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Severe Weather 2025

Looks like a pretty solid cold core setup in IL and vicinity tomorrow. Rather intense deep layer cyclone with 50s dewpoints ahead of an arcing boundary. Wouldn't be surprised to see a few tornadoes with low-topped supercells. The 18z NAM 3 km, 18z HRRR, and 15z RAP all agree with this notion.
 
andyhb said:
Looks like a pretty solid cold core setup in IL and vicinity tomorrow. Rather intense deep layer cyclone with 50s dewpoints ahead of an arcing boundary. Wouldn't be surprised to see a few tornadoes with low-topped supercells. The 18z NAM 3 km, 18z HRRR, and 15z RAP all agree with this notion.
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Yeah, good chance I'll be out after work tomorrow.
 
Kds86z said:
No mention of supercells yet..
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Even though it’s eye brow raising seeing the early forecast for sure, they won’t wanna be using too many extreme words yet. It is still quite a few days out. By about Thursday we should have a better idea of how it could unfold.
 
Fred Gossage said:
It's a simple level math calculation you can work out to always get the TNI value for any daily, monthly, weekly, or archived past ENSO SST anomaly readings you come across. It is simply the SSTA of ENSO Region 1+2 minus ENSO Region 4. (ENSO 1+2) - (ENSO 4). When ENSO Region 4 (the west) is less warm than ENSO Region 1+2 (the east, up against the South American coast), even if it's above average but less above average than ENSO 1+2, the TNI is positive. This happens most often either entering an El Nino or exiting a La Nina. When the eastern ENSO area is less warm than the western ENSO area, the TNI is negative. This is most common when an east-based La Nina is starting to form.

Today's daily CDAS SSTA data shows ENSO 1+2 is at +1.097C, and ENSO 4 is at -0.673. That gives a daily TNI, based on the CDAS data, of +TNI. That is high-end positive. At one point within the past 7-10 days, it peaked at over +2.5, and it was the highest daily value I'd ever seen in real-time since the research paper linking it to tornado outbreaks came out after the 2011 super outbreak. The TNI has come down a little since then, despite still being high-end positive and excruciatingly favorable for big league trouble because of the global propagation of the MJO. You'll see it waffle as those things happen and as the low-level trade winds respond to the MJO forcing on a daily and weekly basis. However, as the MJO continues to propagate, the ENSO 1+2 cooling and ENSO 4 warming have both halted and begun reversing, halting and likely soon reversing that little bit of a drop that's happened to the TNI (which, despite that drop, is still into the high-end positive range).

Matt G and I both feel like, instead of the configuration driving the pattern, it is a dummy light for the pattern and a positive value configuration is put into place by things like the MJO and other factors that drive the large scale weather patterns across the globe. It's all directly linked, but the TNI is likely the equivalent of using a TVS icon or the Baron shear markers and SCITs to identify a tornado signature on radar instead of spotting the couplet in the raw velocity data itself.
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What you and @Matt Grantham have done is so interesting. At some point, in one of my future projects, I'm planning to go through the MJO (like I did with the Atlantic hurricane seasons since 1975) and list all the severe weather events that occur in each phase of the MJO (1, 2, 3, 4, 5, 6, 7, 8, and the NULL). That should prove very fruitful. I got the idea after I finished the Atlantic MJO tropical spreadsheet.
 
North MS Tornado Stats (updated to include Saturday tornadoes):

671 total tornadoes
179 total AM tornadoes
491 total PM tornadoes
Highest TOR count by county is Monroe now at 56 (4.7%)
2nd highest TOR count is Lee at 55 (4.6%)
 
JPWX said:
North MS Tornado Stats (updated to include Saturday tornadoes):

671 total tornadoes
179 total AM tornadoes
491 total PM tornadoes
Highest TOR count by county is Monroe now at 56 (4.7%)
2nd highest TOR count is Lee at 55 (4.6%)
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Interesting stats @JPWX

Do you know if Dr Coleman & Dr Knupp over at UAH have done any studies on topography and tornado occurrence related to Mississippi? I know they do a lot with Alabama, and I could have sworn I read an article once where they said the terrain on the Alabama/Mississippi line channeled low level winds that was favorable to tornado genesis.
 
ColdFront said:
Interesting stats @JPWX

Do you know if Dr Coleman & Dr Knupp over at UAH have done any studies on topography and tornado occurrence related to Mississippi? I know they do a lot with Alabama, and I could have sworn I read an article once where they said the terrain on the Alabama/Mississippi line channeled low level winds that was favorable to tornado genesis.
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I honestly don't know. I know studies on this have been done in Alabama
 
WaryWarren said:
When you see Reed or Andy Cheesehead roll through your burg, you know you have to batten down the hatches.
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The Dominator rolled by in front of me in Winona, MS this past Saturday. It was too fast for me to grab my camera and get a pic. I thought about following, but decided otherwise.
 
