Subj : DAY1SVR: Day 1 Convective To : All From : Mike Powell Date : Fri Feb 02 2024 09:39:00 ACUS01 KWNS 021255 SWODY1 SPC AC 021253 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0653 AM CST Fri Feb 02 2024 Valid 021300Z - 031200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF NORTHWEST TEXAS TO PARTS OF SOUTH-CENTRAL TEXAS AND THE NEARBY RIO GRANDE VALLEY... ....SUMMARY... Severe hail, damaging gusts and a tornado or two are possible over parts of the southern Plains, from late afternoon into this evening. ....Synopsis... A highly amplified, somewhat progressive mid/upper-level pattern is forecast through the period, with ridging shifting slowly eastward across central Canada and the Mississippi Valley. Upstream, height falls will spread across the Rockies and Great Plains States. The most convectively impactful feature will be a basal shortwave trough -- with several associated vorticity maxima -- initially evident in moisture-channel imagery over portions of southern CA, the lower Colorado River Valley, and northwestern MX. The trough should shift eastward and strengthen, extending from the Four Corners area across central/southern NM past ELP and over Chihuahua around 00Z. By 12Z, a closed 500-mb low should develop over northeastern NM, with the trough south-southeastward across the Llano Estacado and Permian Basin to Coahuila. At 11Z, surface analysis showed lee troughing over eastern parts of CO and NM, with a few weak/attached lows, as well as pockets of 60s F surface dewpoints reaching as far north as the SAT-AUS region. A diffuse Pacific cold front was apparent over east-central NM and far west TX, and should sharpen through the day as it crosses west TX. A dryline was drawn from northwest TX southwestward over the Permian Basin, then south-southeastward into higher terrain of northern Coahuila. This dryline should mix eastward through this afternoon to the Edwards Plateau on the south side, and move little on the north side. The lee trough should strengthen throughout the period, with cyclogenesis expected overnight in the area from the northwestern TX Panhandle to southeastern CO. The Pacific front to its south and southeast should overtake the dryline and shift eastward from west TX into central and south TX tonight. ....TX/OK... Episodes of strong-severe thunderstorms are expected to cross the outlook area starting this afternoon along/ahead of the dryline -- initially moving roughly northward over in the northwest TX/eastern Panhandle/western OK region. Isolated severe hail, damaging gusts and potential for a brief tornado exists with this activity. A later but more-substantial severe threat is apparent across parts of northwest, central and southwest TX, east of late-afternoon/early-evening development areas along: 1. The dryline, 2. The Pacific front, and 3. Eastern slopes of the Serranias del Burro of Coahuila leading down to the Rio Grande. Supercellular and bowing/quasi-linear modes are possible in and near the "slight" area, offering sporadic severe hail, isolated severe gusts and potential for a tornado or two. Some hail may exceed 2 inches in diameter from supercell(s) in the first few hours of the convective cycle over parts of south TX (southern Hill Country southward). In that area, the most-favorable combination of steep deep-layer lapse rates, inflow-layer moisture, and long hodographs is expected. Large-scale lift will strengthen through tonight across much of the southern Plains -- under the influences of low-level warm advection and midlevel DCVA. Also, as a 125-160-kt 250-mb jet extends inland across southern CA and northwestern MX -- behind the mid/upper trough -- its left-exit region and associated lift aloft should spread this evening and overnight across parts of central/south TX, where the steepest midlevel lapse rates (exceeding 7 deg C/km) are expected. These influences will extend atop a moistening and diurnally destabilizing boundary layer with surface dewpoints in the 50s F over northwest TX and OK, and 60s in the Edwards Plateau and Hill Country southward to the Rio Grande. Adequate deep-layer instability/buoyancy for surface-based convection is expected on either side of the dryline today, and along/ahead of the Pacific front tonight. Peak/preconvective MLCAPE should reach around 1000-1500 J/kg in a narrow, south-north corridor ahead of the dryline, diminishing eastward toward east TX. Low-level shear may be stronger over northern parts of the outlook, but with greater deep shear southward toward the more-intense mid/upper winds. ...Edwards/Leitman.. 02/02/2024 $$ --- SBBSecho 3.14-Linux * Origin: Ilink: CCO - capitolcityonline.net (454:1/105) .