United States Severe Weather

[JLM]

I got bored and started thinking, what if i create a thread specific to severe weather events? I thought about this partly because of the event that has occurred across portions of Texas and Oklahoma today, this activity is spreading over Arkansas as i type this.

If you do not know, the Storm Prediction Center has 5 severe weather risk categories.
Marginal (1/5) - 5% severe threat
Slight (2/5) - 15% severe threat
Enhanced (3/5) - 30% severe threat
Moderate (4/5) - 45% severe threat
High (5/5) - 60% severe threat

So what do the percentages mean? Well, say you are under a Slight Risk, this means there is a 15% chance of seeing severe weather within a 25 mile radius of a point. The higher the risk level, the higher the likelihood is for seeing severe weather.

Im also going to break down the wind, hail, and tornado percentages and what those percentages usually correlate to on the Categorical outlook.

Wind:
5% - typically associated with a Marginal risk
15% - typically associated with a Slight Risk
30% - typically associated with an Enhanced Risk
45% - typically associated with a Enhanced Risk UNLESS there is a SIG risk, then it would be a Moderate Risk
60% - typically associated with a Moderate Risk UNLESS there is a SIG risk, then it would be a High Risk
SIG - this means theres a 10% chance for **significant** winds associated with severe thunderstorms (65 kt/75 mph or greater) within a 25 mile radius of a point

Hail:
5% - typically associated with a Marginal Risk
15% - typically associated with a Slight Risk
30% - typically associated with an Enhanced Risk 
45% - typically associated with a Enhanced Risk UNLESS there is a SIG risk, then its a Moderate Risk
60% - typically associated with a Moderate Risk
SIG - this means theres a 10% chance for **significant** hail (2 inches in diameter or greater) within a 25 mile radius of a point

Tornado: (PS...this is where it gets tricky)
2% - typically associated with Marginal Risk
5% - typically associated with Slight Risk
10% - typically associated with Enhanced Risk
15% - typically associated with Enhanced Risk UNLESS there is a SIG risk, then it would be a Moderate Risk
30% - typically associated with Moderate Risk UNLESS there is a SIG risk, then it would be a High Risk
45% - associated with High Risk
60% - associated with High Risk
SIG - this means theres a 10% chance for **significant** tornadoes (EF2-EF5) within a 25 mile radius of a point

This all may be confusing, but in a real situation it isnt as confusing. Tonight there is a Moderate Risk across portions of Texas, Oklahoma, and Arkansas. The risks associated with this is as follows:
Tornado: 15% SIG (warrants Moderate Risk)
Wind: 45% SIG (warrants Moderate Risk)
Hail: 15%

There is a multitude of combinations of these numbers that would result in different risk level outcomes. For instance, you can have a severe event that features a tornado risk below 2% (so not even Marginal), while still having a 45% SIG wind risk and a 5% hail risk. That alone would cause a Moderate Risk.
You can have a severe event that features a 10% tornado risk, a 30% wind risk, and a 45% SIG hail risk and end up with a Moderate.

In other words, if even one of these severe threats for warrants an Enhanced Risk for example, then one will be issued even if the other 2 threats are below the Enhanced level.

Also, the Storm Prediction Center issues Day 4-8 outlooks, which only contain the Slight and Enhanced Risk categories. If the pattern does not support severe weather in the D4-8 time period, then the maps will show "Potential Too Low, if the pattern looks supportive of severe weather, but confidence is too low, then the "Predictability Too Low" tag will be shown on the outlook.. These outlooks are updated once every 24 hours. The Day 3 Outlook has all the 5 categories, but it too is only updated once every 24 hours. The Day 2 Outlook is updated once every 12 hours (twice a day). The Day 1 Outlook is updated multiple times per day.

If you have any questions, please ask! I think this would be an interesting thread that, to be honest, can last all year long. We will see how it goes, and maybe this will increase many Palmtalk user's awareness of severe weather events. I will post a current outlook in just a moment.

[JLM]

Here is the Categorical Outlook. A Moderate Risk (4/5) is in place across portions of Texas, Oklahoma, Arkansas, and a small portion of Louisiana. An Enhanced Risk (3/5) is in place across portions of Texas, Oklahoma, Arkansas, and Louisiana. A Slight Risk (2/5) is in place across portions of Texas, Oklahoma, Arkansas, Louisiana, Missouri, and Mississippi. A Marginal Risk (1/5) is in place across portions of Texas, Oklahoma, Kansas, Missouri, Arkansas, Tennessee, Mississippi, and Louisiana.


Here is the Tornado Threat. There is a 15% risk across portions of Texas, Oklahoma, Arkansas, and Louisiana. A 10% tornado risk is in place for portions of Texas, Oklahoma, Arkansas, and Louisiana. A 5% risk is in place across portions of Texas, Oklahoma, Arkansas, and Louisiana. A 2% tornado risk is in place across portions of Texas, Oklahoma, Missouri, Arkansas, Tennessee, Mississippi, and Louisiana. There is also a SIG risk zone across portions of the 15% and 10% risk zones across Texas, Oklahoma, Arkansas, and Louisiana.


