Stebo Posted June 19, 2015 Share Posted June 19, 2015 Man the 18z NAM for Monday is off the charts. I'm certain it will change but with the strong jet in the area we have to watch these ripples that would ride the frontal boundary across the area. They would have a high end potential with the wind field that would be in place and the extremely moist low levels just south of the boundary. Link to comment Share on other sites More sharing options...
andyhb Posted June 19, 2015 Share Posted June 19, 2015 Holy friggin hell at the soundings on the 18z NAM on Monday (probably ridiculous, but holy friggin hell). Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 19, 2015 Share Posted June 19, 2015 Holy friggin hell at the soundings on the 18z NAM on Monday (probably ridiculous, but holy friggin hell). Yep thinking that might be my day to chase as I have to work at MDW on Sunday. Link to comment Share on other sites More sharing options...
JasonOH Posted June 19, 2015 Share Posted June 19, 2015 12z also had very high parameters at the same time, but in SW Ohio by Cincy. 12z GFS was further west and not as crazy parameters. Link to comment Share on other sites More sharing options...
andyhb Posted June 19, 2015 Share Posted June 19, 2015 12z also had very high parameters at the same time, but in SW Ohio by Cincy. 12z GFS was further west and no crazy parameters. GFS seemed reasonable enough to me further west in IL and IN. This would be a very potent NW flow setup as it sits right now. Any backing of the surface winds towards the S or even SSW is going to shoot low level SRH through the roof given the strong speed shear in the lowest 3 km. Link to comment Share on other sites More sharing options...
Kaner88 Posted June 19, 2015 Share Posted June 19, 2015 Holy friggin hell at the soundings on the 18z NAM on Monday (probably ridiculous, but holy friggin hell). SHARPpy plot out of KDPA makes for some pretty nice eye candy. Link to comment Share on other sites More sharing options...
andyhb Posted June 19, 2015 Share Posted June 19, 2015 18z GFS is also off the charts in N IL and WI particularly, although I'm wondering if this is related to convective feedback ala that setup last year that was showing EHIs in the high 20s and low 30s due to wind fields that were way overdone. Link to comment Share on other sites More sharing options...
Stebo Posted June 19, 2015 Author Share Posted June 19, 2015 A couple of key features to watch between now and then, the MCS tomorrow needs to go at least southeasterly, if the MCS that forms in Iowa moves due south it would push the front too far south. That would lower Monday's potential as the best moisture would then not colocate with the best winds like the NAM/GFS are showing. Ideally if the MCS moves ESE and dies quickly tomorrow night then the potential for Monday would be higher with the better moisture pushed back in place by late Sunday night. Link to comment Share on other sites More sharing options...
cyclone77 Posted June 19, 2015 Share Posted June 19, 2015 18z GFS is also off the charts in N IL and WI particularly, although I'm wondering if this is related to convective feedback ala that setup last year that was showing EHIs in the high 20s and low 30s due to wind fields that were way overdone. Yeah I remember that. Looking like that could be the case again this time, but if it isn't it looks pretty spooky for those areas. Link to comment Share on other sites More sharing options...
Stebo Posted June 19, 2015 Author Share Posted June 19, 2015 Yeah I remember that. Looking like that could be the case again this time, but if it isn't it looks pretty spooky for those areas. The GFS which had a more tamed wind field still had 0-3km EHIs in the 8-13 range. I would imagine the NAM is overdoing it a bit, but if it isn't this would be a high end potential. Link to comment Share on other sites More sharing options...
cyclone77 Posted June 19, 2015 Share Posted June 19, 2015 The GFS which had a more tamed wind field still had 0-3km EHIs in the 8-13 range. I would imagine the NAM is overdoing it a bit, but if it isn't this would be a high end potential. I was actually mentioning the GFS which has over 80kts at H5 in southern WI at 78hrs. EHI and other parameters off the chart trailing southward from that. Link to comment Share on other sites More sharing options...
nwburbschaser Posted June 19, 2015 Share Posted June 19, 2015 18z GFS is also off the charts in N IL and WI particularly, although I'm wondering if this is related to convective feedback ala that setup last year that was showing EHIs in the high 20s and low 30s due to wind fields that were way overdone. My first thought after looking at the 18z runs today was the 6/30 setup last year. Link to comment Share on other sites More sharing options...
andyhb Posted June 19, 2015 Share Posted June 19, 2015 I was actually mentioning the GFS which has over 80kts at H5 in southern WI at 78hrs. EHI and other parameters off the chart trailing southward from that. I think he meant the more subdued 12z run. It's one of those setups where if you do get some good low level turning, things could get ugly in a hurry. Link to comment Share on other sites More sharing options...
