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Deep South Cut-Off November 27-29 2011


FoothillsNC

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Nothing much new to add to this yet, but the RUC does show substantially colder air getting pulled south into the developing cutoff, than the same valid timeframe the GFS (and others) have it. Small scale things like this will probably have a big difference, esp. since pulling even colder air into the cutoff will mean a big difference. It's something to watch. Having a 4 contour spin travel from BHM to AVL with -1 or -2 degrees versus having -4 degree at 850 could be a big difference in actual outcome on p-types.

RUC latest: (notice -6 to -9)

post-38-0-75715900-1322316162.gif

GFS:

post-38-0-55749300-1322316214.gif

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well its certainly possible. This is just my best guess but it could end up sagging further south than on my graphic. Or more north. Its hard to say yet. One thing though, the further south the cutoff becomes, the slower it would be, meaning a whole lot more rain than I have, or any of the models have. This is an evolving situation. If anything, I'm leaning slower and slower with it, and I'm not doing up the rain enough, generally speaking.

Awesome write up as usual Robert :weight_lift: This has been another fantastic system to track so far and I'm looking forward to the much needed rainfall and a surprise or two for some of the crew :snowman::drunk:

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Awesome write up as usual Robert :weight_lift: This has been another fantastic system to track so far and I'm looking forward to the much needed rainfall and a surprise or two for some of the crew :snowman::drunk:

Thanks. You're in for some rain but the lion's share is north and west toward the GA/NC/SC border on this one. The GFS now puts down 5" and I was always suspicious of the lower numbers so I'm still gung ho on a big rain event for most of the southern Apps with this.

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The rate at which the rain falls is going to be a problem most likely for the GA/NC/SC border region. Its showing 1.50 per 6 hours and .75 per 3 hours so if you double that which could be accurate, then it's a pretty impressive rate of rainfall.

post-38-0-87695200-1322325759.gif

The GFS is faster with moving the heavy band out but as with most cutoffs , I won't be surprised to see it remain nearly stationary for much longer. Could be some record daily rainfall amounts in ATL AHN GSP AVL region at some point.

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Awesome write up Robert, great detail as usual. Now if we can get one of these beasts in about 4 weeks we would have about 400 on the board and the pressure would really be on...LOL- glad i got the gutter fixed today!! Im expecting 3+ inches here anywhere up to 5.5" wouldnt surprise me.:raining:Much needed to say the least.

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Pardon me, as I'm an observer, a member and a learner ...

These cut-off lows are, I think, fairly rare down here.

The last of any significance I remember way down on the Suwannee was Dec 21 - 23, 1989, when Gainesville got it's 1" "blizzard". Seems to me it was warm beforehand (like now across the south east) and warm pretty much thereafter.

So - Question - Does anyone have data to indicate what an early/cold cut-off low portends for the remainder of a SE winter? I've scoured and can find no similar set-ups, so am going on "gut" --> pre-Christmas deep SE weather of significance (of this nature, anyway) seems to lead to a warm Jan/Feb. Hope I'm wrong and hope to be told so with some data!

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The only similar early season upper level low that I can remember was the December 11, 2008 storm. It dropped 8 inches of snow in Mccomb, MS and 5 inches in Baton Rouge, LA. I think New orleans even saw accumulating snow. I remember watching webcams of that event while at work that morning.

That winter went on to stink for my back yard. The only accumulating snow I got was from the March 1, 2009 ULL, and I only managed 2.75 inches from that.

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MEM doesn't seem too concerned yet, but the models look good for a significant to major event in west Tn, north Ms and nw AL to me. And considering the models are so far a little warmer than reality regarding the incoming 850 air (notice -9) the core of the cutoff should constrict in this area and have no trouble with temps at dendritic zone to yield snow. Always though during daylight esp. in November at this latitude the boundary is going to be warm, yet the forcing on the tightening 7h low and 850 low all show a very strong deformation band there, so I think more than likely this will rule the p-types, meaning heavy snow at times.

This is Monday , especially into the Monday night period, and the inner white is where my greatest confidence is, but snow may spread deeper into se Ark, and central Mississippi as well as the vort begins to rotate strongly around the 5H center. In fact the colder air is further south into southeast Ark, Miss, Al versus around MEM and sw TN.

post-38-0-76866300-1322402511.jpg

By early Tuesday morning the NAM looks reasonable with the evolution. It has a tightening vort becoming strongly neg. tilt rounding the base of the 5H deep cutoff core, and very cold air (-6 to -9) will be moving in tandem with the moisture developing quickly across northern Alabama and Georgia during the night, roughly from a line BHM to ATL and north. This band will have to be watched for locally quick burst of moderate to heavy snow very late overnight and into early Tuesday , esp. toward the northern parts and as it approaches the srn Apps.

post-38-0-38714100-1322403150.jpg

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Well can't believe I'm doing this here, but the set up for snow seems like it is there. This is kind of a wacky set up where the further south you are in this TROWAL/deformation area..the better your chances of snow. This has a classic TROWAL wrapping around the upper level low. Decent frontogenesis and deformation as the band of snow moves to the south and eventually wraps around the south side of the ULL and moves east. The best area seems like nrn MS right now with the piossibility of it getting into MEM I suppose.

