tornadotony Posted October 1, 2013 Share Posted October 1, 2013 This is honestly probably the most significant fall severe weather threat I can recall since maybe October 2007, perhaps even November 2005 (will probably exceed 11/29/10 IMO). It's not every day you see a good EML ride up above a warm sector with huge, looping hodographs and 65°F or higher sfc dewpoints. The main questions IMO are still low track and speed, which will likely affect the location of the greatest threat moreso than the level of threat itself. Verbatim the GFS has a significant threat over much of IA, while the faster NAM has an extremely impressive threat focused over SE MN/NE IA/SW WI. Link to comment Share on other sites More sharing options...
AgeeWx Posted October 1, 2013 Share Posted October 1, 2013 I agree. I think as long as the cap remains stout throughout the day, once the forcing arrives we could see some significant, rotating storms. D4 mentions possibility for strong tornadoes. Link to comment Share on other sites More sharing options...
AgeeWx Posted October 1, 2013 Share Posted October 1, 2013 Also of note, (not necessarily in this thread) are the snow chances for the Dakotas behind this system. Gonna be a fun weekend. Link to comment Share on other sites More sharing options...
Quincy Posted October 1, 2013 Share Posted October 1, 2013 The timing is in question as the models have consistently been slowing down. Now the Euro doesn't even bring the low into SW Iowa until 6z Saturday. The whole evolution of this thing is probably going to change, but at face value, the 12z NAM and GFS were quite impressive. Link to comment Share on other sites More sharing options...
Chinook Posted October 1, 2013 Share Posted October 1, 2013 Replying to Tornadotony Remember the Octobomb of 2010, many tornadoes and wind damage reports http://www.spc.noaa.gov/climo/reports/101026_rpts.html This shows 402 storm reports 69 confirmed tornadoes, according to Wikipedia, for the October 23-27 time period http://en.wikipedia.org/wiki/October_2010_North_American_storm_complex Link to comment Share on other sites More sharing options...
tornadotony Posted October 1, 2013 Author Share Posted October 1, 2013 Replying to Tornadotony Remember the Octobomb of 2010, many tornadoes and wind damage reports http://www.spc.noaa.gov/climo/reports/101026_rpts.html This shows 402 storm reports 69 confirmed tornadoes, according to Wikipedia http://en.wikipedia.org/wiki/October_2010_North_American_storm_complex None of them were higher than EF2... Link to comment Share on other sites More sharing options...
thewxmann Posted October 1, 2013 Share Posted October 1, 2013 12Z Euro much slower... focus is slowly shifting towards the central Plains near and west of the Missouri River. Link to comment Share on other sites More sharing options...
brettjrob Posted October 1, 2013 Share Posted October 1, 2013 As Quincy alluded to, 12z ECMWF really threw a curveball with a dramatically slower solution. Friday's threat would be centered more over E NE/W IA verbatim. Curious that none of the other 12z modeling looks remotely similar in terms of slowing down, so I'll wait until tonight before giving this much weight. Link to comment Share on other sites More sharing options...
Chinook Posted October 1, 2013 Share Posted October 1, 2013 As Quincy alluded to, 12z ECMWF really threw a curveball with a dramatically slower solution. Friday's threat would be centered more over E NE/W IA verbatim. Curious that none of the other 12z modeling looks remotely similar in terms of slowing down, so I'll wait until tonight before giving this much weight. Slower could mean a longer snow event... I like warm weather in October. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted October 1, 2013 Share Posted October 1, 2013 This almost looks like a repeat of earlier this spring with a strong anafront surging south. If that verifies I don't anticipate this being a sig threat if the dryline is cut off with that surging front. Timing is obviously an issue, however. Link to comment Share on other sites More sharing options...
