Carvers Gap

LOL. My point and click is also a rain/snow mix for the time John mentioned. Freeze watches and warnings have now been hoisted for many areas for tomorrow night. Knoxville isn't under an advisory currently, but have to think later shifts might likely add them regarding frost. Just a quick point/click has frost there late Friday night and Saturday morning. I am again going to add the entire MRX discussion for posterity. Snow above 3,500' feet is expected with light accumulations noted. Highs on Friday and Saturday will be 25-30 degrees colder than last May on those same dates. Truly, summer began last year during April and was in full swing by May. During the latter half of May last year, we had temps in the upper 80s and hit 90 on a few days. Who knows? That may still happen. But Friday and Saturday will push record lows and record low max temps. National Weather Service Morristown TN 712 AM EDT Thu May 7 2020 .UPDATE... FOR 12Z AVIATION. && .SHORT TERM...(Today and tonight)... The frost advisory will be allowed to continue as is for early this morning. Surface high pressure centered to our southwest will drift southeast and east and will extend into our area today. We will see plenty of sunshine today but temperatures will still be below normal. Tonight will see moisture begin to increase ahead of the next low pressure system ejecting out of the Plains. Low/mid levels of the atmosphere will initially be quite dry which will delay any precip onset, but as isentropic lift increases late tonight we may see a bit of light rain begin reaching the surface especially western areas, so will include low PoPs all but far northeast TN. Temperatures tonight will be below normal as well. LW .LONG TERM...(Friday through Wednesday)... The main weather stories for the extended remains the following: 1) Unseasonably strong upper trough across the eastern half of the nation through Monday, then heights began to increase early next week. Standard anomalies for 500mb heights and temperatures are well below normal especially for this weekend. Near record or record lows are anticipated for Saturday and Sunday mornings with areas of frost. Freezing temperatures are anticipated for parts of southwest Virginia, northeast Tennessee, far east Tennessee Mountains, Plateau, and southwest North Carolina. 2) An unusual late season snow is expected across the highest peaks of southwest Virginia (High Knob) and far east Tennessee Mountains, such as Roane and Smoky Mountains. 3) Another significant headline is the expected high winds across the far east Tennessee Mountains and Foothills Friday. Now for a closer look... For Friday, a strong short-wave will move quickly east southeast across the Ohio and Tennessee valleys into the Appalachians. The associated upper jet dynamics will be strongest over the Ohio valley and northern sections of the forecast area. Upper system will induce a fairly strong surface cyclogenesis. This surface low will tighten the pressure gradients across the region with a fairly strong low- level jet. The 850mb winds will increase to 50-60kts producing breezy/windy conditions, especially for the Mountains where a High Wind Watch is issued. The strong low-level jet will also increase the isentropic lift across the Tennessee valley and southern Appalachians. Widespread rain showers are expected. Due to limited Gulf moisture return, instability will be non-existent with this system and will keep thunder out for Friday. For Friday evening and night, robust northwest flow strengthens pulling colder air into the region and producing orographic lift. Vertical temperature profile becomes unseasonably cold allowing rain showers to change to snow in the evening. Snow accumulations of 1 to 1 1/2 inches are anticipated over the higher elevations, generally at or above 3500-4000 feet. Sky will gradually clear from west to east as a ridge of high pressure builds into the area late Friday night/early Saturday morning. Due to clearing sky, diminishing winds, and unseasonably cold air-mass, patchy to areas of frost are expected with some freezing temperatures anticipated over much of the Plateau, southwest VA, northeast TN, far east TN Mountains, and southwest NC. A freeze watch has been issued. For Saturday and Sunday, surface ridging and dry northwest flow aloft will produce dry conditions but unseasonably cool conditions. Another round of frost/freezing temperatures are expected Sunday morning. For late Sunday night and Monday, another weaker short-wave will move into the Ohio and Tennessee valleys. Dynamics is weaker with limited moisture. Will keep low chance PoPs for southwest Virginia and northeast Tennessee. Elsewhere, dry conditions. For Tuesday and Wednesday, upper flow will become more zonal then increasing ridging by mid-week. Dry conditions and a warming trend are anticipated. DH

