Expires:No;;485809 FXUS63 KDDC 211756 AFDDDC AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 1256 PM CDT TUE MAY 21 2013 ...UPDATED FOR AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 116 AM CDT TUE MAY 21 2013 THE UPPER LEVEL FLOW ACROSS THE CENTRAL UNITED STATES WAS DOMINATED BY A DEEP UPPER LEVEL CYCLONE CENTERED IN SOUTHEAST NORTH DAKOTA. NORTH OF THE UPPER LEVEL CYCLONE, A BLOCKING UPPER LEVEL HIGH WAS CENTERED IN SASKATCHEWAN. ANOMALOUSLY STRONG MID LEVEL FLOW WITH WIND SPEEDS ABOVE 50KTS AT H5 PREVAILED FROM NEW MEXICO ACROSS OKLAHOMA TO THE UPPER MIDWEST. VERY COLD AIR ALOFT COVERED THE CENTRAL PLAINS AND ROCKIES WITH H5 TEMPERATURES AT OR BELOW -16C ACROSS A WIDE AREA. A VIGOROUS UPPER LEVEL TROUGH WAS EVIDENT ON SATELLITE IMAGERY IN CENTRAL NEW MEXICO, AND CONSIDERABLE MID AND HIGH LEVEL CLOUDINESS IN THE REGION OF UPWARD VERTICAL MOTION EAST OF THE TROUGH COVERED EASTERN NEW MEXICO AND THE TEXAS PANHANDLE. A MINOR TROUGH ROTATING AROUND THE GYRE CENTERED IN THE NORTHERN PLAINS EXTENDED FROM CENTRAL NEBRASKA INTO SOUTHEAST COLORADO AT 00Z, AND A REINFORCING SURGE OF COLD AIR IN THE LOWER LEVELS OF THE ATMOSPHERE WAS SPREADING ACROSS WESTERN KANSAS. THE LEADING EDGE OF THE COLD AIR ADVECTION EXTENDED FROM SOUTHEAST NEBRASKA TO THE CENTRAL OKLAHOMA PANHANDLE AT 04Z. AN INCREASE IN NORTHWEST WINDS AND RISING PRESSURES WAS EVIDENT BEHIND THE SUBTLE BOUNDARY. VERY RICH LOW LEVEL MOISTURE COVERED THE SOUTHERN PLAINS IN ADVANCE OF A DRYLINE IN WEST TEXAS, AND A WARM ELEVATED MIXED LAYER WAS EVIDENT IN THE MID LEVELS FROM WEST TEXAS TO THE UPPER MIDWEST. UPSTREAM IN THE PACIFIC, A DEEP OCCLUDED CYCLONE OVER THE ALEUTIAN ISLANDS NEAR 175W WAS FEEDING WARM AIR NORTH INTO AN UPPER LEVEL RIDGE NEAR 150W, AND A DOWNSTREAM TROUGH NEAR 130W WAS DIGGING TOWARD THE PACIFIC NORTHWEST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 207 AM CDT TUE MAY 21 2013 A PERIOD OF QUIESCENT WEATHER WILL PREVAIL IN WESTERN KANSAS THROUGH WEDNESDAY, AND TEMPERATURES WILL PROVIDE THE BIGGEST FORECAST CHALLENGE. CONSIDERABLE HIGH LEVEL CLOUDINESS WILL SPREAD NORTHWARD INTO SOUTHWEST KANSAS THIS MORNING AS THE VIGOROUS UPPER LEVEL TROUGH IN NEW MEXICO MOVES EAST INTO THE TEXAS PANHANDLE. THE HIGH CLOUDINESS WILL THIN THIS AFTERNOON AS THE TROUGH PROPAGATES EAST INTO CENTRAL OKLAHOMA. VERY COLD AIR ALOFT WILL PERSIST, AND AFTERNOON HEATING WILL SUPPORT DEVELOPMENT OF HIGH BASED CUMULUS CLOUDINESS AGAIN