DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0659 AM CST SAT MAR 27 2004 VALID 271300Z - 281200Z THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 20 WNW CDS 50 NE AMA 45 SE EHA 35 NNE EHA 35 WNW GCK 30 NNW GCK 15 SSW HLC 55 NE HLC 20 E GRI 35 NW OMA 35 W DSM 20 W IRK 40 NNW COU 35 NNE SGF 15 E FYV 10 NW PGO 20 ESE DUA 50 N FTW 30 SSE SPS 70 SSE CDS 45 S CDS 20 WNW CDS. THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 30 SSE MHE 40 W YKN 35 NE ANW 35 SSW PIR 50 SW JMS 40 ENE JMS 10 S FAR 40 N ATY 30 WSW BKX 30 SSE MHE. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 SE EWN 20 SSE GSP 30 NNE HOP MDH 15 N JBR 25 NNW ELD 40 NNE TYR 30 NW ACT 50 ENE JCT 45 SSW SJT 40 S BGS 50 S LBB 20 SSW AMA 45 NNW CAO 25 SW LHX 30 NNE LHX 35 WSW GLD 20 ENE AIA 45 N MOT ...CONT... 45 ENE ELO 25 ESE RHI 30 NE MTW 15 E MIE 30 NNE HGR 10 S JFK. ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL AND SRN PLAINS... ...THERE IS A SLGT RISK OF SVR TSTMS OVER A SMALL AREA OF THE NRN PLAINS... ...SYNOPSIS... HIGHLY AMPLIFIED MID/UPPER LEVEL FLOW WILL PERSIST ACROSS THE LOWER 48 STATES THIS PERIOD WITH THE MOST SIGNIFICANT FEATURE BEING A DEEP TROUGH EDGING EWD ACROSS THE GREAT PLAINS. SEVERAL VORT MAXIMA/SHORT WAVE TROUGHS WERE EMBEDDED WITHIN THE LARGER SCALE TROUGH AND LATEST WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA SUGGEST THE STRONGEST OF THESE IMPULSES WERE LOCATED OVER ERN MT...THE NRN GREAT BASIN... AND ERN NM/CO. STRONG DEEP LAYER MERIDIONAL FLOW ON ERN FLANK OF THE LARGE SCALE TROUGH HAS RESULTED IN AN EXTENSIVE WARM SECTOR OVER THE PLAINS STATES FROM TX TO SD. RECENT SURFACE ANALYSIS DEPICTED DEEPENING LEE-SIDE CYCLONE OVER ERN CO WITH AN INVERTED TROUGH AXIS EXTENDING NWD FROM WRN NEB INTO ND. PRIMARY SURFACE LOW ASSOCIATED WITH MT SHORTWAVE IS FCST TO DEVELOP ACROSS SD AND INTO MN THROUGH TONIGHT. MEANWHILE...THE CO LOW...ASSOCIATED WITH STRONG MID LEVEL IMPULSE EJECTING NEWD FROM NM/CO...WILL TRACK ACROSS KS/OK THROUGH TODAY AS A COLD FRONT SURGES SEWD OUT OF THE HIGH PLAINS IN ITS WAKE...AND DRYLINE SPREADS EWD FROM THE TX PNHDL TO WRN/CNTRL OK. ...KS/OK/WRN MO... DEEP CONVECTION HAS BEEN INCREASING STEADILY WITHIN BROAD PLUME OF ISENTROPIC LIFT AND INCREASING UPPER LEVEL DIFFLUENCE ACROSS ERN KS/NEB THIS MORNING AND THIS HAS BEEN WELL FCST BY SHORT TERM MODELS. ON THE OTHER HAND...STORMS FORMING ACROSS OK/TX PNHDLS AND CNTRL TX AHEAD OF NM/CO IMPULSE HAVE BEEN POORLY FCST BY MOST SHORT TERM MODELS AND THIS LENDS UNCERTAINTY TO SEVERE WEATHER FCST FOR TODAY. LATEST INDICATIONS SUGGEST THAT FORCING ASSOCIATED WITH MID LEVEL IMPULSE NOW SPREADING ACROSS WARM SECTOR FROM NM/CO MAY BE ARRIVING TOO EARLY FOR A MORE WIDESPREAD/SIGNIFICANT SEVERE WEATHER EPISODE. HOWEVER...ABUNDANT LOW LEVEL MOISTURE BENEATH WELL ESTABLISHED EML COUPLED WITH STRENGTHENING LARGE SCALE FORCING/HEIGHT FALLS WILL CONTRIBUTE TO INCREASINGLY FAVORABLE CONDITIONS FOR SCATTERED TO NUMEROUS SEVERE STORMS THROUGH THIS EVENING. AS CONVECTION ACROSS THE SRN PLAINS WARM SECTOR CONTINUES TO INCREASE INTO THIS AFTERNOON...POCKETS OF GREATER SURFACE-BASED INSTABILITY IN COMBINATION WITH MESOSCALE FORCING NEAR SURFACE LOW/DRYLINE/COLD FRONT SHOULD FAVOR A FEW LONGER-LIVED SUPERCELLS WITH LARGE HAIL/DAMAGING WIND AND TORNADO POTENTIAL. A FOCUSED AREA FAVORABLE FOR ROTATING STORMS COULD EVOLVE ACROSS NWRN AND CNTRL OK...AND PERHAPS INTO SRN KS LATER TODAY. ALTHOUGH POINT FCST DATA SUGGEST MESOSCALE AND STORM SCALE ENVIRONMENT THESE AREAS COULD SUPPORT A SIGNIFICANT REPORT OR TWO. HOWEVER... UNCERTAINTY ABOUT STORM COVERAGE...GIVEN STRONGEST FORCING WITH THE UPPER IMPULSE MAY BE PAST THE AREA...SUGGESTS HIGHER-END SLGT RISK PROBABILITIES ARE STILL WARRANTED. FURTHERMORE...IN THE WAKE OF MORNING/AFTERNOON STORMS ACROSS OK/KS...A SMALL WINDOW OF GREATER DESTABILIZATION SHOULD OCCUR AHEAD OF EWD SURGING COLD FRONT OVER WRN KS. ANY ONGOING/PREFRONTAL CELLULAR CONVECTION IS LIKELY TO BECOME INCREASINGLY LINEAR AS THE COLD FRONT SWEEPS EWD. A SEVERE SQUALL LINE SHOULD DEVELOP ON THE FRONT WITH HAIL AND WIND POTENTIAL INCREASING FROM CNTRL KS ESEWD ACROSS NRN OK...AND INTO NERN OK AND WRN MO AFTER DARK. ...NRN PLAINS... SEVERE HAIL AND PERHAPS A COUPLE OF STRONG WIND GUSTS MAY ACCOMPANY VIGOROUS CONVECTION DEVELOPING ACROSS THE REGION FROM NERN NEB...CNTRL SD AND SERN ND OVER THE NEXT FEW HOURS. RELATIVELY DEEP LOW LEVEL MOISTURE BENEATH STEEP MID LEVEL LAPSE RATES AND PERSISTENT FORCING FOR ASCENT AHEAD OF DEVELOPING SURFACE LOW SHOULD SUSTAIN A FEW STRONGER UPDRAFTS AND SOME POTENTIAL FOR HAIL. OVERALL STORM ORGANIZATION SHOULD BE LIMITED BY WEAK CLOUD BEARING SHEAR IN DEEP SLY FLOW...AND FCST OF GRADUALLY DIMINISHING INSTABILITY. ..CARBIN/JEWELL.. 03/27/2004