Here is the Wind Threat. A 45% risk is in place across portions of Texas, Oklahoma, Arkansas, and Louisiana. A 30% zone is in place across portions of Texas, Oklahoma, Arkansas, and Louisiana. A 15% risk is in place across portions of Texas, Oklahoma, Arkansas, Missouri, Mississippi, and Louisiana. A 5% risk is in place across portions of Texas, Oklahoma, Arkansas, Kansas, Missouri, Tennessee, Mississippi, and Louisiana. A SIG risk is also in place across the entire 45% risk zone.


Here is the Hail Threat. There is a 15% risk across portions of Texas, Oklahoma, Arkansas, and Louisiana. There is a 5% risk in place across portions of Texas, Oklahoma, Arkansas, and Louisiana.


Here are the current watches in effect. Theres a Tornado Watch (bright yellow) across portions of Texas, Arkansas, and Louisiana. A Severe Thunderstorm Watch (pinkish color) was just recent issued across portions of Arkansas, Mississippi, and Tennessee. The orange boxes across the Tornado Watch area is Severe Thunderstorm Warnings. As of right now, no Tornado Warnings are in effect, but they would be red on this map. There are some Flash Flood Warnings (deep red) in Arkansas and Missouri though.


To explain the other alerts on this map, the brown is a Wind Advisory, the light purple area in Kansas is a Winter Weather Advisory, the bright blue in Texas is a Frost Advisory, the deep bluish/purple is a Freeze Warning, and the darker purple area in Texas is a Hard Freeze Warning. The brighter green boxes in Texas are Flood Advisories, the tan colored boxes are Special Weather Statements (issued for strong storms that are under severe limits). The orange box in the Gulf near Houston is a Special Marine Warning.

Here are the storm reports received by the SPC today. Red spots indicate tornado reports, blue spots indicate wind reports, and green spots indicate hail reports. Thankfully there hasnt been any today, but if there were SIG wind reports it would be a solid black square, and a SIG hail report would be a solid black triangle.

There have been a total of 19 tornado reports, 19 wind reports, and 27 hail reports, which makes a total of 65 reports.

[JLM]

There are currently no official severe weather threats for the next 8 days. This can change quickly, and it should be noted that the SPC has tagged Days 4-5 with "Predictability Too Low".

Take some certainty with the fact that severe weather is not expected for at least the next 3 days though.

[JLM]

The most recent update of the Day 4-8 outlook has the Upper Midwest and the Florida Peninsula as hotspots for possible severe weather during that time period. The Florida Peninsula potential will be caused by the likely to be tropical or subtropical system. However, there are no current risk zones right now.

Edited November 6, 2022 by JLM

[JohnAndSancho]

Buddy I hope someone gives you a scholarship for this, because you're clearly knowledgeable and passionate about climate and weather. 

[JLM]

3 hours ago, JohnAndSancho said:

Buddy I hope someone gives you a scholarship for this, because you're clearly knowledgeable and passionate about climate and weather. 

Haha thanks! Ive pretty much spent my whole life nerding out over weather.

When i was younger (in pre school) my parents said i would get up in front of the class and tell the weather forecast. I was always glued to the TV when big weather events were happening. My parents set up a meet with a local meteorologist (at the time in Nashville, TN), and that opened up a whole new world for me. Not only did i just meet the guy i had been watching on TV for my whole life up to that point, but he also pointed me towards the Storm Prediction Center and the National Weather Service. So i constantly used these sites and was always watching the radar.

When we moved to Florida in 2017, a new opportunity arose from the Gulf of Mexico, and it was Tropical Storm Cindy. I had never really heard of hurricane and tropical storms having lived in Tennessee. I figured that since we now lived in a hurricane prone area that it was time to really dive deep into how they work and why they do what they do. So now i am constantly glued to forecast models, not only looking for tropical cyclones but also severe weather events, winter weather events, and other things as well.

Nowadays its watching for when the next rain potential will be and when the next frost/freeze will be. I obviously, for some reason, am connected to nature in general. I strive to understand how weather works, and since my parents bought and planted 2 Queen Palms in 2019, ive been into palm trees. But my palm tree obsession technically started in 2014 on a vacation to Fort Walton Beach, FL. It was the common Sabal palmetto that really started it, i just didnt know it really until we actually owned palm trees 5 years later. I would be considered strange by my age group, but i honestly dont care. I just do what i love on a day to day basis.

[JohnAndSancho]

10 minutes ago, JLM said:

Haha thanks! Ive pretty much spent my whole life nerding out over weather.

When i was younger (in pre school) my parents said i would get up in front of the class and tell the weather forecast. I was always glued to the TV when big weather events were happening. My parents set up a meet with a local meteorologist (at the time in Nashville, TN), and that opened up a whole new world for me. Not only did i just meet the guy i had been watching on TV for my whole life up to that point, but he also pointed me towards the Storm Prediction Center and the National Weather Service. So i constantly used these sites and was always watching the radar.

