Hoosier Posted July 12, 2017 Author Share Posted July 12, 2017 Here's LOT's take Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 858 PM CDT Tue Jul 11 2017 .UPDATE... 858 PM CDT Evening Update... Some adjustments to going forecast this evening primarily to tighten up gradient in pops with focus mainly across far north and northeast IL, and also bumped overnight mins, Wednesday maxes and dew point temps a bit. Surface analysis depicts warm front/old outflow boundary from central Iowa into central IL this evening. Wind fields are fairly light as would be expected this time of year however, with an overall lack of strong convergence along this boundary leading only to some isolated convection west of the Quad Cities late this afternoon. It appears the better focus for convection overnight will focus along the elevated baroclinic zone further north, where new convection has developed over the past 1-2 hours over northeastern IA. Convection allowing models (CAMs) are not doing real well with this activity overall, though the 23-00Z RAP runs seem to best capture the location of the northeastern IA storms, and have generally based overnight convective trends on its depiction, which develops storms northeast into southern WI and far northern IL, and eventually east-southeast across the lake. This would mainly affect northern tier of counties and the northern Chicago suburbs into the early morning hours, so have generally tightened up the pop gradient depicted in our hourly gridded forecast to go drier south/central portions of the cwa, with a tighter gradient to higher pops along the IL/WI border area. Steep mid-level lapse rates and 40-45 kt effective bulk shear would support well-organized updrafts which could present a hail threat from the strongest cores, though the greater concern will likely be the potential for locally heavy rainfall given the west/northwest to east/southeast orientation line of storms and potential for training within near 2" pwat atmosphere. Should be some northeastward drift of the elevated warm front overnight so threat may be more of a southern WI issue. Ratzer Link to comment Share on other sites More sharing options...
Jim Martin Posted July 12, 2017 Share Posted July 12, 2017 Tornado Warning near Prairie du Chien, Wisconsin currently. Link to comment Share on other sites More sharing options...
Powerball Posted July 12, 2017 Share Posted July 12, 2017 Getting decent lightning right now from the cluster of storms just NW of here, even some CTG strikes. Link to comment Share on other sites More sharing options...
CheeselandSkies Posted July 12, 2017 Share Posted July 12, 2017 That MS River cell raising MKX's eyebrows. SPC still hasn't said anything about that group of storms (MD for watch probability wouldn't be amiss...). Edit (just came out). National Weather Service Milwaukee/Sullivan WI 800 PM CDT Tue Jul 11 2017 .UPDATE... The atmosphere is not cooperating. The high resolution guidance, including the NAM, had been suggesting that we`d see rapid redevelopment toward midnight along a NW/SE line from about Baraboo to Milwaukee. This would be along or near the 850mb warm front lifting through. However, satellite imagery shows an upper level jet streak has helped to trigger early convection along that 850 boundary over far northeast IA. So, this new convection is likely to just expand and roll across the area through the evening hours. We have the moisture, with dewpoints well into the 70s, effective deep layer shear is pushing 40-50kts. MUCAPE is around 2500J/KG. This is a rapidly changing evolution, remain flexible in your expectations. Severe storms with large hail and strong winds are the primary threat, but a few tornadoes are possible, especially during the evening, west of Madison. Link to comment Share on other sites More sharing options...
Jim Martin Posted July 12, 2017 Share Posted July 12, 2017 Link to comment Share on other sites More sharing options...
CheeselandSkies Posted July 12, 2017 Share Posted July 12, 2017 Came out as I was typing. Link to comment Share on other sites More sharing options...
hlcater Posted July 12, 2017 Share Posted July 12, 2017 Adding to the late to the party crowd, I was in North Liberty for most of the day, watched that supercell develop, but after seeing it struggle to the west, and not checking mesoanalysis, I left it(IDIOT!). Only to end up turning around after it dropped the tornado, ended up missing that, but got some fantastic structure as a consolation prize. Still kinda burns missing a tornado I could've easily had if I had only been more observant and checked obs. Link to comment Share on other sites More sharing options...
Powerball Posted July 12, 2017 Share Posted July 12, 2017 00z NAM does something completely funky. But the long and short of is it's showing one big nothingburger for majority of the slight risk area tomorrow afternoon and evening, and in fact makes Thursday the "big day." Link to comment Share on other sites More sharing options...
Powerball Posted July 12, 2017 Share Posted July 12, 2017 Honestly, I'm surprised DTX hasn't issued a flood advisory for the northern suburbs. Between the storms that hit those areas earlier today and how slow tonight's storms are moving, I'm quite sure there's some urban flooding at this point. Link to comment Share on other sites More sharing options...
Stebo Posted July 12, 2017 Share Posted July 12, 2017 4 minutes ago, Powerball said: 00z NAM does something completely funky. But the long and short of is it's showing one big nothingburger for majority of the slight risk area tomorrow afternoon and evening, and in fact makes Thursday the "big day." Yeah I don't see the 12km NAM being right on this, too far north with the boundary and terribly handling the convection to our west. Link to comment Share on other sites More sharing options...
