ZCZC SPCSWODY1 ALL COR
ACUS01 KWNS 122120
SPC AC 122118 COR...CORRECT GRAPHICS OVER SRN TX

STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK 
DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS.

VALID 122000Z - 131200Z

THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF SWRN OK AND NRN
TX TO THE RIGHT OF A LINE FROM 35 WSW SJT 55 NW ABI 35 NE CDS 10 E
CSM 45 ESE SPS 20 NNE DAL 45 S DAL 15 SE BWD 30 NW JCT 35 WSW SJT.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
25 S P07 55 E LBB 30 W CDS 30 N CVS 30 WNW TCC 35 SSE 4FC
45 WSW GCC 25 NE 81V 35 NW RAP 20 E LBF 20 S EMP 25 NNE TXK
20 WNW GPT 45 ENE CBM 10 SSE HSS 10 WSW BKW 35 S HLG 25 ENE LBE
10 NNE ABE 20 SW JFK ...CONT... 35 ENE CRE 45 S FLO 25 NE AGS
30 WSW MGR 35 SSE CEW ...CONT... 25 SSW BPT 10 SSE CLL 45 SE JCT
45 SE DRT.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 ESE CRP 45 E COT
65 SSE DRT ...CONT... 40 SSW P07 35 E PVW 20 N PVW 15 NE CVS
20 WNW LVS 50 WSW FMN 20 W U17 25 WNW CDC 45 W P38 60 S TPH
45 W BIH 10 WNW TVL 45 SSE 4LW 95 SSE BNO 30 N IDA 25 NNW FCA
50 ENE CTB 55 NNE BIL 25 SSE MLS 45 N REJ 25 W PIR 15 E FSD
55 NNE MOT 20 NNE RRT 85 NW CMX 30 NNW IWD 30 NNW RHI 30 SSW PIA
35 NNE EVV 30 WNW LUK 50 NNW MFD ...CONT... 15 WSW ART 15 SW GFL
25 NNE EWB.

...SRN PLAINS...
THE SRN STREAM OF A SPLIT UPPER FLOW REGIME WILL REMAIN THE MOST
ACTIVE FROM THE SRN PLAINS ENEWD TO THE MID-ATLANTIC STATES THROUGH
THE REST OF THE PERIOD.  STRONG SURFACE HEATING OVER WRN TX HAS
ALLOWED DRY LINE TO MIX EWD WITH THIS BOUNDARY EXPECTED TO EXTEND
FROM NEAR A CDS-SJT LINE BY LATE AFTERNOON.  NUMEROUS OUTFLOW
BOUNDARIES EXIST FROM SWRN OK/NRN TX SEWD INTO ERN TX FROM
PREVIOUS/ONGOING CONVECTIVE COMPLEXES.

CONVECTIVE COMPLEX OVER NRN TX CONTINUES TO BE SUPPORTED BY A 35 KT
SWLY LLJ INTO THE WRN PORTION OF THIS ACTIVITY.  18Z FWD SOUNDING
INDICATED A CAP BASED AROUND 800 MB WITH REGIONAL RADARS SHOWING
THE OUTFLOW IS MOVING WELL SOUTH OF THE STORMS.  THEREFORE...THIS
ACTIVITY SHOULD REMAIN ELEVATED AS IT CONTINUES TO MOVE SEWD THIS
AFTERNOON WITH HAIL BEING THE PRIMARY THREAT. 

MORE SIGNIFICANT CONVECTION IS EXPECTED TO DEVELOP LATE THIS
AFTERNOON AS WARM SECTOR FROM SWRN OK SEWD INTO ERN TX AND EAST OF
THE DRY LINE HAS BECOME VERY UNSTABLE TO EXTREME INSTABILITY WITH
MLCAPE RANGING FROM 2500-4000 J/KG.  VIS IMAGERY SHOWS CU/TCU
DEVELOPING ON THE WRN EXTENT OF THE NRN TX OUTFLOW BOUNDARY BETWEEN
ABI-SPS AND WITHIN THE AXIS OF STRONGEST INSTABILITY.  SUBSIDENCE
WITH SHORT WAVE RIDGING OVER THE DRY LINE APPEARS TO SUPPRESSING
CONVECTIVE DEVELOPMENT ATTM.  HOWEVER...CONTINUED SURFACE HEATING
COMBINED WITH INCREASING LARGE SCALE ASCENT WITHIN THE EXIT REGION
OF A 100 KT WLY UPPER JET SHOULD ALLOW ISOLATED STORMS TO DEVELOP
ALONG THE DRY LINE/ OUTFLOW BOUNDARIES OVER WRN TX BY LATE
AFTERNOON.  GIVEN A VERY UNSTABLE AIR MASS WITH 25-35 KT OF DEEP
LAYER SHEAR...STORMS WILL QUICKLY BECOME SEVERE WITH SUPERCELLS
PRODUCING LARGE HAIL... DAMAGING WINDS AND A FEW TORNADOES.  