When we moved to Florida in 2017, a new opportunity arose from the Gulf of Mexico, and it was Tropical Storm Cindy. I had never really heard of hurricane and tropical storms having lived in Tennessee. I figured that since we now lived in a hurricane prone area that it was time to really dive deep into how they work and why they do what they do. So now i am constantly glued to forecast models, not only looking for tropical cyclones but also severe weather events, winter weather events, and other things as well.

Nowadays its watching for when the next rain potential will be and when the next frost/freeze will be. I obviously, for some reason, am connected to nature in general. I strive to understand how weather works, and since my parents bought and planted 2 Queen Palms in 2019, ive been into palm trees. But my palm tree obsession technically started in 2014 on a vacation to Fort Walton Beach, FL. It was the common Sabal palmetto that really started it, i just didnt know it really until we actually owned palm trees 5 years later. I would be considered strange by my age group, but i honestly dont care. I just do what i love on a day to day basis.

Chase your dreams, homey. I know the area you're in pretty well, I grew up in Pensacola. I haven't been there since Hurricane Ivan but it's where I'm from. 

 

I've learned a lot from you, despite the fact that I cough up stuff older than you. Your future is bright, and as the world and the climate changes, we need people like you who care, pay attention, and are hungry for knowledge and willing to share what you discover. 

 

Anyway thank you for your efforts, and I hope you continue to chase your passions. Good vibes. 

[JLM]

1 hour ago, JohnAndSancho said:

Chase your dreams, homey. I know the area you're in pretty well, I grew up in Pensacola. I haven't been there since Hurricane Ivan but it's where I'm from. 

 

I've learned a lot from you, despite the fact that I cough up stuff older than you. Your future is bright, and as the world and the climate changes, we need people like you who care, pay attention, and are hungry for knowledge and willing to share what you discover. 

 

Anyway thank you for your efforts, and I hope you continue to chase your passions. Good vibes. 

The only thing that stumps me is the math. I may have to try over and over and over again as a lot of meteorologists have done before.

[JohnAndSancho]

15 hours ago, JLM said:

The only thing that stumps me is the math. I may have to try over and over and over again as a lot of meteorologists have done before.

Math can be taught. Passion can't. 

[Foxpalms]

@JLMSame thing here. I always used to read about tropical and Mediterranean climates and the palms were always my favourite plants. Seeing them on vacation as well always made it feel more tropical, or gave the area a nicer ambience. But it was only once I started owning palms that I really got into them. In my opinion lots of people especially in the UK become contempt with trying new species and resort to the same old hardy palms. Challenging you're self trying new palms that aren't supposed to grow in you're climate, designing different visually appealing ways to plant palms and collecting lots of different types of palms makes this an appealing hobby! In my case I've also had to research microclimate A LOT, to give my self the best chance at growing 9b and 10a plants.

Edited November 12, 2022 by Foxpalms

[JLM]

Gonna be quite honest, i forgot about this thread until this morning. I think its safe to say that the Fall/Winter severe weather season is kicking off. Yesterday we had a Marginal Risk across the Texas and Louisiana coast, it didnt really amount to anything so thats some good news. 

Today, we have a Marginal Risk with 2% tornado and 5% wind probabilities across the Texas coast.



For tomorrow, there is another Marginal Risk across portions of Louisiana, Mississippi, Alabama, and Florida with 2% tornado and 5% wind probabilities. If one of the scenarios listed by NWS Mobile plays out, it may not take much to see this get upgraded.



Day 3 has no severe potential, so now we change gears to the Day 4-8 outlook. 

Day 4 severe potential is too low, not expecting anything there. Day 5 does have an Enhanced Risk (Level 3/5) across portions of Louisiana, Arkansas, Mississippi, and Texas. A Slight Risk is in place for portions of Louisiana, Arkansas, Mississippi, Texas, Oklahoma, Tennessee, and Missouri. It is unknown what the tornado, wind, and hail probabilities are at this range, so we will just need to watch and see how this threat evolves. Do note that just because this threat is already at Level 3/5 on Day 5 does not mean that this will end up being a High Risk. 

Days 6 and 8 see the Predictability Too Low tag, which means that uncertainty is too high to place a 15% risk area right now, or the threat level just isnt high enough for a 15% risk.

[JLM]

I think ill throw the Excessive Rainfall Outlook on here when needed. The Excessive Rainfall Outlook basically gives the probability of heavy rainfall exceeding flash flood guidance, so in other words just the chance of flash flooding. This outlook has 4 categories compared to the SPC's 5 categories. Here are those categories:

Marginal - 5%
Slight - 15%
Moderate - 40%
High - 70%

Today there is a Moderate risk for flash flooding around the Houston metro area and points south. The Slight risk is much larger and covers a good chunk of eastern Texas today. Since the WPC is ahead of the SPC, ill post the outlook from the interactive map which is zoomable. Would be nice if the severe weather outlook was interactive...

[JLM]

Heres a quick early afternoon update.

Day 1 now features a Level 2 Slight Risk from SE Louisiana to the FL Panhandle. I mentioned yesterday that this may be a possibility, and it appears that models have trended in the direction of a more potent severe weather setup. The Marginal Risk has also been expanded northward. Below is a breakdown of the threats involved tonight:
Wind - 15% Slight
Tornado - 5% Slight
Hail - Below 5%; No Risk



Both Days 2 and 3 have no severe risk, so those will not be shown here. I will not post an image of Day 4 since it has not changed at all since yesterday. I mean literally, i compared the two outlooks and theres no difference. The Enhanced Risk has been maintained for portions of Louisiana, Mississippi, Arkansas, and Texas.


