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Post by jeepers on Dec 25, 2023 22:30:11 GMT -6
Merry Christmas, everyone! 🎄🎄
A few flakes this week would be nice.
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Post by Snowstorm920 on Dec 26, 2023 0:33:43 GMT -6
Euro QPF is juicy. There has been a definite trend in a slower, stronger upper low that even shows signs of stopping and pivoting over the area.  |
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Post by Lovableweatherguy TROY,MO on Dec 26, 2023 0:59:02 GMT -6
Euro QPF is juicy. There has been a definite trend in a slower, stronger upper low that even shows signs of stopping and pivoting over the area. Me likey |
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Post by Chris Higgins on Dec 26, 2023 8:41:43 GMT -6
The chances for some mood snow continue to look good for tomorrow. And if it were 5-8 degrees colder I'd say several inches are possible. But the very marginal surface temperatures continue to keep me thinking that accumulations will be hard to come by despite some nifty looking model eye candy. A better tool in this case will be snow depth change... and across the board those look much more realistic! Where some of the model snowFALL graphics show 3-5 inches... all of the snow depth change graphics are less than 1 inch for the most part and even in those cases... very splotchy looking. All of this signals a real difficulty getting snow to stick... especially during the daylight hours. I still like the idea of a slushy dusting/coating on grassy surfaces... with roads staying mostly wet. If it does snow heavy enough in any one spot, a brief light slushing of some roads may occurr... but with rapid improvement as precip intensity declines.
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Post by Snowman99 on Dec 26, 2023 8:45:37 GMT -6
Thinking later Thursday and thursday night looks more interesting
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Post by Chris Higgins on Dec 26, 2023 8:59:44 GMT -6
Thinking later Thursday and thursday night looks more interesting That is an interesting feature... looks lime a surge of warm air advection aloft /new trowal that rapidly wraps around the northwest side of the departing upper low. |
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Post by BRTNWXMAN on Dec 26, 2023 9:07:45 GMT -6
Models are making a pretty good case for a relatively narrow zone of minor accumulations somewhere close to or in the Metro Wed into Thurs. Most of the precip falls with 1000-850mb THKN <130dm although surface temps are definitely borderline. That pivot and slower exit of the low is an interesting trend, with some models suggesting snow lasting into Friday now. Could be a pretty wintry stretch coming up...a nice change of pace.
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Post by rb1108 on Dec 26, 2023 9:26:38 GMT -6
NWS seems to think there is a slight chance that prep rates could overcome temps, which if occurred, could lead to several inches of wet snow. But with our luck around here, we know how unlikely this scenario is to actually happen.
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Post by BRTNWXMAN on Dec 26, 2023 9:31:04 GMT -6
NWS seems to think there is a slight chance that prep rates could overcome temps, which if occurred, could lead to several inches of wet snow. But with our luck around here, we know how unlikely this scenario is to actually happen. It's always smart to be pessimistic with borderline setups around here...but there does seem to be potential for some wet snow accumulations with this. Could be some very pretty scenery with it sticking to the trees and grass. Or it could be another beautiful 36* rain, lol. |
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Post by Chris Higgins on Dec 26, 2023 9:38:23 GMT -6
NWS seems to think there is a slight chance that prep rates could overcome temps, which if occurred, could lead to several inches of wet snow. But with our luck around here, we know how unlikely this scenario is to actually happen. It's always smart to be pessimistic with borderline setups around here...but there does seem to be potential for some wet snow accumulations with this. Could be some very pretty scenery with it sticking to the trees and grass. Or it could be another beautiful 36* rain, lol. This is the kind of situation where elevation and the urban heat island can make a big difference as well. We have seen in the past where there's almost no accumulation inside 270/255 loop. But then you get just outside and the snow sticks a little more readily. Same thing as you move west and southwest up into the ozark plateau. |
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Post by dschreib on Dec 26, 2023 9:42:16 GMT -6
This was the first year I ever remember seeing mosquitoes on Xmas eve. I saw a few bugs flying around when I was out yesterday. Very unusual for sure. I had a honey bee flying around me while I was putting lights up on Saturday. |
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Post by Snowman99 on Dec 26, 2023 9:52:24 GMT -6
Looking at things on the morning runs. Def think Thursday night is the bigger deal
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giarC71
Wishcaster
Posts: 220 
Snowfall Events: Blizzard of'82 I became addicted to weather
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Post by giarC71 on Dec 26, 2023 10:35:34 GMT -6
We all know with borderline temps that accumulating snow typically doesn't win out and it's minor if anything at all. You won't be disappointed with this mindset. As it gets closer we can adjust but this isn't a big deal, other than for the weather enthusiasts. When was the last time marginal temps got several inches of snow?
