Quincy Posted June 9, 2017 Share Posted June 9, 2017 2 hours ago, jojo762 said: After this period remains a bit uncertain ATTM... But currently leaning toward the inevitable, and dreaded, death ridge developing by ~June 20, likely ending any legit severe/tornado prospects for the central/southern plains for quite some time. Aside from some pronounced western CONUS ridging in the June 16-21 window, today's new Euro weeklies suggest that the late June to early July period stays relatively active in the north-central states. Yes, the severe season south of I-80 should largely be done after next week, but that's climo for you. After mid-June it's pretty tough to get anything significant in Kansas and points south, barring some anomalous trough or unusual mesoscale accident. As for ridging, the weeklies keep that across the southern tier with generally AOB average 500mb heights across Montana/Dakotas into at least the first third of July. 2 Link to comment Share on other sites More sharing options...
andyhb Posted September 16, 2017 Author Share Posted September 16, 2017 Pending enough moisture return, Tuesday (9/19) could offer a fairly substantial severe risk across the Dakotas mainly. Consensus for a strong, negatively tilted shortwave pivoting east/northeast out of that large trough in the northwest with a broad, 40-50 kt southerly/south-southeasterly LLJ axis becoming established by 21z Tuesday. Don't see many problems with forcing for ascent (so much so that fairly quick linear transition is more of a concern than a cap bust), and if enough southwesterly 500 mb flow can overlap the LLJ axis, deep layer shear shouldn't be an issue either. Seems to me like it could be the first healthy risk of the "second season". Also, the primary trough/ULL remains in the west in behind, which could lead to further potential later in the week, although that's still TBD. Link to comment Share on other sites More sharing options...
andyhb Posted February 2, 2018 Author Share Posted February 2, 2018 12z Euro was showing a fairly significant severe weather setup (first of the year if it comes into fruition) over the Red River Valley eastward into the Arklatex on Tuesday. Link to comment Share on other sites More sharing options...
rolltide_130 Posted February 15, 2018 Share Posted February 15, 2018 Euro holding on to what may be a potentially substantial threat on Monday across areas E of I-35 and into AR/MO. Almost looks like more of an April/May setup with how much that SE ridge is pumping itself up, and this will be coupled with a strong LLJ response. This could be the first significant severe threat of the year.. Link to comment Share on other sites More sharing options...
monsoonman1 Posted February 15, 2018 Share Posted February 15, 2018 12z GFS also starting to look better. Guessing some folks will get their first chase on Monday.Sent from my SM-G920V using Tapatalk Link to comment Share on other sites More sharing options...
monsoonman1 Posted February 19, 2018 Share Posted February 19, 2018 SPC has outlined Day 6 from east TX into AR and MS/AL. Only thing holding the setup back right now is lack of instability, but that could easily change so better keep an eye on this. Link to comment Share on other sites More sharing options...
andyhb Posted February 19, 2018 Author Share Posted February 19, 2018 For now all I will say on that is a warm sector as extensive (with quality BL moisture) as is being progged by the GFS and Euro for Saturday generally yields problems in the cold season. A lot of details to be sorted out surrounding the influence of the strong SE ridge and the trough's ejection though. 1 Link to comment Share on other sites More sharing options...
bjc3395 Posted February 27, 2018 Share Posted February 27, 2018 Sunday could be an interesting day in the plains. Not sure the moisture will make it but.. We will see. The shear will be there, I'm just not entirely sure with that lead system that we will have much moisture to work with. Probably worth watching. Link to comment Share on other sites More sharing options...
Quincy Posted February 28, 2018 Share Posted February 28, 2018 11 hours ago, bjc3395 said: Sunday could be an interesting day in the plains. Not sure the moisture will make it but.. We will see. The shear will be there, I'm just not entirely sure with that lead system that we will have much moisture to work with. Probably worth watching. A 995mb low in western Kansas would be much more interesting even just a month from now. Still, cold air aloft is promoting some fairly steep lapse rates in the model progs, along with modest instability. Low level moisture looks better across the southern High Plains, but forcing will be weaker there, along with less steep mid-level lapse rates. Moisture looks awfully marginal (low to perhaps mid-50s) in western/central Kansas, but lapse rates become quite steep (8-9C/km) closer to the surface low, where forcing will be maximized. We are getting into March, so it wouldn't be completely uncharted territory for some severe hail in the area. Anything beyond that seems too early to speculate at this point. Link to comment Share on other sites More sharing options...