As of the time this post was made, the first tornado warning has officially been issued west of New Orleans, Louisiana for todays severe risk. Stay weather aware across the Gulf Coast tonight.

[JLM]

Quick afternoon update on the outlook.

Day 1: We have a Marginal Risk in 2 places today. One of them in eastern North Carolina and southeastern Virginia, this risk includes a low end tornado and wind threat. The other risk area is in portions of West Virginia, Maryland, and Pennsylvania, which includes a low end wind a hail threat.



Day 2: No risk area is present on Day 2.

Day 3: This is where things get interesting. The Enhanced Risk has been maintained, and it has expanded. The Enhanced Risk area now includes portions of Louisiana, Mississippi, Arkansas, Tennessee, and Missouri. A Slight Risk includes portions of Louisiana, Mississippi, Arkansas, Texas, Tennessee, Missouri, Kentucky, Illinois, and Indiana. A Marginal Risk includes portions of Louisiana, Mississippi, Alabama, Texas, Oklahoma, Arkansas, Missouri, Tennessee, Missouri, Kentucky, Indiana, and Illinois.

The SPC mentioned the possibility of increasing severe probabilities, the next category is Moderate. I would not be surprised to see this get into Moderate risk territory. This event looks to be highly tornado driven, and with the slow nature of the system, multiple rounds of severe storms may be possible.



Something else to note, the SPC is forecast a 10% chance for Significant severe storms. This could be wind or tornadoes or both. Tomorrow when the outlook changes to Day 2, we will get a detailed look at the wind, tornado, and hail threats.



I will provide a new update tomorrow morning.

[JLM]

As i suspected after looking at model data lastnight, the SPC has opted to upgrade to a Level 4/5 Moderate Risk across northeast Louisiana, northwest Mississippi, southeast Arkansas, and southwest Tennessee. Heres a breakdown of the threats at play here, but before that i will go ahead and show the Categorical Outlook.



Tornado Threat is what is driving this Moderate Risk. We have a 15% SIG risk for tornadoes in the Moderate Risk area. Surrounding this, there is a 10% SIG risk (Enhanced) across portions of Tennessee, Arkansas, Mississippi, and Louisiana. Overall, there is a marginal to slight tornado risk that includes the states of Louisiana, Mississippi, Alabama, Texas, Arkansas, Missouri, Tennessee, Kentucky, Illinois, and Indiana.

A potentially significant tornado outbreak could occur tomorrow, stay weather aware.



The Wind threat is kept at the Enhanced Risk level, as this event looks to feature mostly discrete supercells. There is an area where significant wind could be possible across Mississippi.



The Hail threat is even lower at the Slight Risk level. This event is not really expected to be a big hail driven event, and as such the risk is lower. Some large hail could be possible, but nothing too significant is expected.




Now we transition to the Day 3 Outlook, which currently features a Marginal Risk. This is a pretty large risk area, and the SPC has noted that its hard to pinpoint any areas of higher severe risk due to differences in model outputs. I would say that the event might transition to more of a linear storm mode, and at that point damaging winds becomes the primary threat. By tomorrow, we will hopefully have a better idea of where the highest severe risk might be. Until then, just know that a Marginal severe risk exists in portions of Louisiana, Mississippi, Alabama, Florida, Georgia, South Carolina, North Carolina, Tennessee, Kentucky, Virginia, West Virginia, and Maryland on Wednesday.

[JLM]

Major changes have been made today on the Day 2 Outlook. All the risk levels remain the same, but the areas these risks cover has expanded.

The biggest changes is the Marginal and Slight Risk zones have been significantly expanded east. The Slight Risk now includes a small portion of Florida, and covers most of western Alabama.

Another change is the Moderate Risk has been expanded a little bit, covering more of northern Mississippi.

And lastly, since this threat appears to be mostly discrete supercells as i mentioned earlier today, the SPC has opted to drop the SIG risk for the wind threat.

Here are the updated images for the Categorical, Tornado, Wind, and Hail outlooks. I decided to add the table that displays square miles of the risk area, the population in the risk area, and the bigger population centers within the risk area.

Categorical:




Tornado:




Wind:




Hail:





If you live in these areas, it is EXTREMELY important that you have a way to receive alerts tomorrow. Even if you are in the Marginal Risk area, tornadoes and damaging winds may still occur. 

[JLM]

I will not have a full update until this afternoon, and by then this event may already be underway.

Have a way to get warnings if you live in ANY risk zone. 

[JLM]

Wont be able to do a full update until later tonight, but the middle of next week looks to have big severe weather days. There is an Enhanced Risk already for Tuesday, and a Slight Risk that continues into Wednesday across the central Gulf Coast states.

[JLM]

Im just gonna jump straight to Day 3, as the update for tomorrow just came out and the severe threat was dropped for tomorrow (12/11/22).