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Post by ndolan387 on Dec 26, 2023 11:00:25 GMT -6
Some thoughts (some of which aren't all correct):
***12-27-23 to 12-29-23 Low Impact Deep Cyclonic Rain/Snow Two Part System***
***Watch for Changes in the Coming Hrs/Days***
Do not expect big snow accumulations. This system is just a setup down toward a vibe that feels more like winter. Part 1 will be weaker and less impressive than the wildcard Part 2. Haha, I just contradicted myself. Elevation will play a role in it. The warm air advection could be more impressive than expected, leading to more rain than snow with Part 1. IF Part 2 pans out then it will be the meat and potatoes of our potential heaving dusting (maybe 1”+).
The atmosphere finally wants to play some winter minor league ball for the middle part of the country especially the St. Louis Metro. It’s been a lackluster start to winter thus far. The theme in recent years is for a backloaded winter. The majority of our winter precipitation falls in late Jan, Feb, and March.
All eyes on our system (Part 1) of interest currently over the Northern Central U.S. Starting upstairs at 250 mb, there’s a screaming jet streak to our south reaching 170 to 180 kts. We happen to be on the northern side of this jet streak. As area of low pressure slides to the east, we end up on the left exit region of this jet. So there’s upper level divergence. In layman terms, the vector length of wind direction is increasing as well as spreading air out.
Looking at 500mb (50,000ish ft up in atmosphere), the features include a deep neutral cyclonic shortwave trough stretching from just west of the 4 corners region east all the way into the Ohio Valley. Deep positive cyclonic vorticity is focused across the middle of country and then the STL neck of the woods as this shortwave trough spins our way late Tuesday into Wednesday. What’s interesting about this system is the initial wave spin of energy early Wed may not be the full story. The shortwave does reach maximum strength in terms of vorticity late Tuesday just to our west. So we have our lift. As well, we have warm air advection out ahead with Part 1 so that’s another lifting mechanism. The air feels cold, but it’s relatively warmer upstairs in the sky.
The area of low pressure starts out in the Nebraska area today and slides our way later in the week. Part 1 features a weaker low. It’s a 1000+ mb surface low so it's weak sauce. If Part 2 delivers, the upper level low could become stronger as the TROWAL becomes an influence.
The true wildcard with this system is the TROWAL (Part 2) that tries to set up late Wednesday into Thursday/Friday. Timing on this is still iffy. With borderline temps elevation will play a role in if some areas see snow or rain. The area of low pressure is trying to reach max strength somewhere near our area. Whenever and wherever it closes off, will then determine what part of Missouri will see more or less rain/snow. As well, how long the snow wants to last. Location and timing of this trough of warm air aloft will determine if we do get a heavy dusting of snow (maybe more). Some more cake and icing on the cake (i.e. wrap around cyclonic driven snow). This would be in the later Wednesday to Thursday timeframe. Expect changes in the time of this Part 2 wildcard feature.
This system has to generate its own moisture profile as the Gulf of Mexico looks to be mainly closed off. As well, PWAT values seem very low so in terms of moisture this system is not impressive in terms of amounts. The initial waves with Part 1 do have an influence from some warm air advection. Warm lol…it still feels cold after all this warm wet weather we’ve seen. Warm relatively speaking. Out ahead of the system today winds will be gusting out of the South. Before the wet snow spreads into the area, winds will shift toward the SE. The cold air advection part of the system is (Part 2) when winds switch to the NNW.
