Jan 25/26 Storm Part IV

[SN_Lover]

My jaw dropped this morning when I saw this....

[FoothillsNC]

BUFKIT just came out... I HAVE GOOSEBUMPS!!!!

Honestly, this has to be overdone... I simpily don't see how KAVL getting 13.9" of snow in 6 hours, the dynamics have to be perfect.

I think that NAM is overdone slightly on QPF with that 7H def. band. I was looking at the Euro and its similar but less, still probably .75" there while its cold enough. One thing though about the NAM, I was just looking at the March 2009 files I have from 48 and 72 hours out on all the models I saved. The NAM was a little too far south in its prog at 48 hours, the RGEM was a dead ringer, so it will be interesting to compare all the models starting now. I'm speaking of both the 5H and 7H fields. Like you said, just a 50 mile jog north could spare a lot of w NC esp. the AVL area, and put most of TN and VA and eastern KY into the best part of the band, likewise, 50 to 75 miles south and its a March 2009 redux maybe. Time of seems to also be similar , atleast here. With a 6 hour window starting around just before dark.

But also the Mtns themselves could wreak havoc, good or bad on the QPF, sometimes they enhance totals , others diminish, thats a hard question to know the answer to. In the March 2009, those mtns played funny games on the 925 temps just east of the escarpment. Either way, I have little doubt that a major dump of really quick , wet snow is coming somewhere underneath that band as it originates in northern Mississippi and strengthens to its max right around the Southern Apps area.

[ams30721us]

From JAN:

[phil882]

Another Insane Nam Bufkit image... and some stats.

Rain changes over to snow at 4pm with 2"+ rates

The snowfall peaks between 5-6pm, with 8.7" falling in a 2 hour period.

Omega through the snow growth column is -55 mb/s... these numbers are just insanity. This is consistent with the rising motion in a thunderstorm... thus thunder snow is not only possible but likely in this setup.

KAVL ends up with 13.9" of heavy wet snow. This will shut down the city for several days.

Ok back to the regularly scheduled normality. Will be interesting to see what the gfs does.

[ams30721us]

I love the Accum map...1"+ for the northern areas haha

[burgertime]

GFS is still to weak with the LP as Srain, if it stays stronger how will that effect the storm? Will that mean our storm has a better chance of deepening and pushing more WAA towards us? Or might it make that ULL stronger? Anyone care to answer?

[strongwxnc]

Thanks for posting this image phil..

Another Insane Nam Bufkit image... and some stats.

Rain changes over to snow at 4pm with 2"+ rates

The snowfall peaks between 5-6pm, with 8.7" falling in a 2 hour period.

Omega through the snow growth column is -55 mb/s... these numbers are just insanity. This is consistent with the rising motion in a thunderstorm... thus thunder snow is not only possible but likely in this setup.

KAVL ends up with 13.9" of heavy wet snow. This will shut down the city for several days.

Ok back to the regularly scheduled normality. Will be interesting to see what the gfs does.

[phil882]

I think that NAM is overdone slightly on QPF with that 7H def. band. I was looking at the Euro and its similar but less, still probably .75" there while its cold enough. One thing though about the NAM, I was just looking at the March 2009 files I have from 48 and 72 hours out on all the models I saved. The NAM was a little too far south in its prog at 48 hours, the RGEM was a dead ringer, so it will be interesting to compare all the models starting now. I'm speaking of both the 5H and 7H fields. Like you said, just a 50 mile jog north could spare a lot of w NC esp. the AVL area, and put most of TN and VA and eastern KY into the best part of the band, likewise, 50 to 75 miles south and its a March 2009 redux maybe. Time of seems to also be similar , atleast here. With a 6 hour window starting around just before dark.

But also the Mtns themselves could wreak havoc, good or bad on the QPF, sometimes they enhance totals , others diminish, thats a hard question to know the answer to. In the March 2009, those mtns played funny games on the 925 temps just east of the escarpment. Either way, I have little doubt that a major dump of really quick , wet snow is coming somewhere underneath that band as it originates in northern Mississippi and strengthens to its max right around the Southern Apps area.

well since the main Deformation band set up over Upstate SC and the southern foothills of NC, the precipitation in NC was all on the northern edge of this feature. The precipitation rates were just enough in Asheville to get a good 2-3" from the event, but the lower elevations just to the east of Mt. Mitchell really suffered because the heavy rates were south, and they didn't have the elevation to cash in with light to moderate snow. If the nam is anywhere close to being right, that shouldn't be an issue this go around, although lower elevations that end up with the lower precipitation rates might get screwed similarly... meaning perhaps upstate SC out to around Charlotte since they are on the edge.

[MichaelJ]

You have me confused now phil, did you mean to say CLT for being on the edge or GSO?

[Cheeznado]

Be careful on getting all excited about the NAM- for it is the NAM. The GGEM is farther north with the 700mb low at 48 hours way up over about Columbia, TN and the surface low north of ATL. I have mostly given up hope here in ATL even in the northern 'burbs,-areas farther north in the mountains are in the game, but there is danger of the system going too far north even up there.