Here the NAM and GFS mid level progs. The NAM has a real good burst of lift near MEM with the coldest air in the mid levels just to the south of MEM. A lot of this cold near the surface will be more manufactured or dynamic cooling.

post-33-0-00352200-1322417929.gif

Here it is going towards ATL, but in weakened form.

post-33-0-65540900-1322417958.gif

Here is the GFS. A little more widespread with the good VV and lift.

post-33-0-97477600-1322417992.gif

post-33-0-39825400-1322418004.gif

The ECMWF also targets nrn MS.

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Well can't believe I'm doing this here, but the set up for snow seems like it is there. This is kind of a wacky set up where the further south you are in this TROWAL/deformation area..the better your chances of snow. This has a classic TROWAL wrapping around the upper level low. Decent frontogenesis and deformation as the band of snow moves to the south and eventually wraps around the south side of the ULL and moves east. The best area seems like nrn MS right now with the piossibility of it getting into MEM I suppose.

Here the NAM and GFS mid level progs. The NAM has a real good burst of lift near MEM with the coldest air in the mid levels just to the south of MEM. A lot of this cold near the surface will be more manufactured or dynamic cooling.

post-33-0-00352200-1322417929.gif

Here it is going towards ATL, but in weakened form.

post-33-0-65540900-1322417958.gif

Here is the GFS. A little more widespread with the good VV and lift.

post-33-0-97477600-1322417992.gif

post-33-0-39825400-1322418004.gif

The ECMWF also targets nrn MS.

This a unique storm in a any year let alone a nina. thanks for taking time to post in the thread.

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A big thanks to all the Mets out there posting on this storm! This is a cool storm to follow and you all have explained a lot about what is going on and about what is going to happen. Thanks to all and this storm is going to be crazy coming in. Were are looking at some 6 inches of rain and they are calling for possibly 2 or three inches of snow in the higher elevations around were i live. Crazy!

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Well can't believe I'm doing this here, but the set up for snow seems like it is there. This is kind of a wacky set up where the further south you are in this TROWAL/deformation area..the better your chances of snow. This has a classic TROWAL wrapping around the upper level low. Decent frontogenesis and deformation as the band of snow moves to the south and eventually wraps around the south side of the ULL and moves east. The best area seems like nrn MS right now with the piossibility of it getting into MEM I suppose.

Here the NAM and GFS mid level progs. The NAM has a real good burst of lift near MEM with the coldest air in the mid levels just to the south of MEM. A lot of this cold near the surface will be more manufactured or dynamic cooling.

post-33-0-00352200-1322417929.gif

Here it is going towards ATL, but in weakened form.

post-33-0-65540900-1322417958.gif

Here is the GFS. A little more widespread with the good VV and lift.

post-33-0-97477600-1322417992.gif

post-33-0-39825400-1322418004.gif

The ECMWF also targets nrn MS.

If im not mistaken, you might want to remove those maps if they are from wrightweather.

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Already some mixed rain/snow occuring around Memphis and will be pretty soon around Columbus to Tupelo as the axis begins to develop there. The system is still strengthening and will grow colder and have strong dynamic cooling involved later today in northern Ms, and sw TN, east ARK. By overnight as the 7H system moves north and even Northwest, the moisture will begin to pivot strongly and wrap around toward northern Miss, and enter a solid northern third to one-half of Alabama early Tuesday morning as likely snow with -6 at 850 air gets pulled ahead of the incoming strong vort that may carry it into northern third of GA by sometime Tuesday. RUC has strong lift with this feature in nw Alabama and north MS by 18 hours so the snow could fall heavily but obviously ground temps and sfc temps will be above freezing. Still Winter storm watches are issued for 1" to 3" , and will depend on where the best bands develop and dynamic cooling.

Developing Stages:

post-38-0-95189300-1322497801.jpg

Current (11 am Mon Nov 28) 850 temps:

post-38-0-23643000-1322497810.gif

post-38-0-70486900-1322497916.jpg

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Nice call on the placement of winter weather, and before the local offices moved on it. You appear to have hit the zone for higher amounts as well. Are you this good for hurricanes, LOL?? If so, I'll be looking your way next August.

Robert's DA MAN! thumbsupsmileyanim.gif

thanks for the nice words. As for tropics, I don't really have a lot of experience with it , not nearly as much as compared to non tropical meteorology, so it's not my forte.

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I'd like to give you a congrats, Foothills. Many of us over at TN weather followed your posts closely. I'll admit that those of us that have been in this game for a while now....none of us really believed this would happen. As always, you give great forecasts and are not afraid to state what you believe...and that is something that is sorely missing amongst meteorologists today (especially broadcast meteorology).

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Robert's our weather clairvoyant, and sage...always showing us glimpses and visions of a glorious possible weather future. Then, when it is coming true, he has to retire and rest,, having been depleted by his efforts :weight_lift: Rest well, my friend, knowing you nailed another one! It is gonna be fun riding along with you again this winter :thumbsup: Tony

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Robert's our weather clairvoyant, and sage...always showing us glimpses and visions of a glorious possible weather future. Then, when it is coming true, he has to retire and rest,, having been depleted by his efforts :weight_lift: Rest well, my friend, knowing you nailed another one! It is gonna be fun riding along with you again this winter :thumbsup: Tony

+1 :wub:

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