August 1-? Severe Weather

[Hoosier]

line still kicking

PRELIMINARY LOCAL STORM REPORT  
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL  
1206 AM CDT WED AUG 03 2011     

.TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON     
.DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE.                
..REMARKS..    

1155 PM     TSTM WND GST     RENSSELAER              40.94N 87.15W   
08/02/2011  M67 MPH          JASPER             IN   ASOS                

[snowlover2]

Got a t-storm watch until 8am now. Guess the line will hold together.

[Chicago WX]

Storms woke me up. Decent wind, a good downpour, and a very nice CG show.

[snowlord81]

Storms woke me up. Decent wind, a good downpour, and a very nice CG show.

Agree with the lightning show, kicked it out on the deck facing north for about and hour enjoying the show. Only .2 in the rain gauge though. That'll be toast by the time the sun comes up tomorrow. We need a real good soaking. My grass is brown and crunchy and all my plants have withered away. Anyways, heres to hitting 90 a few more times! BTW...This post is for you B-Rent! The storm was pretty much run of the mill.

[B-Rent]

That was a boring Tornado Warning. I highly doubt we get any damage reports out of it. New Svr out now, will how that rolls.

[B-Rent]

Agree with the lightning show, kicked it out on the deck facing north for about and hour enjoying the show. Only .2 in the rain gauge though. That'll be toast by the time the sun comes up tomorrow. We need a real good soaking. My grass is brown and crunchy and all my plants have withered away. Anyways, heres to hitting 90 a few more times! BTW...This post is for you B-Rent! The storm was pretty much run of the mill.

Seeing a very impressive lighting show here with round two. I wonder what popped this storm up. No reports yet, probably 10-20 strikes/min in Anderson.

[Gino]

Two reports of funnel clouds.

WTF are they doing.

Edit: Finally...

Keep in mind a LOT goes into the decision to issue or not issue a tornado warning. In this case, there the rotation did intensify somewhat, but never had a nice clean gate-to-gate signature that you see with supercell tornadoes. Think back to the couplets we saw with the EF1 to EF2 tornadoes in Streator, Dwight, and in Will Co a couple years back, or the 10,000 examples from earlier this year over everywhere but our area! We were getting many, many reports of funnel clouds relayed by media and called directly in by the public, and even by the Sherriff's office, but what didn't go out in an LSR and did weigh very heavily on the warning decision was the report we took from a trusted, knowledgable, trained spotter who I was on the phone with who had something like this to say,

"...You can disregard all those funnel cloud reports you're getting from that storm their bull****. I heard the ones relayed by the Sheriff and there are no funnel clouds out here. I'm looking at a ragged wall cloud with no rotation whatsoever, but there is a lot of very low hanging scud and that's probably what everyone is reporting as funnel clouds..."

"public" reports of funnel clouds, wall clouds, and shelf cloud tend to be taken with a great deal of caution by many, but can still be used if environment/radar support such reports, but in this case we had a very reliable, knowledgable spotter reporting convincingly that the funnel reports were nothing but scud and the rotation was moderate down low, though much stronger higher up.

In general, warning forecasters will tend to go with the "rule of 3", which means when you have 2 out of the following 3 saying "yes": 1) radar signature 2) meso/storm-scale environment and/or 3) spotter reports. In this case, the spotter reports were able to be discounted fairly quickly (though I'm sure still weighing the radar operator's mind somewhat), and the meso and storm scale environments were somewhat favorable for tornadoes, but the likelihood of supercells morphing into HP meant the most likely scenario would be brief/weaker tornado (that's what the mesoscale briefing I was giving the radar operators was), so while the environment was a solid NO for TORs it wasn't a YES either. Finally, after the second scan with a decent excuse for a couplet, the radar operator's comfort threshold was exceeded and he issued the warning, which was follow minutes later by the following volume scan and the "couplet" gone and left with large moderately strong at times mesocyclone.'

While their may be times that a "WTF are they doing" is well justified for WFO LOT and any WFO for that matter, in this particular case we were on top of things like stink on ****, and I believe good warning decisions were made. Before flipping out, remember that there often times is additional information, sometimes very critical information, that radar warning meteorologist is getting that may not be broadcast or sent out to the world in real time. Hope that explains the thought process somewhat. If I have downtime tomorrow night, may try and grab screen captures of this couplet and place them side-by-side with some of the EF1-EF2 tornadoes we have had in the past just to illustrate the noteworthy differences.