One of the last important pieces to the puzzle is the temperature profile. In addition to generating its own moisture supply, this system will also have to produce its own cold air supply. A very borderline setup. The one thing we do have going for us when looking upstairs in the atmosphere down to the surface, there’s no pesky warm wedge creating a headache with precipitation type. It will either be rain or snow. None of that yucky freezing rain or sleet haha.
It’s important to stress that timing and details of when the system decides to close off and develop a TROWAL late Wednesday into Thursday will affect the potential strength of this cyclonic piece of energy. As well, determine if we do get more a heavy dusting (more than 1” of wet snow accumulation). The models will start to hone in on the more accurate solutions later today.
Timing:
Part 1:
After 3am till midday Wed (12-27-23)
Rain or snow could break out as early as Wed morning after 3am across the area from west to east. The recent short range model (HRRR) is showing it breaking out as rain. Temps will be above freezing so anything that falls (rain or snow) won’t stick. I can’t rule out it sticking to the grass or elevated surfaces if it does want to snow. This is going to be a mood wet snow and it won’t cause any issues for drivers Wed morning.
Break then
Part 2:
Late Wed or early Thursday start time. Lasting potentially into early Friday. (12-27-23 to 12-29-23). Timing is going to change.
Look for a little break in the precipitation as it warms up later Wed. Part 2 with the TROWAL if it happens will begin any time during the day Thursday. This will most likely start out as rain, but as the sun sets look for a transition to snow late Thursday into Friday as the system starts to wrap up and we lose solar insolation. Winds will begin to increase out of the northwest as it generates is own source of cold air. As we get closer, Part 2 will be become more clear.
Amounts:
Expect some rain with this system and potentially expect some wet snow.
Mainly rain with Part 1 maybe a dusting of snow on the grass or elevated surfaces with part 1.
Depending on how much energy is associated with part 2, we could get an additional heavy dusting, dare I say more (1”+)!
We are starting to get back to more seasonal temperatures and the white stuff is trying to fall from the sky. Another tid bit of information is if the mysterious Lambert Airport receives at least a trace of snow it will be latest trace of snow of any winter season ever recorded since 1900. Though Lambert was at a different location than its location now in 1900; that’s important to note! Enjoy this little set down into winter. A more colder and wintry pattern looks more likely during the first week of January. Too far out to get fancy!
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Post by Chris Higgins on Dec 26, 2023 11:53:41 GMT -6
This series of events definitely has mood snow written all over it.
The ground may briefly start to turn white on the grass tomorrow during the heavier bursts... but when the precip intensity starts to back off it's likely to all melt almost as fast as it fell. There is a slightly better chance for precip intensity to overcome the very very marginal temperatures tomorrow night with a little better staying power to anything that sticks on the grass. So I wouldn't be suprised to see a sloppy white coating on grass and elevated surfaces by sunrise Thursday...especially away from the 270/255 loop and up in the hills of southeast Missouri. Anything from Wednesday night will melt Thursday morning as we wait for the new player... the rather robust looking TROWAL that rotates southwest into the region Thursday evening/night. This may be widespread and steady enough...and come in with slightly colder air (at least at the onset) to be mainly wet snow. I wouldn't be suprised to see a few 1-2 inch totals at max intensity with this band...somewhere in the viewing area. However, tracing the temperature profiles in the low levels shows some respectable low level warm air advection from the northeast late Thursday night into Friday morning, so I would expect the wet snow to change back to rain late thursday night or Friday morning. Any accumulating snow we get Thursday night will also melt quickly Friday morning.
All and all a really sloppy, somewhat unusual systems...especially for this time of year. This is more like a November or March system... not late December. But welcome to 2023!