Chicago Storm Posted October 1, 2013 Share Posted October 1, 2013 This almost looks like a repeat of earlier this spring with a strong anafront surging south. If that verifies I don't anticipate this being a sig threat if the dryline is cut off with that surging front. Timing is obviously an issue, however. None of the models have yet to show that exact solution...Though the 12z ECMWF did go towards that direction. Link to comment Share on other sites More sharing options...
andyhb Posted October 1, 2013 Share Posted October 1, 2013 This almost looks like a repeat of earlier this spring with a strong anafront surging south. If that verifies I don't anticipate this being a sig threat if the dryline is cut off with that surging front. Timing is obviously an issue, however. Yeah I was thinking this same thing concerning the 12z Euro, 2013 trends die hard. Link to comment Share on other sites More sharing options...
thewxmann Posted October 1, 2013 Share Posted October 1, 2013 This almost looks like a repeat of earlier this spring with a strong anafront surging south. If that verifies I don't anticipate this being a sig threat if the dryline is cut off with that surging front. Timing is obviously an issue, however. The surging front is almost certainly going to be an issue further south. The area near the surface low is where the most significant threat will be (as long as crapvection doesn't ruin everything). Link to comment Share on other sites More sharing options...
Stebo Posted October 1, 2013 Share Posted October 1, 2013 This is honestly probably the most significant fall severe weather threat I can recall since maybe October 2007, perhaps even November 2005 (will probably exceed 11/29/10 IMO). It's not every day you see a good EML ride up above a warm sector with huge, looping hodographs and 65°F or higher sfc dewpoints. The main questions IMO are still low track and speed, which will likely affect the location of the greatest threat moreso than the level of threat itself. Verbatim the GFS has a significant threat over much of IA, while the faster NAM has an extremely impressive threat focused over SE MN/NE IA/SW WI. Funny you bring up October 2007, 00z CIPS analog centered on the Great Lakes at 120hr out, that event was the top analog, 12z it did fall down the list a bit though. Link to comment Share on other sites More sharing options...
andyhb Posted October 2, 2013 Share Posted October 2, 2013 00z GFS coming in with an 80-90 kt H5 jet max rounding the base of the trough 18z Friday. Verbatim...Eastern NE and much of IA look to get lit up. LLJ is already 40+ kts over IA at 21z, intensifying to 50 kts by 00z. More importantly model continuity wise, the GFS appears to be maintaining its timing. That sweet spot on the nose of the incoming H5 jet looks very impressive. Link to comment Share on other sites More sharing options...
brettjrob Posted October 2, 2013 Share Posted October 2, 2013 My interpretation: GFS looks impressive both Thu-Fri (more conditional on the former). NAM looks iffy for both, though even it may slam E IA/SE MN/SW WI on Friday afternoon. I know many will cling to the "NAM worthless outside 36" meme, but I'm weighing its solution about 75% for now and assuming a more progressive verification than the GFS. Link to comment Share on other sites More sharing options...
Chicago Storm Posted October 2, 2013 Share Posted October 2, 2013 My interpretation: GFS looks impressive both Thu-Fri (more conditional on the former). NAM looks iffy for both, though even it may slam E IA/SE MN/SW WI on Friday afternoon. I know many will cling to the "NAM worthless outside 36" meme, but I'm weighing its solution about 75% for now and assuming a more progressive verification than the GFS. I wouldn't be so sure, Re: NAM meme. The NAM is still playing catch-up, with a decent shift slower between the 12/0z runs. I do agree though that things will probably be more progressive than the GFS...Probably an average of the GFS/NAM. Link to comment Share on other sites More sharing options...
thewxmann Posted October 2, 2013 Share Posted October 2, 2013 My interpretation: GFS looks impressive both Thu-Fri (more conditional on the former). NAM looks iffy for both, though even it may slam E IA/SE MN/SW WI on Friday afternoon. I know many will cling to the "NAM worthless outside 36" meme, but I'm weighing its solution about 75% for now and assuming a more progressive verification than the GFS. Not sure Brett... dprog/dt is favoring a slower solution and the GFS/ECMWF combo trumps >36 hr NAM any day. Link to comment Share on other sites More sharing options...
tornadotony Posted October 2, 2013 Author Share Posted October 2, 2013 Not sure Brett... dprog/dt is favoring a slower solution and the GFS/ECMWF combo trumps >36 hr NAM any day. And even if the NAM were to verify, it frankly obliterates the Des Moines-Decorah-La Crosse corridor. Link to comment Share on other sites More sharing options...
thewxmann Posted October 2, 2013 Share Posted October 2, 2013 Ughh... 0Z Euro continues to trend towards the anafront scenario with a more strung out surface low. Could throw a major curveball here. Link to comment Share on other sites More sharing options...
tornadotony Posted October 2, 2013 Author Share Posted October 2, 2013 Ughh... 0Z Euro continues to trend towards the anafront scenario with a more strung out surface low. Could throw a major curveball here. Why are we really putting much stock in the Euro? First it's the fastest model, then it's the slowest, now it's the weakest...once it actually has a run that is consistent with its previous run, maybe I'll think about it. Until then, the GFS and NAM are starting to line up pretty well, and each run, the threat level on them only goes up. And even with the Euro solution, you'd still have significant severe convection over ern NE and IA. Link to comment Share on other sites More sharing options...
