Chicago Storm Posted June 15, 2017 Share Posted June 15, 2017 I was going to extend the thread to the 17th, but I'm not the creator anymore.You're up Hoosier... Link to comment Share on other sites More sharing options...
snowlover2 Posted June 15, 2017 Author Share Posted June 15, 2017 46 minutes ago, Chicago Storm said: I was going to extend the thread to the 17th, but I'm not the creator anymore. You're up Hoosier... Took care of it since I noticed I had the first post. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted June 15, 2017 Share Posted June 15, 2017 Day 3 Slight Risk due to the uncertainty Link to comment Share on other sites More sharing options...
Hoosier Posted June 15, 2017 Share Posted June 15, 2017 Nice cluster of reports yesterday, especially WI Link to comment Share on other sites More sharing options...
janetjanet998 Posted June 15, 2017 Share Posted June 15, 2017 12z NAM bonkers for SAT GFS not so much but still decent Link to comment Share on other sites More sharing options...
snowlover2 Posted June 15, 2017 Author Share Posted June 15, 2017 Day 3 disco saying considerable upgrade possible. Quote It is possible that activity could consolidate and grow further upscale into one large forward (eastward/southeastward) propagating convective system capable of producing one or more broad swaths of potentially damaging wind gusts before convection weakens by late Saturday night. Correspondingly, severe probabilities may be increased considerably further in subsequent outlooks closer to the event. However, at this time, the forecast remains complicated by potential convective development in the preceding days, which remains unclear, and could provide negative feedback with regard to convective potential by Saturday. Coupled with some lingering differences among the models and within their ensemble output, uncertainties still seem to high for the outlook of more than 15 percent severe probabilities. Link to comment Share on other sites More sharing options...
Stebo Posted June 15, 2017 Share Posted June 15, 2017 7 minutes ago, snowlover2 said: Day 3 disco saying considerable upgrade possible. I would expect a considerable upgrade as well, most models are showing a pretty higher end potential for IA/IL/S WI and extending into N IN/S MI overnight. With a strong LLJ, strengthening low and ample instability, things will continue well into the night Saturday night. Link to comment Share on other sites More sharing options...
the ghost of leroy Posted June 15, 2017 Share Posted June 15, 2017 1 minute ago, Stebo said: I would expect a considerable upgrade as well, most models are showing a pretty higher end potential for IA/IL/S WI and extending into N IN/S MI overnight. With a strong LLJ, strengthening low and ample instability, things will continue well into the night Saturday night. you're already jinxing your derecho... Link to comment Share on other sites More sharing options...
Stebo Posted June 15, 2017 Share Posted June 15, 2017 2 minutes ago, cmasty1978 said: you're already jinxing your derecho... Actually I don't see a classic derecho setup, there is more directional shear with this than you'd expect with a derecho. It is a bit of semantics but I could see a group of supercells over Eastern IA eventually congealing into a strong QLCS with embedded tornadoes as the line races ENE. Link to comment Share on other sites More sharing options...
the ghost of leroy Posted June 15, 2017 Share Posted June 15, 2017 1 minute ago, Stebo said: Actually I don't see a classic derecho setup, there is more directional shear with this than you'd expect with a derecho. It is a bit of semantics but I could see a group of supercells over Eastern IA eventually congealing into a strong QLCS with embedded tornadoes as the line races ENE. even more jinxing Link to comment Share on other sites More sharing options...
Stebo Posted June 15, 2017 Share Posted June 15, 2017 Just now, cmasty1978 said: even more jinxing I don't believe in superstition, been working weather long enough to know if it is going to happen it will regardless of my wishes. Link to comment Share on other sites More sharing options...
hlcater Posted June 15, 2017 Share Posted June 15, 2017 This morning's NAM was interesting, I would expect, at the very least, a significant MCS, with perhaps a supercell window early on due to fairly decent low level curvature, especially on the 12z NAM. This is also evident on the GFS, but not as great of an extent. Also typical for June, instability and moisture are not issues. Link to comment Share on other sites More sharing options...
