559 
FXUS65 KCYS 181028
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
427 AM MDT TUE JUN 18 2013

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 400 AM MDT TUE JUN 18 2013

UPPER AIR ANALYSIS SHOWED THE RIDGE THAT WAS OVER THE INTERMOUNTAIN
WEST THE PAST FEW DAYS MOVED EAST AND WAS LOCATED OVER THE ROCKIES.
A LARGE CLOSED UPPER LOW WAS APPROACHING THE PACIFIC NORTHWEST COAST.
A SERIES OF SHORTWAVES WAS RIDING OVER AND DOWN THE EAST SIDE OF THE
TROUGH THROUGH THE GREAT PLAINS. SCATTERED TSTORMS LATE MONDAY OVER
EASTERN PARTS OF THE CWFA ORGANIZED INTO A SMALL MCS OVER CENTRAL
NEBRASKA DURING THE OVERNIGHT. IN THE WAKE OF THIS SYSTEM...SKIES
WERE MOSTLY CLEAR...EXCEPT FOR PATCHY LOW CLOUDS AND FOG FORMING
OVER THE SOUTHERN LARAMIE RANGE. PREVAILING SURFACE WINDS WERE
VARIABLE AROUND 10 MPH. TEMPERATURES WERE IN THE 40S AND 50S.

THERE IS GENERAL CONSENSUS WITH THE LATEST MODEL GUIDANCE THAT THE
UPPER LEVEL PATTERN ACROSS THE LOWER 48 BECOMES MORE PROGRESSIVE
DURING THE NEXT 24 HOURS. THE UPPER LOW AND ITS ASSOCIATED TROUGH
MOVE ONSHORE TODAY...THEN NORTHEAST ACROSS THE GREAT BASIN AND
PACIFIC NORTHWEST TONIGHT AND WEDNESDAY. THIS WILL IN TURN SHUNT
THE UPPER RIDGE AXIS ALONG THE FRONT RANGE EASTWARD INTO THE GREAT
PLAINS ON WEDNESDAY. ANOTHER SHORTWAVE OVER UTAH TRACKS NORTHEAST
THROUGH WYOMING TODAY AND WESTERN NEBRASKA TONIGHT. THIS WAVE WILL
ENHANCE THE LARGE SCALE LIFT FOR ANOTHER CONVECTIVELY ACTIVE 
AFTERNOON AND EVENING FROM THE LARAMIE RANGE EASTWARD. SOUTHEASTERLY
LOW LEVEL WINDS STRENGTHEN TO 25 KT THIS AFTERNOON OVER THE HIGH
PLAINS. TSTORM DEVELOPMENT WILL TAKE PLACE BY MID AFTERNOON OVER
THE HIGHER TERRAIN...THEN MOVE ONTO THE PLAINS DURING THE LATE
AFTERNOON AND EARLY EVENING. A MODERATELY UNSTABLE ENVIRONMENT
/SBCAPES 1500-2000 J/KG/ WITH BULK SHEAR OF 30 TO 40 KT WILL
SUPPORT SCATTERED STRONG TO SEVERE TSTORMS PRODUCING HAIL AND
DAMAGING WINDS FROM THE EASTERN PLAINS INTO THE NEBRASKA 
PANHANDLE...MORE SPECIFICALLY EAST OF A DOUGLAS TO CHEYENNE LINE.
THE TSTORMS WILL EXIT THE WESTERN PANHANDLE LATER THIS EVENING.
TODAY'S HIGH TEMPERATURES WILL BE ABOUT 5 DEGREES WARMER THAN
MONDAY AS 700MB TEMPERATURES INCREASE TO 11 TO 14C DURING THE
AFTERNOON.