Day 3 features a Marginal Risk over portions of Oklahoma and Texas. SPC noting that the highest risk looks to be hail, a low end wind and tornado threat may be possible but doesnt look too likely at the moment. We will see what the new model data is looking like, and we will see if the severe potential increases or not.




Day 4 has everyones attention right now, or at least the attention of those who follow this stuff consistently. There is an Enhanced Risk in place for portions of Louisiana, Mississippi, Texas, and Arkansas. A Slight Risk is in place for the rest of Louisiana, a decent chunk of Arkansas, Mississippi, Texas, and Oklahoma. A small bit of Tennessee is also included. This is looking to be an all hazards event with damaging wind, tornadoes, and hail all possible. Tuesday needs to be watched closely.




Moving on to Day 5, we see an extension of the Slight Risk from Day 4 into Day 5 across portions of Louisiana, Mississippi, Alabama, and Florida. Wednesday could also present an all hazard threat, but it shouldnt be as pronounced as Tuesday. Gonna watch to see if Day 5 has the potential to be upgraded or not, this is heavily dependent on model trends as forecast models are having major timing and evolution differences from run to run. 




Day 6 Thursday does not currently have a risk area outlined, mainly due to huge model differences. SPC has mentioned the possibility of a more localized severe threat across Florida for Day 6. Model uncertainty is too high to include a 15% risk area, and also its still unknown whether or not a 15% risk will be warranted. Just know that if all the pieces come together, a lower end severe threat may evolve on Thursday.
For the rest of the Day 4-8 period, SPC has included the Predictability too low tag.

[JLM]

This multi day event just got longer. Ill be putting Day 1-4 on here, because this will end up being a 4 day long severe weather event across the central and southern US.

Day 1 has just been upgraded to a Slight Risk overnight for portions of Oklahoma, Texas, and Kansas. The Marginal Risk is in place for portions of Oklahoma, Texas, Kansas, Colorado, and Nebraska. Yes this risk area has shifted and expanded quite a bit from the last update.



The tornado threat with today's risk is part of whats driving our Slight Risk today. The tornado risk zone is a little bit smaller than the entire Slight risk area. An isolated tornado or two is possible today, especially within the brown area.



The wind threat is the other factor in the Slight risk today. Damaging winds are possible today, especially in the yellow area.



The hail threat is pretty low end for todays event. Some large hail is possible, but not very likely. If any hail occurs today, i would generally expect it to be small hail.



On to Day 2 now, which still features the Enhanced Risk for portions of Louisiana, Texas, and Mississippi. A Slight Risk remains for the rest of Louisiana, portions of Texas, Arkansas, and Mississippi. The Marginal Risk is in place for portions of Texas, Oklahoma, Arkansas, Mississippi, and Alabama.



The tornado threat is part of whats driving the Enhanced Risk zone. We see there is a 10% tornado risk zone, and you also see that black hatched area over it. This means that theres a decent chance for tornadoes, some of which could be significant (EF2+). 



The Wind threat is the other driving factor behind the Enhanced Risk. The red area should be the focus for damaging winds, but damaging winds are still possible across the entire risk area (Marginal to Enhanced).



Lastly, the hail risk. The hail risk is lower than both wind and tornado threats at this point, but large hail is definitely a possibility, especially across the yellow area.



On to Day 3. There is a Slight Risk present for portions of Louisiana, Mississippi, Alabama, Florida, and Georgia. A Marginal risk is present for portions of the same states listed for the Slight risk. A few isolated tornadoes, damaging wind, and some hail may be possible across the entire risk area.



Moving on to Day 4, this is where it gets interesting. SPC has added a new Slight Risk area for portions of Florida, Georgia, and a tiny bit of South Carolina. This looks to be a tornado and wind threat, but specifics will be nailed down in a couple of days.




It is important to make sure you have a way to get warnings if you live in any of these risk areas this week.

[JLM]

Another underlying threat with this severe event, especially for Days 2 and 3, is flash flooding. This line will likely be slow moving, and with high rain rates, it will likely dump a widespread 2+ inches of rainfall, with higher totals where training cells occur.

[JLM]

Heres the update for today, there may be another this afternoon as today and tomorrow will be very active.

Day 1 features an Enhanced Risk still, which has been maintained since this event was on the Day 6 outlook i think. SPC has done a fantastic job this year. Anyways, the Enhanced Risk area did expand a bit to include more of Mississippi and Louisiana. The Slight Risk has been expanded significantly westward to include the activity that is already ongoing right now as i type this. 



The tornado threat has expanded, which is cause for the ENH risk expansion. There is a 10% chance for tornadoes in the yellow zone, and a 10% chance for significant tornadoes in the black hatched zone.



The wind threat has also expanded. It remains at 30%. The highest probability for damaging winds exists in the red area, but remember that damaging winds can still occur in the yellow and brown areas.



The hail threat has not changed much since yesterday, so to save space i will not post it. The low end hail risk has expanded northeast into northern Mississippi.

Moving on to Day 2. Tomorrow also looks to be quite active. SPC has upgraded to an Enhanced Risk overnight for portions of Louisiana, Mississippi, Alabama, and Florida. The severe risk in general has been expanded a bit north compared to yesterdays outlook.



