MD 0085 CONCERNING TORNADO WATCH 10… FOR SOUTHEAST LOUISIANA AND SOUTHERN MISSISSIPPI
Mesoscale Discussion 0085 NWS Storm Prediction Center Norman OK 0255 AM CST Sat Jan 21 2017 Areas affected...Southeast Louisiana and southern Mississippi Concerning...Tornado Watch 10... Valid 210855Z - 211100Z The severe weather threat for Tornado Watch 10 continues. SUMMARY...Severe weather including a tornado threat will persist across southeast Louisiana and southern Mississippi during the overnight. The greatest threat for tornadoes in the short term is expected to be from the vicinity of BTR and eastward from Hammond, LA to Hattiesburg, MS with the increase in supercell development. DISCUSSION...Recent surface analyses /06-08Z/ indicated a developing mesolow, now located near BTR, with the strongest pressure falls from BTR to MCB, while this region and into southwest and south-central MS also has the coldest cloud tops and greatest lightning coverage/density. The mesolow is expected to track to the east-northeast along a northward-developing warm front through southern MS to central AL (near or just south of a TCL-BHM line) per trends in mesoanalyses and HRRR forecasts. Forcing for ascent associated with a progressive and compact shortwave trough moving into Louisiana at this time will sustain a low-level mass response across and downstream from WW 10. This response is being observed per backed southerly low-level winds with an associated increase in low-level moistening and warm air advection. These factors will further aid in the development of additional thunderstorms east of the main BTR-MCB storm complex into southeast MS and southwest AL through the overnight. Further strengthening of vertically veering wind profiles and increasing deep-layer ascent per an apparent coupled jet structure with the progressive trough suggest supercells should increase in coverage and intensity across WW 10. ..Peters.. 01/21/2017 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BMX...MOB...JAN...LIX...LCH... LAT...LON 29449124 30539175 31379168 31879103 32518987 32928915 32928835 31048845 29848835 29078862 28828910 28718955 28858997 28779109 29179122 29449124
from SPC Mesoscale Discussions http://bit.ly/2jzNzdN
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