May 2024 - General Weather Discussion

[stratosphere]

Friendly reminder not to panic over a single model run (in this case, the 12z HRRR), but rather, treat it as an example of the high-end potential that tomorrow has and a reminder to stay weather aware as a result. Would guess that the SPC will extend the 10% hatched tornado risk into the Metro at the 12:30 p.m. Day Two update. Don’t think they’ll upgrade past that at this time as the potential for a cap bust is still very apparent (for example, the 12z 3km NAM doesn’t convect over the state at all).

Also, as an FYI, this evening will be absolutely gorgeous and possibly one of our final time periods without humidity until autumn. So, it’ll be a great opportunity to get outside if you’re not a fan of the summer heat.

I went for a walk this morning around 8 and it was incredibly humid - are you saying the humidity will decrease as the day goes on?

[Anonymous.]

I went for a walk this morning around 8 and it was incredibly humid - are you saying the humidity will decrease as the day goes on?

Yes, the front is just to the NW of OKC currently. NW winds will sweep down and bring in dryer air this afternoon and evening.

[C_M_25]

Looks to be like a cap is going to be in place tomorrow. Strong atmospheric instability in place however. Seems similar to our other setups this year. Some models struggling to break the cap and others are showing one or two storms. The dry line should be set up west of okc but it looks like storm initiation could be right on top of okc and points east. If the cap breaks, it could be a very busy day.

[jn1780]

I think the airport has gone well over 6 months without an inch of rain. With a switch to La Nina coming, OKC needs to stockpile rain for the dry summer and fall coming up.

No

There are products besides the drought monitor out there......

https://www.mesonet.org/weather/rain...ation?ref=1210

https://www.mesonet.org/weather/rain...ation?ref=1210

I don't even think it works that way. Only so much stockpiling life and the Earth can do if its already at 'normal'.

[PoliSciGuy]

Day 2 MDT issued, includes the entire metro area

https://x.com/NWSSPC/status/1794062551107694799

15% hatched tornado risk for the metro too

[jn1780]

From the Day 2 Discussion

.Central and Southern Plains...
Much of the day will be void of storms as the warm sector develops.
Rapid changes in the environment are expected during the late
afternoon and evening, as the approaching upper wave interacts with
the uncapped air mass. Storms are likely to form first across
western NE into western KS near the developing cold front and
surface low, an beneath the strongest cooling aloft. Strengthening
southwest flow behind the dryline and deep mixed layers should
easily support development after 21Z in this area. Very large hail
is likely initially, with increasing tornado threat with long-lived
supercells as they evolve eastward through the evening. Long-tracked
and violent tornadoes will be possible as the low-level jet
increases during the evening, while maintaining a very moist and
unstable boundary layer. Extreme hail over 4.00 inches is expected
with such strong instability and impressive mid to upper level wind
speeds.

With time, storms are expected to merge into a severe MCS, possibly
with corridors of extreme wind damage, as it proceeds into eastern
KS and far western MO late.

Farther south along the dryline and within the open warm sector
across OK and into TX, overall large-scale lift will be less than
points north. However, at least isolated, very large supercells
capable of destructive tornadoes and extreme hail will be possible
with storms that form late in the day and evening and move across
western and central OK and pars of northern TX.

Aside from the steeper lapse rate environment near the dryline,
mesoscale conditions will need to be closely monitored for low-level
confluence lines within the deepening moist sector east of the
dryline. The cap will not be particularly strong or high off the
ground (low LFC). Given mid 70s F dewpoints and expected late
initiation, this may be a plausible scenario from northwest TX into
central OK. Only reduced confidence in total storm coverage is
precluding a High Risk at this time.

[stratosphere]

Yes, the front is just to the NW of OKC currently. NW winds will sweep down and bring in dryer air this afternoon and evening.

I went to lunch earlier and noticed the change as the winds were blowing a bit and the air was cooler and pleasant

[John1744]

Damn that’s another pretty strongly worded discussion. Seen too many of these this year.

The tornados seems weird this year. The low level jet at night has really spooked me a couple times with what it’s done to some storms.

[warreng88]

Ok, question for the experts: I am planning to go to Tulsa Saturday afternoon (around 2) and come back around 8. Is the threat in the turnpike area or further east? Trying to see if we need to change the trip to Sunday.

[PoliSciGuy]

Ok, question for the experts: I am planning to go to Tulsa Saturday afternoon (around 2) and come back around 8. Is the threat in the turnpike area or further east? Trying to see if we need to change the trip to Sunday.

The threat are supercells that will form west of OKC proper, move across the I-35 corridor and then persist into Tulsa. Storms probably get to the metro around 7pm or so and then keep trucking west. I personally am planning to not be on the roads after 5pm tomorrow. Here's the NWS Norman tweet referencing the timeline: https://x.com/NWSNorman/status/1794067300930253257

[Mr. Blue Sky]

The threat are supercells that will form west of OKC proper, move across the I-35 corridor and then persist into Tulsa. Storms probably get to the metro around 7pm or so and then keep trucking west. I personally am planning to not be on the roads after 5pm tomorrow. Here's the NWS Norman tweet referencing the timeline: https://x.com/NWSNorman/status/1794067300930253257

No reason for people here to read this as, “Don’t be on the roads,” tomorrow. He’s saying that he, personally, won’t be on the roads after 5pm tomorrow. The reality is that the brand new forecast from NWS shows an 80% chance of no storms at all tomorrow evening, severe or otherwise.

[Ginkasa]

No reason for people here to read this as, “Don’t be on the roads,” tomorrow. He’s saying that he, personally, won’t be on the roads after 5pm tomorrow. The reality is that the brand new forecast from NWS shows an 80% chance of no storms at all tomorrow evening, severe or otherwise.

