS IN
STORE AND DROPPED HIGHS A FEW DEGREES OVER THE PANHANDLE WHERE
SNOW COVER IS STILL PRESENT. WINDS WILL ONCE AGAIN BE RATHER WEAK
WITH MINIMAL LLVL GRADIENTS AND FLOW ALOFT.

THERE WILL NOT BE MUCH CHANGE IN THE PATTERN THROUGH THE REMAINDER
OF THE SHORT TERM. THE CAG-CPR GRADIENT...WHICH STAYS BELOW 25
METERS THROUGH THURSDAY NIGHT...WILL INCREASE TO 35-40 METERS BY
FRI MORNING AND AFTN. THUS...WILL BEGIN TO SEE WINDS BECOME BREEZY
OVER MUCH OF SOUTHEAST WY BY FRI AND LOCALLY WINDY IN THE WIND
PRONE SPOTS. TEMPERATURES WILL REMAIN CONSTANT THROUGH
FRI...GENERALLY AT SEASONAL NORMS FOR MID DEC. SLIGHT CHANCE POPS
WILL BE CONFINED TO THE MTNS WEST OF THE LARAMIE RANGE.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 350 AM MST WED DEC 17 2014

THE MAIN HIGHLIGHTS FOR THE WEEKEND AND EARLY NEXT WEEK WILL BE THE
RETURN TO BREEZY TO LOCALLY WINDY CONDITIONS ACROSS SOUTHEAST
WYOMING ALONG WITH A GOOD SHOT OF MOUNTAIN SNOW LATE SUNDAY THROUGH
MONDAY. WEAK NON-DESCRIPT WEST/NORTHWEST FLOW WILL BE IN PLACE ON
SATURDAY. WEAK SHORTWAVE ENERGY WILL BE EMBEDDED WITHIN THE
FLOW...BUT ASIDE FROM LIGHT SNOW SHOWER CHANCES FOR THE SNOWY/SIERRA
MADRES EXPECT LITTLE IF ANY SENSIBLE WEATHER IMPACT. SATURDAY WILL
BE THE LAST RELATIVELY WIND-FREE DAY ACROSS SOUTHEAST WYOMING BEFORE
THE WIND MACHINE GETS CRANKING SUN-TUE.

00Z MODELS HAVE TRENDED FASTER WITH THE TIMING OF THE NOSE OF THE
ANTICYCLONIC JET...NOW PUSHING IT IN DURING THE DAY ON SUNDAY. SO
WILL SEE A STEADY INCREASE IN WIND SPEEDS...FIRST ACROSS THE WIND
PRONE AREAS SATURDAY NIGHT BEFORE SPILLING INTO LOWER ELEVATIONS
SUNDAY AND MONDAY. H7 WIND PROGS CONTINUE TO REACH 50-60 KNOTS
DURING THIS PERIOD WHICH SHOULD BE ENOUGH TO NECESSITATE A WIND
HIGHLIGHT AT LEAST FOR THE WIND PRONE AREAS WITH TIME. AREAS AWAY
FROM THE TYPICALLY WINDY AREAS ARE MORE TRICKY AND TYPICALLY TIED TO
MAGNITUDE OF PBL WHICH CAN BE AFFECTED BY A NUMBER OF THINGS
INCLUDING CLOUD COVER. AT THE VERY LEAST WILL SEE WIDESPREAD BREEZY
CONDITIONS EVEN SPREADING OVER INTO THE WRN NEBRASKA PANHANDLE MON-
TUE. THE GOOD NEWS WITH THE RETURN OF THE WIND WILL BE THAT
TEMPERATURES WILL WARM AROUND 5F AREA WIDE WITH DEEPER LLVL MIXING.
HIGH TEMPERATURES ON MONDAY WILL RETURN TO NR 40 WEST OF THE LARAMIE
RANGE AND MID 40S EAST.

MODELS CLIP THE AREA WITH A SERIES OF SHORTWAVE TROUGHS SUNDAY AND
MONDAY. MOISTURE ADVECTED BY THESE WILL COMBINE WITH FAVORABLE
OROGRAPHIC FLOW TO PRODUCE A GOOD CHANCE FOR ACCUMULATING MOUNTAIN
SNOWS ESPECIALLY LATE SUNDAY THROUGH MONDAY. AMOUNTS WOULD ADD UP IN
A HURRY IN THIS PATTERN AND IF TRENDS CONTINUE WOULD PROBABLY NEED
SOME SORT OF A WINTER HIGHLIGHT THERE IN TIME. AREAS OUTSIDE OF THE
MOUNTAINS MAY SEE SOME PRECIPITATION AS WELL ESPECIALLY SUNDAY NIGHT
AND MONDAY...THOUGH DO NOT SEE SIGNIFICANT ACCUMULATIONS WITH THIS
EVENT.

DRY CONDITIONS WILL RETURN TUE-WED WITH EARLY INDICATIONS OF A
FAIRLY STRONG COLD FRONTAL PASSAGE FOR JUST BEYOND THIS
TIME PERIOD...FOR CHRISTMAS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 350 AM MST WED DEC 17 2014

LOW STRATUS AND PATCHY FOG WILL CONTINUE TO BE THE MAIN AVIATION
HAZARD THIS TAF PERIOD. MVFR TO IFR CIGS/VSBYS ARE POSSIBLE THRU MID-
MORNING...MAINLY OVER THE NEBRASKA TERMINALS. THERE MAY BE A BRIEF
PERIOD OF IMPROVING CONDITIONS AROUND 15-18Z BEFORE MOISTURE
INCREASES AGAIN IN THE AFTERNOON. IFR CIGS COULD REMAIN IN PLACE
OVER KAIA THROUGH WED NIGHT.

&&

.FIRE WEATHER...
ISSUED AT 328 AM MST WED DEC 17 2014

NO FIRE WEATHER CONCERNS THROUGH FRIDAY.  COLD TEMPERATURES
WILL KEEP SNOW COVER ON THE GROUND ACROSS MUCH OF THE REGION.
AFTERNOON HUMIDITY VALUES WILL GENERALLY BE ABOVE 45 PERCENT AND
WINDS WILL BE WEAK THROUGH THURSDAY.  BY FRIDAY...WEST WINDS WILL
BECOME BREEZY FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