RCNYILWX Posted June 15, 2017 Share Posted June 15, 2017 Actually I don't see a classic derecho setup, there is more directional shear with this than you'd expect with a derecho. It is a bit of semantics but I could see a group of supercells over Eastern IA eventually congealing into a strong QLCS with embedded tornadoes as the line races ENE.Can't rule out rapid upscale growth with this setup but to me this seems similar to what we've since several times since 2010 with strong west to west northwest flow aloft. It seems that the default tendency is for SPC to favor MCS development but with the very favorable directional and speed shear and orientation to boundary, discrete/semi-discrete supercells appear probable for a while followed by possible eventual congealing/upscale growth. Am favoring the GFS and ECMWF for now given that the NAM12 appears convectively contaminated but what the globals show especially with GFS and ECMWF now in pretty good agreement, what they paint is a pretty ominous scenario for eastern IA, northern IL and southern WI late day Saturday through the evening. If the 12z 12km NAM scenario somehow becomes favored, then all bets are off. Link to comment Share on other sites More sharing options...
CheeselandSkies Posted June 15, 2017 Share Posted June 15, 2017 Saturday is the first day this year I'm actually getting legitimately pumped for a chase, of course it is still 2017 so trying to keep my expectations tempered. As alluded to by others, the greatest threat has been bouncing around WI, IA and IL from model to model and run to run, but has continued to look potent in any case and I have the weekend off so any target area should be within range, barring very drastic changes. Link to comment Share on other sites More sharing options...
hawkeye_wx Posted June 15, 2017 Share Posted June 15, 2017 Models this morning have trended a bit south with Saturday's event. The Euro has been most bullish for all of eastern Iowa, but the latest run has shifted to southern Iowa and points south and east. The CMC and UK are even farther south. Link to comment Share on other sites More sharing options...
Radtechwxman Posted June 15, 2017 Share Posted June 15, 2017 7 minutes ago, hawkeye_wx said: Models this morning have trended a bit south with Saturday's event. The Euro has been most bullish for all of eastern Iowa, but the latest run has shifted to southern Iowa and points south and east. The CMC and UK are even farther south. Possibly feedback from outflow from storms Fri night? If we had strong enough outflow it could def shunt the threat Sat pretty south Link to comment Share on other sites More sharing options...
hawkeye_wx Posted June 15, 2017 Share Posted June 15, 2017 44 minutes ago, StormChaser4Life said: Possibly feedback from outflow from storms Fri night? If we had strong enough outflow it could def shunt the threat Sat pretty south DMX's new discussion mentions that as one possibility, but says they are favoring a scenario in which Iowa destabilizes and storms fire farther north. Link to comment Share on other sites More sharing options...
Stebo Posted June 15, 2017 Share Posted June 15, 2017 45 minutes ago, StormChaser4Life said: Possibly feedback from outflow from storms Fri night? If we had strong enough outflow it could def shunt the threat Sat pretty south No, feedback from the MCS that forms during the day over Iowa, it modulates the wind fields and tries to force the low ESE which makes no sense with a predominately SW to W flow aloft. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted June 15, 2017 Share Posted June 15, 2017 18Z 3K NAM shows a quite large MCS Link to comment Share on other sites More sharing options...
hawkeye_wx Posted June 16, 2017 Share Posted June 16, 2017 A watch has been issued for eastern and southern Iowa. A cluster of storms has dropped golfball+ size hail in Cedar Falls/Waterloo. Link to comment Share on other sites More sharing options...
Hoosier Posted June 16, 2017 Share Posted June 16, 2017 Not much to add at this point. Saturday does look intriguing with shear vectors showing some crossover with the front. Should have a decent window for nasty discrete cells and then possibly an impressive QLCS. Link to comment Share on other sites More sharing options...