[burgertime]

well since the main Deformation band set up over Upstate SC and the southern foothills of NC, the precipitation in NC was all on the northern edge of this feature. The precipitation rates were just enough in Asheville to get a good 2-3" from the event, but the lower elevations just to the east of Mt. Mitchell really suffered because the heavy rates were south, and they didn't have the elevation to cash in with light to moderate snow. If the nam is anywhere close to being right, that shouldn't be an issue this go around, although lower elevations that end up with the lower precipitation rates might get screwed similarly... meaning perhaps upstate SC out to around Charlotte since they are on the edge.

That's what I'm thinking...CLT might just be too far east to get some snow...still anybodies guess though.

[Justicebork]

Surface low is onshore east of Mobile at 36. 2.5" precip near Valdosta, GA. Precip field is already up near Norfolk.

[Cheeznado]

GFS at 42 farther north than the 06Z run, but a bit deeper.

[DaculaWeather]

You can see on this loop that the moisture is starting to increase more rapidly with small embedded thundershowers already. Also note the energy that advancing rapidly from the NW. http://www.daculaweather.com/ridge_texas_master.php

[burgertime]

ULL is hitting Columbia TN. hard at 48

[burgertime]

12z GFS says NE TN wins big with the ULL

[weatherman566]

Be careful on getting all excited about the NAM- for it is the NAM. The GGEM is farther north with the 700mb low at 48 hours way up over about Columbia, TN and the surface low north of ATL. I have mostly given up hope here in ATL even in the northern 'burbs,-areas farther north in the mountains are in the game, but there is danger of the system going too far north even up there.

I wouldn't give up on NAM though. In March 2009, NAM had a really good handle on the ULL moving over North GA. It correctly forecasted a good snowfall in Athens, while GFS showed lower QPF and no snow. Like we've all been stating, it all matters on the track of the low. The further south, the better off we'll be (if you want snow).

[DaculaWeather]

This track is going to be everything. NOWCast has apparently started. Got the low forming off of Texas... time for RUC and radar!

[burgertime]

12z GFS is a TN, VA special.

[Cold Rain]

To me, the 90%+ RH on the 700mb map is a good indicator as to where the GOOD precip will be. The stronger the upper low, the more pronounced the dry slot becomes along and south of the track of the upper low vort max.

Thanks for the response. I was looking at the RH fields and they matched the QPF fields pretty well. But they weren't aligned along the track of the ULL, so I didn't know if that was right or not. I'd always heard that you wanted to be under the ULL, which according to the Nam, RDU would be. But the QPF and RH fields say that my thinking is in error.

[Justicebork]

12z GFS declares Danville, VA best in show.

[SN_Lover]

12Z NAM snowfall forecast map

[tnweathernut]

I still have thoughts that this ends up even a bit further north than the GFS is showing. I wouldn't be surprised to see the main deform band from central TN into eastern KY Time will tell.

[Cheeznado]

Te fat lady is getting ready to warble for GA,, SC. Charlotte, RDU as the GFS is very much like the GGEM. Congrats NE Tennessee, most of the NC mountains and maybe the far NW foothills of NC .

[FoothillsNC]

the GFS is further north than the NAM slightly, so we'll see which models handle this better, it means the difference between who gets the heavy snow. At 54 hours the 5H center is right over CLT.

[burgertime]

SNE really gets slammed per this run which might bode well for us next week.

[weatherheels]

Its becoming painfully obvious the trend on the ULL is going north. Can't catch a break in the piedmont of NC.

[ams30721us]

Te fat lady is getting ready to warble for GA,, SC. Charlotte, RDU as the GFS is very much like the GGEM. Congrats NE Tennessee, most of the NC mountains and maybe the far NW foothills of NC .

Not so fast for NW GA area IMO...

[Cheeznado]

the GFS is further north than the NAM slightly, so we'll see which models handle this better, it means the difference between who gets the heavy snow. At 54 hours the 5H center is right over CLT.

The GFS is similar to the GGEM and the last two runs of the Euro ensembles. Add that to the fact that the NAM almost never beats the GFS at the 48-54 hour time frame, my money is heavily on the GFS.

[griteater]

Thanks for the response. I was looking at the RH fields and they matched the QPF fields pretty well. But they weren't aligned along the track of the ULL, so I didn't know if that was right or not. I'd always heard that you wanted to be under the ULL, which according to the Nam, RDU would be. But the QPF and RH fields say that my thinking is in error.

Yeah, it's going to vary based on the strength of the upper low. I tend to focus more on the track of the upper low vort max. With the clipper that hit RDU in early Dec, the heaviest precip was along and just north of the vort max track. With this current system, we've got a much stronger upper low, and that tends to setup the good precip farther north as the upper low tracks through.

By the way, I'm disappointed you haven't added the GFS rule in your sig - i.e. that the GFS should be ignored in the mid and long range.