STRENGTHENING SLY LLJ OVER CENTRAL-NRN TX AND INCREASING DEEP LAYER
OVER SWRN OK AND ALONG/E OF THE DRY LINE AROUND/JUST AFTER 00Z WILL
RESULT IN MORE NUMEROUS SUPERCELLS/CONVECTIVE CLUSTERS TO DEVELOP. 
OUTFLOWS FROM THESE STORMS WILL LIKELY CONGEAL INTO ONE OR MORE
COLD POOLS WITH 30-40 KT OF WLY MID-LEVEL FLOW AND EXTREME
INSTABILITY SUPPORTING A BOW ECHO OVERNIGHT NEAR BOUNDARY ACROSS
NRN TX.  WIDE SPREAD WIND DAMAGE WILL BE POSSIBLE WITH THIS BOW
ECHO. 

...SRN APPALACHIANS NEWD INTO THE MID ATLANTIC...
SURFACE BOUNDARY EXTENDS FROM SRN NEW ENGLAND WSWWD INTO THE OH
VALLEY WITH MODERATE TO A VERY UNSTABLE AIR MASS EXTENDING FROM SRN
PA/NJ SWD TO THE CAROLINAS.  UVVS WITH THE CLOSED UPPER LOW OVER
THE UPPER OH VALLEY WILL CONTINUE TO SPREAD ACROSS THE MID ATLANTIC
STATES THIS AFTERNOON/EARLY EVENING AIDING IN CONTINUED STRONG TO
SEVERE STORMS.  DAMAGING WINDS/HAIL WILL BE THE PRIMARY THREATS.

...ERN TX EWD TO CENTRAL GULF COAST STATES...
CONVECTIVE COMPLEX EXTENDING FROM CENTRAL LA INTO SERN TX WILL
CONTINUE TO MOVE ESEWD ALONG SURFACE BOUNDARY IN SRN LA THIS
AFTERNOON/EARLY EVENING.  30-35 KT OF DEEP LAYER SHEAR WILL SUPPORT
ORGANIZED STORMS WITH HAIL/DAMAGING WINDS REMAINING A THREAT.
HOWEVER...AS THE STORMS CONTINUE TO BECOME MORE ORIENTED PARALLEL
TO THE MEAN FLOW...A HEAVY RAIN THREAT WILL BE THE PRIMARY THREAT
INTO THE EVENING.

FURTHER EAST...FROM SERN MS INTO AL/GA...THUNDERSTORMS WILL
CONTINUE TO DEVELOP WITHIN A MODERATELY UNSTABLE AIR MASS. 
HOWEVER...GENERALLY WEAK DEEP LAYER SHEAR WILL FAVOR PULSE-TYPE
STORMS WITH MICROBURSTS BEING THE PRIMARY THREAT...GIVEN HIGH WET-
BULB ZERO HEIGHTS.

...WRN SD/CENTRAL HIGH PLAINS...
WV IMAGERY SHOWS A SHORT WAVE TROUGH MOVING EWD THROUGH WRN SD
EARLY THIS AFTERNOON AIDING IN CONVECTIVE DEVELOPMENT ACROSS THE
BLACK HILLS REGION.  WEAK INSTABILITY COMBINED WITH 30-35 KT OF
DEEP LAYER SHEAR BEING ENHANCED BY STRONGER FLOW ON THE SRN
PERIPHERY OF THE SHORT WAVE TROUGH WILL SUPPORT AN ISOLATED HAIL
THREAT...WITH LARGE SURFACE TEMPERATURE-DEWPOINT SPREADS ALSO
FAVORING ISOLATED DAMAGING WIND GUSTS.
 
FURTHER WEST...VIS IMAGERY SHOWS NUMEROUS THUNDERSTORMS OVER THE
HIGHER TERRAIN OF CO WITH ISOLATED CONVECTION NWD OVER WY.  25-30
KT OF WLY MID-LEVEL FLOW FROM WY INTO SD WILL SUPPORT A GREATER
POTENTIAL FOR ORGANIZED STORMS OVER THIS AREA WHERE OBJECTIVE
ANALYSES SHOW AN AXIS OF MODERATE INSTABILITY FROM ERN WY SEWD TO
WRN NEB/NWRN KS.

..PETERS.. 06/12/03

NNNN