Wx 24/7 Posted December 5, 2018 Share Posted December 5, 2018 There is more than enough in that graphic to prompt TSA to issue a Winter Storm Watch. Wonder if they are waiting to analyze the 00z data first? Link to comment Share on other sites More sharing options...
OUGrad05 Posted December 5, 2018 Share Posted December 5, 2018 Just now, Wx 24/7 said: There is more than enough in that graphic to prompt TSA to issue a Winter Storm Watch. Wonder if they are waiting to analyze the 00z data first? That would be my guess especially with the GFS still being "meh" Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 5, 2018 Share Posted December 5, 2018 1 minute ago, Wx 24/7 said: There is more than enough in that graphic to prompt TSA to issue a Winter Storm Watch. Wonder if they are waiting to analyze the 00z data first? Their discussion below. No mention yet but I would bet you're right. A rea Forecast Discussion National Weather Service Tulsa OK 322 PM CST Wed Dec 5 2018 .DISCUSSION... The big story continues to be the potential for wintry weather Friday into Saturday. Winter weather headlines will likely be needed as impactful weather is expected across portions of eastern Oklahoma and western Arkansas. A cold front is slated to move through eastern Oklahoma and western Arkansas on Thursday with the potential for rain in the vicinity of the boundary as it moves through the area. Temperatures will be noticeably cooler on Thursday behind the cold front. The precipitation shield will begin to return to the north on Friday as isentropic lift increases north of the frontal boundary as it continues to sag south toward the northern Gulf of Mexico. Some of the precipitation along the north edge of the precipitation shield may fall as a wintry mix of freezing drizzle and light snow Friday. The potential for wintry weather really ramps up later Friday night into Saturday as an upper level moves out of the Southwest United States and across the Southern Plains. With this forecast Package went with slightly colder surface temperatures than the blended model guidance provided and an even blend of the GFS,NAM12 and ECMWF thermal profiles. Stayed fairly close to the WPC QPF with a small increase Saturday Night as a nod to the slower moving ECMWF. A wintry mix will transition to mostly all snow across the majority of the area by Saturday Evening as the cold air deepens before ending Sunday Morning. Of course, it is still early to give any real specific amounts of snow and ice. However, it is looking more likely that there will be impactful amounts of snow and ice across much of northeast Oklahoma and northwest Arkansas Friday Night into Saturday. It all depends on the ultimate track and strength of the upper level as it moves across the Southern Plains. As we move into next week high pressure will build at the surface and aloft resulting in a slow warming trend across the region. Link to comment Share on other sites More sharing options...
ouamber Posted December 5, 2018 Share Posted December 5, 2018 So are we throwing out the NAM all together? I've been throwing the GFS out! Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 5, 2018 Share Posted December 5, 2018 OUN Discussion: Area Forecast Discussion National Weather Service Norman OK 405 PM CST Wed Dec 5 2018 .DISCUSSION... We have high confidence in impactful winter weather across the forecast area. The main changes were 1) to confined to precipitation chances to southern portions of the area through early Friday morning, and limited probabilities across northern Oklahoma until late Friday/Friday night, 2) to make minor adjustments to ice accumulations and amounts, 3) increase snow amounts across portions of western and northern Oklahoma, 4) increase precipitation probabilities, and 5) significantly lowered post-event temperatures Sunday into Monday given expected snow cover. Low level saturation near/behind the cold front tomorrow doesn't appear to be sufficient for drizzle or freezing drizzle but we'll need to watch the trends in the observations. Further south, deeper moisture and a more pronounced near-surface saturated layer below capping warm/dry layer may yield some drizzle. Temperatures there will be warm enough for no freezing concerns. For post-frontal temperatures through Friday we went with the low end of model guidance (NAM, WRF-ARW) which seems most reasonable given the pattern and character of upstream cold/dry cP air mass. Models are in fairly good agreement with synoptic scale features. A closed mid-upper low will move across the Southwest tomorrow night and Friday and through the southern Plains Saturday. Large scale ascent and deepening moisture will eventually lead to light precipitation across the area, but it's onset, amounts, and resultant impacts from icing are probably the most uncertain part of the forecast at this point. There will be a west-southwest to east- northeast corridor of potentially impactful icing, including the possibility of tree and powerline damage as well as travel problems. This would be commensurate with icing amounts that approach or exceed 0.25 inches Friday and Friday night, and appears to be most likely across southwest Oklahoma extending up near and south of the I-44 corridor. We may need to adjust the highest chance of freezing rain further south from current graphics based on the latest model forecast soundings which show a deeper cold layer across the northern half of the area supporting just light freezing drizzle, and eventually sleet once dendrite