thewxmann Posted April 24, 2014 Share Posted April 24, 2014 Actually I'd argue the moisture quality in both the Rozel and Arnett cases were much better. We had quality dewpoints in the upper 60's/lower 70's not too far away. 65F might be a good threshold to watch Saturday. I'll be out there chasing for the first time on Saturday -- I'll be happy just with storm structure. Link to comment Share on other sites More sharing options...
CUmet Posted April 24, 2014 Share Posted April 24, 2014 Wow. That moisture is really going to mix out like a rock if the insolation is strong enough to heat the boundary layer to the 90s. Actually a big clue I noticed tonight: note the anticyclonic flow in the eastern GOM (again) prior and during the ejection of the trough. Moisture quality is going to be much better than it is tonight, but still not ideal because of this. The richer moisture is still confined to the Gulf Coast just 24h before the event. <65F and 90F -- a 25F T/Td spread -- is marginal to say the least for any tornado, much less a significant tornado. Something to watch. The EML really cranks up after dark as well as the LLJ veers and advects hotter 850mb air over the warm sector. You can clearly see the first trough and associated front really suppress the moisture all the way to the Gulf Coast in this GFS dprog/dt loop valid for 00z Saturday. The trends are clearly pointing to late moisture return for Saturday's event. Link to comment Share on other sites More sharing options...
Chicago Storm Posted April 24, 2014 Share Posted April 24, 2014 I'm getting onboard with your pessimism for Saturday regardless of initiation, especially after witnessing moisture today ahead of the dryline. The drought is absolutely killing us, and as usual, dew points will likely verify even lower than any of the current progs on Saturday afternoon. Weird things happen though. Arnett (5/4/07) and Rozel (5/18/13) are good examples where "skinny" but intense tornadoes have occurred in this part of the High Plains with large T-Td spreads but an otherwise favorable setup. As far as a widespread tornado event with multiple cyclic storms, I'd be pretty surprised. Reminds me a bit of the HIGH risk bust on 6/5/08. It's weird to think about LCL issues with theta-e and CAPE are through the roof, and dew points are well above 60 F, but temperatures of 90 F will do that to you. And you can and me onboard with that as well. Another terrible performance overall by guidance today regarding moisture. Funny you mention 5/18/13...I was just looking into that a little while ago. Link to comment Share on other sites More sharing options...
thewxmann Posted April 24, 2014 Share Posted April 24, 2014 You can clearly see the first trough and associated front really suppress the moisture all the way to the Gulf Coast in this GFS dprog/dt loop valid for 00z Saturday. The trends are clearly pointing to late moisture return for Saturday's event. Eye-opening, thanks for the link. Link to comment Share on other sites More sharing options...
thewxmann Posted April 24, 2014 Share Posted April 24, 2014 And you can and me onboard with that as well. Another terrible performance overall by guidance today regarding moisture. Funny you mention 5/18/13...I was just looking into that a little while ago. Didn't even follow today's events, but just tried to see what ended up verifying. The 0Z GFS last night forecasted 60F dewpoints to reach the OK/KS border. The actual 0Z dewpoint at Ponca City was 46F. Link to comment Share on other sites More sharing options...
andyhb Posted April 24, 2014 Author Share Posted April 24, 2014 Alright, as well roll out the coffins with the proverbial nails for the chasers on Saturday, it seems prudent to mention the moisture surge that both the Euro and GFS runs recently have been showing on Monday, that is one of the more classic indicators of something bad happening in Dixie Alley. Link to comment Share on other sites More sharing options...
Chicago Storm Posted April 24, 2014 Share Posted April 24, 2014 Didn't even follow today's events, but just tried to see what ended up verifying. The 0Z GFS last night forecasted 60F dewpoints to reach the OK/KS border. The actual 0Z dewpoint at Ponca City was 46F. Yea, it wasn't even close today. Outside of a few brief pockets of precip/convection induced 60F DP's, the main area stayed in SE. TX... A far cry from the stream of 60F+ DP's into KS by 0z shown about a day ago. Link to comment Share on other sites More sharing options...
Thunder Road Posted April 24, 2014 Share Posted April 24, 2014 I'm kinda novice to severe weather forecasting but, is anyone else worried about the cap building into southern-central Kansas after 00Z on Sunday on the 00Z GFS? yeah CIN increases rapidly. You're looking at 06z. In most cases, once you lose daytime heating, your boundary layer starts to decouple and you cool at the surface. There's nothing remarkable about seeing CIN increase after sunset; it's just a product of day turning into night. Link to comment Share on other sites More sharing options...
SouthernWx2 Posted April 24, 2014 Share Posted April 24, 2014 And James Spann is reporting that Birmingham NWS radio is down for most of the upcoming week. Not good for Dixie in the Monday period after this system progresses eastward from the plains Reportedly late this evening, the NWS office says repairs will be expedited and the transmitter back online before Monday morning. Link to comment Share on other sites More sharing options...