WEDNESDAY WILL FEATURE WARMER AND DRIER CONDITIONS WITH SOUTHWESTERLY
FLOW DOMINATING THE REGION ON THE WEST SIDE OF THE UPPER RIDGE.
BUFR SOUNDING DATA INDICATES THAT THE MID LEVELS WILL BE SUFFICIENTLY
CAPPED TO PRECLUDE DEEP MOIST CONVECTION. HIGH TEMPERATURES WILL
BE 5 TO 10 DEGREES WARMER WITH 700MB TEMPERATURES AROUND 16C.
A SURFACE TROUGH OVER THE EASTERN PLAINS WILL DEEPEN THROUGHOUT
THE DAY...WITH GUSTY SOUTHWEST WINDS DEVELOPING WEST OF THE
LARAMIE RANGE.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 400 AM MDT TUE JUN 18 2013

WESTERLY SFC WINDS ALONG WITH DRY AIR ALOFT WILL KEEP DRY CONDITIONS 
IN PLACE WEDNESDAY NIGHT THROUGH EARLY THURSDAY. A RATHER VIGOROUS 
SHORTWAVE MOVING TOWARD THE AREA ON THURSDAY WILL BRING SOME MID AND 
UPPER LEVEL MOISTURE TO THE FORECAST AREA ALONG WITH RETURN OF
SOUTHEAST SFC FLOW ACROSS THE EASTERN PLAINS. CONVERGENCE ALONG THE 
LARAMIE RANGE COMBINED WITH THE INCREASE IN MOISTURE SHOULD 
CONTRIBUTE TO SOME CONVECTION OVER THE LARAMIE RANGE...WITH A FEW 
POSSIBLY DEVELOPING INTO WEAK THUNDERSTORMS. VERY WARM TEMPERATURES 
ALOFT WILL KEEP CHANCES LOW THOUGH...AND CONFINED TO THE HIGHER 
TERRAIN. SOUTHWEST WINDS WEST OF THE LARAMIE RANGE WILL BE GUSTING 
30 TO 40 MPH AS THE SHORTWAVE APPROACHES...AND WITH HUMIDITIES 
DROPPING INTO THE UPPER SINGLE DIGITS TO LOW TEENS...WILL KEEP FIRE 
WEATHER CONCERNS ELEVATED FOR THIS AREA. THIS ENERGY WILL MOVE TO 
THE NORTHEAST BY FRIDAY MORNING...WITH YET ANOTHER WAVE MOVING 
ACROSS WESTERN WYOMING FRIDAY AFTERNOON. CONTINUED WARM 700 MB TEMPS 
IN THE MID TEENS WITH OVERALL LACK OF MOISTURE WILL KEEP CONVECTION 
MINIMAL ONCE AGAIN FOR FRIDAY...ALTHOUGH ECMWF CONTINUES TO SHOW 
LLVL RETURN MOISTURE MUCH SOONER THAN THE GFS. THEREFORE WILL KEEP 
SOME LOW CHANCES FOR TSTORMS MAINLY FOR EAST CENTRAL WYOMING AND THE 
NORTHERN NEBRASKA PANHANDLE ON FRIDAY.

THESE DIFFERENCES ARE ATTRIBUTED TO VARYING MODEL SOLUTIONS OF THE
STRONG UPPER LOW OVER PAC NW THAT WILL SLOWLY MOVE NORTHEAST INTO
THE NORTHERN ROCKIES THURSDAY THROUGH SATURDAY. WILL MAINTAIN A
BLEND FOR THE REMAINDER OF THE FORECAST AS THE EASTWARD PROGRESSION
AND BREAKDOWN OF THIS LOW VARIES SIGNIFICANTLY...EACH WITH DIFFERENT
IMPLICATIONS FOR THE FORECAST AREA. THE GENERAL TREND HOWEVER
MAINTAINS VERY WARM TEMPERATURES ALONG WITH A BETTER FETCH OF
PACIFIC MOISTURE MOVING OVERHEAD...SO WILL KEEP LOW CHANCES FOR
SHOWERS AND THUNDERSTORMS MAINLY ALONG AND EAST OF THE LARAMIE RANGE 
THROUGH SUNDAY...WITH MONDAY REMAINING DRY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 400 AM MDT TUE JUN 18 2013

UPSLOPE EASTERLY LOW LEVEL FLOW WILL DEVELOP AREAS OF LOW CLOUDS AND
PATCHY FOG OVER THE SOUTHERN LARAMIE RANGE AND FAR SOUTHEAST WYOMING
PLAINS EARLY THIS MORNING. OTHERWISE...VFR CONDITIONS WILL PREVAIL
WITH GUSTY SOUTHERLY WINDS FROM LATE MORNING THROUGH EARLY EVENING.
ISOLATED TO SCATTERED THUNDERSTORMS PRODUCING LOCAL MVFR CEILINGS
AND VISIBILITIES WILL DEVELOP OVER THE MOUNTAINS AND SPREAD EAST
ONTO THE PLAINS. SOME STRONG TO SEVERE STORMS WILL BE POSSIBLE
EAST OF A DOUGLAS TO CHEYENNE LINE THIS AFTERNOON AND EVENING.

