CHASE PREDICTION CENTER

SIOUX FALLS, SD

CHASE OUTLOOK DAY 1

COD-046

0630Z MONDAY JUNE 17, 2002

VALID 12Z 06/17/02 THROUGH 06/18/02

THERE IS A SLIGHT RISK FOR SOUTHEAST SD...EASTERN NEB...PARTS OF IA...AND SOUTHWEST MN.

THERE IS ALSO A SLIGHT RISK FOR CHASEABLE THUNDERSTORMS OVER WESTERN NEB...WESTERN KS...EXTREME EASTERN CO...OK PANHANDLE AND THE TX PANHANDLE.

...WESTERN HIGH PLAINS...

A GENERAL NORTHWEST UPPER LEVEL FLOW PATTERN WILL CONTINUE THROUGH THE DAY ONE PERIOD. THIS WILL MAINTAIN LEE TROUGHING ACROSS THE WESTERN HIGH PLAINS FROM NEB SOUTH TO TX. LOW LEVEL SOUTHEAST FLOW AHEAD OF THE LEE TROUGH WILL CONTINUE TO BRING MODIFIED GULF MOISTURE TO THE REGION. WITH A DEEPLY MIXED BOUNDARY LAYER...AFTERNOON DEWPOINTS ARE EXPECTED TO REMAIN IN THE UPPER 50S. STRONG SOLAR INSOLATION WILL ALLOW FOR TEMPERATURES TO RISE WELL INTO THE 80S AND 90S ACROSS THE SLT RISK AREA. WITH DEWPOINTS IN THE 50S...THIS SHOULD YIELD A MLCAPE OF 1000-2000J/KG BY LATE AFTERNOON. AS MIXING CONTINUES THROUGH THE AFTERNOON...CONVECTIVE INHIBITION WILL CONTINUE TO DECREASE. THUNDERSTORMS WILL DEVELOP BY LATE AFTERNOON FROM NEB SOUTH TO THE TX PANHANDLE. DEEP LAYER SHEAR WILL BE MARGINAL FOR ORGANIZED SEVERE WEATHER...BUT SOUNDINGS INDICATE A STRONGLY VEERED PROFILE. THUS MULTI-CELLED CLUSTERS WILL LIKELY BE THE MAIN MODE OF CONVECTION. LARGE HAIL WILL CONTINUE TO BE THE MAIN THREAT WITH COOL MID LEVEL TEMPERATURES...BUT GIVEN THE DEEPLY MIXED LAYER...DAMAGING WIND WILL ALSO BE POSSIBLE.

...MISSOURI VALLEY...

SHOWERS/THUNDERSTORMS WILL LIKELY BE ONGOING ACROSS PARTS OF THIS REGION AT THE BEGINNING OF THE PERIOD. THIS ACTIVITY WILL QUICKLY WEAKEN TROUGH THE MORNING WITH LOSS OF LLJ. THIS ACTIVITY WILL LIKELY LEAVE AN OUTFLOW BOUNDARY TO FOCUS FURTHER SFC CONVERGENCE ALONG DURING THE AFTERNOON PERIOD. MOISTURE WILL CONTINUE TO INCREASE THROUGH THE DAY TO THIS REGION WITH A GOOD SOUTHERN LOW LEVEL FLOW. PERSISTENT SFC RIDGE AXIS ACROSS THE SOUTHERN PLAINS WILL INHIBIT TRUE TROPIC MOISTURE RETURN SO DEWPOINTS WILL GENERALLY REMAIN IN THE 50S. STEEP LAPSES ACROSS THIS REGION WILL CONTRIBUTE TO INCREASING INSTABILITY THROUGH THE AFTERNOON...WITH MLCAPE VALUES OF 1500-2500J/KG LIKELY. UNLIKE FARTHER WEST...MIXING WILL NOT BE NEARLY AS DEEP AS THUS MID LEVEL TEMPERATURE INVERSION IS LIKELY TO HOLD THROUGH THE AFTERNOON. THUNDERSTORMS ARE LIKELY TO DEVELOP THOUGH SHORTLY AFTER DARK AS STRONG LLJ OF 50KNTS INCREASE MASS CONVERGENCE ACROSS THE AREA. THIS ACTIVITY WILL BE RUTTED ABOVE THE BOUNDARY LAYER...AND THUS MAINLY POSE A LARGE HAIL POTENTIAL.

CHASE TARGET...NONE

BOUSTEAD