SWODY1
SPC AC 301226
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0726 AM CDT MON AUG 30 2010
VALID 301300Z - 311200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE NRN/CNTRL PLNS INTO
THE UPR MS VLY...
...SYNOPSIS...
AMPLIFIED WRN TROUGH/ERN RIDGE PATTERN WILL CONTINUE THIS PERIOD AS
POTENT SHORTWAVE IMPULSE NOW OVER UT EJECTS NE ACROSS THE CNTRL
RCKYS INTO THE NRN PLNS...AND UPSTREAM JET STREAK NOW OFF THE ORE
CST CONTINUES ESE TO THE NRN GRT BASIN. APPROACH OF UT DISTURBANCE
SHOULD SUPPORT INTENSIFICATION OF EXISTING SFC WAVE ALONG STALLED
FRONT OVER SD/NW NEB TODAY. THE WAVE SHOULD MOVE NEWD ALONG THE
BOUNDARY INTO ERN ND BY EVE...BEFORE CONTINUING NE WITH FURTHER
DEEPENING OVER SE MB/WRN ONT EARLY TUE. IN THE WAKE OF THE
LOW...TRAILING COLD FRONT EXPECTED TO ACCELERATE SEWD... OVERTAKING
PREFRONTAL TROUGH NOW OVER THE CNTRL HI PLNS.
...NRN/CNTRL PLNS TO UPR MS VLY TODAY/TONIGHT...
PERIODIC EPISODES OF ELEVATED TSTMS...SOME OF WHICH COULD YIELD SVR
HAIL...EXPECTED TODAY ALONG/N OF AFOREMENTIONED SFC FRONT OVER THE
NRN PLNS. THE HAIL RISK SHOULD BE GREATEST FROM NERN WY AND SE MT
INTO WRN/NRN ND. THIS THREAT MAY INCREASE DURING THE AFTN AS ASCENT
STRENGTHENS WITH APPROACH OF UT UPR VORT.
BY LATE AFTN/EARLY EVE...A MORE APPRECIABLE SVR RISK SHOULD EVOLVE
FROM ERN ND S/SW INTO CNTRL/ERN SD AND PARTS OF NEB AS COMBINATION
OF SFC HEATING AND INCREASING LARGE SCALE ASCENT FOSTER SFC-BASED
STORM DEVELOPMENT INVOF DEEPENING SFC LOW...AND ALONG LEE
TROUGH/COLD FRONT. DEVELOPMENT ALSO MAY BE AIDED BY NNEWD
ACCELERATION OF MID LVL IMPULSE/MOISTURE MAX NOW IN SRN CO.
40-50 KT SSWLY MID TROPOSPHERIC FLOW...INCREASING MOISTURE /PW
1.50-1.75 INCHES/...AND FAVORABLE JUXTAPOSITION OF VERTICAL
SHEAR/BUOYANCY LIKELY WILL YIELD A SEVERAL HOUR WINDOW FOR
SUPPORTIVE OF SEMI-DISCRETE SUPERCELLS POSING A RISK FOR LARGE HAIL
AND TORNADOES. THE TORNADO THREAT WOULD APPEAR TO BE GREATEST OVER
THE ERN DAKOTAS...NE OF DEEPENING SFC LOW. HOWEVER...GIVEN
LIKELIHOOD FOR STORM INITIATION NOT ONLY NEAR SFC WAVE...BUT ALSO
SWD ALONG ACCELERATING COLD FRONT/PREFRONTAL TROUGH INTO
NEB...TORNADO THREAT IN THIS CASE WILL BE ESPECIALLY DEPENDENT ON
STORM SCALE EVOLUTION/INTERACTIONS THAT CANNOT BE ACCURATELY
FORECAST THIS FAR IN ADVANCE. AT ANY RATE...GIVEN STRENGTH OF 700
MB FLOW...STRENGTHENING OF LLJ TOWARD/AFTER DARK...AND COINCIDENT
ARRIVAL OF RICHER LOW LVL MOISTURE FROM IA...SITUATION BEARS WATCH
FOR AT LEAST AN ISOLD TORNADO THREAT CONTINUING NEWD INTO WRN MN
AFTER SUNSET...DESPITE LIKELY EVOLUTION OF STORMS INTO ONE OR MORE
BROKEN QLCSS BY THAT TIME.
DMGG WINDS SHOULD BECOME THE MAIN CONCERN LATER THIS EVE AS THE
CONVECTIVE SYSTEMS AND THEIR EMBEDDED BOWING SEGMENTS CONTINUE
MAINLY NE ACROSS ERN SD AND MN. REGENERATIVE/BACKBUILDING STORMS
MAY PERSIST THROUGH EARLY TUE ALONG WRN EDGE OF LLJ IN ERN NEB/WRN
IA.
...SRN HI PLNS THIS AFTN/EVE...
A MORE ISOLD SVR THREAT...POSED BY SCTD MULTICELL CLUSTERS CAPABLE
OF DOWNBURSTS AND PERHAPS A SPOT OR TWO OF HAIL...MAY EVOLVE THIS
AFTN/EVE FARTHER S ALONG NNE/SSW LEE TROUGH FROM WRN KS SSW INTO THE
OK/TX PANHANDLES...W TX...AND ERN NM. THIS REGION WILL REMAIN
REMOVED FROM STRONGEST ASCENT/MID LVL COOLING ASSOCIATED WITH UT
SHORTWAVE TROUGH. BUT DEEPLY MIXED BOUNDARY LAYER/STEEP LOW LVL
LAPSE RATES...MODERATE MOISTURE...AND 25-35 KT DEEP SSWLY FLOW
SUGGEST POTENTIAL FOR ISOLD SVR WIND GUSTS THROUGH ABOUT MID EVE.
..CORFIDI/ROGERS.. 08/30/2010
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