Carvers Gap

Glad to see the thread. Will probably be a very light event, but given how cold the ground is, and the cold which will follow...this thread is warranted. Fourth thread this month!!! Interestingly, I was working in the garden yesterday in order to get things ready. The ground in my raised beds is still frozen. I didn't realize it while digging, but I couldn't feel my fingers once it was done.

Don't look now, but the 6z GEFS sort of has the 0z Euro look which had the old GFS look which the GFS lost after having it in the d15-16 time frame. LOL. Modeling is back and forth between cutters and a eastern TN Valley cutter. I am beginning to lean Apps runner or eastern Valley cutter. Makes sense given that is a favored La Nina track, and modeling trend that way overnight. In the LR, you really can't ask for a better look on all three ensembles or February. Sure, it could be a mirage, but if you inject cold into a traditionally active February pattern...fireworks are going to be a likely result. Might be a fun month.

Strong PNA/EPO ridge along with a gradient pattern which is set by a cutter which precedes those systems.

Kind of a cool story. It has been snowing in Jerusalem. Northern Israel received a bunch a few days ago. It is not as rare as some report, but it it still a beautiful place when it snows. I spent two summers in Israel many years ago, so I tend to follow things a little more closely there than I would have otherwise. One of their biggest snows came on December 13, 2013. FUN FACT.....If that date rings a bell, that is the very date that our Tennessee Valley sub-forum was formed!!! Below is a 500 map of the US during Dec 2013 and a map of the the current d10-15(2022) 6z GEFS at 500. What followed this look was a pretty good weather pattern. Obviously, our past December didn't look like that, but that is the pattern over the US when Jerusalem received a ton of snow in 2013. https://www.timesofisrael.com/snow-blankets-jerusalem-transforming-city-into-winter-wonderland/ Thunder in the mountains....snow in Jerusalem. I had some friends living over there at the time. I remember looking at these awesome snow photos. Below is what eventually would follow Dec of 2013. This it the Jan-Feb '14 500mb anomaly map....a pretty good pattern if you dig back through the threads. Maybe we have an active February and/or March coming up???

6z GFS also went big again.

Good write up by MRX.... SR .LONG TERM...(Thursday night through Wednesday)... Key Messages: 1. A wintry mix of of rain and snow is possible on Friday changing to all snow late in the day as colder air arrives. Impactful snow accumulations will be possible across the mountains of East Tennessee and higher elevations of southwest Virginia. 2. Frigid temperatures are expected Friday night through Saturday night with wind chills well below 0 across the higher elevations. 3. Warming temperatures expected early next week with above normal temperatures and increasing rain chances late next week. Discussion: A strong shortwave will dive southeastward from the upper Mississippi Valley on Friday morning with a strong 130 kt jet streak across the Tennessee Valley. A surface cold front extending from a surface low across Canada will slide southeastward with shallow, Arctic air making its way southward on Friday. As this upper jet streak shifts eastward, and this northern shortwave phases with a southern shortwave vort max, the upper trough will amplify across the Eastern CONUS and a surface low will quickly develop and strengthen off the coast of South Carolina. Cross sections show a mid-level frontal slope from 850mb to 500mb across western NC and along the TN/NC mountains late Friday with widespread precipitation near this feature. The GFS and NAM show this expanding shield of light precipitation across far eastern Tennessee and western North Carolina late Friday with the bulk of precipitation east of our forecast area. However, current guidance does place zones along the TN/NC state line within a region of favorable omega and some weak conditional instability beneath the upper trough axis late Friday afternoon which could enhance snowfall rates across the higher elevations of the far eastern Tennessee mountains. As this system moves northeast, NW winds will be relatively strong across the region Friday night with continued low-level moisture within the -12 to -18C DGZ from air sources from the CCB and Great Lakes. This will be a favorable setup for efficient NW flow snowfall and significant snow accumulations across the higher elevations. Will withhold on any Winter Storm Watch for now, but if trends continue to favor potential significant snowfall, winter weather headlines will be needed within the next 24 hours for the mountains. Temperatures will be cold enough on Friday night and Saturday morning that minimum temperatures across the mountains will be in the single digits with wind chills near -10 to -15F across the higher terrain above 3500 feet elevation. A Wind Chill Advisory or Wind Chill Warning may be needed as we get closer to the event. With this very amplified system, the cold, Arctic airmass will settle across the region on Saturday. We will likely see a 48 hour period with most locations below freezing. With this amplified pattern, ridging begins to build back in on Sunday and Monday with temperatures rising above normal by Tuesday of next week. With high pressure in control, expect a mostly sunny sky and dry conditions. Deterministic and ensemble guidance continues to show strong ridging across the Tennessee Valley and Southern Appalachians toward the middle of next week with temperatures above normal. This southerly flow will result in increased moisture across the region with an area of heavy rainfall expected somewhere from the lower Mississippi Valley to the Southern Appalachians. Details on the exact moisture axis are still uncertain, but it appears a more warm and wet pattern is coming late next week with colder air likely in its wake.