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Post by Chris Higgins on Dec 26, 2023 11:54:10 GMT -6
Some thoughts (some of which aren't all correct): ***12-27-23 to 12-29-23 Low Impact Deep Cyclonic Rain/Snow System Two Part System*** ***Watch for Changes in the Coming Hrs/Days*** Do not expect big snow accumulations. This system is just a setup down toward a vibe that feels more like winter. Part 1 will be weaker and less impressive than the wildcard Part 2. Elevation will play a role in it. Haha, I just contradicted myself. The warm air advection could be more impressive than expected, leading to more rain than snow with Part 1. IF Part 2 pans out then it will be the meat and potatoes of our potential heaving dusting (maybe 1”+). The atmosphere finally wants to play some winter minor league ball for the middle part of the country especially the St. Louis Metro. It’s been a lackluster start to winter thus far. The theme in recent years is for a backloaded winter. The majority of our winter precipitation falls in late Jan, Feb, and March. All eyes on our system (Part 1) of interest currently over the Northern Central U.S. Starting upstairs at 250 mb, there’s a screaming jet streak to our south reaching 170 to 180 kts. We happen to be on the northern side of this jet streak. As area of low pressure slides to the east, we end up on the left exit region of this jet. So there’s upper level divergence. In layman terms, the vector length of wind direction is increasing as well as spreading air out. Looking at 500mb (50,000ish ft up in atmosphere), the features include a deep neutral cyclonic shortwave trough stretching from just west of the 4 corners region east all the way into the Ohio Valley. Deep positive cyclonic vorticity is focused across the middle of country and then the STL neck of the woods as this shortwave trough spins our way late Tuesday into Wednesday. What’s interesting about this system is the initial wave spin of energy early Wed may not be the full story. The shortwave does reach maximum strength in terms of vorticity late Tuesday just to our west. So we have our lift. As well, we have warm air advection out ahead with Part 1 so that’s another lifting mechanism. The air feels cold, but it’s relatively warmer in upstairs in the sky. The area of low pressure starts out in the Nebraska area today and slides our way later in the week. Part 1 features a weaker low. It’s a 1000+ mb surface low so its weak sauce. If Part 2 delivers, the upper level low could become stronger as the TROWAL becomes an influence. The true wildcard with this system is the TROWAL (Part 2) that tries to set up late Wednesday into Thursday/Friday. Timing on this is still iffy. With borderline temps elevation will play a role if some areas see snow or rain. The area of low pressure is trying to reach max strength somewhere near our area. Whenever and wherever it closes off, will then determine what part of Missouri will seem more or less rain/snow. As well, how long the snow wants to last. Location and timing of this trough of warm air aloft will have will determine if we do get a heavy dusting of snow (maybe more). Some more cake and icing on the cake (i.e. wrap around cyclonic driven snow). This would be in the later Wednesday to Thursday timeframe. Expect changes in this time of this Part 2 wildcard feature. This system has to generate its own moisture profile as the Gulf of Mexico looks to be mainly closed off. As well, PWAT values seem very low so in terms of moisture this system is not impressive in terms of amounts. The initial waves with Part 1 do have an influence from some warm air advection. Warm lol…it still feels cold after all this warm wet weather we’ve seen. Warm relatively speaking. Out ahead of the system today winds will be gusting out of the South. Before the wet snow spreads into the area, winds will shift toward the SE. The cold air advection part of the system is (Part 2) when winds switch to the NNW. One of the last important pieces to the puzzle is the temperature profile. In addition to generating its own moisture supply, this system will also have to produce its own cold air supply. A very borderline setup. The one thing we do have going for us when looking upstairs in the atmosphere down to the surface, there’s no pesky warm wedge creating a headache with precipitation type. It will either be rain or snow. None of that yucky freezing rain or sleet haha. It’s important to stress that timing and details of when the system decides to close off and develop a TROWAL late Wednesday into Thursday will affect the potential strength of this cyclonic piece of energy. As well, determine if we do get more a heavy dusting (more than 1” of