The eastward movement of a large-scale weather system will continue on Sunday this, along with the continuous rise of dew points in the pre-frontal warm sector could boost afternoon destabilization, these conditions could cause a wide region of severe risk to develop. This area will include the Mid and Lower Mississippi/Lower Ohio/Tennessee Valleys.  All severe weather hazard could be possible. 

The Storm Prediction Center has the entire state of Kentucky already in a level 2 slight risk area for possible storms. We are still almost a week away so keep checking back for updates as we get closer to the weekend. 

 

 

 

On Sunday, the area of greatest severe risk is predicted to move from Missouri, Arkansas, and northern Louisiana, move eastward over the day, and finally get close to the Appalachian west slopes.

A moist warm sector will destabilize over the day as the western U.S. upper trough moves into the Plains, facilitating the deepening of surface low pressure. This is likely to result in storm development, first west of the Mississippi Valley and then moving eastward through the evening. When combined with other factors, the favorable thermodynamic environment will indicate the possibility of severe storms, including supercells, with all-hazards potential.

 

 

Favorable ingredients for strong to severe thunderstorms are possible ahead of an approaching low-pressure system on Sunday. All severe threats are possible, including the potential for some rotating storms. Stay up to date on the latest forecasts, but now is the time to prepare. Does your family have a safety plan?

Confidence is increasing for severe thunderstorms Sunday and Sunday night.

All severe hazards are possible, including:

Damaging Winds

Large Hail

Tornadoes

Timing is uncertain, but that will come into more focus as we get closer.

Widespread rainfall amounts of 1-2". A path of 2-3" may develop over northern Kentucky. Heavy rainfall rates in thunderstorms will increase flash flooding potential.

Before a cold front moves eastward into the Mississippi and Ohio Valleys and subsequently the Tennessee Valleys, a very big region of severe potential is still visible for Sunday.
In conjunction with daytime heating, the northward movement of 60s dewpoints anticipated ahead of this front will increase mixed-layer CAPE (convective available potential energy) into the 1000–1500 J/kg range and possibly above 2000 J/kg further southwestward along the front from East Texas into the lower Mississippi Valley. CAPE needs to be at least 1000 J/kg for strong to severe thunderstorms to form. 

In the afternoon, strong to severe storms are predicted to form close to and ahead of the boundary, possibly reaching as far southwest as East Texas. Large hail and damaging winds are possible, but the chance of supercell storms also raises the possibility of a few tornadoes. Throughout the evening, the risk will move southeast into the Tennessee Valley and central Gulf Coast states, as well as eastward throughout parts of the Midwest/Ohio Valley and Mid/Lower Mississippi Valley. This trend is probably going to continue until the conclusion of the period.

I will start posting a more detailed forecast by tomorrow. This will be in the range of the convection NAM 3km model.

The Storm Prediction Center has already issued a level 3 enhanced risk area for severe thunderstorms this Sunday. So in accordance with what the SPC has issued, I'm going to go ahead and go into a BGP Severe Weather Alert Day for Sunday. Mainly because it's a late evening to nighttime event for Kentucky.

The Ohio/Mid and Lower Mississippi/Lower Missouri/Tennessee River Valleys are at the center of a region that is expected to experience widespread/substantial severe weather. Strong tornadoes, destructive winds, and extremely huge hail are anticipated.

Conditions will favor the formation of supercells, which are expected within this environment, and very large hail is expected given the conditions in the upper atmosphere.  Along with the hail risk, damaging wind gusts are expected -- particularly where storms form into a line.  Additionally, this setup appears very favorable for tornadoes, a few of which may be strong/potentially long-live'd. 

Everyone should be going over their emergency action plan as soon as possible and be prepared for power outages. Also have more than one way to receive weather alerts for your area.

 

This is the probability outlook map showing a 30% chance for severe storms for most of Kentucky. Which is considered high for severe storms. 

 

 

 

 

This update will show why the SPC has most of Kentucky under a level 3 enhanced risk area for Sunday night. 

This is a skewed T chart. It is used to predict the severity of severe storms. First look at the upper right-hand box. The red and green lines. The red represents air temperatures, and the green represents dew points. You can see the difference of 7° between the air and dew points, 73°F (red) and 66°F (green). Any difference less than 20 is favorable for tornadoes. Next, the LCL (green) basically shows how low the cloud base will be relative to the ground. LFC (yellow) could also be called the cap, which is the level at which the air becomes warmer than the surrounding air and continues to rise. These need to be close together for tornadoes to possibly form.

Next, look at the middle box at the bottom. The EFF inflow SRH is showing 315, and reading greater than 150 could mean strong tornadoes. The ML Cape in the upper left next to the middle box is showing a reading of 2892 J/kg. This means a moderate to strong instability is present. Strong because it is close to 3000 J/kg.

Last, the STP(cin) is reading 4.8 out of 15. Based on this, a possible PDS strong tornado is possible, reaching EF3 to a low-end EF-4. This is shown in the bottom right-hand box.

The map shows the area for which this reading is taken around 8 pm EDT Sunday. This isn't the time of the storms, just conditions ahead of the possible storms. 

 

I will be posting more later today.