TODAY. COLD AIR ADVECTION BEHIND THE SUBTLE FRONTAL BOUNDARY WILL CONTINUE THIS MORNING, AND THE LOW LEVELS OF THE ATMOSPHERE WILL BE A LITTLE COOLER THAN YESTERDAY. TEMPERATURES AT H7 ARE CONTINUING TO COOL, AND MID LEVEL INSTABILITY WILL BE NEARLY ABSENT THIS AFTERNOON. AS A RESULT, THERE SHOULD BE FEW IF ANY HIGH BASED SHOWERS THIS AFTERNOON. A SUBTLE UPPER LEVEL TROUGH IN EASTERN UTAH WILL DROP INTO NEW MEXICO AND SOUTHEAST COLORADO THIS AFTERNOON, AND THE ENTRANCE REGION OF THE JET STREAK WITH THE MINOR TROUGH MAY PROVIDE SOME UPPER LEVEL DIVERGENCE IN SOUTHEAST COLORADO LATE IN THE DAY. MODEL SOUNDINGS TO HAVE SOME SLIGHT MID LEVEL INSTABILITY IN FAR SOUTHWEST KANSAS, AND A FEW VIRGA SHOWERS MAY SPREAD FROM COLORADO INTO MORTON COUNTY BEFORE DYING THIS EVENING. TEMPERATURES TODAY WILL BE SLIGHTLY COOLER THAN MONDAY AS A CONSEQUENCE OF THE INVASION OF COOLER AIR LATE MONDAY AND MONDAY NIGHT. WEAK HIGH PRESSURE WILL COVER WESTERN KANSAS TUESDAY NIGHT, AND WINDS WILL DIMINISH QUICKLY THIS EVENING AS THE BOUNDARY LAYER STABILIZES. DEWPOINTS IN THE 30S, MOSTLY CLEAR SKIES AND COLD AIR ALOFT WILL FAVOR STRONG RADIATIONAL COOLING, AND TEMPERATURES WILL DROP INTO THE 40S DURING THE NIGHTTIME HOURS. THE UPPER LEVEL ANTICYCLONE IN SASKATCHEWAN WILL BUILD INTO THE NORTHWEST TERRITORIES AS THE DEEP TROUGH NEAR 130W CLOSES OFF OVER THE PACIFIC NORTHWEST ON WEDNESDAY. A TROUGH ROTATING AROUND THE A LOBE OF THE POLAR VORTEX NORTHEAST OF HUDSON BAY WILL DIG SOUTH TO JAMES BAY WEDNESDAY, AND THE NORTHERN PLAINS UPPER LEVEL LOW WILL OPEN UP AND MOVE EAST WEDNESDAY AND THURSDAY. UPPER LEVEL RIDGING WILL BUILD OVER THE CENTRAL PLAINS WEDNESDAY, AND ANOTHER DAY OF MILD, QUIET WEATHER CAN BE EXPECTED IN WESTERN KANSAS. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 400 AM CDT TUE MAY 21 2013 MEDIUM RANGE MODELS INDICATE A WEAK UPPER LEVEL RIDGE OF HIGH PRESSURE MOVING EAST OUT OF THE ROCKIES INTO THE WESTERN HIGH PLAINS WEDNESDAY. ALONG WITH A GENERALLY WEAK FLOW ALOFT, FAIRLY DRY CONDITIONS CAN BE EXPECTED ACROSS WESTERN KANSAS THROUGH LATE WEDNESDAY AFTERNOON. HOWEVER, A FEW SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN A SOUTHEASTERLY UPSLOPE FLOW ACROSS EASTERN COLORADO WEDNESDAY AFTERNOON AS AN UPPER LEVEL JET CORE NOSES NORTHEAST ACROSS NEW MEXICO. AN ISOLATED THUNDERSTORM DRIFTING OFF THE FRONT RANGE INTO EXTREME SOUTHWESTERN KANSAS CANNOT BE RULED OUT WEDNESDAY EVENING. THE WEAK UPPER LEVEL