gosaints Posted December 23, 2014 Report Share Posted December 23, 2014 NAM will be east, I hear this means all snow for ChicagoEast probably means weaker and less snow Quote Link to comment Share on other sites More sharing options...
BigDizBliz420 Posted December 23, 2014 Report Share Posted December 23, 2014 and less rain LOT says heavy snow Quote Link to comment Share on other sites More sharing options...
gosaints Posted December 23, 2014 Report Share Posted December 23, 2014 and less rain LOT says heavy snowLol rain at hour 27 Quote Link to comment Share on other sites More sharing options...
Scott26 Posted December 23, 2014 Report Share Posted December 23, 2014 12Z NAM is nice. It even gives the Milwaukee people some hope still. Quote Link to comment Share on other sites More sharing options...
gosaints Posted December 23, 2014 Report Share Posted December 23, 2014 12Z NAM is nice. It even gives the Milwaukee people some hope still.Ya lost its crazy qpf amounts that were being pushed last night but good track for lots of the board Quote Link to comment Share on other sites More sharing options...
BigDizBliz420 Posted December 23, 2014 Report Share Posted December 23, 2014 Looks like heavy snow for the heart of Chitown Lot said convection so looks like thundersnow likely for the city! in this bad for sure http://www.tropicaltidbits.com/analysis/models/nam/2014122312/nam_mslp_pcpn_frzn_us_9.png Quote Link to comment Share on other sites More sharing options...
BigDizBliz420 Posted December 23, 2014 Report Share Posted December 23, 2014 I think the 4km NAM will be good for east but bad for wisconsin people Quote Link to comment Share on other sites More sharing options...
gosaints Posted December 23, 2014 Report Share Posted December 23, 2014 I think the 4km NAM will be good for east but bad for wisconsin peopleTo warm in Chicago . western suburbs much better Quote Link to comment Share on other sites More sharing options...
BigDizBliz420 Posted December 23, 2014 Report Share Posted December 23, 2014 To warm in Chicago . western suburbs much better I live in Naperville is that far west enough? This doesn't look too warm for Chicago, are LOT not seeing some warm layer? http://mag.ncep.noaa.gov/data/nam-hires/12/nam-hires_namer_030_850_temp_mslp_precip.gif Quote Link to comment Share on other sites More sharing options...
Tom Posted December 23, 2014 Author Report Share Posted December 23, 2014 LOT has already taken the warm layer into consideration... THE RAPID DEEPENING AND QUICK MOVEMENT OF THE MID/UPPER LEVEL LOWWILL LIKELY RESULT IN EXTREMELY IMPRESSIVE LARGE SCALE FORCING WITHAN IMPRESSIVE TROWAL/DEFORMATION ZONE LIKELY TO DEVELOP ON THEWESTERN FLANK OF THE CYCLONE. VERY STRONG LOW/MID LEVELFRONTOGENESIS WILL OCCUR WITHIN THE TROWAL AND COINCIDENT WITH THERAPIDLY STRENGTHENING CYCLONE WILL PROMOTE STRONG VERTICALCIRCULATION. GUIDANCE ALSO SUGGESTS WEAKLY STABLE TO UNSTABLECONDITIONS ALOFT WITHIN THIS TROWAL WITH NEGATIVE EPV AND STEEPMID-HIGH LEVEL LAPSE RATES...WHICH GIVEN THE STRONG FRONTOGENESISWOULD TEND TO FAVOR A NARROWER BUT INTENSE PRECIPITATION BAND.GFS/WRF-NAM BOTH INDICATE THE PRESENCE OF SOME WEAK UPRIGHTINSTABILITY WHICH GIVEN THE FORCING COULD ALLOW FOR UPRIGHTCONVECTION WITHIN THE DEFO BAND AND POSSIBLY A COUPLE LIGHTNINGSTRIKES.WHILE GUIDANCE IS IN PRETTY GOOD