Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
143 ACUS02 KWNS 311734 SWODY2 SPC AC 311733 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Fri May 31 2024 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Scattered severe storms, including a few supercells, may develop across the central and southern High Plains Saturday afternoon, before evolving into organizing clusters while spreading into the adjacent Great Plains through Saturday evening. These may pose a risk for severe wind, hail and perhaps a couple of brief tornadoes. ...Synopsis... Upper-level ridging will extend from the Tennessee Valley to the Northeast Saturday with a series of weak mid-level shortwave troughs extending west from there across the central and western CONUS. The strongest of these will be near the Mid-Mississippi Valley with an associated weak surface low moving northward near the Mississippi River during the day and through the Lower Ohio River Valley during the evening and overnight period. Farther west, some weak lee troughing will occur from the central to the northern High Plains as a shortwave crosses the Mountains, particularly Saturday night. ...Central High Plains... A relatively diffuse dryline will be present across eastern Colorado and Southwest Wyoming during the day with some sharpening and increasing convergence during the afternoon as lee troughing strengthens. Strong heating should erode inhibition by early afternoon along and ahead of the dryline. Therefore, expect high-based thunderstorm development across most of the dryline from eastern Wyoming/NE Panhandle to southeast Colorado amid 35 to 40 knots of effective shear. Supercell storm mode will be favored initially, but should transition into one or more clusters by late afternoon/early evening given the deeply mixed thermodynamic profile favorable for strong downbursts. There is an increased signal for a forward propagating MCS to persist into northwest Oklahoma during the late evening, particularly from the HRRR and WRF-ARW. In fact, the HRRR indicates a continued threat through the overnight period into central Oklahoma. However, this is contingent on upper 60s to low 70s dewpoints advecting northward and resulting in increasing instability Saturday night across western and central Oklahoma. While possible, the presence of this better quality moisture is quite uncertain given Day 1 outflow boundaries continue to move south across Texas near mid-day Friday and additional convection Friday afternoon/evening which will impact moisture quality. ...Southern High Plains... Strong heating will result in an uncapped airmass along the dryline from eastern New Mexico to Far West Texas by early afternoon. A relative weakness in the mid-level flow across eastern New Mexico may limit storm organization somewhat in this region. However, the deeply-mixed airmass and moderate instability will support a large hail and severe wind threat. A more organized storm threat is likely from the Trans Pecos to the Big Bend where a stronger (35-40 knot) subtropical jet streak overspreads the region. A few supercells are expected in this area with the potential for severe wind gusts, 2+ inch hail, and perhaps a tornado. ...Southeast Texas into the Southeast... A moist airmass will be present from Southeast Texas to southern Mississippi on Saturday with strong instability developing by mid afternoon. Thunderstorms will likely develop along the sea breeze by mid afternoon. Shear will be relatively weak (~25 knots), but may be sufficient for some multicell clusters capable of damaging wind gusts. Better shear will be present closer to the remnant mid-level shortwave trough MCV moving through the Mid-Mississippi Valley, but surface heating will be limited in this region which will likely prevent more robust updraft development capable of utilizing this more favorable shear. ..Bentley.. 05/31/2024 $$