Stebo Posted June 19, 2015 Author Share Posted June 19, 2015 I think he meant the more subdued 12z run. It's one of those setups where if you do get some good low level turning, things could get ugly in a hurry. Yeah sorry, I did mean the 12z run. The key is there should be a huge amount of instability with this, you just need it colocated with the best winds. Link to comment Share on other sites More sharing options...
RCNYILWX Posted June 20, 2015 Share Posted June 20, 2015 18z GFS is also off the charts in N IL and WI particularly, although I'm wondering if this is related to convective feedback ala that setup last year that was showing EHIs in the high 20s and low 30s due to wind fields that were way overdone.A bit OT, but If that's a reference to the June 30th event, it turned out that those wind fields verified. 2 of my coworkers are presenting about that event at the AMS conference in Chicago coming up later this month and I'm a coauthor along with tornadotony. Tony did a KLOT VAD analysis and analysis of a MDW AMDAR sounding, and the SRH with the second qlcs was absolutely insane. 0-3km of 1000 and 0-1km of 700. Of course this doesn't mean the GFS wind fields will verify on Monday however but if we get anything even close to what it and the NAM are showing w.r.t shear/srh and discrete supercells, it goes without saying that we'll be in huge trouble. Link to comment Share on other sites More sharing options...
Hoosier Posted June 20, 2015 Share Posted June 20, 2015 A bit OT, but If that's a reference to the June 30th event, it turned out that those wind fields verified. 2 of my coworkers are presenting about that event at the AMS conference in Chicago coming up later this month and I'm a coauthor along with tornadotony. Tony did a KLOT VAD analysis and analysis of a MDW AMDAR sounding, and the SRH with the second qlcs was absolutely insane. 0-3km of 1000 and 0-1km of 700. Of course this doesn't mean the GFS wind fields will verify on Monday however but if we get anything even close to what it and the NAM are showing w.r.t shear/srh and discrete supercells, it goes without saying that we'll be in huge trouble. It was impressive how much severe wx that produced, especially since the first line moved through not too long before. With that low level shear, you could see that day was going to have potential for quite a few tornadoes even if the mode was linear. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 20, 2015 Share Posted June 20, 2015 Just leave this here for posterity sake. Whether we get storms or not remains to be seen. Link to comment Share on other sites More sharing options...
RyanDe680 Posted June 20, 2015 Share Posted June 20, 2015 Just leave this here for posterity sake. Whether we get storms or not remains to be seen. skittle.gif Wow Link to comment Share on other sites More sharing options...
andyhb Posted June 20, 2015 Share Posted June 20, 2015 Just leave this here for posterity sake. Whether we get storms or not remains to be seen. skittle.gif I don't want to get too into this just yet, but it's worth noting that the NAM is also showing really high parameters on Sunday over the Central Plains. It would make sense that shear would strengthen with the ejecting mid level jet on Monday downstream of this. Link to comment Share on other sites More sharing options...
Hoosier Posted June 20, 2015 Share Posted June 20, 2015 Just leave this here for posterity sake. Whether we get storms or not remains to be seen. skittle.gif Wow, that is dirty. Been a while since I remember seeing a prog like that in our area. MLCAPE of 4000 or so at 21z Mon with those wind fields. Link to comment Share on other sites More sharing options...
