A-L-E-K Posted July 21, 2011 Share Posted July 21, 2011 I decided to break this off from the main July thread because it has been so dry and LOT is mentioning some possible extreme totals and because there doesn't appear to be much of a wind/hail/tor threat associated, so no sense clogging that thread.' Early impressions from the July thread. Did some looking around and the 0z 4km WRF seems to have a decent handle on the on going action and blows up a really efficent slow moving w/e MCS from central Iowa into southern Wisconsin, slowly drifting south into extreme northern Illinois. Confidence is growing that there will be a stripe of 2"+ from northeast Iowa to MKE. Possible the target area shifts south some but probably not north. snippet from LOT SYNOPTICALY SPEAKINGSEVERAL INGREDIENTS APPEAR TO BE LINING UP TONIGHT FOR A LOCALIZED (BUT POTENTIALLY VERY SIGNIFICANT) HEAVY RAINFALL EVENT INCLUDING: 1) VEERING LOW LEVEL JET EVENTUALLY ALIGNING ITSELF WITH MID- UPPER LEVEL FLOW AS WELL AS THE FRONT 2) POOLING OF NEAR 80F DEW POINTS/PWATS 2.25"+ 3) LOW LCLS AND VERY HIGH FREEZING LEVELS SUPPORT VERY EFFICIENT RAINFALL RATES WHILE ALL OF THESE THINGS SCREAM POTENTIAL FOR LOCALIZED RAINFALL TOTALS IN EXCESS OF 5"+...THERE ARE STILL MANY HUGE "IF`S". FIRST...ALL OF THIS WILL HINGE ON ACTUAL MCS DEVELOPMENT TAKING PLACE AS THE MODELS SUGGEST. ASSUMING THIS OCCURS...QUESTION WILL THEN BE WHERE WILL THE THREAT BE GREATEST. BEST GUESS NOW IS THAT THREAT WILL BE GREATEST OVER NORTHWEST CWA...AND PROBABLY GREATER FARTHER NORTH AND WEST THAN THAT INTO SW WI OR EVEN IOWA. WITH SO MUCH UNCERTAINTY JUST PLAN TO HIGHLIGHT HEAVY RAIN POTENTIAL IN HWO AND MENTION HEAVY RAIN IN ZFP/GRIDS OVER NW CWA. Link to comment Share on other sites More sharing options...
wisconsinwx Posted July 21, 2011 Share Posted July 21, 2011 Well, convection seems to be starting in Iowa as expected. Curious why you think the target area cannot shift north. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 21, 2011 Author Share Posted July 21, 2011 Well, convection seems to be starting in Iowa as expected. Curious why you think the target area cannot shift north. Because model agreement on the front becoming quasi stationary over northern Illinois is pretty good, that places far northern Illinois into southern Wisconsin as the target zone. Current thinking is to favor southern Wisconsin between the border and 94. And obviously i'm talking about the area most likely for training/backbuilding convection areas north would still get wet. If convection is deep enough, thing could slide as far south as Chicago by Friday moring, but confidence is lower. This is all conditional on the MCS actually materializing of course. Link to comment Share on other sites More sharing options...
BowMeHunter Posted July 21, 2011 Share Posted July 21, 2011 Because model agreement on the front becoming quasi stationary over northern Illinois is pretty good, that places far northern Illinois into southern Wisconsin as the target zone. Current thinking is to favor southern Wisconsin between the border and 94. And obviously i'm talking about the area most likely for training/backbuilding convection areas north would still get wet. If convection is deep enough, thing could slide as far south as Chicago by Friday moring, but confidence is lower. This is all conditional on the MCS actually materializing of course. Last nights euro agrees pretty much.. has the heaviest amounts from rockford to LM with .5-1" Link to comment Share on other sites More sharing options...