CUmet Posted April 24, 2014 Share Posted April 24, 2014 The 00z Euro verbatim once again depicts what would likely be a major tornado outbreak across the South on Monday. The past few runs of the GFS have trended towards a more broad-based trough akin to what the Euro has been showing, but isn't quite there yet in terms of the low-level jet response. There's a lot of uncertainty that remains, especially given that a lot is going to depend on vorticity maxima embedded within the larger scale trough, but I will say that the potential ceiling for Monday's event is very high. Link to comment Share on other sites More sharing options...
thewxmann Posted April 24, 2014 Share Posted April 24, 2014 How things have changed from 24h ago. The 0Z Euro is quite a positive change from 0Z GFS for chasers. The slower timing of the trof in the Euro gives hope for Sunday in decent chase territory, with better moisture too. CAPEs are also up for Sunday. The slowdown has turned from a negative into a positive. Link to comment Share on other sites More sharing options...
Misstertwister Posted April 24, 2014 Share Posted April 24, 2014 Guys, no weather guy here although I have learned quite a bit by following you alls posts and reading. What's y'all's thoughts on the potential placement for storms Saturday and Sunday especially with OKC marathon. Link to comment Share on other sites More sharing options...
MCS_hunter Posted April 24, 2014 Share Posted April 24, 2014 I'm still holding on to my glimmer of hope for Saturday. Link to comment Share on other sites More sharing options...
WxBlue Posted April 24, 2014 Share Posted April 24, 2014 Thought I would throw this in. CIPS data show that 7 pm CDT May 3, 1999 is the top analog from 00z GFS run. Of course this list will keep changing, but it's still unnerving to see that date on the very top of the list. Keep up with the great discussion for rest of us lurkers! Link to comment Share on other sites More sharing options...
soonertrey Posted April 24, 2014 Share Posted April 24, 2014 Things have gotten kind of quiet around here. What is the latest Euro run showing for Sat-Mon? I'm still unimpressed with Sat and Sun with the NAM and GFS latest runs. Link to comment Share on other sites More sharing options...
lowleveljet Posted April 24, 2014 Share Posted April 24, 2014 Things have gotten kind of quiet around here. What is the latest Euro run showing for Sat-Mon? I'm still unimpressed with Sat and Sun with the NAM and GFS latest runs. 12z Euro is just now coming in.... Link to comment Share on other sites More sharing options...
OUGrad05 Posted April 24, 2014 Share Posted April 24, 2014 I've been largely absent from making posts of real value in this thread, I apologize. I have been traveling for work this week and my conference/meeting schedule is packed beginning early morning till fairly late in the evening. So in looking at the NAM and GFS on twister data on break, I still have some concerns regarding the coverage and potential strength of severe storms this weekend. While parameters do look pretty good overall, CAPE values of below 2,000 isn't particularly impressive and hodographs aren't bad but not particularly good either just to the east of I35 on Sunday afternoon. Surface dewpoints of upper 60's to low 70s out ahead of the dryline is more adequate but not great, should things tend to the upper 60s instead of low 70s that could pose further limitations to the severe threat. A couple degrees either way in dewpoint will make a big difference. Just seems the lateset GFS and NAM are not particularly great even on some of the more basic parameters like DP. Link to comment Share on other sites More sharing options...
nwburbschaser Posted April 24, 2014 Share Posted April 24, 2014 Things have gotten kind of quiet around here. What is the latest Euro run showing for Sat-Mon? I'm still unimpressed with Sat and Sun with the NAM and GFS latest runs. This is turning into a pretty big letdown. Saturday is just about cooked, Sunday looks to be an early, messy show, and then Monday is just bad news all around so I'm not surprised that it got really quiet around here. Unless the Euro really comes in strong for Sunday then I think the chase prospects will be minimal. Link to comment Share on other sites More sharing options...
andyhb Posted April 24, 2014 Author Share Posted April 24, 2014 I've been largely absent from making posts of real value in this thread, I apologize. I have been traveling for work this week and my conference/meeting schedule is packed beginning early morning till fairly late in the evening. So in looking at the NAM and GFS on twister data on break, I still have some concerns regarding the coverage and potential strength of severe storms this weekend. While parameters do look pretty good overall, CAPE values of below 2,000 isn't particularly impressive and hodographs aren't bad but not particularly good either just to the east of I35 on Sunday afternoon. Surface dewpoints of upper 60's to low 70s out ahead of the dryline is more adequate but not great, should things tend to the upper 60s instead of low 70s that could pose further limitations to the severe threat. A couple degrees either way in dewpoint will make a big difference. Just seems the lateset GFS and NAM are not particularly great even on some of the more basic parameters like DP. What? Upper 60s/low 70s dews out ahead of a dryline is high octane. Pretty sure many chasers would hack limbs off for that to be the case on Saturday. Link to comment Share on other sites More sharing options...