probabilities increase through saturation <-12C. It's also worth noting that our cold NAM/ARW hourly temperatures may not be cold enough and at least low-end icing event may evolve further south than earlier thought, to around the Red River and into western north Texas. Where freezing rain does occur, accretion should be tempered by latent heat release where temperatures are at or just below freezing. But, 10-15 knot northeasterly winds may help offset that some. So fairly optimal ice-to-liquid ratio according to the FRAM model could develop. Again, potential rainfall amounts will need to be monitored closely. Fortunately, this is not expected to be the most optimal scenario for significant icing which would occur with colder temperatures and higher QPF amounts. We trended more aggressive with sleet potential given strengthening warm nose aloft and it's possible that sleet could at least briefly be the dominate precipitation type in a band from southwest/west- central Oklahoma eastward along and either side of the I-40 corridor, especially Friday evening and overnight. Saturday morning, as the closed low passes to our south cooling aloft will support all snow. There are some model differences by then with regards to the degree at which the low becomes closed. However, ECMWF matches well with its ensemble mean counterpart, and the spread in GEFS members is minimal for this time range as well. Deterministic GFS matches this reasonably well, and the GFS-FV3 is slightly more closed off/anomalous. All this is to say that although some slowing or slight variations in track could alter ptype placement and amounts, overall confidence is fairly high given that the peak of the event is about 3 days out. The aforementioned described synoptic setup is favorable for development of a pronounced TROWAL and deformation snow event as the deep low passes south and southeast of the area. One potential limiting factor for more robust snowfall amounts could be mixing of sleet given currently depicted thermal profiles, but current thinking is that models could be too aggressive with this and a longer duration of moderate to heavy snow could form across portions of the area. 2-4 inch snowfall amounts should be common across much of the area (especially the northwest half), and there could be a band of 6+ inches given impressive QPF amounts that have been consistent in models. We lowered temperatures after the system departs given likely snow cover. BRB/PW 1 Link to comment Share on other sites More sharing options...
StormChazer Posted December 5, 2018 Share Posted December 5, 2018 Pretty surprised Tulsa hasn't issued the watch yet....and this evening's NAM run is going to be a very important one as it'll have more information to go off of. Link to comment Share on other sites More sharing options...
JMT417 Posted December 5, 2018 Share Posted December 5, 2018 20 minutes ago, StormChazer said: Where did you find this??? It is on their hazards page Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 5, 2018 Share Posted December 5, 2018 2 minutes ago, StormChazer said: Pretty surprised Tulsa hasn't issued the watch yet....and this evening's NAM run is going to be a very important one as it'll have more information to go off of. CH 9 in OKC has 4-8 inches from SW OK through NE OK. Width covers virtually all of NE OK. along with .25 of ice in the same area. Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 5, 2018 Share Posted December 5, 2018 25 minutes ago, StormChazer said: Where did you find this??? Mine is a screenshot from the YouTube update. https://www.youtube.com/watch?v=HwsMs_4m1BI Link to comment Share on other sites More sharing options...
ouamber Posted December 5, 2018 Share Posted December 5, 2018 13 minutes ago, Weatherdemon said: CH 9 in OKC has 4-8 inches from SW OK through NE OK. Width covers virtually all of NE OK. along with .25 of ice in the same area. Where's Mike Morgan to get the hype train started? Channel 4 will no doubt have some high amounts! I live in Tulsa, but that guy is fun to watch when I'm in OKC! Link to comment Share on other sites More sharing options...
OUGrad05 Posted December 5, 2018 Share Posted December 5, 2018 9 minutes ago, ouamber said: Where's Mike Mitchell to get the hype train started? Channel 4 will no doubt have some high amounts! I live in Tulsa, but that guy is fun to watch when I'm in OKC! You mean Mike Morgan? Link to comment Share on other sites More sharing options...
ouamber Posted December 5, 2018 Share Posted December 5, 2018 Just now, OUGrad05 said: You mean Mike Morgan? Yes, that GUY! LOL Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 5, 2018 Share Posted December 5, 2018 3-6 seems to be the generally accepted amounts for Tulsa at this time. Link to comment Share on other sites More sharing options...
Will (little rock) Posted December 6, 2018 Share Posted December 6, 2018 Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 6, 2018 Share Posted December 6, 2018 Damon Lane calling for 3-6 across the expected areas and 6-12 for parts of western OK almost to Enid and Stillwater. OKC metro in the 3-6. Link to comment Share on other sites More sharing options...
JoMo Posted December 6, 2018 Author Share Posted December 6, 2018 So, NCEP is having data issues? Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 6, 2018 Share Posted December 6, 2018 3 minutes ago, JoMo said: So, NCEP is having data issues? Don't know but, the NAM just kicked off Link to comment Share on other sites More sharing options...