The warning strategy that I try to employ as much as possible is the "It's all about the meso and storm scale environments, stupid!" Rich Thompson et al have done some AWESOME work with the sig tor parameters, but presence of a supercell moving into a high sig tor environment doesn't automatically equate to tornadogenesis. In this case there was some moderate MLCINH in place, which certainly not insurmountable, does reduce a sig/long track tor risk. For me, the environment strongly dictates the caliber of radar signature needed to put our a tor. In a ****ty environment, I'm generally going to be slow to issue a TOR until radar strongly suggests its on the ground with very impressive couplet. With an extremely favorably environment, like June 5, June 7, and last Nov 23, It may not even take anything more than strong low-level convergence down low coupled with a mid-level meso before I issue a TOR. Tues evening's case was kind murky and in the middle with the environment about a 5-6 out of 10 and the radar signature about a 6/10. It wasn't a slam dunk obvious TOR to put out given the spotter reporting no rotation and no funnel clouds, but eventually the preponderance of the evidence was enough to push him over the edge.

Hope that explains some of the thought process that went into tonights decision on when to issue the TOR and hopefully more on TOR warning philosophy and strategies.

[A-L-E-K]

weigh very heavily on the warning decision was the report we took from a trusted, knowledgable, trained spotter who I was on the phone with who had something like this to say,

"...You can disregard all those funnel cloud reports you're getting from that storm their bull****. I heard the ones relayed by the Sheriff and there are no funnel clouds out here. I'm looking at a ragged wall cloud with no rotation whatsoever, but there is a lot of very low hanging scud and that's probably what everyone is reporting as funnel clouds..."

Thanks for the insight and in murky situations, the value of a trusted spotter becomes clear.

[TimChgo9]

It seems like, whenever we have a thunderstorm around here, everyone thinks they see a "funnel cloud". Or, if the storm has high winds, they assume it was a tornado that caused them.

[TimChgo9]

Thanks for the insight and in murky situations, the value of a trusted spotter becomes clear.

Trusted, and properly trained spotters are a great asset. A spotter who can report what is going on, as opposed to what they wish was happening.

[IWXwx]

Gino, thank you for taking the time to write an informative post delving into all of the issues involved in when to TOR warn. As a trained spotter and a member of the emergency management community, IWX has done a good job of teaching us the rule of 3 and how important accurate spotter information really is in making warning decisions.

[wisconsinwx]

That was a boring Tornado Warning. I highly doubt we get any damage reports out of it. New Svr out now, will how that rolls.

You want damage reports?

[TimChgo9]

That was a boring Tornado Warning. I highly doubt we get any damage reports out of it. New Svr out now, will how that rolls.

Perhaps an EF-3 ravaging a community would have made it less boring? Why stop at damage reports? Why not wish for a body count, too? After this season, and watching, and hearing about the destruction and loss of like and property, caused by tornadoes, I am beginning to find that remarks like the above are beginning to border on being offensive.

It's one thing to track the storms, and get caught up in the excitement of a weather event. I get the same way. But there is a line that shouldn't be crossed. Tornado warning with no damage reports? That's a sigh of relief, not a cause for disappointment.

[BadgerWXman]

Perhaps an EF-3 ravaging a community would have made it less boring? Why stop at damage reports? Why not wish for a body count, too? After this season, and watching, and hearing about the destruction and loss of like and property, caused by tornadoes, I am beginning to find that remarks like the above are beginning to border on being offensive.

Wrong. Some of us have careers in this field because we love really bad weather despite the fact that it causes loss of life. It's going to happen, and some years are going to be worse than others, but to pretend we're not "rooting" for a tornado sometimes to see it or follow it on radar is just silly. Notice I didn't say "rooting for a tornado to hit a populated area."

This is just the same as a doctor who loves doing surgery hoping for a patient in really bad shape to present a challenge. So please stop being overly-sensitive. I could understand if you've lost someone close and it's a sore subject, but there's a reason we do this on a private forum amongst other weather geeks.

[BadgerWXman]

Nice shot from FB.. taken over Lexington this morning as the MCS rolled through:

[TimChgo9]

Wrong. Some of us have careers in this field because we love really bad weather despite the fact that it causes loss of life. It's going to happen, and some years are going to be worse than others, but to pretend we're not "rooting" for a tornado sometimes to see it or follow it on radar is just silly. Notice I didn't say "rooting for a tornado to hit a populated area."

This is just the same as a doctor who loves doing surgery hoping for a patient in really bad shape to present a challenge. So please stop being overly-sensitive. I could understand if you've lost someone close and it's a sore subject, but there's a reason we do this on a private forum amongst other weather geeks.

