May 19-22 Severe Weather Threat

[A-L-E-K]

Not buying it...would likely have to mix above 850 mb for that to happen. That model has been known to have problems handling surface temps and I would guess the same is true for dewpoints. Could see things hanging in the 50s though.

 

 

yeah it's suspiciously low and as mentioned above the HRRR recovers nicely.

[Gilbertfly]

that little cluster in the quincy area has a nice moisture feed behind it...with nice clearing behind it as well....that could help to moisten things up around here for later on this evening...

[A-L-E-K]

old but LOT (izzi) not overly confident one way or the other

 

FAIRLY LOW CONFIDENCE FORECAST IN TERMS OF CONVECTIVE THREAT AND
EVOLUTION IN OUR CWA TODAY...DUE LARGELY TO THE FAIRLY NEBULOUS
FORCING.

WATER VAPOR IMAGERY SHOWS ONE LEAD SHORTWAVE SHEARING OUT OVER
EASTERN IL AND EASTERN WI LATE THIS MORNING WITH SUBSIDENCE EVIDENT
ACROSS THE AREA IN ITS WAKE LIKELY TO RESULT IN A GOOD DEAL OF
SUNSHINE AND OPPORTUNITY TO DESTABILIZE THIS AFTERNOON. A MUCH
STRONGER AND MORE PRONOUNCED VORT MAX IS OVER SOUTHERN MN ARCING
SOUTH INTO IOWA AND NORTHERN MISSOURI. WATER VAPOR IMAGERY SHOWS
THIS VORT PIVOTING NORTHWARD AND UNLIKELY TO HAVE MUCH OF AN
IMPACT ON OUR AREA THIS AFTERNOON.

REALLY...AT THIS POINT THE MOST OBVIOUS CLUE AS TO OUR CONVECTIVE
POTENTIAL THIS AFTERNOON APPEARS TO BE WITH A SMALL CLUSTER OF
ELEVATED THUNDERSTORMS OVER CENTRAL MISSOURI THAT HAVE FORMED AT THE
TAIL OF THE MN/IA VORT AND ALONG THE NORTHERN PERIPHERY OF A PLUME
OF VERY STEEP MID LEVEL LAPSE RATES SAMPLED BY SGF/OUN/LIT SOUNDINGS
THIS MORNING. THIS SMALL CLUSTER OF STORMS HAS MANAGED TO HANG ON
ALL MORNING AND GROWING CONCERNED THAT WITH STRONG HEATING TAKING
PLACE AHEAD OF THE STORMS THAT THEY COULD BECOME ROOTED IN THE
BOUNDARY LAYER AND POTENTIALLY GROW UPSCALE/INTENSIFY THIS AFTERNOON
WHILE MOVING NORTHEAST INTO OUR CWA.

MODERATELY STRONG SOUTHWESTERLY MID LEVEL FLOW IS PROGGED TO ADVECT
THE STEEPER MID LEVEL LAPSE RATES NORTHEAST INTO THE CWA LATER TODAY
AIDING THE DESTABILIZATION PROCESS. FAIRLY STRONG DEEP LAYER SHEAR
AND MODERATE INSTABILITY LOOK SUFFICIENT FOR ORGANIZED/SEVERE TSTMS
LATER THIS AFTERNOON INTO THIS EVENING. IF THE SMALL CLUSTER OF
STORMS OVER MISSOURI BECOMES OUR MAIN SHOW THEN STORM MODE WOULD
LIKELY BE MORE LINEAR WITH PRIMARY THREAT BEING DAMAGING WINDS AND
HAIL...THOUGH SHOULD MORE DISCRETE CELLS FORM SHEAR/INSTABILITY ARE
SUCH THAT A TORNADO CANNOT BE RULED OUT.
 

[IWXwx]

Deep layer shear will be sufficient to get some supes but we'll probably have mixed mode. Great point about the already thinning cloud debris. If anything, the presence of scattered leftover debris can serve as differential heating boundaries that provide a focus for convection.

Sent from my SCH-I535 2

 

Just catching up and read this. This is something that many people overlook when searching for a trigger.

 

Even though NE IN is under a slight risk, I feel that we're in no man's land up here. Storms will be decaying by the time they get here tonight.

[Hoosier]

Although CAPE values and tornado threat will be hurt in areas with lower dewpoints, the T/Td spreads (now pushing 30 degrees in N IL) and rather thick layer of dry adiabatic low level lapse rates could still mean that a pretty decent damaging wind threat evolves later.

[OntarioChaser]

I'm really liking S ON for a continued severe threat through the late evening hours.  Chase likely.