AGREEMENT ON THE ABOVE...THERE AREA COUPLE OF KEY AREAS OF LINGERING UNCERTAINTY. FIRST...MODELBOUNDARY LAYER THERMAL PROFILES ARE FORECAST TO BE QUITE MARGINALFOR SNOW AND EVEN MORE MARGINAL FOR ACCUMULATING SNOW. DESPITE THEMARGINAL THERMAL PROFILES...AM FAIRLY CONFIDENT THAT DYNAMIC COOLINGWITHIN THE DEFO BAND WILL LIKELY EASILY COOL THE BOUNDARY LAYERSUFFICIENTLY TO SUPPORT ACCUMULATING SNOW...PARTICULARLY WHERE THEHEAVIEST PRECIP OCCURS. THE 02/07/13 SYSTEM IS A PRIME EXAMPLE OF ACASE OF VERY STRONG DYNAMIC COOLING THAT WAS VERY POORLY HANDLED BYTHE MODELS AND RESULTED IN NEARLY 10 INCHES OF SNOW WHERE MODELSGUIDANCE FORECAST SFC TEMPS IN THE MID TO UPPER 30S.THE BIGGER UNCERTAINTY AND WHAT IS KEEPING ME FROM JUMPING OUT WITHA WINTER STORM WATCH AT THIS TIME IS THE TRACK DIFFERENCES IN THEMODELS. WHILE THEY ARE NOT HUGE AND NOT SURPRISING GIVEN THE RAPIDLYDEEPENING NATURE OF THE SYSTEM...THEY ARE SUBSTANTIAL ENOUGH TO MAKEIT TOUGH TO PINPOINT THE PORTION OF OUR CWA MOST AT RISK. GIVENCOMBINATION OF STRONG FRONTOGENESIS...INSTABILITY...AND MARGINALTHERMAL PROFILES IT SEEMS LIKELY THE AREAL EXTENT OF HEAVY SNOWWOULD NOT BE LARGE WITH POTENTIALLY SHARP CUT OFF ON BOTH THEWESTERN AND EASTERN FLANKS OF THE SNOW BAND...SIMILAR TO WHAT WASSEEN IN THE 12/01/2006 SYSTEM WHICH IS ONE OF THE STRONGEST ANALOGSFOR THIS SYSTEM AND PRODUCED LOCALLY OVER A FOOT OF SNOW.THE CURRENT SNOWFALL FORECAST MAP WAS CREATED BLENDING VARYINGMODEL TRACK SOLUTIONS TOGETHER WHICH YIELD SNOWFALL AMOUNTS THATWILL LIKELY BE TOO LOW WHERE THE HEAVIEST SNOW FALLS AND TOO HIGHOUTSIDE OF THAT BAND...BUT LIKELY THE BEST COMPROMISE THAT CAN BEDONE FROM THIS DISTANCE GIVEN WHAT LOOKS TO BE A MESOSCALE HEAVYSNOW THAT WILL SET UP. WHERE THE HEAVY SNOW BAND SETS UP...THINK ITIS PRETTY LIKELY THAT VSBYS OF 1/4SM OR LESS WITH HEAVY WET SNOW ARELIKELY WITH SNOWFALL RATES >/= 2 INCHES PER HOUR POSSIBLE. THE PEAKINTENSITY OF THE SNOW LOOKS TO COINCIDE WITH THE DAYTIME HOURS WHENMANY PEOPLE WILL LIKELY BE TRAVELING...SO ASSUMING THE BAND SETS UPAS EXPECTED...IT COULD MAKE TRAVEL EXTREMELY DIFFICULT TOMORROWAFTERNOON. SOME MODELS ARE AS FAR WEST AS NW IL INTO RFD (PARALLELGFS AND WRF-NMM) RANGING TO AS FAR EAST AS NORTHWEST INDIANA (00ZECMWF). WOULD TEND TO FAVOR THE MORE WESTERN SOLUTIONS AS RAPIDLYDEEPENING CYCLONES TYPICALLY TEND TO END UP FARTHER WEST THANPROGGED WHICH COULD FAVOR CHICAGO AREA OR POINTS JUST WEST FOR THEHEAVY SNOW THREAT. BUT WITH A STILL RELATIVELY LARGE SPREAD IN TRACKSOLUTIONS WOULD BE DIFFICULT TO PIN POINT A SPECIFIC AREA FOR AWINTER STORM WATCH WHEN IN REALITY THE HEAVY (6"+) SNOW AMOUNTSCOULD BE CONFINED TO INTERNALLY...WITH NEIGHBORING WFOS...AND WPC HAVE OPTED TO JUST HITTHE THREAT HARD IN UPDATED SPS AND HOPEFULLY MORNING MODEL RUNS WILLNARROW DOWN THE THREAT AREA ENOUGH TO ALLOW HEADLINES TO BE ISSUEDBY MIDDAY.IZZI IZZI pretty confident on the threat of potential Thundersnow! There you go Tim, you can at least use only one of your 2 favorite words for this storm...Thundersnow. Hopefully the "B" word will be used at least once this season. Haha. Anyway, kinda smart of him to use past experience and mention last winter's storm that dumped more snow than models progged. Should be interesting to see what the HRRR models shows later tonight. 1 Quote Link to comment Share on other sites More sharing options...