Looks about right. TBD snow amounts with the northern stream feature for TRI, SW VA, and SE KY. Looks more nuisance variety to me. Anything from a trace to 2” is possible with cold air already in place and ground temps cold. Southwest facing slopes should see the most. KPT is a tougher sell on this.

True! We were past due for some duds. I think the forum area hit on three out of four (maybe five) storms straight. How do you feel about the pattern after the cutter?

Ditto. Cutters, if cold is available in plentiful quantities (which it is), will often press the cold eastward. Looks to me like the cutter creates a gradient pattern in its wake which the next storm will slide along and then turn northward at some point in its journey across the SE.

12z Euro pushing that next front even further into the forum area. Nice look at 210.

Wow. I missed that. Deep snow pack and cold to the north. -22F real temps. Those would be all-time record lows. There is a reason it is in banter, but 84-85 right there @John1122.

The reason I ask....I usually put a "clock" on weather patterns. Rare to get a pattern to last past 6 weeks. That said, just because the pattern changes does not mean it goes to a pattern which is worse(I am kind of conditioned to that line of thinking though, meaning it gets worse!). Initially, it looked like a flip on LR modeling. Then, it kind of looked like new pattern. However, what the GFS just produced was almost identical to what we say it advertising for the Jan 20-30th time frame - centered slightly west of where it is now. That would bring the storm track onto the eastern seaboard and park it there verbatim. Storm tracks look something like 2/3 cuts west of the Apps, but 1/3 take the low road. That is a very traditional storm track or La Ninas IMHO. So, just trying to figure out if we are stealing a couple of more weeks with the same pattern or is this a new look. I can't honestly tell. There are aspects, as you note, which are slightly different. @John1122, sure looks like the "cold November" correlation may verify this year....

Yeah, details at this range will be scarce. I tagged you int he post above. I thought it interesting to see MRX make a note of that active pattern in their morning discussion. Originally, I really felt like the system after the Nor'Easter would cut west of the entire forum area. I think modeling is adjusting to the idea that maybe trough in the west could be quite temporary and the cold front may push eastward more than LR modeling had to begin with...I think a large scale overrunning event looks plausible for folks to my west, but huge cone of probability at this point.

Stellar write-up by MRX. I am going to post all of it. Great discussion about the short and medium range. Of note, read the last two sentences of the last paragraph @Weathertree2. Key Messages: 1. A mix of rain, snow, and possibly sleet on Friday will changeover to light snow Friday evening with heavier rates in the highest elevations. Accumulations are most likely in the mountains, northern Plateau, southwest Virginia, and possibly portions of northeast Tennessee. 2. Well-below normal temperatures are expected Friday night through Saturday night with wind chills possibly near or below 0 in the higher elevations. A gradual warmup will follow. Thursday through Saturday At the start of the period, a shortwave will be moving out of the Rockies with surface high pressure centered over New England. This approaching shortwave will be the focus for much of the extended period with the initial setup yielding more seasonal and dry conditions locally. Heading into Friday, the aforementioned shortwave will dig significantly with cyclogenesis expected in the western Atlantic ahead of the developing nor`easter. This will result in significant height falls and increasing low-level convergence. Cross sections from the latest NAM/GFS show notable ageostrophic upward motion, well above the dendritic growth zone for much of the area. However, the column does look to be fairly dry in the lower levels at the onset of precipitation in the first half of the day. This will likely inhibit precipitation reaching the ground initially, but the later timing of precipitation suggested by the latest model runs has raised potential for more of it to fall as light snowfall, even outside the mountains. In any case during the overnight period, focus will be on the mountains for more notable accumulation potential as 25+ kts of N/NW flow is expected to persist at the 850mb with continued low-level saturation. With all of these factors in mind and more aggressive snowfall accumulation indications from the NAM and many GEFS members, confidence is high enough for inclusion of wording in the HWO. The focus for better accumulation potential will be in northeastern portions of the area where there is better overall moisture, in addition to the higher elevations of the Plateau, mountains, and southwest Virginia. Then, heading into Saturday, the focus will be notably cold temperatures following significant CAA and far below normal 500mb heights. For places that do see accumulating snowfall, overnight temperatures may fall to the single-digits as surface high pressure will promote subsidence/radiational cooling on Saturday night. With all of these factors in mind, much of the area is likely to remain below freezing from Friday evening until mid-day on Sunday, perhaps longer in some locations. Additionally, synoptically-driven winds early on Saturday when the MSLP gradient increases could produce wind chills in the teens to near 0 degrees, especially in the higher elevations. Below 0 wind chills are looking increasingly likely in the mountains. Sunday through Tuesday By Sunday, the mid/upper trough will have moved to our east with height rises expected into early next week. This will promote a gradual return to near normal temperatures with drier weather also expected during this timeframe. At the very end of the period, deterministic and ensemble models suggest notable troughing in the central U.S. to begin ejecting eastward. This will likely allow for a return of a more active pattern at the end of period and beyond. BW

