Severe Thunderstorm Warning 145, NWS Omaha, NE

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
220 PM CDT SUN JUN 22 2003

...UPDATED TO INCLUDE FLOOD WATCH...

FORECAST CHALLENGE IS SVR TSTMS TONIGHT AND INTO MON.

VERY MOIST AND UNSTABLE AIRMASS IS SITUATED ACROSS REGION THIS
AFTERNOON.  DAYTIME HEATING ACROSS MUCH OF THE AREA HAS BEEN
INHIBITED BY LEFT OVER CONVECTIVE CLOUD COVER AND IS KEEPING CAPE
VALUES IN THE 400-1400 J/KG RANGE.  SFC TROF EXTENDING FM SD INTO
WRN KS HAS A FEW DISTINCT LOWS ALONG IT.  18Z SFC ANALYSIS SHOWS ONE
LOCATED JUST W OF KLBF...WITH WRM FNT EXTENDING SEWD TO N CNTRL KS.
THIS BOUNDARY OF CONCERN FOR CONVECTIVE DEVELOPMENT OVER THE
AFTERNOON HOURS WITH DAYTIME HEATING ALLOWING CAPE VALUES TO BE
MUCH HIGHER.  SOME FLOODING POTENTIAL EXISTS ACROSS THE SRN HALF OF
THE CWA OVERNIGHT AS PWS OFF THE 18Z OAX AND TOP SOUNDINGS ARE 1.73
AND 2.09 RESPECTIVELY.  CORFIDI VECTORS SLOW DOWN DRAMATICALLY
AFTER 06Z AND LLJ STRENGTHENS TO 55-60 KTS AROUND SAME TIME FRAME.
ALL OF CWA IN MOD RISK...SEE SWODY1 FOR FURTHER DETAILS.

STILL APPEARS THAT STRONG CAP WILL BE IN PLACE ACROSS MUCH OF THE
FORECAST AREA DURING THE EARLY AFTERNOON ON MONDAY.  STORMS SHOULD
FIRE AGAIN LATE AFTERNOON...ESPECIALLY OVER NERN NEB NEAR BEST LOW
LEVEL CONVERGENCE AND LOWERING CONVECTIVE INHIBITION AREA.  NERN NEB
AND NWRN IA IN MOD RISK.

THUNDERSTORMS POSSIBLE AGAIN TUESDAY NIGHT AS UPPER TROF BEGINS TO
MOVE EAST SENDING SFC LO THRU CNTRL NEB. FNT THEN PUSHES THRU DURING
THE DAY WEDNESDAY SO HAVE CONTINUED CHANCE OF SHOWERS AND
THUNDERSTORMS THEN. NO MAJOR CHANGES HAVE BEEN MADE TO THE EXTENDED.

.OMA...FLOOD WATCH TNT SERN NEB AND FREMONT COUNTY IA.

GRIFFIS

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-231100-

HAZARDOUS WEATHER OUTLOOK...CORRECTION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
550 PM CDT SUN JUN 22 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PARTS OF EASTERN NEBRASKA
AND SOUTHWEST IOWA.

.DAY ONE...TONIGHT AND MONDAY

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER ALL OF
EASTERN NEBRASKA TONIGHT.   A TORNADO WATCH HAS BEEN ISSUED FOR
MUCH OF THE AREA.  SUPERCELLS ARE LIKELY TO DEVELOP EARLY THIS
EVENING OVER THE AREA WEST OF A LINE FROM NORFOLK TO LINCOLN.
THE PRIMARY WEATHER HAZARDS WILL BE VERY LARGE HAIL...DAMAGING
WINDS AND TORNADOES.  THE ATMOSPHERE IS VERY MOIST AND EXTREMELY
UNSTABLE.  AN UPPER LEVEL DISTURBANCE MOVING NORTHEAST OUT OF
EASTERN COLORADO AND WYOMING WILL HELP AID IN THUNDERSTORM
DEVELOPMENT OVER EASTERN NEBRASKA THIS EVENING AND THEN WILL MOVE
EAST INTO WESTERN IOWA DURING THE OVERNIGHT HOURS.

.DAYS TWO THROUGH SEVEN...MONDAY NIGHT THROUGH SUNDAY

THE CHANCE OF THUNDERSTORMS...SOME POSSIBLY SEVERE...WILL
CONTINUE MONDAY EVENING INTO TUESDAY AS VERY UNSTABLE AIR REMAINS
IN PLACE ACROSS THE REGION.  THERE WILL ALSO BE A CHANCE OF
THUNDERSTORMS ACROSS PARTS OF EASTERN NEBRASKA AND SOUTHWEST IOWA
WEDNESDAY THROUGH FRIDAY...HOWEVER IT IS TOO SOON TO DETERMINE
THE COVERAGE AND INTENSITY OF THESE THUNDERSTORMS AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTERS SHOULD BE ACTIVATED OR PREPARING TO ACTIVATE THIS
EVENING.  SPOTTERS ACTIVATION MAY BE REQUIRED ON MONDAY
AFTERNOON.

SMITH