mackerel_sky Posted January 7, 2018 Author Share Posted January 7, 2018 The WPC probabilities of ZR , have went up quite a bit for N Ga and into the upstate SC area! I know it's only ice accretion of .01, but this morning had 0 for the upstate, now som 30-50% chances. I think we drizzle before the main precip gets here and that will cause big issues! Think NYE Asheville kind of stuff Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 7, 2018 Share Posted January 7, 2018 1 minute ago, mackerel_sky said: The WPC probabilities of ZR , have went up quite a bit for N Ga and into the upstate SC area! I know it's only ice accretion of .01, but this morning had 0 for the upstate, now som 30-50% chances. I think we drizzle before the main precip gets here and that will cause big issues! Think NYE Asheville kind of stuff Also, isn't it that the heavier freezing rain there is, the more chances of drawing the WAA down to the sfc to warm temps? I know that when it's a borderline situation (31-32), if it's raining too heavily, it won't freeze but will just runoff. Looks like what we're dealing with is something that will freeze right away. Link to comment Share on other sites More sharing options...
drfranklin Posted January 7, 2018 Share Posted January 7, 2018 just some observations from a non-meteorologist: the radar returns in the mid-South look greater that what some models have predicted - also, I only reached a high of 32 today - slowly falling, now at 31.5 Link to comment Share on other sites More sharing options...
POWERSTROKE Posted January 7, 2018 Share Posted January 7, 2018 High of only 29 today. Any light mist will make roads slick quickly. Are we still looking at mid morning before moisture gets over mountains or sooner? Link to comment Share on other sites More sharing options...
Hammer Posted January 7, 2018 Share Posted January 7, 2018 I'm not sure if this will have any implications on what might happen tomorrow, but I was forecast to be somewhere near 37 today; only managed 34.4. Currently 33.9 with a dp of 10. My highest temp all week has only been 36.4 yesterday, and coldest was 7.9 on the 2nd; everything is basically frozen, so I'm sure it will take some things outside to warm above freezing even when the actual air temp goes above.Same here. Most of CHEROKEE County has been below 32 (or near it) for some time. I am seeing ice on the Etowah River and Allatoona has up to 4” of ice in places. . Pro Link to comment Share on other sites More sharing options...
mackerel_sky Posted January 7, 2018 Author Share Posted January 7, 2018 10 minutes ago, drfranklin said: just some observations from a non-meteorologist: the radar returns in the mid-South look greater that what some models have predicted - also, I only reached a high of 32 today - slowly falling, now at 31.5 It's a bit early for radar hallucinations! Just kidding. But yeah , temps were supposed to hit 40 today. This is definitely a nowcasting situation. I think there are so many little things that could be crucial: SE flow drizzle, more precip, earlier arrival of precip, the " streak " of moisture that gets here way ahead of the main storm. Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 7, 2018 Share Posted January 7, 2018 5 minutes ago, mackerel_sky said: It's a bit early for radar hallucinations! Just kidding. But yeah , temps were supposed to hit 40 today. This is definitely a nowcasting situation. I think there are so many little things that could be crucial: SE flow drizzle, more precip, earlier arrival of precip, the " streak " of moisture that gets here way ahead of the main storm. So many variables that will make or break the forecast, that we just don't know yet. It's times like these where forecasters really earn their money. But like you said, definitely nowcasting. It might not amount to much but only a touch of freezing drizzle on already frozen surfaces will cause chaos. 33.3/10 Link to comment Share on other sites More sharing options...
Lookout Posted January 7, 2018 Share Posted January 7, 2018 34 minutes ago, CummingGaSnow said: ATL always has a tendency to rise above freezing even with drizzle or something falling, whereas the NE suburbs over to Athens and up to Gainesville and onward will stay put. IF we can get precip to fall early enough (even as virga) that will still strengthen a mesoscale in-situ wedge and lock it in place, and once that happens it's very hard for anything to erode it. Yep.... but what makes this one different is atlanta/we all start off a lot colder than usual. In most situations similar to this, we are 31 to 35 and have to rely on evap cooling to even bring us down..and after saturation we..on average...only get to 29 to 31 north and east of town with the freezing line somewhere around atlanta. In this case, everyone starts off at 26 to 28 (with wetbulbs even lower) . That is unusual and if there is enough precip that we fully or mostly saturate.... despite the overall light precip amounts, will result in a likely prolong period of subfreezing temps..even for atlanta....(especially if it happens early) and lasting into the nighttime hours 18z gfs coming in a little wetter too. (as well as the rgem) Not as wet as the nam but wetter none the less. That band of heavier precip it has over central ga i was referencing earlier is getting awfully close. this run is 4 to 7 degrees at 18Z tomorrow than the prior run around the metro just because of slightly more precip. Due to the very cold initial conditions, might have to watch areas south of town getting more than expected if that band materializes sooner...before it warms up. Link to comment Share on other sites More sharing options...
mackerel_sky Posted January 7, 2018 Author Share Posted January 7, 2018 Radar does look juiced! Already virga in N AL! Link to comment Share on other sites More sharing options...
