Gilbertfly Posted December 23, 2014 Share Posted December 23, 2014 Nice update by rickey....as always, LOT leading the way on how to handle the trickier situations Link to comment Share on other sites More sharing options...
Thundersnow12 Posted December 23, 2014 Share Posted December 23, 2014 The 12z hi res NMM looks rock solid Link to comment Share on other sites More sharing options...
DAFF Posted December 23, 2014 Share Posted December 23, 2014 Nice update by rickey....as always, LOT leading the way on how to handle the trickier situations +1 Great write up on the SWS. Link to comment Share on other sites More sharing options...
Hoosier Posted December 23, 2014 Share Posted December 23, 2014 Cautiously optimistic for where I'll be in western Lake county IN tomorrow. Still going to be a nowcast event though and will probably be paranoid about a last minute nw tick. Link to comment Share on other sites More sharing options...
A-L-E-K Posted December 23, 2014 Share Posted December 23, 2014 Your RFD to OSH call that you pounded your chest over is in jeopardy. Going to take a last-minute NW jog in defo placement , not unheard of but looking less and less likely based on current conditions. That said, i called RFD to Moneyman ~130 hrs out when everyone was congratulating Detroit. Link to comment Share on other sites More sharing options...
A-L-E-K Posted December 23, 2014 Share Posted December 23, 2014 The 12z hi res NMM looks rock solid I'll take the ARW Link to comment Share on other sites More sharing options...
mimillman Posted December 23, 2014 Share Posted December 23, 2014 Going to take a last-minute NW jog in defo placement , not unheard of but looking less and less likely based on current conditions. That said, i called RFD to Moneyman ~130 hrs out when everyone was congratulating Detroit.I like where we are, but no matter how much I try, I just can't shake that initial concern of mine about accumulations. I think a lot of this will be lost to melting, except under very heavy bands. Especially with the GFS, we're looking at an earlier arrival and warmer temperatures. I will say, it is encouraging to see the Euro so Far East, because I would hate to be running on the eastern fringes on every model for a storm like this. Link to comment Share on other sites More sharing options...
A-L-E-K Posted December 23, 2014 Share Posted December 23, 2014 I like where we are, but no matter how much I try, I just can't shake that initial concern of mine about accumulations. I think a lot of this will be lost to melting, except under very heavy bands. Especially with the GFS, we're looking at an earlier arrival and warmer temperatures. I will say, it is encouraging to see the Euro so Far East, because I would hate to be running on the eastern fringes on every model for a storm like this. I think there are enough signs pointing towards a peak intensity defo band across the CWA. Yes, much of the day will be wet garbage but I think there were be a 3-4 hour window where we could really go to town with wet +SN. Link to comment Share on other sites More sharing options...
Gilbertfly Posted December 23, 2014 Share Posted December 23, 2014 I like where we are, but no matter how much I try, I just can't shake that initial concern of mine about accumulations. I think a lot of this will be lost to melting, except under very heavy bands. Especially with the GFS, we're looking at an earlier arrival and warmer temperatures. I will say, it is encouraging to see the Euro so Far East, because I would hate to be running on the eastern fringes on every model for a storm like this. Rickey via LOT... NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 1037 AM CST TUE DEC 23 2014 .UPDATE... 1037 AM CST CHRISTMAS EVE STORM UPDATE... THE LATEST AVAILABLE 12Z GUIDANCE HAS HONED IN PRETTY CLOSELY ON A LOW PRESSURE TRACK FROM FROM CENTRAL KY TO NEAR IND TO CENTRAL OR SOUTHWEST LOWER MI ON WEDNESDAY. THIS GIVES US MORE CONFIDENCE IN WHERE THE HEAVIEST SWATH OF PRECIPITATION WILL FALL IN THE INTENSE DEFORMATION AXIS. THERE IS A STILL A SIGNIFICANT TIMING DISCREPANCY BETWEEN THE NAM ON THE SLOW END OF THE GUIDANCE ENVELOPE AND 12Z GFS ON THE FASTEST END...AS IT HAS CONSISTENTLY SHOWN FOR SEVERAL MODEL CYCLES. SO CONFIDENCE IS LOWER ON TIMING AND DURATION OF HEAVY PRECIP...WITH THE GFS SUGGESTING THAT THE BULK OF THE PRECIPITATION FALLS BETWEEN 06Z AND 18Z...WHILE THE NAM FAVORS THE HEAVIEST PRECIPITATION OVER THE CHICAGO METRO AND POINTS EAST FROM THE LATE MORNING UNTIL THE LATE AFTERNOON. THE BIGGEST QUESTION MARK REMAINS WITH THE VERY MARGINAL BOUNDARY LAYER CONDITIONS FOR SNOW AT PRECIP ONSET AND THROUGH MUCH OF THE EVENT. PRECIPITATION IS EXPECTED TO START AS RAIN THEN FLIP OVER TO SNOW. THE THINKING IS THAT THE GFS IS NOT HANDLING THE DYNAMIC COOLING OFFERED BY THE INTENSE UPWARD MOTION IN THE HEART OF THE FRONTOGENETICALLY DRIVEN DEFORMATION BAND...AND THUS REMAINS TOO WARM WITH NEAR SFC THERMAL PROFILES AND MOST OF THE PRECIP FALLS IN THE FORM OF RAIN/MIX. THE FORECAST WILL LEAN IN FAVOR OF DYNAMIC COOLING OFFSETTING THE INITIALLY MARGINAL CONDITIONS...WHICH IS CAPTURED WELL BY THE 12Z NAM. HOWEVER...IT WILL LIKELY BE A VERY LOW SNOW TO LIQUID RATIO SNOW AND THE HUGE SNOWFALL AMOUNTS ON THE NAM COBB OUTPUT ARE VERY LIKELY OVERDONE. WOULD LIKE TO SEE THE REST OF THE 12Z GUIDANCE BEFORE MAKING ANY HEADLINE DECISIONS...WHICH WILL LIKELY BE MADE BY THE EARLY AFTERNOON. OVERALL THINKING REMAINS THAT CONFIDENCE IS GROWING IN A HIGH IMPACT SNOW EVENT ACROSS PART OF THE CWA TOMORROW...WHICH IS BECOMING MORE LIKELY TO INCLUDE THE CHICAGO METRO. THE SPS HAS BEEN UPDATED. RC Link to comment Share on other sites More sharing options...
