gosaints Posted January 29, 2013 Share Posted January 29, 2013 Based on current radar trends, I was actually concerned the models would shift back NW. Much of SC and SW Wisconsin are getting heavy rain, and it looks like it spreading further N and W than the NAM and GFS were depicting. To me that seemed to signal we might see a N and W adjustment yet. May not be the case though. Was noticing the same thing when comparing radar to what the NAM shows. Who the h knows at this point Link to comment Share on other sites More sharing options...
turtlehurricane Posted January 29, 2013 Share Posted January 29, 2013 12z GFS giving Madison about 0.56" of rain and 0.75" liquid equivalent snow. Ratios start out below 10:1 but increase to 20:1 for a good chunk of the storm, the more advanced BUFKIT snow ratio algorithms give storm totals between 8-11". NAM is much wetter, shows 1" of rain followed by 0.7" liquid as snow. Fairly good agreement between GFS and NAM on the liquid equivalent snow at least. This went from a little snow after a deluge to a full on winter storm within a day, just goes to show modeling has a long way to go. Link to comment Share on other sites More sharing options...
Luftfeuchtigkeit Posted January 29, 2013 Share Posted January 29, 2013 Based on current radar trends, I was actually concerned the models would shift back NW. Much of SC and SW Wisconsin are getting heavy rain, and it looks like it spreading further N and W than the NAM and GFS were depicting. To me that seemed to signal we might see a N and W adjustment yet. May not be the case though. Yeah, I was wondering the same thing. 12Z NAM did a better job depicting the heavy rain this afternoon pushing north into SW/SC Wisconsin. 18Z NAM barely shows any rain this afternoon in my area yet we may get 1/2 an inch or more. I'm wondering if the 18Z NAM may have pushed everything too far S/E and need a N/W adjustment back closer to the 12Z position. Link to comment Share on other sites More sharing options...
Chicago WX Posted January 29, 2013 Share Posted January 29, 2013 Probably best to remember exact model solutions aren't the final outcome. Wouldn't toss my chances away anywhere in the ARX CWA. Link to comment Share on other sites More sharing options...
wisconsinwx Posted January 29, 2013 Author Share Posted January 29, 2013 12z GFS giving Madison about 0.56" of rain and 0.75" liquid equivalent snow. Ratios start out below 10:1 but increase to 20:1 for a good chunk of the storm, the more advanced BUFKIT snow ratio algorithms give storm totals between 8-11". NAM is much wetter, shows 1" of rain followed by 0.7" liquid as snow. Fairly good agreement between GFS and NAM on the liquid equivalent snow at least. This went from a little snow after a deluge to a full on winter storm within a day, just goes to show modeling has a long way to go. Those snow:liquid ratios are quite high. As for the 18z NAM, it probably did initiate incorrectly, hate to say. Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 29, 2013 Share Posted January 29, 2013 weenie band for chicago...very odd looking Link to comment Share on other sites More sharing options...
Chicago WX Posted January 29, 2013 Share Posted January 29, 2013 weenie band for chicago...very odd looking NMM-like. It kicked up a little bow/or line as the front swept through here. Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 29, 2013 Share Posted January 29, 2013 NMM-like. It kicked up a little bow/or line as the front swept through here. true, it does look similar. Sidenote, as rare as rain to snow events are...2" of rain to snow events must be non-existent. Link to comment Share on other sites More sharing options...
Geos Posted January 29, 2013 Share Posted January 29, 2013 weenie band for chicago...very odd looking Convection wrap around. Sometimes those can deliver. This will be a now cast storm I'm thinking. Link to comment Share on other sites More sharing options...
turtlehurricane Posted January 29, 2013 Share Posted January 29, 2013 Those snow:liquid ratios are quite high. As for the 18z NAM, it probably did initiate incorrectly, hate to say. The ratios actually get as high as 30:1 and spend a significant amount of time around 25:1, but I don't believe that so I rounded down to 20:1. Overall I think we'll be around 12:1 or 15:1 when you consider the lower ratio snows at the beginning, if the 12z GFS is actually right. And I was looking at the 12z NAM fwiw. Still wary to totally latch onto this solution since things have changed so much in the past day, but usually when models trend at the last minute like this they trend towards the correct solution, since they're probably seeing something that was previously unsampled over the open North Pacific. Link to comment Share on other sites More sharing options...
Chicago WX Posted January 29, 2013 Share Posted January 29, 2013 true, it does look similar. Sidenote, as rare as rain to snow events are...2" of rain to snow events must be non-existent. December 1929 in the LAF. Well, close enough. Hoosier knows the details. 15z SREF snow probs moved east again. 75% or more chance of 1"+ at ORD. 95% for Geos! Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 29, 2013 Share Posted January 29, 2013 ! Link to comment Share on other sites More sharing options...
Hoosier Posted January 29, 2013 Share Posted January 29, 2013 December 1929 in the LAF. Well, close enough. Hoosier knows the details. 15z SREF snow probs moved east again. 75% or more chance of 1"+ at ORD. 95% for Geos! That might've been like a 1 in 300 year storm for LAF. Mind boggling that you can get that much rain and snow. Link to comment Share on other sites More sharing options...
