April 24-30th Severe Potential

[WhiteoutWX]

Severe weather forecasting is a whole different ballgame. Plenty of great synopticians and east coast snowstorm experts (even professional) are fairly clueless about the intricacies, just as the converse is also true. I'm not really sure what "Soggy Plains may inhibit potential" is supposed to mean, but if it relates to the rain we got last week, I can't imagine any scenario where that hurts us. In summary, I'd disregard.

 

00z GFS has somewhat caved to the eastern dryline placement. I think any hope for a true chaser-friendly outcome where mature storms are rolling across wheat fields in Harper Co. KS and Major Co. OK at 00z Wed is close to being out the window. The big question will be the magnitude of the I-35 threat, as things stand.

I know the Euro also has the dryline east but I can't think of a single case the past few years where the GFS wasn't too far east with dryline placement at this range. If anything you would expect the recent rainfall would exaggerate this error even further. 

 

It almost always seems that the forecast dryline position ends up backing west within ~72 hours.

[jojo762]

I couldn't careless about the chaser prospects for this really. Looks pretty awesome as of now. Also, I wouldn't focus on the little things like a small difference in STP or SCP from run to run, unless it becomes a trend. Whether the STP is 5, 6, or 7+, it is still a volatile environment capable of tornadoes-- some strong/violent.

 

The subtle hint of a VBV there is something to watch in the 700-500 mb layer.

 

That CAPE profile is just nasty though, would be even more impressive if there was a bigger surface wind response (i.e. more towards the SE, which may very well still be in the cards considering the GFS' problems with this type of thing).

I think most surface winds across OK and KS will be almost due southeast on tuesday.

 

Also, on the issue of the DL, I really would expect that given all the recent rainfall, along with a few other factors, that the dry-line will not mix east of I-35 anytime before 00Z.

[JoMo]

I know the Euro also has the dryline east but I can't think of a single case the past few years where the GFS wasn't too far east with dryline placement at this range. If anything you would expect the recent rainfall would exaggerate this error even further. 

 

It almost always seems that the forecast dryline position ends up backing west within ~72 hours.

 

Yeah, the last few systems have ended up being slower/farther west, the closer we got to the event.

[jojo762]

The UVV from the GFS the last few days has cracked me up. It is literally trying to resolve-- and doing a somewhat good job of-- individual supercell updrafts despite its resolution.

 

Also, the 00Z GFS brings the warm-front much further north by thursday evening than the last few runs did.

[andyhb]

I could careless about the chaser prospects for this really.

 

*couldn't care less

[ClicheVortex2014]

I could careless about the chaser prospects for this really. Looks pretty awesome as of now. Also, I wouldn't focus on the little things like a small difference in STP or SCP from run to run, unless it becomes a trend. Whether the STP is 5, 6, or 7+, it is still a volatile environment capable of tornadoes-- some strong/violent.

 

I think most surface winds across OK and KS will be almost due southeast on tuesday.

 

Also, on the issue of the DL, I really would expect that given all the recent rainfall, along with a few other factors, that the dry-line will not mix east of I-35 anytime before 00Z.

 

Completely agreed. I had special interest in it this time because of the 12z run. If this is like most other times I've seen, GFS is underestimating moisture and/or directional shear... NAM is gonna come in hot... then NAM and GFS will trend toward Euro but will be a bit more toward NAM than GFS. The tug-of-war match is fun to watch.

[nwburbschaser]

*couldn't care less

Thank you. 

[ClicheVortex2014]

*couldn't care less

 

Thank you. 

 

The real important issues of the day

[jojo762]

The real important issues of the day

I did in fact correct it. Pointless stuff really, but eh whatever. "Could careless" isn't the grammatically correct phrase, but is more or less the sarcastic phrase. 

 

Next Saturday could yield some potential, given the breadth of the progged warm sector on the 00z GFS as well as potency of the shortwave coming through, would need more low-level backing though since a lot of-- or most of-- the flow is meridional in the mid and upper levels as of now.

[Chinook]

00z GFS shows a 114kt jet max at 300mb advancing into OK from 00z Wednesday to 06z Wednesday. In general, winds increasing with height from 500mb to 300mb is something that seems to help storms become long-track classic supercells. (given appropriate CAPE and SRH)

[andyhb]

Latest Euro run is looking really occluded on Tuesday.

[chase_stormz]

Latest Euro run is looking really occluded on Tuesday.

What about timing as compared to 12z?

[thewxmann]

Latest Euro run is looking really occluded on Tuesday.

 

Yeah. 500mb definitely not a lock. Initial wave is just arriving onshore, which will affect how the second wave amplifies and ejects Tuesday.

[jojo762]

00Z Euro looks like it could create VBV problems

as well as almost entirely meridional flow. Bleh. Hopefully it's just a flukey run.

[1900hurricane]

The UVV from the GFS the last few days has cracked me up. It is literally trying to resolve-- and doing a somewhat good job of-- individual supercell updrafts despite its resolution.

Also, the 00Z GFS brings the warm-front much further north by thursday evening than the last few runs did.