The tornado threat is whats had the most increase in my opinion. There is an increasing likelihood of supercell activity out ahead of the main line, and possibily embeded meso cyclones in the main line which could lead to tornadoes. There is a 10% chance for tornadoes in the yellow area, and a 10% chance for significant tornadoes in the black hatched area.



The wind threat has also increased. The highest probability of damaging straight line winds will be in the red zone, but once again damaging winds can occur in all the zones.



And lastly, the hail threat. It is pretty low, meaning that hail is possible but not likely.



Now for Day 3. The Slight Risk has been maintained for portions of Florida and Georgia, and has been expanded further north to include more of coastal South Carolina. Details on tornado, wind, or hail will come tomorrow (These risk hazards are not done for Day 3 outlooks)



Once again, another underlying threat with this event is the flash flood potential. 
This is the outlook for today. There is a Slight Risk on both Days 1 and 2. Flash flooding may occur where training of storms sets up.

Day 1



Day 2




It is very important to have a way to get warnings over the next few days.

[JLM]

So far, 7 injuries and 2 deaths have occurred because of tornadoes and damaging winds from this event. Hopefully no more injuries or deaths will occur today or tonight.

[JLM]

Today's risk has been upgraded to Moderate, but that doesnt matter. What matters is that over 20 possible tornadoes have been reported today in Mississippi and Louisiana, and we still have a long time to go before the tornado risk calms down some.

[JLM]

Ok, since the last update, there really hasnt been much severe risk. Yesterday there was a Marginal Risk, and theres also one today. The main focus though is the Day 4-8 outlook which is lit up again.

Day 4 holds an Enhanced Risk (3/5) for portions of Texas, Louisiana, Arkansas, and Mississippi. A Slight Risk (2/5) includes portions of Texas, Louisiana, Mississippi, Oklahoma, Arkansas, Missouri, Tennessee, Kentucky, Illinois, and Indiana. This could be an all hazards event, including flash flooding.



Day 5 holds a Slight Risk (2/5) for portions of Louisiana, Mississippi, Alabama, Florida, and Georgia. This too could be an all hazards event including a flash flood threat.



This is unrelated to severe weather, but here is the rainfall forecast for the next 7 days. This is why there is a flash flood threat present. Totals of 4-5 inches is pretty widespread across portions of coastal Mississippi, Alabama, and portions of northern Georgia and into South Carolina. There are swaths of 5-7 inch totals across coastal Mississippi, Alabama, and the Florida Panhandle, with another in east central Alabama, and another in northern Georgia, South Carolina, and southwestern North Carolina.

I figure since i do have this map here, why not mention those really bright colors in California? Yes, they are getting rain! Some spots in the mountains could get 15 inches or more of rainfall. Otherwise, widespread totals of 5-10 inches is expected along the coast for most of the state.

[JLM]

Im gonna be honest, i forgot about this thread again.

Yesterday was not looking like it was going to be a bad day, the models were not too happy with the setup. It was that way until we got to Wednesday night, and things began to ramp up quickly. Models still did not grasp the magnitude of yesterdays event. SPC did issue an Enhanced Risk for portions of Alabama and Georgia. Several tornadoes touched down across the state of Alabama, some hitting large population centers like Selma, AL, where major damage occurred (a house was literally picked up and dropped on the house next to it). These storms continued into Georgia where more populated areas were hit. As of now ive seen that 7 deaths have been confirmed. 6 in Autauga County, Alabama and 1 in Butts County, Georgia. In total there were 35 tornado reports across Alabama and Georgia with a few in Kentucky. This does not mean there were 35 tornadoes, but the NWS will be doing surveys over the next several days to confirm how many tornadoes touched down and how strong they were. 

On top of the tornadoes, there were also many instances of damaging winds. Sometimes these wind reports turn into tornado reports after NWS surveys, but for now there have been 227 damaging wind reports and 1 major report out of South Carolina where a wind gust of 75 mph was observed. There were also 24 hail reports spread out across multiple states.

[JLM]

Looking to the future, there are currently no outlook areas to speak of, although the SPC is watching the south during the Day 4-8 period. Uncertainty is too high for an outlooked area at this time.

[JLM]

Any possible threat in the Day 4-8 period does not look to be bad, considering instability currently looks limited. Dont let this fool you though, Thursday was not looking to be very favorable because of a lack of instability on forecast models. Below is the current numbers from the NWS on the number of tornadoes from Thursday:

**All numbers are considered PRELEMINARY**
EFU (Undetermined) - 0
EF0 (65-85 mph) - 6
EF1 (86-110 mph) - 15
EF2 (111-135 mph) - 8
EF3 (136-165mph) - 2
EF4 (166-200 mph) - 0
EF5 (>200 mph) - 0
Total: 31

Here's the numbers for filtered storm reports by the SPC:

**All numbers are considered PRELEMINARY**
Tornado Reports: 45
Wind Reports: 201/1
Hail Reports: 20/0
Total: 266

Unfiltered:
Tornado Reports: 55
Wind Reports: 302/1
Hail Reports: 27/0
Total: 384

The difference between filtered and unfiltered is filtered picks out reports that are made in very close proximity to each other or within a certain time period of each other (this is a very small window of time). Unfiltered is all of the reports submitted without any edits besides trashing duplicates.