They say 20% chance. Does that mean 20% there will be anything at all or anywhere or 20% chance that something would impact a specific area?

I always get that confused.

[Mr. Blue Sky]

They say 20% chance. Does that mean 20% there will be anything at all or anywhere or 20% chance that something would impact a specific area?

I always get that confused.

It means probability over the entire forecast area over the defined forecast time.

https://www.weather.gov/media/pah/WeatherEducation/pop.pdf
Hope that ^^^^ helps.

[PoliSciGuy]

Yes, the majority of folks will likely not see a drop of rain, but for folks in the line of the storms that do form, tomorrow is going to be really serious.

[Mr. Blue Sky]

Yes, the majority of folks will likely not see a drop of rain, but for folks in the line of the storms that do form, tomorrow is going to be really serious.

It’s understandable, many people confuse this, but as I explained to Ginkasa, that’s not how it works. It’s not 20% of the people will be hit by storms and so, for those 20% it could be serious. Please read my post right before yours.

Edit: In short — the prediction by NWS is that there is a 20% chance of thunderstorms tomorrow evening for anywhere within the forecast area (Oklahoma City) at any time during the forecast window (evening).

[PoliSciGuy]

It’s understandable, many people confuse this, but as I explained to Ginkasa, that’s not how it works. It’s not 20% of the people will be hit by storms and so, for those 20% it could be serious. Please read my post right before yours.

I did, thanks. My statement wasn't incorrect, and it's in line with what other mets are saying: https://x.com/tornadopayne/status/1794118302177886598

[floyd the barber]

Yeah I really would not want to be on the turnpike when a tornado is imminent. There is really nothing out there.

[Mr. Blue Sky]

I did, thanks. My statement wasn't incorrect, and it's in line with what other mets are saying: https://x.com/tornadopayne/status/1794118302177886598

Well, no, David never mentions the 20% probability. It goes without saying that being in the way of any storms that do (as in might) develop could be serious. But the chance of that happening is 20% for anybody and everybody within the entire forecast zone. So, as to your response to my original post, it was incorrect and misinformation. A 20% chance means a 20% chance. Your response to me is clear you believe the widespread misinformation about meteorological percentages.

[Mississippi Blues]

Well, no, David never mentions the 20% probability. It goes without saying that being in the way of any storms that do (as in might) develop could be serious. But the chance of that happening is 20% for anybody and everybody within the entire forecast zone. So, as to your response to my original post, it was incorrect and misinformation. A 20% chance means a 20% chance. Your response to me is clear you believe the widespread misinformation about meteorological percentages.

The screenshot you posted was for Oklahoma City. The post you originally responded to was an answer to a question about being on the turnpike at 2pm and 8pm between Oklahoma City and Tulsa.

[Mr. Blue Sky]

The screenshot you posted was for Oklahoma City. The post you originally responded to was an answer to a question about being on the turnpike at 2pm and 8pm between Oklahoma City and Tulsa.

What?!? MB, that doesn’t matter — it was PoliSciGuy’s reply (which used an OKC screenshot) that I responded to. Whether it was the Tulsa (40%) or OKC (20%) forecast he was responding to, it doesn’t matter, the math re: the misapplication of percentages is the same. Again, I feel like I’m having to defend facts and the widespread misuse when it comes to meteorological percentages. Ginkasa had kindly asked which application of percentages was correct, and I explained and after that PoliSciGuy was insisting he was correct. Would somebody else help me out here? I shouldn’t be having to explain this again.

[Video Expert]

What?!? MB, that doesn’t matter — it was PoliSciGuy’s reply (which used an OKC screenshot) that I responded to. Whether it was the Tulsa (40%) or OKC (20%) forecast he was responding to, it doesn’t matter, the math re: the misapplication of percentages is the same. Again, I feel like I’m having to defend facts and the widespread misuse when it comes to meteorological percentages. Ginkasa had kindly asked which application of percentages was correct, and I explained and after that PoliSciGuy was insisting he was correct. Would somebody else help me out here? I shouldn’t be having to explain this again.

Yeah this is getting a little silly. A 20% chance of Thunderstorms means a 20% chance in the given forecast area. It does not mean 20% WILL see storms and 80% WILL NOT. In fact, there could be a total of ZERO storms in the forecast area that had the 20% chance. Or just about everyone could see storms in the 20% forecast area. It simply means at this particular time, there's a 1 out of 5 chance someone in the 20% zone will encounter a thunderstorm in one specific location within that area during that specific forecast period.

[Mr. Blue Sky]

Yeah this is getting a little silly. A 20% chance of Thunderstorms means a 20% chance in the given forecast area. It does not mean 20% WILL see storms and 80% WILL NOT. In fact, there could be a total of ZERO storms in the forecast area that had the 20% chance. Or just about everyone could see storms in the 20% forecast area. It simply means at this particular time, there's a 1 out of 5 chance someone in the 20% zone will encounter a thunderstorm in one specific location within that area during that specific forecast period.

Thank you, and you explained it better than me!

[jn1780]

And that 20% could turn into 30 or 40% if forecasters look at the data in the early morning and see that the cap is much more breakable than expected. Really just have to wait and see.

[PoliSciGuy]

The latest HRRR run came in, printed tornadic supercells all along the I-35 corridor from Wichita to Ardmore, prompting an SPC forecaster to tweet this:

https://x.com/TwisterKidMedia/status...79842549985479

I think we see a high by the 1am outlook

[jn1780]

The latest HRRR run came in, printed tornadic supercells all along the I-35 corridor from Wichita to Ardmore, prompting an SPC forecaster to tweet this:

https://x.com/TwisterKidMedia/status...79842549985479

I think we see a high by the 1am outlook

And there you go. I would expect the point forecast percentages to go up to.