For posterity...I usually don't post all of the disco, but this is a pretty unique event and will probably be worth a read during later years. Frosts, freezes, and high elevation snow forecast. Currently snowing at Newfound Gap - posted a tweet in the obs thread. National Weather Service Morristown TN 329 PM EDT Wed May 6 2020 .SHORT TERM... (Today through Tomorrow)... Currently a trough is swinging through the eastern half of the U.S. and along the axis of it we`re a line of showers and a few flashes of lightning as it makes it`s way east across the Appalachian Mountains. Expect these showers and isolated thunderstorms to be east of the mountains over the next few hours. Some very isolated weak showers may move in from Kentucky into the evening hours, but coverage of these looks to be pretty sparse and QPF amounts will be light if any do form. Winds will remain breezy as air fills in behind the front. Tonight as cold air continues to pour in from the northwest the skies will also be clearing out at the same time. This combination will help lead to unseasonably cold temperatures across the region. Overnight lows will dip into the 30`s for most locations and possibly near or below freezing at the tops of the southern Appalachian Mountains. A frost advisory will be in effect for southwest Virginia and northeast Tennessee tonight. There is a chance that winds remain elevated enough that it prevents widespread frost from forming, but with frost occurring this late in the season decided to err on the side of caution and issue an advisory for areas who`s overnight lows drop into the mid 30`s. For tomorrow expect to see sunny skies with dry air remaining over the area. With the sun expected to shine most of the day tomorrow temperatures will be several degrees warmer than what we experience today. ABM .LONG TERM...(Thursday Night through Wednesday)... The main story of the long term period is the unseasonably cold weather in store for much of the eastern half of the nation, including our forecast area. This will include the possibility of near record lows over the weekend, along with some areas of frost and freezing temperatures. The higher elevations as well as the northern half of the forecast area will be most susceptible to these conditions. Currently only have one significant rain producing system in the period, which is set to move through the area early Friday. More on that in a second. As mentioned, unseasonably cool/cold weather is on tap for the southern Appalachian region during the long term. A strong upper trough will remain over the eastern United States during the period, with a couple of embedded shortwaves passing through. The first, and strongest of these disturbances, will move through on Friday. This short-wave will move quickly east southeast across the Ohio and Tennessee valleys into the Appalachians. The associated upper jet dynamics will be strongest over the Ohio valley and northern sections of the forecast area. Upper system will induce a fairly strong surface cyclogenesis. This surface low will tighten the pressure gradients across the region with a fairly strong low-level jet. The 850mb winds will increase to 50-60kts producing breezy/windy conditions. Models do show some convective trends in QPF values to our southwest, along/ahead of the associated cold front. However, think just showers will be present in our CWA due to the lack of influx of Gulf moisture into the area before the front arrives. For Friday night, showers end pretty quickly and should see skies clearing out pretty rapidly. There could be a changeover to snow in the higher elevations late Friday evening before precipitation ends, but this would be brief and little to no accumulation is expected. Skies begin to clear out Friday night, and with strong high pressure building in from the northwest, and weakening winds, temperatures are likely to drop into the 30s even in the south. Northern valley, southwest Virginia, and higher elevation locales will likely see lows in the 20s. Areas of frost seem a high likelihood. Will hold off on any frost related headlines right now as we have some out for tonight. However, expect these to be considered for Friday night in the coming shifts. For Saturday and Sunday, surface ridging and dry northwest flow aloft will produce dry conditions but unseasonably cool. Another round of frost/freezing temperatures are expected Sunday morning. For late Sunday night and Monday, another weaker short-wave will move into the Ohio and Tennessee valleys. Dynamics is much weaker and moisture is even more limited than with Friday`s system. Limited PoPs to slight chance values across southwest Virginia and far northeast Tennessee for now since there is notable timing and coverage differences between the models right now. For Monday into Tuesday, another strong continental surface high moves into the region from the northwest. This will bring a reinforcing shot of cold, dry air to the area. While not as cold as the air mass over the weekend, expect to see lows remain in the 40s to perhaps upper 30s heading into early next week. A pattern change looks in the offing heading into the middle of next week. Temperatures will begin to moderate and there may be a weak disturbance moving through the region on Wed for a slight chance of showers for the time being. Pretty large discrepancies with how the pattern evolves Tue onward so low-end slight chances will suffice for now.

NWS predicting frost tonight, Saturday, and Sunday mornings for TRI. Point and clicks are forecasting lows at or below freezing over the weekend in the same region. Looks like one last potential cold shot Tuesday AM(keep an eye on Weds as well), and then we may be out of this until next fall. For TRI, the 6z GFS is showing potential for 5 frosts and the Euro 3. Either way, cold is on the way. As for Knoxville, temps continue to look marginal. The Central Valley appears most at risk this weekend for widespread frost. Really, no new changes this morning as models have continued in their persistence of this cold snap. If this verifies, modeling will have performed very well across the board in regards to temps - a nice shoulder season pick-up.