OUGrad05 Posted April 24, 2014 Share Posted April 24, 2014 If daytime temps are low 90s? high base supercells, sure, great tornado chase day? Maybe not Link to comment Share on other sites More sharing options...
Chicago Storm Posted April 24, 2014 Share Posted April 24, 2014 What? Upper 60s/low 70s dews out ahead of a dryline is high octane. Pretty sure many chasers would hack limbs off for that to be the case on Saturday. No doubt. Link to comment Share on other sites More sharing options...
thewxmann Posted April 24, 2014 Share Posted April 24, 2014 Things have gotten kind of quiet around here. What is the latest Euro run showing for Sat-Mon? I'm still unimpressed with Sat and Sun with the NAM and GFS latest runs. This event is toast... the crickets tend to come out in these threads when it's evident that that is happening. Link to comment Share on other sites More sharing options...
OUGrad05 Posted April 24, 2014 Share Posted April 24, 2014 No doubt. Pretty significant difference between a 67* and 72 or 73* DP. Models don't look particularly impressive right now. Link to comment Share on other sites More sharing options...
ZackH Posted April 24, 2014 Share Posted April 24, 2014 When storms initiate Saturday you're not looking at 90 degree temps though... you're looking at a cooling boundary layer... Saturday definitely won't be an outbreak but it still has plenty of good chase potential. Sent from my LG-LS980 using Tapatalk Link to comment Share on other sites More sharing options...
brettjrob Posted April 24, 2014 Share Posted April 24, 2014 This is turning into a pretty big letdown. Saturday is just about cooked, Sunday looks to be an early, messy show, and then Monday is just bad news all around so I'm not surprised that it got really quiet around here. Unless the Euro really comes in strong for Sunday then I think the chase prospects will be minimal. Pretty good summary. I'm an eternal pessimist and even I wouldn't go quite that far in condemning the Saturday-Sunday period, but those two days as a whole look like a disappointment compared to earlier this week. More than likely, it will take luck to find the needle-in-the-haystack both days (assuming there are sustained supercells Saturday at all). And really, if you consider the year-to-date and the pattern that will dominate for at least 7-10 days after this, that's not what most of us were looking for. As for Monday, it's technically (mainly) out of this subforum, it's over unchaseable terrain with poor visibility and a tendency for grungy storms and haze, and it's over a more populated region. Bad news indeed, from just about every angle. I'd rather the system just fill and shear out after Sunday, but that's a far cry from what will happen. Link to comment Share on other sites More sharing options...
OUGrad05 Posted April 24, 2014 Share Posted April 24, 2014 When storms initiate Saturday you're not looking at 90 degree temps though... you're looking at a cooling boundary layer... Saturday definitely won't be an outbreak but it still has plenty of good chase potential. Sent from my LG-LS980 Hmm interesting point, I hadn't really thought about. Link to comment Share on other sites More sharing options...
thewxmann Posted April 24, 2014 Share Posted April 24, 2014 I've been largely absent from making posts of real value in this thread, I apologize. I have been traveling for work this week and my conference/meeting schedule is packed beginning early morning till fairly late in the evening. So in looking at the NAM and GFS on twister data on break, I still have some concerns regarding the coverage and potential strength of severe storms this weekend. While parameters do look pretty good overall, CAPE values of below 2,000 isn't particularly impressive and hodographs aren't bad but not particularly good either just to the east of I35 on Sunday afternoon. Surface dewpoints of upper 60's to low 70s out ahead of the dryline is more adequate but not great, should things tend to the upper 60s instead of low 70s that could pose further limitations to the severe threat. A couple degrees either way in dewpoint will make a big difference. Just seems the lateset GFS and NAM are not particularly great even on some of the more basic parameters like DP. I'd pay good money for upper 60's DP's on Saturday. Looking more like dewpoints are going to be in the lower 60's on Saturday (maybe even lower). Maybe Sunday we can have upper 60's DP's but the slopfest will negate that advantage. Link to comment Share on other sites More sharing options...
ZackH Posted April 24, 2014 Share Posted April 24, 2014 Keep in mind all models are also breaking out dryline convection in between 00z-03z still also. I still like Saturday's potential from a chasing perspective. Rozel wasn't much different. Dews were higher but so were temps. If the GFS is right there will also be more upper level support. Sent from my LG-LS980 using Tapatalk Link to comment Share on other sites More sharing options...
OUGrad05 Posted April 24, 2014 Share Posted April 24, 2014 I'd pay good money for upper 60's DP's on Saturday. Looking more like dewpoints are going to be in the lower 60's on Saturday (maybe even lower). Maybe Sunday we can have upper 60's DP's but the slopfest will negate that advantage. I agree upper 60s seems unlikely Saturday. Possible Sunday though. Link to comment Share on other sites More sharing options...
ZackH Posted April 24, 2014 Share Posted April 24, 2014 Think I'm playing the cold core target Sunday. Sent from my LG-LS980 using Tapatalk Link to comment Share on other sites More sharing options...
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