pen_artist Posted February 27 Author Share Posted February 27 Most recent HRRR run (20z) returning to showing some discrete cells in Chicagoland between 6PM-11PM. 1 Link to comment Share on other sites More sharing options...
andyhb Posted February 27 Share Posted February 27 Good moisture depth and quality in this 19z observed sounding from UIUC (Champaign). Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted February 27 Share Posted February 27 Watch is out for N IL, 60/40 tornado probs 1 Link to comment Share on other sites More sharing options...
Possum Posted February 27 Share Posted February 27 Don't think I've ever seen baseball sized hail mentioned for NE IL.I sure haven’t in my 9 years living here. And in February?? Wild times…. Link to comment Share on other sites More sharing options...
IWXwx Posted February 27 Share Posted February 27 From the wording of the watch (a couple of intense tornadoes and 3" hail likely), I'm kind of surprised that they didn't go PDS. EDIT: Especially since an extremely large population center is bullseye. 1 Link to comment Share on other sites More sharing options...
Indystorm Posted February 27 Share Posted February 27 17 point dew point spread between Davenport IA and Princeton IL 41 to 58 1 Link to comment Share on other sites More sharing options...
Indystorm Posted February 27 Share Posted February 27 1 minute ago, IWXwx said: From the wording of the watch (a couple of intense tornadoes and 3" hail likely), I kind of surprised that they didn't go PDS. Probably because moisture is not all that high in the sixties but the contras is great for this time of year 1 Link to comment Share on other sites More sharing options...
frostfern Posted February 27 Share Posted February 27 1 minute ago, Indystorm said: 17 point dew point spread between Davenport IA and Princeton IL 41 to 58 I noticed that too. Significant dryline with actual warmth behind it in February is wild. Link to comment Share on other sites More sharing options...
Indystorm Posted February 27 Share Posted February 27 Satellite looking interesting sw and se of the Quad cities. Expect formation soon if cap allows Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted February 27 Share Posted February 27 Initiation going in NE Illinois Link to comment Share on other sites More sharing options...
Castaway Posted February 27 Share Posted February 27 8 minutes ago, IWXwx said: From the wording of the watch (a couple of intense tornadoes and 3" hail likely), I'm kind of surprised that they didn't go PDS. EDIT: Especially since an extremely large population center is bullseye. The initial wording in the Tornado watch on the iOS weather app caught my eye Severity: Extreme Extraordinary threat to life or property Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted February 27 Share Posted February 27 That supercell that went up in the Quad Cities CWA has to be one of the fastest formations to SVR Warnings I've ever seen, around 10 mins 1 Link to comment Share on other sites More sharing options...
frostfern Posted February 27 Share Posted February 27 3 minutes ago, Indystorm said: Probably because moisture is not all that high in the sixties but the contras is great for this time of year I remember March 31 didn't have super high dewpoints. Only low 60s at best. Low LCLs AND good instability still happened because it was cold aloft. Same here. The warm sector was a little broader and deep layer shear was stronger though. That seems like the only thing off. The best shear arrives after dark. 1 Link to comment Share on other sites More sharing options...
Chinook Posted February 27 Share Posted February 27 1 minute ago, HillsdaleMIWeather said: That supercell that went up in the Quad Cities CWA has to be one of the fastest formations to SVR Warnings I've ever seen, around 10 mins Cyclone77 storm 1 Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted February 27 Share Posted February 27 Absolutely explosive growth on that cell in NW IL 1 Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted February 27 Share Posted February 27 1 minute ago, SchaumburgStormer said: Absolutely explosive growth on that cell in NW IL Been a storm for 10 minutes and already mping reports of 1” hail 2 Link to comment Share on other sites More sharing options...
Possum Posted February 27 Share Posted February 27 Absolutely explosive growth on that cell in NW IL Can’t believe how fast it went severe warned. Already seeing a hook trying to form too.. 1 Link to comment Share on other sites More sharing options...
