Flash Flooding and Flood in Nebraska, September 10 to 12, 2003

SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
229 PM CDT WED SEP 10 2003

SFC MAP THIS AFTN MUCH LIKE YDA. INTENSE SFC LOW CNTR OVR WRN SD
W/TRAILING COLD FNT INTO NE CO AND SECONDARY WV IN REFLECTION OF
STG UPR TROF CROSSING DIVIDE ATTM. MID LVL DRY SLOT OVERTOPPING CWA
IN WAKE OF MORNING SW MOVING INTO MN ATTM.

FOREMOST SHRT TERM CONCERN CONTS W/SVR CONVN CHCS LT THIS AFTN AND
FIRST HALF OF TONIGHT. TOR WATCH COMING SHORTLY. DESTABILIZATION
GREATLY HAMPERED SO FAR TKS TO GRUNGE SC CLD LYR BUT ERODING QUICKLY
ESP SW IN BTWN JET STREAKS. EMERGING JET STREAK EMANATING FM SE CO
AND DVLPG ACCAS FIELD NR KDEN/KAKR A SIGN OF THINGS TO COME. LACK OF
INHIBITION AND INCREASING LG SCALE UVV/S SHLD KEEP DISCRETE SUPERCELL
WINDOW SHRT W/PRIMARY EVENT TIED TO SURGING COLD FRONT AND LIKELY LG
LINEAR SEGMENT ALG IT. COULD BE QUITE A WIND EVENT AND NOT DOUBT A
TOR THREAT GIVEN MAGNITUDE OF SHEAR/LOW LFC/S AND DEEP BL MSTR. 0-1KM
BTR ATTM OVR ERN NE BUT SUSPECT LL FLW TO REALLY BACK AS CO WV AND
ASSOCD JET STREAK DUMBBELL OUT LTR THIS AFTN. AS SUCH...CAT POPS IN
ORDER OVERNIGHT.

FOR THU...HOLD OVER RISK OF MORE RAIN INVOF OF MID LVL TROF AND
KEPT POPS IN MOST OF DAY ACRS CWA...HWVR CLRG XPCD LT AS SYS PINCHES
SWD INTO SRN PLAINS AND LG SCALE SUBSIDENCE OVERSPREADS CWA BEHIND
CO WV. EWD EXTENT OF CLRG LINE BIT TRICKY ON FRI AS UPR LOW CLOSES
OFF OVR TX PANHANDLE WHICH MAY HAVE AN IMPACT ON MAX TEMPS SE CWA
AND MORE SO ON SAT. CONTINUITY HERE LACKING AS UPSTREAM KICKER
DROPPING OUT OF SW CANADA NOW MUCH SLWR. GLARING CONSENSUS AT THIS
POINT IS TO KEEP UPR SYS STACKED TO OUR SW WHICH WOULD WRAP AT LEAST
MID LVL MSTR BACK INTO AREA AND WARRANT A SLGT POP IN ADV OF
SECONDARY COLD FRONT THEN. SLIP IN TIMING NECESSITATES SOME
ADJUSTMENT IN TEMPS SAT BUT OTHERWISE COOLING TREND ON TRACK THROUGH
SUN.

.GID...NONE.

T

KSZ005>007-017>019-NEZ039>041-046>049-060>064-072>077-082>087-111200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HASTINGS NE
1200 PM CDT WED SEP 10 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL NEBRASKA AND
PARTS OF NORTH CENTRAL KANSAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH CENTRAL
NEBRASKA AND NORTH CENTRAL KANSAS THROUGH TONIGHT. ISOLATED SHOWERS
AND THUNDERSTORMS WILL CONTINUE THIS AFTERNOON MAINLY EAST OF HIGHWAY
281 AS AN UPPER LEVEL DISTURBANCE MOVES INTO NORTHEASTERN NEBRASKA.
THIS AFTERNOON AND EVENING...THUNDERSTORMS WILL REDEVELOP AREA
WIDE NEAR A PRE FRONTAL TROUGH THAT RUNS FROM SOUTH CENTRAL SOUTH
DAKOTA...THROUGH CENTRAL NEBRASKA...AND INTO CENTRAL KANSAS. WARM
MOIST SURFACE AIR STREAMING INTO THE EASTERN HALF OF KANSAS AND
NEBRASKA...TOGETHER WITH STRONG UPPER LEVEL WIND SHEAR WILL HELP
SUPPORT STRONG TO SEVERE STORMS ACROSS THE OUTLOOK AREA...ESPECIALLY
EAST OF HIGHWAY 183...WITH LARGE HAIL...STRONG DAMAGING WINDS...AND
ISOLATED TORNADOES A POSSIBILITY THROUGH 9 PM. THE AREA WITH THE
GREATEST TORNADO THREAT WILL LIE TO THE NORTH OF INTERSTATE 80 AND
EAST OF HIGHWAY 281.

LATER THIS EVENING AND OVERNIGHT...MULTIPLE STORMS WILL GROUP
TOGETHER INTO A LINE OF STORMS...MOVING WITH OR JUST AHEAD OF A
COLD FRONT THAT WILL PUSH THROUGH THE REGION OUT OF NORTHWESTERN
NEBRASKA. THESE STORMS WILL LIKELY BRING PERIODS OF HEAVY RAIN...
LARGE HAIL AND STRONG DAMAGING WINDS AS THEY MOVE EASTWARD THROUGH
THE FORECAST AREA OVERNIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THUNDERSTORMS WILL LINGER ALONG THE COLD FRONTAL BOUNDARY THURSDAY...
MAINLY EAST OF HIGHWAY 14...HOWEVER CHANCES DIMINISH BEHIND THE FRONT
BY THURSDAY AFTERNOON. DRY AND COOL WEATHER IS FORECAST THROUGH THE
WEEKEND...BEFORE A SLOW WARMING TREND NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTERS MAY BE NEEDED LATER THIS AFTERNOON AND EVENING...
AND SHOULD BE PREPARED FOR RAPID DEPLOYMENT IF SEVERE APPROACHES
THEIR AREA.

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