Severe Thunderstorm Warning 99, NWS Omaha, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
255 PM CDT MON JUN 19 2000

A MOIST AND UNSTABLE AIR MASS NOW IN PLACE ACROSS REGION PROVIDING
INGREDIENTS FOR TSTMS. APPEARS TO BE TWO SEPERATE DISTURBANCES IN
UPPER FLOW WILL PROVIDE UVV TO INITIATE AND SUSTAIN TSTMS TNGT INTO
TUE. FIRST EXTENDING FROM NE WY INTO ERN CO EJECTING OUT OF MAJOR
UPPER TROF ACROSS NRN RCKYS. THIS FEATURE WILL LIKELY AID IN
GENERATION OF TSTMS ALONG SFC TROF/DRY LINE WITHIN NEXT FEW HOURS.
TSTMS WILL LIKELY CONTINUE EAST THROUGH THE NIGHT INTO TUE INTO
EASTERN NEB AND WRN IA AS SFC TROF AND COLD FRONT MOVES EAST AND
INTERACTS WITH MOIST AND UNSTABLE AIR MASS PUMPED BY LOW LEVEL JET.
FEW OF THESE STORMS TNGT COULD BE SEVERE PER DAY 1 OUTLOOK.  SECOND
DISTURBANCE EXTENDS FROM WRN KS INTO TX PNHDL LIFTING NEWD. THIS
FEATURE INTERACTING WITH A MORE SUBTROPICAL TYPE AIR MASS WITH
EXTENSIVE MID AND LOW LEVEL MOISTURE GENERATING SHOWERS AND EMBEDDED
TSTMS ACROSS ERN KS AND WRN MO WHICH MAY WORK INTO PTNS SE NEB ANND
SW IA TNGT.

ON TUE CDFNT JUST CLEAR NERN NEB DURING MRNG HOURS. THESE REGION MAY
SEE SOME SHOWERS LINGER INTO AFTN BUT GENERALLY TREND TO A DRIER AND
MORE STABLE AIR MASS DURING DAY. REST OF AREA IN VICINITY AND AHEAD
OF FNT STILL APPEAR TO HAVE GOOD POTENTIAL FOR SHWRS AND TSTMS TUE
AS MAJOR UPPER TROF MOVES INTO AREA PROVIDING UVV ALONG WITH COOLING
MID LEVEL TEMPS. BASED ON CAPE...AND TOTAL TOTALS AREA FROM SW IA
INTO SE NEB MAY HAVE SEVERE RISK. SHOWERS AND THUNDERSTORMS TO END
THIS AREA DURING EVE AS FRONT AND UPPER FORICING MOVE AWAY.. ATTM
BASED ON LAPSE RATES AND STABILITY INDICES RISK OF INSTABILITY
SHOWE`RS WED WITH AFTN INSOLATION APPEARS SMALL.

.OMA...NONE.
WIESE

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-201000-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
613 PM CDT MON JUN 19 2000

...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA...

STORM SPOTTER ACTIVATION MAY BE NECESSARY TONIGHT IN AREAS OF
EASTERN NEBRASKA AND SOUTHWEST IOWA.

MOIST AND UNSTABLE AIR COVER MUCH OF EASTERN NEBRASKA AND SOUTHWEST
IOWA.  STRONG SOUTH WINDS CONTINUE TO ALLOW THE NORTHWARD TRANSPORT
OF MOISTURE TONIGHT.  AN AREA OF SEVERE THUNDERSTORMS HAS BEEN
OCCURRING OVER CENTRAL NEBRASKA.  THIS ACTIVITY IS BEING DRIVEN BY
AN UPPER LEVEL DISTURBANCE.  THESE STORMS MAY BEGIN ENTERING
NORTHEAST NEBRASKA AFTER 8 PM AND SPREAD SOUTHEAST ACROSS THE REST
OF THE AREA DURING THE REMAINDER OF THE NIGHT.

WINDSHEAR PROFILES INDICATE THAT A FEW OF THESE STORMS MAY BECOME
SUPERCELLS.  WITH THE DEEP MOISTURE AVAILABLE...SOME SUPERCELLS MAY
BE OF THE HIGH PRECIPITATION TYPE.  MANY OF THESE STORMS WILL ALSO
BE HEAVY RAIN PRODUCERS THAT MAY PRODUCE FLASH FLOODING.

B SMITH