VORTEX STATUS MESSAGE AND FORECAST DISCUSSION NATIONAL SEVERE STORMS LABORATORY 1130 AM CDT SUN APRIL 9 1995 OPERATIONAL STATUS AT 1100 CDT: GO TARGET AREA: SW OK, N CNTRL TX SUPPLEMENTAL SOUNDING/ARCHIVE II REQUESTS: 18/21Z SNDGS REQUESTED FM ALL VORTEX RAOB SITES TDA; ALL SITES ALSO ON STANDBY FOR SUPPLEMENTAL SNDGS MON. WE REQUEST AVBL ARCHIVE II BE ACTIVATED AT ALL 88D SITES INVOF TARGET AREA. DAILY FORECAST DISCUSSION: NOT AN EASY ONE. CDFNT CONTS DRIVING S THRU CNTRL OK INTO N CNTRL TX WITH DRYLN TRPL PT VCNTY RED RVR W OF SPS. EXPC FNT TO SLOW THIS AFTN AS LEAD SFC WAVE CRNTLY SERN KS WKNS AND PRES FALLS DVLP FRTHR W IN RESPONSE TO DIGG SYS OVR RCKYS. 12Z UA DATA AND LTST RUC SUGGEST SYS WL DIG MORE STGLY THAN INDCD BY PROGS. THIS COMPLICATES TIMING ISSUE FOR TDA, AS PRES FALLS MAY BE SLOWER TO SPRD EWD INTO HI PLAINS. WE EXPC PRES FALLS TO BEGIN BACKING LL FLOW BY LATE AFTN, HOWVR, WITH DRYLN AND ASSOCD TRPL PT RMNG IN SAME GENL AREA THRU EARLY EVE. TWO MESOSCALE SCENARIOS BEING CONSDRD. ONE IS DVLPMT NR TRPL PT AS DIURNAL HTG WKNS STG CAP ENUF FOR LL CONVGC TO INITIATE CONVCTN. AVBL CAPE NR 3000 BY MAX HTG INDCS POTL FOR RPD DVLPMT IF CAP BRKS, WITH STMS MOVG/ DVLPG NEWD ALG QSTNRY FNT. ADDL DVLPMT ALSO PSBL SWD ALG DRYLN INTO NRN TX. OTR SCENARIO IS DVLPMT ALG FNT FRTHR W OVR SRN TX PNHDL OR S PLAINS AREA. MSTR WL BE NEG FACTOR THERE, BUT WE CUD SEE ENUF LL MSTR BHD FNT TO DESTBLZ AMS IN REGION WHERE CAP WL BE WKR. ARMADA WL HEAD TWD RED RVR AREA OF SW OK NRN TX INITIALLY TO BE IN POSN FOR ANY OF THESE SCENARIOS. DUE TO DELAY OF UPR DYNAMICS AND MID-LVL COOLING, WE EXPC A LATE SHOW. LTL TIME TO EXAMINE DAY2 CLOSELY, BUT WITH WRN TROF EXPCD TO DIG STGR THAN PROGGED, DYNAMIC FORCING MAY CONT INTO MON AND MAINTAIN A RISK OF SVR FRTHR W THAN EARLIER EXPCD, INCLDG ERN PTNS OF VORTEX AREA. BUT SNC IT ALSO INCRSS POTL FOR DVLPMT OVNGT, DAY2 MAY BE GUNGED IF WDSPRD CONVCTN FIRES OVR AREA TNGT. BRANICK/BURGESS PROBABILITIES OF OCCURRENCE IN VORTEX OPS AREA THRU 04Z (DAY1) AND 12-04Z (DAY2)... DAY1 DAY2 LIGHTNING 70 90 SEVERE 60 60 TORNADOES 30 30 TARGETABLE STORM 40 30 FCST STORM MOTION - TARGETABLE STORMS ONLY PRE-SUPERCELL 23035 22045 SUPERCELL 26025 25035 FCST INITIATION TIMES (LT) - TARGETABLE STORMS ONLY LIGHTNING 1800L 1300L 1ST SEVERE RPT 1845L 1330L 1ST TORNADO 1930L 1415L