I think if we can get through Tuesday, we may(famous last words) be home free. The number of records on the table for the next few days are impressive and many - record lows and record low max temps. Even more impressive, some of the records are not low hanging fruit, meaning they are old records that have stood the test of time. Man, I am ready for summer. I usually don't say that, but this year I am. With MRX noting this could be one of the three latest freeze/frosts on record, this could be some rare air. I am with @Stovepipe, this cold weather pattern is wearing me out! LOL. It pretty much stinks. The next 5-6 days will be colder than many places above 6,000' in WY! Yes, I do follow that climate there.

From MRX.... Wednesday Night through Saturday The period commences with the first shot of colder air due to falling heights and preceding northwest flow behind a surface cold front to the southeast. With this northwest flow and potentially lingering low to mid-level moisture, some light sprinkles or flurries are possible in the east Tennessee and southwestern Virginia mountains earlier in the night. Otherwise, focus is on the degree of clearing skies and decreasing winds for low temperatures and frost potential. Even with lessened radiational cooling, anomalously negative 500mb heights and 850mb to 925mb temperatures in the 0 to +5 degrees Celsius range will support low temperatures dropping 10 to 15 degrees below average. Increasing heights and a surface high centered across the deep south will allow for a dry and clear Thursday with temperatures still noticeably below normal. This settled pattern comes ahead of a developing leeward surface low and positively tilted upper trough that advances eastward into Friday. While minor discrepancies still exist, model guidance is in agreement for the center of the surface low to track over Kentucky/Ohio River Valley during the morning and afternoon hours on Friday. With a lack in instability and climatologically average PWAT values, convection and excessive rainfall are of little concern with this system. However, a pre-frontal 850mb jet of 40 to 50 knots and a tight SW to NE pressure gradient could produce gusty winds. Following the PM frontal passage, northwest flow keeps slight chance PoPs in the TN mountains, along with bringing a steep temperature drop into Saturday morning. During this time frame, 500mb height anomalies are suggested by global ensemble means to be -15 to -20 dam with 850mb temperatures approaching -5 degrees Celsius. Per the NAEFS Ensemble Situational Awareness Table, these 850mb temperatures are near record low levels and nearly 4 standard deviations below the mean. Although cloud cover and northwest winds both linger behind the front, the very low height anomalies, 850mb temperature anomalies, and near freezing 925mb temperatures will likely support temperatures to fall into the 30s area-wide with locations outside of the Tennessee Valley near the freezing mark. Record lows for CHA and TYS are in the mid-30s with TRI`s record low at 30 degrees for May 9th, so cloud cover and winds will be key to testing these lows. The record low max temperatures, which are 57 (CHA in 1923), 55 (TYS in 1906), and 53 (TRI in 1992), will also be tested as the cold upper support and surface high pressure persists through the day. Sunday through Tuesday Saturday night heading into Sunday morning, model guidance is in agreement for the surface high to be centered just to the east of the CWA. While 850mb temperature and 500mb height anomalies both increase slightly, radiational cooling with decreased winds and cloud cover will help to drop temperatures potentially lower than the previous day with a higher likelihood of record lows being broken. The record lows for the day of May 10th with the years are as follows: CHA-(38 in 1966, 1947, and 1906), TYS-(37 in 1906), and TRI-(32 in 1966). With radiational cooling, lows dropping to upper 30s for CHA, mid 30s for TYS, and lower 30s for TRI look increasingly likely. In addition to record lows, this anomalous cold could yield one of the top 3 latest frost/freeze events on record.

MRX bringing the hammer on the afternoon disco with mentions of all of the various cold records now on record. Feel free to post the comments or I will try to later.

No change this morning regarding the upcoming cold and freeze/frost potential for this weekend. Overnight and morning global model runs did not trend warmer. For NE TN, looks like Thursday, Saturday, and Sunday mornings have a threat for frosts. Depending on which model you look at, Saturday and Sunday do have the potential for nighttime temps to dip below freezing. My point and click is already 32 for Sunday morning. The 0z Euro is trending colder(nearly ten degrees over the past several days for Sat/Sun), but is basically frost. The 6z GFS and 0z GEM are historically cold. Looks like MRX is riding with the Euro, and I don't blame them. However, I do know on recent cold mornings during April that temps were colder than forecast if the weather cleared and the winds went calm. Slim margins to work by for sure, and I don't envy that job. For now, I would say that Saturday and Sunday morning are going to be sketchy in NE TN, the northern Plateau, W NC, SW VA, SE KY. Of note, the 6z GFS is picking up on another quick shot of cold on Tuesday(that has been a common theme...the Euro has not had that one) and Friday of next week with patchy frost potential. Once we get by the freeze, my plants are going in the ground and we will just cover them at night. In other words, this pattern is repeating on the GFS. The Euro is having none of that, but it missed this weekend's cold. I think it is just shoulder season trouble which we know is common.

