Indystorm Posted February 20, 2019 Share Posted February 20, 2019 Okay, I'll bite. Both PAH and IND keep talking about possibility of svr on Sat. 12z GFS for Wed. shows 60 degree temps from central IL and IN southward, low 60 dews up the Wabash Valley 114 knot 500 mb jet, relatively low surface CAPE of 438 down by EVV with 400-500 0-3 km helicity and supercell composite of 3. Could be low CAPE, high kinematic event if trends increase. Discuss. Link to comment Share on other sites More sharing options...
vpbob21 Posted February 20, 2019 Share Posted February 20, 2019 This morning's SPC Day 4-8 discussion suggested severe probabilities may need to be expanded northward into the southern Great Lakes. Would be impressive to get a severe threat this far north in February. Link to comment Share on other sites More sharing options...
CheeselandSkies Posted February 20, 2019 Share Posted February 20, 2019 It's happened before...not that long ago. Link to comment Share on other sites More sharing options...
Indystorm Posted February 20, 2019 Author Share Posted February 20, 2019 EURO continues to explosively deepen the surface low pressure as it moves in 24hr from the TX panhandle to upper lower MI from 1001 to 979 mb. Link to comment Share on other sites More sharing options...
CheeselandSkies Posted February 20, 2019 Share Posted February 20, 2019 Been awhile since the central CONUS saw a storm like that if it verifies...too bad I'll likely be too far south for the big time snows and too far north for severe...a not uncommon spot for S. WI/N. IL/E. IA in late winter/early spring. Link to comment Share on other sites More sharing options...
Sydney Claridge Posted February 21, 2019 Share Posted February 21, 2019 NAM is trending weaker and further south over the last few runs, affecting the anticipated moisture return in the lower Ohio Valley and moving the warm front location closer to the Ohio River. It's not much further south, but a weaker storm would lower the potential for severe further north whereas a stronger storm further to the N or NW would allow for more moisture return. Beyond the range of the NAM, it seems that many of the models are suggesting a "Freshwater Fury" storm with pressure dropping to near or below 980 mbar over Ontario. The GFS and GFS-FV3, plus the ECMWF, are displaying a system below 975 mbar. If this storm were to bomb before reaching the Lakes the severe potential would likely be even higher. I would expect the strongest storms to be in the eastern part of my sub (AR and LA) and also W TN and W MS by the looks of things, though. EDIT: SPC is now saying that E AR, the western 2/3 of TN, N MS, and the western half of KY (up to a point SW of Louisville) will be in a Day 3 Enhanced risk at the 30% hatched level; this also includes small slivers of SE MO, S IL, and S IN along the Mississippi and Ohio rivers. Link to comment Share on other sites More sharing options...
CheeselandSkies Posted February 21, 2019 Share Posted February 21, 2019 NAM is a lot farther south and somewhat weaker with the low (at least initially) which would temper the severe potential some but brings a lot more snow into MBY. Suddenly 34 and rain isn't looking like the guaranteed outcome with this system. Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted February 22, 2019 Share Posted February 22, 2019 If anything similar to some of the top 15 CIPS analogs verify Saturday, Central IL could also be in for a very long evening. Some big severe days in and near the current ILX CWA among these analogs: http://www.eas.slu.edu/CIPS/ANALOG/DFHR.php?reg=MV&fhr=F060&rundt=2019022112&map=tbl --#2 analog is 2/20/2014: http://www.eas.slu.edu/CIPS/ANALOG/Event.php?reg=MV&fhr=F060&rundt=2019022112&dt=2014022018 --#4 analog is 3/13/2006 0300 (9PM Mar. 12, 2006--just one hour after the first round of tornadoes hit the south and east sides of Springfield): http://www.eas.slu.edu/CIPS/ANALOG/Event.php?reg=MV&fhr=F060&rundt=2019022112&dt=2006031312 --#10 analog is 1/7/1989 1800--the same day as the F4 Allendale, IL tornado: http://www.eas.slu.edu/CIPS/ANALOG/Event.php?reg=MV&fhr=F060&rundt=2019022112&dt=1989010718 Link to comment Share on other sites More sharing options...
