Severe Thunderstorm Warning 218, NWS Omaha, NE

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
905 PM CDT THU JUL 25 2002

CURRENT WATER VAPOR IMAGERY AND THIS EVENINGS UPPER-AIR ANALYSIS
INDICATE A POTENT SHORTWAVE OVER WY, TRANSLATING EWD.  IN THE
LOW-LEVELS, 01Z SUBJECTIVE SURFACE ANALYSIS AND RUC DATA DEPICT A
VERY UNSTABLE AIRMASS JUST TO THE N OF A STATIONARY BOUNDARY THAT
STRETCHES ACROSS NRN KS INTO SRN IA.  ALTHOUGH THE 26/00Z OAX SHOWED
A CONSIDERABLE AMOUNT OF CIN STILL PRESENT, MOISTURE POOLING JUST
TO THE N OF THE BOUNDARY TO OUR S IS LIKELY RESULTING IN MORE CAPE
AND LESS CIN ACROSS OUR SRN ZONES.  OVER THE PAST HOUR THE
CONVECTIVE COMPLEX MOVING OUT OF WRN NEB HAS BEEN STRENGTHENING, AND
WE EXPECT THIS TREND TO CONTINUE AS IT ENCOUNTERS THE AXIS OF
MAXIMUM CAPE, CURRENTLY OVER S-CNTRL NEB.  CURRENT PROFILER DATA
FROM FBY INDICATES WEAK LOW-LEVEL WINDS WITH A MARGINAL AMOUNT OF
DEEP-LAYER SHEAR.  HOWEVER, WITH THE APPROACH OF THE WY SHORTWAVE,
WINDS SHOULD INCREASE THROUGHOUT THE ATMOSPHERE.  THUS, WOULDNT BE
SURPRISED TO SEE A SEVERE MCS MOVE THROUGH THE AREA OVERNIGHT.

CURRENT RADAR TRENDS INDICATE THAT THE CONVECTION IS MOVING EWD MORE
RAPIDLY THAN THE 25/18Z ETA AND 26/00Z RUC PROGS.  THUS, WE WILL
INCREASE THE LOWER END POPS ACROSS OUR CWFA.  OTHERWISE, ONLY SOME
MINOR CHANGES TO THE FORECAST ARE ANTICIPATED.

THE UPDATED ZONES WILL BE OUT SHORTLY.

MEAD

--415 PM CDT ISSUANCE--

FORECAST CONCERNS CONT AROUND PRECIP CHANCES AND TEMPS.

SYNOPSIS...REMNANT OUTFLOW BOUNDARY SEPARATES VERY HOT TEMPS IN
NORTHEAST KS FROM SOMEWHAT COOLER AIR IN ERN NEB.  APPEARS THAT
RIDGING ALOFT AHEAD OF STRONG SHORT WAVE EMERGING FROM WY HAS TENDED
TO KEEP THE LID ON CONVECTION.  SOMEWHAT DIRER AIR AT LOW LEVELS MAY
ALSO BE HELPING LID.

SHORT TERM...EXPECT WY SHORT WAVE TO SUPPORT EASTWARD PROPAGATING
MCS SIMILAR TO MODELS.  THIS WILL LIKELY REACH OUR AREA LATE
TONIGHT...WITH ONLY A SLIGHT CHANCE NEAR THE OLD OUTFLOW BOUNDARY
BEFORE THAT.  PRECIP WILL BE FADING AS IT GETS TO OUR AREA...BUT
WILL BE SUPPORTED BY MID LEVEL MOIST ADVECTION FOR A WHILE BEFORE
DYING OUT AND MOVING EAST IN THE MORNING.

THERE MAY BE TIME FOR THE ATMOSPHERE TO RELOAD CAPE BY LATE
AFTERNOON OR EVENING...FOR ANOTHER ROUND OF TSTMS FRI NIGHT.  UPPER
SUPPORT DOES NOT LOOK AT GOOD.

LATER PERIODS ARE GENERALLY A MESS OF WEAK WAVES EMERGING FROM
WESTERN TROUGH ALONG WITH SFC BOUNDARIES BOTH FRONTAL AND OUTFLOW.
JUST WENT FOR GENERAL TRENDS EXCEPT FOR SUGGESTIONS OF ANOTHER MCS
SUN NIGHT IN A COUPLE OF MODEL RUNS.  HOT IN THE SOUTH...BUT PROBABLY
NOT EXCEEDING ADVISORY CRITERIA IN A SUSTAINED WAY.

SITUATION CHANGES MONDAY AS WE GET INTO DRIER NW FLOW ALOFT.  COOLER
AND NO MENTION OF TSTMS MON NIGHT INTO THUR.

POLLACK
.OMA...NONE.

MEAD

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-261100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
520 PM CDT THU JUL 25 2002

STORM SPOTTERS MAY BE NEEDED OVER PORTIONS OF SOUTHEAST
NEBRASKA THIS EVENING...AND ACROSS ALL OF EASTERN NEBRASKA AND
SOUTHWEST IOWA LATE TONIGHT.

A STATIONARY FRONT WILL REMAIN IN PLACE FROM NORTHWEST KANSAS
INTO NORTHERN MISSOURI TONIGHT.  THE ATMOSPHERE IS QUITE UNSTABLE
IN THE VICINITY OF THE FRONT...AND THUNDERSTORM DEVELOPMENT IS
POSSIBLE THIS EVENING.	MODERATE AMOUNTS OF VERTICAL WIND SHEAR
SUGGEST THE POTENTIAL FOR SOME SEVERE STORMS...WITH LARGE HAIL
AND DAMAGING STRAIGHT LINE WINDS BEING THE PRIMARY HAZARDS.
LOCATIONS MOST LIKELY TO BE AFFECTED BY ANY SEVERE WEATHER ARE
SOUTH OF AN AUBURN TO FAIRBURY LINE.

ADDITIONAL THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS EVENING
OVER WESTERN NEBRASKA...AND THEN MOVE EAST ACROSS THE STATE
OVERNIGHT.  THESE STORMS WILL PROBABLY NOT MOVE INTO THE AREA
UNTIL AFTER MIDNIGHT.  DAMAGING STRAIGHT LINE WINDS...LARGE HAIL
AND LOCALIZED FLOODING WILL BE THE MAIN HAZARDS ASSOCIATED WITH
THESE THUNDERSTORMS.

UNSETTLED WEATHER IS LIKELY TO CONTINUE THROUGH THE WEEKEND...
AS A FRONT REMAINS DRAPED ACROSS THE CENTRAL PLAINS...AND A
SERIES OF UPPER DISTURBANCES MOVE EAST OUT OF THE ROCKIES.
THE GREATEST RISK OF SEVERE WEATHER WILL BE IN THE LATE
AFTERNOON AND OVERNIGHT HOURS...BOTH SATURDAY AND SUNDAY.

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).

MEAD