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





000
FXUS65 KCYS 170546
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1046 PM MST TUE DEC 16 2014

.UPDATE...
ISSUED AT 813 PM MST TUE DEC 16 2014

LATEST RADAR LOOP SHOWS A BAND OF LIGHT SNOW SHOWERS LIFTING INTO
THE SOUTHERN NE PANHANDLE FROM NORTHEAST CO. THIS APPEARS TO BE
ASSOCIATED WITH A WEAK MIDLVL DISTURBANCE TRAVERSING THE CENTRAL
HIGH PLAINS ATTM. WITH SOME BANDING OWING TO WEAK FRONTOGENESIS
AROUND H7...COULD SEE A DUSTING OF SNOW ALONG AND SOUTH OF THE I80
CORRIDOR IN NE TONIGHT. ADDED A SLIGHT CHANCE OF SNOW THROUGH 06Z
WED. FOG IS STILL A CONCERN FOR THE OVERNIGHT HOURS. LOWEST VSBYS
SO FAR HAVE BEEN ALONG THE PLATTE RIVER WITH MOIST UPVALLEY WINDS
OUT OF THE EAST/SOUTHEAST. THESE AREAS SAW THE MOST SNOW WITH THE
RECENT STORM AS WELL...SO THERE IS PLENTY OF BLYR MOISTURE TO GO
AROUND. THE HRRR STILL SUGGESTS PATCHY FOG WILL LIKELY EXPAND TO
OTHER PARTS OF EAST CENTRAL WY AND THE WESTERN PANHANDLE
OVERNIGHT...EXCEPT ADJACENT TO THE LARAMIE RANGE WHERE THE LLVLS
SHOULD STAY MORE MIXED. LIGHT WEST WINDS AND AMPLE LLVL MOISTURE
COULD RESULT IN PATCHY FOG WEST OF THE LARAMIE RANGE AS WELL.
INCREASED TEMPERATURES A FEW DEGREES OVER THE PANHANDLE WITH LOW
STRATUS MINIMIZING THE POTENTIAL FOR RADIATIONAL COOLING. ONLY
OTHER CHANGES WERE TO ADJUST SKY TRENDS AND THE TIMING/INTENSITY
OF FOG.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 243 PM MST TUE DEC 16 2014

TONIGHT...MOST WIDESPREAD CHALLENGE WILL BE FOG
DEVELOPMENT...INCLUDING AREAL COVERAGE AND VISIBILITIES. WHERE FOG
WAS SLOWEST TO ERODE...FROM TORRINGTON...TO SCOTTSBLUFF AND TO
ALLIANCE...INCLUDING OVER THE SNOWFIELD...3 PM TEMPERATURE AND
DEWPOINT SPREADS ARE ONLY 2 TO 5 DEGREES WITH CLEARING MID LEVEL
SKIES NOTED ON VISIBLE SATELLITE IMAGERY...THUS EXPECT FOG TO
DEVELOP RATHER QUICKLY AND SPREAD OVER AFOREMENTIONED LOCALES IN
THE LATE AFTERNOON AND EARLY EVENING HOURS.

LOW LEVELS AND BOUNDARY LAYER SATURATE UP DECENTLY
OVERNIGHT...ESPECIALLY OVER OUR WESTERN COUNTIES OF CARBON AND
ALBANY...AND MID AFTERNOON TEMPERATURE DEWPOINT SPREADS ARE ONLY
AROUND 7 DEGREES AT RAWLINS AND LARAMIE...ALONG WITH MID LEVEL
CLEARING PROGGED...THUS EXPECT RATHER EXTENSIVE FOG TO DEVELOP LATE
THIS EVENING AND OVERNIGHT ACROSS OUR WESTERN COUNTIES.

NEGATIVELY TILTED SHORTWAVE TROUGH ALOFT MOVES FROM WESTERN WYOMING
THIS AFTERNOON...TO NORTHWEST WYOMING BY MIDNIGHT AND TO CENTRAL
MONTANA BY DAYBREAK...BASED ON SATELLITE AND RADAR TRENDS...EXPECT
INCREASING AREAL COVERAGE OF SNOW SHOWERS THIS EVENING ACROSS OUR
WYOMING COUNTIES...ESPECIALLY OVER AND NEAR THE SNOWY AND SIERRA
MADRE RANGES...WITH A SLOW CESSATION AND DECREASE IN AREAL SNOW
COVERAGE LATE THIS EVENING AND OVERNIGHT. MAY EVEN SEE A FEW
FLAKES ALONG AND EAST OF INTERSTATE 25...THOUGH COVERAGE LOOKS
QUITE MINIMAL.

WEDNESDAY...SPLIT TROUGHS ALOFT MOVE ACROSS OUR REGION WITH THE
BULK OF SNOW AND DEEPER MOISTURE LOCATED OVER COLORADO...THOUGH
OUR SNOWY AND SIERRA MADRE RANGES WILL SEE SCATTERED OROGRAPHIC
SNOW SHOWERS...MOSTLY DRY ELSEWHERE.

WEDNESDAY NIGHT...NORTHERN STREAM SHORTWAVE TROUGH ALOFT MOVES OVER
THE WESTERN DAKOTAS...WITH THE SOUTHERN STREAM SHORTWAVE TROUGH
ALOFT MOVING OVER WESTERN KANSAS...THUS MINIMAL COVERAGE OF SNOW
SHOWERS OVER OUR COUNTIES...MAINLY OVER THE SNOWY AND SIERRA MADRE
RANGES...DRY ELSEWHERE.

THURSDAY...PSEUDO CYCLONIC FLOW ALOFT CONTINUES OVER OUR COUNTIES
WITH ONE SHORTWAVE ALOFT OVER THE FOUR CORNERS WITH MOST OF THAT
SHORTWAVE TROUGH SNOW OVER WESTERN COLORADO...THOUGH WILL SEE SOME
OROGRAPHIC SNOW SHOWERS OVER OUR SNOWY AND SIERRA MADRE RANGES...
DRY ELSEWHERE.

THURSDAY NIGHT...FAST MOVING...MOISTURE STARVED SHORTWAVE TROUGH
ALOFT MOVES ACROSS OUR COUNTIES...THOUGH WITH MINIMAL LOW AND MID
LEVEL MOISTURE...ONLY SOME ISOLATED MOUNTAIN SNOW SHOWERS ON TAP.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 243 PM MST TUE DEC 16 2014

