Jan 25th Winter Weather Discussion Thread

[QC_Halo]

Nam matches Euro from 0z very well. Only one model out there spilling the the dry bone Nada forecast still (GFS). Time for it to get on board.

If its the difference btw nada and ice, I'll take nada. Go GFS.

[beanskip]

Hmmm -- a bit slower at 42 hours with the s/w than the 6z -- good bit slower, actually.

[beanskip]

Wow -- big changes here with 500mb features -- much stronger on 12z run than 6z.

[deltadog03]

GFS, at least in GA is colder Friday morning, but its slower bringing in QPF

[beanskip]

Much jucier QPF at 51 hours.

[MotoWeatherman]

By 15z Friday...GFS is MUCH wetter across all of TN then 6z run.

[Jon]

Wow -- big changes here with 500mb features -- much stronger on 12z run than 6z.

Wetter too over TN thru 54...colder at 850 over NC on onset, about the same as storm moves through...decent trend just trend not there for all snow for northern NC like NAM

[Buddy1987]

Hmmm -- a bit slower at 42 hours with the s/w than the 6z -- good bit slower, actually.

Yes slight difference noted at 42 hrs on 500 don't know if it means anything downstream guess well see here

[MotoWeatherman]

Wow...Much more NAM like with QPF...

[RaleighWx]

GFS is digging the 500mb s/w a bit more and thus better moisture return.

[packbacker]

This is going back to digging the northern stream, back to a phased storm, probably a huge hit for NE, LOL

[eyewall]

850 line retreats to the VA border at 60 hrs but not as dry. Haven't had time to look at thicknesses yet.

[Poimen]

GFS is wetter...but warmer than the NAM.

[beanskip]

Nasty ice storm set up for much of N.C. You could see it coming with 500 features.

[eyewall]

Partials at 60 hrs:

[RaleighWx]

Again use with caution

 

[rduwx]

For the RDU area the 850's are warmer. I haven't looked at the temp profile yet but the gfs looks less like a sn profile and more like a zr.

[RaleighWx]

Literally suggests a quick 0.5 to 1 inch for many to a wintry mix.

[WeatherNC]

Nasty ice storm set up for much of N.C. You could see it coming with 500 features.

Roughly doubles amounts over the state compared to the previous run, so we went from 1/8" to about a third.  Step in the wetter direction, which is a good sign considering its the gfs, wonder if the other globals will follow.

[eyewall]

GFS suggests quick snow hit then ZR. Slower timing is likely a factor here as the parent high weakens and perhaps a bit more warming before we can lock in any CAD.

[Brick Tamland]

Good trend for the GFS. Looks like we're going to get something for sure. Now just a matter of how much snow and how much ice.

[Jon]

12z GFS Meteoogram has RDU at 0.25" all ice

[MotoWeatherman]

GFS still kills the QPF in the carolinas compared to places further west.  If the GFS verifies north GA would have some issues on Friday with ice and that amount of QPF.

 

 

[Marion_NC_WX]

Looking at the profiles...after a brief start as snow, KMRN (Morganton-Lenoir Airport) goes over to a sleet signature as there will be a warm nose of around +1 between 750-800mb and then it quickly cools back down to -8 at 900mb all the way down to the surface.

[Poimen]

12z GFS Meteoogram has RDU at 0.25" all ice

 

yep...I'm afraid ZR is in our future here...thankfully it doesn't look like it will be too heavy.

[rduwx]

Good trend for the GFS. Looks like we're going to get something for sure. Now just a matter of how much snow and how much ice.

I wouldn't go as far as saying we're going to get something for sure. Do you remember Friday? Do you remember getting mad and saying the models couldn't even be trusted the day before an event? Just remember there are no sure things for the SE.

[packbacker]

Good trend for the GFS. Looks like we're going to get something for sure. Now just a matter of how much snow and how much ice.

 

Not so sure, with the stronger northern energy digging much further south, the primary low is to are north which warms us, if it gets stronger we could flip to rain very easily.

[MotoWeatherman]

Both GFS and NAM say NE GA will get a winter storm of the ice variety.  Both NAM and GFS have temps of 26-27 at the surface at 1pm Friday for the areas NE of ATL near the mountains. 

 

