Severe Thunderstorm Warning 249, NWS Omaha, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
400 AM CDT MON AUG 12 2002...UPDATE

WITH AM PACKAGE...WILL ALLOW FLOOD WATCH TO EXPIRE.  CONSIDERING
EVOLUTION OF PRECIP OVR THE LAST COUPLE OF HRS...EXPECT SOME SHOWER
AND THUNDERSTORM REDEVELOPMENT OVER NORTHEAST NEBRASKA THIS
MORNING...WITH HEAVY RAIN MORE LIKELY FARTHER SOUTH AND HEAVIER
RAINS IN NE NEB WOULD BE MORE LOCALIZED.

...

155 AM CDT MON AUG 12 2002 DISCUSSION

FORECAST CHALLENGES...HEAVY RAIN/SVR POTENTIAL OVERNIGHT...TSRA
TODAY INTO TUE...TEMPS.

SYNOPSIS...NWS WSR-88DS SHOWING SEVERAL ACTIVE AREAS OF CONVECTION
AS UNSEASONABLY STG CLOSED LOW WITH 80 M HGT FALLS AND  H3 100KT JET
ASSOCIATED WITH IT ADVANCES INTO THE PLNS.  MAIN CONVECTIVE COMPLEX
WITH DECENT BOWING AND DAMAGING WINDS MOVING THRU FSDS AREA
INTO NW IA.  THE 04Z FSD MTR HAD A PK WND OF 67KTS.  THE LATEST SFC
ANALYSIS HAD THE SFC LOW OVR SE SD...WITH A CDFNT INTO CNTRL AND SW
NEB.  STORMS DEVELOPED ALONG THE DRY LINE IN LBF AND GLDS AREA SUN
AFT AND IS PUSHING INT GIDS AREA.  A ROGUE SUPERCELL NR AURORA
PRODUCED BASEBALL SIZE HAIL EARLIER IN THE EVENING NR HALSEY.

FORECAST...IN VERY SHORT TERM...WILL MONITOR CONVECTION FOR SEVERE
AND FLASH FLOOD THREAT.  FFG VALUES BELOW AN INCH AT KNOX AND CEDAR
COUNTIES.  INITIAL THINKING WILL BE TO CONTINUE FLOOD WATCH TODAY
WITH LOW FFG VALUES.  CONVECTION HAS HAD A TOUGH TIME MAKING IT INTO
THE OAX CWA AS IT WILL HAVE TO ERODE HOT AIR IN PLACE. NELIGH
PROFILER HAD LOW LEVEL JET AT 50KT AT 05Z...UP FM 40KT AT 04Z.  PER
SOUNDING/SVR PARAMETER ANALYSIS...DAMAGING WNDS AND LARGE HAIL THE
PRIMARY THREAT MOST AREAS WITH ANY HEAVY RAINS A PROBLEM IN THE
WATCH AREA.

THE UPR LO IS NOT COMING OUT CLEANLY AND WILL LINGER PRECIP
INTO TUE AM IN THE SE ZONES. AS WITH PREVIOUS UPR LO...DIVERGENT
PATTERN TAKES MAIN ENERGY ACROSS THE NRN PLNS WITH SECONDARY AREA
SPLITTING OFF OVR KS...THIS HAS RESULTED IN MUCH OF THE FCST AREA
RELATIVELY DRY WITH STORMS TO THE NORTH AND SOUTH.  SHORT RANGE
MODELS SHOWING SOME SLIGHT TIMING DIFFERENCES WITH THE AVN SLOWER
AND HAS A STRONGER LOBE OF ENERGY SWINGING THROUGH SD/NEB TAF/EVE.

WILL CONTINUE LIKELY POPS IN ZONES TODAY AND CHC POPS TON.  HAVE
POPS IN SE GROUPS ONLY TUES.  TEMP FCST TO TAKE INTO CONSIDERATION
FNT/CLDS/PRECIP.  HAVE UPR 70S TO MID 80 MOST ZONES TOD AND 70S TO
AROUND 80 FOR TUE.  COOL DOWN IS SHORT LIVED AS WAA RETURNS WED AM
WITH STG WAA THU.

