MD 1208 CONCERNING SEVERE THUNDERSTORM WATCH 387… FOR TX BIG COUNTRY
Mesoscale Discussion 1208 NWS Storm Prediction Center Norman OK 0525 AM CDT Sat Jul 01 2017 Areas affected...TX Big Country Concerning...Severe Thunderstorm Watch 387... Valid 011025Z - 011230Z The severe weather threat for Severe Thunderstorm Watch 387 continues. SUMMARY...Locally strong/damaging wind gusts cannot be ruled out through early this morning across the Texas Big Country as a solid band of storms advances to the east-southeast. The need for a new severe-thunderstorm watch is unlikely, at this time, for areas downstream across the southwest portion of the FWD county warning area and the adjacent part of the EWX county warning area. DISCUSSION...At 0950Z, mosaic radar imagery showed a solid band of storms extending from Haskell County to northwest Coke and southeast Mitchell counties, with the southern extent of this band having the fastest movement to the southeast at 40 kt. This faster storm motion is likely due to better proximity to stronger 2-hourly surface pressure rises of 4-mb within the attendant cold pool. In addition, early morning surface and radar imagery analysis detected a composite convective outflow boundary extending from northeast TX (25 SE GGG) westward to 40 E SEP to near MKN and BWD, then west-northwestward to northeast Coke County and southwest to 35 S MAF. The main band of storms has remained north of the outflow boundary, and should continue to move the southeast through the eastern part of WW 387, given northwesterly shear vectors remaining perpendicular to the convective band. Recent surface observations with the passage of the band of storms have remained sub-severe. Although a strong/damaging wind gust cannot be ruled out, given the strong surface pressure rises, warming cloud tops with this MCS and weakening/veering low-level jet suggest the overall severe-weather threat is likely waning. Meanwhile, higher theta-e air near and south of the composite convective outflow boundary across the southwest portion of FWD county warning area into adjacent counties of EWX county warning area suggest more favorable inflow air to sustain any remaining thunderstorms that reach those areas. However, the weakening low-level jet should limit ascent into the southern part of the MCS and preclude a greater severe-weather threat this morning that would warrant a new WW. This scenario is supported by the last several HRRR runs, showing the stronger storms weakening by 15Z from SJT to BWD to near FTW. ..Peters.. 07/01/2017 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FWD...SJT...MAF... LAT...LON 32030099 32320016 32949980 33129970 33159944 32869880 32509876 31949829 31379839 31229890 31249961 31440024 31770085 32030099
from SPC Mesoscale Discussions http://bit.ly/2uuyMFh
Be First to Comment