I took exception to what appeared to me to be a callous, off hand, inconsiderate remark. Perhaps I responded too hastily to that remark. The last thing I want to do is start a furball over this. I should have thought twice before pressing "enter".

And you are right, it is a private forum amongst other weather geeks, of which I am one.

[wisconsinwx]

Wrong. Some of us have careers in this field because we love really bad weather despite the fact that it causes loss of life. It's going to happen, and some years are going to be worse than others, but to pretend we're not "rooting" for a tornado sometimes to see it or follow it on radar is just silly. Notice I didn't say "rooting for a tornado to hit a populated area."

This is just the same as a doctor who loves doing surgery hoping for a patient in really bad shape to present a challenge. So please stop being overly-sensitive. I could understand if you've lost someone close and it's a sore subject, but there's a reason we do this on a private forum amongst other weather geeks.

I do think there's a difference though between hoping for interesting/inclement weather like severe thunderstorms, and being disappointed b/c a tornado warning didn't bring damage reports. If I could experience a hail or windstorm and not have any damage, that would be a good thing at this point. It's the damage part that is offputting for many, I'm sure.

[Chicago Storm]

Keep in mind a LOT goes into the decision to issue or not issue a tornado warning. In this case, there the rotation did intensify somewhat, but never had a nice clean gate-to-gate signature that you see with supercell tornadoes. Think back to the couplets we saw with the EF1 to EF2 tornadoes in Streator, Dwight, and in Will Co a couple years back, or the 10,000 examples from earlier this year over everywhere but our area! We were getting many, many reports of funnel clouds relayed by media and called directly in by the public, and even by the Sherriff's office, but what didn't go out in an LSR and did weigh very heavily on the warning decision was the report we took from a trusted, knowledgable, trained spotter who I was on the phone with who had something like this to say,

"...You can disregard all those funnel cloud reports you're getting from that storm their bull****. I heard the ones relayed by the Sheriff and there are no funnel clouds out here. I'm looking at a ragged wall cloud with no rotation whatsoever, but there is a lot of very low hanging scud and that's probably what everyone is reporting as funnel clouds..."

"public" reports of funnel clouds, wall clouds, and shelf cloud tend to be taken with a great deal of caution by many, but can still be used if environment/radar support such reports, but in this case we had a very reliable, knowledgable spotter reporting convincingly that the funnel reports were nothing but scud and the rotation was moderate down low, though much stronger higher up.

In general, warning forecasters will tend to go with the "rule of 3", which means when you have 2 out of the following 3 saying "yes": 1) radar signature 2) meso/storm-scale environment and/or 3) spotter reports. In this case, the spotter reports were able to be discounted fairly quickly (though I'm sure still weighing the radar operator's mind somewhat), and the meso and storm scale environments were somewhat favorable for tornadoes, but the likelihood of supercells morphing into HP meant the most likely scenario would be brief/weaker tornado (that's what the mesoscale briefing I was giving the radar operators was), so while the environment was a solid NO for TORs it wasn't a YES either. Finally, after the second scan with a decent excuse for a couplet, the radar operator's comfort threshold was exceeded and he issued the warning, which was follow minutes later by the following volume scan and the "couplet" gone and left with large moderately strong at times mesocyclone.'

While their may be times that a "WTF are they doing" is well justified for WFO LOT and any WFO for that matter, in this particular case we were on top of things like stink on ****, and I believe good warning decisions were made. Before flipping out, remember that there often times is additional information, sometimes very critical information, that radar warning meteorologist is getting that may not be broadcast or sent out to the world in real time. Hope that explains the thought process somewhat. If I have downtime tomorrow night, may try and grab screen captures of this couplet and place them side-by-side with some of the EF1-EF2 tornadoes we have had in the past just to illustrate the noteworthy differences.

The warning strategy that I try to employ as much as possible is the "It's all about the meso and storm scale environments, stupid!" Rich Thompson et al have done some AWESOME work with the sig tor parameters, but presence of a supercell moving into a high sig tor environment doesn't automatically equate to tornadogenesis. In this case there was some moderate MLCINH in place, which certainly not insurmountable, does reduce a sig/long track tor risk. For me, the environment strongly dictates the caliber of radar signature needed to put our a tor. In a ****ty environment, I'm generally going to be slow to issue a TOR until radar strongly suggests its on the ground with very impressive couplet. With an extremely favorably environment, like June 5, June 7, and last Nov 23, It may not even take anything more than strong low-level convergence down low coupled with a mid-level meso before I issue a TOR. Tues evening's case was kind murky and in the middle with the environment about a 5-6 out of 10 and the radar signature about a 6/10. It wasn't a slam dunk obvious TOR to put out given the spotter reporting no rotation and no funnel clouds, but eventually the preponderance of the evidence was enough to push him over the edge.

