Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Sun Apr 02 2017 Valid 021300Z - 031200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM EAST TEXAS TO EXTREME SOUTHERN ARKANSAS...CENTRAL/NORTHERN LOUISIANA...AND EXTREME WEST CENTRAL MISSISSIPPI... ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS TO CENTRAL MISSISSIPPI... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE ENHANCED RISK AREA... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT RISK AREA...FROM THE LOWER TEXAS COAST TO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... A severe thunderstorm cluster will likely affect central/northeast Texas into southern Arkansas and northern Louisiana today with widespread damaging winds, a few tornadoes, and large hail. Tornadic supercells will be possible from east central Texas across central and northern Louisiana, immediately south of larger thunderstorm cluster track. The risk for damaging winds and a few tornadoes will persist overnight across Louisiana and Mississippi. ...A complex, but potentially significant severe-weather episode with tornadoes, damaging winds, and large hail is expected today through tonight from east Texas into Mississippi... ...MCS path from central Texas to southern Arkansas/northern Louisiana today... A closed midlevel low now over northern Mexico will begin the process of ejecting northeastward toward the Ark-La-Tex in response to upstream height falls over the Pacific coast and Great Basin. Preceding the midlevel trough, a large thunderstorm cluster has persisted overnight near Del Rio, with cold pool formation becoming more apparent with time with this cluster. Persistent diabatic heating with the cluster will also lead to mesolow/MCV formation as the convection moves northeastward today along a slow-moving surface front, in advance of the ejecting midlevel trough. Rich low-level moisture (boundary layer dewpoints in the low-mid 70s) beneath a remnant elevated mixed layer plume is contributing to strong buoyancy (MLCAPE of 2000-3500 J/kg) in the warm sector this morning across south TX. The warm sector will spread northeastward in tandem with the MCS, which should eventually develop bowing characteristics. East-southeast of the MCS, low-level warm advection on the northeast side of the warm sector will support an increase in thunderstorm development across east TX through the morning. The morning warm-advection storms may remain slightly elevated, though gradual surface warming through midday and strong low-level and deep-layer vertical shear will favor supercells. The net result of this complex evolution should be an intensifying/bowing MCS with merging cells and an increasingly widespread damaging wind risk, as well as the potential for tornadoes with embedded circulations through the afternoon/evening. ...Immediately southeast of the MCS track this afternoon/evening from east Texas to central/northern Louisiana... Boundary layer destabilization through the day will make surface-based supercell development more likely from east TX into central/northern LA, immediately south of the MCS path. Semi-discrete storms are expected to mature in the warm sector and potentially interact with the outflow boundary trailing from the MCS a little farther north. Any sustained supercells, especially along the I-20 corridor in LA this afternoon/evening, will be capable of producing strong tornadoes and very large hail. ...Louisiana/Mississippi overnight... Additional severe storm development is expected by this evening into tonight from extreme southeast TX into LA, ahead of the surface cold front. This convection will form in an environment favorable for supercells, though storm interactions should lead to upscale growth into another band/line. The more discrete storms, as well as circulations embedded within the line, will pose a risk for damaging winds and a few tornadoes overnight into MS, while the convective band could approach west-central or northwest AL near sunrise. ..Thompson/Cohen.. 04/02/2017Read more
from SPC Forecast Products http://ift.tt/rATNzD
No comments:
Post a Comment