4/13 - 4/14 Severe Threat

[Chicago916]

Safe to say morning clouds/debris will not be an issue. Time to build instability and a strong cap. 

[Chicago Storm]

46 minutes ago, nvck said:

Also, thinking they may go MDT with the 1630z update

They should.

The ENH also needs to be greatly expanded as well, as that secondary zone of interest further south ( C IL) is gaining steam.

[HillsdaleMIWeather]

Morning rain is dying off fast, has a feeling it's gonna be one of those days 

[pen_artist]

Feeling more like a Chicago split right now but will see

 

[A-L-E-K]

24 minutes ago, pen_artist said:

Feeling more like a Chicago split right now but will see

 

We get bowing segment remnants from nw il and s wi sups

[pen_artist]

7 minutes ago, A-L-E-K said:

We get bowing segment remnants from nw il and s wi sups

Good point, guess I was more so referring to sups but yes models have been consistent in showing that. Definitely some touch and go to it.  15z HRRR wants to fire a mean storm over N Lasalle Co around 00z, so first hints of maybe some more initiation in NE IL.

[Chicago Storm]

14 minutes ago, A-L-E-K said:

We get bowing segment remnants from nw il and s wi sups

it's a sup day, even around here.

[sbnwx85]

Outflow boundaries from the morning MCS should make things fun, too.

[HillsdaleMIWeather]

SPC holds at enhanced due to uncertainty 

 

[ILSNOW]

2 minutes ago, HillsdaleMIWeather said:

SPC holds at enhanced due to uncertainty 

 

to add on

Any supercells than can remain on the warm/south side of the front
   will be capable of producing tornadoes, a few of which could be
   strong (EF-2/3). Some consideration was given to including greater
   tornado probabilities and a Moderate Risk (level 4 of 5) focused
   across southern WI/far northern IL. But, convection may have a
   tendency to grow upscale fairly quickly this evening, so confidence
   was not high enough for a categorical upgrade at this time.
   Regardless, very large to giant hail (potentially up to 3-4 inches
   in diameter) will be a threat with sustained supercells, and a swath
   of severe/damaging winds appears likely with a convective cluster
   spreading eastward across southern Lower MI this evening into
   tonight.

[snowlover2]

13 minutes ago, sbnwx85 said:

Outflow boundaries from the morning MCS should make things fun, too.

Expanded the slight south across much of IL/IN/OH because of this.

[King James]

These are the day you daydream about in January. Morning boomers, sunny afternoon with warm temps, and the promise of storms around dusk

[KeenerWx]

34 minutes ago, King James said:

These are the day you daydream about in January. Morning boomers, sunny afternoon with warm temps, and the promise of storms around dusk

Warm season with boomers & threat of severe cannot be beat. While the hotter action will be displaced north, still should get shot(s) at quality storms. 

[luckyweather]

DISCUSSION...The latest surface analysis depicts a quasi-stationary boundary extending from central/northern IA into southern/central WI, with an additional composite outflow boundary farther south from northeast IA into northern IL. Over the next few hours, continued diurnal heating of a moist air mass (upper 60s dewpoints) should erode remaining inhibition at the base a substantial EML, resulting in the development of strong surface-based buoyancy (upwards of 3000-3500 J/kg MLCAPE). As this occurs, initial thunderstorm development is expected across parts of central/eastern IA near the intersecting boundaries by around 19-22Z -- aided by a subtle frontal wave tracking eastward along the quasi-stationary boundary. The strongly unstable air mass coupled with 40-50 kt of effective shear will favor rapid thunderstorm organization/intensification into semi-discrete supercells and organized clusters. Initially, very large to giant hail (2-3+ inches in diameter) and severe wind gusts will be the main concern with potentially splitting supercells -- given a mostly straight hodograph. However, a south-southwesterly low-level jet will strengthen across the area later this afternoon into the evening and likely favor a transition to dominant right-moving supercells with a quickly increasing tornado risk. The strong buoyancy and 200-300+ m2/s2 effective SRH will support strong to intense tornadoes with any longer-lived supercells, along with a continued risk of giant hail and severe gusts. Eventually, thunderstorms may have a tendency of growing upscale into clusters with eastward extent, which will yield an increasing risk of damaging wind swaths.

[TheNiño]

Was wondering if that could possibly be the first PDS watch of the year. Might not be enough to reach that criteria but it could be close.

[ILSNOW]

 

Active meso's at the moment

[King James]

I couldn’t be in a better spot

[Chicago Storm]

initiation in IA.

spc gonna wait till they are tor-ing to issue a watch?

[TheNiño]

3 minutes ago, Chicago Storm said:

initiation in IA.

spc gonna wait till they are tor-ing to issue a watch?

It’s definitely time.

[sbnwx85]

Can never be too sure, I guess.

[sbnwx85]

Cell about to explode near Watseka 

[TheNiño]

Nice big watch box now. Some strong-ish language…

Tornado Watch for portions of Central and Eastern lowa Northern Illinois Extreme Southeast Minnesota

Southern Wisconsin Lake Michigan

• Effective this Tuesday afternoon and evening from 230 PM until 1000 PM CDT.
• Primary threats include...

Several tornadoes and a couple intense tornadoes likely

Widespread large hail and scattered very large hail events to 4

inches in diameter likely

Scattered damaging winds likely with isolated significant gusts to 75 mph possible

SUMMARY...Supercell thunderstorms will pose a threat for very large to giant hail this afternoon and evening as they track eastward, with the largest hailstones potentially reaching up to 3-4 inches in diameter. The threat for several tornadoes will increase later this afternoon and evening along a warm front, and any sustained supercell will be capable of producing a strong tornado. Otherwise, scattered to numerous severe/damaging winds may eventually occur as thunderstorms consolidate into one or more bowing clusters, with peak gusts up to 65-75 mph.

[MidwestChaser]

SPC should’ve just included NE IL in that watch; it’s just gonna be extended eventually.

[hawkeye_wx]

We are well inside the tornado watch, but models are mostly keeping the storms north of Cedar Rapids.

[frostfern]

That Iowa cell already looks like its producing massive hail.

[Chinook]

13 minutes ago, frostfern said:

That Iowa cell already looks like its producing massive hail.

It looks like it's about to rotate a bunch.

[Chicago916]

What does it take these days to get a Moderate risk? Doesn't make sense given the watch probabilities?

[mob1]

That's a pretty impressive hail core on this cell. 

[frostfern]

The biggest threat at the moment seems to be very large hail.  Low level shear needs to increase to get more tornadoes.  

[frostfern]

Independence cell is now tornado warned.