NEGa Posted January 7, 2018 Share Posted January 7, 2018 It’s 31 here with a dew point of 3 lol. As cold as it’s been for so long and with these temps it could be an instant skating rink tomorrow Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 7, 2018 Share Posted January 7, 2018 8 minutes ago, Lookout said: Yep.... but what makes this one different is atlanta/we all start off a lot colder than usual. In most situations similar to this, we are 31 to 35 and have to rely on evap cooling to even bring us down..and after saturation we..on average...only get to 29 to 31 north and east of town with the freezing line somewhere around atlanta. In this case, everyone starts off at 26 to 28 (with wetbulbs even lower) . That is unusual and if there is enough precip that we fully or mostly saturate, despite the overall light precip amounts, will result in a likely prolong period of subfreezing temps..even for atlanta....and lasting into the nighttime hours. 18z gfs coming in a little wetter too. Not as wet as the nam but wetter none the less. That band of heavier precip it has over central ga i was referencing earlier is getting awfully close. this run is 4 to 7 degrees at 18Z tomorrow than the prior run around the metro just because of slightly more precip. Due to the very cold initial conditions, might have to watch areas south of town getting more than expected if that band materializes sooner. That would be lights off to most, too; unfortunately. Hopefully we can get something in between lights off and almost nothing. Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 7, 2018 Share Posted January 7, 2018 2 minutes ago, NEGa said: It’s 31 here with a dew point of 3 lol. As cold as it’s been for so long and with these temps it could be an instant skating rink tomorrow I'm watching here too. 33.2/10. Of course, if you get precip up there before you can recover, then yikes! Link to comment Share on other sites More sharing options...
GAdawg Posted January 7, 2018 Share Posted January 7, 2018 Radar looks to have a good flow coming up from the gulf into LA... Link to comment Share on other sites More sharing options...
mackerel_sky Posted January 7, 2018 Author Share Posted January 7, 2018 31/1 currently! Pressure 30.50 -amazing! Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 7, 2018 Share Posted January 7, 2018 Clouds on the increase here. Shouldn't fall too much more here, especially since I'm on a hill and cold air drains away at sunset. 32.7/10 Link to comment Share on other sites More sharing options...
Red1976Red Posted January 7, 2018 Share Posted January 7, 2018 44 minutes ago, POWERSTROKE said: High of only 29 today. Any light mist will make roads slick quickly. Are we still looking at mid morning before moisture gets over mountains or sooner? I think well after lunch time that far east. Link to comment Share on other sites More sharing options...
JoshM Posted January 7, 2018 Share Posted January 7, 2018 14 minutes ago, mackerel_sky said: 31/1 currently! Pressure 30.50 -amazing! Bout the same here, 30.49 Pressure, 28/0 Link to comment Share on other sites More sharing options...
mackerel_sky Posted January 7, 2018 Author Share Posted January 7, 2018 1 minute ago, JoshM said: Bout the same here, 30.49 Pressure, 28/0 Really a shame we can't get a ton of moisture in here and have it be all snow and sleet. Pre storm conditions are about as good as you can get around these parts! Think we get down to 24/25 tonight, clouds aren't too thick yet Link to comment Share on other sites More sharing options...
POWERSTROKE Posted January 7, 2018 Share Posted January 7, 2018 21 low for us tonight. Already down to 25 now Link to comment Share on other sites More sharing options...
Hammer Posted January 7, 2018 Share Posted January 7, 2018 35 / 19 right now. . Pro Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 7, 2018 Share Posted January 7, 2018 1 minute ago, Hammer said: 35 / 19 right now. . Pro Your dp seems too high, compared to surrounding obs. Just sayin'. I'm at 32.3/10. Link to comment Share on other sites More sharing options...
Hammer Posted January 7, 2018 Share Posted January 7, 2018 Your dp seems too high, compared to surrounding obs. Just sayin'. I'm at 32.3/10.Going off of local weather station - I am about 150 yards from the lake - will that affect it?. Pro Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 7, 2018 Share Posted January 7, 2018 5 minutes ago, Hammer said: Going off of local weather station - I am about 150 yards from the lake - will that affect it? . Pro To an extent perhaps, but I don't think THAT much. I think most dp's in the area are between the upper single digits to lower teens at most. For instance, I have my station's humidity calibrated 2% higher to coincide with another sensor I have and I'm still only reading between 10-11. Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 7, 2018 Share Posted January 7, 2018 Below freezing now. 31.7/10. I wonder how long tomorrow it will take to get above freezing. Link to comment Share on other sites More sharing options...
