March 15-16, 2023 | Severe Storms

[Iceresistance]

One during Spring Break? My Local TV Mets have mentioned it and there is some model backup to it.

 

SPC has this for now

Spoiler

Another western trough may amplify around Thursday/D8, but predictability for this is quite low.

 

[Hoosier]

One of my concerns would be quality of moisture return.  Gulf is pretty scoured prior to this.  Of course you don't need as long of a period of moisture return compared to areas in more northern latitudes.  To me it seems like a setup that may produce severe wx, at least in the southern Plains, but I'd question the overall magnitude and northern extent.  Plenty of time to watch though.

[ElectricStorm]

At the moment, I don't really see much happening with this, maybe a couple marginal risk days, but moisture really seems lacking for anything significant. Still a ways out so definitely time for it to change, but I'm not really expecting much for now. 

[Iceresistance]

From the SPC for 3.10.2023

 Although details remain uncertain, most guidance suggests that
   another large-scale upper trough should move eastward across the
   western/central CONUS during the middle to latter portion of next
   week. At this point, low-level moisture return ahead of this feature
   appears rather limited. While an isolated severe risk may ultimately
   evolve from Day 7/Thursday into Day 8/Friday across some part of the
   southern Plains into the lower MS Valley/Southeast, predictability
   remains far too low to include any 15% severe probabilities at this
   extended time frame.

 

[ElectricStorm]

If the recent GFS runs are correct, the next 2 cold fronts could make it pretty far into the gulf. If that happens, we probably won't see a widespread severe weather event for at least the next couple weeks or so. There will be some low end localized days, but probably nothing major. 

I think around or just after 3/20 or so we could start to see some bigger events but we'll see. 

Edited March 10, 2023 by ElectricStorm

[Iceresistance]

2 hours ago, ElectricStorm said:

If the recent GFS runs are correct, the next 2 cold fronts could make it pretty far into the gulf. If that happens, we probably won't see a widespread severe weather event for at least the next couple weeks or so. There will be some low end localized days, but probably nothing major. 

I think around or just after 3/20 or so we could start to see some bigger events but we'll see. 

If we have a slow March, could that be replaced with a nasty active April and/or May?

[ElectricStorm]

35 minutes ago, Iceresistance said:

If we have a slow March, could that be replaced with a nasty active April and/or May?

I don't really think March activity really has any correlation to April/May activity 

[Neoncyclone]

3 hours ago, ElectricStorm said:

I don't really think March activity really has any correlation to April/May activity 

Yeah, there's not much of a correlation there, we're still above-average for the season thus far but early season activity also doesn't really correlate to the rest of the season being above-average either.

[Grace]

If MJO gets to Phase 2 ya better watchout. 

[Neoncyclone]

7 hours ago, Grace said:

If MJO gets to Phase 2 ya better watchout. 

That's a great point, MJO phase is really the best we have for predicting patterns that then create severe weather, Can't predict specifics but helps hone in on the pattern. 

Edited March 12, 2023 by Neoncyclone

[ElectricStorm]

GFS has uptrended for moisture in TX for Thursday, could see some action there potentially. Need to watch capping though. 

[Iceresistance]

I knew it!

Spoiler

Guidance remains in good agreement that a southern-stream shortwave trough will eject over the southern Plains on Day 4/Thursday. At least upper 50s to perhaps mid 60s surface dewpoints should return northward ahead of this upper trough across parts of central/east TX/OK into the ArkLaTex vicinity. As mid-level temperatures cool and daytime heating occurs, weak to moderate instability is forecast to develop by Thursday afternoon along and ahead of a surface dryline.

Ascent attendant to the shortwave trough should encourage robust convective development along much of the length of the dryline late Thursday afternoon and evening. Strong deep-layer shear will easily support organized convection, including the potential for supercells with a large hail and damaging wind threat. Additional severe convection may develop Thursday night across portions of east TX into the ArkLaTex in a strengthening low-level warm advection regime. Even though low-level moisture should remain somewhat limited, enough low-level shear should be present to support some threat for a few tornadoes as well. Confidence in scattered severe convection occurring has increased enough to introduce a 15% severe area for Thursday.

 

Edited March 13, 2023 by Iceresistance

[Grace]

GOM certainly providing fuel if the right setup occurs 

 

[Iceresistance]

SREF STP already at 45% in Texas, the slight risk shifted south to include most of Texas, it's broad and an upgrade to "Enhanced" is likely.

[Iceresistance]

Which site does the CWASP model?

[ClicheVortex2014]

12 hours ago, Iceresistance said:

SREF STP already at 45% in Texas, the slight risk shifted south to include most of Texas, it's broad and an upgrade to "Enhanced" is likely.

That's significant tornado ingredient, not significant tornado parameter. Different things go into STI than STP, which is why STI is a percent probability and STP is more of a value

Edited March 15, 2023 by ClicheVortex2014

[Iceresistance]

2 minutes ago, ClicheVortex2014 said:

That's significant tornado ingredients, not significant tornado parameter. Different things go into STI than STP. Also, STP isn't a percent

Whoops. The STI is now at 75%, and the STP is at 4.

[snowlover2]

Enhanced area added on new da2 for wind/hail.

Quote

Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0100 AM CDT Wed Mar 15 2023

   Valid 161200Z - 171200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   NORTH-CENTRAL/NORTHEAST TEXAS...SOUTH-CENTRAL/SOUTHEAST
   OKLAHOMA...AND FAR SOUTHWEST ARKANSAS...