Hope that explains some of the thought process that went into tonights decision on when to issue the TOR and hopefully more on TOR warning philosophy and strategies.

Well, that pretty much takes care of it then. I do know of the "rule of 3" for the issuance of a warning, so when I saw the rotation/meso at different levels, the funnel reports, and that it was in a somewhat favorable environment, I just went with it...Without knowing the full extent of what was going on, as you have brought up for us. Without knowing the full extent of the situation should we jump to say something? It depends, but in this case I was just going off what I had avaliable, not thinking of any other issues that might be taking place behind the scenes.

In no way was I going after you all as forecasters for your decision or "flipping out" for that matter...It was more of me sitting here looking at things debating if I should head west on a local chase, seeing everything and having a "WTF moment"...Pretty much thinking, "Well hey, that's interesting".

Thanks for taking the time to stop in with more info along with the thought process and other things that went into the warning decision. Hell, one day when and if I get through the last two years or so of college (****ing math), I might be in the same position as you were last evening trying to figure out what to do in that situation.

[Hoosier]

This is above the standard measuring height but still impressive.

PRELIMINARY LOCAL STORM REPORT...CORRECTED  
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL  
149 PM CDT WED AUG 03 2011     

.TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON     
.DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE.                
..REMARKS..    

1039 PM     TSTM WND GST     GARY                    41.60N 87.34W   
08/02/2011  M96.00 MPH       LAKE               IN   AWOS                            

DELAYED REPORT FROM GARY AIRPORT. 83 KNOT GUST MEASURED WITH TOWER ANEMOMETER AT ABOUT 50 FEET ABOVE GROUND. 
SEALS BLOWN OUT OF NORTHWEST FACING WINDOWS IN TOWER...ALLOWING WATER TO GET IN. INDUSTRIAL SIZE TRASH BIN BLOWN 
OVER 50 FEET AWAY. AIRPLANE STAIRS WITH BRAKES APPLIED BLOWN AN ESTIMATED 800 FEET...INCLUDING 150 FEET INTO GRASS. 
TREES WERE ALSO BLOWN DOWN AROUND TOWER AND POWER WAS KNOCKED OUT.    

[Hoosier]

more from Gary

PRELIMINARY LOCAL STORM REPORT  
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL  
222 PM CDT WED AUG 03 2011     

.TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON     
.DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE.                
..REMARKS..    

1040 PM     TSTM WND DMG     GARY                    41.60N 87.34W   
08/02/2011                   LAKE               IN   LAW ENFORCEMENT                 

DELAYED REPORT. MANY TREES AND TREE LIMBS DOWN.TREES AND LIMBS BLOWN ONTO POWER LINES. 
MULTIPLE LARGE TREES DOWN...SOME BLOCKING STREETS.  

[Hoosier]

Just doing a *really* quick review of base velocity at the time that Gary got slammed, there's definitely a pocket of stronger velocities that went north of I-80. But it appears that the strongest winds actually occurred farther back within the line and not at the leading edge.

[cyclone77]

Just doing a *really* quick review of base velocity at the time that Gary got slammed, there's definitely a pocket of stronger velocities that went north of I-80. But it appears that the strongest winds actually occurred farther back within the line and not at the leading edge.

It's still too early to load the level II archive data from NCDC, but you can see a few interesting features on the RAP UCAR basic radar. From the LOT radar you can see a large pocket of strong winds immediately following the leading edge of the forward propagating apex. Could be from a rear inflow jet, or a combination of that and the maturing cold pool. Either way whatever it was seemed to be accelerating the whole line in that area. Scanning from the IWX radar it looks like there was a meso-vortex right on the leading edge of the line right over Gary. It's pretty subtle, but you can definitely see it. In a day or two I'll be able to load the level II data from NCDC into GR2A and should get a much better look at everything.

[L.B. LaForce]

It's still too early to load the level II archive data from NCDC, but you can see a few interesting features on the RAP UCAR basic radar. From the LOT radar you can see a large pocket of strong winds immediately following the leading edge of the forward propagating apex. Could be from a rear inflow jet, or a combination of that and the maturing cold pool. Either way whatever it was seemed to be accelerating the whole line in that area. Scanning from the IWX radar it looks like there was a meso-vortex right on the leading edge of the line right over Gary. It's pretty subtle, but you can definitely see it. In a day or two I'll be able to load the level II data from NCDC into GR2A and should get a much better look at everything.