Lookout Posted January 7, 2018 Share Posted January 7, 2018 59 minutes ago, CummingGaSnow said: That would be lights off to most, too; unfortunately. Hopefully we can get something in between lights off and almost nothing. taking a closer look at soundings, if you want temps to stay below freezing longer.. The fact the precip is so light is actually a positive because if it was heavy... temps would likely rise to freezing or above sooner...as the subfreezing layer is very shallow...only extending up to 975mb or just above it, by tomorrow afternoon. Normally, we would like to see that extend up to 950mb. Almost always if it extends to 950mb, it stays below freezing if it's cold enough initially. But given the airmass is so cold, 975mb is probably just enough to keep temps below freezing all day and into the evening IF precip is light to moderate. If we were dealing with heavier precip, drag and quick latent heat release would bring temps up faster because 950mb temps soar after noon tomorrow...as high as 7 or 8c by 0z tuesday. Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 7, 2018 Share Posted January 7, 2018 8 minutes ago, Lookout said: taking a closer look at soundings, if you want temps to stay below freezing longer.. The fact the precip is so light is actually a positive because if it was heavy... temps would likely rise to freezing or above sooner...as the subfreezing layer is very shallow...only extending up to 975mb or so by tomorrow afternoon. Normally, we would like to see that extend up to 950mb. Almost always if it extends to 950mb, it stays below freezing if it's cold enough initially. But given the airmass is so cold, 975mb is probably just enough to keep temps below freezing all day and into the evening IF precip is light to moderate. If we were dealing with heavier precip, drag and quick latent heat release would bring temps up faster because 950mb temps soar after noon tomorrow...as high as 7 or 8c. So what you're saying is if we have a prolonged period of freezing drizzle/light rain, that will help stabilize temps, and keep the heavier rain from dragging the warmer temps down to the sfc? Honestly, I don't wanna be out of power, so I'm really hoping it's just enough to look pretty. Also, it's been a long time since we had an icestorm that froze to the ground too. I love hearing the ground crunchy from ice. Your area just NE of Athens always does extremely well in these kinda situations if you can get precip in fast enough. You might be taking some georgeous pics come 24+hours from now. Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 7, 2018 Share Posted January 7, 2018 News channels are warming temps (as usual) far too fast given they are predicting an early (morning rush hourish) start to the precip. IF precip can indeed start that early, there are gonna be some major temp/precip forecast type busts tomorrow, let alone the possibly greater ice accreations. It's gonna be an interesting 12-24 hours to watch how things transpire. Link to comment Share on other sites More sharing options...
Red1976Red Posted January 7, 2018 Share Posted January 7, 2018 After some substantial collaboration with our neighboring western and southern neighboring offices, will start a winter weather advisory beginning around the morning commute. Dry air will delay onset of wintry precipitation from the New River Valley up through the Shenandoah Valley and the foothills until after the morning commute. In most of these areas, would expect an initial precipitation type of wet snow. A southwest to northeast transition to sleet/freezing rain and then plain rain is expected as temperatures warm aloft and surface temperatures respond in kind as well, but the air and pavement will be slower to do so. In the southeastern counties outside the Advisory area, some greater warming appears possible given a later precip start time. My confidence for this area is lower than points northwest in the Advisory areas. Link to comment Share on other sites More sharing options...
WarmNose Posted January 8, 2018 Share Posted January 8, 2018 GSP is going to get more than they bargained for in the AM imo Link to comment Share on other sites More sharing options...
jtgus Posted January 8, 2018 Share Posted January 8, 2018 41 minutes ago, Red1976Red said: After some substantial collaboration with our neighboring western and southern neighboring offices, will start a winter weather advisory beginning around the morning commute. Dry air will delay onset of wintry precipitation from the New River Valley up through the Shenandoah Valley and the foothills until after the morning commute. In most of these areas, would expect an initial precipitation type of wet snow. A southwest to northeast transition to sleet/freezing rain and then plain rain is expected as temperatures warm aloft and surface temperatures respond in kind as well, but the air and pavement will be slower to do so. In the southeastern counties outside the Advisory area, some greater warming appears possible given a later precip start time. My confidence for this area is lower than points northwest in the Advisory areas. Where? You do not have a location listed or mentioned in your post Link to comment Share on other sites More sharing options...
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