Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
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651 ACUS01 KWNS 180053 SWODY1 SPC AC 180051 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 PM CDT Tue Sep 17 2024 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE HIGH PLAINS... ...SUMMARY... Thunderstorms capable of producing scattered to numerous severe wind gusts and hail will continue to develop across the High Plains this evening. Some of the wind gusts may be significant (75+ mph). ...Southern and Central High Plains... A mid-level low is evident on water vapor imagery over the northern Rockies, with cyclonic southwesterly flow located from the Four Corners into the central and northern Plains. Ahead of the trough, a band of strong large-scale ascent appears to be spreading into the central High Plains, where a large plume of mid-level moisture is located. Thunderstorms are ongoing ahead of this band of ascent, and are moving into a moderately unstable airmass where MLCAPE is estimated to be in the 1000 to 2000 J/kg range. Concerning the shear environment, regional WSR-88D VWPs in east-central Colorado have 0-6 km shear from 40 to 50 knots, with some directional shear in the lowest 3 km. In addition, the RAP has a strengthening low-level jet analyzed from far eastern Colorado and western Kansas northward into southeastern South Dakota. As the low-level jet continues to strengthen, the lift, shear and instability will continue to support severe thunderstorm development over the southern and central High Plains this evening. In response, an organized line segment will continue to move eastward across western Nebraska, western Kansas and the Texas Panhandle, where scattered severe wind gusts are expected. Wind gusts above 70 knots will be possible along the more organized parts of the line. The threat should persist into the mid to late evening. ...Northern High Plains... Water vapor imagery shows an upper-level low over eastern Idaho, with divergent mid-level from the south and south-southeast across much of the northern High Plains. An axis moderate instability is analyzed from central North Dakota into northeastern Montana, where MLCAPE is estimated in the 2000 to 3000 J/kg range. Thunderstorms are ongoing near the instability axis in northeastern Montana. Additional storms have developed further south near the South Dakota-Wyoming state line. The latest WSR-88D VWP at Glasgow, Montana has easterly flow at the surface, with a sharply veering wind profile in the low-levels. 0-6 km shear is estimated to be near 40 knots. This environment, along with steep low to mid-level lapse rates should continue to support a severe threat for several more hours. A potential for severe wind gusts and isolated large hail will exist with the stronger storms. ..Broyles.. 09/18/2024 $$