Tornadotony.com
Day 1 Convective Outlook
Valid from 6 AM CST Monday, March 3rd, 2008, to 6 AM CST Tuesday, March 4th, 2008
Issued at 11:00 PM CST Sunday, March 2nd, 2008
…There is a High Risk of severe weather in Much of Louisiana, West-Central Mississippi, and Souteastern Arkansas…for the threat of an outbreak of large, violent, long-tracked tornadoes…
…There is a Moderate Risk of severe weather surrounding the High Risk, including Extreme Eastern Texas, Western and Southern Louisiana, Southern Missississippi, Western Alabama, and the Western Florida Panhandle…
…There is a Slight Risk of severe weather surrounding the Moderate and High Risks, and extending northward to the Lower Ohio River Valley…
***A MAJOR SEVERE WEATHER OUTBREAK IS LIKELY OVER THE LOWER MISSISSIPPI VALLEY TOMORROW, WITH STRONG TO VIOLENT TORNADOES, LARGE HAIL, AND DAMAGING STRAIGHT-LINE WINDS LIKELY***
***LOCATIONS IN THE HIGH RISK INCLUDE: ALEXANDRIA LA, MONROE LA, NATCHEZ MS, BATON ROUGE LA, VICKSBURG MS, JACKSON MS, MCCOMB MS***
Synopsis
Strong positively tilted trough currently amplifying across the Great Plains. Sfc cyclogenesis will occur along the Gulf Coast in advance of the trough. Strong cold front will slow down slightly as cyclone lifts northeastward, dividing cold air to the west and north and warm, moist air advected in to the south and east. Warm moist air will be advected in by a 60 kt LLJ overnight and over the day tomorrow. Strong shear at all levels, along with deep boundary layer moisture and moderate instability, will create an environment condusive for strong, long lived tornadic supercells tomorrow across the MDT and HIGH risk areas.
Lower Mississippi into the Southeast
Thunderstorms, some possibly severe, should be ongoing at the beginning of the period in Eastern Texas. Further east, significant low level moisture advection and cold mid level temps will help with destabilization, contributing to SBCAPEs invof 500-1500 J/kg in the MDT/HIGH risk areas. Any insolation will further increase destabilization, with values possibly reaching 2000J/kg in the warm sector. The storms should move eastward and break up into more discrete storms in Louisiana as dynamic forcing shifts northward into AR. The strong LLJ will contribute to curved, long hodographs, supportive of strong to violent tornadoes with the supercells that move into the area. Further south and east, additional supercells could develop in the weakly capped free warm sector, and the hodographs support significant long track tornadoes with these as well. 0-1km SRH of 250-500m**2s**-2 and deep-layer shear of 70kt will likely be achieved across the High Risk region, which, with weak linear forcing, should lend to conditions favorable for long-tracked supercells capable of producing violent families of tornadoes over long distances.
Activity should slowly recongeal into a squall line further east in central Mississippi as base of longwave trough induces strong height falls over the cold front. Though instability may wane a bit with loss of daytime heating, continued strong low level shear will continue the threat of strong tornadoes overnight. In addition, minimal inhibition across Alabama will lead to the possibility of additional pre-frontal convection. Any storms that form ahead of the squall line will likely produce strong-violent tornadoes. However, uncertainty in exact eastward progression of front and of coverage of overnight prefrontal activity precludes and eastward extention of the high risk at this time.
Further north, linear forcing will promote a squall line that will push eastward across Tennessee. Given strong kinematic fields, damaging winds are possible with this line, even with minimal instability. An isolated tornado or hail event also cannot be ruled out.
This is a very dangerous situation. Please keep apprised of the latest severe weather developments in your area.
THIS IS NOT AN OFFICIAL FORECAST. Please consult the Storm Prediction Center or your local National Weather Service office for official critical and life-saving information.
Jim and Tony