1000078441.gif
Tornado driven 10% hatched Enhanced Risk. Contemplating canceling my appointment I had scheduled for today to go out chasing in Illinois.
1000078440.gif


Discussion: "A rapidly changing environment is forecast across Illinois today. Extensive cloudcover is expected across the state for much of the day as low-level moisture streams north within a narrow corridor ahead of the cold front. However, by mid to late afternoon, some
clearing is expected which may allow for some brief heating and destabilization across central Illinois. In fact, the HRRR shows what appears to be a dryline by mid afternoon. Mid-level temperatures will be very cold (-22C at 500mb and -4C at 700mb) which will allow for rapid destabilization with only slight heating.
Once destabilization begins ahead of the cold front/dry line, expect thunderstorm development. The wind profile across central and northern Illinois will support supercells, but the intensity of these supercells will be modulated by the instability. 250-500 J/kg MLCAPE will likely be sufficient for supercells capable of all
severe weather hazards. However, if greater destabilization occurs, such as shown by the 00Z HRRR/ 03Z RAP, an even more volatile environment would be present. 56-57F dewpoints would support 1000+ J/kg MLCAPE which is very significant in the low-topped environment
with an EL below 30kft. HRRR/RAP soundings show STP values around 2-3 with very favorable low-level hodograph shapes. Therefore, in the higher instability scenario, multiple tornadic supercells would be possible with the potential for strong (EF2+) tornadoes. While uncertainties remain regarding dewpoints and the amount of clearing/heating along/ahead of the front, an enhanced risk upgrade seems prudent given the expectation for several supercells capable
of all hazards and the conditional potential for a more volatile environment."
 
US_Highway15 said:
View attachment 36753
Tornado driven 10% hatched Enhanced Risk. Contemplating canceling my appointment I had scheduled for today to go out chasing in Illinois.
View attachment 36754


Discussion: "A rapidly changing environment is forecast across Illinois today. Extensive cloudcover is expected across the state for much of the day as low-level moisture streams north within a narrow corridor ahead of the cold front. However, by mid to late afternoon, some
clearing is expected which may allow for some brief heating and destabilization across central Illinois. In fact, the HRRR shows what appears to be a dryline by mid afternoon. Mid-level temperatures will be very cold (-22C at 500mb and -4C at 700mb) which will allow for rapid destabilization with only slight heating.
Once destabilization begins ahead of the cold front/dry line, expect thunderstorm development. The wind profile across central and northern Illinois will support supercells, but the intensity of these supercells will be modulated by the instability. 250-500 J/kg MLCAPE will likely be sufficient for supercells capable of all
severe weather hazards. However, if greater destabilization occurs, such as shown by the 00Z HRRR/ 03Z RAP, an even more volatile environment would be present. 56-57F dewpoints would support 1000+ J/kg MLCAPE which is very significant in the low-topped environment
with an EL below 30kft. HRRR/RAP soundings show STP values around 2-3 with very favorable low-level hodograph shapes. Therefore, in the higher instability scenario, multiple tornadic supercells would be possible with the potential for strong (EF2+) tornadoes. While uncertainties remain regarding dewpoints and the amount of clearing/heating along/ahead of the front, an enhanced risk upgrade seems prudent given the expectation for several supercells capable
of all hazards and the conditional potential for a more volatile environment."
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Dang, from a day 2 marginal risk to a day 1 10% hatched.
 
US_Highway15 said:
View attachment 36753
Tornado driven 10% hatched Enhanced Risk. Contemplating canceling my appointment I had scheduled for today to go out chasing in Illinois.
View attachment 36754


Discussion: "A rapidly changing environment is forecast across Illinois today. Extensive cloudcover is expected across the state for much of the day as low-level moisture streams north within a narrow corridor ahead of the cold front. However, by mid to late afternoon, some
clearing is expected which may allow for some brief heating and destabilization across central Illinois. In fact, the HRRR shows what appears to be a dryline by mid afternoon. Mid-level temperatures will be very cold (-22C at 500mb and -4C at 700mb) which will allow for rapid destabilization with only slight heating.
Once destabilization begins ahead of the cold front/dry line, expect thunderstorm development. The wind profile across central and northern Illinois will support supercells, but the intensity of these supercells will be modulated by the instability. 250-500 J/kg MLCAPE will likely be sufficient for supercells capable of all
severe weather hazards. However, if greater destabilization occurs, such as shown by the 00Z HRRR/ 03Z RAP, an even more volatile environment would be present. 56-57F dewpoints would support 1000+ J/kg MLCAPE which is very significant in the low-topped environment
with an EL below 30kft. HRRR/RAP soundings show STP values around 2-3 with very favorable low-level hodograph shapes. Therefore, in the higher instability scenario, multiple tornadic supercells would be possible with the potential for strong (EF2+) tornadoes. While uncertainties remain regarding dewpoints and the amount of clearing/heating along/ahead of the front, an enhanced risk upgrade seems prudent given the expectation for several supercells capable
of all hazards and the conditional potential for a more volatile environment."
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What the…..
 
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