ACUS01 KWNS 231958
SWODY1
SPC AC 231956
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0256 PM CDT SAT OCT 23 2010
VALID 232000Z - 241200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MO/MID MS VALLEYS
INTO THE SRN PLAINS...
...MID MO VALLEY TO UPPER MS VALLEY...
PARTS OF CENTRAL NEB AND SRN MN HAVE BEEN REMOVED FROM THE SLIGHT
RISK AREA WITH SEVERE PROBABILITIES LOWERED ACCORDINGLY. PERSISTENT
CLOUDINESS OVER CENTRAL NEB TO THE N-W OF THE SURFACE LOW HAS
LIMITED DESTABILIZATION THROUGH THE DAY...AND THUS A LOWER POTENTIAL
FOR A SEVERE WEATHER THREAT. MEANWHILE...MODERATE INSTABILITY
EXTENDING INTO SERN SD/FAR SWRN MN IS RESULTING IN AN ENVIRONMENT
SUPPORTIVE OF SUSTAINING ANY STORMS THAT MAY DEVELOP OVER ERN
NEB/WRN IA YET THIS AFTERNOON AND MOVE NWD/NEWD. SRN AND SERN MN
SEVERE THREATS APPEAR TO BE LOWER THAN INDICATED BY PREVIOUS
FORECASTS...WITH PART OF SERN MN BEING KEPT IN THE SLIGHT RISK AREA
AS 16Z WRF-HRRR AND 12Z WRF-NMM 4 KM SUGGEST STORMS THAT SHOULD
DEVELOP OVER IA THIS AFTERNOON/EVENING MAY REACH SERN MN PRIOR TO
WEAKENING INTO A MORE STABLE AIR MASS WITH NEWD EXTENT.
...NERN OK/NWRN AR/ERN KS/MO/SRN IA...
FORECAST REMAINS ON TRACK FROM NERN KS/NRN MO INTO SRN IA WHERE AIR
MASS HAS BECOME MODERATELY UNSTABLE AND EFFECTIVE BULK SHEAR RANGES
FROM 40-50 KT. APPARENT MCV PER SATELLITE IMAGERY...NOW TRACKING
NEWD THROUGH SWRN MO...MAY BE AIDING RECENT TSTM DEVELOPMENT TO THE
SOUTH OF KANSAS CITY. FOR ADDITIONAL MESOSCALE DETAILS FOR ERN KS
TO NRN MO...PLEASE SEE SPC MCD 1971.
15 PERCENT SEVERE WIND PROBABILITY AND 5 PERCENT TORNADO PROBABILITY
HAVE BEEN ADDED SWD FROM NRN MO/NERN KS TO NERN OK/NWRN AR. STORMS
DEVELOPING NNEWD INTO THIS REGION FROM ERN OK/WRN AR WILL POSE A
SEVERE WEATHER THREAT GIVEN INCREASING EFFECTIVE BULK SHEAR TO
AROUND 40 KT AND A MODERATELY UNSTABLE AIR MASS.
...OK/TX...
FORECAST REMAINS ON TRACK...WITH WRN EXTENT OF THE SLIGHT RISK AREA
BEING SHIFTED EWD GIVEN ONGOING CONVECTIVE TRENDS PER REGIONAL RADAR
AND SATELLITE DATA.
..PETERS.. 10/23/2010
.PREV DISCUSSION... /ISSUED 1118 AM CDT SAT OCT 23 2010/
...SRN PLAINS INTO OZARK PLATEAU...
SHORT WAVE TROUGH CURRENTLY PROGRESSING EWD THROUGH NM...FAR WRN TX
AND NWRN MEXICO WILL DEAMPLIFY THROUGH THE DAY ONE PERIOD WHILE
ACCELERATING NEWD THROUGH THE REGION INTO THE LOWER/MID MS VALLEY.
LOW-LEVEL MASS RESPONSE TO THIS IMPULSE WILL MAINTAIN A 30-40+ KT
SLY/SWLY LLJ FROM PORTIONS OF CNTRL/ERN TX INTO THE MID MS
VALLEY...EFFECTIVELY ENHANCING THE NWD FLUX OF A MOIST BOUNDARY
LAYER CHARACTERIZED BY DEW POINTS IN THE MID/UPPER 60S. WHILE
WIDESPREAD CLOUDINESS WILL TEMPER DAYTIME HEATING...THIS MOISTURE
COUPLED WITH STEEP MIDLEVEL LAPSE RATES WILL CONTRIBUTE TO A
MODERATELY UNSTABLE AIR MASS BY AFTERNOON WITH MLCAPE VALUES
APPROACHING 1000-2000 J/KG.
