Tornadoes and Hail in Nebraska, April 18, 2003

SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
230 PM CDT FRI APR 18 2003

AS THOUGHT YESTERDAY...FIRST SHORTWAVE THROUGH AND FIRST BATCH OF
CONVECTION INTO OMA AREA...AND NEXT...SFC AND UPR WAVE WEST OF
OFFICE WITH 1MB PR PRESSURE DROPS AND LOW LOOKING TO MOVE OVR NRN
HALF OF CWA. NOTHING ELSE HAS REALLY CHANGED MUCH...WITH MID 50 DPTS
SHOWING ACROSS KANSAS COUNTIES WITH DRY PUSH WEST OF COUNTIES MOVING
THIS WAY. SUNSHINE INFILTRATING SWRN PORTION OF FA WITH SFC TEMPS
INTO 60S OVR KS AREA. EXCELLENT LL INSTABILITY WITH =8
LAPSE...HOWEVER MID LVL RATES FALL OFF SOMEWHAT. CONVECTION STARTING
JUST WEST OF PHILLIPS AND ROOKS COUNTIES WITH NEW BATCH OF SHOWERS
STARTING UP IN LBFS ERN PORTION. STORM MOTION NNE NRN HALF AND ENE
SRN HALF. CLOUDS OVR NRN TWO THIRDS OF FA KEEPING LID ON THINGS
ELSEWHERE. HUGE LL SHEAR MOVING INTO CWA WITH EXTREMELY STRONG LL
ASCENT GOING ON. LL MOISTURE TRYING TO RETURN RAPIDLY INTO AREAS
FROM SSE AHEAD OF LOW. DRY AIR ALREADY MOVING INTO HLC AS THIS IS
WRITTEN. EXPECTING NEW BATCH OF TSRW TO START AND RIDE ACROSS NRN
CWA...ROUGHLY N OF I 80 THROUGH MID EVE...WITH STRONGER CONVECTION
OCCURRING AS TEMPS RISE WITH SUNSHINE SERN AND ERN ZONES. BEST CHC
FOR SEVERE ACTION LOOKS TO BE MOSTLY E AND SE OF FA...HOWEVER
COMBINATION OF INGREDIENTS...ESPECIALLY STRONG BOUNDARY LAYER SHEAR
WILL PUT CHANCE FOR ROUGH ACTION INITIATING FROM MITCHELL AND JEWELL
COUNTIES IN KS...UP THROUGH THAYER FILLMORE AND YORK COUNTIES IN NE.
WOULD SAY THAT MAIN THREAT WILL BE FROM HAIL TO AN INCH AND POSSIBLE
STRONG WIND WITH LCL RISING QUICKLY TO 4000 FT OR SO. ALSO POSSIBLE
ISO TOR CHANCES WITH EARLY STRONG CONVECTION AND SMALL SUPERCELL
FORMATION WHERE MOISTURE IS MORE PLENTIFUL...BUT AGAIN PROBABLY E
OR SE OF FA. OTHERWISE SHARP LINE OF STORMS LOOK TO LIGHT UP FROM S
TO N AND MAY CATCH OUR FAR ERN ZONES BEFORE RIDING INTO OMA AND TOP
AREA. SHOULD BE RATHER BRIEF SEVERE POTENTIAL FOR US HOWEVER...IF AT
ALL. OTHERWISE...MOST OF CWA EXCEPT FOR SWRN PORTION SHOULD HAVE
DECENT CHC FOR SHOWERS AND THUNDER...WITH BEST CHC FOR ACTUAL WATER
OVR NRN QUARTER.

NEXT WEEK AS WHOLE CONTINUES TO LOOK ACTIVE. PUT CHC FOR SERN HALF
CWA FOR LATER IN DAY SAT WITH TROUGH AXIS CONTINUING TO PULL OVR
REGION...AND EXTREMELY VOLATILE SITUATION SETTING SOUTH OF OUR
AREA...INTO SRN KS AND OK. CONVECTION LIKELY TO RIDE RIGHT UP AND
INTO AT LEAST SERN PORTION OF FA. ANOTHER CHC FOR SUN AFTERNOON EVE
WITH SHORTWAVE ENERGY MOVING IN OVR NERN ZONES AROUND BACKSIDE OF
TROUGH. THROUGH REST OF EXTENDED...NO REAL CHANGES OTHER THAN
STARTING CHANCES FOR PRECIP TUE WITH MORE SHORTWAVE ENERGY RIDING
OVERHEAD...BUT LIKELY ELEVATED PRECIP ONLY.

.GID...NONE.

10

KSZ005>007-017>019-NEZ039>041-046>049-060>064-072>077-082>087-191200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HASTINGS NE
1159 AM CDT FRI APR 18 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL NEBRASKA AND
PARTS OF NORTH CENTRAL KANSAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A SURFACE LOW PRESSURE SYSTEM SITUATED IN SOUTHWEST NEBRASKA AT NOON
WILL MOVE EAST ACROSS THE STATE DURING THE AFTERNOON AND INTO THE
EVENING. THUNDERSTORMS MAY DEVELOP TO THE EAST AND SOUTHEAST OF THIS
LOW.  EXTENSIVE CLOUD COVER WILL HELP LIMIT INSTABILITY EARLY THIS
AFTERNOON...HOWEVER DRIER AIR WILL MOVE IN FROM THE SOUTHWEST
RESULTING IN SOME CLEARING SKIES AS THE AFTERNOON WEARS ON.

WIND SHEAR IN THE ATMOSPHERE WILL BE CONDUCIVE FOR SUPERCELL
DEVELOPMENT THIS AFTERNOON AND EVENING...BUT AVAILABLE LOW LEVEL
MOISTURE WILL BE BETTER IN THE EASTERN PARTS OF NEBRASKA AND KANSAS.

STORM DEVELOPMENT IS POSSIBLE AFTER 3 PM...AND SOME OF THESE
STORMS COULD BECOME SEVERE...WITH LARGE HAIL BEING THE PRIMARY
SEVERE HAZARD. HAIL THE SIZE OF GOLFBALLS IS POSSIBLE MAINLY OVER
AREAS EAST OF HIGHWAY 281.  MINI SUPERCELL TORNADOES ARE POSSIBLE AS
WELL...ALTHOUGH THAT THREAT LOOKS TO BE FURTHER TO THE EAST OF THE
LISTENING AREA.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTER ACTIVATION MAY BE REQUIRED THIS AFTERNOON AND THIS
EVENING...MAINLY FOR AREAS ALONG AND EAST OF ROUTE 281.

EWALD