Severe Thunderstorm Warning 250, NWS Omaha, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
222 PM CDT FRI OCT 13 2000

MAIN FORECAST PROBLEM IS SHORT TERM CHANCE OF THUNDERSTORMS...A FEW
COULD BE SEVERE ACROSS SERN NE AND SWRN IA THIS EVENING.  ATTENTION
AFTER THAT TURNS TO TEMPERATURES AND THE CHANCE OF PCPN DEVELOPING
SATURDAY NIGHT/SUNDAY.  SURFACE ANALYSIS EARLY THIS AFTERNOON (19Z)
SHOWED CDFNT EXTENDING FROM LOW PRESSURE CENTER OVER SWRN MN ACROSS
ERN NE AND INTO CNTRL KS.  THERE APPEARED TO BE A WEAK TROF AHEAD
OF THE CDFNT.  CONVERGENCE WILL BE MAXIMIZED NEAR SURFACE TROF...
WITH HIGHEST DEWPOINTS IN THE MID 50S TO THE LOWER 60S.  POSITIVE
BUOYANT ENERGY OF AROUND 1000 J/KG SHOULD BE AVAILABLE.  MODIFIED
OAX SOUNDING FROM 12Z INDICATED VALUES NEAR 1500 POSSIBLE.  RISK
OF SEVERE IS MAINLY IN THE FORM OF HAIL...BUT FAIRLY STRONG SPEED
SHEAR ALSO FAVORABLE FOR SOME DAMAGING WINDS WITH STRONGEST CELLS
DUE TO ENTRAINMENT OF DRIER AIR ALOFT.  MAIN LIFT AND CHANCE OF
PCPN SHOULD EXIT MUCH OF THE AREA AFTER ABOUT 06Z...FAR SERN NE
AND SWRN IA APPEARS TO HAVE A CHANCE MUCH OF THE NIGHT.  SINCE A
WEAKER VORT MAX MOVES TOWARD NERN NE LATE...LEFT SOME SLIGHT
CHANCE IN FOR THE OVERNIGHT HOURS.

FOR SATURDAY THROUGH SUNDAY...CLOSED MID TROPOSPHERIC CIRCULATION
OVER THE ROCKIES OPENS UP AND FLOW BECOMES MORE ZONAL.  UPSTREAM...
TROF DEVELOPS OVER THE GULF OF AK AND THE ERN PACIFIC.  FRONT WILL
MAINLY BE SOUTH OR EAST OF THE AREA SATURDAY...AND CHANCE OF PCPN
SEEMS QUITE LOW.  EXPECT HIGHS FROM THE UPPER 60S TO MID 70S.  A
WEAK SHORTWAVE EJECTS EWD ACROSS NE SATURDAY NIGHT/EARLY SUNDAY.
CLOUDS SHOULD INCREASE AND WILL GO WITH 20/30 PERCENT CHANCE OF
MEASURABLE PCPN.  CLOUDINESS IS EXPECTED TO LINGER WITH EAST OR
NORTHEAST LOW LEVEL WINDS AND HIGHS FROM THE UPPER 50S TO MID 60S.
3 TO 5 DAY PERIOD LOOKS UNEVENTFUL.  FIRST DRAFT OF THE WORK ZONES
WAS SENT.

.OMA...NONE
MILLER

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-140600-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
435 PM CDT FRI OCT 13 2000

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

STORM SPOTTER ACTIVATION MAY BE REQUIRED IN SOUTHEAST NEBRASKA AND
SOUTHWEST IOWA THROUGH EARLY EVENING NEAR THE KANSAS AND MISSOURI
BORDER.

THUNDERSTORMS ARE POSSIBLE THIS EVENING EASTERN NEBRASKA AND
SOUTHWEST IOWA FROM AROUND NORFOLK AND TEKAMAH NEBRASKA AND ONAWA
IOWA SOUTH.  THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH
ABOUT 9 PM FROM AROUND LINCOLN AND NEBRASKA CITY NEBRASKA AND
SHENANDOAH IOWA SOUTH TO THE KANSAS AND MISSOURI BORDERS.

THE ATMOSPHERE IS UNSTABLE WITH DEW POINTS IN THE UPPER 50S AND
LOWER 60S AND TEMPERATURES IN THE UPPER 70S AND LOWER 80S.  A COLD
FRONT MOVING THROUGH FROM THE WEST WILL HELP TRIGGER THUNDERSTORMS.

THE COMBINATION OF INSTABILITY AND WIND SHEAR SUGGEST THAT A FEW
STORMS COULD PRODUCE HAIL AND OR STRONG WINDS.  THE THREAT OF SEVERE
WEATHER IS EXPECTED TO END BY AROUND 9 PM.

POWERS