Yerf Posted December 23, 2014 Report Share Posted December 23, 2014 Just going to post that Tom! Looking good Quote Link to comment Share on other sites More sharing options...
Tony Posted December 23, 2014 Report Share Posted December 23, 2014 Nam is usually within its range under 24hrs out and I like to compare it to the other hi-res models(just for accuracy sake)otherwise I think it is a terrible model. The 12z has backed off a bit on its qpf, but not by much. I can see where the very heavy banding does setup of getting rates of up to or greater than 2" per hour as LOT has mentioned. Heavy cement pasted snow will look like a snow globe once it is all done. As far as totals, the heavy rates of snowfall will easily overcome the warm ground issues and depending on how fast the turnover is, some areas could see 10"+ out of this. Of course this is just my thinking and I could be way off but the dynamics of this storm really look impressive and I could easily see it take off. GOM moisture will be plentiful and looking quite impressive. Looking forward to the hi-res models as the day progresses. Quote Link to comment Share on other sites More sharing options...
Money Posted December 23, 2014 Report Share Posted December 23, 2014 RAP at HR 18 has the low down to 996 already while 12z NAM at HR 18 had it the low at 1001. Stuff to watch going forward Quote Link to comment Share on other sites More sharing options...
WildWisconsinWeather Posted December 23, 2014 Report Share Posted December 23, 2014 I think the 4km NAM will be good for east but bad for wisconsin people You have an obsession with bashing Wisconsin, I can tell already. Quote Link to comment Share on other sites More sharing options...
Tony Posted December 23, 2014 Report Share Posted December 23, 2014 You can see the moisture transport from the tropics feeding into the storm as well as the gulf. 1 Quote Link to comment Share on other sites More sharing options...
Tony Posted December 23, 2014 Report Share Posted December 23, 2014 RAP at HR 18 has the low down to 996 already while 12z NAM at HR 18 had it the low at 1001. Stuff to watch going forward Good stuff. Will be interesting to see this play out during the day Quote Link to comment Share on other sites More sharing options...
WildWisconsinWeather Posted December 23, 2014 Report Share Posted December 23, 2014 RAP at HR 18 has the low down to 996 already while 12z NAM at HR 18 had it the low at 1001. Stuff to watch going forward If the RAP is onto something, I would think that would mean an earlier northward turn. Quote Link to comment Share on other sites More sharing options...
Tony Posted December 23, 2014 Report Share Posted December 23, 2014 Hi-res 12z Nam nails NE IL... 1 Quote Link to comment Share on other sites More sharing options...
BigDizBliz420 Posted December 23, 2014 Report Share Posted December 23, 2014 Hi-res 12z Nam nails NE IL... Do u think that is all snow? It looks cold enough... Quote Link to comment Share on other sites More sharing options...
Tom Posted December 23, 2014 Author Report Share Posted December 23, 2014 12z NAM/WRF 4-km... 2 Quote Link to comment Share on other sites More sharing options...
Tony Posted December 23, 2014 Report Share Posted December 23, 2014 Do u think that is all snow? It looks cold enough...See Tom's posted map above^ Quote Link to comment Share on other sites More sharing options...
Money Posted December 23, 2014 Report Share Posted December 23, 2014 GFS gets it down to 998 at hr 18. 3 mb stronger than nam and 1 mb weaker than RAP Quote Link to comment Share on other sites More sharing options...
WildWisconsinWeather Posted December 23, 2014 Report Share Posted December 23, 2014 GFS gets it down to 998 at hr 18. 3 mb stronger than nam and 1 mb weaker than RAP Does it look like it will stay in place or trend NW? Quote Link to comment Share on other sites More sharing options...
Money Posted December 23, 2014 Report Share Posted December 23, 2014 993 in E. IN at HR 27. Moves more NE rather than N No one sees snow this run really. Temps look too warm in the Chicago area. Quote Link to comment Share on other sites More sharing options...
Money Posted December 23, 2014 Report Share Posted December 23, 2014 Maybe 1-2 inches from west of chicago up to milwaukee .4-.5 qpf for you WWW, and .5 or so for Chicago. Quote Link to comment Share on other sites More sharing options...