I have some of that on order. First year trying that type of corn. Do you like it? Probably won't get here until next week, so I am stuck planting it next week pretty much no matter what. Plus, my real fight is with raccoons later in the summer. LOL. I am probably going to have to break down and put an electric fence around the garden. Yeah, I would probably wait. It is unlikely the corn would be up by the time it frosts/freezes. However, the ground would be pretty cold and might hurt germination rates. If it isn't the cold that is a problem, it is the really wet fields. Tougher call in Knox Co. NE TN is an easier call as the cold looks likely this weekend. The problem with planting later is if the season goes really dry while it is producing corn. Tough start to a very important growing season in the SE. Keep us updated on how it does this summer!

The departures for May(comparing last year to this year only) will be impressive I think. Summer began last year during May, This year, we can't seem to shake March!

That is pretty incredible.

In their morning discussion, MRX is now warning of frost for the northern 2/3 of the valley this weekend. Saturday and Sunday look like good bets for frost. GFS also depicting a second cold shot of cold middle of next week, and then maybe that is it. My plants may go in the ground the very afternoon of the last frost. Really stretching how long they last in their containers. Cutting it close. Even for Thursday now, the 0z Euro has me at 35. Could be nearly a week with the threat of frost. The Euro has the northern half of the Plateau below freezing on Saturday AM with TRI and Knoxville with nearly the same temps 34-35. TRI again gets to 35 on Sunday AM with Knoxville in the upper 30s. The Euro does not have the second sneaky front, but the CMC and GFS do. That front is centered some time on Tuesday, and TYS seems. Of not the GEM and GFS have hard freezes in the I-81 corridor with temps 25-27 for TRI on Sunday AM. Truly remarkable to see that type of air mass which would be historical for this area. Those two models have a longer duration (meaning hours per night) event early Sunday AM. With those temps, I likely will make an effort to cover even my cool weather crops. Again, looks like several nights with the potential for frost beginning on Thursday AM and lasting to Tuesday or Wednesday of the next week. Right now, Saturday and Sunday AM look like the biggest problem with the highest probability of frost. Keep your fingers crossed that this modifies on modeling. It hasn't yet, but it still may. Otherwise, probably time to consider this as a real possibility since some of the models now have the threat under 84 hours.

Edited comment above...not low to mid 20s but low to mid 30s. Bad but not that bad!

From the MRX afternoon disco...excellent write-up BTW today. Sunday looks like the worst day, but the forecast timeframe is not there yet. Should know more tomorrow. There may even be another frost after Sunday. Thursday looks dry but then more rain on Friday as a shortwave moves across the region from out of the Central Plains/Missouri River Valley. While this is happening, another potent shortwave dives down out of Ontario and into the Ohio River Valley. This reinforces the longwave trough across our area and allows cold Canadian air to dive south into the region. This airmass will lead to max temps in the upper 50s and low 60s on Saturday and Sunday which is 10 to 15 degrees below normal. The big story is the overnight lows on Friday and Saturday night. Lows will range from near freezing across the northern areas to the low 40s across the southern TN Valley. Right now, the forecast lows for Saturday night/Sunday morning are only a few degrees off the record low temps. The records min temps for May 10th are as follows: CHA 38 in 1966, TYS 37 in 1906, TRI 32 in 1966.

No changes to yesterday's discussion regarding NE TN. Threat of a freeze and/or frost is still there. The signal for a severe(relative to season) cold snap is now growing. There are now several days which threaten at the very least frost. Models seem to be converging on temps in the low to mid 30s(edit) with all-time record lows for May still on the table.

I think in NE TN, Sunday and Monday(10th and 11th) are the times we will have to watch. The Euro again cooled. The 6z GFS again has a freeze on Sunday morning. The EPS is now quite cold. One week from Sunday, temps over night are forecast to be nearly 15-30 degrees below normal. We need to pull for the Euro as it is just patchy frost over NE TN. The GFS is a hard freeze w damaging frost reaching into northern Alabama and Georgia w Middle and East TN. The 0z GEM is in in the 6z GFS camp for Sunday AM with the freezing line reaching well south of Knoxville. Very much hoping this does not verify as the GEM and GFS show what would be an historically cold air mass on Sunday and Monday mornings(one week). That is absolutely NOT set in stone as we all know the rules about modeling this far out. Again, I know that this year gardening has a much more significant role in our society(and rightfully so)...so just trying to keep people in the know and let them make their own decisions. For those of us(stovepipe and me), we have plants that won't fair well for another week...so tough decision. The frost doesn't worry me as I can just cover plants. The potential freeze over NE TN is the concern, especially if it is 4-6 hours in duration.