Stebo Posted October 2, 2013 Share Posted October 2, 2013 Why are we really putting much stock in the Euro? First it's the fastest model, then it's the slowest, now it's the weakest...once it actually has a run that is consistent with its previous run, maybe I'll think about it. Until then, the GFS and NAM are starting to line up pretty well, and each run, the threat level on them only goes up. And even with the Euro solution, you'd still have significant severe convection over ern NE and IA. I completely agree with this, the fact that the Euro has no run to run consistency is a big tell. I wouldn't entirely toss it but I certainly wouldn't base my forecast upon it either. The GFS has had very good run to run consistency with the synoptic scale features other than it has been slowing down a touch as we have gone day to day. As you stated though with respect to Euro, it still has significant potential to it, only the ceiling isn't as high as the GFS and NAM solutions. Link to comment Share on other sites More sharing options...
Minnesota Meso Posted October 2, 2013 Share Posted October 2, 2013 The 30/12z NAM holds true to the 30/0z run taking the surface low west of MSP.. It really wants to clock the area from Albert Lea, Owatonna east to Rochester MN. 0-3 km helicity approaching 500, with 0-1km up to 250. Link to comment Share on other sites More sharing options...
tornadotony Posted October 2, 2013 Author Share Posted October 2, 2013 The 30/12z NAM holds true to the 30/0z run taking the surface low west of MSP.. It really wants to clock the area from Albert Lea, Owatonna east to Rochester MN. 0-3 km helicity approaching 500, with 0-1km up to 250. Yeah the forcasted shear/instability combo along the IA/MN border Friday is jawdropping, especially the low-level turning. Link to comment Share on other sites More sharing options...
Stebo Posted October 2, 2013 Share Posted October 2, 2013 Yeah the forcasted shear/instability combo along the IA/MN border Friday is jawdropping, especially the low-level turning. Albert Lea area at 00z Saturday The amount of speed and directional shear in the lowest 75mb is really incredible as you stated. Link to comment Share on other sites More sharing options...
Quincy Posted October 2, 2013 Share Posted October 2, 2013 While the Euro may be a bit out to lunch with its depiction, I think we can agree that there is at least a subtle trend slower/further west. The 12z NAM and GFS both showed this, yet still seem to be highlighting Iowa and surrounding areas. Link to comment Share on other sites More sharing options...
Stebo Posted October 2, 2013 Share Posted October 2, 2013 While the Euro may be a bit out to lunch with its depiction, I think we can agree that there is at least a subtle trend slower/further west. The 12z NAM and GFS both showed this, yet still seem to be highlighting Iowa and surrounding areas. Yeah the 12z GFS has slowed a touch more, centering the potential from Lincoln NE to Des Moines IA. Link to comment Share on other sites More sharing options...
brettjrob Posted October 2, 2013 Share Posted October 2, 2013 12z GFS and NAM are awfully impressive, only disagreeing on the longitudinal bullseye for the most part. The the GFS scenario for Omaha on Friday is easily the most ominous look I've seen there in a few years. Link to comment Share on other sites More sharing options...
Quincy Posted October 2, 2013 Share Posted October 2, 2013 The Euro will be interesting. The Canadian stopped from the slower trend and is actually closer to the NAM/GFS now. Link to comment Share on other sites More sharing options...
brettjrob Posted October 2, 2013 Share Posted October 2, 2013 The Euro will be interesting. The Canadian stopped from the slower trend and is actually closer to the NAM/GFS now. Not sure I agree entirely on the 12z Canadian. It still has the H5 low centered at Cheyenne by 00z Sat and the surface low is in south-central NE. Also, verbatim, no warm sector QPF by that time. It's hard to imagine a cap bust Friday -- the extreme slow end of the guidance envelope would have to win out. If we're converging on something close to the 12z GFS, that may be the most ominous scenario, putting OMA-DMX in play with late afternoon initiation likely. Link to comment Share on other sites More sharing options...
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