[London snowsquall]

I'm really liking S ON for a continued severe threat through the late evening hours.  Chase likely.

 

Feeling pretty muggy out there.  Temperature up to 80 with a 68 DP and continued clear skies.  Anything that gets going could make for some interesting weather later on.

[weathergy]

FWIW, HRRR shows 70+ dps surging north by 4PM....

Honestly, I feel that the SPC should have issued the watch for just northern MI, and maybe the thumb. The lack of shear in these parts concerns me, and leads me to believe the threat will stay north of I-69.

 

Unless things change quickly, I don't believe I'm going to see anything IMBY.

[A-L-E-K]

Although CAPE values and tornado threat will be hurt in areas with lower dewpoints, the T/Td spreads (now pushing 30 degrees in N IL) and rather thick layer of dry adiabatic low level lapse rates could still mean that a pretty decent damaging wind threat evolves later.

 

 

yeah, RAP is showing some nice dcape and low level lapse rates over our area later this evening.

[Powerball]

The airmass over Detroit is an absolute powde keg. Actually, I'm a bit surprised by how unstable/moist it is.

[Chinook]

Is that a supercell offshore from Charlevoix MI, or am I going crazy?

[weathergy]

The airmass over Detroit is an absolute powde keg. Actually, I'm a bit surprised by how unstable/moist it is.

Unfortunately, it looks like it might all go to waste.

[A-L-E-K]

Unfortunately, it looks like it might all go to waste.

 

 

southern edge of the line is showing signs of life but you're clearly riding the edge.

[A-L-E-K]

89/54 at MDW...making a run at the upper 40s?

[huronicane]

Looking at the DVN 18z sounding...yikes. Looks pretty awful for storms.

(null)

[A-L-E-K]

Looking at the DVN 18z sounding...yikes. Looks pretty awful for storms.

(null)

[chase_stormz]

Looking at the DVN 18z sounding...yikes. Looks pretty awful for storms.

(null)

 

Yea, I agree. Looking pretty bad for anyone who wants some storms to chase. However, it still appears a quick recovery may occur this afternoon and just delay storm initiation until this evening. Areas from Keokuk, IA down toward areas north of St. Louis back into MO. Might still head w/sw and give it a go later this afternoon.

[weatherbo]

Golf ball size hail here in Antrim county

[Gilbertfly]

89/54 at MDW...making a run at the upper 40s?

89/47 in the brook

[A-L-E-K]

89/47 in the brook

 

 

lol, you have to wonder if the late start to the growing season and recent dry conditions are shaving off a few points here

[Hoosier]

Here's the 18z DVN sounding. Unfortunately ILX didn't do one.

[Gilbertfly]

lol, you have to wonder if the late start to the growing season and recent dry conditions are shaving off a few points here

it can't be helping matters....

 

now 90/49 here....guess it's on the rise?  winds kicking pretty good

[Harry Perry]

Dew point down 64 from 68 earlier. Looks like most of the action will be north of I-96.

Southward development is not happening anymore with the cluster of storms near GRR. Looks like we may stay high and dry, but ATLEAST if something pushes some sort of outflow boundary into any area this evening, a storm or two could evolve, leading to upscale growth due to higher than expect parameters due to the lack of earlier convection/clouds.

I think GRR handled it well with isolated storms this evening, ending by midnight. The severe thunderstorm watch may be canceled down here early, but if ANY sort of a boundary is moving in our direction, which there is, they may hold onto it until 8.

I bet the line fills in East of Jackson and blasts Detroit this evening.

[Castaway]

89/47 in the brook

90°/53 here in dupage. The wind is relentless

[Natester]

Downed tree branch across the street.  The winds were particularly nasty here.

[Castaway]

that little cluster in the quincy area has a nice moisture feed behind it...with nice clearing behind it as well....that could help to moisten things up around here for later on this evening...

That should roll through by 5pm

[Hoosier]

Some small cells have fired up east of here.

This thread seemed like it was missing something, and then I remembered, some of our severe posters are out chasing in the Plains.

[Hoosier]

88/52 at ORD and unofficial sites have dipped into the upper 40s. Impressive stuff and a model butchering sans RAP.

[Geos]

86/56 here now. Noticing some debris clouds drifting by. Winds have been quite gusty this afternoon.

 

- RAC ahead at 89°/55°

[A-L-E-K]

88/52 at ORD and unofficial sites have dipped into the upper 40s. Impressive stuff and a model butchering sans RAP.

 

 

90/50 at MDW...brutal stuff