2025-04-01 EVENT TX/OK/KS/NE/MO/IA

[gdlewen]

Looking ahead to Tuesday which looks very promising at this time. 3 Day Convective Outlook puts the target up north, but I am eyeing the dryline mostly because I prefer dryline storms. The SPC discussion specifically mentioned the cap being the major factor inhibiting convection south of Kansas, so obviously that could ruin my day.

[4PM CDT] Edited to reflect 1930Z Day 3 Forecast, which expanded SLGT risk to include OK/TX (from Marginal):

1300Z SPC 3 Day Convective Outlook​	1930Z SPC 3 Day Convective Outlook​

It seems to me that, a few days out, the NAM always presents sharp, clean drylines; however 3 days out it is hard to ignore results like these.

NAM Forecast Supercell Composite for 00Z Wednesday April 2, 2025​	NAM Forecast 3km-EHI for 00Z Wednesday April 2, 2025​

With the Slight Risk currently assigned to KS-NE-IA-MO mainly due to elevated convection ahead-of and along a warm front advancing across KS/MO, I'm interested in what folks have to say about their plans for that area. There is a significant cold air mass at the surface forcast over IA/MO. We'll see how that holds. (The code to calculate that cold air depth is still experimental, and really only used to make sure my LSI calculations handle elevated convection correctly, so apologies for the odd outlier. Work in Progress.)

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[William Monfredo]

Sure wish some of these setups would realize we're on daylight savings time now and it's ok to initiate before sunset.

Was just about to say, Tuesday's setup looks ideal for a Plains outbreak if only the moisture were about 6 hours faster.

...mentioned the cap being the major factor...

Wish I felt better about the convective inhibition in Oklahoma, otherwise I'd be right on the road this morning.

 

[gdlewen]

Wish I felt better about the convective inhibition in OK, otherwise I'd be on the road right this morning.

I get it--although some of the CAM output available to the public shows convection occurring along the dryline (HRW-FV3 comes to mind, showing convection as early as 21Z), the capping is on the order of 3-5C under the EML. The 6Z SPC discussion specifically mentions better chances for convection in the "more mixed air mass farther west." At the same time, capping looks more favorable closer to NE, unless you are like me and like the isolated dry-line storms:

Capping over MO/IA forecast to be negligible.​

I think things are just going to get better, but I do wish moisture return was better in west-central OK. This "just-in-time" stuff really makes it hard to plan. However, for those local it can be a there-and-back-again in one day trip, so it is much harder for anyone more than a day's drive away.

 

[Jeff House]

I share the more optimistic outlook for Tuesday. Moisture and even temps are a little JIT just-in-time but that's par for the course early April.

One improvement is the neutral heights during the day on Tuesday now is forecast slightly falling. More than enough wind shear is present, both speed and direction. LLJ responds to the next upper jet max.

Severe hazards may depend on how well temps and dews recover. Hail followed by wind looks likely. Tornadoes are quite possible. I don't get the drive-by negativity. Add some bearish reasoning, and then being pessimistic is perfectly acceptable.

That said I'm in the chaser optimist camp for Tuesday. I have no skin in the game - too early season to travel for me. If the JIT surface works out the dynamics Tuesday are better than those back on Saturday.

 

[gdlewen]

I share the more optimistic outlook for Tuesday. Moisture and even temps are a little JIT just-in-time but that's par for the course early April.

One improvement is the neutral heights during the day on Tuesday now is forecast slightly falling. More than enough wind shear is present, both speed and direction. LLJ responds to the next upper jet max.

I did see the height falls and they definitely were discouraging last night.

However, the 36 Hour (NAM 12Z Valid 00Z 4/2/2025) Moisture Convergence is much improved over preceding runs.

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LSI analysis for the event is improving. I know this is not what everyone is used to using but the reduced model output like Supercell Composite and EHI are available in lots of places and they look similar to the images in the opening post. (Except STP which is much improved in OK).

Base on an LSI≤2˚K, just east of the dryline and over IA/MO are the places where "if deep convection forms it is likely to be severe".

Lid Strength Analysis for 00Z 4/2/205​	Capping has weakened E of the dryline​

 

[Mike Smith]

I'm surprised there is so little interest in today (Tuesday). While a few models show initiation as early as 22Z, most have it 2-3 hours later. However, I think tornadogenesis will be relatively quick. Sunset at ICT is 7:52 and it is light until ~8:15, so there should be time to catch some action since there will be scattered supercells until they merge with the line during the night.

As to "where," you can pick about any location from the Red River to I-70. The HRRR has an incredibly intense (for April) low near the triple point just south of DDC at 02Z with pressures falling incredibly fast (late night tornadoes, anyone?).

I think Kansas is the surer thing today as I went back and looked at April 29, 2022, and all of the 3 primary CAMS drew huge rotation tracks south of I-40 which didn't materialize. The HRRR did the best that day.

I like Kansas along and south of U.S. 50 east to Highway 75.