wisconsinwx Posted July 21, 2011 Share Posted July 21, 2011 A strong, but not severe, thunderstorm in extreme SW Wisconsin. I wonder if this area of convection will try to make it into SE Wisconsin/NE Illinois this afternoon. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 21, 2011 Author Share Posted July 21, 2011 A strong, but not severe, thunderstorm in extreme SW Wisconsin. I wonder if this area of convection will try to make it into SE Wisconsin/NE Illinois this afternoon. Unlikely, as the dynamic environment is getting less and less favorable for that cell as it heads east, anything that fires in the area this afternoon / early evening will be widely scattered and likely south of I80. Your show will come late tonight into Friday morning with the possible MCS that fires this evening over Central or Eastern Iowa. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted July 21, 2011 Share Posted July 21, 2011 If you pretend the vis sat is radar it looks like an eastward moving bow echo with a nice waa wing lol I'm leaving for SC after I get off work and hoping to see some storms on the way that fire later this afternoon/evening. http://climate.cod.edu/flanis/1km.php?loop=1&type=vis®ion=N_Illinois&numimages=12 Link to comment Share on other sites More sharing options...
Chicago Storm Posted July 21, 2011 Share Posted July 21, 2011 FWIW...The HRRR shows any MCS activity that develops out west diminishes as it pushes northeast. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 21, 2011 Author Share Posted July 21, 2011 12z 4km wrf keeps any stationary front action south of I88. Link to comment Share on other sites More sharing options...
tornadotony Posted July 21, 2011 Share Posted July 21, 2011 My guess, given the current OFB position, is that any MCS/heavy rain threat tonight would focus along the I-80/US-30 corridor. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 21, 2011 Author Share Posted July 21, 2011 PWATs around .6 must feel good. Link to comment Share on other sites More sharing options...
wisconsinwx Posted July 21, 2011 Share Posted July 21, 2011 The NAM's the model that puts S Wisconsin in the crosshairs of the heavy rain event. Although it's been consistent, I'm very hesitant when the NAM's on its own. Link to comment Share on other sites More sharing options...
Indystorm Posted July 21, 2011 Share Posted July 21, 2011 Absolutely pouring here from pop up shower with filtered sunshine as well. Don't know if this is from a lake breeze shown on satellite and radar or some other convergence zone. Huge drops but small in areal coverage. IWX says it is a dying outflow boundary. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 21, 2011 Author Share Posted July 21, 2011 LOT has bumped pops to likely for tomorrow and added heavy rain wording, I know everyone's lawn could use a soaking. Link to comment Share on other sites More sharing options...
BowMeHunter Posted July 21, 2011 Share Posted July 21, 2011 The NAM's the model that puts S Wisconsin in the crosshairs of the heavy rain event. Although it's been consistent, I'm very hesitant when the NAM's on its own. lol NAM went from 2" at 12z to basically nothing at 18z.. Not sure what the new NAM shows I just looked at he regular old one. euro gives us .25"+ .50+" south and west. I'm not expecting jack but will hope for the best over the weekend. Link to comment Share on other sites More sharing options...
wisconsinwx Posted July 21, 2011 Share Posted July 21, 2011 lol NAM went from 2" at 12z to basically nothing at 18z.. Not sure what the new NAM shows I just looked at he regular old one. euro gives us .25"+ .50+" south and west. I'm not expecting jack but will hope for the best over the weekend. I think the emphasis has slightly shifted from a heavy rain threat to a potential severe threat. We all know how that story goes around here, though. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 21, 2011 Author Share Posted July 21, 2011 My guess, given the current OFB position, is that any MCS/heavy rain threat tonight would focus along the I-80/US-30 corridor. Lot afd still thinking i88 north, but splitting hairs given how fickle they can be. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 22, 2011 Author Share Posted July 22, 2011 Slow moving cells gathering strength over iowa / western illinois, moving ene, looks good for the i80/i88 corridore Link to comment Share on other sites More sharing options...