IN LATER PERIODS...HAVE SLG CHC PRECIP WITH A RIPPLE FRI AM AND CHC
POPS SAT/SUN WITH NEXT SHORT WAVE TROF.  WILL HAVE TO LOOK AT NEW
MODELS AS THEY COME IN THIS AM.

.OMA...NONE.

ZAPOTOCNY

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-122300-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1256 PM CDT MON AUG 12 2002

STORM SPOTTER ACTIVATION MAY BE NEEDED IN SOUTHEAST NEBRASKA
AND SOUTHWEST IOWA LATE THIS AFTERNOON OR EARLY TONIGHT.

A COLD FRONT FROM ONAWA IOWA TO SEWARD WILL MOVE SLOWLY
SOUTHEAST THIS AFTERNOON.  THUNDERSTORMS ARE EXPECTED TO
DEVELOP IN THE INCREASINGLY WARM AND UNSTABLE AIR AHEAD OF
THE FRONT.  WIND SHEAR WILL BE FAVORABLE FOR SUPERCELL
DEVELOPMENT...SO SOME OF THE STORMS COULD BECOME SEVERE.
HAIL AND DAMAGING WINDS WILL BE THE PRIMARY HAZARDS.

INSTABILITY WILL DECREASE ACROSS THE REGION LATER TONIGHT AS
THE COLD FRONT PUSHES THROUGH THE ENTIRE AREA.	SCATTERED
THUNDERSTORMS ARE EXPECTED TO CONTINUE FOR A WHILE TO THE
NORTH OF THE FRONT...BUT WITHOUT ENOUGH INSTABILITY TO
CAUSE SEVERE WEATHER.

A FEW SHOWERS MAY LINGER INTO TUESDAY MORNING IN SOUTHEAST
NEBRASKA AND FAR SOUTHWEST IOWA.  OTHERWISE...DAY AND
STABLE CONDITIONS WILL PREVAIL THROUGH WEDNESDAY AS HIGH
PRESSURE AND COOLER TEMPERATURES COVER THE AREA.

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC AND CLIMATIC
INFORMATION IS AVAILABLE ON THE INTERNET AT
WWW.CRH.NOAA.GOV/OAX OR AT WEATHER.GOV (LOWER CASE).

POLLACK

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-122300-

HAZARDOUS WEATHER OUTLOOK ... CORRECTION LAST PARAGRAPH
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1256 PM CDT MON AUG 12 2002

STORM SPOTTER ACTIVATION MAY BE NEEDED IN SOUTHEAST NEBRASKA
AND SOUTHWEST IOWA LATE THIS AFTERNOON OR EARLY TONIGHT.

A COLD FRONT FROM ONAWA IOWA TO SEWARD WILL MOVE SLOWLY
SOUTHEAST THIS AFTERNOON.  THUNDERSTORMS ARE EXPECTED TO
DEVELOP IN THE INCREASINGLY WARM AND UNSTABLE AIR AHEAD OF
THE FRONT.  WIND SHEAR WILL BE FAVORABLE FOR SUPERCELL
DEVELOPMENT...SO SOME OF THE STORMS COULD BECOME SEVERE.
HAIL AND DAMAGING WINDS WILL BE THE PRIMARY HAZARDS.

INSTABILITY WILL DECREASE ACROSS THE REGION LATER TONIGHT
AS THE COLD FRONT PUSHES THROUGH THE ENTIRE AREA. SCATTERED
THUNDERSTORMS ARE EXPECTED TO CONTINUE FOR A WHILE TO THE
NORTH OF THE FRONT...BUT WITHOUT ENOUGH INSTABILITY TO
CAUSE SEVERE WEATHER.

A FEW SHOWERS MAY LINGER INTO TUESDAY MORNING IN SOUTHEAST
NEBRASKA AND FAR SOUTHWEST IOWA.  OTHERWISE...DRY AND
STABLE CONDITIONS WILL PREVAIL THROUGH WEDNESDAY AS HIGH
PRESSURE AND COOLER TEMPERATURES COVER THE AREA.

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC AND CLIMATIC
INFORMATION IS AVAILABLE ON THE INTERNET AT
WWW.CRH.NOAA.GOV/OAX OR AT WEATHER.GOV (LOWER CASE).

POLLACK