General Weather Discussion - May 2019

[Anonymous.]

We should see early morning convection come out across the panhandle into W and SW OK early Monday morning. Models having tough time in regards to how much lingering convection will affect the forecast area across OK. It appears we should have near-immediate clearing of rain and clouds across SW and toward C OK. However, models are notoriously bad at forecasting coldpools leftover from large areas of previous convection.

Once heating builds back in the area, destabilization will rapidly build in with strong southerly winds and sunshine. A sharp dryline is expected to become established very near the OK/TX PH border. A round of storms should develop here or slightly east of here. These will be the most dangerous storms as initial cells could move east off the boundary and feast on the destable airmass ahead. Large hail and tornadoes will be the main threat for any cells that remain isolated. If too many storms form at once, we could have clusters of cells that interrupt each other versus a more dangerous scenario of 3-4 discrete supercells.

More storms will fire later on off to the west and a very long line of convection will sweep across the region late overnight. If this occurs, the main threat will be damaging winds and flooding, outside chance at weaker tornadoes along the front of the line like we usually see.

Here is snapshot from NAM showing the initial dryline development in the afternoon after morning convection moves off to the N/NE.

[OSUPeterson]

Mid del schools just cancelled school for tomorrow...

[BB37]

Mid del schools just cancelled school for tomorrow...

OKCPS and Moore have also.

[SoonerDave]

OKCPS and Moore have also.

Beat me to it.

There was rumbling late Friday that Moore might cancel Monday's classes.

[d-usa]

Deer Creek joined the list.

[jn1780]

Not really surprised at all that schools closed. No one wants to be caught off guard again.

[d-usa]

I’m sure most, if not all, are in their last week with days to spare. No point risking early dismissals or getting hit with severe weather during commute time.

[Pete]

It seems most high schools held their commencement over the weekend so I would bet almost everyone is through their final testing.

[jn1780]

When I was a senior 15 years ago we had to take finals even after graduating. I thought it was crazy. You just get a diploma holder. I bet it makes not passing that much more painful.

[LordGerald]

When I was a senior 15 years ago we had to take finals even after graduating. I thought it was crazy. You just get a diploma holder. I bet it makes not passing that much more painful.

Most schools started moving commencement before finals years ago to prevent seniors from graduation night shenanigans. I graduated HS in 1983, and there were several people in my class that walked across the stage with nothing on but their gown. When we threw our hats, we threw them at the stage, trying to peg the vice-principal. Morterboards are deadly if thrown on target. You can blame my generation for the change.

[Bunty]

FLOOD WATCH
Areas Affected:
Alfalfa - Atoka - Beckham - Blaine - Bryan - Caddo - Canadian - Carter - Cleveland - Coal - Comanche - Cotton - Custer - Dewey - Ellis - Garfield - Garvin - Grady - Grant - Greer - Harmon - Harper - Hughes - Jackson - Jefferson - Johnston - Kay - Kingfisher - Kiowa - Lincoln - Logan - Love - Major - Marshall - McClain - Murray - Noble - Oklahoma - Payne - Pontotoc - Pottawatomie - Roger Mills - Seminole - Stephens - Tillman - Was hita - Woods - Woodward
Effective: Thu, 5/23 7:00am Updated: Sun, 5/19 7:54pm Urgency: Future
Expires: Thu, 5/23 7:00pm Severity: Moderate Certainty: Possible

Details:

...Significant Flooding Possible Monday into Tuesday...
.Thunderstorms with heavy rainfall will be likely Monday through
early Tuesday, especially from western and central Oklahoma into
northern parts of Oklahoma. While western north Texas and
southeast Oklahoma may not see as long of a duration of heavy
rain, even brief heavy rainfall late Monday and early Tuesday may
lead to flooding and flash flooding.

...FLOOD WATCH IN EFFECT FROM MONDAY MORNING THROUGH TUESDAY
AFTERNOON...
The National Weather Service in Norman has issued a
* From Monday morning through Tuesday morning.
* Significant flooding from heavy rainfall will be possible,
especially across western, central, and northern Oklahoma.
Precautionary/preparedness actions...
A Flood Watch means there is a potential for flooding based on
current forecasts.
You should monitor later forecasts and be alert for possible
Flood Warnings. Those living in areas prone to flooding should be
prepared to take action should flooding develop.

Counties in dark green affected:

[bchris02]

Tomorrow is looking like an absolute worst case tornado situation for the OKC area.

[SoonerDave]

Tomorrow is looking like an absolute worst case tornado situation for the OKC area.

I think that's a tad extreme. The most recent regions put OKC at the east edge of the highest warning area...no, not ideal, have to take it seriously, but painting it quite that morbidly is a little over the top.