Tony Posted December 23, 2014 Report Share Posted December 23, 2014 I wish this was more of a "share the wealth" kind of storm so everyone could cash in. Maybe once we get into January we could get a few of those and hope to have an abundance of cold air around to support snow! Quote Link to comment Share on other sites More sharing options...
WildWisconsinWeather Posted December 23, 2014 Report Share Posted December 23, 2014 993 in E. IN at HR 27. Moves more NE rather than N No one sees snow this run really. Temps look too warm in the Chicago area. If trends hold, looks like the GFS and its ensembles failed a bit as well. As of yesterday's 18z suite, almost all of the ensembles were wrapped up storms tracking into SW Lower Michigan or over LM. Quote Link to comment Share on other sites More sharing options...
BigDizBliz420 Posted December 23, 2014 Report Share Posted December 23, 2014 GFS looks great, dynamic cooling would lead to snow i think Quote Link to comment Share on other sites More sharing options...
WildWisconsinWeather Posted December 23, 2014 Report Share Posted December 23, 2014 Maybe 1-2 inches from west of chicago up to milwaukee .4-.5 qpf for you WWW, and .5 or so for Chicago. Well, I'll take a White Christmas, however we get it. Quote Link to comment Share on other sites More sharing options...
Money Posted December 23, 2014 Report Share Posted December 23, 2014 Looks a lot more generous on the QPF side compared to previous runs. Even up here, it's .2-.3 qpf Quote Link to comment Share on other sites More sharing options...
Scott26 Posted December 23, 2014 Report Share Posted December 23, 2014 993 in E. IN at HR 27. Moves more NE rather than N No one sees snow this run really. Temps look too warm in the Chicago area. GFS clearly can't handle mesoscale factors like dynamic cooling. That is why looking at global models at this point is pretty pointless. 2 Quote Link to comment Share on other sites More sharing options...
Money Posted December 23, 2014 Report Share Posted December 23, 2014 If trends hold, looks like the GFS and its ensembles failed a bit as well. As of yesterday's 18z suite, almost all of the ensembles were wrapped up storms tracking into SW Lower Michigan or over LM. http://www.tropicaltidbits.com/analysis/models/gfs/2014122312/gfs_mslp_pcpn_frzn_us_5.png http://www.tropicaltidbits.com/analysis/models/gfs/2014122312/gfs_mslp_pcpn_frzn_us_6.png Quote Link to comment Share on other sites More sharing options...
Tony Posted December 23, 2014 Report Share Posted December 23, 2014 GFS looks great, dynamic cooling would lead to snow i thinkI don't think "will it snow" is an issue at this point just how quick will it turnover and how intense the defo band will be. Quote Link to comment Share on other sites More sharing options...
WildWisconsinWeather Posted December 23, 2014 Report Share Posted December 23, 2014 http://www.tropicaltidbits.com/analysis/models/gfs/2014122312/gfs_mslp_pcpn_frzn_us_5.png http://www.tropicaltidbits.com/analysis/models/gfs/2014122312/gfs_mslp_pcpn_frzn_us_6.png Most of the Ensembles were west of the OP. Quote Link to comment Share on other sites More sharing options...
WildWisconsinWeather Posted December 23, 2014 Report Share Posted December 23, 2014 http://mp1.met.psu.edu/~fxg1/ENSPRSNE_18z/f48.gif Quote Link to comment Share on other sites More sharing options...
Maxim Posted December 23, 2014 Report Share Posted December 23, 2014 12/1/06 redux? 1 Quote Link to comment Share on other sites More sharing options...
Tony Posted December 23, 2014 Report Share Posted December 23, 2014 12/1/06 redux?Can you refresh my memory please. Quote Link to comment Share on other sites More sharing options...
Money Posted December 23, 2014 Report Share Posted December 23, 2014 http://www.tropicaltidbits.com/analysis/models/gfsp/2014122312/gfsp_mslp_pcpn_frzn_us_6.png Quote Link to comment Share on other sites More sharing options...
Money Posted December 23, 2014 Report Share Posted December 23, 2014 15z RAP gets it down to 995 at HR 18 and a bit farther west than nam/gfs at that time. Quote Link to comment Share on other sites More sharing options...
WildWisconsinWeather Posted December 23, 2014 Report Share Posted December 23, 2014 15z RAP gets it down to 995 at HR 18 and a bit farther west than nam/gfs at that time. I hope the RAP is onto something, not on something lol. Quote Link to comment Share on other sites More sharing options...
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