Jim Martin Posted February 22, 2019 Share Posted February 22, 2019 Winds 80+ knots at 850 mb Saturday Night could easily translate to damaging winds 60-70 MPH Saturday Night with the thunderstorm activity. Link to comment Share on other sites More sharing options...
Sydney Claridge Posted February 22, 2019 Share Posted February 22, 2019 And SPC drops the lower Ohio valley from an Enhanced risk all the way down to a Marginal risk for the Day 2 outlook, trimming back the ENH to just north of Memphis, TN. Link to comment Share on other sites More sharing options...
Indystorm Posted February 22, 2019 Author Share Posted February 22, 2019 Yes, SPC is relying heavily upon the NAM with WAA not proceeding as far north as originally thought. My Sat. temp max dropped locally from 60 to 55. Good luck Memphis. Link to comment Share on other sites More sharing options...
Hoosier Posted February 22, 2019 Share Posted February 22, 2019 5 hours ago, Indystorm said: Yes, SPC is relying heavily upon the NAM with WAA not proceeding as far north as originally thought. My Sat. temp max dropped locally from 60 to 55. Good luck Memphis. Have a hard time figuring out why they are following the NAM so closely when it has been struggling with this system (playing catchup). Also, this looks to me like a case where the NAM is again mishandling temps in the warm sector. There is no snowcover to worry about so I see little reason to think that temps won't overperform what the NAM is suggesting. This should help some sfc based instability to get farther north... to what extent is the question of course. Link to comment Share on other sites More sharing options...
hlcater Posted February 22, 2019 Share Posted February 22, 2019 20 minutes ago, Hoosier said: Have a hard time figuring out why they are following the NAM so closely when it has been struggling with this system (playing catchup). Also, this looks to me like a case where the NAM is again mishandling temps in the warm sector. There is no snowcover to worry about so I see little reason to think that temps won't overperform what the NAM is suggesting. This should help some sfc based instability to get farther north... to what extent is the question of course. Because Darrow and the NAM are in an intimate relationship. It’s always been that way. Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 22, 2019 Share Posted February 22, 2019 Luckily SPC adjusted back north again, though still not far enough north.They honestly have been lost ever since the SPC-WRF was discontinued, which they clearly heavily relied on.. Link to comment Share on other sites More sharing options...
Indystorm Posted February 23, 2019 Author Share Posted February 23, 2019 Further north across the Ohio Valley, scattered thunderstorms are forecast to move northeastward into western Kentucky and southern Indiana during the afternoon. Forecast soundings at 21Z for Paducah show MLCAPE near 800 J/kg with 0-6 km shear of 65 kt. This combined with strong low-level shear will be sufficient for severe storms capable of producing tornadoes and wind damage. Most of the severe convection should remain south of the Ohio River. Due to the weaker instability in the Ohio Valley, severe coverage is expected to be less. From SPC day One with moderate risk in TN and northern MS. Link to comment Share on other sites More sharing options...
Indystorm Posted February 23, 2019 Author Share Posted February 23, 2019 SPC has extended the marginal risk northwest across much of southern and central IL and sw IN with a slight risk along the Ohio River in se IL and sw IN primarily for hail. 998 mb surface low now in TX panhandle and expected to cross over IA as it moves ne and rapidly deepens. We'll see what happens with later updates and nowcasts. Could be a significant day for the mid south with tornadoes. I'll want to watch where those elevated storms currently in Arkansas and Missouri are headed wrt our sub forum area. Link to comment Share on other sites More sharing options...
Indystorm Posted February 23, 2019 Author Share Posted February 23, 2019 If any of you have been following the TN valley subforum on svr wx it seems that the NWS has been having multiple problems with software during this severe episode....Polygons are absent or stuck for warnings.....items are not updating.....sheesh! Not a good situation for a moderate risk day at the start of the svr wx season. Link to comment Share on other sites More sharing options...
Indystorm Posted February 24, 2019 Author Share Posted February 24, 2019 Svr t storm east of Galesburg IL....surprise surprise.... 39/39 Other storms popping up in central IL moving ne. Hello, Chi-town. Link to comment Share on other sites More sharing options...
Baum Posted February 24, 2019 Share Posted February 24, 2019 lightning and thunder Link to comment Share on other sites More sharing options...
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