Jump to content
  • Member Statistics

    17,588
    Total Members
    7,904
    Most Online
    LopezElliana
    Newest Member
    LopezElliana
    Joined

Nov. 27th - Nov. 29th Upper Level Low


LithiaWx

Recommended Posts

Yep. and the GFS Sunday night has a wave of LP develop in western GA overnight to goes due north to near CHA Monday morning, putting a pretty good slug of high winds from the surface up to to 850, so some pretty gusty winds are going to surge north overnight from GA then into SC and then NC east of the low. Should be great rainmaker.

If you're wanting snow you need that 5H cutoff to track to your south on this side of the mtns. If it goes overhead directly , there's a slight chance of snow here but usually the mtns will wring out most of the moisture and we'd need really good rates to get the flake to make it to the ground. The mtns themselves though, no problem. Its going to snow unless the 5H goes well west of there (even then upslope will kick in for them) . The GFS takes the core of the 5h across nw GA to near AVL....so the best chance at snow would be immediately north and west of the side, however since no mtns block nw GA, easily the bands can rotate down to northern Ga. in that setup. We have to see exactly where this goes. Because the 5h track means everything, obviously if it ends up further south and east then ATL would be in the chance at getting some snow and the mtns of TN and NC would really get decent snow synoptically not just upslope.

Haha oh yea I know probably zero chance of that happening..just a :weenie: being a :weenie:!

Link to comment
Share on other sites

  • Replies 748
  • Created
  • Last Reply

Haha oh yea I know probably zero chance of that happening..just a :weenie: being a :weenie:!

well you never know in a cutoff situation. There could be a decent band of precip that works into this region from the west, southwest, from northern GA that comes up I-85 in this type of track. Think that would be early Tuesday or during the day , timing still has to be nailed down.

Link to comment
Share on other sites

Yep. and the GFS Sunday night has a wave of LP develop in western GA overnight to goes due north to near CHA Monday morning, putting a pretty good slug of high winds from the surface up to to 850, so some pretty gusty winds are going to surge north overnight from GA then into SC and then NC east of the low. Should be great rainmaker.

If you're wanting snow you need that 5H cutoff to track to your south on this side of the mtns. If it goes overhead directly , there's a slight chance of snow here but usually the mtns will wring out most of the moisture and we'd need really good rates to get the flake to make it to the ground. The mtns themselves though, no problem. Its going to snow unless the 5H goes well west of there (even then upslope will kick in for them) . The GFS takes the core of the 5h across nw GA to near AVL....so the best chance at snow would be immediately north and west of the side, however since no mtns block nw GA, easily the bands can rotate down to northern Ga. in that setup. We have to see exactly where this goes. Because the 5h track means everything, obviously if it ends up further south and east then ATL would be in the chance at getting some snow and the mtns of TN and NC would really get decent snow synoptically not just upslope.

As it stands now, I think we see at least a mix of rain/snow showers across a good chunk of north Ga and even central Ga. The mid and upper levels are easily cold enough with 850mb temps dropping as low as -6c on the nam. Gfs is warmer with -3 to -4c 850mb temps.

The issue of course will be in the low levels. Best chance to see anything seems to be monday night/early tuesday before daytime when low level temps are coldest. Although temps are cold down to 925mb (-1c to -2c), 950mb temps to the surface are above to well above freezing. What I don't like is the dewpoint depressions being so low in the 950mb to surface range, with lowest dewpoints well above freezing. If we had DPs at or below freezing, it would make a big difference on how much snow reaches the ground. However, gfs does drop dps a bit through the day on tuesday but it doesn't have a lot of moisture as whole by that time.

The nam looks a lot more promising because it's not only colder but wetter through the day on tuesday, which would be promising for at least mixed rain/snow showers. And in the case of the nam, further north does not necessarily mean colder. In fact, the nam has a slightly colder profile in macon at 950mb than in atlanta, athens, and gainesville. Given the nams profile, it would seem some areas have a decent shot of all snow showers if it's heavy enough. Certainly don't expect any accumulations but it would be pretty to see.

So I expect rain/snow mixed showers or possibly all snow because of how cold temps are down to 925mb and how cold the mid and upper levels are. This should allow flakes to be able to survive the AFL longer and possibly counteract the AB temps/dewpoints in the near surface.

Check out the nam's composite reflectivity and the 0z and 06z runs has a slug of enhanced precip swinging around the south side of the low across al/ga/sc.

06z run

06znamreflectivity075.gif

0z run

00znamreflectivity084.gif

Link to comment
Share on other sites

Excellent pbp earlier Steve and great input Robert and Lookout. I hope some of our Ga brethren get to see some flakes fly and the rest of us below the nc mtns get a couple of inches of rain! The last rain flooded my carport due to a clogged gutter, now fixed!