RIDGE WILL DRIFT FURTHER EAST INTO THE CENTRAL PLAINS THURSDAY AS A STRONG CLOSED OFF LOW DROPS SOUTHEAST ACROSS THE PACIFIC NORTHWEST. THIS WILL OPEN MORE OF A SOUTHWESTERLY FLOW ALOFT ACROSS THE WESTERN HIGH PLAINS INCREASING DYNAMIC SUPPORT, INCLUDING INCREASING DIVERGENCE FIELDS. NEAR THE SURFACE, A BROAD AREA OF HIGH PRESSURE ACROSS THE UPPER MIDWEST WILL HELP INFLUENCE AN EASTERLY UPSLOPE FLOW ACROSS MUCH OF WESTERN KANSAS WHILE AN AREA OF LOW PRESSURE SETS UP ACROSS THE INTERMOUNTAIN WEST CREATING INCREASED LOW LEVEL CONVERGENCE ACROSS THE WESTERN HIGH PLAINS. AS PLENTY OF MOISTURE ADVECTS BACK INTO THE REGION WITHIN THE UPSLOPE FLOW, THE DEVELOPMENT OF THUNDERSTORMS WILL BE POSSIBLE, INCLUDING ACROSS PORTIONS OF WESTERN KANSAS. CHANCES FOR THUNDERSTORMS WILL CONTINUE EACH DAY FROM FRIDAY THROUGH THE WEEKEND AS THE UPPER LEVEL PATTERN VARIES LITTLE THROUGH THE END OF THE PERIOD. RATHER SEASONABLE TEMPERATURES ARE EXPECTED WEDNESDAY AS THE WEAK UPPER LEVEL RIDGING MOVES OF THE ROCKIES INTO THE WESTERN HIGH PLAINS. AN EASTERLY UPSLOPE FLOW WILL SET UP ACROSS THE WESTERN HIGH PLAINS AS SURFACE HIGH PRESSURE DRIFTS SLOWLY EAST ACROSS THE NORTHERN PLAINS. THIS WILL KEEP GENERALLY COOLER AIR IN PLACE WITH H85 TEMPERATURES RANGING FROM THE MID TEENS(C) ACROSS CENTRAL KANSAS TO THE LOWER 20S(C) ACROSS EXTREME SOUTHWEST KANSAS. LOOK FOR HIGHS UP INTO THE 70S(F) ACROSS CENTRAL KANSAS TO THE 80S(F) IN FAR SOUTHWEST KANSAS WEDNESDAY AFTERNOON. COOLER TEMPERATURES ARE EXPECTED THURSDAY AS THE SURFACE HIGH DROPS SOUTHEAST FROM THE NORTHERN PLAINS INTO THE UPPER MIDWEST USHERING SLIGHTLY COOLER AIR SOUTHWESTWARD INTO THE WESTERN HIGH PLAINS. HOWEVER, THIS BREAK WILL BE BRIEF AS WEAK UPPER LEVEL RIDGING RE-ESTABLISHES ACROSS THE CENTRAL PLAINS ALLOWING FOR A WARMING TREND LASTING THROUGH THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1254 PM CDT TUE MAY 21 2013 NORTHWEST WINDS WILL GRADUALLY DIMINISH THIS AFTERNOON TO 10 KTS BY 22Z AND THEN BECOME LIGHT NORTHERLY TONIGHT AS WEAK SURFACE HIGH PRESSURE MOVES INTO KANSAS. WITH THE LACK OF LOW LEVEL MOISTURE, VFR CONDITIONS WILL PERSIST. && .PRELIMINARY POINT TEMPS/POPS... DDC 77 45 81 52 / 10 0 0 10 GCK 74 44 82 52 / 10 0 0 20 EHA 76 49 84 55 / 10 10 20 20 LBL 78 47 84 54 / 10 10 10 20 HYS 72 44 76 51 / 10 0 0 10 P28 77 49 82 55 / 10 0 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...RUTHI SHORT TERM...RUTHI LONG TERM...JJOHNSON AVIATION...FINCH