Carvers Gap

Heavy sleet mid-Plateau. I think modeling is having a bear trying to figure out where to place the deformation bands. I have seen modeling banking a band of sleet against the Plateau on recent runs. I am trying to figure that out. I have kicked around maybe a slight downsloping effect with surface winds.

One important note, March qpf totals are often notoriously underdone for systems like this. That is something to remember.

Either way, we take this look 10/10 times and run with it....

That is a good trend for those in the eastern valley. We needed the northwest jog stuffs to stop. Any trend the other direction is welcomed. We don't have a lot of wiggle room if the slp moves northwest.

Yep, you are on the money with that.

Not great news, but as expect(from earlier in the run), this is likely going to send a weak area of slp up the eastern valley.

Still likely to be a big event wherever it goes...vortex is very strong over the Four Corners region.

Pattern looks like it would support a decent northwest jog, but let's see. Sometimes I can be fooled at this range.

12z GFS is rolling...

TRI's issue, if the LR NAM is correct(massive IF), we may be too close to the slp. Been that way all winter. Let's see though. I suspect some in TRI work their way into some snow if the storm verifies.

I "think" most of TRI's snow falls after that window FWIW.

Just checking the 6z Euro. It pops a 988mb slp inside Hatteras. Give me that all day long. No run is perfect and it is not a clean pass. I says this often, most good storms for E TN have some energy transfer. It is very rare to have a clean pass and not have it go too far to our east when that happens.

That is a good look IMO. I think it is more related to the sequence of energy transfer. We generally have some type of rain shadow with nearly every event at TRI, the once exception is if the precip originates to our southwest and come up the valley parallel to both mountain chains. For me, and you have lived this as well, I pretty much know my totals are going to be lower. That said, a well-placed strong storm will overcome a lot of that. This is probably the best looking storm on modeling which I have seen for MBY all winter. It is encouraging to see a solution which is not overly amped. I would think the GFS amping issue is probably a bigger problem during spring with systems having more energy to draw from. And for those who are conservative with their expectations...always a wise move. This should be a storm where folks may be able to easily drive to good totals. Great to be tracking during March...that doesn’t always happen.

Again, I should emphasize that the influx of cold air is going to likely be fast. This might be one time where the cold arrives faster than modeled. This is a pretty stronger system.

As noted, I am not a huge fan the 6z GFS for E TN. It is not a clean pass and involve energy transfer to a secondary/inland runner about 150 miles inside the coast. The initial rams into the southern spine of the apps in northern Georgia and then transfers. That is the absolute closest it can get without sending some ghost of a low up the eastern valley. The ensemble has that, but is much more acceptable....but trends do matter on the operational runs now. If the trend were to continue, it takes the eastern valley out of play. If it stops or slightly reverses...big storm possible for many. Here are some of my favorite looks from the 6z GEFS. Great looking snow mean and nearly perfect placement of the secondary slp. This should be a nice winter storm(major) for someone.

For E TN, I am not a huge fan of the micro-northwest jog on the GFS which is causing the slp to creep towards the east slope of the Apps - and that may just be a GFS bias in play. IDK. That said, the rule again is those who are closes to heavy rain will see the heaviest snow. Maybe the one difference(maybe this is hope and not forecasting) is that this low fires earlier than the other lows this winter which have taken similar tracks. I would be surprised to see things take a long time to change over. The cold just crashed into the back of this storm on pretty much each model. Plateau looks like money for a big one. NE TN is still in question, but latitude will help as the cold front will likely lean northeastward. MRX does a nice job with this write-up. Discussion: A more active weather pattern returns for the extended with the potential for wintry weather this weekend. We begin on Thursday amidst broad southwest upper level flow. High pressure at the surface will keep things dry Thursday and Thursday night with temperatures moderating back to above normal. A weak shortwave progressing through this southwest flow early during the Thursday period will bring an increase in cloud cover but expect this cloud cover to quickly decrease by Thursday afternoon leading to clearing skies. Much of Friday will be quiet in terms of weather as the upper level begin to amplify in response to phasing out west. This upper level trough will quickly dig into the plains by late Friday. Southerly low level flow will not only advect moisture northward, but also advect warmer temperatures poleward with highs on Friday approaching the mid to upper 60`s with near 70 certainly possible in the southern valley. Friday night a frontal boundary will be draped across the lower Mississippi River Valley and across much of the Tennessee Valley and Central Appalachians. High pressure descending from the northern plains will keep this front moving eastward fairly quickly into Saturday morning with much colder air in its wake. Aloft, a deep upper trough will move through the region with height falls overspreading much of the southeast. An area of low pressure is forecast to form in response to increasing upper level dynamics and lift NE along the frontal boundary across the Southern Appalachians into Saturday morning. It will take some time for the atmosphere to moisten Friday afternoon and evening but increasing upper level dynamics will move in sometime around or after 00Z Saturday as a strong jet impinges on the area. Increased PoPs rather sharply after 00Z Saturday with the highest PoPs highlighted between 06-12Z Saturday which is supported by NBM/GEFS/EC guidance. There is rather good agreement on the timing of the aforementioned front with only the most recent NAM being slightly slower. This front will be moving through the area between 06 and 12Z Saturday with much colder air moving in behind it. 850mb temperatures will crash post fropa with temperatures in the -10 to -15 C range by Saturday afternoon. All of this to say that precipitation starting late Friday night as rain will be transitioning to snow. There are increasing signals for heavier snowfall rates as well with upper level ascent maximized within favorable lower thermal profiles. Of course the main question is just how much snow will accumulate and given it is early/mid March adds increasing uncertainty. Things such as recent warm weather, warmer soils, and timing of heaviest snow all will have implications to accumulations. At this point, the lowest confidence in snowfall exists across the valley locations, and higher confidence in accumulating snow exists across the higher terrain. Precipitation will be moving out of the area late Saturday with only high elevation snowfall possible Saturday afternoon and evening. Temperatures on Saturday will be much colder with highs struggling to get above freezing, and nearly 20-25 degrees below normal. Saturday night, skies will be clearing with the center of high pressure situated nearly directly over the area. Light winds, and clearing skies will bring excellent radiational cooling conditions for lows to fall into the teens Saturday night. If we do end up with any snow accumulations then temperatures may even be colder. The much colder temperatures will be short lived however, as increasing heights and southerly flow returns for Sunday into Tuesday. Highs will moderate and by Monday we will be back into the 60`s. Guidance suggests another wave will move into the southern plains and southeast by mid week which could offer increasing chances of precipitation to end the extended period.

Folks, heading to bed! Here is the clown map. I know some of you are staying up for the Euro...bring home the bacon!

Definitely a bit flatter - meaning it is was more ENE than NNE. Likely the GFS is losing some of its amped-ness. Slightly eastward jog. Nice run for E TN, but really most of the forum area is "in" on the run.

Boom. A 997 slp cranking in Upstate SC. Snow is falling in most of the eastern half of the state - big rates in places.

Through 78, looks like the cold front has crashed into the precip shield. Going to be good for someone in the forum area.

Through 72, the flow is a bit flatter which might point to an inland runner/Miller A. We will see.

Through 66, looks to me like the risk of it cutting west of the Apps is lower.

Through 54 looks to me like the pattern is a bit further south. Might that cause more digging and a stronger solution. We will know in about ten minutes....

0z GFS is rolling....

Just using the Euro control for 18z to extrapolate (right or wrongly) the operational...