VORTEX STATUS MESSAGE AND FORECAST DISCUSSION NATIONAL SEVERE STORMS LABORATORY 1130 AM CDT THU MAY 4 1995 OPERATIONAL STATUS AT 1100 CDT: NO OPERATIONS TARGET AREA: N/A SUPPLEMENTAL SOUNDING/ARCHIVE II REQUESTS: NONE DAILY FORECAST DISCUSSION: WEAK AREA OF HIGH PRES ACRS THE SRN PLAINS IN WAKE OF SHRTWV TROF PRECLUDES OPS TDA. AMS OVER NRN SECTIONS TOO STABLE. ACRS EXTRM SRN PARTS OF THE OPS AREA SOME TSTMS ARE PSBL SINCE WEAK SFC BNDRY MAY SERVE AS A LOW LVL FOCUS IN REGION WHERE SOME INSTBY WILL REMAIN. HWVR DUE TO APCH OF UPSTRM RDG TEMPS ALF ARE ON THE RISE AND UPPER FLOW IS WEAKENING WHICH REDUCES THE CHC FOR SUPERCELLS. RDG ALF PASSES THE WRN PARTS OF THE AREA BY EARLY FRI AS DEEP TROF APCHS FROM THE W. RESULTANT SW FLOW ALF ACRS THE TX/OK PNHDLS AND FAR SW KS LEADS TO FVRBL SHEAR PROFILE FOR SUPERCELLS BY FRI EVE. LOW LVL MSTR WILL BE RETURNING ACRS W TX AND ERN NM FRI AS SFC TROF TAKES SHAPE OVER THE MTNS. APPEARS ANY DRYLN MAY REMAIN RATHER FAR TO THE W ON FRI WITH A GEN SELY FLOW ACRS THE PNHDLS. AS PER DICSUSSION AT VORTEX BRIEFING THERE MAY BE SOME PTNL FOR SUPERCELLS IN THE TX PNHDL ASSOCD WITH LOW LVL CNVGNC ALG HIGHER TRRN. AREAS TO THE S MAY REMAIN CAPPED. PRIND OPS ARE PSBL ACRS THE TK/OK PNHDLS AND EXTRM SW KS FRI AFTN DEPENDING ON WHERE STORMS ARE EXPCD TO INITIATE. AS SEEN YDA...FCSTG STM INITIATION IS PROVING TO BE A REAL CHALLENGE. LOOKING AHEAD...SAT ALSO OFFERS PSBL OPS ACRS W TX AS MID LVL HGTS CONT TO FALL WITH APCH OF NEXT SYS. A BETTER DRYLN SCENARIO MAY OCCUR ON SAT. RECENT HISTORY SUGS NO REASON NOT TO EXPECT CONTD PROGRESSION OF UPR SYSTEMS ACRS THE OPS AREA. PROBABILITIES OF OCCURRENCE IN VORTEX OPS AREA THRU 04Z (DAY1) AND 12-04Z (DAY2)... DAY1 DAY2 LIGHTNING 20 70 SEVERE 05 40 TORNADOES 00 20 TARGETABLE STORM 00 20 FCST STORM MOTION - TARGETABLE STORMS ONLY PRE-SUPERCELL ----- 230/35 SUPERCELL ----- 250/25 FCST INITIATION TIMES (LT) - TARGETABLE STORMS ONLY LIGHTNING ----- 1600 1ST SEVERE RPT ----- 1800 1ST TORNADO ----- 1900