Positive trend and a step in the right direction on the 18z GFS is it has removed the hard freeze...Still has plenty of frost for NE TN though. I still don't like seeing the cold trend on all modeling today. Really hoping climatology sticks a fork in those extreme solutions. Light frost we can work around. A mid-May hard freeze is nearly impossible to work around. My solution may just be adding a temporary hoop house for my tomatoes that go into the ground.

I did the same thing! I had to buy some 7" cow pots to save mine and build a hoop house. LOL. Even those are needing planted. Not sure I have 10 more days, but TRI looks nasty for next weekend. If I was in Knoxville, my decision would probably be different. Right now, I have to decide if I can get ten more days out of those plants in containers. Maybe. I have some great looking potatoes already in the ground. I hate to see those get set back. They will come back if frozen, but hate to see them get burned. I may build a hoop house over those. Nothing fancy. Just PVC, rebar, and plastic. Let's hope this modifies!!!!!

A blend of the 12z Euro, GEM, and the GFS still results in all-time record lows(for May) being challenged next weekend in some areas. Fingers crossed for moderation.

I should add that Knoxville is borderline on the Euro, but folks down there will need to keep an eye out. I will assume the GFS is a cold outlier, but even the warmer models are trouble if they cool just a tad more for the Central Valley. NE TN, SW VA, SE KY, the Plateau, and W NC need to really keep a close eye on the situation. Middle TN is not out of the woods either. This is a really pain in the neck BTW. I take no joy in discussing this whatsoever. None. Just discussing this as a courtesy. Seeds are tough to find right now as are some plants. Don't want to waste them.

Yeah, that caught my attention. I was going to plant this weekend...now I am heading to Lowe's to find the material for about 40' of temporary hoop house. That will be tricky as I won't put the plastic on while we have these hot temps. I will wait until ~Thursday and put the plastic on, but get the hoops in place this weekend. The airmass being shown on the Euro is 10-20 degrees below normal. I guess this is what happens when the PV wraps up to record levels and doesn't release cold on time! LOL - well not really laughing. Let's hope and pray that look modifies as it would be absolutely devastating to regional farmers in NE TN and W NC with strawberries already fruited. The plants will be fine, but the berries would potentially be burned with temps that low. Need to catch a break on this one. I have plants ready to go in this weekend. Going to have to coax them along for another ten days or so. Hate to be making decision based on a model 7-8 days out, but TR and FR are no gimme right now.

The 12z Euro OP had cooled by 5-6 degrees on Sunday(the 10th) and is nearly 15 degrees cooler for the night before. In NE TN they have gone from lows in the 50s on Saturday night(9th) to lows in the upper 30s in NE TN. Essentially, we went from no threat whatsoever in NE TN to patchy frost on Saturday and Sunday evenings next weekend. It didn't cave, but that was a massive bend.

The GEM has lows the following Monday in the mid 20s for NE TN. Areas of Knox Co would be in the 20s as well with downtown in the mid 30s. Anyway, plenty of time for that to change as that is out there in time. Just a heads up. Very bizarre to see two models now showing what would be a record setting event on consecutive nights. Let's hope the Euro holds. Update to follow later this afternoon.

I hear you. I am just across the mountain from you in TRI, and I feel your pain. That is a really ugly look next weekend. I have a small hoop house. May have to rig up a heater if those temps verify. Can you imagine the tree foliage with long duration temps in the 20s(teens at higher elevation)? GEM has temps fairly cold as well now - trended colder this run. Those are all time record lows(for the month of May) being challenged on both of those models for TRI.

Before hitting the panic button, it is going to have to have some support from other modeling at 12z before I believe it. We have been here many times with the GFS. It just gives me incredible pause as sometimes it can get lucky. Will update later after the Euro. So far, the Canadian is not remotely that cold. If I gamble(and set plants out) and it is right, we would lose months of hard work getting plants ready. OTH, if I wait, plants won't start producing fruit until prim blight times. Edit: The GEM is nearly 15 degrees colder than its previous run. Temps in the mid 30s for Sunday(the 10th) morning so far in NE TN...and not done dropping yet. Even those temps would begin to challenge all-time record lows. Update: Dang, the 12z GEM has temps in the low 30s over NE TN. 31 IMBY on that run. That would be several hours at our below freezing in NE TN. If the Euro folks like the GEM, I am going to hold off putting anything else in the ground.