Severe Thunderstorm Warning 43, NWS Omaha, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
100 AM CDT WED APR 24 2002

FORECAST CHALLENGES -- SEVERE WEATHER POTENTIAL THIS MORNING AND
WINDS TODAY.

SYNOPSIS -- 24/00Z UPPER AIR DATA SHOWED LOW-LEVEL MOISTURE
RETURNING NWD INTO ERN NEB/WRN IA AHEAD OF STRONG COLD FRONT THAT
EXTENDED FROM NEAR HARTINGTON TO ELGIN, NEB AS OF 0545Z.  RUCII
OUTPUT SUGGESTS THAT MUCAPE VALUES HAVE INCREASED TO 1000-1500 J/KG
AHEAD OF THIS FRONT WITH DEEP-LAYERED SHEAR VALUES OF 20-22 M/S.
THE COMBINATION OF DCAPE VALUES OF 1000-1300 J/KG, LINEAR FORCING,
STRONG BOUNDARY-LAYER STORM-RELATIVE (S-R) INFLOW AND MARGINAL
MID-LEVEL S-R FLOW ALL SUGGEST THE POTENTIAL FOR A DAMAGING
WIND/LARGE HAIL EVENT.  THE ONLY POTENTIAL LIMITING FACTOR IS THE
AMOUNT OF CIN THAT THE RUC IS FORECASTING AHEAD OF THE FRONT
(200-400 J/KG).  THE QUESTION IS WHETHER THE STRONG ASCENT ALONG
THE FRONT CAN OVERCOME THIS AMOUNT OF CIN, AND IF SO, WHETHER THE
INTENSITY OF CONVECTION WILL BE LIMITED.

FORECAST -- ETA DIAGNOSTICS SUGGEST THE FRONT AND ASSOCIATED POSSIBLE
CONVECTIVE SYSTEM SHOULD BE TO OUR SE BY AFTERNOON.  CURRENT
METAR/MSAS OBJECTIVE ANALYSIS SHOW POST-FRONTAL 3-HR PRESSURE RISES
OF 7-9 MB OVER S-CNTRL SD/N-CNTRL NEB AND SHORT TERM ETA/RUCII WIND
FIELDS INDICATE A WIND ADVISORY WILL BE NECESSARY FOR THE ENTIRE
CWFA AT LEAST FOR THIS MORNING.  GUIDANCE TEMPERATURES NOT TOO BAD,
SO WILL GO CLOSE.

SURFACE RIDGE AXIS TO BUILD INTO CWFA OVERNIGHT AND THURSDAY WITH A
RAPID RETURN IN LOW-LEVEL MOISTURE THURSDAY NIGHT INTO FRIDAY.
GOING FORECAST HAS CHANCE POPS FRIDAY THROUGH SATURDAY AND THIS
LOOKS GOOD PER LATEST AVN OUTPUT.  MOST RECENT RUN OF AVN IS WARMER ON
BACKSIDE OF WEEKEND SYSTEM, SO WILL LEAVE A MENTION OF ANY RA/SN SN
OUT OF FORECAST ATTM.  IF TIME ALLOWS, WE WILL LOOK AT THE NEW MRF
WHEN IT ARRIVES AND MAKE ANY CHANGES TO THE EXTENDED IF NECESSARY.

IF YOU HAVE COMMENTS ON THE NEW FORECAST DISCUSSION FORMAT...PLEASE
E-MAIL THEM TO W-OAX.WEBMASTER@NOAA.GOV OR CALL DAVE THEOPHILUS AT
402 359-5166.

.OMA...WIND ADVISORY THIS MORNING ALL ZONES.

MEAD

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-241700-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
530 AM CDT WED APR 24 2002

STORM SPOTTER GROUPS IN EASTERN NEBRASKA AND SOUTHWEST IOWA WILL
NOT BE NEEDED TODAY OR TONIGHT.

A STRONG COLD FRONT...OVER FAR SOUTHEAST NEBRASKA EARLY THIS
MORNING...WILL MOVE SOUTH OF THE AREA BY AFTERNOON.  ALTHOUGH A
FEW MORNING THUNDERSTORMS ARE POSSIBLE ALONG THE FRONT...NO
SEVERE WEATHER IS EXPECTED.  BEHIND THE FRONT...WINDS WILL
INCREASE OUT OF THE NORTHWEST THIS MORNING TO 25 TO 35 MPH WITH
GUSTS TO 45 MPH.  AS A RESULT...A WIND ADVISORY IS IN EFFECT.
THE WINDS WILL DIMINISH BY AFTERNOON.

OVERNIGHT...BUILDING HIGH PRESSURE WILL BRING SEASONABLY COLD
TEMPERATURES TO EASTERN NEBRASKA AND SOUTHWEST IOWA...WITH A
FREEZE LIKELY NORTH OF A COLUMBUS TO FREMONT TO SHELBY IOWA LINE.

NO HAZARDOUS WEATHER IS EXPECTED THURSDAY AND FRIDAY.

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).

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