MD 0533 CONCERNING SEVERE THUNDERSTORM WATCH 152… FOR PORTIONS OF THE OK/TX PANHANDLES INTO WESTERN AND CENTRAL OK
Mesoscale Discussion 0533 NWS Storm Prediction Center Norman OK 0344 AM CDT Fri Apr 21 2017 Areas affected...Portions of the OK/TX Panhandles into western and central OK Concerning...Severe Thunderstorm Watch 152... Valid 210844Z - 211045Z The severe weather threat for Severe Thunderstorm Watch 152 continues. SUMMARY...Recent storm development is being monitored in northeast NM into the northwest TX Panhandle, which is likely the start of the next round of strong to severe storms forecast to spread to the east/southeast across the OK/TX Panhandles into western and central OK through the morning. This will likely warrant a new WW issuance prior to the expiration of WW 152. Meanwhile, isolated strong to severe storms will continue across west-central OK, with storms weakening east of the I-35 corridor. DISCUSSION...At 08Z, the strongest storms with some severe hail threat were persisting within and just east and southeast of WW 152. These more isolated storms should eventually weaken, as they move east of the I-35 corridor, where instability is much less than currently analyzed across the western half of OK and western north TX into the TX Panhandle. Meanwhile, trends in IR satellite imagery have indicated an increase in convective clouds/cooling cloud tops across northeast NM into the northwest TX and OK Panhandles, where there has also been a recent uptick in reflectivity per mosaic radar imagery and CAPPI data. This activity indicated the increase in large-scale ascent spreading into the southern Plains this morning with the approach of a central/southern Rockies shortwave trough and accompanying southeastward-digging mid-upper level jets. Attendant height falls have resulted in veering and strengthening 850-mb winds across much of west TX (from AMA southward) allowing for low-level moistening. These factors combined with very steep midlevel lapse rates across much of the TX/OK Panhandles into western OK has resulted in ongoing strong destabilization during the overnight hours with MUCAPE ranging from 1500-2000 J/kg as of 08Z. The recent uptick in reflectivity across northeast NM and part of the northern TX Panhandle has been depicted by the last several runs of the HRRR, with each run suggesting a further increase in storm development toward the east and somewhat to the southeast through this morning. HRRR further suggests an eventual upscale growth into a linear MCS as storms spread into western OK between 13-15Z, reaching the I-35 corridor by late morning. Large hail will be the initial severe-weather risk followed by a combination of damaging winds and hail as the storms become more linear. ..Peters/Edwards.. 04/21/2017 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OUN...LUB...AMA... LAT...LON 35860234 36380114 36429984 36279740 36119679 35439663 34229666 34139713 34009789 34269891 34509980 34610112 34590148 35140199 35860234
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