Stebo Posted July 12, 2017 Share Posted July 12, 2017 Very impressed with the amount of lightning I am seeing even from here. Lots of CG/CC strikes. Link to comment Share on other sites More sharing options...
Powerball Posted July 12, 2017 Share Posted July 12, 2017 1 minute ago, Stebo said: Very impressed with the amount of lightning I am seeing even from here. Lots of CG/CC strikes. I've also been getting decent rumbles of thunder for the past 45 minutes, even with the storms being a good 10+ miles away. Link to comment Share on other sites More sharing options...
Stebo Posted July 12, 2017 Share Posted July 12, 2017 Just now, Powerball said: I've also been getting decent rumbles of thunder for the past 45 minutes, even with the storms being a good 10+ miles away. My sent me a small video on FB of some impressive CC (spider lightning) just a bit ago from Eastpointe. Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted July 12, 2017 Share Posted July 12, 2017 14 minutes ago, Stebo said: Very impressed with the amount of lightning I am seeing even from here. Lots of CG/CC strikes. Same over on our side of the lake. Prolific lightning giving that strobe like sky Link to comment Share on other sites More sharing options...
Stebo Posted July 12, 2017 Share Posted July 12, 2017 Just now, SchaumburgStormer said: Same over on our side of the lake. Prolific lightning giving that strobe like sky I just hope to see some of that tomorrow night in my area. Love a good night storm. Link to comment Share on other sites More sharing options...
Powerball Posted July 12, 2017 Share Posted July 12, 2017 11 minutes ago, Stebo said: I just hope to see some of that tomorrow night in my area. Love a good night storm. Agreed. What we're getting now pales in comparison to what's happening in Illinois (300+ strikes per minute). Link to comment Share on other sites More sharing options...
Stebo Posted July 12, 2017 Share Posted July 12, 2017 Just now, Powerball said: Agreed. What we're getting now pales in comparison to what's happening in Illinois (300+ strikes per minute). Yeah 300+ a minute is real deal stuff. Link to comment Share on other sites More sharing options...
homedis Posted July 12, 2017 Share Posted July 12, 2017 Flash flood warning here, severe storm approaching from the west, some roation just west of Elgin as well. Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted July 12, 2017 Share Posted July 12, 2017 10 minutes ago, homedis said: Flash flood warning here, severe storm approaching from the west, some roation just west of Elgin as well. Really broad and weak at the moment Link to comment Share on other sites More sharing options...
homedis Posted July 12, 2017 Share Posted July 12, 2017 Really broad and weak at the momentYeah definitely but keeping a super close eye to it Link to comment Share on other sites More sharing options...
Chicago Storm Posted July 12, 2017 Share Posted July 12, 2017 Nice supercell not too far from home. Figures I'm nearly 2 hours west camping.Quarter size hail and 78mph wind gust reported with it. Had had a few weak couplets a short time ago as well. Link to comment Share on other sites More sharing options...
Central Illinois Posted July 12, 2017 Share Posted July 12, 2017 2.75" fell here this morning it was quite the storm it had a warning on it when it came throughSent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
snowlover2 Posted July 12, 2017 Share Posted July 12, 2017 Quite the unexpected wind event here yesterday. Lots of trees down and power outages all around Dayton. Link to comment Share on other sites More sharing options...
hlcater Posted July 12, 2017 Share Posted July 12, 2017 (10 min ago) Reports of powerflashes under a large lowering in Chicago, may not be a tornado, but at the least strong winds if true. Radar presentation is not really impressive, but neither was the storm in Iowa earlier, and look what we got. Link to comment Share on other sites More sharing options...
Hoosier Posted July 12, 2017 Author Share Posted July 12, 2017 1 hour ago, homedis said: Flash flood warning here, severe storm approaching from the west, some roation just west of Elgin as well. That cell still has a decent look to it on reflectivity. Link to comment Share on other sites More sharing options...
RobertSul Posted July 12, 2017 Share Posted July 12, 2017 Wow, the Cassville, WI area is experiencing some intense rainfall. Radar estimates of 8+ inches and heavy rain is still training through the area. Link to comment Share on other sites More sharing options...
snowlover2 Posted July 12, 2017 Share Posted July 12, 2017 Most of IN/OH now in a slight risk on new day 2. Link to comment Share on other sites More sharing options...
tuanis Posted July 12, 2017 Share Posted July 12, 2017 7 inches and counting. Yard is a running river. House flooded. Hate these setups. Link to comment Share on other sites More sharing options...
kevlon62 Posted July 12, 2017 Share Posted July 12, 2017 Walworth County getting pummeled this morning as well. Field, ditch and wetland flooding was prolific. There were channels through the corn fields where stalks were battered to the ground from the rushing water like you see after a high wind event. That was something new for me. Link to comment Share on other sites More sharing options...
hawkeye_wx Posted July 12, 2017 Share Posted July 12, 2017 8+ inches of rain fell nw of Dubuque last night. I haven't seen a drop since the initial Sunday night MCS. Link to comment Share on other sites More sharing options...
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