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000
FXUS65 KCYS 200415
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1015 PM MDT WED JUN 19 2013

.UPDATE...
ISSUED AT 900 PM MDT WED JUN 19 2013

DESPITE THE VERY HIGH CAPE VALUES (3000-4000 J/KG) ACROSS THE
NEBRASKA PANHANDLE THIS EVENING...STORMS HAVE FAILED TO INITIATE
AND STRENGTHEN. A FEW WEAK SHOWERS/STORMS HAVE OCCURRED OVER THE
SOUTHEAST WYOMING PLAINS AND MOVED INTO THE MORE UNSTABLE AIRMASS
TO THE EAST OF THE DRYLINE...BUT THEN FAILED TO INTENSIFY. IT
APPEARS THAT THE WARM TEMPS ALOFT HAVE BEEN INHIBITING DEEP
CONVECTION. STILL KEPT SLIGHT CHANCE POPS IN FOR THE PANHANDLE AND
NIOBRARA AND CONVERSE COUNTIES THROUGH 06Z.  STORMS HAVE BEEN
CONTINUING INTO THE HOURS AFTER SUNSET OVER THE PAST WEEK. THERE
IS CURRENTLY ONE LONE CELL IN COLORADO TO THE SOUTH OF KIMBALL
THAT MAY MOVE INTO THE SOUTHERN PANHANDLE OVER THE NEXT FEW HOURS.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 230 PM MDT WED JUN 19 2013

FORECAST CHALLENGES THROUGH THE SHORT TERM DEAL WITH WINDS THROUGH
FRIDAY.

CURRENTLY...SOUTHWEST WINDS PRETTY STRONG OUT WEST OF THE LARAMIE
RANGE THIS AFTERNOON. GETTING WIND GUSTS OVER 40 MPH IN CARBON
COUNTY...EXTENDING TO THE WEST SLOPES OF THE LARAMIE RANGE. VERY
DRY OUT THAT WAY...RAWLINS REPORTING 6 PERCENT HUMIDITY AT 1 PM
THIS AFTERNOON...LARAMIE 9 PERCENT. LATEST SPC MESOANALYSIS SHOWING
A CAP STILL IN PLACE OUT IN THE PANHANDLE...WITH CONVECTIVE
INHIBITION OF -25 TO -50 J/KG. VISIBLE IMAGERY SHOWING PRETTY MUCH
CLEAR SKIES...WITH NO CU DEVELOPMENT ALL ALONG THE FRONT RANGE.

THERE IS A SMALL WINDOW LATE THIS AFTERNOON WHERE THE SOUTHERN
PANHANDLE SEES A BREAK IN THE CAP. WITH 700MB TEMPERATURES
CLIMBING TO +16C...CONFIDENCE IS NOT HIGH THAT THE CAP WILL BE
BROKEN. LATEST HRRR FORECAST DOES SHOW A FEW CELLS DEVELOPING
ACROSS GOSHEN COUNTY AND THE NORTHERN PANHANDLE AFTER 00Z...SO
WILL KEEP THE SLIGHT CHANCE POPS INHERITED GOING FOR A COUPLE
HOURS THROUGH THE 03Z TIME FRAME.

WINDS EASE THIS EVENING WITH THE GFS 700MB WINDS DECREASING TO
15-20KTS AFTER 06Z. FOR THURSDAY...WINDS TO REMAIN FAIRLY LIGHT
OUT WEST THROUGH THE MORNING AND MID AFTERNOON. THEY DO START
PICKING UP AFTER 00Z...INCREASING TO 25 TO 30KTS BY 06Z. LOOKS
LIKE A PRETTY WINDY DAY ONCE AGAIN OUT WEST OF THE LARAMIE RANGE.

FRIDAY WE START TO SEE A CHANGE AS THE UPPER LOW OVER WESTERN
MONTANA OPENS UP AND A FAIRLY STRONG SHORTWAVE TRACKS INTO WESTERN
WYOMING. 700MB WINDS OUT WEST TO REMAIN 25 TO 35 KTS...BUT WINDS
OVER THE PANHANDLE TURN MORE EASTERLY AS THE LEE SIDE TROUGH
DEEPENS. DEPENDING ON WHICH MODEL YOU LOOK AT...WE COULD SEE
SHOWERS AND THUNDERSTORMS DEVELOPING OUT THAT WAY FRIDAY
AFTERNOON. THE NEW ECMWF PAINTING A WIDESPREAD AREA OF QPF OVER
THE NORTHERN PANHANDLE FRIDAY AFTERNOON AND EVENING. GFS IS DRY
AND LATEST NAM/WRF SIMILAR TO THE ECMWF...THOUGH NOT AS WIDESPREAD
ON PRECIP.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)