It should be noted that the NWS will likely continue doing surveys through the weekend, so these numbers will change.

[JLM]

Here is the SPC Day 3 Severe Weather Outlook featuring a Slight Risk for portions of Texas, Louisiana, Arkansas, and Mississippi. I added city labels to the map.

The main threat here will be damaging winds, but if any cells can form in the warm sector then all hazards would be possible including damaging winds, tornadoes, and large hail.

[JLM]

A quick update tonight:

SPC has portions of Florida, Georgia, and South Carolina in a Level 1/5 Marginal risk zone for Sunday. They are noting that damaging winds gusts and isolated tornadoes may be possible, especially along the Florida Panhandle where instability may be more conducive.



Skipping forward to Day 5, next Tuesday into Tuesday night. This event is uptrending in model data, and at this point the only way i see that the SPC does not upgrade this to an Enhanced Risk tonight is if they want to see this trend persist longer. The setup for Tuesday is already looking quite potent, but will need to monitor model trends to see if this changes. Something to note is that global models tend to underdo instability, especially in the long range. SPC has outlined portions of Louisiana, Mississippi, Alabama, and Florida under a Level 2/5 Slight Risk. SPC noting that damaging winds and tornadoes may be possible, but NWS has said that all hazards are possible including large hail. 

[JLM]

Early morning update (1/24/23):

A potentially significant severe weather event may occur across the western and central Gulf Coast later today into early Wednesday morning. An Enhanced Risk has been issued from Victoria, TX to Destin, FL. 



The tornado threat is whats catching everyones attention right now. SPC has issued a 10% tornado risk, with the hatched area residing here as well. Tornadoes, some strong and maybe even long track, may occur tonight anywhere from the Texas coast to the Florida panhandle. This risk includes some major cities like Pasadena TX, Galveston TX, New Orleans LA, Baton Rouge LA, Mobile AL, and Pensacola FL. All ingredients are there to support the development of tornadoes, especially if we get any discrete supercells out ahead of the main line.



Now for the Wind threat, which is more elevated than usual because of the ripping 500 mb jet reaching 100-110 knots, and the 850 mb level reaching 70-75 knots! Thats insanely strong. This will also lead to high wind gusts outside of thunderstorms as well. The wind threat will likely increase as the system moves east, as a squall line is expected to form which will pose a risk for damaging straight line winds. A 30% wind risk zone has been added from southeast Louisiana to the Florida panhandle.



The hail threat is there, but its lower than the other threats. Hail will be much more supported over the Texas coast area of the risk zone. The SPC has outlined the Texas coast in a 15% (Slight) risk for large hail. Hail shouldnt be too crazy, but small hail seems more likely and would be possible from Texas to Alabama. The hail threat will gradually drop with eastward extent.



Now to talk about another hazard, which is not related to severe thunderstorms. High Wind Warnings have been issued across the northern Gulf Coast from far southeast Texas to the Florida panhandle. Sustained winds are expected to be anywhere between 25-40 mph with winds gusting between 50-60 mph. This is absolute insanity. The power outage risk BEFORE the storms is significantly higher than with other events, so its extremely important to have MULTIPLE ways to get severe alerts. At least 2 of those ways should be battery operated and should be fully charged before the winds pick up. You need to prepare your yard as if you were preparing for a tropical storm, securing any loose objects which will easily blow away today like trampolines (i can almost guarantee you someone is gonna lose a trampoline today), trash cans, and patio furniture, etc. The list goes on.

STAY WEATHER AWARE ON THE GULF COAST TODAY AND TONIGHT!!

[JLM]

The severe weather threat over Mississippi earlier this week snuck up on me. I was unavailable to make an update when the Enhanced Risk was issued. Luckily it did not pan out the way it was forecast to. 

Lets look into the future, as next week looks pretty dicey across the south. Below will be the Day 6 and Day 7 outlooks by the SPC. This is still very far out and will certainly shift around and change as time goes on. We still have 3 days before at least one of these outlooks makes it to Day 3, we may not see a ton of change between now and then but it must be watched as models can/will shift things around that could cause different outcomes. Both Day 6 and Day 7 may be an all hazards event, but its just too early to tell what hazards may be present.

The Day 6 Outlook includes portions of Texas, Louisiana, Mississippi, Arkansas, Missouri, and Tennessee.



The Day 7 Outlook includes portions of Mississippi, Alabama, Tennessee, Georgia, Florida, and a very tiny portion of North Carolina. Some stats on this, this is North Carolina's first time being included in a Day 7 Slight Risk in February. 

[JLM]

Major changes have occurred with both days.

The Day 5 Outlook area has been expanded west further into Texas and Oklahoma.

The Day 6 Outlook area has been significantly expanded as far north as Indiana and west to the Mississippi River on the southern end.

I want to point out something more important at the moment though, and thats the Day 1 Outlook which features a Slight Risk for portions of Northeast FL.