If the 12z is correct you might have a flooded carport again you look to be in the sweet spot for the qpf on this run.

Link to comment
Share on other sites

@48 the ULL looks to start taking form. This run might be further south. Might be a good run for GA...we'll see where it goes

The nam is a nice sight to see , the heights went from 552 to 546 at 48 hours and by 54 hours its wobbling neg. tilt in Mississippi. -4 at 850 covers a pretty big area. Big time wall of water hitting northern GA. Wow what a rainmaker its going to be in the Southern Apps.

Link to comment
Share on other sites

Excellent pbp earlier Steve and great input Robert and Lookout. I hope some of our Ga brethren get to see some flakes fly and the rest of us below the nc mtns get a couple of inches of rain! The last rain flooded my carport due to a clogged gutter, now fixed!

Heights are down to 540 now in BHM to HSV. Tightening cold core = snow thereabouts. Oconee you're in the wettest spot of SC on this setup.

Link to comment
Share on other sites

The nam is a nice sight to see , the heights went from 552 to 546 at 48 hours and by 54 hours its wobbling neg. tilt in Mississippi. -4 at 850 covers a pretty big area. Big time wall of water hitting northern GA. Wow what a rainmaker its going to be in the Southern Apps.

It doesn't stop either at 60 it's got major rains in SW NC...the apps might be flooded. If you're into kayaking downstream is going to be epic come Tuesday if 12z comes to fruition. SC looks to get a good soaking rain as well so Michelle should be happy.

Link to comment
Share on other sites

It doesn't stop either at 60 it's got major rains in SW NC...the apps might be flooded. If you're into kayaking downstream is going to be epic come Tuesday if 12z comes to fruition. SC looks to get a good soaking rain as well so Michelle should be happy.

Yep. This is a good setup, now the nam has its bullseye where I put mine not sure if thats a good sign :yikes:. Pretty large area of 3" or more in NC/SC/GA region, although I bet the usual wet spots will top 5" .

Link to comment
Share on other sites

Heights are down to 540 now in BHM to HSV. Tightening cold core = snow thereabouts. Oconee you're in the wettest spot of SC on this setup.

Yea i saw earlier it was saying 3.5"-4" of rain here with a purple bullseye on oconee. Hopefully this will carry over to winter wx threats as well!

Link to comment
Share on other sites

As I posted earlier, that vort max rotating down the west side of the ULL from Missouri on Monday could reenergize the precipitation on Tuesday as the cold core moves east across GA. NAM still shows this possibility.

Looks like per this run you might be right on the money. It has light QPF sticking around NW GA as the cold is really sweeping through. Hell CLT might get a few flakes at the end per this run unless I'm not reading it correctly. arrowheadsmiley.png

Link to comment
Share on other sites

most of GA , AL, MS is covered with -4 at 850. Pretty large cold pool. The actual 850 low is around Nashville, so the cold air wraps around and underneath the 5H circulation. Amazing to see how it does this, so any moisture thats wrapping around the circulation should pivot across Ms, Al and into GA , with cyclonic curvature. Maybe even come up to NC , via the southwest. Meanwhile, the heavy moisture rotates across western Tn toward northern Miss. at 66 to 72 hours. Its actually colder though further south, so hard to predict the precip type.

The thing with cutoffs, each one wraps moisture bands differently. Some do it well, and some don't, this one looks to have a lot on the far northern then western sides, but not a lot wrapping under the coldest part until it wobbles more east, then by 72 hours its probably snowing pretty hard in part of Tn, northern Ms and northern Al if the def. band can get there.:snowman:

Link to comment
Share on other sites

most of GA , AL, MS is covered with -4 at 850. Pretty large cold pool. The actual 850 low is around Nashville, so the cold air wraps around and underneath the 5H circulation. Amazing to see how it does this, so any moisture thats wrapping around the circulation should pivot across Ms, Al and into GA , with cyclonic curvature. Maybe even come up to NC , via the southwest. Meanwhile, the heavy moisture rotates across western Tn toward northern Miss. at 66 to 72 hours. Its actually colder though further south, so hard to predict the precip type.

The thing with cutoffs, each one wraps moisture bands differently. Some do it well, and some don't, this one looks to have a lot on the far northern then western sides, but not a lot wrapping under the coldest part until it wobbles more east, then by 72 hours its probably snowing pretty hard in part of Tn, northern Ms and northern Al if the def. band can get there.:snowman:

This run hits parts of west central Tn pretty hard, with over 0.50 liquid. The thing is the western portion of this area of heavy precip is very close to the warmer air so someone might be dissappointed. But clearly this is a significant hit for parts of tn.