FORCING FOR ASCENT ATTENDANT TO MIDLEVEL TROUGH COUPLED WITH THE
DESTABILIZING WARM SECTOR SHOULD SUPPORT THE INTENSIFICATION OF
ONGOING QLCS TODAY FROM ERN OK SWD/SWWD INTO CNTRL TX. ADDITIONAL
MORE DISCRETE STORMS WILL BE POSSIBLE DOWNSTREAM WITHIN CONFLUENT
LOW-LEVEL REGIME OVER ERN TX. THE PRESENCE OF A 45-60 KT MIDLEVEL
JET STREAK ATTENDING SHORT WAVE TROUGH AND THE SUSTAINED BELT OF
STRONGER LOW-LEVEL FLOW /AS MENTIONED ABOVE/ WILL RESULT IN VERTICAL
SHEAR PROFILES SUPPORTIVE OF BOWING/LEWP AND SUPERCELL STRUCTURES
CAPABLE OF DAMAGING WINDS...HAIL AND A FEW TORNADOES. THIS SEVERE
WEATHER THREAT MAY DEVELOP EWD/NEWD INTO PARTS OF WRN AR AND SWRN MO
LATER TODAY INTO TONIGHT AS THE BOUNDARY LAYER CONTINUES TO
MOISTEN/DESTABILIZE IN ADVANCE OF EJECTING MIDLEVEL SYSTEM.
...MID/LOWER MO VALLEY...
CLOSED MIDLEVEL LOW OVER WRN PARTS OF NEB/SD WILL PROGRESS EWD
THROUGH THE MID MO VALLEY IN CONJUNCTION WITH ASSOCIATED SURFACE LOW
WHICH WILL DEVELOP FROM NWRN KS INTO ERN NEB BY THIS EVENING.
MORNING VISIBLE SATELLITE IMAGERY INDICATES CONSIDERABLE CLOUDINESS
OVER NEB/IA...WITH POTENTIAL FOR STRONGER DIABATIC HEATING OVER
PARTS OF KS INTO MO. THIS DIFFERENTIAL HEATING HAS RESULTED IN THE
DEVELOPMENT OF A WARM FRONTAL SEGMENT EXTENDING FROM NWRN KS EWD
THROUGH NWRN MO TO N OF STL.
STRENGTHENING SLY FLOW AHEAD OF THE DEEP-LAYER CYCLONE IS EXPECTED
TO ENHANCE THE FLUX OF A WARMER...MORE MOIST AIR MASS IN PLACE OVER
PARTS OF CNTRL/ERN KS/WRN MO NWD THROUGH THE MID MO VALLEY
TODAY...CONTRIBUTING TO AN AXIS OF MODERATE INSTABILITY /I.E. MLCAPE
VALUES OF 1000-2000 J PER KG/ BY AFTERNOON ALONG AND S OF
ABOVE-MENTIONED WARM FRONT. 12Z MODEL GUIDANCE SUGGESTS THAT
SURFACE-BASED STORMS WILL BECOME INCREASINGLY LIKELY BY MID/LATE
AFTERNOON FROM NE OF SURFACE LOW OVER NERN NEB/SERN SD/NWRN IA SWD
INTO NERN KS/NRN MO. GIVEN THE PRESENCE OF VERTICALLY-VEERING WIND
PROFILES WITH MODERATELY STRONG LOW AND DEEP-LAYER
SHEAR...ENVIRONMENT WILL BE SUPPORTIVE OF ORGANIZED STORM
MODES...INCLUDING SUPERCELLS IN LOCATIONS WHERE STRONGER
DESTABILIZATION CAN OCCUR. WHILE HAIL AND LOCALLY DAMAGING WIND
GUSTS WILL BE THE PRIMARY HAZARDS...ISOLATED TORNADOES WILL BE
POSSIBLE WITH ANY SUSTAINED...SURFACE-BASED SUPERCELLS.
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