Severe Weather Threat 5/25-5/26, 2024

[Clancy]

Real talk though, I can't say I trust this to be either a bust or a full-blown outbreak. If you're in the Plains, feel like it's a no-brainer to be better safe than sorry. Not really putting any stock into the CAMs at this point, but 12Z NAM seems to show what could happen on the worse end of things.

 

[TornadoFan]

Yeesh.

 

[jiharris0220]

This is the difference between “bust” or boom. How moist will the dry line in central Oklahoma be?

 

[Tempestas Tonitrua]

Trey seems to think the biggest limiting factor isn’t moisture, but the convection that fires up in Northwest Texas that sends left splitting cells into Oklahoma sapping the environment. All CAMs are locked in on this convection firing in NW Texas early.

 

[Evan]

I'd be a lot more scared to be under a moderate risk in Oklahoma than a high risk.

 

[Jellyroll]

I do find it of some interest the WPC is forecasting a squall line developing by midnight.

 

[Clancy]

In Southeastern CONUS news, a WW may be required for storms in SE AL and SW GA. Upgrade to Slight Risk by 1630Z.

 

[Casuarina Head]

What’s interesting is that the nam has a far better handling on current dew points than the hrrr.
View attachment 27737View attachment 27738View attachment 27739

So dew points closer to the dry line are currently verifying a bit higher than forecast by most guidance?

 

[jiharris0220]

So dew points closer to the dry line are currently verifying a bit higher than forecast by most guidance?

Yes actually, although I’m waiting to see how much they dry off if at all when day time heating sets in.

 

[Tempestas Tonitrua]

So dew points closer to the dry line are currently verifying a bit higher than forecast by most guidance?

1-hour Dewpoint Temperature Change | Mesonet

www.mesonet.org

Norman is up +12 over 3 hours. Moisture is starting to advect in, we will just have to see if it’s enough to have the LCLs/LFCs at the optimal height. However, I’m really leaning towards Trey’s “caveat” in the NW Texas convection going off too early with the left splitters. Every model now on each run has zeroed in on that solution.

 

[Casuarina Head]

1-hour Dewpoint Temperature Change | Mesonet

www.mesonet.org

Norman is up +12 over 3 hours. Moisture is starting to advect in, we will just have to see if it’s enough to have the LCLs/LFCs at the optimal height. However, I’m really leaning towards Trey’s “caveat” in the NW Texas convection going off too early with the left splitters. Every model now on each run has zeroed in on that solution.

Why doesn’t that seem to prevent an outbreak over OK on the 12Z NAM? Is there a technical explanation?

 

[Kds86z]

1-hour Dewpoint Temperature Change | Mesonet

www.mesonet.org

Norman is up +12 over 3 hours. Moisture is starting to advect in, we will just have to see if it’s enough to have the LCLs/LFCs at the optimal height. However, I’m really leaning towards Trey’s “caveat” in the NW Texas convection going off too early with the left splitters. Every model now on each run has zeroed in on that solution.

So Trey thinks nothing gonna happen?

 

[Shakespeare 2016]

1-hour Dewpoint Temperature Change | Mesonet

www.mesonet.org

Norman is up +12 over 3 hours. Moisture is starting to advect in, we will just have to see if it’s enough to have the LCLs/LFCs at the optimal height. However, I’m really leaning towards Trey’s “caveat” in the NW Texas convection going off too early with the left splitters. Every model now on each run has zeroed in on that solution.

The dewpoint in my area has jumped up 4 degrees in the past 30 min to 1 hrs, Still a large temperature dewpoint spread although. That will possibly change with time.

 

[Tanner]

So Trey thinks nothing gonna happen?

No, he just mentioned it as THE primary fail mode on the table. But it may not entirely waste the parameter space, just prevent it from reaching its ceiling.

 

[Tempestas Tonitrua]

So Trey thinks nothing gonna happen?

Why doesn’t that seem to prevent an outbreak over OK on the 12Z NAM? Is there a technical explanation?

No Trey says today is a dangerous set up. This is more looking at factors that could keep this setup from its ceiling via fail mode. Theres going to be storms and convection, no doubt. That convection could damper the parameter space. The max ceiling would be last nights 0Z HRRR.

If you look at the helicity swaths on that 12z NAM run, which we know CAMs aren’t 100% on storm placement/type, you see one major right mover streak in Oklahoma, southern Kansas, and a few in Texas. There are faint ones in SW Oklahoma

 

[Maxis_s]

This better not convect

 

[cincywx]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1134 AM CDT SAT MAY 25 2024

VALID 251630Z - 261200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
OKLAHOMA...CENTRAL AND EASTERN KANSAS...AND SOUTHWEST MISSOURI...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER SOUTHEAST
ALABAMA AND SOUTHWEST GEORGIA...

..SUMMARY

AN OUTBREAK OF SEVERE THUNDERSTORMS IS POSSIBLE FROM LATE AFTERNOON
INTO TONIGHT OVER PARTS OF THE CENTRAL AND SOUTHERN PLAINS. A FEW
LONG-LIVED SUPERCELLS CAPABLE OF INTENSE TORNADOES MAY OCCUR. GIANT
HAIL AND DESTRUCTIVE WIND GUSTS ARE ALSO EXPECTED.

