7/3/2006 NOW: MI / WI / IN / IL

[nickgrillo]

Interesting looking day again. Latest sfc mesoanalysis shows a weak sfc circulation in eastern IA (with a nearly-stationary frontal boundary extending into northern IN). Latest RUC mesoanalysis shows the upstream boundary layer (south of the differential heating boundary -- associated with the slowly eroding cloud deck over northern IN) has destabilized quite well in response to sufficient insolation. For that matter, latest mesoanalysis shows CINH has eroded across much of the area, with two discrete deep convective cells south of Findlay OH (one of which is exhibiting strong low-level cyclonic rotation and tornado-warned). With +35-45kts of 0-6km shear across the region, I'd think additional supercell structures would be likely through the afternoon (and evening) with RUC-derived forecast soundings showing the region near I-80 destabilizing through the afternoon, with an increasingly veering boundary layer profile yielding elongated and cyclonically curved low-level hodographs. Additional elevated convection that has developed in IA (and IL) could root in the boundary layer as updraft inflow sources lower with time as CINH continues to erode in response to sfc diabatic heating. With 68-74F sfc tds, we'll be looking at low LCLs (e.g. <1200m AGL) through the whole day.

EDIT -- Well, the two discrete cells in westcentral OH aren't very discrete anymore.

 

[nickgrillo]

A broken, short convective band has initiated the past couple of hours of southwest/southcentral MI -- with an embedded cell gaining strong low-level rotation in the past couple of SRV scans (near Three Rivers in St. Jospeph Co). The 00z DTX (Detroit/Pontiac) observed sounding had ~1500j/kg of surface-based CAPE, with latest SPC mesoanalysis showing simuler values across much of southern MI (with negligable CINH for a surface-based parcel). I'm interested in getting some lightning shots tonight, so I may head west on I-94 and catch US-12 towards the Coldwater/Hillsdale area in a few... I'd expect convection to remain strong enough to produce large hail and a damaging sfc gust or two given the favorable buoyancy and 30-40kts of deep-layer shear for the next couple of hours (and hopefully the strong mechanical mixing can preclude a deepening inversion layer for the next several hours).

 

[HAltschule]

Anyone watching that wicked tornadic supercell in South-Central Michigan right now? As of 9:50pm EDT, there is some incredible G2G shear indicative of a serious tornadic threat, I was peeking around and it certainly jumped out at me. Tornado warning issued.

 

[mikegeukes]

The area has lots of farmland, with trees, nice couplet on radar.

0945 PM TORNADO 3 S THREE RIVERS 41.90N 85.63W
07/03/2006 ST. JOSEPH MI LAW ENFORCEMENT

2 SEPERATE FIRE DEPARTMENTS REPORTED A TORNADO BETWEEN
THREE RIVERS AND CONSTANTINE.

0955 PM TORNADO 3 SE CENTREVILLE 41.89N 85.49W
07/03/2006 ST. JOSEPH MI PUBLIC

REPORT OF A TORNADO OVER FISH LAKE...BETWEEN CENTERVILLE
AND STURGIS. RELAYED FROM COUNTY DISPATCH. [/b]

Mike

 

[Alexander Wall]

I figured with what I was seeing in GRLevel3, there was something on the ground there. I hope no one gets hurt, being nighttime. A lot harder to see...

 

[mikegeukes]

US 12 is a busy road, so is the Indiana Toll Road.

SEVERAL TORNADOES HAVE BEEN REPORTED ON THE GROUND IN SAINT JOSEPH
COUNTY MICHIGAN. THIS STORM IS CAPABLE OF PRODUCING STRONG TO
VIOLENT TORNADOES.[/b]

Mike

 

[HAltschule]

Interestingly, this supercell has had a TVS signature associated with it for more than 24 minutes now. If this thing has been putting down a tornado the whole time then some folks are in big trouble.

PS: SVR's state Law Enforcement has reported several tornadoes on the ground.

Undoubtedly this cell has a strong mesocyclone as it continues to pound out golfball to tennis ball sized hail.

THIS IS AN EXTREMELY DANGEROUS AND LIFE THREATENING SITUATION.
SEVERAL TORNADOES HAVE BEEN REPORTED ON THE GROUND IN SAINT JOSEPH
COUNTY MICHIGAN. THIS STORM IS CAPABLE OF PRODUCING STRONG TO
VIOLENT TORNADOES. [/b]

 

[Alexander Wall]

Looks like the cell is heading into Indiana now.

What is interesting is there is no watch - blue or red for the counties that the cells have passed through. It is headed for a blue box. I know just because there isn't a watch doesn't mean a tornado can't happen, but it seems rare.

 

[HAltschule]

Very true. But the SPC and local NWSFO's do say the watch is in effect "in and close to the watch area" for this very reason. But you're right...it's rare. Meanwhile, this monster cell had doppler indicated 3" hail (baseball sized) coinciding with the TVS. New convection is firing along the outflow of the TOR cell and I believe that this is going to disrupt the tornadic circulation significantly. Still a nasty storm though.