The_Global_Warmer Posted January 4, 2014 Share Posted January 4, 2014 850mb closes off just West of STL at hr 30 Link to comment Share on other sites More sharing options...
Central Illinois Posted January 4, 2014 Share Posted January 4, 2014 NAM looks impressive through 36hrs Link to comment Share on other sites More sharing options...
mimillman Posted January 4, 2014 Share Posted January 4, 2014 Rescheduled my flight to get in at 9:45 tonight in Chicago. Otherwise, it's curtains for me and I'll be stuck in Toronto. Link to comment Share on other sites More sharing options...
Hoosier Posted January 4, 2014 Share Posted January 4, 2014 Between the initial snows and the main system snows, the 6z NAM crushes Chicago. Link to comment Share on other sites More sharing options...
Chicago Storm Posted January 4, 2014 Author Share Posted January 4, 2014 In the end the SLP tracks to the same spot as the 0z run...Near the IN/KY/OH border area. Precip shield is farther NW still though. Link to comment Share on other sites More sharing options...
Chicago Storm Posted January 4, 2014 Author Share Posted January 4, 2014 Between the initial snows and the main system snows, the 6z NAM crushes Chicago. Geos will not be denied. Link to comment Share on other sites More sharing options...
Chicago Storm Posted January 4, 2014 Author Share Posted January 4, 2014 0.90"+ QPF near Aleks hood and ORD. Link to comment Share on other sites More sharing options...
Hoosier Posted January 4, 2014 Share Posted January 4, 2014 This run does look a bit warmer...in fact much of IN S of I-70 gets screwed. Link to comment Share on other sites More sharing options...
Hoosier Posted January 4, 2014 Share Posted January 4, 2014 In the end the SLP tracks to the same spot as the 0z run...Near the IN/KY/OH border area. Precip shield is farther NW still though. Track is a bit farther west after that... Link to comment Share on other sites More sharing options...
Sidewinder Posted January 4, 2014 Share Posted January 4, 2014 KIND getting ready to upgrade to a warning, still going 6-12 with higher accumulations in the nw forecast area http://forecast.weather.gov/product.php?site=IND&issuedby=IND&product=AFD&format=CI&version=1&glossary=1 Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 4, 2014 Share Posted January 4, 2014 12" lolli for a decent sized area on this run for myself, Joe, Alek, ORD and MDW. Link to comment Share on other sites More sharing options...
Chicago Storm Posted January 4, 2014 Author Share Posted January 4, 2014 Track is a bit farther west after that... Indeed. Started NW, went similar, then went back west. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted January 4, 2014 Share Posted January 4, 2014 Given the nam is way to fast by 3-6 hours. there will be more expansion of QPF as we go on. As far as track I wouldn't expect it to go much further West as much as the Cold side will be wetter. It may cut faster as it passes KY/IN Link to comment Share on other sites More sharing options...
Radtechwxman Posted January 4, 2014 Share Posted January 4, 2014 Does anyone have the snow map yet for 06z nam? Link to comment Share on other sites More sharing options...
Hoosier Posted January 4, 2014 Share Posted January 4, 2014 Does anyone have the snow map yet for 06z nam? Link to comment Share on other sites More sharing options...
RCNYILWX Posted January 4, 2014 Share Posted January 4, 2014 This may not be as good a system to use this as a proxy for, but typically the location of the potential vorticity (PV) anomaly hook is a decent telltale for a farther northwest track of a synoptic system. It worked very well with the November 17th tornado outbreak and also the 12/21-12/22 storm. Big difference here is the likelihood of less warm sector convection. Nonetheless, I plotted the 500-300 mb PVU surface (used that layer because the tropopause is going to be much lower in this setup than usual) at work this evening and for both the GFS (18z) and the Euro (12z) the location of the PV hook for each suggested a slightly farther northwest track is possible, with the "hook" pointing to southwest IL then into southwest IN in general. In a talk that Victor Gensini of COD and NIU gave at our winter weather workshop (that I mentioned before 11/17), he specifically referenced GHD in that the GFS consistently placed the SLP well east of the PV anomaly, while interestingly enough, within 24 hours the NAM handled this better even though it's not a global model. Result was the farther NW track that brought the sleet apocalypse just southeast of the deformation axis snows and a bust for the blizzard warning for much of the STL area. The NAM clearly is an inconsistent model, but it *should* have a better handle with things like the fgen snows over northern IL behind the surface front because the frontogenetic circulation is more of a mesoscale feature. For the synoptic system, we'll have to see, there's valid reasons mentioned earlier how there's a limit on how far NW it can go, but I'm continuing to favor a track a bit northwest of the Euro and especially the GFS. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted January 4, 2014 Share Posted January 4, 2014 Link to comment Share on other sites More sharing options...
