I just don't get it....PDS

[STurner]

Yeah Steve my post got erased too as well. It does not bother me it got erased by no means but I was just stating about the high risk as well. I thought my word usage was proper and did not use harsh words of any kind. Ellinor I also got from a nap yesterday around 1pm and saw the high risk and PDS watches and a squall line across the radar screen and also wondered if this was going to even produce strong tornadoes. The PDS tornado watch issued till 3am was also puzzling to me for it did not seem like much was happening. Even though I think SPC must have had good reasons to why they did issue them.

 

[Joey Ketcham]

I've had several calls today from people saying "i told you nothing was going to happen, it never does....they always get excited for no reason".

You will get that no matter what. I've had my own parents tell me that on big tornado outbreak days just because it didn't happen right over their head.

You simply have to remind them of 2 things:

1). We are still dealing with a relatively new science that we are still in the process of learning. That's why we have on-going field research going on to better understand why some storms produce tornadoes and others don't in environments favorable for tornadoes.

2). The whole point of a tornado watch is to alert people that the environment could support tornado development, there are no guarantees that tornadoes will happen. Tornado watches work just the way they are designed to.

 

[Brian Stertz]

I am thinking that there were several complicating factors on yesterday's set up. First of all, you had very little cooling aloft with the positively wave that seemingly grazed the edge of the warm sector. The supercells never seemed to want to get moving off the boundary and move east way from the cold air so this big caused problems IMO. This horrible cold pool that seemed to doom anything that was able to get sustained in NW Oklahoma and NE Texas Panhandle. The weak cap in warm sector was another problem as mentioned. It was far from the perfect set up but then again, it's not my game to judge as I was not sitting any forecaster hot-seat. Data was not too plentiful out in the field for me yesterday so that is my take after seeing what data I did access yesterday.

 

[Robert Dewey]

Around 150 reports of wind/hail in the MDT risk area... verified quite well.

Lack of tornadoes != bust

 

[Derek Weston]

why did I talk about high risks? ha

 

[Elinor McLennon]

When we made it to Yukon around 7:30ish and i heard the guys in Norman tell the EOC folks that threat was rapidly diminishing and then come home to hear PDS til 3am i just had to think "what the heck".
When i got home from church around 1ish and saw all the junk on radar i kept thinking maybe this is going to blow over then PDS would happen. Even though I knew the early stuff would probably wreeck the atmosphere.
I guess I'm a freak...being bummed about lack of tornadoes and the havoc they bring. Guess I need a much better attitude and possibly a new hobby.

I wouldn't want to be in the forecasters shoes and they must take alot of flack from people with my attitude I wouldn't want to have to make the final decision about watches, etc. I do respect them and realize it's not easy and it's not a perfect science.

 

[Jesse Risley]

Steve Miller's post showing the SPC high risk stats was interesting. It made me re-think my bad attitude towards SPC statements. The dang media hype is ridiculous...we're all gonna get hit by long-lived deadly tornadoes.

As has been stated before, I think you have to initially remember that the SPC doesn't forecast specifically for the chasing community. I look at it from this perspective - the parameters were certainly in place for a sustained severe weather outbreak, including some stronger tornadoes.

There are often other mitigating factors that are nearly impossible to forecast that will become an issue from time to time, as was the case yesterday.

Forecasters realized the potential for a sustained severe weather threat and alerted the public accordingly. I'm sure they hear about it quite often when it gets blown, but how often do they get thanked for being right on the money?

I really don't blame anyone for media hype, because dirty laundry sells.

 

[Mike Bennett]

I think it was the early convection due to lack of cap that made this a bust, respectively. However, with that being said I believe the SPC issued the High Risk after the early convection began and maintained it in the 2000 outlook and again in an outlook issued later in the evening.

 

[Mike Smith]

Let me offer a thought:

The objective guidance (per 14Z RUC) prior to the 1730Z 'high risk' convective outlook issuance was off-the-chart favorable for major tornadoes. CAPE 4000+j, helicities 400+, very dry air at 700mb across KS-OK (i.e., cap, little or no grunge convection). Surface temperatures were predicted to be in the mid- to upper 70's (which occurred in OK). Nice surface low and boundary.

Interestingly, the 12Z NAM yesterday was the opposite: Lots of grunge.

I have no doubt that if the RUC had been correct, yesterday would have been a very, very big day.

I, too, did not understand the PDS until 3am. But, I do understand the first PDS.

 

[Tim Vasquez]

Just as a note we also have a parallel "official" thread regarding the 4/26 activity in Target Area:
http://www.stormtrack.org/forum/showthread.php?goto=newpost&t=20421

Please use that for technical discussions of the 4/26 storms. Since this is the Beginner's Forum the discussions here should be limited to answering the poster's question about the PDS watch.

Tim

 

[Jay McCoy]

Looking at those stats the SPC is bating about .800 on high risk days so a bust now and then isnt bad overall. I dont exactly call 13 busts out of 50 high risks as "crying wolf". If they were 100% then that would mean our forcasting and understanding of tornadogenisis is perfect. We are far from that. Mother nature is still a difficult lady to understand so give the guys a break. Overall they do an excellent job. Maybe we didnt have 80 wedges chewing their way across Oklahoma but we did have a few very nice tornados right where they called for them. I for one never thought SW oklahoma was a worthy target. I had I-40 up to the kansas border picked the whole time.

I think the weak cap and earlier convection is what screwed us. BUt I do agree thney should NOT have continued the high risk in the evening update.. That made no sense except continuity of forecasts but that isnt always a good thing. I prefer accuracy over "continuity".

 

[Darrin Rasberry]

I dont exactly call 13 busts out of 50 high risks as "crying wolf".

I think the Wiki page should list June 5th of last year as a bust, since the broad 60/hatch Wind-High and the 30/hatch issued later that day didn't turn out much (although the mod risk part somewhat did for tornadoes). Schools were shut down that day across the area IIRC, and lots of other haywire things went on, but hey, it's the weather, and I agree that the batting average has done just fine.

Curiously, Craig and I realized driving home yesterday that the PDS on Sunday verified all the probabilities on the table. There were indeed two or more tornadoes, and one of them, should the reports in the thread for that day match the assessment, was EF2 or greater. The "long track" stuff ... well, not so much.

 

[Elinor McLennon]

Seems like the bigger tornadoes don't occur on days with so much cloud cover, temps around 74, 20 - 30 mph winds with gust higher than that......is that a stupid assessment for Sunday's setup in OKC?
People said it "felt" like a tornado day. Maybe out west but not here; it was a bit nippy with that wind and cloud cover.
Was it sunny and less windy when the tornado came around Roll, vici area?

 

[Jay McCoy]

Was it sunny and less windy when the tornado came around Roll, vici area?

The louds had broken and it had heated up nicely in Shamrock and the far westerrn part of oklahoma as the storms 1st fired. I cant say how warm it was in Roll before the storm got there as we got there at the same time were a bit busy shooting video and driving to notice the temp.

 

[Justin Wiley]

I think it all depends on the situation Elinor. I remember the the 4/26/91 event quite vividly. Some low-level cloudiness, mixed out by late morning, it was very warm and humid, and it was windy.

Obviously, more cloud cover usually means less instability and thus can turn potentially 'big' tornado days into nothing more than a few isolated hail/wind reports. Typically you want a nice low-level moist flow as long as the wind increases with height the higher you go in the atmosphere. So it being windy isn't necessarily a bad thing at all. It all depends on each specific setup. 74 degrees may be enough for one system that brings more colder air aloft and may not be enough for another.