Extreme Tornado Outbreak likely today in the mid south

Heed all warnings from your local weather service office today and monitor the weather situation continuously this afternoon and evening as conditions change rapidly if you live in the hatched area above. Atmospheric conditions are already set in motion to bring on intense rapidly moving severe weather systems ranging from extreme straight line winds, to large hail, to long track F2 to F5 tornadoes. There will be very little warning time today because the winds aloft steering the severe weather will be near or above hurricane strength. Tornadoes are forecast by NWS experts to track at 50mph to 65mph. There is already extreme wind shear caused by a raging jet steam caused by the merging of the subtropical jet stream with the polar jet stream, bringing on wind speeds of up to 150 mph out of the southwest at high levels blowing over a warm humid air surging in from the Gulf of Mexico at hurricane force speeds of about 75 miles per hour.

If you live in the hatched area above you need to have a plan to find safety fast if you get a warning. The severe weather situation could come on so quickly that you could get trapped in traffic if you are driving somewhere. Professional storm chasers could get trapped as well.

The Storm Prediction Center of NOAA’s National Weather Service rarely issues it’s highest level warning. They issued one a week ago ahead of the tornado outbreak in Alabama. Fortunately, last week’s outbreak had conditions that favored weaker tornadoes. Today’s conditions are far worse.

This is the situation I feared months ago when a major warming in the stratosphere injected momentum into the jet stream. Because this is a La Niña year which favors a storm track with cold air aloft dropping over the southern Rock Mountains and warm Gulf air pushing into the Mississippi valley I was concerned that a day like this would happen this spring. Today we see that pattern on steroids. The increasing heat content of north Atlantic ocean and Gulf of Mexico waters is providing the fuel — water vapor — for more severe thunderstorms and severe weather. Tornado activity is highly irregular so it is hard to find trends in tornado patterns, but severe weather such as we expect today is getting more severe because of climate change associated with ocean heating.

I am not an expert on tornadoes but here’s what the expert at NOAA’s SPC said.

“An uncommon upper echelon parameter space”

In other words all hell is ready to break loose.

I have looked at numerous weather maps, forecasts and soundings over the past 5 days and the developing severe weather situation is one of the worst I have ever seen. However, I am not an expert on severe thunderstorms, so I have let professionals have their say. I’m still learning.

The jargon may confuse the general public but the words below are chilling to me. www.spc.noaa.gov/...

Southeast to Ohio Valley...   Scattered to numerous thunderstorms are expected from midday through   afternoon over parts of the lower Mississippi Valley region and   Mid-South.  This activity will race northeastward while maturing   into cyclic supercells and bow echoes.  Tornadoes are the main   concern (some strong to violent).  Also, severe nontornadic winds   may exceed 65 kt locally, and sporadic large, damaging hail also is  possible.  

A relatively undisturbed low-level warm sector with rich moisture   should shift further inland along and south of the marine warm   front, with a very favorable buoyancy/shear pattern over a broad   area.  Surface dew points in the upper 60s to low 70s F already are   common over central/southern LA, southern MS and southwestern AL.    This moisture will spread northward over at least the "high" and   "moderate" areas today, where the southern and eastern parts of   strongest deep-layer winds will overlap the greatest low-level   instability.  There, diurnal heating will remove MLCINH from midday   onward, contributing to ready thunderstorm development, both in the   destabilizing warm sector and near the cold front.  Meanwhile,   expect strengthening deep shear and large, almost ideally shaped   low-level hodographs formed in part by a wide, 60-70-kt LLJ.    Accordingly modified RAOBs and forecast soundings yield peak MLCAPE   of 2000-2500 J/kg, amidst 65-75-kt effective-shear vectors, and   effective SRH values of 400-700 J/kg.  

This is an uncommon, upper-echelon parameter space.  In such an  environment, any relatively discrete supercells will be capable of   multiple tornadoes, some long-tracked and strong to violent (EF2-5   possible), with considerable destructive potential.  A very moist   boundary layer also will reduce potential cold-pool/outflow strength   via less subcloud evaporation, so that even closely spaced storms   may have substantial tornado threats.  Forecast wind fields and   model soundings reasonably suggest any sustained supercells and   their tornadoes will be fast-moving (45-55 kt), with individual   tornado paths nearly as long in miles as their duration in minutes.

To put it into simple terms, the wind shear and low level upwards spin (helicity) that trigger severe thunderstorms and extreme violent tornadoes are at maximum levels.  In particular, the helicity levels are extraordinary for a warm unstable air mass. Please check in with your loved ones if you are in the checked region on the top map. Long track tornadoes could track well out of the hot pink zone because strong supercells can act as their own weather systems. Please listen to your local weather office or respected media meteorologists today and heed all warnings. This is real.