VORTEX STATUS MESSAGE AND FORECAST DISCUSSION NATIONAL SEVERE STORMS LABORATORY 1130 AM CDT APRIL 28 1995 OPERATIONAL STATUS AT 1100 CDT: TARGET AREA: n/a SUPPLEMENTAL SOUNDING/ARCHIVE II REQUESTS: LBB, AMA, MAF DAILY FORECAST DISCUSSION: Moderately strong (and increasing) mid- and upper-level westerlies across northwest Texas have resulted in about 90 degs. of shear from the sfc to 700 mb today. Dew points are on the low side, but increasing rapidly into the mid and upper 50s as a 30-40 kt southerly low-level jet continues. With 20+ deg. mid-lvl lapse rates, it appears that 2500 joules of CAPE is not unreasonable. Fairly large cap is a problem, but very warm air on and west of the dry line is progged by RUC and ETA models, so cap should break near the dry line. The strong temp gradient near the dry line should help in establishing aftn vertical circulations. Expectations are for shear to be too strong for instbility of most updraft candidates, but 1 or 2 should make it to t-storm stage - and probably become supercells. All of this should occur on the higher terrain. More widespread convection is expected later tonight and Saturday as next cool front overtakes dry line and pushes surface low se into central Texas by Saturday afternoon. Weakening shears and mid-level winds indicate decreasing supercell potential Saturday. PROBABILITIES OF OCCURRENCE IN VORTEX OPS AREA THRU 04Z (DAY1) AND 12-04Z (DAY2)... DAY1 DAY2 LIGHTNING 60 99 SEVERE 50 50 TORNADOES 20 10 TARGETABLE STORM 40 20 FCST STORM MOTION - TARGETABLE STORMS ONLY PRE-SUPERCELL 260/35 280/30 SUPERCELL 290/25 300/20 FCST INITIATION TIMES (LT) - TARGETABLE STORMS ONLY LIGHTNING 1700 on-going 1ST SEVERE RPT 1800 1500 1ST TORNADO 1830 1630 (low-chances) Moller