Last week, the GFS was doing something similar by trying to resolve a localized spot of >12" of rain somewhere in central or southeast Texas, and honestly, it did a pretty good job considering it started doing it several days in advance. It'll be interesting to see if it has a similar level of success this go around.

[Stebo]

The 00z Euro is occluded but that doesn't nix the potential and it is miles better than what the 12z Euro showed. The dryline is much closer to I-35 this run comparatively and the wind fields are still very good with good clockwise shear. Still not as great as the GFS but no where near the hot mess the 12z was. That should raise flags though with respect to trusting the Euro, it has had 3 model runs now in a row with 3 different solution sets for Tuesday.

[Quincy]

The 120hr EPS shows considerable spread, but is held back somewhat with the surface low. The plots from WeatherBELL show ROUGHLY 1/3 of the surface lows at 00z WED in the TX PH/far W OK, 1/3 in E CO/W KS and only ~1/3 near the OP position in NE or N KS.

It's not time to get too worried, but there continue to be some mixed signals/red flags. Not a slam dunk outbreak, but definitely not a setup to call off because of nuisanced details this far out.

[capbreak]

From a chasing perspective, I would take Osage Cuestas/Flint Hills near I35 terrain and road network vs Red Hills any day of the week. Still feel like this is going to end up in the Red Hills, for some reason.

On a slight tangent, where do IEM meteograms get their "NWS" values from? ICT/DDC/OKC/etc. are still showing dewpoints several degrees lower than what the GFS is forecasting, even though the SPC and individual AFDs from those areas don't seem as bearish as the "NWS" plots:

http://i.imgur.com/IXPGU2G.png

[ClicheVortex2014]

OUN

 

BY WEDNESDAY
NIGHT, SOUTHERLY WINDS WILL BRING BACK NORTH SIGNIFICANT MOISTURE
AND THE REMNANTS OF A WEAK FRONT MAY BE IN THE VICINITY OF THE RED
RIVER. MODELS INDICATE A SURFACE LOW SOMEWHERE IN THE TEXAS
PANHANDLE WHICH COULD PROVIDE A TRIPLE POINT THURSDAY IN OKLAHOMA.
THIS DAY MAY HAVE SIMILAR POTENTIAL FOR SEVERE WEATHER AS TUESDAY.
THE BOUNDARY MAY LINGER INTO FRIDAY AS WELL WITH ASSOCIATED
CHANCES FOR RAIN AND THUNDER.

 

[ClicheVortex2014]

TWC

 

https://weather.com/storms/tornado/news/severe-weather-forecast-outbreak-tornadoes-april-24-30-2016

 

Tuesday

• More widespread severe t-storms in parts of the central and southern Plains.
• Overall outbreak potential: Moderate to high
• Threats: Tornadoes (possibly strong/long-track), large hail, damaging winds

Wednesday

• Severe t-storms could again be rather numerous from the mid-Mississippi Valley to the southern Plains
• Overall outbreak potential: Moderate
• Threats: Tornadoes, large hail, damaging winds

Late next week

• Once again, more widespread severe t-storms are possible in the central and southern Plains, possibly extending east into parts of the Mississippi Valley.
• Severe t-storms are possible each day in these areas Thursday into next weekend (Apr. 30 - May 1).
• Overall outbreak potential: Too soon to tell, but could be at least moderate on one or more days.

[FHSC Sam]

 

TWC

 

https://weather.com/storms/tornado/news/severe-weather-forecast-outbreak-tornadoes-april-24-30-2016

 

Tuesday

• More widespread severe t-storms in parts of the central and southern Plains.
• Overall outbreak potential: Moderate to high
• Threats: Tornadoes (possibly strong/long-track), large hail, damaging winds

Wednesday

• Severe t-storms could again be rather numerous from the mid-Mississippi Valley to the southern Plains
• Overall outbreak potential: Moderate
• Threats: Tornadoes, large hail, damaging winds

Late next week

• Once again, more widespread severe t-storms are possible in the central and southern Plains, possibly extending east into parts of the Mississippi Valley.
• Severe t-storms are possible each day in these areas Thursday into next weekend (Apr. 30 - May 1).
• Overall outbreak potential: Too soon to tell, but could be at least moderate on one or more days.

 

It's impressive to me that they're bring up the possibility of strong tornadoes this soon. Yes, there is an appreciable risk, but it seems slightly presumptuous to bring that up when we're still six days out. Just shows the potential this system has, regardless of the current model trend. 

[JasonOH]

Not to go on a rant, but it is too far out to talk about strong tornadoes. Currently the models show the possibility, BUT the wave hasn't even been sampled yet. It could come in much weaker than modeled because of this. This sampling from sounding sites in CA is why the models typically shift about 60-72 hours from an event. If it is sampled to be weaker, the violent tornado risk can go away. I think it is just a grab for publicity and web traffic by TWC and many other outlets. While the outbreak wording isn't unwarranted, saying strong tornadoes is going too far at this point. None of the mesoscale models are currently in range, so many features are still in the dark, so I feel that it is unwise to be spreading the strong/long track tornado verbiage. I'm not saying that there is no chance of this happening, I'm just saying that at this point, it is not a good idea to make the strong tornadoes claim. When the TV/Social Media meteorologists overhype and it doesn't verify, the public looses confidence in all meteorologists, including the NWS.