OUGrad05 Posted December 6, 2018 Share Posted December 6, 2018 I expected NWS to have a winter storm watch up in Tulsa but they don't yet. Must be hanging on for the 00Z data. Link to comment Share on other sites More sharing options...
Wx 24/7 Posted December 6, 2018 Share Posted December 6, 2018 1 minute ago, OUGrad05 said: I expected NWS to have a winter storm watch up in Tulsa but they don't yet. Must be hanging on for the 00Z data. Especially since your threshold for a watch is 4". Link to comment Share on other sites More sharing options...
OUGrad05 Posted December 6, 2018 Share Posted December 6, 2018 2 minutes ago, Wx 24/7 said: Especially since your threshold for a watch is 4". With GFS lingering at 1 inch that may have the hesitating. There's still some variables to work out on this thing. Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 6, 2018 Share Posted December 6, 2018 Wow. NAM still not backing off. Link to comment Share on other sites More sharing options...
WhiteoutWX Posted December 6, 2018 Share Posted December 6, 2018 This storm may have started out looking like an ice event days ago, but I think the true story will be heavy deformation snows on the backside of the system. NAM is painting quite the potent band, and while it's temperature are marginal verbatim, just looking at the synoptic features and applying conceptual models, it will be a heavy, wet pastejob of a snowstorm for someone over western OK, possibly extending into northern/central OK depending on the track. This would likely continue on east from there. I think the GFS is total trash at this point. NAM and Euro all the way. But JMHO... Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 6, 2018 Share Posted December 6, 2018 Link to comment Share on other sites More sharing options...
MUWX Posted December 6, 2018 Share Posted December 6, 2018 I think it's going to be really depressing to watch this one from the republic/Springfield area. Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 6, 2018 Share Posted December 6, 2018 Tulsa NWS needing more data before issuing watch. Area Forecast Discussion National Weather Service Tulsa OK 933 PM CST Wed Dec 5 2018 ...UPDATE... .DISCUSSION... A rather wide range of temperatures was observed this evening, with low dewpoints/light winds allowing a few spots to quickly fall below forecast lows already. Have generally lowered temps across most of the area the remainder of the night, although increasing clouds should keep lows from completely bottoming out. Quick look at the 00Z NAM doesn't clear up the winter weather potential, as it maintains a band of significant snow/sleet northwest of I-44 with a secondary max across parts of northwest AR. NAM has been consistent with previous runs but also a significant outlier as far as amounts go. A winter storm watch will likely be needed, but don't have the confidence yet to put one out without seeing more 00Z data/model runs Link to comment Share on other sites More sharing options...
JoMo Posted December 6, 2018 Author Share Posted December 6, 2018 6 minutes ago, MUWX said: I think it's going to be really depressing to watch this one from the republic/Springfield area. Maybe, storm won't be fully sampled until tomorrow and any big changes in modeling will probably happen at that point. I remember, many years ago, a snowstorm that was supposed to impact the Springfield CWA. They had warnings up, the models had been indicating heavy snow with a low tracking to the south. Wichita looked at the satellite loop, visibly saw the low tracking farther NW, and immediately cancelled their warnings in SE KS. The models were wrong. The heavy snow was confined to central and western KS with rain in SW MO. It was an awful, awful bust. Link to comment Share on other sites More sharing options...
MUWX Posted December 6, 2018 Share Posted December 6, 2018 8 minutes ago, JoMo said: Maybe, storm won't be fully sampled until tomorrow and any big changes in modeling will probably happen at that point. I remember, many years ago, a snowstorm that was supposed to impact the Springfield CWA. They had warnings up, the models had been indicating heavy snow with a low tracking to the south. Wichita looked at the satellite loop, visibly saw the low tracking farther NW, and immediately cancelled their warnings in SE KS. The models were wrong. The heavy snow was confined to central and western KS with rain in SW MO. It was an awful, awful bust. Yeah, I'm holding out hope for the sampling shift. I can't imagine this board in a miss like that! Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 6, 2018 Share Posted December 6, 2018 GFS at 3.3 inches by 21z Sat in Tulsa. That's already 2 inches more than previous run. Link to comment Share on other sites More sharing options...
Weatherdemon Posted December 6, 2018 Share Posted December 6, 2018 Link to comment Share on other sites More sharing options...
WhiteoutWX Posted December 6, 2018 Share Posted December 6, 2018 4 minutes ago, Weatherdemon said: GFS at 3.3 inches by 21z Sat in Tulsa. That's already 2 inches more than previous run. GFS just playing catchup. Gets the overall look a little better this time but the QPF is too low on the backside of the low. 3 Link to comment Share on other sites More sharing options...
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