SHORTWAVE TROUGH WILL MOVE OVERHEAD ON FRIDAY UNDER WEAK NORTHWEST
FLOW. MODELS KEEP THE HIGHEST LLVL MOISTURE OVER THE MOUNTAINS THRU
THE DAY WHICH IS REASONABLE IN THIS FLOW PATTERN...SO KEPT SNOW
CHANCES CONFINED TO THE SNOWY AND SIERRA MADRES MOUNTAINS. ANOTHER
WEAK SHORTWAVE TROUGH WILL MOVE THROUGH ON SATURDAY/SATURDAY NIGHT
WITH A SLIGHTLY MORE NORTHERLY TRACK...SO COULD SEE LIGHT SNOW
SHOWERS RETURNING TO THE MOUNTAINS INCLUDING THE NORTHERN LARAMIE
RANGE THROUGH THIS TIME. WINDS ALOFT WILL BEGIN TO INCREASE SUNDAY
AND MONDAY AS A STRONG EASTERN PAC HIGH BUILDS IN FROM THE WEST. THE
STORM TRACK WILL THUS SHIFT OVER THE NORTHERN ROCKIES AND HIGH
PLAINS THROUGH THE EARLY PART OF THE WEEK...WITH WINDY CONDITIONS
AND INCREASING COVERAGE OF SNOW SHOWERS EXPECTED. THE NOSE OF A 150+
KT JET WILL MOVE OVERHEAD MONDAY...WITH A RATHER VIGOROUS VORT MAX
MOVING FROM THE NORTHERN ROCKIES INTO THE CENTRAL PLAINS IN THE LFQ
REGION OF THE JET. STILL LOOKS FAVORABLE FOR MORE WIDESPREAD SNOW
SHOWERS OVER THE CWA ON MONDAY...ESPECIALLY OVER THE MOUNTAINS AND
NORTHERN PLAINS FROM DOUGLAS TO ALLIANCE IN BETTER PROXIMITY TO THE
JET DIFLUENCE AND LIFT FROM THE VORT MAX. THE LLVL GRADIENT WILL
INCREASE IN ADVANCE OF THE WAVE AS THE LEESIDE TROUGH DEEPENS AS
WELL...SO SHOULD ALSO SEE WINDS BECOME MODERATE TO STRONG LATE
SUNDAY THROUGH MONDAY. THE ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE EASTERN PLAINS SOMETIME LATE MONDAY...AND SHOULD STALL HERE
THROUGH TUESDAY. WINDY CONDITIONS WITH CHANCES FOR LIGHT SNOW WILL
CONTINUE OVER THE MOUNTAINS WITH RAIN/SNOW MIX OVER THE PLAINS AS A
RESULT. TEMPS THROUGH THE PERIOD WILL REMAIN AROUND NORMAL FOR THIS
TIME OF YEAR...WITH A SLIGHT BUMP UPWARDS AS DOWNSLOPE WINDS KICK IN
FOR MONDAY AND TUESDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1040 PM MST TUE DEC 16 2014

LOW STRATUS AND PATCHY FOG WILL CONTINUE TO BE THE MAIN AVIATION
HAZARD THIS TAF PERIOD. MVFR TO IFR CIGS/VSBYS ARE POSSIBLE THRU
THE NIGHT...MAINLY OVER THE NEBRASKA TERMINALS. THERE MAY BE A
BRIEF PERIOD OF IMPROVING CONDITIONS AROUND 15-18Z BEFORE MOISTURE
INCREASES AGAIN IN THE AFTERNOON. IFR CIGS COULD REMAIN IN PLACE
OVER KAIA THROUGH WED NIGHT.

&&

.FIRE WEATHER...
ISSUED AT 243 PM MST TUE DEC 16 2014

MINIMAL ISSUES DUE TO PROJECTED HUMIDITIES AND WINDS.

&&

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

$$

UPDATE...CLH
SHORT TERM...RUBIN
LONG TERM...RJM
AVIATION...CLH
FIRE WEATHER...RUBIN




000
FXUS65 KCYS 170546
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1046 PM MST TUE DEC 16 2014

.UPDATE...
ISSUED AT 813 PM MST TUE DEC 16 2014

LATEST RADAR LOOP SHOWS A BAND OF LIGHT SNOW SHOWERS LIFTING INTO
THE SOUTHERN NE PANHANDLE FROM NORTHEAST CO. THIS APPEARS TO BE
ASSOCIATED WITH A WEAK MIDLVL DISTURBANCE TRAVERSING THE CENTRAL
HIGH PLAINS ATTM. WITH SOME BANDING OWING TO WEAK FRONTOGENESIS
AROUND H7...COULD SEE A DUSTING OF SNOW ALONG AND SOUTH OF THE I80
CORRIDOR IN NE TONIGHT. ADDED A SLIGHT CHANCE OF SNOW THROUGH 06Z
WED. FOG IS STILL A CONCERN FOR THE OVERNIGHT HOURS. LOWEST VSBYS
SO FAR HAVE BEEN ALONG THE PLATTE RIVER WITH MOIST UPVALLEY WINDS
OUT OF THE EAST/SOUTHEAST. THESE AREAS SAW THE MOST SNOW WITH THE
RECENT STORM AS WELL...SO THERE IS PLENTY OF BLYR MOISTURE TO GO
AROUND. THE HRRR STILL SUGGESTS PATCHY FOG WILL LIKELY EXPAND TO
OTHER PARTS OF EAST CENTRAL WY AND THE WESTERN PANHANDLE
OVERNIGHT...EXCEPT ADJACENT TO THE LARAMIE RANGE WHERE THE LLVLS
SHOULD STAY MORE MIXED. LIGHT WEST WINDS AND AMPLE LLVL MOISTURE
COULD RESULT IN PATCHY FOG WEST OF THE LARAMIE RANGE AS WELL.
INCREASED TEMPERATURES A FEW DEGREES OVER THE PANHANDLE WITH LOW
STRATUS MINIMIZING THE POTENTIAL FOR RADIATIONAL COOLING. ONLY
OTHER CHANGES WERE TO ADJUST SKY TRENDS AND THE TIMING/INTENSITY
OF FOG.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 243 PM MST TUE DEC 16 2014

TONIGHT...MOST WIDESPREAD CHALLENGE WILL BE FOG
DEVELOPMENT...INCLUDING AREAL COVERAGE AND VISIBILITIES. WHERE FOG
WAS SLOWEST TO ERODE...FROM TORRINGTON...TO SCOTTSBLUFF AND TO
ALLIANCE...INCLUDING OVER THE SNOWFIELD...3 PM TEMPERATURE AND
DEWPOINT SPREADS ARE ONLY 2 TO 5 DEGREES WITH CLEARING MID LEVEL
SKIES NOTED ON VISIBLE SATELLITE IMAGERY...THUS EXPECT FOG TO
DEVELOP RATHER QUICKLY AND SPREAD OVER AFOREMENTIONED LOCALES IN
THE LATE AFTERNOON AND EARLY EVENING HOURS.

LOW LEVELS AND BOUNDARY LAYER SATURATE UP DECENTLY
OVERNIGHT...ESPECIALLY OVER OUR WESTERN COUNTIES OF CARBON AND
ALBANY...AND MID AFTERNOON TEMPERATURE DEWPOINT SPREADS ARE ONLY
AROUND 7 DEGREES AT RAWLINS AND LARAMIE...ALONG WITH MID LEVEL
CLEARING PROGGED...THUS EXPECT RATHER EXTENSIVE FOG TO DEVELOP LATE
THIS EVENING AND OVERNIGHT ACROSS OUR WESTERN COUNTIES.