&&

.FIRE WEATHER...
ISSUED AT 400 AM MDT TUE JUN 18 2013

HIGH PRESSURE IN THE UPPER ATMOSPHERE WILL MOVE FROM THE FRONT RANGE
TODAY TO THE GREAT PLAINS WEDNESDAY. SOUTHWESTERLY WINDS WILL USHER
IN MUCH DRIER AIR WEDNESDAY FOR THE WYOMING DISTRICT. A DRY LINE
WILL REMAIN NEARLY STATIONARY OVER THE WESTERN NEBRASKA PANHANDLE
THROUGH THE END OF THE WEEK. GUSTY WEST TO SOUTHWEST WINDS COMBINED
WITH VERY LOW RELATIVE HUMIDITIES AND WARM TEMPERATURES WILL YIELD
AN ELEVATED FIRE DANGER WEST OF THE LARAMIE RANGE. ISOLATED TO
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL DEVELOP ONCE
AGAIN OVER THE MOUNTAINS EARLY THIS AFTERNOON...THEN SPREAD EAST
ONTO THE EASTERN PLAINS AND WESTERN PANHANDLE BY LATE AFTERNOON.
SOME OF THE STORMS EAST OF A LINE FROM DOUGLAS TO CHEYENNE MAY BE
STRONG TO SEVERE WITH DAMAGING WINDS AND LARGE HAIL. FOR THE UPCOMING
WEEKEND...ISOLATED LATE DAY THUNDERSTORMS WILL BE POSSIBLE...MAINLY
NORTHERN AND EASTERN PORTIONS OF THE DISTRICT.

&&

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

$$

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

619 
FXUS65 KCYS 181027
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
427 AM MDT TUE JUN 18 2013

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 320 AM MDT TUE JUN 18 2013

UPPER AIR ANALYSIS SHOWED THE RIDGE THAT WAS OVER THE INTERMOUNTAIN
WEST THE PAST FEW DAYS MOVED EAST AND WAS LOCATED OVER THE ROCKIES.
A LARGE CLOSED UPPER LOW WAS APPROACHING THE PACIFIC NORTHWEST COAST.
A SERIES OF SHORTWAVES WAS RIDING OVER AND DOWN THE EAST SIDE OF THE
TROUGH THROUGH THE GREAT PLAINS. SCATTERED TSTORMS LATE MONDAY OVER
EASTERN PARTS OF THE CWFA ORGANIZED INTO A SMALL MCS OVER CENTRAL
NEBRASKA DURING THE OVERNIGHT. IN THE WAKE OF THIS SYSTEM...SKIES
WERE MOSTLY CLEAR...EXCEPT FOR PATCHY LOW CLOUDS AND FOG FORMING
OVER THE SOUTHERN LARAMIE RANGE. PREVAILING SURFACE WINDS WERE
VARIABLE AROUND 10 MPH. TEMPERATURES WERE IN THE 40S AND 50S.