12z Euro has that system as well, but further to the west. I am guessing that is going to be a cutter for the Plains, but it has trended better for middle and western areas of the state. If it comes to pass, the GFS nailed this from d16. I think there is a pic of it in the banter thread. Regardless of that storm, the pattern that comes after that looks really good. That 6z GFS run looked a lot like last winter's overrunning event. The GFS has some DGEX DNA in it. It has been over-amping stuff this year in crazy ways, but generally getting the placement of the features reasonably correct on a large scale. It seems to have feedback issues when a slp turns to the NE or when it phases. It has done that all winter. I will say this though as a counterbalance to that last opinion, February systems tend to over-perform in my book. Modeling often overestimates how far south those storms will be suppressed and underestimates the strength and precip. In the LR, modeling(ensembles and operationals) look really good. What looked to be a pattern change, now looks like an EPO ridge which has ideal placement. I am a little wary of this flip back to a colder look(after several days of a flip to warm after Feb2). If you remember back during late December when we flipped cold, for a time modeling only had the monster cold front on Jan3rd, and then turned warm after the front. In reality, that was a pattern change. We had a slight warm-up after that front, and then the hammer dropped for good. Right now we have a similar (but opposite) look where a strong cold from drops into the West during early February. At first, modeling had that as the pivot to a warmer pattern over the East. For the past 3-4 days, modeling has trended much colder for the East as it rolls that trough out of the west right back into the East, and then locks it into place. The 6z GEFS is now a complete flip to a very cold look, and its look is one that could deliver a very cold air mass into the US. The 0z CMC has something similar. The EPS has been a few days behind @Mr. Kevin, but it is almost there. The EPS has been less than consistent in the LR. Again, GREAT looking pattern. And again, I am wary of modeling perpetuating the current pattern. For you LR model watchers, does that pattern after the cutter look like a return of the current pattern or is it a new pattern? It looks to me like a variation of the same family of EPO ridges, but the center of the ridge looks further south than the previous pattern. The reason I ask, the current pattern is due to break 4-6 weeks after Jan 3. That would mean that look in the LR is very temporary. If it is a new-is pattern, we may see much of February get cold.

Truly one of the more impressive runs of the NAM(even for the NAM!) that I have seen. It brings snow howling all of the way to the Florida/Georiga border. I have my doubts that it can get the Atlantic feed back this far, but a historic blizzard on the EC certainly seems plausible.

The 18z GFS is loaded for bear after the cutter. Gradient pattern with a cold and an active pattern.

It has more to do with the parabola of a the track. Need that entire parabola to slide a bit west. I honestly don't think it has room at this point, but let's see what happens when the get recon over that energy. I suspect we see one big shift(not idea which way) once models ingest that data. What we really need to hope for in E TN, is for that storm to just amp big time. If that storm is a monster which it could be...If we can get it just barely inside Hatteras with a deeper solution, that snow band might form one of the outer deformation bands as it comes through. Then, we just need that band so set up shop and hold there as the storm wraps up. FWIW, I really like the pattern right after that cutter. Have I said that yet today? LOL

Agree. I am not sure it can work that far back, but was just swinging by to say that. Looks to me like models have a track and are now figuring out the slp is going to be a brute.

Be ready for some changes in modeling when that occurs.

We have definitely run out of the TIM model mojo. Time to put some deposits back in the account. Just thunder...nothing dangerous.

No idea if it is even close to being right, but the 12z Euro ends with the coldest setup of the season IMHO.

February 2015 and comparison to the d10-15 means of the 12z GEPS and GEFS. Not saying that happens, but that is a bit uncanny.

Looks to me like modeling was possibly too quick in breaking down the pattern....OR the new pattern is just a reset of the current Pac pattern which we are in. That is splitting hairs slightly. So, if modeling is correct and is not erroneously perpetuating cold(that has happened before), looks like a warm-up for the first few days of February as cold pulls back into the West....and then the trough quickly gets pushed back eastward. That look late in the runs of the 12z GEFS/GEPS could deliver extreme cold if the look is real.

Kind of raising our eyes past the weekend storm's horizon...Don't look now, but the GEFS now has a full fledged AK block late in its run. That forces the cold eastward. I had at one point though the clock might run out on winter around Feb 2. I think It plausible that we get to at least the 10th... The 12z GEPS has a monster EPO(kind of PNA) block as well. That trough which is going to go out West...it is modeled to roll right back into the East. Good changes/trends from the past couple of days. That may very well be the new pattern...If it is, we may get a couple of bonus weeks of tracking during February. That is a month which is known for frequent storms and changing wavelengths. IF IF that is real, that is a 14-15 type of set-up to me, ie cold an e plentiful precip. If that AK block is real, it might be tough to move.