bjc3395 Posted February 28, 2018 Share Posted February 28, 2018 17 hours ago, Quincy said: A 995mb low in western Kansas would be much more interesting even just a month from now. Still, cold air aloft is promoting some fairly steep lapse rates in the model progs, along with modest instability. Low level moisture looks better across the southern High Plains, but forcing will be weaker there, along with less steep mid-level lapse rates. Moisture looks awfully marginal (low to perhaps mid-50s) in western/central Kansas, but lapse rates become quite steep (8-9C/km) closer to the surface low, where forcing will be maximized. We are getting into March, so it wouldn't be completely uncharted territory for some severe hail in the area. Anything beyond that seems too early to speculate at this point. Definitely worth watching, the wind profiles over the warm sector and along the dry line are extremely impressive (at least on the GFS, haven't checked the ECMWF). Latest GFS even cracks 60 F Td into SW OK, with pretty solid early March lapse rates to boot. The problem isn't really the moisture as much as it seems to be the heating. Widespread cloud cover, I'm guessing, would be likely on the heels of that strong frontal push into the GoM. Neat as always to get a system like this early in the season, but as is typical, it comes on the heels of a strong cyclone and anticyclone pairing to the east, driving moisture out into the GoM just before.. Hard to see much to chase on Sunday. Going to follow, but plenty will need to be overcome for this to be anything noteworthy. Link to comment Share on other sites More sharing options...
jojo762 Posted March 1, 2018 Share Posted March 1, 2018 7 hours ago, bjc3395 said: Definitely worth watching, the wind profiles over the warm sector and along the dry line are extremely impressive (at least on the GFS, haven't checked the ECMWF). Latest GFS even cracks 60 F Td into SW OK, with pretty solid early March lapse rates to boot. The problem isn't really the moisture as much as it seems to be the heating. Widespread cloud cover, I'm guessing, would be likely on the heels of that strong frontal push into the GoM. Neat as always to get a system like this early in the season, but as is typical, it comes on the heels of a strong cyclone and anticyclone pairing to the east, driving moisture out into the GoM just before.. Hard to see much to chase on Sunday. Going to follow, but plenty will need to be overcome for this to be anything noteworthy. Perhaps I am over-emphasizing this in my head with the very strong mid/upr trough overhead providing impressive forcing for ascent, but the 100-120+J/KG of CIN in the GFS soundings at 00z Monday (6pm Sunday) sticks out like a sore thumb to me. If we were to just get a relatively minor 3 to 5-degree improvement in DPs from what the 18z GFS run already progs in addition to less downstream convective overturning from crapvection earlier in the day, we would have an entirely different conversation on our hands, that is if you take the extremely impressive kinematics verbatim. Wind fields will probably be there as both the GFS and EURO show relatively similar setups attm imo. The current extreme D3 drought over the area where the dryline is currently progged to be lends to some additional concern over moisture quality as well. Link to comment Share on other sites More sharing options...
bjc0303 Posted March 1, 2018 Share Posted March 1, 2018 9 minutes ago, jojo762 said: Perhaps I am over-emphasizing this in my head with the very strong mid/upr trough overhead providing impressive forcing for ascent, but the 100-120+J/KG of CIN in the GFS soundings at 00z Monday (6pm Sunday) sticks out like a sore thumb to me. If we were to just get a relatively minor 3 to 5-degree improvement in DPs from what the 18z GFS run already progs in addition to less downstream convective overturning from crapvection earlier in the day, we would have an entirely different conversation on our hands, that is if you take the extremely impressive kinematics verbatim. Wind fields will probably be there as both the GFS and EURO show relatively similar setups attm imo. The current extreme D3 drought over the area where the dryline is currently progged to be lends to some additional concern over moisture quality as well. I don't see the moisture being the problem as much as cloud cover inhibiting insolation (on the GFS at least). And this isn't overturning, either. With recent frontal intrusions comes airmass modification, and with isentropic upglide happening we can probably expect tons of cloud cover, at least early on. Guessing that's why the GFS isn't getting surface temps too high. ECMWF on the other hand puts out low 70s over a broader region. Find a sounding (on the GFS) with low 70s temperature and the inhibition is nearly gone even with upper 50s dewpoints. Not really time to get caught up in EML temperatures. The strength of the wave itself will provide some pretty impressive ascent. We'll see how much of that glances the southern portion of the dry line however. Link to comment Share on other sites More sharing options...
