7/19/06 NOW: MN / IA / WI / IL

Well, they cancelled the watch that what only in effect until 8 PM. There will still likely be strong thunderstorms in the northern half of Illinois later tonite, granted that the cap breaks in Iowa and storms do indeed form.
 
Hey Y'all. What an pre-storm environement in IA!!!. Sort of reminds me of the Jarrell, TX but much more unstable CAPE-wise.

Anyway, with the main storms in IL at least for right now, here is a link to the streaming webcam in Jacksonville, IL which is ahead of the line of storms. http://webcam.ic.edu/view/view.shtml
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hey thanks i was wondering how nasty these storms would look.....is this facing west??? do you know?
 
I've been watching the thin cumulus field in far northwest Iowa and so far it's been pretty quiet. A few elevated looking showers are still along the western end of that line in northeast NE. As of right now, it still looks pretty capped. But we all know with this amount of instability that can change very fast.

Very well defined outflow/differential heating boundary from the southeast tip of IA to just northeast of DMX into northwest IA. Nothing appears to be popping along this boundary as of yet either, but there are some statocumulus looking clouds.
 
The webcam I posted is definitely rocking right now. Did you see the small tree limbs/branches blow across the screen as the gust front pushed through. Winds must have been 45-50mph as those trees were bent over. Also some neat lightning flashes.

New doppler SRV1 scan shows strong gate 2 gate shear south of Springfield. Me thinks a tornado might be on the ground or imminent there!!
 
Hey Y'all. What an pre-storm environement in IA!!!. Sort of reminds me of the Jarrell, TX but much more unstable CAPE-wise.

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I liken it more to the 6/20/06 bust in IA... That day featured strong instability, pretty good low-level shear along and to the north of the OFB, which was located in a similar area as the current OFB. In addition, if I remember correctly, the strongest sfc convergence was in far nw IA, similar to where it is now. Of course, 6-20-06 was a non-event owing to some capping and subsidence in the wake of morning convection and an early-afternoon shortwave trough. Wait a second, that sounds familiar...

Orange City IA (NW IA) is 95/81... Yuck. Looking at sfc winds in that area, there must be pretty substantial surface convergence... Orange City has ENE winds, while Le Mars IA (less than 15 miles to the south-southwest of Orange City) has SSW winds. Other obs nearby seem to support this wind field.

Edit: The storms in ne NE may actually help storms develop in nw IA soon... Low-level RH is relatively low in Nebraska, which means that there is likely some decent evaporational cooling occurring in the low-levels. With WSW 850-700mb flow, this cooled air may advect into nw IA, replacing the warmer temps that have capped off nw IA to surface-based parcels thus far. The same may happen if elevated showers continue to develop in nw IA -- evaporational cooling of the capping layer. I'd imagine this effect would be most prominent when there is significant directional shear in the low-levels, in which case the 850-700mb rain-cooled air would advect differently than the sfc outflow (which means that you can have rain-cooled 850-700mb "air" atop the warm, moist air at the surface) . This is the case (to a degree) today in IA.

Surface-based instability decreases quite a bit east of Estherville, where temperatures are being held in the upper-70s to mid-80s (relative to the mid-90s to near 100F farther west). Eek, Storm Lake is 97/77? Miserable.
 
storms developing in northern illinois and southern wisconsin looks mostly elevated but idc i need a storm its a sickness i think.......maybe the cap is breaking some
 
I know what you're talking about Jeff. There's still quite a bit of CIN over the area despite LI's now at -14!! Of interest is the Supercell Composite number at 52 and the Craven Significant Severe value of 190!! These values are off the charts. We all see the boundaries colliding with each other over the DSM area and I would think that that would be the best shot for initiation in the near term if anything happens at all. Otherwise, we'll have to wait a few more hours for the Low itself to pass through. Bottom line...nothing happening yet, but if it does, I agree we'll see extremely rapid Severe Development warranting, IMO, a PDS Tornado box without a doubt!!
 
New development (albeit elevated above the cap) now increasing in coverage and intensity NW of Rockford and Freeport, IL. Storms will likely track into northern sections of the Chicago metro later this evening. It looks like just a heavy rain and maybe a hail threat for now.
 
Sitting at home looking at clear skies :( I am wondering if anyone knows if the cap is weakening or not across Iowa? Also is that a boundary in central Iowa on the radar?
 
Nice little bow echo headed my way :rolleyes:

Anyhoo...nice work by STL NWS.

Blanket svr warnings for 11 counties WELL ahead of the line.

"WIND DAMAGE WITH THIS STORM WILL OCCUR WELL AHEAD OF ANY RAIN OR
LIGHTNING."

Ought to get some folks attention.
 
Yes. That is a massive outflow boundary from earlier convection. It running into moisture convergence coming up from the south. All of it is meeting along that line in Central Iowa. The problem is, the atmosphere is still too capped to get any storms going. It is weakening (has weakened) but not enough to break/erode the cap as of yet. Once it does erode (or IF it does), you'll probably know it within 15-20 minutes as severe thunderstorms across parts of IA should erupt explosively.
 
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