Hoosier Posted December 23, 2014 Share Posted December 23, 2014 Take your pick Link to comment Share on other sites More sharing options...
mimillman Posted December 23, 2014 Share Posted December 23, 2014 Rickey via LOT...Good write-up. I guess my concern is not so much will it snow or not snow, but when it is snowing, how much of it will stick. In my experience, especially in urban areas these rain to snow events with marginal BL temps tend to underperform on the ground. It could be snowing a good deal, but very little would actually accumulate. Link to comment Share on other sites More sharing options...
Gilbertfly Posted December 23, 2014 Share Posted December 23, 2014 Good write-up. I guess my concern is not so much will it snow or not snow, but when it is snowing, how much of it will stick. In my experience, especially in urban areas these rain to snow events with marginal BL temps tend to underperform on the ground. It could be snowing a good deal, but very little would actually accumulate. oh I hear ya... if the rates are there.....well then you just have flakes falling on other flakes before they get a chance to melt....if the rates are marginal then, yeah tough to accumulate on pavement. Some guidance is pointing towards pockets of rates that will do the trick for rapid accumulation Link to comment Share on other sites More sharing options...
A-L-E-K Posted December 23, 2014 Share Posted December 23, 2014 RAP shows a nice defo band developing after things close off at 500, a nice slug of moisture gets yanked northward and UVVs jump. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted December 23, 2014 Share Posted December 23, 2014 Euro continues to be east.. Link to comment Share on other sites More sharing options...
Hoosier Posted December 23, 2014 Share Posted December 23, 2014 Euro continues to be east.. Did the precip shield change at all from 00z? Link to comment Share on other sites More sharing options...
Thundersnow12 Posted December 23, 2014 Share Posted December 23, 2014 RAP shows a nice defo band developing after things close off at 500, a nice slug of moisture gets yanked northward and UVVs jump. Been a nice trend with the NAM and other hi res models closing it off earlier Link to comment Share on other sites More sharing options...
Thundersnow12 Posted December 23, 2014 Share Posted December 23, 2014 Did the precip shield change at all from 00z? Heading into work and just glanced but didn't look like it. Link to comment Share on other sites More sharing options...
Geos Posted December 23, 2014 Share Posted December 23, 2014 EURO keeps almost all the snow in MI and IN. Western 2/3rd's of MI would have a White Christmas if it panned out. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted December 23, 2014 Share Posted December 23, 2014 The 15z RAP is pretty amped as we'd think. 4mb stronger than the NAM at 9z tomorrow with 850s out of the S to SE in the WCB at 55kts...stronger and more backed then the NAM. Would only lead to better precip generation/expansion Link to comment Share on other sites More sharing options...
A-L-E-K Posted December 23, 2014 Share Posted December 23, 2014 on the plus side, it will be pretty obvious by later this evening if the euro is going to pull this one out Link to comment Share on other sites More sharing options...
Thundersnow12 Posted December 23, 2014 Share Posted December 23, 2014 on the plus side, it will be pretty obvious by later this evening if the euro is going to pull this one out It really has no support so I'd be pretty shocked. You'd think a west trend with a deepening upper level system, not east. Link to comment Share on other sites More sharing options...
A-L-E-K Posted December 23, 2014 Share Posted December 23, 2014 12z GEFS do not support the Euro, wettest they have been in the defo in quite a few runs Link to comment Share on other sites More sharing options...
Thundersnow12 Posted December 23, 2014 Share Posted December 23, 2014 12z GEFS do not support the Euro, wettest they have been in the defo in quite a few runs Very nice. Can't do any better than that. Link to comment Share on other sites More sharing options...
A-L-E-K Posted December 23, 2014 Share Posted December 23, 2014 Very nice. Can't do any better than that. OP is actually one of the driest/east of the set Link to comment Share on other sites More sharing options...
mimillman Posted December 23, 2014 Share Posted December 23, 2014 12z GEFS do not support the Euro, wettest they have been in the defo in quite a few runsIndeed, that's a very good signal for an ensemble. I suspect that the 18z runs may come a bit further east, followed by maybe a tick east on the 00z runs as well, but certainly not by any means a compromise to the Euro. Link to comment Share on other sites More sharing options...
harrisale Posted December 23, 2014 Share Posted December 23, 2014 12Z suite. RGEM not depicted but essentially same track as the global. Link to comment Share on other sites More sharing options...
Chicago Storm Posted December 23, 2014 Author Share Posted December 23, 2014 LOT... Link to comment Share on other sites More sharing options...
Brewers Posted December 23, 2014 Share Posted December 23, 2014 Forecasting tonight will be fun. Still thinking MKE will be on the edge of the heaviest snow. Might have to ride this one out in Racine tomorrow. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Thundersnow12 Posted December 23, 2014 Share Posted December 23, 2014 OP is actually one of the driest/east of the set and each of the members is solid hit Link to comment Share on other sites More sharing options...
Thundersnow12 Posted December 23, 2014 Share Posted December 23, 2014 LOT... Ahhh they did add a small 4-6" contour Link to comment Share on other sites More sharing options...
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