[bchris02]

I think that's a tad extreme. The most recent regions put OKC at the east edge of the highest warning area...no, not ideal, have to take it seriously, but painting it quite that morbidly is a little over the top.

I'm going by the most recent HRRR for tomorrow and what people I know who are chasers are saying. It's really going to depend on where the warm front sets up but if it stalls just north of the metro in the late afternoon, this is going to be one of those days everyone will talk about for decades.

[SoonerDave]

I'm going by the most recent HRRR for tomorrow and what people I know who are chasers are saying. It's really going to depend on where the warm front sets up but if it stalls just north of the metro in the late afternoon, this is going to be one of those days everyone will talk about for decades.

And if it doesn't, it won't be. All the grisly, forboding language helps nothing.

[d-usa]

Explicit language helps to raise awareness though. We don’t need “you will die” language, but “the ingredients for a worst case scenario are there so be prepared” is okay with me.

[jonny d]

Explicit language helps to raise awareness though. We don’t need “you will die” language, but “the ingredients for a worst case scenario are there so be prepared” is okay with me.

Nope. Crying wolf hasn't helped anyone. The meteorologists have been wrong so many times, that forcing it down our throats with such gusto is kind of overkill.

[jn1780]

I think that's a tad extreme. The most recent regions put OKC at the east edge of the highest warning area...no, not ideal, have to take it seriously, but painting it quite that morbidly is a little over the top.

Not going to comment on what bchris said, but it should be pointed out that storms dont really care about lines drawn on the map. Plus, in theory the probabilities all within a moderate risk area are the same. Cant really think of it as bullseye where being further away from it you win although and some cases that applies.

That said I wouldn't be surprise if this evolves into a MCS mess with storms competing with each other by the time they get to the Metro area.

[jn1780]

Nope. Crying wolf hasn't helped anyone. The meteorologists have been wrong so many times, that forcing it down our throats with such gusto is kind of overkill.

What exactly do you want them to say? At least when it comes to the NWS they have a set of predetermined criteria based on historical data to quantify a risk. People who knows nothing about weather forecasting need to have this simplified down in some way. Not fault computers models cant predict everything with 100 percent accuracy.

Let's face it. May 20th 2013, was slightly under predicted in initial risk. At least officially.

[bchris02]

Nope. Crying wolf hasn't helped anyone. The meteorologists have been wrong so many times, that forcing it down our throats with such gusto is kind of overkill.

This is a unique event. Many people are saying they've never seen anything quite like it. However, the thing about these high-end events is if just one thing doesn't set up the right way it could change the entire outcome. The ingredients are there though for a nightmare scenario tomorrow.

As jn1780 said, the entire thing turning into an MCS mess by the time it gets to the metro is a possibility. If that happens, flooding will be the primary risk and not tornadoes. Worst case is warm front stalled out just north of the metro and numerous discreet supercells moving northeast along it ahead of the main MCS.

[SoonerDave]

The ingredients are there though for a nightmare scenario tomorrow.

That's precisely the kind of language that isn't helpful. "Nightmare scenario" isn't scientific or meterorological or really anything but inflammatory, and one of the reasons ol Venture started this forum many years back was to counter it. Anon does a great job of filling Venture's shoes these days and I just don't favor invoking the hareum-scareum language here.

Yes, tomorrow is a concerning setup, but all any of us can do is be informed and prepared. Not scared.

[BG918]

This is a unique event. Many people are saying they've never seen anything quite like it. However, the thing about these high-end events is if just one thing doesn't set up the right way it could change the entire outcome. The ingredients are there though for a nightmare scenario tomorrow.

As jn1780 said, the entire thing turning into an MCS mess by the time it gets to the metro is a possibility. If that happens, flooding will be the primary risk and not tornadoes. Worst case is warm front stalled out just north of the metro and numerous discreet supercells moving northeast along it ahead of the main MCS.

The MCS scenario looks a lot more likely than discreet supercells, at least in central/eastern OK. Then the threat of serious flash flooding is a real possibility which is much more dangerous than tornadoes as it affects way more people. Rivers are also running high so any more inflow could cause issues there as well.

[Slimjim]

What’s MCS

[Teo9969]

What’s MCS

A mesoscale convective system (MCS) is a complex of thunderstorms that becomes organized on a scale larger than the individual thunderstorms but smaller than extratropical cyclones, and normally persists for several hours or more.

So basically a mini hurricane?

[SoonerDave]

So basically a mini hurricane?

Some MCS systems can exhibit radar and satellite characteristics similar to that of a hurricane, but the broader term is meant to convey a very large region of storm-related atmospheric "lift." "Mesoscale convective system" taken literally means "very large scale uplift", and can happen when close, discrete storms start to merge.