ISSUED AT 345 PM MDT WED JUN 19 2013

PESKY PACIFIC NORTHWEST LOW PRESSURE WILL FINALLY BEGIN TO FILL
THIS WEEKEND AS IT EJECTS INTO THE NRN PLAINS. AN ASSOCIATED
SHORTWAVE WILL TRAVERSE THRU WYOMING ON SATURDAY. MEDIUM RANGE
GUIDANCE VARIES SIGNIFICANTLY ON THE AMOUNT OF AVAILABLE LLVL
MOISTURE ACROSS THE AREA ON SATURDAY. THE GFS IS SIGNIFICANTLY
DRIER FOR MUCH OF THE CWA AS MUCH OF THE MOISTURE IS SHUNTED
MOISTURE ACROSS EASTERN ZONES. MEANWHILE...THE ECMWF IS DEEPER AND
FURTHER WEST WITH THE MOISTURE...WHICH WOULD BACK UP CONVECTION
INTO THE EASTERN SOUTHEAST WYOMING PLAINS. FOR NOW HAVE KEPT
AFTERNOON SHOWER AND THUNDERSTORM CHANCES GOING FOR MUCH OF THE
EASTERN PLAINS. INSTABILITY PARAMETERS WOULD CERTAINLY BE
SUPPORTIVE OF SEVERE WEATHER POTENTIAL IF THE LLVL MOISTURE
MATERIALIZES. THIS WILL BE ESPECIALLY TRUE ACROSS THE WESTERN
NEBRASKA PANHANDLE SATURDAY AFTERNOON AND EARLY EVENING.

LLVL MOISTURE MAY HANG AROUND AGAIN ON SUNDAY AFTERNOON...AS PROGD
INSTABILITIES REMAIN ELEVATED OUT ON THE EASTERN PLAINS. MAIN
QUESTION WILL BE WHETHER OR NOT THERE WILL BE A FOCAL POINT TO
PROVIDE LIFT. HOWEVER...RECENT MODEL GUIDANCE DOES SHOW AT THE
ANOTHER WEAK SHORTWAVE PERHAPS LATE SUNDAY. FOR NOW HAVE ADDED
SHOWER AND THUNDERSTORM CHANCES ALONG AND EAST OF THE LARAMIE
RANGE DURING THE AFTERNOON...SPREADING INTO THE WESTERN NEBRASKA
PANHANDLE BY EARLY EVENING.

FLOW TURNS DRIER AND MORE SOUTHWESTERLY FOR MONDAY THROUGH
WEDNESDAY. SO HAVE THE FIRST HALF OF NEXT WEEK DRY FOR NOW. FIRE
WEATHER CONCERNS WILL BE HEIGHTENED GIVEN THIS TRANSITION TO DRY
CONDITIONS.

PROGD H7 TEMPERATURES WILL HOVER BETWEEN 13-15C THRU MUCH OF THE
PERIOD...WHICH WILL YIELD AFTERNOON HIGHS GENERALLY IN THE 80S
ACROSS SOUTHEAST WYOMING WITH 80S AND LOW/MID 90S ACROSS THE
WESTERN NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 1005 PM MDT WED JUN 19 2013

VFR PREVAILS. PACIFIC ORIGIN COLD FRONT MOVES THROUGH TONIGHT
WITH WINDS BECOMING WEST AND NORTHWEST. SURFACE LOW PRESSURE
DEVELOPS ON THURSDAY ACROSS EASTERN COLORADO WITH WINDS BECOMING
SOUTH AND SOUTHEAST.

&&

.FIRE WEATHER...
ISSUED AT 230 PM PM MDT WED JUN 19 2013

SOUTHWEST WINDS OF 20 TO 30 MPH SUSTAINED WITH GUSTS TO 40 MPH
WILL CONTINUE THIS AFTERNOON WEST OF THE LARAMIE RANGE. AFTERNOON
HUMIDITIES HAVE ALREADY FALLEN INTO THE SINGLE DIGITS. WINDS ARE
EXPECTED TO EASE BY MID EVENING. POOR HUMIDITY RECOVERIES EXPECTED
OVERNIGHT WEST OF THE LARAMIE RANGE WITH GOOD RECOVERIES IN THE
PANHANDLE. A DRY FORECAST THROUGH SATURDAY WITH WINDS INCREASING
AGAIN FRIDAY AFTERNOON. THIS DUE TO A LOW PRESSURE SYSTEM TRACKING
THROUGH MONTANA. THIS LOW WILL DRAG A COLD FRONT THROUGH THE AREA
SATURDAY WITH SCATTERED CHANCES FOR SHOWERS AND THUNDERSTORMS IN
THE PANHANDLE.

&&

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

$$

UPDATE...FINCH
SHORT TERM...CLAYCOMB
LONG TERM...HAHN
AVIATION...RUBIN
FIRE WEATHER...CLAYCOMB