THERE IS GENERAL CONSENSUS WITH THE LATEST MODEL GUIDANCE THAT THE
UPPER LEVEL PATTERN ACROSS THE LOWER 48 BECOMES MORE PROGRESSIVE
DURING THE NEXT 24 HOURS. THE UPPER LOW AND ITS ASSOCIATED TROUGH
MOVE ONSHORE TODAY...THEN NORTHEAST ACROSS THE GREAT BASIN AND
PACIFIC NORTHWEST TONIGHT AND WEDNESDAY. THIS WILL IN TURN SHUNT
THE UPPER RIDGE AXIS ALONG THE FRONT RANGE EASTWARD INTO THE GREAT
PLAINS ON WEDNESDAY. ANOTHER SHORTWAVE OVER UTAH TRACKS NORTHEAST
THROUGH WYOMING TODAY AND WESTERN NEBRASKA TONIGHT. THIS WAVE WILL
ENHANCE THE LARGE SCALE LIFT FOR ANOTHER CONVECTIVELY ACTIVE 
AFTERNOON AND EVENING FROM THE LARAMIE RANGE EASTWARD. SOUTHEASTERLY
LOW LEVEL WINDS STRENGTHEN TO 25 KT THIS AFTERNOON OVER THE HIGH
PLAINS. TSTORM DEVELOPMENT WILL TAKE PLACE BY MID AFTERNOON OVER
THE HIGHER TERRAIN...THEN MOVE ONTO THE PLAINS DURING THE LATE
AFTERNOON AND EARLY EVENING. A MODERATELY UNSTABLE ENVIRONMENT
/SBCAPES 1500-2000 J/KG/ WITH BULK SHEAR OF 30 TO 40 KT WILL
SUPPORT SCATTERED STRONG TO SEVERE TSTORMS PRODUCING HAIL AND
DAMAGING WINDS FROM THE EASTERN PLAINS INTO THE NEBRASKA 
PANHANDLE...MORE SPECIFICALLY EAST OF A DOUGLAS TO CHEYENNE LINE.
THE TSTORMS WILL EXIT THE WESTERN PANHANDLE LATER THIS EVENING.
TODAY'S HIGH TEMPERATURES WILL BE ABOUT 5 DEGREES WARMER THAN
MONDAY AS 700MB TEMPERATURES INCREASE TO 11 TO 14C DURING THE
AFTERNOON.

WEDNESDAY WILL FEATURE WARMER AND DRIER CONDITIONS WITH SOUTHWESTERLY
FLOW DOMINATING THE REGION ON THE WEST SIDE OF THE UPPER RIDGE.
BUFR SOUNDING DATA INDICATES THAT THE MID LEVELS WILL BE SUFFICIENTLY
CAPPED TO PRECLUDE DEEP MOIST CONVECTION. HIGH TEMPERATURES WILL
BE 5 TO 10 DEGREES WARMER WITH 700MB TEMPERATURES AROUND 16C.
A SURFACE TROUGH OVER THE EASTERN PLAINS WILL DEEPEN THROUGHOUT
THE DAY...WITH GUSTY SOUTHWEST WINDS DEVELOPING WEST OF THE
LARAMIE RANGE.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 400 AM MDT TUE JUN 18 2013

WESTERLY SFC WINDS ALONG WITH DRY AIR ALOFT WILL KEEP DRY CONDITIONS 
IN PLACE WEDNESDAY NIGHT THROUGH EARLY THURSDAY. A RATHER VIGOROUS 
SHORTWAVE MOVING TOWARD THE AREA ON THURSDAY WILL BRING SOME MID AND 
UPPER LEVEL MOISTURE TO THE FORECAST AREA ALONG WITH RETURN OF
SOUTHEAST SFC FLOW ACROSS THE EASTERN PLAINS. CONVERGENCE ALONG THE 
LARAMIE RANGE COMBINED WITH THE INCREASE IN MOISTURE SHOULD 
CONTRIBUTE TO SOME CONVECTION OVER THE LARAMIE RANGE...WITH A FEW 
POSSIBLY DEVELOPING INTO WEAK THUNDERSTORMS. VERY WARM TEMPERATURES 
ALOFT WILL KEEP CHANCES LOW THOUGH...AND CONFINED TO THE HIGHER 
TERRAIN. SOUTHWEST WINDS WEST OF THE LARAMIE RANGE WILL BE GUSTING 
30 TO 40 MPH AS THE SHORTWAVE APPROACHES...AND WITH HUMIDITIES 
DROPPING INTO THE UPPER SINGLE DIGITS TO LOW TEENS...WILL KEEP FIRE 
WEATHER CONCERNS ELEVATED FOR THIS AREA. THIS ENERGY WILL MOVE TO 
THE NORTHEAST BY FRIDAY MORNING...WITH YET ANOTHER WAVE MOVING 
ACROSS WESTERN WYOMING FRIDAY AFTERNOON. CONTINUED WARM 700 MB TEMPS 
IN THE MID TEENS WITH OVERALL LACK OF MOISTURE WILL KEEP CONVECTION 
MINIMAL ONCE AGAIN FOR FRIDAY...ALTHOUGH ECMWF CONTINUES TO SHOW 
LLVL RETURN MOISTURE MUCH SOONER THAN THE GFS. THEREFORE WILL KEEP 
SOME LOW CHANCES FOR TSTORMS MAINLY FOR EAST CENTRAL WYOMING AND THE 
NORTHERN NEBRASKA PANHANDLE ON FRIDAY.