And as you mentioned, the moisture does swing around into north Ga eventually

NAM_221_2011112612_F75_CREF_SURFACE.png

NAM_221_2011112612_F78_CREF_SURFACE.png

Link to comment
Share on other sites

The Nam is very similar to the GFS in terms of the heavy moisture "sweet spot". It shifts it about 50 miles west of the GFS, and it will probably shift again next run.either way a much needed rain for Ga and SC and NC. I would guess that NeGa sees some flakes out of this. I dont see SC seeing anything other than rain, usually that sharp cut off happens right about the border here esp as it pulls north. It would need to shift a good bit south for me to believe in any type of wrap around for here, thats just the way it works here. I'll take the rain and the temperatures that follow for now and love it.

A rainy cold day may encourage me to put up tree!

Link to comment
Share on other sites

Looks like downsloping winds will cut into rain amounts in NE TN. For those of you who don't live here, that is a real headache on snow events...but prevents flooding rains many times. That 60 hr precip map on the 12z NAM looks like those old precip climo maps where I would wonder how NE SC would get so much rain and SW NC for that matter. I'd hate to be a hydrologist for TVA right now. Going to be moving some water on the main stem next weekend.

Link to comment
Share on other sites

This run hits parts of west central Tn pretty hard, with over 0.50 liquid. The thing is the western portion of this area of heavy precip is very close to the warmer air so someone might be dissappointed. But clearly this is a significant hit for parts of tn.

And as you mentioned, the moisture does swing around into north Ga eventually

Yep, the cold air wraps under the main circulation fora while, but I'm taking this with how most cutoffs work, its going to be hard to nail down specifics, but wouldn't it be wild to have a heavy rainstorm going in one spot in kentucky and then have a heavy band of snow and huge flakes at that, falling just south and west of there in TN. I'm sure no model is right about the bands of moisture but the NAM does look pretty good and thats how I envisioned it happening,so I'm still very much game on for snow or rain to snow to rain and back to snow(it will vary a lot) somewhere in western and middle Tenn, northern Miss, and much of north half of Ala maybe even getting south of BHM and possibly coming directly across the ATL region. If its hard enough it could easily be snow. Things like that we won't know until the bands are seen on radar nicely and rotating. Plus, I still don't trust NAM at 850 yet. I am almost certain within that -4 circle of 850 there will be some -6 or even colder at the core and if moisture can spiral close enough to that area, and probably near BHM to HSV and RMG and CHA region that area could be the sweetspot for heavy wet snow. Its still a crap shoot and will be local, but obviously there's little doubt of some snow in the South.

The Nam is very similar to the GFS in terms of the heavy moisture "sweet spot". It shifts it about 50 miles west of the GFS, and it will probably shift again next run.either way a much needed rain for Ga and SC and NC. I would guess that NeGa sees some flakes out of this. I dont see SC seeing anything other than rain, usually that sharp cut off happens right about the border here esp as it pulls north. It would need to shift a good bit south for me to believe in any type of wrap around for here, thats just the way it works here. I'll take the rain and the temperatures that follow for now and love it.

A rainy cold day may encourage me to put up tree!

Link to comment
Share on other sites

It doesn't stop either at 60 it's got major rains in SW NC...the apps might be flooded. If you're into kayaking downstream is going to be epic come Tuesday if 12z comes to fruition. SC looks to get a good soaking rain as well so Michelle should be happy.

I will be puddle jumping with joy if it happens :wub:

Goofy this morning is still showing some white gold falling close to Tony and Psalm :)

post-279-0-55017900-1322320167.gif

Link to comment
Share on other sites

Looks like downsloping winds will cut into rain amounts in NE TN. For those of you who don't live here, that is a real headache on snow events...but prevents flooding rains many times. That 60 hr precip map on the 12z NAM looks like those old precip climo maps where I would wonder how NE SC would get so much rain and SW NC for that matter. I'd hate to be a hydrologist for TVA right now. Going to be moving some water on the main stem next weekend.

Yeah those mountains are a double edged sword. You can have downsloping winds that cut down on precip totals and you can have upsloping winds that can help produce rain and snow showers.

Link to comment
Share on other sites

well I just saw the NCEP version of NAM and surprised to see the -6 at 850. Impressive! Overall, a very impressive run from what could be a strong storm. The low center wraps west around the circulation and this feeds moisture that will be the def. axis in middle and west Tn, Ky , southern Ill, and stretching down to northern Miss, Al and eventually spread across northern GA and to the western Carolinas by Tuesday morning. The lift and lobes of vort energy spiraling around the strong cutoff combined with ample moisture and good cold -6 degree air should really cause a heavy wet snow band to wrap around and spread a possibly accumulating, clingy type of tree-damaging snowfall to northern Alabama, northwest then northern Ga and middle to western TN, possibly rotating into the western Carolinas by early Tuesday.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...