What time are you looking at? You can still get the data from the iastate mesonet page.

http://mesonet.agron.iastate.edu/data/nexrd2/raw/KLOT/

[B-Rent]

Perhaps an EF-3 ravaging a community would have made it less boring? Why stop at damage reports? Why not wish for a body count, too? After this season, and watching, and hearing about the destruction and loss of like and property, caused by tornadoes, I am beginning to find that remarks like the above are beginning to border on being offensive.

It's one thing to track the storms, and get caught up in the excitement of a weather event. I get the same way. But there is a line that shouldn't be crossed. Tornado warning with no damage reports? That's a sigh of relief, not a cause for disappointment.

Boring as in un-eventful and not verified. Boring as in it caused disruption that wasn't needed in hindsight. Boring as in when I am sitting at work and a tornado warning comes in usually I am working my ass off, and not just sitting twiddling my thumbs. If you knew me you would know I wouldn't wish damage, destruction, injuries, or death on anyone.

Thanks for the snide remark though.

[cyclone77]

What time are you looking at? You can still get the data from the iastate mesonet page.

http://mesonet.agron...exrd2/raw/KLOT/

Ahhh I didn't know about the site you linked. Nice.

I always use this one, but the data isn't available for a day or two after the event.

http://www.ncdc.noaa.gov/nexradinv/

[cyclone77]

Scanning from the LOT radar, it shows a small area of 70kts at about 2000ft AGL just north of Gary. Hoosier was correct, it appears the strongest winds were behind the leading edge of the line back in the main downdraft area.

[cyclone77]

Just checked the IWX radar data on GR2 for that Gary storm, and unfortunately there was a ton of range folding in that area, so wind velocity data wasn't very good.

[andyhb]

Is it just me, or is there potential into next week in the Central/Southern Plains into the Ozarks? Both the ECMWF and GFS seem to develop a series of impulses around the base of the large and amplifying Hudson's Bay trough, with potentially enhanced shear and good instability.

[andyhb]

Here we go, Day 4 (And a rather large one at that). Perhaps we could start a new thread for the 6th/7th onward...

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0353 AM CDT FRI AUG 05 2011

VALID 081200Z - 131200Z

...DISCUSSION...

MODEL CONSENSUS IS THAT UPPER RIDGE WILL GRADUALLY BREAK DOWN OVER

THE ERN HALF OF THE U.S. AS SERIES OF IMPULSES DROP SEWD THROUGH SRN

CANADA AND THE OH VALLEY RESULTING IN A AMPLIFICATION OF LARGE SCALE

UPPER TROUGH THROUGH THE PERIOD.

DAY 4...LEAD VORT MAX WILL CONTINUE THROUGH REMAINDER OF THE GREAT

LAKES AND NERN STATES WHILE SECONDARY SHORTWAVE TROUGH DROPS SEWD

INTO THE NRN/CNTRL PLAINS AND UPPER MS VALLEY. PRIMARY SEVERE THREAT

MONDAY IS EXPECTED TO FROM THE CNTRL PLAINS AND MID MS VALLEY IN

VICINITY OF NW-SE ORIENTED BAROCLINIC ZONE WHERE STRONG INSTABILITY

WILL EXIST AND WHERE VERTICAL SHEAR WILL INCREASE IN ASSOCIATION

WITH SEWD ADVANCING SHORTWAVE TROUGH. WHILE MESOSCALE DETAILS AND

UNCERTAINTIES SUCH AS LOCATION OF OUTFLOW BOUNDARIES AND ANY ONGOING

CONVECTION REMAIN...STORMS WILL LIKELY REDEVELOP SOMEWHERE IN

GENERAL VICINITY OF THE BAROCLINIC ZONE WHERE THE SHEAR/INSTABILITY

SPACE WILL LIKELY BECOME FAVORABLE FOR AN ORGANIZED SEVERE EVENT.

OTHER STRONG TO SEVERE STORMS WILL BE POSSIBLE FARTHER NORTH FROM

THE ERN DAKOTAS INTO THE UPPER MS VALLEY ALONG SEWD ADVANCING FRONT

AS WELL AS OVER A PORTION OF THE NERN STATES.

BEYOND DAY 4...PREDICTABILITY IS TOO LOW TO INTRODUCE A RISK AREA.

..DIAL.. 08/05/2011

[hm8]

DTX has been talking up the potential here on Sunday for a couple AFDs now...slight risk for all of lower MI on the new day 3.