..CENTRAL/SOUTHERN PLAINS

OVERALL, LITTLE CHANGE WAS MADE TO THE ONGOING OUTLOOK WITH THIS
UPDATE, WITH THE PRIMARY CHANGE BEING AN EASTWARD EXPANSION OF THE
ENHANCED/LEVEL 3 RISK OVER PORTIONS OF NORTH TEXAS BASED ON THE 12Z
HREF GUIDANCE.

STRONG LOW-LEVEL MOISTURE ADVECTION CONTINUES ACROSS NORTHWEST
TX/SOUTHERN OK AT 16Z, AND THIS TREND IS EXPECTED TO CONTINUE AND
EXPAND NORTH INTO SOUTHERN KS WITH TIME. STRONG DIURNAL HEATING AMID
A RAPIDLY MOISTENING BOUNDARY LAYER AND STEEP MID-LEVEL LAPSE RATES
WILL YIELD STRONG/EXTREME MLCAPE THIS AFTERNOON ALONG AND EAST OF
THE DRYLINE.

INITIAL SUPERCELL DEVELOPMENT IS ANTICIPATED LATE THIS AFTERNOON
ACROSS NORTHWEST TX, WHERE STRONG DIURNAL HEATING SHOULD CONTINUE TO
ERODE CINH. ISOLATED INTENSE SUPERCELL DEVELOPMENT IS ALSO EXPECTED
FARTHER NORTH ALONG THE DRYLINE TOWARDS 00Z ACROSS OK/SOUTHERN KS,
WHERE RAPIDLY RETURNING MOISTURE INTO A WELL-HEATED BOUNDARY LAYER
COINCIDENT WITH A STRENGTHENING LOW-LEVEL JET SHOULD CONTRIBUTE TO A
HIGH-END/ALL HAZARDS SEVERE RISK. ADDITIONAL ISOLATED SUPERCELL
DEVELOPMENT IS ALSO ANTICIPATED NEAR THE WARM FRONT ACROSS NORTHERN
KS. THE PRIMARY UNCERTAINTY REMAINS STORM COVERAGE, WITH 12Z
HIGH-RES GUIDANCE CONTINUING TO EXHIBIT A RANGE OF SOLUTIONS. AS
MID-LEVEL FLOW INCREASES AND A SHORTWAVE TROUGH APPROACHES, AN
EXTREMELY FAVORABLE THERMODYNAMIC AND KINEMATIC ENVIRONMENT IS
EXPECTED TO BE IN PLACE ACROSS THE ENHANCED/MODERATE RISK AREAS FROM
LATE AFTERNOON INTO TONIGHT. THE RISK FOR STRONG/INTENSE TORNADOES,
VERY LARGE TO GIANT HAIL, AND SIGNIFICANT SEVERE WINDS REMAINS
EVIDENT.

..SOUTHEAST

RAPID DIURNAL HEATING OF A MOIST LOW-LEVEL AIR MASS IS OCCURRING
DOWNSTREAM OF ONGOING CONVECTION, AND TEMPERATURES HAVE WARMED WELL
INTO THE 80S AS OF 16Z. STRONG THUNDERSTORMS OVER SOUTHEAST AL ARE
EXPECTED TO CONTINUE MOVING SOUTHEAST WITHIN A
MODERATELY-SHEARED/NORTHWEST FLOW ENVIRONMENT AND BE CAPABLE OF
STRONG/POSSIBLY DAMAGING GUSTS AND SEVERE HAIL. A SMALL
SLIGHT/LEVEL 2 RISK HAS BEEN INTRODUCED WITH THIS OUTLOOK, WHERE THE
MORE FAVORABLE OVERLAP OF 35 KTS OF NORTHWESTERLY EFFECTIVE SHEAR
AND MODERATE/STRONG INSTABILITY WILL EXIST.

..LOWER GREAT LAKES/UPPER OHIO VALLEY

WIDELY SCATTERED TO SCATTERED THUNDERSTORMS ARE EXPECTED NEAR THE
COLD FRONT THIS AFTERNOON, AND ALONG A NEARLY PARALLEL, PREFRONTAL
TROUGH/CONVERGENCE ZONE. STORMS SHOULD MOVE EASTWARD/SOUTHEAST AND
PERSIST INTO EARLY EVENING.

ASIDE FROM LIFT ALONG THOSE BOUNDARIES, ACTIVITY WILL BE SUPPORTED
BY DIURNALLY WEAKENED MLCINH, WITH SURFACE DEWPOINTS IN THE UPPER
50S TO MID 60S F CONTRIBUTING TO AROUND 1500 J/KG MLCAPE. WEAK
LOW-LEVEL FLOW AND NEARLY UNIDIRECTIONAL LOW/MIDDLE-LEVEL WIND
PROFILES WILL TEND TO LIMIT SHEAR, HOWEVER SUFFICIENT CLOUD-BEARING
LAYER SHEAR SHOULD EXIST TO SUPPORT MULTICELL STORM STRUCTURES.
DAMAGING GUSTS AND ISOLATED HAIL WILL BE POSSIBLE FROM THE
BEST-ORGANIZED CONVECTION.

..BUNTING/SQUITIERI.. 05/25/2024

not too much was changed

 

[Kds86z]

not too much was changed

Didn’t even mention caveats like former day 1

 

[Tempestas Tonitrua]

not too much was changed

Does Bunting usually do outlooks? He’s the deputy director of the SPC.

 

[jiharris0220]

not too much was changed

Honestly because there’s nothing present to change, it’s really a wait and see mode now.

Watch for the dew points near the dry line in central Oklahoma, because that’s the make or break for this event.