Radtechwxman Posted June 16, 2017 Share Posted June 16, 2017 26 minutes ago, Hoosier said: Not much to add at this point. Saturday does look intriguing with shear vectors showing some crossover with the front. Should have a decent window for nasty discrete cells and then possibly an impressive QLCS. I couldn't agree more. The cape/shear combo is pretty impressive for this time of year. Def could see a high end wind event, significant hail, and possibly tornadoes both prior to upscale growth and associated with mesovorticies associated with either a qlcs or bow echo Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted June 16, 2017 Share Posted June 16, 2017 2 hours ago, hawkeye_wx said: A watch has been issued for eastern and southern Iowa. A cluster of storms has dropped golfball+ size hail in Cedar Falls/Waterloo. I'm surprised DVN hasn't locally extended the watch to at least the Quad Cities: Cedar IA-Johnson IA-Jones IA-Clinton IA- 931 PM CDT THU JUN 15 2017 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 PM CDT FOR CEDAR...NORTHEASTERN JOHNSON...SOUTHERN JONES AND NORTHWESTERN CLINTON COUNTIES... At 931 PM CDT, severe thunderstorms were located along a line extending from Oxford Junction to 6 miles west of Lowden to 8 miles north of West Branch, moving southeast at 50 mph. HAZARD...60 mph wind gusts and quarter size hail. SOURCE...Radar indicated. IMPACT...Hail damage to vehicles is expected. Expect wind damage to roofs, siding, and trees. Locations impacted include... Anamosa, Tipton, Mechanicsville, Stanwood, Lowden, Wheatland, Olin, Delmar, Wyoming, Oxford Junction, Lost Nation, Bennett, Toronto, Morley, Rochester, Buchanan, Clarence, Cedar Valley, Bennett Park and Sutliff. This includes Interstate 80 in Iowa between mile markers 266 and 271. Link to comment Share on other sites More sharing options...
hawkeye_wx Posted June 16, 2017 Share Posted June 16, 2017 The severe storms passed just north and east of me. One little cell on the tail end moving through, but was pretty low-end. Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted June 16, 2017 Share Posted June 16, 2017 QCs now under a warning--again, still scratching my head why DVN didn't locally extend the watch to at least the QCs and the rest of their NW IL CWA: BULLETIN - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Warning National Weather Service Quad Cities IA/IL 944 PM CDT THU JUN 15 2017 The National Weather Service in the Quad Cities has issued a * Severe Thunderstorm Warning for... Rock Island County in northwestern Illinois... Southeastern Cedar County in east central Iowa... Scott County in east central Iowa... Northeastern Muscatine County in east central Iowa... * Until 1030 PM CDT * At 943 PM CDT, severe thunderstorms were located along a line extending from near Wheatland to near Bennett to near Rochester, moving southeast at 50 mph. HAZARD...60 mph wind gusts and quarter size hail. SOURCE...Radar indicated. IMPACT...Hail damage to vehicles is expected. Expect wind damage to roofs, siding, and trees. * Locations impacted include... Davenport, Moline, Rock Island, Bettendorf, East Moline, Durant, Silvis, Eldridge, Milan, Le Claire, Coal Valley, Wilton, Hampton, Walcott, Blue Grass, Buffalo, Andalusia, Long Grove, Lowden and Reynolds. This includes the following highways... Interstate 74 in Iowa between mile markers 1 and 5. Interstate 80 in Iowa between mile markers 265 and 303. Interstate 80 in Illinois between mile markers 2 and 5. Interstate 74 in Illinois between mile markers 1 and 7. Interstate 88 between mile markers 1 and 2. Interstate 280 between mile markers 1 and 18. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted June 16, 2017 Share Posted June 16, 2017 Yikes. Link to comment Share on other sites More sharing options...
hawkeye_wx Posted June 16, 2017 Share Posted June 16, 2017 The NAM now has our big stuff Friday night, then blows the cold pool well to the south and we never recover Saturday. Link to comment Share on other sites More sharing options...
AppsRunner Posted June 16, 2017 Share Posted June 16, 2017 20 minutes ago, hawkeye_wx said: The NAM now has our big stuff Friday night, then blows the cold pool well to the south and we never recover Saturday. Suspected this would be the case a few days ago. Tomorrow does look rather interesting though with a good chance for supercells during the late afternoon/evening before congealing into some type of MCS. Though instability won't be extreme, MLCAPE of 3000-3500 J/kg and some large curved hodos. The afternoon DMX afd mentioned a possible upgrade to moderate tomorrow, which I think is fairly likely at some point. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted June 16, 2017 Share Posted June 16, 2017 Day 2 Enhanced, SPC stresses however probs could be increased and expanded as evolution becomes clearer Link to comment Share on other sites More sharing options...
Hoosier Posted June 16, 2017 Share Posted June 16, 2017 Just now, homedis said: Where do you see this? kamala.cod.edu/spc Link to comment Share on other sites More sharing options...
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