clskinsfan Posted January 13, 2017 Share Posted January 13, 2017 17 minutes ago, WinterWxLuvr said: Text data for 18z NAM for KOKV shows a 0.2 reading at 800 for Winchester. That won't cut it if you're looking for sleet or freezing rain. All other levels were below freezing. Sorry brother. Carry on without me. Link to comment Share on other sites More sharing options...
yoda Posted January 13, 2017 Share Posted January 13, 2017 2 minutes ago, WinterWxLuvr said: That would be great. Thanks 18z NAM at 39 18z NAM at 42 18z NAM at 45 Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 13, 2017 Share Posted January 13, 2017 1 minute ago, clskinsfan said: Thanks Yoda! Just ignore me the rest of the night. I clearly dont know what the hell I'm talking about. No, that's not correct. You do. My stance is that we will have a snow window of a few hours. You're correct. We are going to change at some point. Link to comment Share on other sites More sharing options...
kurtstack Posted January 13, 2017 Share Posted January 13, 2017 this isnt the typical type of overunning mix event in that we dont have a big spun up low that drives warm layer north at light speed - we have very light winds and if we set up initially with a good column it will likely take a while for any changeover.Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 13, 2017 Share Posted January 13, 2017 1 minute ago, clskinsfan said: Sorry brother. Carry on without me. Not gonna happen brother. You stay right here. I need company. Eastcoast jumped about 6 weeks ago. Link to comment Share on other sites More sharing options...
yoda Posted January 13, 2017 Share Posted January 13, 2017 3 minutes ago, clskinsfan said: Thanks Yoda! Just ignore me the rest of the night. I clearly dont know what the hell I'm talking about. I would never do that... you post excellent stuff and you always know what you are talking about... I think we just crossed lines... I apologize if I stepped too far Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 13, 2017 Share Posted January 13, 2017 1 minute ago, yoda said: 18z NAM at 39 18z NAM at 42 18z NAM at 45 This is what I was thinking. The precip cools the upper levels from 39 to 42. Looks like possible sleet to probable snow. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 13, 2017 Share Posted January 13, 2017 2 minutes ago, kurtstack said: this isnt the typical type of overunning mix event in that we dont have a big spun up low that drives warm layer north at light speed - we have very light winds and if we set up initially with a good column it will likely take a while for any changeover. Sent from my iPhone using Tapatalk This is a great point! Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 13, 2017 Share Posted January 13, 2017 So, IMO, we are back to my old fall back position. Will we get good precip? Link to comment Share on other sites More sharing options...
yoda Posted January 13, 2017 Share Posted January 13, 2017 Just now, WinterWxLuvr said: This is what I was thinking. The precip cools the upper levels from 39 to 42. Looks like possible sleet to probable snow. I apologize if I stepped over the line... it wasn't my intention to Link to comment Share on other sites More sharing options...
WVclimo Posted January 13, 2017 Share Posted January 13, 2017 OTOH... Not sure what algorithm is being used here, but these maps would support clskinsfan's original contention. From the 18Z GFS: Snow accumulation: Sleet accumulation: Freezing rain: Link to comment Share on other sites More sharing options...
BTRWx Posted January 13, 2017 Share Posted January 13, 2017 3 minutes ago, WinterWxLuvr said: This is a great point! I tried to imply that yesterday, so I'm glad you're emphasizing that. Link to comment Share on other sites More sharing options...
MillvilleWx Posted January 13, 2017 Share Posted January 13, 2017 Looking at the GFS sounding from 18z, the column will be cold enough for snow for the first part of the storm. The layers in question lie between 850-700mb where the temperatures are fairly close to freezing with a smidge above freezing at times, but that would ultimately just affect the composition of the flakes. These certainly will not be aggregates, but I know everyone knows that by now. Hour 42 Hour 45 Notice the temperature profile on the left hand side. At hour 45, there's a better signal for heavier precip, leading to a touch more evaporative cooling allowing the entire profile to go below freezing. The thin white line on the sounding is the forecasted omega and the best forcing looks to be around hour 45 compared to the hour 42 before. Grant it, it's not off the charts by any means, but certainly enough to provide a moderate snow for the District. Hour 48 This is where the model shows a precip change due to the increased warm layer between the 850-700mb region aloft. If the precip is heavy enough, there could easily be snow flakes mixing in with how close the the mid levels are with temps, but I would suspect this is when the best forcing is pushed east and the system is winding down, so makes sense to see the change there. Further north could be a different story and could stay cooler longer, but the difference will not be extreme in this type of event due to strength of the energy and no real formidable area of low pressure. Personally, with the way the winter has gone so far and how close the event is to what the models are currently showing, I could see a slight shift north in the models, especially high res guidance tomorrow. The reasoning for my thinking is just climo and the trends so far all year; slight adjustments north, boundary a little further north at final observation ending up with better axis of precip closer to the MD line. I hope I'm wrong in some ways because I live in Germantown and would love what the GFS and NAM is showing, so I'm keeping my fingers crossed. The best would be for the axis of precip to be more robust and everyone cashes in. We shall see. Been an interesting winter nonetheless. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 13, 2017 Share Posted January 13, 2017 1 minute ago, yoda said: I apologize if I stepped over the line... it wasn't my intention to I don't think anybody crossed any lines. We are all on the same team here. I look at it as we are all just comparing ideas. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 13, 2017 Share Posted January 13, 2017 2 minutes ago, WVclimo said: OTOH... Not sure what algorithm is being used here, but these maps would support clskinsfan's original contention. From the 18Z GFS: Snow accumulation: Sleet accumulation: Freezing rain: Yeah, and I was looking st the rgem snow maps and it shows NONE here. It's going to be so close that any of us could be right. Link to comment Share on other sites More sharing options...