jojo762 Posted March 1, 2018 Share Posted March 1, 2018 11 minutes ago, bjc0303 said: I don't see the moisture being the problem as much as cloud cover inhibiting insolation (on the GFS at least). And this isn't overturning, either. With recent frontal intrusions comes airmass modification, and with isentropic upglide happening we can probably expect tons of cloud cover, at least early on. Guessing that's why the GFS isn't getting surface temps too high. ECMWF on the other hand puts out low 70s over a broader region. Find a sounding (on the GFS) with low 70s temperature and the inhibition is nearly gone even with upper 50s dewpoints. Not really time to get caught up in EML temperatures. The strength of the wave itself will provide some pretty impressive ascent. We'll see how much of that glances the southern portion of the dry line however. Not sure why I mentioned overturning, misplaced some of the precip and VV maps in my head apparently while doing calc. Will be interesting to watch this evolve tonight, tomorrow and into this weekend. Any meaningful uptick in instability and moisture dramatically improves this system's prospects from what I can tell. Link to comment Share on other sites More sharing options...
Quincy Posted March 1, 2018 Share Posted March 1, 2018 Regarding moisture... notice how the dryline surges east on the GFS, outrunning the greatest surface heating, leaving only a narrow sliver of favorable low-level temperatures and moisture. Even though progs are in the ballpark of 70/60 near the Red River, warming around 850mb results in a sizable capping inversion, especially south of the KS/OK border. For reference, readings are in Celsius on this map, where 20C = 68F. Link to comment Share on other sites More sharing options...
bjc0303 Posted March 1, 2018 Share Posted March 1, 2018 8 minutes ago, Quincy said: Regarding moisture... notice how the dryline surges east on the GFS, outrunning the greatest surface heating, leaving only a narrow sliver of favorable low-level temperatures and moisture. Even though progs are in the ballpark of 70/60 near the Red River, warming around 850mb results in a sizable capping inversion, especially south of the KS/OK border. For reference, readings are in Celsius on this map, where 20C = 68F. Warmest temps are always behind the dry line.. The thermal axis should lie along and behind the dry line during max heating. Link to comment Share on other sites More sharing options...
Quincy Posted March 1, 2018 Share Posted March 1, 2018 7 minutes ago, bjc0303 said: Warmest temps are always behind the dry line.. The thermal axis should lie along and behind the dry line during max heating. Where are you seeing lower 70s on the GFS with upper 50s dew-points and minimal capping? That was my main point. Link to comment Share on other sites More sharing options...
bjc3395 Posted March 1, 2018 Share Posted March 1, 2018 12 hours ago, Quincy said: Where are you seeing lower 70s on the GFS with upper 50s dew-points and minimal capping? That was my main point. Not many. I see some mid-upper 60s over upper 50s (even low-60s Td). That said, it has nothing to do with how far east the dry line surged. The thermal axis will always lie behind the dry line.. that's just how it works. What you're seeing is the effect of widespread cloud cover by the GFS. The GFS has the entire warm sector underneath 85+% cloud cover, restricting temperatures in the mid 60s. There definitely will be a portion farther south that gets completely capped by 850mb warming. However, I am pretty convinced there's going to be surface-based severe storms somewhere along the dry line in W OK. The only way this doesn't happen is if widespread cloud cover mutes the diurnal heating cycle, suppressing the dry line circulation.. I question the GFS cloud cover output in this regard, even though widespread cloud cover is a possibility. I would expect it Saturday and Saturday night more so than Sunday.. Link to comment Share on other sites More sharing options...
jojo762 Posted March 1, 2018 Share Posted March 1, 2018 GFS seems to be slowly trending toward a tad better moisture return... Likewise forecast soundings on the 18Z GFS are seasonably impressive along a narrow corridor in close proximity to the dryline on Sunday evening from SW OK into SC KS, featuring an ideal hodograph for low-level mesocyclones and modest instability, not the best moisture quality obviously but probably do-able with the low LCLs, something of note is fairly respectable low-level instability which plays a significant role in tornadogenesis. This will be a fairly impressive early season setup (low/mod CAPE/ high shear) if we can just get a little more breadth to the axis of greatest instability. Not looking like an overly significant event attm, but definitely an interesting day for the beginning of March in the plains. BTW. this sounding is from just west of Enid at 6pm Sunday. Link to comment Share on other sites More sharing options...