NEGATIVELY TILTED SHORTWAVE TROUGH ALOFT MOVES FROM WESTERN WYOMING
THIS AFTERNOON...TO NORTHWEST WYOMING BY MIDNIGHT AND TO CENTRAL
MONTANA BY DAYBREAK...BASED ON SATELLITE AND RADAR TRENDS...EXPECT
INCREASING AREAL COVERAGE OF SNOW SHOWERS THIS EVENING ACROSS OUR
WYOMING COUNTIES...ESPECIALLY OVER AND NEAR THE SNOWY AND SIERRA
MADRE RANGES...WITH A SLOW CESSATION AND DECREASE IN AREAL SNOW
COVERAGE LATE THIS EVENING AND OVERNIGHT. MAY EVEN SEE A FEW
FLAKES ALONG AND EAST OF INTERSTATE 25...THOUGH COVERAGE LOOKS
QUITE MINIMAL.

WEDNESDAY...SPLIT TROUGHS ALOFT MOVE ACROSS OUR REGION WITH THE
BULK OF SNOW AND DEEPER MOISTURE LOCATED OVER COLORADO...THOUGH
OUR SNOWY AND SIERRA MADRE RANGES WILL SEE SCATTERED OROGRAPHIC
SNOW SHOWERS...MOSTLY DRY ELSEWHERE.

WEDNESDAY NIGHT...NORTHERN STREAM SHORTWAVE TROUGH ALOFT MOVES OVER
THE WESTERN DAKOTAS...WITH THE SOUTHERN STREAM SHORTWAVE TROUGH
ALOFT MOVING OVER WESTERN KANSAS...THUS MINIMAL COVERAGE OF SNOW
SHOWERS OVER OUR COUNTIES...MAINLY OVER THE SNOWY AND SIERRA MADRE
RANGES...DRY ELSEWHERE.

THURSDAY...PSEUDO CYCLONIC FLOW ALOFT CONTINUES OVER OUR COUNTIES
WITH ONE SHORTWAVE ALOFT OVER THE FOUR CORNERS WITH MOST OF THAT
SHORTWAVE TROUGH SNOW OVER WESTERN COLORADO...THOUGH WILL SEE SOME
OROGRAPHIC SNOW SHOWERS OVER OUR SNOWY AND SIERRA MADRE RANGES...
DRY ELSEWHERE.

THURSDAY NIGHT...FAST MOVING...MOISTURE STARVED SHORTWAVE TROUGH
ALOFT MOVES ACROSS OUR COUNTIES...THOUGH WITH MINIMAL LOW AND MID
LEVEL MOISTURE...ONLY SOME ISOLATED MOUNTAIN SNOW SHOWERS ON TAP.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 243 PM MST TUE DEC 16 2014

SHORTWAVE TROUGH WILL MOVE OVERHEAD ON FRIDAY UNDER WEAK NORTHWEST
FLOW. MODELS KEEP THE HIGHEST LLVL MOISTURE OVER THE MOUNTAINS THRU
THE DAY WHICH IS REASONABLE IN THIS FLOW PATTERN...SO KEPT SNOW
CHANCES CONFINED TO THE SNOWY AND SIERRA MADRES MOUNTAINS. ANOTHER
WEAK SHORTWAVE TROUGH WILL MOVE THROUGH ON SATURDAY/SATURDAY NIGHT
WITH A SLIGHTLY MORE NORTHERLY TRACK...SO COULD SEE LIGHT SNOW
SHOWERS RETURNING TO THE MOUNTAINS INCLUDING THE NORTHERN LARAMIE
RANGE THROUGH THIS TIME. WINDS ALOFT WILL BEGIN TO INCREASE SUNDAY
AND MONDAY AS A STRONG EASTERN PAC HIGH BUILDS IN FROM THE WEST. THE
STORM TRACK WILL THUS SHIFT OVER THE NORTHERN ROCKIES AND HIGH
PLAINS THROUGH THE EARLY PART OF THE WEEK...WITH WINDY CONDITIONS
AND INCREASING COVERAGE OF SNOW SHOWERS EXPECTED. THE NOSE OF A 150+
KT JET WILL MOVE OVERHEAD MONDAY...WITH A RATHER VIGOROUS VORT MAX
MOVING FROM THE NORTHERN ROCKIES INTO THE CENTRAL PLAINS IN THE LFQ
REGION OF THE JET. STILL LOOKS FAVORABLE FOR MORE WIDESPREAD SNOW
SHOWERS OVER THE CWA ON MONDAY...ESPECIALLY OVER THE MOUNTAINS AND
NORTHERN PLAINS FROM DOUGLAS TO ALLIANCE IN BETTER PROXIMITY TO THE
JET DIFLUENCE AND LIFT FROM THE VORT MAX. THE LLVL GRADIENT WILL
INCREASE IN ADVANCE OF THE WAVE AS THE LEESIDE TROUGH DEEPENS AS
WELL...SO SHOULD ALSO SEE WINDS BECOME MODERATE TO STRONG LATE
SUNDAY THROUGH MONDAY. THE ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE EASTERN PLAINS SOMETIME LATE MONDAY...AND SHOULD STALL HERE
THROUGH TUESDAY. WINDY CONDITIONS WITH CHANCES FOR LIGHT SNOW WILL
CONTINUE OVER THE MOUNTAINS WITH RAIN/SNOW MIX OVER THE PLAINS AS A
RESULT. TEMPS THROUGH THE PERIOD WILL REMAIN AROUND NORMAL FOR THIS
TIME OF YEAR...WITH A SLIGHT BUMP UPWARDS AS DOWNSLOPE WINDS KICK IN
FOR MONDAY AND TUESDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1040 PM MST TUE DEC 16 2014

LOW STRATUS AND PATCHY FOG WILL CONTINUE TO BE THE MAIN AVIATION
HAZARD THIS TAF PERIOD. MVFR TO IFR CIGS/VSBYS ARE POSSIBLE THRU
THE NIGHT...MAINLY OVER THE NEBRASKA TERMINALS. THERE MAY BE A
BRIEF PERIOD OF IMPROVING CONDITIONS AROUND 15-18Z BEFORE MOISTURE
INCREASES AGAIN IN THE AFTERNOON. IFR CIGS COULD REMAIN IN PLACE
OVER KAIA THROUGH WED NIGHT.

&&

.FIRE WEATHER...
ISSUED AT 243 PM MST TUE DEC 16 2014

MINIMAL ISSUES DUE TO PROJECTED HUMIDITIES AND WINDS.