nw baltimore wx Posted January 13, 2017 Share Posted January 13, 2017 1 minute ago, WinterWxLuvr said: I don't think anybody crossed any lines. We are all on the same team here. I look at it as we are all just comparing ideas. Yeah. Quality discussion and no pissy ny brawls. It's good to disagree. Link to comment Share on other sites More sharing options...
BTRWx Posted January 13, 2017 Share Posted January 13, 2017 11 minutes ago, yoda said: 18z NAM at 39 18z NAM at 42 18z NAM at 45 That's Winchester, right? Link to comment Share on other sites More sharing options...
yoda Posted January 13, 2017 Share Posted January 13, 2017 Weird... this map is way different that I used @WVclimo Link to comment Share on other sites More sharing options...
yoda Posted January 13, 2017 Share Posted January 13, 2017 2 minutes ago, BTRWx said: That's Winchester, right? Yes Link to comment Share on other sites More sharing options...
BTRWx Posted January 13, 2017 Share Posted January 13, 2017 Interesting how dry the layer looks just above the surface soon before the column saturates on the NAM. This scenario could help our temperatures fall. Am I correct in saying that this bufkit profile implies evaporative cooling? Link to comment Share on other sites More sharing options...
CAPE Posted January 13, 2017 Share Posted January 13, 2017 Interesting snippet from Mount Holly AFD, and it makes some sense- Precipitation type as has been all winter gets a little more complicated. Typical model bias at this range is for the data to be cold in the mid-levels and too warm at the surface. Overall, these biases lead to higher prospects of ice as we get closer to an event. Link to comment Share on other sites More sharing options...
kurtstack Posted January 13, 2017 Share Posted January 13, 2017 prolonged sleet storms are mighty rare but they do happen and i wouldnt be surprised if some locations turn in 6-7 hours of sleet - which personally i find pretty cool tooSent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
yoda Posted January 13, 2017 Share Posted January 13, 2017 @MillvilleWx great post and thanks for the explanation... very easy to understand Link to comment Share on other sites More sharing options...
WVclimo Posted January 13, 2017 Share Posted January 13, 2017 2 minutes ago, yoda said: Weird... this map is way different that I used @WVclimo I see that also, Yoda. RaleighWX built so much into his model site, you can really play with a lot of things. The maps I posted are in a section entitled Snow and Ice: **Attempt to separate Snow/Sleet/Frz Rain** Link to comment Share on other sites More sharing options...
kurtstack Posted January 13, 2017 Share Posted January 13, 2017 prolonged sleet storms are mighty rare but they do happen and i wouldnt be surprised if some locations turn in 6-7 hours of sleet - which personally i find pretty cool tooSent from my iPhone using Tapatalkand given the density of sleet roads deteriorate quite quickly regardless of the initial road tempSent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
yoda Posted January 13, 2017 Share Posted January 13, 2017 Just now, WVclimo said: I see that also, Yoda. RaleighWX built so much into his model site, you can really play with a lot of things. The maps I posted are in a section entitled Snow and Ice: **Attempt to separate Snow/Sleet/Frz Rain** Ah I see that now... I will take a gander at that for the 00z NAM and 00z GFS Link to comment Share on other sites More sharing options...
MillvilleWx Posted January 13, 2017 Share Posted January 13, 2017 Just now, BTRWx said: Interesting how dry the layer looks just above the surface soon before the column saturates. This scenario could help our temperatures fall. Am I correct in saying that this bufkit profile implies evaporative cooling? Yes, the profile temps should drop as the column saturates. The process is called wet bulbing. You can check that temperature clicking the wet bulb option in the list of overlay options on the left hand side. Link to comment Share on other sites More sharing options...
BTRWx Posted January 13, 2017 Share Posted January 13, 2017 3 minutes ago, MillvilleWx said: Yes, the profile temps should drop as the column saturates. The process is called wet bulbing. You can check that temperature clicking the wet bulb option in the list of overlay options on the left hand side. oops, thanks Link to comment Share on other sites More sharing options...
MillvilleWx Posted January 13, 2017 Share Posted January 13, 2017 6 minutes ago, yoda said: @MillvilleWx great post and thanks for the explanation... very easy to understand Just now, BTRWx said: oops, thanks No problem guys! Link to comment Share on other sites More sharing options...
kurtstack Posted January 13, 2017 Share Posted January 13, 2017 looks like a snow profile at 36 hours for burke va on 00z namSent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
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