WhiteoutWX Posted March 2, 2018 Share Posted March 2, 2018 I’m just hoping to see a hodograph that looks like that in May when when know moisture/instability will be there. So many junky hodographs the past few years in the southern plains. i think my question is if we can get convection to fire on the dryline. The ejecting shortwave is rather robust but the cap is definitely there and will still be hard to overcome if we can’t get some amount of warming to the east of the dryline. Hints of extensive cloud cover and showers in the models don’t lend confidence to that happening IMO, but obviously that type of thing is hard to forecast. It only takes a small window for something to produce with that shear profile. 2 Link to comment Share on other sites More sharing options...
Quincy Posted March 2, 2018 Share Posted March 2, 2018 The main limiting factor appears to be the quality of the warm sector. As discussed above, only a narrow area around the southwestern Oklahoma vicinity is progged to have (somewhat) favorable low level moisture, along with at least a possibility of convective temperatures being approached. The issue is that even within NAM range (taken with a large grain of salt at 72hrs), only a very tiny area (1-3 counties) comes within a couple of degrees of convective temperatures. The 00z NAM also shows no convection along the dryline. In addition, the NAM, too, favors the idea of >75% cloud cover across areas east of the dryline in Oklahoma. Synoptically, Sunday resembles 2/28/12, however, the warm sector this weekend is significantly smaller and far less impressive. If we had a deeper trough, a la 2/23/07, better forcing and mid-level cooling would result in much greater certainty of convective initiation along the dryline. Even the evolution of the surface low is not entirely clear. The 12z ECMWF shows a 995mb low up near I-80 in central Nebraska at 00z Mon, while the operational NAM still shows a focused low over western Kansas at the same time. The 18z GFS was somewhere between, while the 21z SREF shows substantial variability, ranging from an OP NAM solution to a more elongated low over the mid-Missouri Valley/Siouxland. Once we get into higher resolution model range and the operational models have some time to converge on a solution, then confidence may increase. Right now, the severe threat appears fairly conditional and perhaps more than one would expect for such a scenario in early March. The ongoing drought and (expected) relatively meager warm sector don't help matters either. As stated in the previous reply, the forecast shear profile won't need much to take things off. The low level thermodynamics just need to be improved... Link to comment Share on other sites More sharing options...
Quincy Posted March 3, 2018 Share Posted March 3, 2018 The 00z 3km NAM wasn't impressive at all, showing substantial cloud-cover ahead of the dryline with surface temperatures 5-10F shy of convective temperatures, even in the vicinity of a dryline bulge in the eastern Texas panhandle. Reflectivity progs concur with no convection. Meanwhile, the GFS came in a bit warmer in the western Oklahoma to central Kansas region, although still not quite robust enough for convection. I was intrigued to see the RGEM spit out convection in far southwestern Oklahoma between 21z Sun and 00z Mon. It makes sense based on what appears to be surface temperatures heating into the mid-70s in the presence of upper 50s to near 60F dew-points. I am still inclined to lean toward a non-event with cloud-cover mitigating surface heating (poor sfc-850mb lapse rates), despite favorable wind fields and nice looking thermodynamic profiles above 800mb. A highly conditional threat could still produce if surface heating improves, so I'd hold with a MRGL risk outlook for tonight's day 2 update. Link to comment Share on other sites More sharing options...
bjc0303 Posted March 3, 2018 Share Posted March 3, 2018 Agreed. It's a shame this Atlantic system had to blast a cold front into the Gulf. The second that happened, this one was pretty much dead. Strong moisture return on the heels of a frontal intrusion will always throw us under thick cloud cover, and that concerned me from the start. Given I live in OK, this one is still probably worth watching, especially morning of.. But I wouldn't exactly say I'm holding my breath on it. Link to comment Share on other sites More sharing options...