&&

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

$$

UPDATE...CLH
SHORT TERM...RUBIN
LONG TERM...RJM
AVIATION...CLH
FIRE WEATHER...RUBIN





000
FXUS65 KCYS 170324
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
824 PM MST TUE DEC 16 2014

.UPDATE...
ISSUED AT 813 PM MST TUE DEC 16 2014

LATEST RADAR LOOP SHOWS A BAND OF LIGHT SNOW SHOWERS LIFTING INTO
THE SOUTHERN NE PANHANDLE FROM NORTHEAST CO. THIS APPEARS TO BE
ASSOCIATED WITH A WEAK MIDLVL DISTURBANCE TRAVERSING THE CENTRAL
HIGH PLAINS ATTM. WITH SOME BANDING OWING TO WEAK FRONTOGENESIS
AROUND H7...COULD SEE A DUSTING OF SNOW ALONG AND SOUTH OF THE I80
CORRIDOR IN NE TONIGHT. ADDED A SLIGHT CHANCE OF SNOW THROUGH 06Z
WED. FOG IS STILL A CONCERN FOR THE OVERNIGHT HOURS. LOWEST VSBYS
SO FAR HAVE BEEN ALONG THE PLATTE RIVER WITH MOIST UPVALLEY WINDS
OUT OF THE EAST/SOUTHEAST. THESE AREAS SAW THE MOST SNOW WITH THE
RECENT STORM AS WELL...SO THERE IS PLENTY OF BLYR MOISTURE TO GO
AROUND. THE HRRR STILL SUGGESTS PATCHY FOG WILL LIKELY EXPAND TO
OTHER PARTS OF EAST CENTRAL WY AND THE WESTERN PANHANDLE
OVERNIGHT...EXCEPT ADJACENT TO THE LARAMIE RANGE WHERE THE LLVLS
SHOULD STAY MORE MIXED. LIGHT WEST WINDS AND AMPLE LLVL MOISTURE
COULD RESULT IN PATCHY FOG WEST OF THE LARAMIE RANGE AS WELL.
INCREASED TEMPERATURES A FEW DEGREES OVER THE PANHANDLE WITH LOW
STRATUS MINIMIZING THE POTENTIAL FOR RADIATIONAL COOLING. ONLY
OTHER CHANGES WERE TO ADJUST SKY TRENDS AND THE TIMING/INTENSITY
OF FOG.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 243 PM MST TUE DEC 16 2014

TONIGHT...MOST WIDESPREAD CHALLENGE WILL BE FOG
DEVELOPMENT...INCLUDING AREAL COVERAGE AND VISIBILITIES. WHERE FOG
WAS SLOWEST TO ERODE...FROM TORRINGTON...TO SCOTTSBLUFF AND TO
ALLIANCE...INCLUDING OVER THE SNOWFIELD...3 PM TEMPERATURE AND
DEWPOINT SPREADS ARE ONLY 2 TO 5 DEGREES WITH CLEARING MID LEVEL
SKIES NOTED ON VISIBLE SATELLITE IMAGERY...THUS EXPECT FOG TO
DEVELOP RATHER QUICKLY AND SPREAD OVER AFOREMENTIONED LOCALES IN
THE LATE AFTERNOON AND EARLY EVENING HOURS.

LOW LEVELS AND BOUNDARY LAYER SATURATE UP DECENTLY
OVERNIGHT...ESPECIALLY OVER OUR WESTERN COUNTIES OF CARBON AND
ALBANY...AND MID AFTERNOON TEMPERATURE DEWPOINT SPREADS ARE ONLY
AROUND 7 DEGREES AT RAWLINS AND LARAMIE...ALONG WITH MID LEVEL
CLEARING PROGGED...THUS EXPECT RATHER EXTENSIVE FOG TO DEVELOP LATE
THIS EVENING AND OVERNIGHT ACROSS OUR WESTERN COUNTIES.

NEGATIVELY TILTED SHORTWAVE TROUGH ALOFT MOVES FROM WESTERN WYOMING
THIS AFTERNOON...TO NORTHWEST WYOMING BY MIDNIGHT AND TO CENTRAL
MONTANA BY DAYBREAK...BASED ON SATELLITE AND RADAR TRENDS...EXPECT
INCREASING AREAL COVERAGE OF SNOW SHOWERS THIS EVENING ACROSS OUR
WYOMING COUNTIES...ESPECIALLY OVER AND NEAR THE SNOWY AND SIERRA
MADRE RANGES...WITH A SLOW CESSATION AND DECREASE IN AREAL SNOW
COVERAGE LATE THIS EVENING AND OVERNIGHT. MAY EVEN SEE A FEW
FLAKES ALONG AND EAST OF INTERSTATE 25...THOUGH COVERAGE LOOKS
QUITE MINIMAL.

WEDNESDAY...SPLIT TROUGHS ALOFT MOVE ACROSS OUR REGION WITH THE
BULK OF SNOW AND DEEPER MOISTURE LOCATED OVER COLORADO...THOUGH
OUR SNOWY AND SIERRA MADRE RANGES WILL SEE SCATTERED OROGRAPHIC
SNOW SHOWERS...MOSTLY DRY ELSEWHERE.

WEDNESDAY NIGHT...NORTHERN STREAM SHORTWAVE TROUGH ALOFT MOVES OVER
THE WESTERN DAKOTAS...WITH THE SOUTHERN STREAM SHORTWAVE TROUGH
ALOFT MOVING OVER WESTERN KANSAS...THUS MINIMAL COVERAGE OF SNOW
SHOWERS OVER OUR COUNTIES...MAINLY OVER THE SNOWY AND SIERRA MADRE
RANGES...DRY ELSEWHERE.

THURSDAY...PSEUDO CYCLONIC FLOW ALOFT CONTINUES OVER OUR COUNTIES
WITH ONE SHORTWAVE ALOFT OVER THE FOUR CORNERS WITH MOST OF THAT
SHORTWAVE TROUGH SNOW OVER WESTERN COLORADO...THOUGH WILL SEE SOME
OROGRAPHIC SNOW SHOWERS OVER OUR SNOWY AND SIERRA MADRE RANGES...
DRY ELSEWHERE.