wet snow accumulation). The models will start to hone in on the more accurate solutions later today. Timing: Part 1: After 3am till midday Wed (12-27-23) Rain or snow could break out as early as Wed morning after 3am across the area from west to east. The recent short range model (HRRR) is showing it breaking out as rain. Temps will be above freezing so anything that falls (rain or snow) won’t stick. I can’t rule out it sticking to the grass or elevated surfaces if it does want to snow. This is going to be a mood wet snow and it won’t cause any issues for drivers Wed morning. Break then Part 2: Late Wed or early Thursday start time. Lasting potentially into early Friday. (12-27-23 to 12-29-23). Timing is going to change. Look for a little break in the precipitation as it warms up later Wed. Part 2 with the TROWAL if it happens will begin any time during the day Thursday. This will most likely start out as rain, but as the sun sets look for a transition to snow late Thursday into Friday as the system starts to wrap up and we lose solar insolation. Winds will begin to increase out of the northwest as it generates is own source of cold air. As we get closer, Part 2 will be become more clear. Amounts: Expect some rain with this system and potentially expect some wet snow. Mainly rain with Part 1 maybe a dusting of snow on the grass or elevated surfaces with part 1. Depending on how much energy is associated with part 2, we could get an additional heavy dusting, dare I say more (1”+)! We are starting to get back to more seasonal temperatures and the white stuff is trying to fall from the sky. Another tid bit of information is if the mysterious Lambert Airport receives at least a trace of snow it will be latest trace of snow of any winter season ever recorded since 1900. Though Lambert was at a different location than its location now in 1900, that’s important to note! Enjoy this little set down into winter. A more colder and wintry pattern looks more likely during the first week of January. Too far out to get fancy! Nice write-up Nick! Keep it coming! |
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Post by bellevillewxguy on Dec 26, 2023 12:48:45 GMT -6
Dave has unleashed the 'H' word for snowflake size Wednesday and possibly Thursday in his latest FB message/post.
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Post by WEAXWATCHER on Dec 26, 2023 12:49:00 GMT -6
What is the timing of the snow down 44? I had planned to stop on OKC for the night, but wondering if I should drive through and get home around midnight
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Post by Snowstorm920 on Dec 26, 2023 13:04:11 GMT -6
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Post by Worldserieschampions (Chicago) on Dec 26, 2023 13:10:53 GMT -6
12z euro is getting that “loaded gun” look to it by day 10 with extreme cold building in the north and a major area of low pressure in the southwest.
Things are finally getting more interesting.
A SSW is also on the table.
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Post by WEAXWATCHER on Dec 26, 2023 13:20:20 GMT -6
Soooooo... drive through the night... because 44 is a PITA with any snow at all.
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Post by BRTNWXMAN on Dec 26, 2023 13:32:51 GMT -6
That looks about right...lol |
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Post by kcwxdude on Dec 26, 2023 19:26:11 GMT -6
Alright, you guys tempted me to brush off my old Air Force weather forecasting skills and do a little digging in to the models here. It’s very easy to get caught up in the lift and moisture available, but forget to check the actual & forecasted surface temps. I agree, this system sort of digs and rotates right in the region of STL even just slightly SE, but the main axis of accumulations would paint a swath west to northwest of STL based off the data I’ve seen. BUT, and I mean this nicely, it’s not cold enough to produce any significant event! I haven’t had a chance to look at the newest data out there, however it was 60+ degrees in the last 24-48 hours, and a major snow accumulation is basically a wish at this point in time. This has mood flakes written all over it. If you live in southeast central Missouri, in an elevated position, you’re looking at about 1” accumulation before daylight sublimates it(at best), other wise this has a dusting at best written all over it in the metro/heat island area.
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Post by ndolan387 on Dec 26, 2023 19:38:38 GMT -6
Update:
***Update: 12-27-23 to 12-29-23 Low Impact Deep Cyclonic Rain/Snow System Two Part System***
Part 1:
Start Time: Rain will spread west to east after 12am tonight.