THESE DIFFERENCES ARE ATTRIBUTED TO VARYING MODEL SOLUTIONS OF THE
STRONG UPPER LOW OVER PAC NW THAT WILL SLOWLY MOVE NORTHEAST INTO
THE NORTHERN ROCKIES THURSDAY THROUGH SATURDAY. WILL MAINTAIN A
BLEND FOR THE REMAINDER OF THE FORECAST AS THE EASTWARD PROGRESSION
AND BREAKDOWN OF THIS LOW VARIES SIGNIFICANTLY...EACH WITH DIFFERENT
IMPLICATIONS FOR THE FORECAST AREA. THE GENERAL TREND HOWEVER
MAINTAINS VERY WARM TEMPERATURES ALONG WITH A BETTER FETCH OF
PACIFIC MOISTURE MOVING OVERHEAD...SO WILL KEEP LOW CHANCES FOR
SHOWERS AND THUNDERSTORMS MAINLY ALONG AND EAST OF THE LARAMIE
RANGE THROUGH SUNDAY...WITH MONDAY REMAINING DRY.



&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 400 AM MDT TUE JUN 18 2013

UPSLOPE EASTERLY LOW LEVEL FLOW WILL DEVELOP AREAS OF LOW CLOUDS AND
PATCHY FOG OVER THE SOUTHERN LARAMIE RANGE AND FAR SOUTHEAST WYOMING
PLAINS EARLY THIS MORNING. OTHERWISE...VFR CONDITIONS WILL PREVAIL
WITH GUSTY SOUTHERLY WINDS FROM LATE MORNING THROUGH EARLY EVENING.
ISOLATED TO SCATTERED THUNDERSTORMS PRODUCING LOCAL MVFR CEILINGS
AND VISIBILITIES WILL DEVELOP OVER THE MOUNTAINS AND SPREAD EAST
ONTO THE PLAINS. SOME STRONG TO SEVERE STORMS WILL BE POSSIBLE
EAST OF A DOUGLAS TO CHEYENNE LINE THIS AFTERNOON AND EVENING.

&&

.FIRE WEATHER...
ISSUED AT 400 AM MDT TUE JUN 18 2013

HIGH PRESSURE IN THE UPPER ATMOSPHERE WILL MOVE FROM THE FRONT RANGE
TODAY TO THE GREAT PLAINS WEDNESDAY. SOUTHWESTERLY WINDS WILL USHER
IN MUCH DRIER AIR WEDNESDAY FOR THE WYOMING DISTRICT. A DRY LINE
WILL REMAIN NEARLY STATIONARY OVER THE WESTERN NEBRASKA PANHANDLE
THROUGH THE END OF THE WEEK. GUSTY WEST TO SOUTHWEST WINDS COMBINED
WITH VERY LOW RELATIVE HUMIDITIES AND WARM TEMPERATURES WILL YIELD
AN ELEVATED FIRE DANGER WEST OF THE LARAMIE RANGE. ISOLATED TO
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL DEVELOP ONCE
AGAIN OVER THE MOUNTAINS EARLY THIS AFTERNOON...THEN SPREAD EAST
ONTO THE EASTERN PLAINS AND WESTERN PANHANDLE BY LATE AFTERNOON.
SOME OF THE STORMS EAST OF A LINE FROM DOUGLAS TO CHEYENNE MAY BE
STRONG TO SEVERE WITH DAMAGING WINDS AND LARGE HAIL. FOR THE UPCOMING
WEEKEND...ISOLATED LATE DAY THUNDERSTORMS WILL BE POSSIBLE...MAINLY
NORTHERN AND EASTERN PORTIONS OF THE DISTRICT.

&&

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

$$

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