THURSDAY NIGHT...FAST MOVING...MOISTURE STARVED SHORTWAVE TROUGH
ALOFT MOVES ACROSS OUR COUNTIES...THOUGH WITH MINIMAL LOW AND MID
LEVEL MOISTURE...ONLY SOME ISOLATED MOUNTAIN SNOW SHOWERS ON TAP.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 243 PM MST TUE DEC 16 2014

SHORTWAVE TROUGH WILL MOVE OVERHEAD ON FRIDAY UNDER WEAK NORTHWEST
FLOW. MODELS KEEP THE HIGHEST LLVL MOISTURE OVER THE MOUNTAINS THRU
THE DAY WHICH IS REASONABLE IN THIS FLOW PATTERN...SO KEPT SNOW
CHANCES CONFINED TO THE SNOWY AND SIERRA MADRES MOUNTAINS. ANOTHER
WEAK SHORTWAVE TROUGH WILL MOVE THROUGH ON SATURDAY/SATURDAY NIGHT
WITH A SLIGHTLY MORE NORTHERLY TRACK...SO COULD SEE LIGHT SNOW
SHOWERS RETURNING TO THE MOUNTAINS INCLUDING THE NORTHERN LARAMIE
RANGE THROUGH THIS TIME. WINDS ALOFT WILL BEGIN TO INCREASE SUNDAY
AND MONDAY AS A STRONG EASTERN PAC HIGH BUILDS IN FROM THE WEST. THE
STORM TRACK WILL THUS SHIFT OVER THE NORTHERN ROCKIES AND HIGH
PLAINS THROUGH THE EARLY PART OF THE WEEK...WITH WINDY CONDITIONS
AND INCREASING COVERAGE OF SNOW SHOWERS EXPECTED. THE NOSE OF A 150+
KT JET WILL MOVE OVERHEAD MONDAY...WITH A RATHER VIGOROUS VORT MAX
MOVING FROM THE NORTHERN ROCKIES INTO THE CENTRAL PLAINS IN THE LFQ
REGION OF THE JET. STILL LOOKS FAVORABLE FOR MORE WIDESPREAD SNOW
SHOWERS OVER THE CWA ON MONDAY...ESPECIALLY OVER THE MOUNTAINS AND
NORTHERN PLAINS FROM DOUGLAS TO ALLIANCE IN BETTER PROXIMITY TO THE
JET DIFLUENCE AND LIFT FROM THE VORT MAX. THE LLVL GRADIENT WILL
INCREASE IN ADVANCE OF THE WAVE AS THE LEESIDE TROUGH DEEPENS AS
WELL...SO SHOULD ALSO SEE WINDS BECOME MODERATE TO STRONG LATE
SUNDAY THROUGH MONDAY. THE ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE EASTERN PLAINS SOMETIME LATE MONDAY...AND SHOULD STALL HERE
THROUGH TUESDAY. WINDY CONDITIONS WITH CHANCES FOR LIGHT SNOW WILL
CONTINUE OVER THE MOUNTAINS WITH RAIN/SNOW MIX OVER THE PLAINS AS A
RESULT. TEMPS THROUGH THE PERIOD WILL REMAIN AROUND NORMAL FOR THIS
TIME OF YEAR...WITH A SLIGHT BUMP UPWARDS AS DOWNSLOPE WINDS KICK IN
FOR MONDAY AND TUESDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 501 PM MST TUE DEC 16 2014

FOG WILL BE THE MAIN AVIATION CONCERN FOR MOST TERMINALS ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. LINGERING LIGHT SNOW
SHOWERS SHOULD HAVE LITTLE IMPACT. EXPECT IFR/LIFR CIGS AND VSBYS
TO DEVELOP BETWEEN 03Z AND 06Z AND PERSIST THROUGH THE NIGHT. THE
MOST LIKELY AREA TO SEE LOCALLY DENSE FOG WITH VSBYS LESS THAN ONE
QUARTER OF A MILE WILL BE THE PLATTE RIVER VALLEY WITH LIGHT
UPVALLEY WINDS...INCLUDING BFF. THE PANHANDLE SITES COULD SEE IFR
CONDITIONS WELL INTO THE AFTERNOON ON WED.


&&

.FIRE WEATHER...
ISSUED AT 243 PM MST TUE DEC 16 2014

MINIMAL ISSUES DUE TO PROJECTED HUMIDITIES AND WINDS.

&&

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

$$

UPDATE...CLH
SHORT TERM...RUBIN
LONG TERM...RJM
AVIATION...CLH
FIRE WEATHER...RUBIN




000
FXUS65 KCYS 170006
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
506 PM MST TUE DEC 16 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 243 PM MST TUE DEC 16 2014

TONIGHT...MOST WIDESPREAD CHALLENGE WILL BE FOG
DEVELOPMENT...INCLUDING AREAL COVERAGE AND VISIBILITIES. WHERE FOG
WAS SLOWEST TO ERODE...FROM TORRINGTON...TO SCOTTSBLUFF AND TO
ALLIANCE...INCLUDING OVER THE SNOWFIELD...3 PM TEMPERATURE AND
DEWPOINT SPREADS ARE ONLY 2 TO 5 DEGREES WITH CLEARING MID LEVEL
SKIES NOTED ON VISIBLE SATELLITE IMAGERY...THUS EXPECT FOG TO
DEVELOP RATHER QUICKLY AND SPREAD OVER AFOREMENTIONED LOCALES IN
THE LATE AFTERNOON AND EARLY EVENING HOURS.

LOW LEVELS AND BOUNDARY LAYER SATURATE UP DECENTLY
OVERNIGHT...ESPECIALLY OVER OUR WESTERN COUNTIES OF CARBON AND
ALBANY...AND MID AFTERNOON TEMPERATURE DEWPOINT SPREADS ARE ONLY
AROUND 7 DEGREES AT RAWLINS AND LARAMIE...ALONG WITH MID LEVEL
CLEARING PROGGED...THUS EXPECT RATHER EXTENSIVE FOG TO DEVELOP LATE
THIS EVENING AND OVERNIGHT ACROSS OUR WESTERN COUNTIES.

NEGATIVELY TILTED SHORTWAVE TROUGH ALOFT MOVES FROM WESTERN WYOMING
THIS AFTERNOON...TO NORTHWEST WYOMING BY MIDNIGHT AND TO CENTRAL
MONTANA BY DAYBREAK...BASED ON SATELLITE AND RADAR TRENDS...EXPECT
INCREASING AREAL COVERAGE OF SNOW SHOWERS THIS EVENING ACROSS OUR
WYOMING COUNTIES...ESPECIALLY OVER AND NEAR THE SNOWY AND SIERRA
MADRE RANGES...WITH A SLOW CESSATION AND DECREASE IN AREAL SNOW
COVERAGE LATE THIS EVENING AND OVERNIGHT. MAY EVEN SEE A FEW
FLAKES ALONG AND EAST OF INTERSTATE 25...THOUGH COVERAGE LOOKS
QUITE MINIMAL.

WEDNESDAY...SPLIT TROUGHS ALOFT MOVE ACROSS OUR REGION WITH THE
BULK OF SNOW AND DEEPER MOISTURE LOCATED OVER COLORADO...THOUGH
OUR SNOWY AND SIERRA MADRE RANGES WILL SEE SCATTERED OROGRAPHIC
SNOW SHOWERS...MOSTLY DRY ELSEWHERE.

WEDNESDAY NIGHT...NORTHERN STREAM SHORTWAVE TROUGH ALOFT MOVES OVER
THE WESTERN DAKOTAS...WITH THE SOUTHERN STREAM SHORTWAVE TROUGH
ALOFT MOVING OVER WESTERN KANSAS...THUS MINIMAL COVERAGE OF SNOW
SHOWERS OVER OUR COUNTIES...MAINLY OVER THE SNOWY AND SIERRA MADRE
RANGES...DRY ELSEWHERE.