Edit: I would like to add that Quincy does a very good job with his Twitter of not hyping everything. His Twitter is a good example of passing information along without hyping.

[FHSC Sam]

Not to go on a rant, but it is too far out to talk about strong tornadoes.  Currently the models show the possibility, BUT the wave hasn't even been sampled yet.  It could come in much weaker than modeled because of this.  This sampling from sounding sites in CA is why the models typically shift about 60-72 hours from an event.  If it is sampled to be weaker, the violent tornado risk can go away.  I think it is just a grab for publicity and web traffic by TWC and many other outlets.  While the outbreak wording isn't unwarranted, saying strong tornadoes is going too far at this point.  None of the mesoscale models are currently in range, so many features are still in the dark, so I feel that it is unwise to be spreading the strong/long track tornado verbiage. I'm not saying that there is no chance of this happening, I'm just saying that at this point, it is not a good idea to make the strong tornadoes claim.  When the TV/Social Media meteorologists overhype and it doesn't verify, the public looses confidence in all meteorologists, including the NWS.

I concur, although minus the strong tornado mention, this system is nothing to overlook.

[JasonOH]

I concur, although minus the strong tornado mention, this system is nothing to overlook.

Exactly.  The hype is already blowing through the roof and it is still day 6. 

 

I would like to add that due to how moist the soil is, I don't think the dryline will mix as far east as the GFS has it.  The GFS also tends to model drylines too far east so that factors into my thinking too.  I think the dews will definitely verify at least in the upper 60's due to moisture trajectories almost right out of the Gulf (and before that the Carribean).  This Sunday trough will help draw the moisture north, getting the moisture in place by Monday.  Even if the moisture return is slower, there is still extra time with this setup for the moisture to advect northward. 

[FHSC Sam]

Exactly.  The hype is already blowing through the roof and it is still day 6. 

 

I would like to add that due to how moist the soil is, I don't think the dryline will mix as far east as the GFS has it.  The GFS also tends to model drylines too far east so that factors into my thinking too.  I think the dews will definitely verify at least in the upper 60's due to moisture trajectories almost right out of the Gulf (and before that the Carribean).  This Sunday trough will help draw the moisture north, getting the moisture in place by Monday.  Even if the moisture return is slower, there is still extra time with this setup for the moisture to advect northward. 

Agreed. and it'll be interesting to see what the NAM brings into the picture. And honestly, this far North, in E Central KS, things have had some time to dry out a bit, so that might just depend on how this trough Sunday plays out. And while i'm on that topic, in my opinion, Sunday actually looks pretty volatile, but Tuesday and the rest of the week has stolen most of the attention from it. 

[OUGrad05]

Exactly.  The hype is already blowing through the roof and it is still day 6. 

 

I would like to add that due to how moist the soil is, I don't think the dryline will mix as far east as the GFS has it.  The GFS also tends to model drylines too far east so that factors into my thinking too.  I think the dews will definitely verify at least in the upper 60's due to moisture trajectories almost right out of the Gulf (and before that the Carribean).  This Sunday trough will help draw the moisture north, getting the moisture in place by Monday.  Even if the moisture return is slower, there is still extra time with this setup for the moisture to advect northward. 

Big show appears to be day 5 and day 7 best I can tell at this point...Your point about mixing east is spot on IMO.  The GFS has typically had these too far east in recent years with saturated ground.  I question how far off it is though...I could see this backing to the west a pretty significant distance though, 75 miles maybe....unfort that puts OKC still under the gun.  Additionally the system will be supportive of discrete supercells well after dark if things hold as depicted.  

It'll be Sunday morning before we can start really nailing this down.  At that point the sampling will be in and we'll have a great idea of what the system will look like.  I'm excited for some possible chase days next week but trying not to get hopes too high, especially if it winds up where it's currently depicted.  OKC and TUL would both be under the gun....

[OUGrad05]

Agreed. and it'll be interesting to see what the NAM brings into the picture. And honestly, this far North, in E Central KS, things have had some time to dry out a bit, so that might just depend on how this trough Sunday plays out. And while i'm on that topic, in my opinion, Sunday actually looks pretty volatile, but Tuesday and the rest of the week has stolen most of the attention from it. 

Agreed, seems Sunday will have some tors in far northern OK to central and eastern KS and western MO.  

[Stebo]

12z GFS upped the instability some and moved the dryline back further west. Positive gains this run, putting C OK directly in the cross hairs.

[chase_stormz]

12z GFS upped the instability some and moved the dryline back further west. Positive gains this run, putting C OK directly in the cross hairs.

 

The instability values popping up on the conservative GFS are downright scary. 

[WhiteoutWX]

12z GFS upped the instability some and moved the dryline back further west. Positive gains this run, putting C OK directly in the cross hairs.

I think it still has a lot more room to back west. The NAM has the dryline on Monday in a much more believable position, in far western Oklahoma, while the GFS has it east of 35. You'd think if the GFS wasn't already so far east with its initial positioning Monday that Tuesday's position would end up much further west as well.