Sydney Claridge Posted March 4, 2018 Share Posted March 4, 2018 While little to no severe weather is expected today, the GFS seems to be suggesting the potential for a severe thunderstorm event next Saturday (3/10) for the Red River area of north-central Texas and southern Oklahoma into East Texas. CFS gives a stronger storm system with less instability (and brings some instability into NE OK), and GDPS (Canadian) seems to be a non-event for the southern Plains. Euro has the strongest system, bringing a sub-1000mb MSLP low from the Panhandle into NE OK, and then to the lower Ohio River valley. SPC says that the predictability is too low, but this is still 7 days out. Link to comment Share on other sites More sharing options...
jojo762 Posted March 4, 2018 Share Posted March 4, 2018 1 hour ago, BrandonC_TX said: While little to no severe weather is expected today, the GFS seems to be suggesting the potential for a severe thunderstorm event next Saturday (3/10) for the Red River area of north-central Texas and southern Oklahoma into East Texas. CFS gives a stronger storm system with less instability (and brings some instability into NE OK), and GDPS (Canadian) seems to be a non-event for the southern Plains. Euro has the strongest system, bringing a sub-1000mb MSLP low from the Panhandle into NE OK, and then to the lower Ohio River valley. SPC says that the predictability is too low, but this is still 7 days out. Definitely looks interestingly at this point in time. SPC provides a good take: "It appears that one or two short wave perturbations on the leading edge of this regime may dig to the lee of the Rockies and contribute to significant surface cyclogenesis anywhere from the southern Plains into the lower Mississippi Valley, and across parts of the Southeast, next weekend. Guidance remains suggestive that this could be accompanied by a fairly rapid and substantive moisture return off the Gulf of Mexico, providing potential for destabilization supportive of an increasing severe weather risk. Due to the rather large spread among the model output concerning these developments (associated with low pattern predictability and the extended time frame), severe weather probabilities for next Saturday/Sunday currently remain generally low, but it is at least possible that this could change during the coming days." 1 Link to comment Share on other sites More sharing options...
CheeselandSkies Posted March 5, 2018 Share Posted March 5, 2018 Can we please bottle the 300-hour 12Z GFS surface and H5 solution and have it verify in May, preferably when I'm on vacation? Sent from my SM-G955U using Tapatalk Link to comment Share on other sites More sharing options...
bjc0303 Posted March 8, 2018 Share Posted March 8, 2018 Operational GFS and CFS ensemble appear to suggest a looming pattern change in the 7-14 day window coinciding with the latest ERTAF week 3 forecast of AA tornado activity. Could be plains first decent period. 1 Link to comment Share on other sites More sharing options...
monsoonman1 Posted March 8, 2018 Share Posted March 8, 2018 Wouldn't sleep on Saturday, still some questions but parameters seem to be there.Sent from my SM-G920V using Tapatalk Link to comment Share on other sites More sharing options...
rolltide_130 Posted March 9, 2018 Share Posted March 9, 2018 6 hours ago, monsoonman1 said: Wouldn't sleep on Saturday, still some questions but parameters seem to be there. Sent from my SM-G920V using Tapatalk NE Texas may be needing a close watch.. this is definitely one of the more bizzare systems in terms of model handling that I've seen. Link to comment Share on other sites More sharing options...
bjc0303 Posted March 9, 2018 Share Posted March 9, 2018 GFS continues to advertise big time pattern shift, with significant shortwave traversing plains in the 8-10 day range. This coincides with some teleconnection/GWO phase space forecasts. With several days of return flow (even though prior cold front pretty significant), we could see a bit of an active stretch coming up. 1 Link to comment Share on other sites More sharing options...
Sydney Claridge Posted March 11, 2018 Share Posted March 11, 2018 GFS is showing a storm forming somewhere in the central Plains for next weekend. There's some run-to-run disagreement on where the humid air in the warm sector sets up though, as can be expected this far out. Today's 6z GFS run forms a major storm (probably overblown with sub-980mb MSLP tracking from CO into NE) and would suggest some severe weather potential for eastern OK and north central TX for next Sunday (3/18), albeit with some capping issues. Waiting for the 12z GFS to reach this time period to see what it shows... Link to comment Share on other sites More sharing options...
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