The threats today are damaging winds and isolated tornadoes.




Now for the Day 5 Outlook:



Day 6 Outlook:



Some notes about the Day 5 Outlook, SPC has mentioned an upgrade to Enhanced in future outlooks. Day 5 looks quite concerning, all hazards will be possible. Day 6 is also concerning, but it doesnt look quite as favorable as Day 5. Regardless, both days may bring a severe threat to a very large area of the US next week. Now is the time to get ready. Have a plan on where to go should warnings be issued, make sure you have an emergency kit which includes food, water, flashlights, batteries, etc. Find football or baseball helmets to protect your head if a tornado warning is issued. Also, find a whistle or something to make a loud noise should you be trapped. Im not saying we will have an outbreak of tornadoes, but an emergency kit is always a good thing to have because you just never know.

[GottmitAlex]

They're calling for a cold snap between now and Wednesday. (San Diego/TJ region)

[JLM]

Today could be a not good day across portions of the south. An Enhanced Risk is in place from Alabama/Mississippi to Kentucky with damaging winds and tornadoes being the primary threats. A Slight Risk extends from the Gulf Coast to Indiana/Ohio, and a Marginal Risk extends from the Gulf Coast to the Great Lakes. The blue hatched zone on the below graphic is where the highest tornado potential exists today, some tornadoes may be strong. The northern end of the Enhanced Risk zone is where damaging winds is the primary threat with isolated tornadoes being possible. SPC has noted that a northward expansion of the SIG tornado probabilities is possible, and a Moderate Risk may also be introduced later today if necessary. Thunderstorms have already began over portions of Louisiana and Mississippi and could pose a tornado risk later today as they move northeast.

[JLM]

A significant severe weather event may occur tomorrow across portions of Oklahoma, where a Moderate (4/5) Risk was issued earlier today. Depending on what the next update holds, there may or may not be a new update in the next hour or two.

Here is the Convective Outlook:


The wind threat is the cause for the 4/5 risk zone. A 45% significant risk of damaging winds is in place. Damaging winds is by far the main threat, followed by large hail. There may also be an isolated tornado embedded in the expected line of storms.

[JLM]

Alright, we are about to be headed into an active period of severe weather across the US, so pay close attention to the forecast over the next week. 

We start off with today, which holds a Moderate Risk (Level 4/5) for a decent chunk of Oklahoma. The risk area expanded east overnight. With this, the tornado threat also increased on the far western side of the MDT risk zone. The reason for this is because storms are expected to start out as supercells, then build into a squall line. The tornado threat will be maximized before the storms turn linear. Once storms turn linear, a significant risk for damaging winds will take over with a threat for embedded QLCS tornadoes. The damaging wind threat will continue into portions of Kansas, Missouri, and Arkansas this evening and overnight tonight.

Categorical Outlook:



Wind Threat:



Tornado Threat:



Hail Threat:




Now looking at tomorrow, a Slight Risk is in place across portions of Illinois, Indiana, Ohio, and Kentucky. The main threat will be damaging winds with a low end tornado threat also present.

Categorical Outlook:



Now we skip ahead to Day 5 Thursday and Day 6 Friday. SPC mentions the potential for "A widespread outbreak of severe weather" (yes, this is in the SPC discussion) across the lower Mississippi Valley and central Gulf Coast states Thursday evening into Thursday night. SPC mentioning all hazards possible with Damaging winds, tornadoes, and hail all being possible.

Day 5 Outlook:



The severe threat is expected to continue, with SPC mentioning that all hazards threat may continue into the southeast for Friday.

Day 6 Outlook:



I should mention that the Day 5 and 6 outlook areas were introduced lastnight, so Day 5 went straight from "Predictability Too Low" to a Level 3 Enhanced Risk. I have not seen that happen before.
It is EXTREMELY important that you stay weather aware today across Texas, Oklahoma, Kansas, Arkansas, and Missouri. Folks in Texas, Oklahoma, Louisiana, Arkansas, Tennessee, Mississippi, Alabama, Florida, Georgia, South Carolina, and North Carolina all need to monitor the forecast for the end of the week. Now is the time to get ready for the possibility of severe weather late this week.

[JLM]

SPC just issued a new outlook for today, and they are now explicitly forecasting a derecho causing swaths of significant damaging winds of 80-110 mph across portions of Oklahoma. To put this into perspective, this would be the equivalent of a Category 1-2 hurricane. 

[kinzyjr]

4 hours ago, JLM said:

SPC just issued a new outlook for today, and they are now explicitly forecasting a derecho causing swaths of significant damaging winds of 80-110 mph across portions of Oklahoma. To put this into perspective, this would be the equivalent of a Category 1-2 hurricane. 

Hope @Ben OK and the other Oklahoma folk on the forum do alright.

[JLM]

50 minutes ago, kinzyjr said:

Hope @Ben OK and the other Oklahoma folk on the forum do alright.

Portions of OK, TX, and KS were put under a tornado watch with the following hazards expected:
- A few tornadoes likely
- Scattered hail up to tennis ball size possible
- Widespread wind gusts up to 100 mph