Date: 54 hour AVN valid 18Z FRI 25 JAN 13Station: 34.59,-83.93Latitude:   34.59Longitude: -83.93-------------------------------------------------------------------------------LEV PRES  HGHT  TEMP  DEWP  RH  DD   WETB DIR SPD THETA THE-V THE-W THE-E   W     mb     m     C     C    %   C     C  deg knt   K     K     K     K    g/kg-------------------------------------------------------------------------------  0 1000   188                                                                 SFC  964   480  -3.2  -6.0  81  2.8  -4.1 146   5 272.8 273.2 271.0 279.8  2.53  2  950   595  -4.6  -6.5  86  1.9  -5.3 154   6 272.5 272.9 270.7 279.2  2.46  3  900  1019  -3.4  -3.7  98  0.3  -3.5 203  23 278.0 278.5 275.1 287.0  3.23  4  850  1479   3.6   3.5  99  0.2   3.5 228  48 290.0 291.0 284.0 306.5  5.78  5  800  1973   3.5   3.2  98  0.3   3.3 242  55 294.9 295.9 286.2 312.4  6.01  6  750  2495   1.2   0.8  97  0.4   1.0 249  57 297.9 298.9 286.7 314.0  5.43  7  700  3048  -1.7  -2.1  97  0.4  -1.9 253  58 300.6 301.5 287.0 314.8  4.69  8  650  3635  -4.5  -5.2  95  0.7  -4.8 262  64 303.8 304.6 287.5 316.1  3.99  9  600  4262  -7.9  -8.7  94  0.8  -8.2 269  70 306.9 307.6 287.8 317.3  3.30 10  550  4934 -11.6 -12.1  96  0.5 -11.8 275  72 310.3 310.8 288.5 319.1  2.76 11  500  5659 -15.7 -16.2  96  0.4 -15.9 277  74 313.9 314.3 289.0 321.0  2.17 12  450  6447 -19.8 -20.5  94  0.7 -20.0 272  74 318.3 318.7 289.9 323.9  1.66 13  400  7315 -23.7 -24.8  91  1.0 -24.0 265  87 324.1 324.4 291.3 328.6  1.28 14  350  8278 -30.8 -31.5  93  0.7 -30.9 264  93 327.3 327.4 291.7 330.1  0.79 15  300  9355 -38.3 -38.6  97  0.3 -38.3 267 102 331.4 331.5 292.6 333.1  0.45 16  250 10580 -49.2 -49.2 100  0.0 -49.2 270 112 332.9 333.0 292.7 333.6  0.17 17  200 12009 -58.3 -59.5  86  1.2 -58.3 279 123 340.5 340.5 294.5 340.8  0.06

[Shawn]

12z GFS too warm for the CAE area.  12z NAM was a bit of ice for us though!  Waiting for GGEM and then switching to hi-res models for accuracy!

[Lookout]

Would be nice to see the nam gain support from other models. It can be used in conjunction with them, but alone it is virtuallly useless this far out IMO. If the euro/gfs/ggem can come in with a higher QPF output, it could be time to get excited for something more than a nuisance event. We shall see.

 

Agreed completely. This is nice to look at it but I really want to see other models have this much precip. Taken at face value though this is a nice little winter storm for most. Given the very cold temps at the surface combined with a deep cold layer (much colder than usual in fact and given how light the precip starts at, such cold temps and the depth will help  areas dealing with the warm nose to probably start as sleet.

 

Looking at charlotte's sounding, for example, it looks to start as snow, then it loos like sleet for several hours as the warm layer is rather cool and with a subfreezing layer from 900mb to the surface and as cold as around 20 at 950mb, certainly supports that.  Areas with appreciable amounts of sleet which then turns over to freezing rain will really have a mess on the bridges and roads for sure, even if it's half of what the nam is showing.

 

The boundary layer temps are very impressive, especially around 900 to 950mb..so it will be a battle between the warm nose aloft to the south and those temps. I didn't think we would see much sleet in ga and we have a much deeper and warmer warm nose aloft but the precip starts off rather light, so that gives it more chances for it to freeze going through a boundary layer that has temps in the low 20s down into northeast ga

 

The carolinas are really impressive. HKY has a 900mb of 14 at hour 51 (which is snow)  and  gsp (which looks like sleet)  has a 950mb temp of 18 at with precip falling. Places like gainesville, hartwell, etc have a min boundary layer temp of around 21 on this run around that time.

 

Temps do not rise above freezing in ne ga along the 85 corridor and probably a little south of that.

 

That said, the gfs is a little slower and further north with the precip. Temps start off very cold, upper 20s with dewpoints in the upper single digits/around 10. When precip really gets going, 18z or after temps still around 29/30 and wetbulbs around 26 for ne ga.

 

IF the precip shield is further north, some slight warming can be expected but I still don't see most places rising above freezing here in NE ga. But it would be better if the precip shield was a bit further south. On the gfs/nam the best areas for significant accumulations are at and above i-85. The favored areas of from gainesville up toward toccoa, look to be in the bullseye (mountains will be warmer due to waa aloft).

 

Looks like favored areas of the western carolinas, hky, etc, will have several hours of snow before going to sleet.

 

Will be interesting to see if precip streaks ahead of model predictions, as if often the case.

 

 

 

looks like we at least have a threat and hopefully a set up for winter wx in the se for the first time since the year before last!  appears that ne ga will be in the potential for ice (which historically has usually been the case).  i guess its about time since the last real ice storm here was dec 2005.  a few minor icing "events" (.10), a few forecasted, but nothing in over 7 years.  will be interesting to see if we really do get the cad set up this time

 

You are looking good at the moment for sure. In fact, you are going to be very cold for a wedge, low to mid 20s per both models.

 

I'm just happy to have a damn wedge with precip to follow. I know it's not a huge event but it is rather unique in how cold the boundary layer temps are, especially initially.