Severe Thunderstorm Warning 211, NWS Topeka, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
305 PM CDT MON SEP 28 1998

...MAIN FORECAST PROBLEM IS THUNDERSTORMS CHANCES...

AS OF 19Z SURFACE CAPE VALUES WERE RUNNING AROUND 3000 J/KG WITH CIN
VALUES OF -20 TO -60 J/KG.  THIS WOULD SUGGEST ANY CAP ACROSS THE AREA
WAS ERODING.  ADAP PUTS BEST MOISTURE CONVERGENCE ACROSS NORTHERN
KANSAS.  ETA AND NGM SHOW SHORT WAVE OVER NORTHWEST NEBRASKA MOVING
SOUTHEAST INTO NORTHERN MISSOURI BY TUESDAY MORNING.  VISUAL
SATELLITE LOOPS SHOW CUMULUS DEVELOPING IN CONVERGENCE ZONE OVER
NORTH CENTRAL KANSAS.  FOR TONIGHT WILL GO WITH CHANCE POPS FOR
AREAS NORTH INTERSTATE 70 AS WAVE ERODES ANY REMAINING CAP.

FOR LATER PERIODS...PREFER THE ETA MODEL.  IT APPEARS TO BEST HANDLE
THE MOVEMENT OF THE UPPER LOW AND THE CANADIAN SURFACE HIGH BY 48
HOURS.

ETA SHOWS A STRONG SHORT WAVE EJECTING OUT OF THE WESTERN US UPPER
LOW INTO NORTH CENTRAL KANSAS BY 06Z WEDNESDAY.  850-700 MB
Q-VECTORS SHOW IMPRESSIVE LIFT AHEAD OF THIS WAVE LATE TUESDAY
AFTERNOON INTO TUESDAY NIGHT.  WOULD EXPECT THE AIRMASS TO BECOME
QUITE UNSTABLE AHEAD OF THE WAVE WITH CAPE VALUES EXCEEDING 3000
J/KG.  COULD SEE A FEW SEVERE THUNDERSTORMS AS FORECAST SOUNDINGS
SHOW A DECENT AMOUNT OF SHEAR.  CONVECTION SHOULD GEL INTO AN MCS
TUESDAY NIGHT OVER NORTHEAST KANSAS.  COULD MORE FLOODING IF MCS
DEVELOPS...LATER SHIFTS MAY NEED TO ISSUE A FLASH FLOOD WATCH.

MAX TEMPERATURE FORECAST TO BE VERY DIFFICULT ON WEDNESDAY AS
COMBINATION CLOUDS...PRECIPITATION AND APPROACHING CANADIAN TO PLAY
HAVOC WITH HIGHS.

NGM/FWC GUIDANCE LOOKS BETTER THAN COOLER FAN/AVN NUMBER FOR
TEMPERATURES THROUGH TUESDAY NIGHT...WITH BELOW GUIDANCE
TEMPERATURES FORECAST ON WEDNESDAY.

.TOP...NONE.

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