Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jan 11 2024 06:00:21 ACUS01 KWNS 110600 SWODY1 SPC AC 110558 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1158 PM CST Wed Jan 10 2024 Valid 111200Z - 121200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE ARK-LA-TEX... ....SUMMARY... Severe thunderstorms, associated with tornadoes, wind damage and isolated large hail, are likely to develop across parts of the Ark-La-Tex this evening into the overnight. A severe threat is also expected to develop further south across parts of east Texas and Louisiana. ....Ark-La-Tex... An impressive upper-level system will translate quickly eastward through the Desert Southwest today, reaching the southern Plains this evening. Within the base of the trough, a 100 to 120 knot mid-level jet will move through west Texas this evening, as the nose of the jet overspreads the Ark-La-Tex. Ahead of the system, moisture will return northward across east Texas and Louisiana, with the nose of the moist sector reaching southern Arkansas by early evening. In response, a pocket of instability is forecast to develop across southeast Oklahoma, southwest Arkansas and northeast Texas, where convective initiation is expected during the mid evening. Thunderstorms are likely to rapidly increase in coverage during the late evening. Most hi-resolution models develop a line of strong to severe storms and move the line slowly eastward across southwest Arkansas and far northeast Texas during the early overnight period. As lift and shear increase due to the approach the mid-level jet, conditions are expected to become favorable for severe storms. Model forecast soundings across the Ark-La-Tex by 06Z have surface dewpoints near 60 F as far north as the Louisiana and Arkansas state line. Even so, MLCAPE should reach the 500 to 1000 J/kg range at the northern edge of the moist sector by late evening. Very strong lift associated with the exit region of the mid-level jet combined with low LCL heights and strong low-level shear should be favorable for supercells embedded in the line, and with the more discrete cells that develop ahead of the line. Some forecast soundings suggest that 700-500 mb lapse rates will approach 8 C/km across the northern part of the warm sector. Although the large-hail threat should remain isolated, the steep mid-level lapse rates should be sufficient for a significant-hail threat. Hailstones of greater than 2 inches in diameter will be possible a few hours after cells initiation, as the storms mature. In addition, 0-3 km storm-relative helicity is forecast to peak near 400 m2/s2 in and just north of the Shreveport vicinity. This is also expected to support a tornado threat with the more intense supercells. Any supercell that can persist and become dominant may be able to produce a significant tornado or two. A wind-damage threat will also likely develop along the line of storms, with the greatest potential located across Ark-La-Tex, where an Enhanced risk has been introduced. ....East Texas/Louisiana... Further south into east Texas and Louisiana, storm coverage is expected to be more isolated from the late evening into the overnight period. In this area, to the south of the mid-level jet axis, instability is not expected to be as strong. Also, lift may not be quite as concentrated. For this reason, supercell development is expected to remain more isolated. Any cell that can become organized and sustained could produce isolated large hail, wind damage and a tornado or two. The severe threat should more isolated with southward extent, with only a marginal severe threat expected near in the coastal sections of southeast Texas and southern Louisiana. ...Broyles/Lyons.. 01/11/2024 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .