phil882 Posted February 25, 2015 Share Posted February 25, 2015 Our local media outlets are showing rain from about 5p-10p on their models! That would greatly reduce snow total, no? Depends on how heavy the precip is initially. The rates with this event will be pretty significant which would have the effect to quickly bring the low-level profile to isothermal as melting snowflakes cool the column as they dynamically cool air while they melt. The fact that the majority of this event is occurring at night is good, because we won't be competing against solar insolation near the boundary layer. Thus, the melting snow cooling the column should win out overall. The boundary layer here is too warm at 7pm tonight at KGSP. After a couple more hours of heavy precip, we are below freezing throughout the column by 10pm. Link to comment Share on other sites More sharing options...
jburns Posted February 25, 2015 Share Posted February 25, 2015 It doesn't, BUT heavy wet snow does bear greatly on tree limbs. There is only so much snow that can accumulate on power lines but ice would just keep on and on. Tony I've seen power lines made as big around as my upper arm with snow. If the snow is wet enough and there is little wind, it can bring them down all on its own. Link to comment Share on other sites More sharing options...
RevDodd Posted February 25, 2015 Share Posted February 25, 2015 Now that the RAP has been at least partiially vindicated: Went back 6 hours on the precip totals (never mind the insane snow map). what struck me was not just that the RAP amped QPF totals, but how it was doing so. I can't say I'm buying into the totals, but it looks like the RAP is figuring heavy precip rates are helping with mid-level temps and shifting accordingly. If the precip rates are valid, the RAP is valid. If the numbers are heavy the snow levels will collapse in areas like ours. It will be fun to see how it evolves into the evening. Link to comment Share on other sites More sharing options...
griteater Posted February 25, 2015 Share Posted February 25, 2015 Euro tracks the 850 low roughly from Macon to Florence to Kill Devil Hills...so, not bad for GSP to CLT to RDU...really close call for those locations on sleet mixing in. Verbatim, 850 is fine, but could be sneaky warm layer above it...on the flip side, you could have intense lift (cooling mechanism) to counteract it. Link to comment Share on other sites More sharing options...
nchighcountrywx Posted February 25, 2015 Share Posted February 25, 2015 Latest official map from NWS GSP as of 1:17pm Link to comment Share on other sites More sharing options...
packfan98 Posted February 25, 2015 Share Posted February 25, 2015 From Ellinwood in the MA forum: Link to comment Share on other sites More sharing options...
slickwillbo Posted February 25, 2015 Share Posted February 25, 2015 The initial finger of precip was modeled to be 30 miles or so North of Atlanta, but it ended up centering right on the Atlanta area...interesting for sure. It's coming down as sleet here in Decatur. Link to comment Share on other sites More sharing options...
tonysc Posted February 25, 2015 Share Posted February 25, 2015 It doesn't, BUT heavy wet snow does bear greatly on tree limbs. There is only so much snow that can accumulate on power lines but ice would just keep on and on. Tree limbs are a different story. Much more snow can accumulate on tree limbs than on power lines depending on how large they are. And pine trees especially are very easily snapped under more weight because pines are a soft wood. The South is full of pine trees. You are right about ice being much more conducive to there being power outages, but I've never heard of having a big snowstorm here in the Upstate of SC where there were NO power outages. There will be some if we get major snow but they will be so much less than in ice storms that, unless YOUR power goes off, you may not even realize there were any. But listen to your local news stations if you get heavy snow and I would bet you that you will hear of power outages. Tony Also I did forget to mention. Yes there could be big snow with NO power outages and to correct myself I've seen some. But They were talking about "heavy wet" snow. A heavy dry snow is much lighter and fluffier that wet snow. Wet snow is much heavier. That's why they say that 6 inches of wet snow is equal to 20 inches of dry snow. That's not always exactly that 6 to 20 though because it depends on the water content of the wet snow, but in any case you get much higher snowfall totals form the same liquid equivalent of dry snow than wet snow. Link to comment Share on other sites More sharing options...
KChuck Posted February 25, 2015 Share Posted February 25, 2015 Checked out this lightning link and am wondering how much energy the convection shown could rob from the storm and how it might affect us in the big picture. Also noticing a lot of open areas in the national precipitation radar that makes me think those wondering earlier about the dry slotting might have something to worry about. Thoughts??? Link to comment Share on other sites More sharing options...
strongwxnc Posted February 25, 2015 Share Posted February 25, 2015 http://www.americanwx.com/bb/index.php/topic/45823-feb-25-26-discussionpbp/?p=3449022 Checked out this lightning link and am wondering how much energy the convection shown could rob from the storm and how it might affect us in the big picture. Also noticing a lot of open areas in the national precipitation radar that makes me think those wondering earlier about the dry slotting might have something to worry about. Thoughts??? Link to comment Share on other sites More sharing options...
tonysc Posted February 25, 2015 Share Posted February 25, 2015 I've seen power lines made as big around as my upper arm with snow. If the snow is wet enough and there is little wind, it can bring them down all on its own. But snow is MUCH lighter, even wet snow, than ice is. It's just that simple. Link to comment Share on other sites More sharing options...
packfan98 Posted February 25, 2015 Share Posted February 25, 2015 DT Link to comment Share on other sites More sharing options...
franklin NCwx Posted February 25, 2015 Share Posted February 25, 2015 Latest official map from NWS GSP as of 1:17pm does anyone know what these gsp maps are based off of? They seem to Change every three hours and not reflect their discussions. Link to comment Share on other sites More sharing options...
Shawn Posted February 25, 2015 Share Posted February 25, 2015 This makes no sense to me as it won't back off down this way: Link to comment Share on other sites More sharing options...
a5ehren Posted February 25, 2015 Share Posted February 25, 2015 Light sleet here in Dunwoody now. PWS says 37F. Link to comment Share on other sites More sharing options...
strongwxnc Posted February 25, 2015 Share Posted February 25, 2015 Here was the only lanauge that stated anything about changes. This was at 12:40 pm NEAR TERM /THROUGH TONIGHT/...AS OF 1240 PM...MADE SOME MINOR ADJUSTMENTS TO TEMP TRENDS. does anyone know what these gsp maps are based off of? They seem to Change every three hours and not reflect their discussions. Link to comment Share on other sites More sharing options...
KChuck Posted February 25, 2015 Share Posted February 25, 2015 http://www.americanwx.com/bb/index.php/topic/45823-feb-25-26-discussionpbp/?p=3449022 Thanks! Late comer to board today and not take time to read thru all discussions due to taking care of friend in hospital. Link to comment Share on other sites More sharing options...
stlirish Posted February 25, 2015 Share Posted February 25, 2015 DT He's really low for N. Ga. Not sure I'm buying that Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
MichaelJ Posted February 25, 2015 Share Posted February 25, 2015 Looks like the storm is continuing to deepen on the models and will be well below the early strength numbers we were seeing earlier. If that continues to happen, this will probably continue some NW trend and increase precip totals but also present some mixing issues for some of the board members. Who exactly would be affected is impossible to say until we see the actual, not projected, track and strength. Hopefully is will be a non issue for most Link to comment Share on other sites More sharing options...
Carvers Gap Posted February 25, 2015 Share Posted February 25, 2015 Ah OK just saw all the NW talk with some negativity and assumed some were taking it as gospel. I don't see it as a NW trend at all...maybe a tad, but not much. Looks like the precip shield has expanded. That is a big difference. NC is money for this one. Good luck to you all! Link to comment Share on other sites More sharing options...
burgertime Posted February 25, 2015 Share Posted February 25, 2015 17z HRRR gives CLT 1.29 of QPF Link to comment Share on other sites More sharing options...
CarlHill Posted February 25, 2015 Share Posted February 25, 2015 Depends on how heavy the precip is initially. The rates with this event will be pretty significant which would have the effect to quickly bring the low-level profile to isothermal as melting snowflakes cool the column as they dynamically cool air while they melt. The fact that the majority of this event is occurring at night is good, because we won't be competing against solar insolation near the boundary layer. Thus, the melting snow cooling the column should win out overall. The boundary layer here is too warm at 7pm tonight at KGSP. After a couple more hours of heavy precip, we are below freezing throughout the column by 10pm. So, are you saying rain from 7pm to 10pm? That would kill our totals!!! Link to comment Share on other sites More sharing options...
hickory Posted February 25, 2015 Share Posted February 25, 2015 Thanks for all the post about wet snow vs dry snow. I would love one day for someone to do some research about this with some actually numbers and history. This does seem to be a heavy wet snow for a number of locations throughout the south Link to comment Share on other sites More sharing options...
HKY_WX Posted February 25, 2015 Share Posted February 25, 2015 This makes no sense to me as it won't back off down this way: Dynamics man. Not out of the ordinary for an upper low to produce rapid enough rates to overwhelm the column. It's interesting this particular 500mb low is causing this though, considering it is opening up over the tn valley. Usually these kinda totals only happen under closed lows. Link to comment Share on other sites More sharing options...
tonysc Posted February 25, 2015 Share Posted February 25, 2015 I've seen power lines made as big around as my upper arm with snow. If the snow is wet enough and there is little wind, it can bring them down all on its own. you are right about that, but he was specifically asking about the difference of ice accumulations and snow accumulations. I'd be willing to bet you money that there will not be anything close to the power outages from heavy snowstorms than from heavy ice storms. I've seen many, many of both in my lifetime and that's just the way it is, but it's not really that hard to figure out. It's just physics. Link to comment Share on other sites More sharing options...
burrel2 Posted February 25, 2015 Share Posted February 25, 2015 Lord have mercy... Looks like thundersnow for the upstate tonight!! Link to comment Share on other sites More sharing options...
franklin NCwx Posted February 25, 2015 Share Posted February 25, 2015 Here was the only lanauge that stated anything about changes. This was at 12:40 pm NEAR TERM /THROUGH TONIGHT/... AS OF 1240 PM...MADE SOME MINOR ADJUSTMENTS TO TEMP TRENDS. anybody in nc and west of char, has no temp issues to worry about and qpf has gone up on every piece of guidance except the gfs. I mean, they had a good forecast yesterday afternoon and discussion. Why change that now? Everything still looks the same if not better for a couple more inches of snow. Link to comment Share on other sites More sharing options...
JQPublic Posted February 25, 2015 Share Posted February 25, 2015 I think the main reasons why we may experience a cut down on totals here is that snow will be falling while 1. temps are above freezing initially 2. Some areas may push 50 today around the triangle so ground temps will be warm. Link to comment Share on other sites More sharing options...
phil882 Posted February 25, 2015 Share Posted February 25, 2015 You guys might also be interested in these new maps not on my website yet (and as far as I know not available anywhere else). Here are frontogenesis plots centered over the southeast for this event from the HRRR for 925/850/700 and Reflectivity as well. http://www.atmos.albany.edu/student/ppapin/lb13_img/hrrr/hrrr_ncep_fgen_all_gsp.php The frontogenetical forcing initially might be very strong over locations that will start up above freezing, suggestive that the start of the precipitation will be rather fast with a possibility for an intense mesoscale band. Something to watch. Link to comment Share on other sites More sharing options...
skbl17 Posted February 25, 2015 Share Posted February 25, 2015 This makes no sense to me as it won't back off down this way: I don't know if my glasses are on wrong or what, but I think the RAP is trying to bring the snow shield a tad bit south. CAE is looking a tad bit better on the RAP, and even ATL inside the perimeter is up to ~2-2.5". Heck, even AGS gets a trace, while they had absolutely nothing on previous runs. Maybe my glasses are on backwards. Link to comment Share on other sites More sharing options...
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