Radtechwxman Posted January 4, 2014 Share Posted January 4, 2014 Thanks Hoosier!! Wow that was a huge shift north. Either nam is onto something or it is a major outlier. What do you guys think? Hard to ignore the consistency of gfs/euro but they are long range models and nam is in its good range. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted January 4, 2014 Share Posted January 4, 2014 RAP is still gearing up to drop a bomb. Link to comment Share on other sites More sharing options...
Radtechwxman Posted January 4, 2014 Share Posted January 4, 2014 Interesting how there is two seperate bands on nam. Makes me wonder if we get secondary low dev further north. Or the front gets hung up north. That would also allow the main system to progress further nw Link to comment Share on other sites More sharing options...
snowlover2 Posted January 4, 2014 Share Posted January 4, 2014 Model Disco including Euro. MODEL DIAGNOSTIC DISCUSSIONNWS WEATHER PREDICTION CENTER COLLEGE PARK MD142 AM EST SAT JAN 04 2014VALID JAN 04/0000 UTC THRU JAN 07/1200 UTC...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIRINGEST...00Z MODEL EVALUATION INCLUDING FINAL PREFERENCES~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORTRANGE FORECASTS.NORTHERN STREAM SHORTWAVE TROUGH/SURFACE LOW(S) IMPACTING THEN-CNTRL U.S. TODAYCOLD FRONT CROSSING THE CENTRAL U.S.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~PREFERENCE: NON 00Z NAM COMPROMISECONFIDENCE: ABOVE AVERAGETHE GUIDANCE IS IN GOOD AGREEMENT OUTSIDE OF THE 00Z NAM WHICHSLOWED DOWN WITH THE MID-LEVEL SHORTWAVE EARLY TODAY OVER THEN-CNTRL STATES. THE PREVIOUS 12Z NAM APPEARED OKAY AND IT IS NOTCLEAR WHY THE RECENT NAM SHIFTED SLOWER. REMAINING MODEL GUIDANCEFORMS A GOOD COMPROMISE.BURGEONING TROUGH MID-CONTINENTSURFACE LOW TRACKING FROM THE SRN PLAINS TO THE LOWER GREAT LAKESFROM SAT THROUGH MON~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~PREFERENCE: 00Z ECMWF/CANADIAN/GFS COMPROMISECONFIDENCE: AVERAGETHE ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT WITH A SURFACELOW EXPECTED TO TRACK FROM THE SRN PLAINS INTO QUEBEC BY MONMORNING...WITH THE EC...GEFS...AND CMC MEMBERS MOSTLY AGREEING ONA POSITION NOW. THE 00Z UKMET ADJUSTED QUICKER FROM ITS 12ZRUN...BUT IS STILL SLOWER THAN THE CONSENSUS...WHILE THE NAM ISTHE STRONGEST OF THE DETERMINISTIC MODELS. THE 00Z GFS/ECMWF/CMCHAVE GOOD AGREEMENT AND REPRESENT THE BEST COMPROMISE OF THECURRENT AVAILABLE MODELS. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted January 4, 2014 Share Posted January 4, 2014 This may not be as good a system to use this as a proxy for, but typically the location of the potential vorticity (PV) anomaly hook is a decent telltale for a farther northwest track of a synoptic system. It worked very well with the November 17th tornado outbreak and also the 12/21-12/22 storm. Big difference here is the likelihood of less warm sector convection. Nonetheless, I plotted the 500-300 mb PVU surface (used that layer because the tropopause is going to be much lower in this setup than usual) at work this evening and for both the GFS (18z) and the Euro (12z) the location of the PV hook for each suggested a slightly farther northwest track is possible, with the "hook" pointing to southwest IL then into southwest IN in general. In a talk that Victor Gensini of COD and NIU gave at our winter weather workshop (that I mentioned before 11/17), he specifically referenced GHD in that the GFS consistently placed the SLP well east of the PV anomaly, while interestingly enough, within 24 hours the NAM handled this better even though it's not a global model. Result was the farther NW track that brought the sleet apocalypse just southeast of the deformation axis snows and a bust for the blizzard warning for much of the STL area. The NAM clearly is an inconsistent model, but it *should* have a better handle with things like the fgen snows over northern IL behind the surface front because the frontogenetic circulation is more of a mesoscale feature. For the synoptic system, we'll have to see, there's valid reasons mentioned earlier how there's a limit on how far NW it can go, but I'm continuing to favor a track a bit northwest of the Euro and especially the GFS. This is how all of the local mets in STL feel and why Chris Higgins has this. But I am sure we can use our imagination bending the 8-12 band towards LAF just a bit. If the stronger more NW solutions verify there could be a historic 12-18" band from STL to between Indy/Laf. I would ignore East of the STL metro. Reasoning: After pouring through the data... the changes I'm making are very limited. The key features...especially the 850mb low and the 500mb vort max are all handled in a very similar fashion. The consensus 850mb low track is still from southwest MO corner...east/northeast to near or just north of Fredericktown, MO....up over Perryville, MO...then northeast to near Mount Vernon. The 500mb vort max tracks are a little more squirrely...especially on the GFS...but the general average takes the center of the vort max out of OK up into far south-centeral MO...then up over Poplar Bluff...then really