VORTEX STATUS MESSAGE AND FORECAST DISCUSSION NATIONAL SEVERE STORMS LABORATORY 1145 AM CDT APRIL 21 1995 OPERATIONAL STATUS AT 1100 CDT: standby til 1 pm TARGET AREA: southeast ok and northeast tx SUPPLEMENTAL SOUNDING/ARCHIVE II REQUESTS: maf, fwd, shv, crp at 18z DAILY FORECAST DISCUSSION: perplexing situation today...one which both the models and the human fcstrs are having difficulty with. once again very strong winds aloft exist acrs ok and n tx...with a chance of very high helicities where easterly or sely winds hold in the vicinity of bndries. one such bndry is the stnry fnt acrs se and s cntrl ok. low-lvl mstr is incrsg rpdly alg the lwr tx coastal plains nwd into the aus/sat area. dew pts were incrsg alg the upr tx coast...but they started to mix out at 16z. thus...nwd trajectories into n cntrl tx/se ok offer deeper mstr. this mstr should race north under a stg cap in s tx, where chcs for thunder appear to be extremely low next 6-10 hrs. there may be enough mstr conv and lift for a few tstms nr the fnt by 00z...but little help is expected from main short wave which wl continue to intensify and dig a bit tdy. thus...main show should be late in coming...prbly after 04z. however should 1 or 2 storms go up by 00z they should quickly bcm svr...spcly should advancing mstr bcm juxtaposed with low-lvl forcing and blo an area of 20+ mid-lvl lapse rates (which have been slowly expanding nwd from s tx since 00z last ngt). PROBABILITIES OF OCCURRENCE IN VORTEX OPS AREA THRU 04Z (DAY1) AND 12-04Z (DAY2)... DAY1 DAY2 LIGHTNING 40 70 SEVERE 20 50 TORNADOES 10 10 TARGETABLE STORM 20 20 FCST STORM MOTION - TARGETABLE STORMS ONLY PRE-SUPERCELL 2340 2240 SUPERCELL 2735 2535 FCST INITIATION TIMES (LT) - TARGETABLE STORMS ONLY LIGHTNING 1600 0630 1ST SEVERE RPT 1800 0630 1ST TORNADO 1900 0630