DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1227 AM CDT TUE APR 30 2013

VALID 301200Z – 011200Z

…THERE IS A SLGT RISK OF SVR TSTMS FROM NRN KS INTO IA AND WI…

…SYNOPSIS…
A POTENT SHORTWAVE TROUGH WILL EJECT NEWD FROM THE NRN PLAINS INTO
ONTARIO DURING THE DAY WITH TRAILING BOUNDARY FROM WI INTO KS. SLY
LOW LEVEL FLOW AHEAD OF THIS BOUNDARY AND HEATING WILL LEAD TO
MODEST DESTABILIZATION…AND A RELATIVELY NARROW ZONE OF SEVERE
THUNDERSTORM THREAT IS EXPECTED BY LATE AFTERNOON.

ELSEWHERE…A WEAK UPPER LOW WILL AFFECT SERN TX AND LA WITH RAIN
AND STORMS…BUT MAINLY NON-SEVERE.

…NRN KS…SERN NEB…IA…WI…
A STALLED FRONT WILL EXTEND FROM WRN KS INTO CNTRL IA BY 00Z…AND
WILL PROVIDE A FOCUS FOR AFTERNOON AND EVENING STORM DEVELOPMENT DUE
TO CONVERGENCE AND STRONG HEATING. SHEAR PROFILES WILL BE MARGINALLY
SUPPORTIVE OF SUPERCELLS…BUT FLOW ORIENTATION RELATIVE TO THE
BOUNDARY SUGGESTS MERGERS WILL OCCUR. WITH STEEP LAPSE RATE PROFILES
LARGE HAIL AND LOCALLY DAMAGING WIND GUSTS WILL BE POSSIBLE. FORCING
ALONG THE BOUNDARY SHOULD REMAIN SUFFICIENT FOR BOUTS OF
THUNDERSTORMS THROUGH THE EVENING AND OVERNIGHT ESPECIALLY ACROSS
NEB AND NRN KS WITH A STRONG LOW LEVEL JET.