OHweather Posted June 20, 2015 Share Posted June 20, 2015 Just from an ingredients based perspective, I'd have to think there's pretty good potential in the sub-forum Monday-Monday night. Fairly persistent low-mid level ridging over the south and especially southwest US through the weekend will allow for strong surface heating over the Rockies/High Plains during the day which will allow a good EML to form...and the strong mid-upper level ridge over the south suggests there won't be much organized convection to overturn that as it moves east on the northern edge of the low-mid level ridging. Closer to the surface, an already moisture rich airmass is in place across much of the south-central and southeastern US, and a persistent anti-cyclonic flow near the central Gulf Coast through the weekend and into early next week will allow more moisture to continue to advect into the Plains and then east towards the Mississippi Valley/OH Valley/Great Lakes. The combination of an EML and moisture rich low levels definitely supports the strong-extreme instability numbers spit out by both the GFS/NAM at this stage outside of any ongoing convection on any given day. In addition to the instability, the combination of the enhanced flow on the northern edge of the mid-upper level ridge over the southern US and shortwaves diving south into central Canada thanks to a fairly stout ridge over Alaska should be enough to cause seasonably strong bulk shear over the northern portion of the very unstable airmass. In addition, the seasonably strong shortwaves should provide enough large scale ascent for areas of surface low pressure to develop that help undulate the quasi-stationary front's position as they go by and also enhance low level shear. So, from just looking at the ingredients potentially in place, things seem lined up for a moderate-high end event somewhere in the subforum Monday-Monday night, although as we get closer mesoscale details/ongoing convection may ultimately throw some wrinkles into that. As has been mentioned...the speed max/shortwave that will move across the upper Mississippi Valley/Great Lakes Monday afternoon-night will eject out into the northern Plains on Sunday, and I'd have to suspect that adequate instability and shear will be in place for an MCS to develop somewhere over maybe SD or NE Sunday evening that moves ESE Sunday night. Although the nose of the 850mb jet is progged to get into southern MN by Monday morning, the shear vectors and MUCAPE gradient Sunday night suggest the MCS will likely track towards IA/MO/IL by Monday morning if it develops. Rich low level moisture...a decent EML...and strong low level jet should allow for quick recovery behind this potential MCS...however, if the MCS dives too far south it may limit moisture return farther east (IE MI/OH). In addition to creating moisture return questions...if the MCS doesn't "get out of the way" quickly enough, getting enough surface heating to break the cap associated with the EML may become harder to do and limit the threat farther south/east. In addition, recent model runs have trended somewhat stronger with the proceeding shortwave over the eastern lakes on Sunday, and are trying to show an interaction with Bill's remnants over the NE Sunday night into Monday. If this shortwave and associated surface low trend stronger/slower, then the surface cold front may get driven farther south Sunday-Sunday night over the eastern portions of the sub forum, also casting some doubt into the magnitude of the threat later Monday farther east. As things stand now, I'd feel decent about some sort of an overnight MCS with at least a marginal severe threat over SD/NE/IA and perhaps into northern MO/parts of IL Sunday evening into Monday morning. For Monday, there's reasonable agreement in the ingredients coming together for a sizable event, with only modest differences in timing of the short wave and associated mid-level speed max. With strong airmass recovery likely behind any nocturnal MCS on Monday and decent shear likely being in place, I'd have to feel fairly decent from eastern IA into WI/ northern IL...shear vectors support some southward component of motion Monday night with whatever the convection grows upscale into which puts lower MI/IN possibly into play and perhaps OH...although farther east questions about timely moisture return do grow some. The one wild card is the cap not breaking if nocturnal stuff hangs around long enough to significantly limit surface heating. So, I see a fairly high end potential and feel fairly good about a decent event occurring somewhere, however I won't feel great until the mesoscale details become clearer. Link to comment Share on other sites More sharing options...
Kaner88 Posted June 20, 2015 Share Posted June 20, 2015 One last bit of eye candy / for posterity, off the 0z GFS for Monday evening at ORD. Link to comment Share on other sites More sharing options...
andyhb Posted June 20, 2015 Share Posted June 20, 2015 00z Euro also has a potent, broad LLJ across the area Monday evening so it's not like this is a one time thing from one model here. However, it's not quite up to the GFS/NAM's level. Link to comment Share on other sites More sharing options...