Stx_Thunder Posted February 27 Share Posted February 27 5 hours ago, frostfern said: Elevated and high based don’t mean the same thing. You can have either one and not the other. Out west you often have high based storms that are still rooted in the boundary layer, because the boundary layer is extremely deep. Storms that move over Lake Michigan are almost always elevated, technically, in the spring and summer because surfaces based parcels are rarely unstable, but the cloud base is often way lower than what you’d see in Colorado, New Mexico, or Arizona. Just to reference for everyone on here in case some aren’t as informed, NWS defines ‘Elevated Convection’ on their meteorological discussion glossary as this: https://forecast.weather.gov/glossary.php - - - And I never wrote that ‘elevated’ and ‘high-based’ storms were indeed the same and I already explained what high-based normally, or better yet, logically means. ’High-based’ though, can be interpreted differently because it is not an existing term in the NWS glossary. But, SPC also uses both terms in their convective discussions (and it’s been like that for a lot of years now as I’ve seen & read). Each forecaster may very well have a different interpretation of what's actually ‘High-based’ to them. But they could also just be meaning ‘Elevated’ at the same time too because there doesn’t seem to be an actual top layer criteria that strictly defines an elevated storm, looking at that NWS definition. ’Surface-based’ is indeed in their glossary as well. But it obviously has no room for individual interpretation because it inevitably means storms that are based within the surface layer (very near the ground), as written on there. Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted February 27 Share Posted February 27 Unzipping to the SW of the initial storm. Off to the races 1 Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted February 27 Share Posted February 27 Gnarly looking hail core near @cyclone77 Link to comment Share on other sites More sharing options...
Indystorm Posted February 27 Share Posted February 27 Low level helicity is stronger down by the Ohio river than up in northern IL, but we shall see what happens. Link to comment Share on other sites More sharing options...
Chinook Posted February 27 Share Posted February 27 Grlevel3 already has hail information on the two new ones 1 Link to comment Share on other sites More sharing options...
frostfern Posted February 27 Share Posted February 27 16 minutes ago, Stx_Thunder said: Just to reference for everyone on here, NWS defines ‘Elevated Convection’ on their meteorological discussion glossary as this: https://forecast.weather.gov/glossary.php - - - And I never wrote that ‘elevated’ and ‘high-based’ storms were indeed the same and I already explained what high-based normally, or better yet, logically means. ’High-based’ though, can be interpreted differently because it is not an existing term in the NWS glossary. But, SPC also uses both terms in their convective discussions (and it’s been like that for a lot of years now as I’ve seen & read). Each forecaster may very well have a different interpretation of what's actually ‘High-based’ to them. But they could also just be meaning ‘Elevated’ at the same time too because there doesn’t seem to be an actual top layer criteria that strictly defines an elevated storm, looking at that NWS definition. ’Surface-based’ is indeed in their glossary as well. But it obviously has no room for individual interpretation because it inevitably means storms that are based within the surface layer (very near the ground), as written on there. Okay. At this time of year in the eastern regions of the US high based storms are usually also elevated and non-severe. So yea, in this context what you said makes sense. It just seemed like an overgeneralization to say "high base" means non-severe, so I responded. No need to nitpick anymore. We both get it. Link to comment Share on other sites More sharing options...
Stx_Thunder Posted February 27 Share Posted February 27 1 hour ago, Chinook said: Grlevel3 already has hail information on the two new ones Not surprised as I just checked the SPC 22Z DVN (Davenport IA) observed sounding. Again similar to a few weeks ago in eastern TX, Low CAPE (282 MU), but both steep low & mid-level lapse rates. Surface temp at 72 F which I guess pretty warm for this time of year up there. WBZ height isn’t ideal for large hail, but FZL height is definitely low for more hail production. PW only at 0.57 BRN shear parameter is low at 24 which doesn’t support supercells though at least in the immediate Davenport area (mainly multicells). Gonna try to watch how this evolves as that environment aloft around there is definitely still interesting. *Edit: 22 Z or utc DVN sounding. ILX sounding just off to the southeast in central IL showing much more CAPE around 1000 & better shear parameters. Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted February 27 Share Posted February 27 Beautiful hook echo on that geneseo cell 1 Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted February 27 Share Posted February 27 Just now, SchaumburgStormer said: Beautiful hook echo on that geneseo cell Link to comment Share on other sites More sharing options...
BYG Jacob Posted February 27 Share Posted February 27 Looks like a TDS Link to comment Share on other sites More sharing options...
metallica470 Posted February 27 Share Posted February 27 1 minute ago, SchaumburgStormer said: Beautiful hook echo on that geneseo cell Just saw that. Looking really interesting now Link to comment Share on other sites More sharing options...
andyhb Posted February 27 Share Posted February 27 Anyone here on that Atkinson storm? Looks pretty close to producing. Link to comment Share on other sites More sharing options...
Stx_Thunder Posted February 27 Share Posted February 27 Number of multicell clusters literally exploded just in the past 30 minutes, just east/south of Davenport IA area. Couple of severe thunderstorm, and tornado warnings now also. Link to comment Share on other sites More sharing options...
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