Good luck.

 

[gdlewen]

I'm surprised there is so little interest in today (Tuesday). While a few models show initiation as early as 22Z, most have it 2-3 hours later. However, I think tornadogenesis will be relatively quick. Sunset at ICT is 7:52 and it is light until ~8:15, so there should be time to catch some action since there will be scattered supercells until they merge with the line during the night.

As to "where," you can pick about any location from the Red River to I-70. The HRRR has an incredibly intense (for April) low near the triple point just south of DDC at 02Z with pressures falling incredibly fast (late night tornadoes, anyone?).

I think Kansas is the surer thing today as I went back and looked at April 29, 2022, and all of the 3 primary CAMS drew huge rotation tracks south of I-40 which didn't materialize. The HRRR did the best that day.

I like Kansas along and south of U.S. 50 east to Highway 75.

Good luck.

I have to admit I was surprised as well that there was not more discussion. I was at first committed to the dryline but became less certain and looking more towards KS after the 00Z model runs so I appreciate your input!

 

[gdlewen]

[EDITED to replace 6Z with 13Z] SPC 13Z Outlook has upped the ante to ENH risk over north-central OK to south-central KS, but the discussion indicates the primary threat will be from 02Z-03Z and away from the dryline.

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[Sean Ramsey]

I'm definitely in on today. HRRR keeps coming up with one or two isolated but quick moving cells with two hours of my location and has even given the courtesy of daylight to actually see them. Most everything else looks to be well after dark and further north into Kansas so my bet is on the dryline between 22z and 0z along I-35 somewhere between Guthrie and Ponca City and roll northeastward from there.

 

[gdlewen]

LSI Analysis based on 12Z NAM runs suggests two foci for convection: E of the dryline and (more or less) along the warm front forecast to be straddling E-KS to NW AR, the latter LSI focus mostly mostly due to an axis of lower capping and better buoyancy. HRRR and NAM-3km both show cells forming in (or around) the LSI tongue W of OKC and much earlier, so that is my target.

LSI = LID + BUOYANCY in Carlson et.al. formalism so if you have two you get the third but it still helps to see all three.

Capping is stronger over my target, though, but the timing will be better if the models are right and I will have more favorable territory between me and the poor road network E/NE of Ponca City.

We'll see.

 

[Brian McKibben]

Checking the 700mb geopotential heights on the RAP (or any model). You can see the 300 dam go from NW OK to south of I-44. There is an almost microscale SW at 700. Or is this simply from mixing of the PBL.

Either way we should be able to erode the cap to get CI along the DL.

The TTU WRF has a very impressive DL bulge in western OK.

 

[Brian McKibben]

Heres what i was talking about with the 700mb chart. On the left is the HRRR @ 4pm. I highlighted the 300 dam line. Notice its position and its straight. Next is the HRRR @ 6pm. Now its arced and about 30 miles further southeast. The result @ 7pm is a storm along I44 OKC

 

[Jason N]

OK/KS area today: overall guidance is leaning towards some potential with a few small details that could kink some outcomes possibly. Few hours past 12Z with some recent data, and right now at least.... notwithstanding, eventual changes in the dynamics of the day, and the realities of EML/Moisture push north from TX as well as timing of mid-level trough, and dryline kick. but it seems like Stillwater, Perry to Tonkawa could be good staging areas today? for North/South/East shoots, depending on the potentially very crowded boom or bust scenario possibly setting up.

The HRRR/RAP/GFS convective solution shows CNTRL-ESTRN OK (OKC/TULSA) area while higher-Res RAP/HRRR place potential IVO El Reno to downtown (W , N or S of there) with a possible further north mass chaser convergence SE of Wichita. (Coffeeville?) HRRR has been consistent with POPS however, so it will be interesting to see it pan out.

FV3 showing a Red River shot and further east CI towards the AR border with more nocturnal convection popping with front/trough.

Both the ARW's appear convectively cool throughout OK, with consistent agreement closer to the SFC low KS/NE, so there is some disagreement on location timing and stability and convective outcomes across OK today. Could be some parameterization or Bias for keeping convection out of OK but I am unsure at this point.

Cloud canopy- noticed models keeping clouds SCT/BKN through 20Z across the CTRL OK area. (ConvT issue?) or will (SFC - Mid Level dynamics override it)

BL:
I think it's going to come down to an 18Z re-analysis of the situation prior to potential CI timing today to check METSAT & Meso-analysis with a final look at the HRRR/FV3 if you're a believer, or if it's signaling a bust, to make a run to the north, but be in more of a messy convective mode. and rapidly diminishing moisture, but high shear environment, further into KS.

 

[Jason N]

thanks to whomever moved my post lol.. I wasn't totally sure what room was the more appropriate one lol.

 

[Amelia Urquhart]

I put together a map of Canadian River crossings for my own chasing today since it's something I've been concerned about. Hopefully it ends up useful for y'all Canadian River and Red River Crossings – Google My Maps