snowlover2 Posted June 20, 2015 Share Posted June 20, 2015 New day 3 has enhanced area for central WI to central L MI. DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0225 AM CDT SAT JUN 20 2015 VALID 221200Z - 231200Z ..THERE IS AN ENH RISK OF SVR TSTMS ACROSS PARTS OF WI LOWER MI AND LAKE MI... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER MS VALLEY AND GREAT LAKES REGION... ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE NRN PLAINS...MID TO UPPER MS VALLEY...MID MO VALLEY...NRN OH VALLEY AND GREAT LAKES REGION... ..SUMMARY SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES REGION ON MONDAY WHERE A FEW TORNADOES...DAMAGING WIND GUSTS AND ISOLATED LARGE HAIL MAY OCCUR. MARGINALLY SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS THE MID MISSOURI VALLEY...MID TO UPPER MISSISSIPPI VALLEY AND NORTHERN OHIO VALLEY. ..UPPER MS VALLEY/GREAT LAKES REGION A VIGOROUS SHORTWAVE TROUGH IS FORECAST TO MOVE ACROSS THE UPPER MS VALLEY ON MONDAY AS AN IMPRESSIVE 60 TO 80 KT MID-LEVEL JET MOVES EWD INTO THE GREAT LAKES REGION. AT THE SFC...A COLD FRONT IS FORECAST TO ADVANCE SEWD ACROSS WI AND IA WITH A MOIST AND UNSTABLE AIRMASS LOCATED AHEAD OF THE FRONT FROM THE OH VALLEY INTO THE SRN GREAT LAKES REGION. A CLUSTER OF THUNDERSTORMS MAY BE ONGOING AT DAYBREAK ON MONDAY IN THE UPPER MS VALLEY NEAR THE NOSE OF A 40 TO 50 KT LOW-LEVEL JET. THIS CONVECTION IS FORECAST TO TRACK EWD INTO THE GREAT LAKES REGION AND MAY LAY DOWN AN OUTFLOW BOUNDARY IMPORTANT FOR THE DEVELOPMENT OF AFTERNOON CONVECTION. ALTHOUGH MESOSCALE FACTORS SHOULD BE IMPORTANT FOR SETTING UP THE MOST IDEAL CORRIDOR FOR SEVERE...THE SYNOPTIC-SCALE SYSTEM APPEARS QUITE ORGANIZED AND MAY BE FAVORABLE FOR A REGIONAL SEVERE WEATHER EVENT. NAM AND GFS FORECAST SOUNDINGS FROM MADISON WI EWD INTO SW LOWER MI AT 00Z/TUESDAY SHOW STRONG TO EXTREME INSTABILITY PROFILES WITH IMPRESSIVE WIND FIELDS. 0-6 KM SHEAR IS FORECAST TO BE IN THE 60 TO 80 KT RANGE ACROSS MUCH OF THE GREAT LAKES REGION LATE MONDAY AFTERNOON. THE STRONG DEEP-LAYER SHEAR AND LOOPED HODOGRAPHS SUGGEST THAT SUPERCELLS AND TORNADOES WILL BE POSSIBLE. 0-3 KM STORM RELATIVE HELICITIES ABOVE 400 M2/S2 COULD BE FAVORABLE FOR A COUPLE STRONG TORNADOES AS WELL. AS CELLS INCREASE IN COVERAGE AND ORGANIZE INTO AN MCS...THE WIND DAMAGE POTENTIAL SHOULD BECOME ENHANCED ACROSS PARTS OF WI AND LOWER MI WHERE WIND GUSTS ABOVE 65 KTS WILL BE POSSIBLE. ALTHOUGH THE NAM AND GFS PRESENT AGGRESSIVE SOLUTIONS FOR MONDAY...THE ECMWF IS MORE CONSERVATIVE CONCERNING INSTABILITY IN THE GREAT LAKES REGION AND SHOWS A MUCH WEAKER LOW-LEVEL JET. ALSO...WILL NEED RUN TO RUN CONSISTENCY TO INCREASE CONFIDENCE CONCERNING THIS SETUP. ALTHOUGH A SEVERE WEATHER EVENT WILL BE POSSIBLE MONDAY AFTERNOON AND EVENING...UNCERTAINTY REMAINS TOO GREAT TO WARRANT ISSUING ANYTHING ABOVE AN ENHANCED RISK. ..BROYLES.. 06/20/2015 Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted June 20, 2015 Share Posted June 20, 2015 I can honestly see that Day 3 Slight being expanded WAY farther south and the Enhanced being expanded. I honestly don't know why they didn't do it today. Link to comment Share on other sites More sharing options...
Stebo Posted June 20, 2015 Author Share Posted June 20, 2015 Using the euro for instability is going to be a fail, it has grossly underdone instability all severe season, sometimes by as much as 2000 j/kg. I can understand the uncertainty at this point but the reasoning is a bit suspect considering the euro's failure all season long. Link to comment Share on other sites More sharing options...
andyhb Posted June 20, 2015 Share Posted June 20, 2015 Looking at the Euro's destabilization on Monday in IL in particular, a few things aren't making sense. We have a healthy EML with 7-8+ C/km mid level lapse rates overspreading low-mid 70s dews (perfectly reasonable for this time of year) at 00z and yet all I see is 2000-3000 J/kg CAPE with pockets of 3000-4000 J/kg from around Springfield to Champaign. That really doesn't make much sense whatsoever. I can understand the questions about LLJ/wind field strength, but destabilization and perhaps extreme destabilization should really not be a problem south of wherever the warm front sets up. Link to comment Share on other sites More sharing options...
A-L-E-K Posted June 20, 2015 Share Posted June 20, 2015 Monday looks good at this point but we have at least 2 more large mcs to get through first. Smart money says the effective warm front ends up well south of current guidance Link to comment Share on other sites More sharing options...
Powerball Posted June 20, 2015 Share Posted June 20, 2015 Hopefully, capping isn't too much of an issue also on Monday. 12z NAM shows widespread 700mb temps of 15*C where the best instability lies... Link to comment Share on other sites More sharing options...
nwburbschaser Posted June 20, 2015 Share Posted June 20, 2015 Is that a sup composite of 100 on the 12z NAM? Link to comment Share on other sites More sharing options...
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