stretches it out as it moves over to Paducah. Using those two tracks as a guide...per the GYB technique... still puts the axis of heavy snow further north from virtually every model QPF output...arguing for something along the lines of Nevada MO... through about Jeff City...up to near Alton, IL...then east/northeast from there. As our good friend Fred Glass mentioned in his AFD... the snow may end up closer to the 850mb low track due to the artic air mass...which is certainly possible. With that in mind... I have decided to ease the southern edge of my 8-12" range ever so slightly further south...while holding firm on the north end...consistent with the GYB technique. It is extremely rare to get significant snow southeast of the track of the 850mb low...so I will use that as the limit of my 5-8" band...with the 500mb vort track serving as my southern most accumulating snow boundary. The northern edge of the accumulating snow will be rather sharp...which is not unusual. Using the 700mb chart from the GEM and Euro offers a good idea of where that sharp cut off should be...just north of the strong troughing/convergence zone...or from about halfway between Quincy and Bowling Green...down to just west of Columbia. Link to comment Share on other sites More sharing options...
Radtechwxman Posted January 4, 2014 Share Posted January 4, 2014 I cant blame hpc for picking those models b/c they have been most consistent and most likely right. But hard to ignore that hi-res/short term models like nam and rap are picking up on a stronger/more nw system Link to comment Share on other sites More sharing options...
Stebo Posted January 4, 2014 Share Posted January 4, 2014 This may not be as good a system to use this as a proxy for, but typically the location of the potential vorticity (PV) anomaly hook is a decent telltale for a farther northwest track of a synoptic system. It worked very well with the November 17th tornado outbreak and also the 12/21-12/22 storm. Big difference here is the likelihood of less warm sector convection. Nonetheless, I plotted the 500-300 mb PVU surface (used that layer because the tropopause is going to be much lower in this setup than usual) at work this evening and for both the GFS (18z) and the Euro (12z) the location of the PV hook for each suggested a slightly farther northwest track is possible, with the "hook" pointing to southwest IL then into southwest IN in general. In a talk that Victor Gensini of COD and NIU gave at our winter weather workshop (that I mentioned before 11/17), he specifically referenced GHD in that the GFS consistently placed the SLP well east of the PV anomaly, while interestingly enough, within 24 hours the NAM handled this better even though it's not a global model. Result was the farther NW track that brought the sleet apocalypse just southeast of the deformation axis snows and a bust for the blizzard warning for much of the STL area. The NAM clearly is an inconsistent model, but it *should* have a better handle with things like the fgen snows over northern IL behind the surface front because the frontogenetic circulation is more of a mesoscale feature. For the synoptic system, we'll have to see, there's valid reasons mentioned earlier how there's a limit on how far NW it can go, but I'm continuing to favor a track a bit northwest of the Euro and especially the GFS. Great post and great thoughts, I have to agree with you here especially about the fgen. If I had to pick a track with the synoptic system I would probably pick something close to the RGEM from 00z maybe a touch east of that. The NAM is a bit unrealistically left on this one, and like we have seen all winter, will correct east some throughout the day today. Like you mention though, I also agree the GFS/Euro combo is a bit too far east on this one and will probably correct left a bit throughout the day. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 4, 2014 Share Posted January 4, 2014 Stallin' city Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted January 4, 2014 Share Posted January 4, 2014 06z RGEM is coming in much stronger and more NW than 18z. Link to comment Share on other sites More sharing options...
Chicago Storm Posted January 4, 2014 Author Share Posted January 4, 2014 6z RGEM is coming in NW again too. Link to comment Share on other sites More sharing options...
Stebo Posted January 4, 2014 Share Posted January 4, 2014 06z RGEM is coming in much stronger and more NW than 18z. Lows are in the same spot at 24hr vs 30hr/36hr on 00/18z. It is 1mb stronger, I wouldn't call that much stronger. Link to comment Share on other sites More sharing options...
on_wx Posted January 4, 2014 Share Posted January 4, 2014 GRR issued winter storm warnings for SE counties Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted January 4, 2014 Share Posted January 4, 2014 Lows are in the same spot at 24hr vs 30hr/36hr on 00/18z. It is 1mb stronger, I wouldn't call that much stronger. Look at the upper level dynamics everything is easily 50-75 miles North. Link to comment Share on other sites More sharing options...
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