THURSDAY...PSEUDO CYCLONIC FLOW ALOFT CONTINUES OVER OUR COUNTIES
WITH ONE SHORTWAVE ALOFT OVER THE FOUR CORNERS WITH MOST OF THAT
SHORTWAVE TROUGH SNOW OVER WESTERN COLORADO...THOUGH WILL SEE SOME
OROGRAPHIC SNOW SHOWERS OVER OUR SNOWY AND SIERRA MADRE RANGES...
DRY ELSEWHERE.

THURSDAY NIGHT...FAST MOVING...MOISTURE STARVED SHORTWAVE TROUGH
ALOFT MOVES ACROSS OUR COUNTIES...THOUGH WITH MINIMAL LOW AND MID
LEVEL MOISTURE...ONLY SOME ISOLATED MOUNTAIN SNOW SHOWERS ON TAP.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 243 PM MST TUE DEC 16 2014

SHORTWAVE TROUGH WILL MOVE OVERHEAD ON FRIDAY UNDER WEAK NORTHWEST
FLOW. MODELS KEEP THE HIGHEST LLVL MOISTURE OVER THE MOUNTAINS THRU
THE DAY WHICH IS REASONABLE IN THIS FLOW PATTERN...SO KEPT SNOW
CHANCES CONFINED TO THE SNOWY AND SIERRA MADRES MOUNTAINS. ANOTHER
WEAK SHORTWAVE TROUGH WILL MOVE THROUGH ON SATURDAY/SATURDAY NIGHT
WITH A SLIGHTLY MORE NORTHERLY TRACK...SO COULD SEE LIGHT SNOW
SHOWERS RETURNING TO THE MOUNTAINS INCLUDING THE NORTHERN LARAMIE
RANGE THROUGH THIS TIME. WINDS ALOFT WILL BEGIN TO INCREASE SUNDAY
AND MONDAY AS A STRONG EASTERN PAC HIGH BUILDS IN FROM THE WEST. THE
STORM TRACK WILL THUS SHIFT OVER THE NORTHERN ROCKIES AND HIGH
PLAINS THROUGH THE EARLY PART OF THE WEEK...WITH WINDY CONDITIONS
AND INCREASING COVERAGE OF SNOW SHOWERS EXPECTED. THE NOSE OF A 150+
KT JET WILL MOVE OVERHEAD MONDAY...WITH A RATHER VIGOROUS VORT MAX
MOVING FROM THE NORTHERN ROCKIES INTO THE CENTRAL PLAINS IN THE LFQ
REGION OF THE JET. STILL LOOKS FAVORABLE FOR MORE WIDESPREAD SNOW
SHOWERS OVER THE CWA ON MONDAY...ESPECIALLY OVER THE MOUNTAINS AND
NORTHERN PLAINS FROM DOUGLAS TO ALLIANCE IN BETTER PROXIMITY TO THE
JET DIFLUENCE AND LIFT FROM THE VORT MAX. THE LLVL GRADIENT WILL
INCREASE IN ADVANCE OF THE WAVE AS THE LEESIDE TROUGH DEEPENS AS
WELL...SO SHOULD ALSO SEE WINDS BECOME MODERATE TO STRONG LATE
SUNDAY THROUGH MONDAY. THE ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE EASTERN PLAINS SOMETIME LATE MONDAY...AND SHOULD STALL HERE
THROUGH TUESDAY. WINDY CONDITIONS WITH CHANCES FOR LIGHT SNOW WILL
CONTINUE OVER THE MOUNTAINS WITH RAIN/SNOW MIX OVER THE PLAINS AS A
RESULT. TEMPS THROUGH THE PERIOD WILL REMAIN AROUND NORMAL FOR THIS
TIME OF YEAR...WITH A SLIGHT BUMP UPWARDS AS DOWNSLOPE WINDS KICK IN
FOR MONDAY AND TUESDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 501 PM MST TUE DEC 16 2014

FOG WILL BE THE MAIN AVIATION CONCERN FOR MOST TERMINALS ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. LINGERING LIGHT SNOW
SHOWERS SHOULD HAVE LITTLE IMPACT. EXPECT IFR/LIFR CIGS AND VSBYS
TO DEVELOP BETWEEN 03Z AND 06Z AND PERSIST THROUGH THE NIGHT. THE
MOST LIKELY AREA TO SEE LOCALLY DENSE FOG WITH VSBYS LESS THAN ONE
QUARTER OF A MILE WILL BE THE PLATTE RIVER VALLEY WITH LIGHT
UPVALLEY WINDS...INCLUDING BFF. THE PANHANDLE SITES COULD SEE IFR
CONDITIONS WELL INTO THE AFTERNOON ON WED.

&&

.FIRE WEATHER...
ISSUED AT 243 PM MST TUE DEC 16 2014

MINIMAL ISSUES DUE TO PROJECTED HUMIDITIES AND WINDS.

&&

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

$$

SHORT TERM...RUBIN
LONG TERM...RJM
AVIATION...CLH
FIRE WEATHER...RUBIN




000
FXUS65 KCYS 170006
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
506 PM MST TUE DEC 16 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 243 PM MST TUE DEC 16 2014

TONIGHT...MOST WIDESPREAD CHALLENGE WILL BE FOG
DEVELOPMENT...INCLUDING AREAL COVERAGE AND VISIBILITIES. WHERE FOG
WAS SLOWEST TO ERODE...FROM TORRINGTON...TO SCOTTSBLUFF AND TO
ALLIANCE...INCLUDING OVER THE SNOWFIELD...3 PM TEMPERATURE AND
DEWPOINT SPREADS ARE ONLY 2 TO 5 DEGREES WITH CLEARING MID LEVEL
SKIES NOTED ON VISIBLE SATELLITE IMAGERY...THUS EXPECT FOG TO
DEVELOP RATHER QUICKLY AND SPREAD OVER AFOREMENTIONED LOCALES IN
THE LATE AFTERNOON AND EARLY EVENING HOURS.

LOW LEVELS AND BOUNDARY LAYER SATURATE UP DECENTLY
OVERNIGHT...ESPECIALLY OVER OUR WESTERN COUNTIES OF CARBON AND
ALBANY...AND MID AFTERNOON TEMPERATURE DEWPOINT SPREADS ARE ONLY
AROUND 7 DEGREES AT RAWLINS AND LARAMIE...ALONG WITH MID LEVEL
CLEARING PROGGED...THUS EXPECT RATHER EXTENSIVE FOG TO DEVELOP LATE
THIS EVENING AND OVERNIGHT ACROSS OUR WESTERN COUNTIES.

