120 FXUS65 KCYS 121001 AFDCYS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 401 AM MDT WED JUN 12 2013 .SHORT TERM...(TODAY AND THURSDAY) ISSUED AT 223 AM MDT WED JUN 12 2013 CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE POTENT SHORTWAVE DISTURBANCE ALOFT...WHICH AIDED IN SEVERE TSTORM DEVELOPMENT ACROSS THE DAKOTAS AND WESTERN NEBRASKA LAST NIGHT...PUSHING EASTWARD INTO THE NORTHERN PLAINS AS A SHORT WAVE RIDGE MOVES INTO THE FORECAST AREA BEHIND THE DISTURBANCE. DRIER AIR HAS MOVED INTO SOUTHEAST WYOMING AND THE SOUTHERN NEBRASKA PANHANDLE EARLY THIS MORNING...WHICH SHOULD GREATLY LIMIT DAYTIME CONVECTION WITH ADDITIONAL MIDLEVEL SUBSIDENCE. HOWEVER...MODELS SHOW ANOTHER SHORTWAVE MOVING ACROSS THE HIGH PLAINS LATER TODAY AS A WEAK SURFACE TROUGH/MOISTURE GRADIENT DEVELOPS ALONG THE LARAMIE RANGE. ALTHOUGH LLVL INSTABILITY IS MARGINAL...KEPT A SLIGHT CHANCE OF SHOWERS AND TSTORMS ALONG AND JUST EAST OF THE LARAMIE RANGE TODAY WHERE EAST TO SOUTHEAST WINDS WILL DEVELOP AND BECOME BREEZY BY LATE THIS AFTERNOON. SOUTHWEST WINDS ARE EXPECTED WEST OF THE LARAMIE RANGE...AND MAY GUST TO 30-35 MPH AT TIMES. PATCHY FOG IS POSSIBLE ACROSS MOST OF THE WESTERN NEBRASKA PANHANDLE TONIGHT AND EARLY THURSDAY MORNING. OTHERWISE...THERE IS A BETTER CHANCE OF THUNDERSTORMS ON THURSDAY AS THE UPPER LEVEL FLOW BACKS INTO THE SOUTHWEST AHEAD OF A PACIFIC STORM SYSTEM PUSHING INTO THE PACIFIC NORTHWEST. THE LLVL CONVERGENCE BOUNDARY/MOISTURE GRADIENT WILL REMAIN NEAR THE LARAMIE RANGE DURING THE DAY...WITH PW/S INCREASING OVER 1.00 INCHES ACROSS WESTERN NEBRASKA. MODELS SHOW MUCH MORE LLVL INSTABILITY...WITH LI/S AS LOW AS -9C ACROSS NEBRASKA AND CAPE VALUES BETWEEN 2500 TO 3500 J/KG. A FEW STRONG THUNDERSTORMS ARE POSSIBLE THURSDAY AFTERNOON AS WELL. TEMPERATURES WILL REMAIN ABOVE NORMAL...WITH VERY LITTLE CHANGE IN HIGH TEMPERATURES WHICH RANGE FROM THE MID TO UPPER 80S ACROSS SOUTHEAST WYOMING TO THE LOW 90S ACROSS WESTERN NEBRASKA AND THE NORTH PLATTE RIVER VALLEY. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 401 AM MDT WED JUN 12 2013 WEATHER PATTERN WILL BE RELATIVELY PERSISTENT THROUGH EARLY NEXT WEEK WITH AN UPPER LEVEL TROUGH OVER THE NW CONUS AND A RIDGE INTO THE CENTRAL CONUS. RIDGE WILL FLATTEN OUT EARLY THIS WEEKEND AS UPPER LEVEL WAVE MOVES OUT OF THE PACIFIC NW AND INTO SOUTH CENTRAL CANADA BUT THE RIDGE WILL REBOUND BY EARLY NEXT WEEK. STARTING OFF THURSDAY EVENING THERE WILL BE A SMALL CHANCE FOR THUNDERSTORMS. COULD SEE AN ISOLATED SHOWER OR THUNDERSTORM OVER THE MOUNTAINS BUT THE MAIN CONCERN WILL BE ALONG THE EASTERN FRINGES OF THE FORECAST AREA IN THE NEBRASKA PANHANDLE. COULD SEE A FEW SEVERE THUNDERSTORMS BUT AT THIS TIME THE GREATEST INSTABILITY SHOULD BE EAST OF THE FORECAST AREA. FRIDAY LOOKS WARM AND DRY WITH WILL MINIMAL THUNDERSTORM CHANCES. MODELS SHOWING A WEAK SHORTWAVE SLIDING JUST SOUTH AND EAST OF THE AREA WITH A STRONGER WAVE NORTH ACROSS MONTANA. AS LONG AS THE PLACEMENT OF THESE FEATURES IS CORRECT THEN MOST OF THE AREA WILL STAY DRY. FRONTAL BOUNDARY WILL BRING A SHOT OF COOLER AIR FRIDAY NIGHT. HIGH TEMPERATURES SATURDAY SHOULD BE A GOOD 5 TO 10 DEGREES COOLER THAN FRIDAY...MAINLY IN THE 80S WITH SOME 70S WEST. TEMPERATURES WILL SLOWLY REBOUND SUNDAY THROUGH EARLY NEXT WEEK AS THE UPPER RIDGE BUILDS BACK INTO THE ROCKIES. CHANCES FOR THUNDERSTORMS WILL MAINLY FOCUS EAST OF THE LARAMIE RANGE...MAINLY LATE AFTERNOON AND EVENING. IT IS A BIT EARLY TO SAY...BUT GIVEN MODEL PROJECTIONS FOR INSTABILITY AND SHEAR...SEVERE THUNDERSTORMS LOOK TO BE GOOD POSSIBILITY SHOULD STORMS DEVELOP. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING) ISSUED AT 1029 PM MDT TUE JUN 11 2013 CONVECTION HAS MOVED OFF TO THE EAST THIS EVENING. STILL A CHANCE OF STRATUS OUT IN THE PANHANDLE TONIGHT...BUT HRRR NOT REALLY GOING WIDESPREAD WITH ITS FORECAST. WENT AHEAD WITH LOW MVFR IN THE KAIA AND KCDR TAFS TONIGHT AROUND 10Z THROUGH 15Z. LOOKS REALLY DRY WEDNESDAY. THE ONLY AREA THAT COULD SEE CONVECTION TOMORROW WOULD BE THE NORTHERN PANHANDLE. && .FIRE WEATHER... ISSUED AT 223 AM MDT WED JUN 12 2013 FIRE WEATHER CONCERNS WILL CONTINUE TO BE MINIMAL INTO THIS WEEKEND MAINLY DUE TO GREEN FUELS. A RIDGE OF HIGH PRESSURE WILL BUILD OVER THE AREA TODAY AND THURSDAY...WITH MOSTLY DRY CONDITIONS AND VERY WARM TEMPERATURES CONTINUING. DAYTIME MIN HUMIDITIES WILL REMAIN IN THE TEENS IN SOUTHEAST WYOMING...MAINLY WEST OF THE LARAMIE RANGE...WITH 20 TO 40 PERCENT EXPECTED ACROSS THE HIGH PLAINS INTO WESTERN NEBRASKA. WINDY CONDITIONS WILL CONTINUE ALONG AND WEST OF THE LARAMIE RANGE THROUGH THIS TIME AS WELL...WITH GUSTS OF 30 TO 40 MPH COMMON IN THE AFTERNOON EACH DAY. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...TJT LONG TERM...LIEBL AVIATION...CLAYCOMB FIRE WEATHER...TJT