   ...SUMMARY...
   Scattered severe thunderstorms capable of producing large hail,
   damaging winds, and a few tornadoes appear likely Thursday into
   Thursday night across parts of the southern Plains, ArkLaTex, and
   lower Mississippi Valley. Some of the hail could be very large over
   south-central Oklahoma and north-central Texas.

   ...Southern Plains into the Lower Mississippi Valley...
   A southern-stream shortwave trough will eject eastward from northern
   Mexico and the Southwest across the southern Plains and lower MS
   Valley on Thursday. A lead low-amplitude shortwave trough is also
   forecast to advance quickly northeastward from the southern Plains
   to the MS Valley and Midwest through the day. A surface low
   initially centered over KS should develop northeastward towards the
   mid MS Valley by Thursday afternoon. A secondary surface low should
   form over western north TX and shift eastward along/near the Red
   River through Thursday evening. A cold front will sweep
   southeastward over much of the southern Plains into the lower MS
   Valley through the period. A dryline tied to the secondary surface
   low will mix eastward across central TX through late Thursday
   afternoon.

   Low-level moisture characterized by upper 50s to mid 60s surface
   dewpoints will continue to stream northward ahead of both the cold
   front and dryline. Some guidance suggests that convection may be
   ongoing at the start of the period Thursday morning across parts of
   TX/OK. This activity will be tied to strong lift/warm advection
   associated with a pronounced low-level jet. Even though they should
   have a tendency to remain elevated, some of these thunderstorms
   could pose an isolated threat for hail/wind through the early
   afternoon as the move quickly northeastward. Otherwise, daytime
   heating along/near the dryline, but west of any morning convection,
   should encourage the development of moderate instability across
   parts of north-central/northeast TX and far southern OK. With
   steepening lapse rates aloft also expected, MLCAPE of 1500-2500 J/kg
   seems probable by late Thursday afternoon across this region.

   Initial convective development near the triple point and southward
   along the dryline will likely be supercellular given 50+ kt of
   effective bulk shear forecast. These supercells will pose a threat
   for large hail, some of which could be 2+ inches in diameter.
   Somewhat weaker instability farther north in central/eastern OK and
   western AR should also support a large hail threat with any
   initially discrete development. Convection will grow upscale into an
   MCS along the front Thursday evening, with a greater threat for
   severe/damaging winds, especially across northeast TX/southeastern
   OK and vicinity. There are still some differences in guidance
   regarding the strength and placement of a south-southwesterly
   low-level jet Thursday evening across east TX into the ArkLaTex and
   lower MS Valley. Most guidance, with the 00Z NAM the notable
   exception, shows the low-level wind fields gradually
   weakening/veering with time along/ahead of the front. Regardless,
   ample low-level shear should be present from late Thursday afternoon
   through Thursday night to support a threat for a few tornadoes, both
   with supercells ahead of the front, and with circulations embedded
   within the line.

   Additional robust convection should develop across central/
   south-central and coastal southeast TX Thursday night into early
   Friday morning, with a continued threat for mainly damaging winds
   given the linear mode expected. The eastern portion of the MCS will
   eventually encounter less instability over the lower MS Valley late
   in the period, which should result in a gradually lessening damaging
   wind threat with eastern extent.

   ..Gleason.. 03/15/2023

 

[Iceresistance]

9z SREF has SCP parameters close to double digits in Texas.

 

Max STI has dropped to 60%, but it's much larger in the 60% range.

Edited March 15, 2023 by Iceresistance

[Iceresistance]

The HRRR is highlighting the possibility of the Triple Point Supercells in Oklahoma, this is something that can't be ignored if the storm system is slowing down (Trending west and/or north)

[Iceresistance]

Enhanced risk larger

[ClicheVortex2014]

Storm mode looks messy without particularly impressive shear or low-level instability. Not favorable for a bigger tornado event., but we'll see if a supercell can overachieve

[Chinook]

Maybe some supercells east of Dallas, near Dallas, or in southern Oklahoma

[Iceresistance]

It only got down to the upper 50s last night, DP is 55°F.

 

Severe Storms may initiate as early as 1 PM.

[Iceresistance]

Uh oh

Mesoscale Discussion 0290
   NWS Storm Prediction Center Norman OK
   1027 AM CDT Thu Mar 16 2023

   Areas affected...portions of southwest into central OK

   Concerning...Severe potential...Watch possible 

   Valid 161527Z - 161730Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Thunderstorm coverage is expected to increase from
   southwest into central OK over the next 1-2 hours. Hail will be the
   main hazard with initial thunderstorms into early afternoon. A watch
   may be needed in the next hour or so.

   DISCUSSION...Areas of deeper convective cells are developing within
   broader area of showers across western OK late this morning ahead of
   a fast, southeastward-advancing surface cold front. An elevated
   mixed-layer noted in 12z regional RAOBs may result in initial
   thunderstorm activity remaining elevated. Also, as the cold front
   quickly progresses southeast, initial storms late this morning into
   midday may quickly become undercut by the front. Forecast RAP/NAM
   soundings indicate some erosion of steeper midlevel lapse rates is
   occurring as early showers move across central OK. However, midlevel
   lapse rates, coupled with favorable shear profiles and modest
   instability, should support a few organized cells/clusters capable
   of producing hail.

   There is some uncertainty in intensity of initial storms in a narrow
   corridor (generally along the I-44/I-40 corridor) in central OK the
   next few hours. However, a greater severe threat, including
   potential for a few tornadoes, is expected just south and east
   across south-central/southeast OK and north TX, where more favorable
   surface-based convection is expected by mid-afternoon. While the
   tornado threat may be lower across the narrow corridor of mainly
   large hail potential across central OK, a watch may be needed in the
   next hour or so.