NEGATIVELY TILTED SHORTWAVE TROUGH ALOFT MOVES FROM WESTERN WYOMING
THIS AFTERNOON...TO NORTHWEST WYOMING BY MIDNIGHT AND TO CENTRAL
MONTANA BY DAYBREAK...BASED ON SATELLITE AND RADAR TRENDS...EXPECT
INCREASING AREAL COVERAGE OF SNOW SHOWERS THIS EVENING ACROSS OUR
WYOMING COUNTIES...ESPECIALLY OVER AND NEAR THE SNOWY AND SIERRA
MADRE RANGES...WITH A SLOW CESSATION AND DECREASE IN AREAL SNOW
COVERAGE LATE THIS EVENING AND OVERNIGHT. MAY EVEN SEE A FEW
FLAKES ALONG AND EAST OF INTERSTATE 25...THOUGH COVERAGE LOOKS
QUITE MINIMAL.

WEDNESDAY...SPLIT TROUGHS ALOFT MOVE ACROSS OUR REGION WITH THE
BULK OF SNOW AND DEEPER MOISTURE LOCATED OVER COLORADO...THOUGH
OUR SNOWY AND SIERRA MADRE RANGES WILL SEE SCATTERED OROGRAPHIC
SNOW SHOWERS...MOSTLY DRY ELSEWHERE.

WEDNESDAY NIGHT...NORTHERN STREAM SHORTWAVE TROUGH ALOFT MOVES OVER
THE WESTERN DAKOTAS...WITH THE SOUTHERN STREAM SHORTWAVE TROUGH
ALOFT MOVING OVER WESTERN KANSAS...THUS MINIMAL COVERAGE OF SNOW
SHOWERS OVER OUR COUNTIES...MAINLY OVER THE SNOWY AND SIERRA MADRE
RANGES...DRY ELSEWHERE.

THURSDAY...PSEUDO CYCLONIC FLOW ALOFT CONTINUES OVER OUR COUNTIES
WITH ONE SHORTWAVE ALOFT OVER THE FOUR CORNERS WITH MOST OF THAT
SHORTWAVE TROUGH SNOW OVER WESTERN COLORADO...THOUGH WILL SEE SOME
OROGRAPHIC SNOW SHOWERS OVER OUR SNOWY AND SIERRA MADRE RANGES...
DRY ELSEWHERE.

THURSDAY NIGHT...FAST MOVING...MOISTURE STARVED SHORTWAVE TROUGH
ALOFT MOVES ACROSS OUR COUNTIES...THOUGH WITH MINIMAL LOW AND MID
LEVEL MOISTURE...ONLY SOME ISOLATED MOUNTAIN SNOW SHOWERS ON TAP.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 243 PM MST TUE DEC 16 2014

SHORTWAVE TROUGH WILL MOVE OVERHEAD ON FRIDAY UNDER WEAK NORTHWEST
FLOW. MODELS KEEP THE HIGHEST LLVL MOISTURE OVER THE MOUNTAINS THRU
THE DAY WHICH IS REASONABLE IN THIS FLOW PATTERN...SO KEPT SNOW
CHANCES CONFINED TO THE SNOWY AND SIERRA MADRES MOUNTAINS. ANOTHER
WEAK SHORTWAVE TROUGH WILL MOVE THROUGH ON SATURDAY/SATURDAY NIGHT
WITH A SLIGHTLY MORE NORTHERLY TRACK...SO COULD SEE LIGHT SNOW
SHOWERS RETURNING TO THE MOUNTAINS INCLUDING THE NORTHERN LARAMIE
RANGE THROUGH THIS TIME. WINDS ALOFT WILL BEGIN TO INCREASE SUNDAY
AND MONDAY AS A STRONG EASTERN PAC HIGH BUILDS IN FROM THE WEST. THE
STORM TRACK WILL THUS SHIFT OVER THE NORTHERN ROCKIES AND HIGH
PLAINS THROUGH THE EARLY PART OF THE WEEK...WITH WINDY CONDITIONS
AND INCREASING COVERAGE OF SNOW SHOWERS EXPECTED. THE NOSE OF A 150+
KT JET WILL MOVE OVERHEAD MONDAY...WITH A RATHER VIGOROUS VORT MAX
MOVING FROM THE NORTHERN ROCKIES INTO THE CENTRAL PLAINS IN THE LFQ
REGION OF THE JET. STILL LOOKS FAVORABLE FOR MORE WIDESPREAD SNOW
SHOWERS OVER THE CWA ON MONDAY...ESPECIALLY OVER THE MOUNTAINS AND
NORTHERN PLAINS FROM DOUGLAS TO ALLIANCE IN BETTER PROXIMITY TO THE
JET DIFLUENCE AND LIFT FROM THE VORT MAX. THE LLVL GRADIENT WILL
INCREASE IN ADVANCE OF THE WAVE AS THE LEESIDE TROUGH DEEPENS AS
WELL...SO SHOULD ALSO SEE WINDS BECOME MODERATE TO STRONG LATE
SUNDAY THROUGH MONDAY. THE ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE EASTERN PLAINS SOMETIME LATE MONDAY...AND SHOULD STALL HERE
THROUGH TUESDAY. WINDY CONDITIONS WITH CHANCES FOR LIGHT SNOW WILL
CONTINUE OVER THE MOUNTAINS WITH RAIN/SNOW MIX OVER THE PLAINS AS A
RESULT. TEMPS THROUGH THE PERIOD WILL REMAIN AROUND NORMAL FOR THIS
TIME OF YEAR...WITH A SLIGHT BUMP UPWARDS AS DOWNSLOPE WINDS KICK IN
FOR MONDAY AND TUESDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 501 PM MST TUE DEC 16 2014

FOG WILL BE THE MAIN AVIATION CONCERN FOR MOST TERMINALS ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. LINGERING LIGHT SNOW
SHOWERS SHOULD HAVE LITTLE IMPACT. EXPECT IFR/LIFR CIGS AND VSBYS
TO DEVELOP BETWEEN 03Z AND 06Z AND PERSIST THROUGH THE NIGHT. THE
MOST LIKELY AREA TO SEE LOCALLY DENSE FOG WITH VSBYS LESS THAN ONE
QUARTER OF A MILE WILL BE THE PLATTE RIVER VALLEY WITH LIGHT
UPVALLEY WINDS...INCLUDING BFF. THE PANHANDLE SITES COULD SEE IFR
CONDITIONS WELL INTO THE AFTERNOON ON WED.

&&

.FIRE WEATHER...
ISSUED AT 243 PM MST TUE DEC 16 2014

MINIMAL ISSUES DUE TO PROJECTED HUMIDITIES AND WINDS.

&&

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

$$

SHORT TERM...RUBIN
LONG TERM...RJM
AVIATION...CLH
FIRE WEATHER...RUBIN





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