Mesoscale Discussion 1583 NWS Storm Prediction Center Norman OK 0404 AM CDT Sun Aug 27 2017 Areas affected...Upper Coastal Plain of Texas Concerning...Tornado Watch 470... Valid 270904Z - 271000Z The severe weather threat for Tornado Watch 470 continues. SUMMARY...The tornado risk is very low with outflow-dominant storm structures given the marginal environment. Once supercell structures redevelop, the tornado risk will correspondingly increase. DISCUSSION...Radar imagery from KHGX has shown 2 north-south bands over the Upper Coastal Plain of Texas with outflow-dominant structures primarily within the bands. This is likely due in part to the magnitude of water loading within the downdrafts and the inability for a quasi-discrete mode to emerge from the convective bands. Although a brief/weak tornado cannot be ruled out from within these bands, it seems the risk is very low. On the other hand, the background wind profile per KHGX VAD data has shown a decrease in hodograph size over the past several hours with 0-1 km SRH decreasing to less than 100 m2/s2. With the maritime front located in west-east orientation from near HOU east to immediately north of the mouth of the Sabine River, the largest hodographs will likely be confined to this corridor with backed easterly surface flow. However, little in the way of supercell structure has developed over the near-coastal waters from Galveston Bay east to the Sabine River. Until this occurs, the tornado risk will likely remain low until the combined environment and convective morphology become more favorable. ..Smith.. 08/27/2017 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LCH...HGX... LAT...LON 28629593 30309592 30499470 29759364 28629593Read more
from SPC Forecast Products http://ift.tt/1bP63Qt
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