6/5/05 FCST: Great Lakes

[rdale]

TAMDAR soundings seem to show better wind profiles (both speed and direction) than the NAM is indicating, more in line with the RUC.

I'm looking for development after lunch over WI/IL and moving rapidly into MI by 2-3p. Tornado threat looks best over the northern half of the LP, down here I wouldn't be surprised if something dropped but more worried about squall line winds...

- Rob

 

[Jeremy Lemanski]

at 9am i'm watching what looks to be the outflow boundry from the overnight MCS moving east from lake michigan into lower michigan. So far, it shows little to no sign of slowing down and may pass over much of the area, but if it were to slow and stop somewhere in the central regions of the state this could provide a shot at tornados as storms later on interact with the boundry.

Also, some high and mid level clouds in and around the big rapids/cadillac area have limited heating a little, but its very early and these will likely do little to stop the climb in temps. As of 9am, some spots in SW mich. are already near 80 with points in the mid to upper 60s.

Finally, don't count of lake breezes today off Lake Huron. the water is bone chilling yet and if should they, the lake breezes form, it could also be the spot for tornados. Last year on june 13th i followed the supercell across huron county only to break the chase off 10 miles from the lake due to the storm, which appered to be losing its punch. Only later would i learn of the tornado it dropped only 7 miles away, thanks to lake breeze interaction.

 

[Alex Lamers]

I am surprised that SPC moved their moderate risk east of SE WI into Lake Michigan. I am expecting storms to develop and rapidly become capable of producing severe winds...mainly east of the Madison area. With LLJ 40-45 knots and ULJ focused right over the area...seems like it wouldn't be hard to transfer down some gusty winds.

I think best shot of tornadoes will be across E WI and NE IL where discrete modes will be present initially before linear mode takes over. BEST shot in that area would be over NE WI.

...Alex Lamers...

 

[Robert Dewey]

Originally posted by Alex Lamers
I am surprised that SPC moved their moderate risk east of SE WI into Lake Michigan. I am expecting storms to develop and rapidly become capable of producing severe winds...mainly east of the Madison area. With LLJ 40-45 knots and ULJ focused right over the area...seems like it wouldn't be hard to transfer down some gusty winds.

I think best shot of tornadoes will be across E WI and NE IL where discrete modes will be present initially before linear mode takes over. BEST shot in that area would be over NE WI.

...Alex Lamers...

I think they moved the risk eastward because of instability concerns over parts of WI. RUC only shows CAPE climbing up to 1500J/KG over that area (temps currently only around 70F), with little in the way of directional shear. Speed shear is pretty impressive, and it will likely lead to severe thunderstorms.

Further east into central/northern lower MI - Winds are more backed, and are forecast to stay that way. As the afternoon progresses, helicity across that region is forecast to be in the 200-300m2/s2 range, with good directional shear. Temps are also currently flirting with 80F, and are forecast to hit 90-95F (at least here in southern lower MI). No doubt that CAPE will press the 3000J/KG mark across much of MI and parts of IN. My thinking is that storms will initiate in lower MI, associated with the second outflow boundary (currently across IL). Storms in WI will probably fire as the 500mb vorticity center plows into the region. I think the tornado threat would tend to follow the area of the best backed winds, which would be northern lower MI - and IL, if things remain backed.

Today's setup really needs outflow boundaries and low level jet convergence to get things going in the weakly capped environment. Further northwest, into WI and the western U.P. of MI - there is little in the way of outflow boundaries, and the trough/front associated with the low is providing very little convergence. Still, the vort center swinging through should be enough to provide good development across that area.

I have seen many setups like today, where you have CAPE in excess of 3000J/KG, and it only takes a little bit of forcing and a little bit of shear. Today, we have a little bit of forcing and quite a bit of shear... Things should get pretty lit up later today...

 

[Robert Dewey]

Looking at the visible satellite loop, I can see an OB extending across northeast IL southwestward, blowing northeast pretty rapidly. There also appears to be some sort of mesoscale vorticity center in IL... SFC obs indicate temperatures down to the mid 70's underneath that wave. It will be interesting to see how things pan out this afternoon...

 

[Jeremy Lemanski]

MCD says tornado watch will be issued within the hour over lower michigan.

I also see the start of some Cumulus in the SW corner of the state based on the latest sat. With temps from the mid 80s to 90 across the area with points a couple of degrees either side of 70, things should really get going within the next few hours.


BTW, east winds in alpena and rogers city. If a sig. tornado were to occur today, that is where i would bet on for that to happen with the add local turning of the wind.

Also, look for the 18z soundings out of many offices around the area

 

[bill mudd]

phone reports from grand rapids wind storm causing festival chaos in town - sending people running for shelters - trees down and an eagle on radar with a lot more working up from IL and IN this afternoon

 

[Rebecca Robinson]

There is a tornado watch box up now for most of Michigan and NE part of Wisconsin.

 

[Rebecca Robinson]

Sorry for the double,
Radar is showing a good line of storms near Bay City and Port Huron.

Anyone chasing near there?

 

[bill mudd]

Bad axe (thumb tip) tornado warned......

 

[rdale]

This is the FORECAST thread...