RCNYILWX Posted January 29, 2013 Share Posted January 29, 2013 same as yesterday, over (mke) under (ord) How about over/under the 0.3" from 12/30-12/21 for ORD? I'll take the over. Link to comment Share on other sites More sharing options...
Luftfeuchtigkeit Posted January 29, 2013 Share Posted January 29, 2013 The ratios actually get as high as 30:1 and spend a significant amount of time around 25:1, but I don't believe that so I rounded down to 20:1. Overall I think we'll be around 12:1 or 15:1 when you consider the lower ratio snows at the beginning, if the 12z GFS is actually right. And I was looking at the 12z NAM fwiw. Still wary to totally latch onto this solution since things have changed so much in the past day, but usually when models trend at the last minute like this they trend towards the correct solution, since they're probably seeing something that was previously unsampled over the open North Pacific. Turtle, could you comment on the effect wind has on snow ratios? I've heard people talk of strong winds "breaking up flakes" or something like that which would reduce the ratio. This storm won't have especially strong winds in the deformation area though so hopefully it wouldn't be a big factor. Also I know wind makes it hard to measure with drifting which could reduce the measured amounts and ratios a bit. Thanks! Link to comment Share on other sites More sharing options...
Justin Posted January 29, 2013 Share Posted January 29, 2013 Starting to like our chances at making 5"+ here which would be our biggest snowfall since the ghd blizzard in 2011. Link to comment Share on other sites More sharing options...
Chicago WX Posted January 29, 2013 Share Posted January 29, 2013 ! !! Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 29, 2013 Share Posted January 29, 2013 trends are undeniable...what a mess Link to comment Share on other sites More sharing options...
Chicago WX Posted January 29, 2013 Share Posted January 29, 2013 That might've been like a 1 in 300 year storm for LAF. Mind boggling that you can get that much rain and snow. Yeah, we'll never see that in our lifetimes. Big clap of thunder just now. This April rocks. Link to comment Share on other sites More sharing options...
gosaints Posted January 29, 2013 Share Posted January 29, 2013 Nam and sref locked in on this thing Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 29, 2013 Share Posted January 29, 2013 just peaked at the quick extraction for the last couple NAM runs...both showed TSSN at ORD Link to comment Share on other sites More sharing options...
BowMeHunter Posted January 29, 2013 Share Posted January 29, 2013 Anybody look at that FIM model lately? Link to comment Share on other sites More sharing options...
wisconsinwx Posted January 29, 2013 Author Share Posted January 29, 2013 Anybody look at that FIM model lately? The 0z FIM gave us just 0.01-0.1" QPF snow (as it has a map of snow equivalent precip), but that is the most recent run I have seen. Link to comment Share on other sites More sharing options...
turtlehurricane Posted January 29, 2013 Share Posted January 29, 2013 Turtle, could you comment on the effect wind has on snow ratios? I've heard people talk of strong winds "breaking up flakes" or something like that which would reduce the ratio. This storm won't have especially strong winds in the deformation area though so hopefully it wouldn't be a big factor. Also I know wind makes it hard to measure with drifting which could reduce the measured amounts and ratios a bit. Thanks! I think the biggest problem with wind and ratios is that it's hard to get accurate measurements of snowfall as it becomes more windy. Higher wind causes more flake collisions and therefore smaller flakes, but the mass of actual snow doesn't change from this. In fact more snow growth may occur since the fragments of collided snow flakes act as ice nuclei. It is forecast to be decently windy in Madison during the snow btw, winds sustained around 20 mph and gusting to 30-40 mph. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 29, 2013 Share Posted January 29, 2013 trends are undeniable...what a mess what is hilarious is that we were saying this yesterday about the NW trend. Link to comment Share on other sites More sharing options...
wisconsinwx Posted January 29, 2013 Author Share Posted January 29, 2013 what is hilarious is that we were saying this yesterday about the NW trend. Well with the NAM continually jumping NW and the GFS Ensembles doing the same, it seemed right at the time. Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 29, 2013 Share Posted January 29, 2013 what is hilarious is that we were saying this yesterday about the NW trend. heavy rain axis did trend NW...500 vort shenanigans were unforeseen. My calls still look good. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 29, 2013 Share Posted January 29, 2013 Interesting stat from Skilling.. "Found 19 of 21 of the 60-deg spells in Januarys here were followed by measurable snow (at least 0.1”)—and that 12 of them saw 1”+ totals; 8 were followed by 4”+ tallies; 4 had 6” or more and just one---1967—was followed by 23”" Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 29, 2013 Share Posted January 29, 2013 Interesting stat from Skilling.. "Found 19 of 21 of the 60-deg spells in Januarys here were followed by measurable snow (at least 0.1”)—and that 12 of them saw 1”+ totals; 8 were followed by 4”+ tallies; 4 had 6” or more and just one---1967—was followed by 23”" followed meaning within 24 hours? Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 29, 2013 Share Posted January 29, 2013 Think it was Hoosier mentioning DGZ depth. SREF shows it nicely. Link to comment Share on other sites More sharing options...
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