Rotating supercells could produce hail and a few tornadoes in Texas/Oklahoma before transitioning into windy lines/clusters. Some of the hail may be large and damaging.
Meteorologist @matthewcappucci.bsky.social has a severe weather briefing.
An UPGRADED tornado risk has occurred in northern Illinois and northwest Indiana. If you live between Galesburg, Peoria, Kankakee, Bloomington, Champaign, Rochester or Renssalaer, Indiana, please review your severe weather plan ASAP!
NEW: A Level 4 out of 5 severe weather risk has been introduced in the red zone across portions of north central Illinois and adjacent western Indiana.
Several tornadoes, including a couple strong and/or long -track, are expected.
JUST IN: The SPC has upgraded parts of Illinois and Indiana to a Moderate Risk (4/5, red) with a 15% 'CIG2' hatch area.
This means storms have the potential to produce EF3+ tornadoes.
Take today very seriously.
Rotating supercells will form in Illinois/Indiana this evening. Where temperatures are warm, significant tornadoes are possible. Where they’re cool, large, damaging hail could occur.
@matthewcappucci.bsky.social has a severe weather briefing.
myradar.com/videos/6388
NEW: SPC is now cautioning that INTENSE tornadoes (EF3+) are possible THIS EVENING in northern Illinois/Indiana/southern Michigan!
Confidence is increasing in the potential for supercells to ride the warm front eastwards, gobbling up ample low-level spin and becoming dangerously problematic.
For now, hail risk is greatest near the Rio Grande Valley and in central Texas.
The big wildcard? Will storms remain as lone, discrete and isolated supercells fully able to tap into the favorable atmospheric parameters? Or will they merge into windy lines and clusters more quickly, cutting back on hail risk? That remains to be seen.
That's where thunderstorms, initially forming to the west along a diffuse dryline boundary, will work east into greater moisture. That will help them to strengthen.
The data comes directly from human forecasters at the National Weather Service Storm Prediction Center.
The greatest risk of large, destructive hail – perhaps over 3 inches in diameter – is over the Edwards Plateau and maybe even into central Texas west of Dallas-Fort Worth.
TEXAS-SIZED HAIL possible THIS EVENING (Tuesday, March 10)! This map does not show the likelihood of hail, but rather the MAX SIZE *if* rotating thunderstorms become established and can take advantage of the environment.
Warm fronts tend to impart extra low-level helicity, or twist, on storms, bolstering rotation.
That, in tandem with an environment already supportive of spinning storms, supports several intense, long-track supercells in Illinois/Indiana with hail or tornadoes.
That's why the thunder will reverberate between the ground and the air at 5,000 feet, causing an "echoing" of sorts.
Also, the thunder in Chicago may be EXTRA loud. Why? There will be warm air about a mile up riding atop the shallow cool air mass. That will act as a ceiling to the lower atmosphere for sound to bounce off.
To the north, the surface will be cooler. Thunderstorms will be elevated and ride atop a shallow cool layer. Chicago-area storms will be mostly hailers.
In central Illinois and northwest/north central Indiana, it will be warm, with temperatures in the mid to upper 70s. That will support surface-based storms, or those that inhale warm, humid air near the surface. That, in turn, will support the threat of tornadoes.
Today (March 10) will feature a VERY dramatic difference in only a few miles if you live near the shores of Lake Michigan. And if you live in Chicago, there is the CHANCE of some big hail.
Models struggle to simulate these nitpicky, fine-scale "mesoscale" details until even a few hours before. As such, if you live in central Illinois or northwest Indiana, please stay weather-aware today.
Moreover, we still aren't sure if the boundary will lift north a bit and act as a warm front, or if it will crash south a bit and allow cold air to "undercut" rotating thunderstorms in the warm sector.
The big wildcard: do storms stay on the warm side of the boundary?
If they slip onto the cool side, they lose their tornado risk and mainly produce hail.
TUESDAY, March 10 – IF a storm can become established on the south side of a stalled boundary in central Illinois, and root itself in warm air, oof... the environment would be VERY conducive to powerhouse tornadoes... perhaps in the EF2 to EF3+ range.
To the north of the boundary, storms will be elevated, or riding atop a shallow cool layer near the surface – especially where the chilly waters of Lake Michigan cool the nearby air. That's why hail is the main concern.
Those that remain on the warm side over central Illinois and perhaps northwest Indiana (away from the lake) could produce a STRONG tornado or two (EF2+). Hail up to baseball size is also possible.
Amid an environment with plenty of thunderstorm fuel and ample shear (changing winds with height), rotating thunderstorms will probably form on BOTH sides of the boundary.
It all comes down to the position of the stalled stationary/warm front. To the south, it will be warm and humid. To the north, cooler and drier.
TODAY, March 10 should feature the risk of significant severe weather – including perhaps a few strong tornadoes and large, damaging hail – in Illinois and perhaps Indiana.
UPDATE: The SPC has upgraded a portion of Texas to an Enhanced risk (3/5, orange) for severe weather on Tuesday.
As @matthewcappucci.bsky.social mentioned below, there’s a sneaky shot at some strong tornadoes (EF2+) around the DFW metroplex.
TOMORROW: A broad, multi-faceted severe weather event is likely Tuesday from the Midwest to the Rio Grande.
Damaging gusts, very large hail and a couple tornadoes, some significant, are expected.
Senior meteorologist @matthewcappucci.bsky.social has a severe weather briefing.
A few supercells are possible across parts of Arkansas, northern Louisiana, Mississippi and Alabama. Hail up to egg size is possible, along with a tornado or two.
Senior meteorologist @matthewcappucci.bsky.social has a severe weather briefing.
We can't forget about the hail risk on Tuesday. Dual zones where hail could be large and damaging... both parts of the Corn Belt/Midwest and Texas:
