957 
FXUS63 KTOP 030709
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE  TOPEKA KS
210 AM CDT THU JUN 3 1999

...PROBLEMS ARE MORNING CONVECTION...AND WHETHER CONVECTION TONIGHT 
TO THE NORTH WILL SLIDE OVER NORTHEAST PORTION OF AREA...

EXPECT JET MAX AND WARM AIR ADVECTION HELPING DRIVE THE CONVECTION 
TO CONTINUE SPREADING ACTIVITY TO THE EAST/NORTHEAST.  LOCATION OF 
THIS MORNINGS THUNDERSTORMS AT FORECAST TIME WILL IMPACT EXACT ZONE 
WORDING.  INTEND TO HAVE CATEGORICAL POPS IN THE EASTCENTRAL WITH 
CHANCE POPS EXTREME NORTHEAST.  (NEED FOR POPS IN NORTHCENTRAL WILL 
DEPEND ON EASTWARD TRANSLATION BEFORE ZFP TIME).

SURFACE BOUNDARY IS EXPECTED TO LIFT NORTHEAST THROUGH MOST OF THE 
FORECAST AREA BY AFTERNOON.  AFTER PASSAGE...SUFFICIENT LOW LAYER RH 
WILL BE LEFT TO SUPPORT CU MUCH OF THE DAY.  30+ KNOT 850MB WINDS 
AND TIGHTENING SURFACE GRADIENT WILL PRODUCE BREEZY CONDITIONS FOR 
NORTHCENTRAL COUNTIES TODAY (SLIGHTLY LESS IN THE EAST).

CONVECTION CONTAMINATED AIR BEGINS A GOOD WARMING BY EVENING WITH 
20-22C 850MC AIR IN PLACE THROUGH FRIDAY.

MAIN CONCERN FOR TONIGHT IS WHETHER THUNDERSTORM DEVELOPMENT IN 
CENTRAL/EASTERN NEBRASKA WILL TAIL SOUTHWARD INTO NORTHEAST KANSAS 
LATE TONIGHT/FRIDAY MORNING WHERE PRECIPITABLE WATER VALUES APPROACH 
1.5 INCHES AND CAPES OF 2000+...OR...WHETHER CAP BE STRONG ENOUGH.

FORECAST ITEMS...SOUTHEAST SURFACE WINDS SHOULD KEEP READINGS 
IN LINE WITH FAN GUIDANCE TODAY AND TONIGHT.  SOUTH/SOUTHWEST WINDS 
ON FRIDAY WILL PUSH READINGS NEAR FWC/FAN GUIDANCE.  WILL INCLUDE 
30% LATE NIGHT AND 40% EARLY MORNING POPS ALONG AND NORTHEAST OF 
MARYSVILLE...HOLTON...VALLEY FALLS LINE IN THE NORTHEAST WITH 30% 
EARLY MORNING IN NEXT TIER OF COUNTIES.


ROGERS

.TOP...NONE.