Severe Thunderstorm Warning 146, NWS Topeka, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
249 PM CDT WED JUN 12 2002

THUNDER CHANCES TONIGHT AND WEEKEND...AND TEMPERATURES...MAIN
FORECAST CONCERNS.

UNSTABLE AIR STILL IN PLACE ACROSS THE CWA WITH LIS IN THE -5 TO -9
RANGE THIS AFTERNOON.  18Z SOUNDING SHOWED CAPES APPROACHING 3000
J/KG AND WEAKENING CAP.  DEW POINTS STILL IN THE UPPER 60S TO NEAR
70...SO ATMOSPHERE PRIMED FOR THUNDERSTORMS LATE THIS AFTERNOON AND
EVENING.  COLD FRONT/WIND SHIFT LINE WAS RUNNING FROM SOUTHEAST
NEBRASKA ACROSS THE NORTHWEST CWA AND INTO WESTERN KANSAS AT 19Z.
SOME CONVECTION WAS FIRING NEAR AND BEHIND BOUNDARY.  UPPER FLOW
CURRENTLY WEST TO EAST BUT SHOULD BECOME NORTHWEST-SOUTHEAST LATER
TONIGHT.  THIS NORTHWEST FLOW COMBINED WITH THUNDERSTORM OUTFLOW
SHOULD EASILY PUSH BOUNDARY THROUGH THE CWA BY THURSDAY MORNING.
MODELS ALSO FORECASTING MCS TO DEVELOP IN EASTERN CO/WESTERN KS
OVERNIGHT...THEN PROPAGATE SOUTHEAST.  WHILE THE BULK OF THIS IS
EXPECTED TO BE SOUTHWEST OF THE CWA...AM CONCERNED WITH WEST TO EAST
THERMAL GRADIENT BEING MORE DOMINANT THAN INFLOW COMPONENT.  WILL
HAVE AT LEAST CHANCE POPS OVER THE WHOLE CWA WITH FRONT MOVING INTO
UNSTABLE ENVIRONMENT...AND MAY HIT THINGS A LITTLE HARDER IN THE
SOUTHWEST NEARER EXPECTED MCS.

AFTER FRONT ROLES THROUGH...MILDER WEATHER IN STORE FOR THE NEXT
SEVERAL DAYS.  WILL KNOCK TEMPS DOWN A TAD FROM GOING FORECAST BASED
ON LATEST MOS NUMBERS AND NCEP GUIDANCE.

NEXT CHANCE FOR PRECIP COMES THIS WEEKEND AS NORTHWEST FLOW WAVES
TRACK THROUGH THE PLAINS.  TIMING OBVIOUSLY DIFFICULT THIS FAR
OUT...BUT A SERIES OF RIPPLES LOOKS LIKELY BEGINNING SATURDAY NIGHT
AND SUNDAY.  AVN SHUTS PRECIP OFF BY EARLY MONDAY MORNING...BUT EURO
MODELS HINT AT ANOTHER WAVE FOR MONDAY.  CURRENT FORECAST HAS
CHANCES IN SATURDAY NIGHT THROUGH MONDAY...AND SEE NO CLEAR REASON
TO CHANGE ANYTHING NOW.  DRY FORECAST FOR TUESDAY AND WEDNESDAY WITH
INCREASING TEMPERATURES UNDER BUILDING HEIGHTS ALOFT.

.TOP...NONE

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