Amounts: a dusting west of STL metro (near the middle part of the state). STL metro no accumulation. Looking more and more like rain with Part 1 for the STL metro. Starting as rain once again after midnight tonight. HRRR looks awfully wet, warm at first. HRRR has a wet bias, using a blend of other models I'd say the precipitation is going to be light for a lot of Part 1 (maybe moderate at times). Pretty bad that we can't even get snow in the middle of the night on Dec 26-27th. If the precipitation rate increases look for the rain to switch to a wet snow before sunrise tomorrow for the STL metro. This is a not a uniform socialistic precipitation pattern. There are going to different mesoscale bands. Just west of the STL metro all the way to central MO looks like the prime zone for heavier rain/snow. So it will be switching on and off between rain and snow. It's a slop fest! Winds out of the SE.
Part 2:
Start Time: Timing is still iffy. Late Wed/After 12am Thursday.
Amounts: a heavy dusting...potentially 1"+ where the best mesoscale bands set up. Right now the zone between Jeff City and Warrenton is the jack spot zone for heavier amounts. A higher chance of 1-2". There should be a break from the mesoscale bands Wed evening/night before Part 2 comes early Thurs. morning (after 12am Thurs.). Part 2 is no longer a wild card. We are within the famous 48 hr to add some true confidence to the forecast. Part 2 is the meat of potatoes of this deep cyclonic 2 part rain/snow system!
The position and location of the TROWAL will determine where the strongest mesoscale bands set up. The temps look less borderline and colder (than Part 1) as this piece of cyclonic energy generates its own cold air supply. More moisture, higher snow/rain rates mean that the wet snow will have a better chance sticking to elevated surfaces and the grass before sunrise Thurs. The speed of this TROWAL is still up for debate. The slower and the deeper the cyclonic is, will determine if the STL metro sees a heavy dusting or dare I say 1"+ wet snow sometime Thursday.
Expect more changes in the start time of Part 1 and 2 and the speed, location of the mesoscale bands of rain and snow. Enjoy this mood snow! This system is a reminder that it's winter after all even though it's not impressive!


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Post by amstilost on Dec 26, 2023 19:44:54 GMT -6
ndolan357
I really enjoyed that write-up. Made me think I was reading an NWS Discussion.
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Post by Snowstorm920 on Dec 26, 2023 19:46:17 GMT -6
I foresee some dramatic haves and have nots with this system.
Someplace might pick up 2-3” and a few miles down the road may have seen a handful of flakes total
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Post by kcwxdude on Dec 26, 2023 20:02:38 GMT -6
I foresee some dramatic haves and have nots with this system. Someplace might pick up 2-3” and a few miles down the road may have seen a handful of flakes total I’ll be surprised to see accumulations that high, and if it does happen it will be outliers in elevated areas west and southwest of the STL metro. |
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Post by ndolan387 on Dec 26, 2023 20:23:37 GMT -6
I foresee some dramatic haves and have nots with this system. Someplace might pick up 2-3” and a few miles down the road may have seen a handful of flakes total I’ll be surprised to see accumulations that high, and if it does happen it will be outliers in elevated areas west and southwest of the STL metro. Yep elevation is higher the further west you go. The westerners could be the "winners" lol with maybe 2"+ lollipops. |
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Post by Worldserieschampions (Chicago) on Dec 26, 2023 20:34:34 GMT -6
I foresee some dramatic haves and have nots with this system. Someplace might pick up 2-3” and a few miles down the road may have seen a handful of flakes total I’ll be surprised to see accumulations that high, and if it does happen it will be outliers in elevated areas west and southwest of the STL metro. Thursday night could drop that much somewhere in the region. 00z nam is favoring Central Illinois but the area will bounce around the next couple runs. |
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Post by Snowman99 on Dec 26, 2023 20:47:21 GMT -6
Thursday evening and night, a pretty good size chunk of the area could see over an inch with 2+ in several places IMO.
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