Baum Posted July 22, 2011 Share Posted July 22, 2011 Slow moving cells gathering strength over iowa / western illinois, moving ene, looks good for the i80/i88 corridore pulling back the carpet in the basement. Saw this same scenario about one year ago... atmosphere is juiced! http://www.nola.com/..._chicago_a.html guess some would love to see this again...not me...... inch or two too restore the deficit would be phenomenal. No severe. Just a good solid downpour. latest LOT disc... HOWEVER... GUIDANCE SUGGESTS REDEVELOPMENT OF ELEVATED CONVECTION ACROSS EASTERN IOWA BEYOND 06Z AND SHIFTS THAT EAST ACROSS NORTHERN IL TOWARD MORNING. BASED ON THESE TRENDS...HAVE INCREASED POPS THIS EVENING ALONG THE FRONT OVER WESTERN CWA...AND HAVE MAINTAINED THE HIGHER POPS ACROSS THE NORTHWEST IN THE 06Z-12Z TIME. seems to target the west and northwest zones. Not very clear or precise. IMO Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 22, 2011 Author Share Posted July 22, 2011 storms training where I originally suspected, eastern iowa to the wi/il border. Will push into chi if they hold together long enough EDIT: LOT has added heavy rain wording and bumped pops to likely, mini-drought relief in on the way. Link to comment Share on other sites More sharing options...
wisconsinwx Posted July 22, 2011 Share Posted July 22, 2011 I'm happy we'll at least get some rain, maybe a half inch to an inch in spots. Link to comment Share on other sites More sharing options...
Stevo6899 Posted July 22, 2011 Share Posted July 22, 2011 Nam showing some good rains here later today. Hope it doesn't scoot to the south. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 22, 2011 Author Share Posted July 22, 2011 Flood headlines for Lake and McHenry. Skies darkening pretty quick now with line approacing from the west. Should be all too siginificant, but 1/3-1/2 inch of rain is much needed. It may also help to hold up the boundary to the south and keep rain chances alive into the evening. Link to comment Share on other sites More sharing options...
Baum Posted July 22, 2011 Share Posted July 22, 2011 Loud cracks of thunder in Glen Ellyn and refreshing cooling rains....great thing Link to comment Share on other sites More sharing options...
BowMeHunter Posted July 22, 2011 Share Posted July 22, 2011 Nice to the south and pretty meh here like the euro was advertising.. enough to rinse the grass and about .25" tops I would guess... Hopefully the euro is real close again with the next round and we can get around .75" and more to the north. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 22, 2011 Author Share Posted July 22, 2011 nice looking elevated line pushing into the city, very dark skies. EDIT: looks like the potential for 1 or more MCS across the area this weekend, so i'll ammend this thread and keep it alive as a catch all for non-severe MCS related discussion. Wall of rain appears a couple miles west and closing in. Link to comment Share on other sites More sharing options...
wisconsinwx Posted July 22, 2011 Share Posted July 22, 2011 Nice to the south and pretty meh here like the euro was advertising.. enough to rinse the grass and about .25" tops I would guess... Hopefully the euro is real close again with the next round and we can get around .75" and more to the north. I would have to guess it's more like a half inch. Kenosha County has received 1 to 2 inches, with another inch or so on the way, so it's hard for me to think it was a quarter inch at best. Honestly, rain without big thunderstorms are much needed. There might be chances for bigger thunderstorms overnight tonight and perhaps Sunday. Link to comment Share on other sites More sharing options...
BowMeHunter Posted July 22, 2011 Share Posted July 22, 2011 I'm happy we'll at least get some rain, maybe a half inch to an inch in spots. Kenosha might end up around 1.50" give or take some. i doubt me or you even got .25" Euro was right on the money with LOT and this being an i-88 to kenosha special. Alek was all over this one nicely, too. Link to comment Share on other sites More sharing options...
BowMeHunter Posted July 22, 2011 Share Posted July 22, 2011 I would have to guess it's more like a half inch. Kenosha County has received 1 to 2 inches, with another inch or so on the way, so it's hard for me to think it was a quarter inch at best. Honestly, rain without big thunderstorms are much needed. There might be chances for bigger thunderstorms overnight tonight and perhaps Sunday. Maybe it was different by you but I doubt it.. 2 hrs of very light rain does not make .50" Very light rain keeps hanging on for dear life here the last 40 mins. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 22, 2011 Author Share Posted July 22, 2011 Maybe it was different by you but I doubt it.. 2 hrs of very light rain does not make .50" Radar is estimating under .30" up that way. Some seriously loud bangers with this line. Link to comment Share on other sites More sharing options...
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