SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1249 AM CDT Sat Jul 10 2021 Valid 101200Z - 111200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN AND CENTRAL PLAINS INTO THE OZARKS... ...SUMMARY... Severe thunderstorms with wind damage and isolated large hail are expected to develop today from parts of the southern and central Plains east-northeastward into the Ozarks. Additional severe storms with isolated wind damage and hail may also develop in parts of the mid Mississippi Valley. Marginally severe storms will be possible in the parts of the Desert Southwest and southern Rockies. ...Southern and Central Plains/Ozarks/Mid Mississippi Valley... An upper-level trough will dig southeastward into the central Plains today as an associated 40 to 50 kt mid-level jet moves southward across the central and southern Plains. At the surface, a cold front will advance southeastward across Kansas, northwest Oklahoma and the Texas Panhandle. Surface dewpoints along and ahead of the front will be in the lower to mid 70s F, resulting in moderate to strong instability by afternoon. An outflow from morning convection is forecast to be located across eastern Kansas and central Missouri. This outflow boundary is expected to be the favored initiation zone for surface-based thunderstorms during the early to mid afternoon. A complex of thunderstorms will likely organize across southeast Kansas and southwest Missouri during the mid to late afternoon. A linear MCS is forecast to develop from this convection, moving southward across much of Oklahoma, southern Missouri and northern Arkansas during the late afternoon and evening. A 40 to 50 kt mid-level jet will move southward across the central Plains during the afternoon reaching the southern Plains by early evening. RAP forecast soundings at 00Z/Sunday in southeast Kansas show evidence of the jet, with 0-6 km shear in the 55 to 60 kt range. This combined with directional shear in the low-levels and steep low-level lapse rates will be favorable for damaging wind gusts. The environment should support the development of a linear MCS, with this complex persisting into the early to mid evening. The greatest potential for damaging wind gusts will be from central Oklahoma into southwest Missouri and northwest Arkansas where the combination of instability and shear is forecast to be maximized. An enhanced risk has been introduced for this area. Isolated large hail will also be possible with the stronger cells within this complex. Further to the east into the mid Mississippi Valley, severe thunderstorm development will also be possible this afternoon. However, instability and deep-layer shear is forecast to be considerably less, which should make any potential for wind damage and hail more isolated. ...Desert Southwest/Southern Rockies... An upper-level ridge will remain in place today across the western U.S. As surface temperatures warm during the day, scattered convection will develop in the higher terrain of Arizona and New Mexico. Moderate instability and steep low to mid-level lapse rates will be favorable for marginally severe wind gusts. The greatest potential may exist along the southeastern part of the Mogollon Rim in eastern Arizona and in southwestern New Mexico where model forecast suggest the strongest instability will develop. ..Broyles/Wendt.. 07/10/2021 Read more LIVE: spc.noaa.gov
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