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Tn Valley Severe Weather


jaxjagman
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  • 2 weeks later...

Chance for some strong storms tomorrow.

 

National Weather Service Nashville TN
325 PM CDT Sat May 8 2021

.DISCUSSION...

Consensus blended model forecast used through Monday afternoon.
Broke out a late afternoon zone grouping dealing with continued
area of showers streaming northwest to southeast across western
and southwestern portions of mid state region, This area is
expected to shift southeastward as late afternoon hours progress
and eventually move out of mid state region before the evening
hours begin.

Otherwise, not much overall change from previous forecast
reasoning. The surface front that is hanging around mid state
region will push northward as a warm front into Kentucky
overnight. This will cause the mid state to experience much
warmer and humid conditions on Sunday. From afternoon through
evening hours on Sunday some strong to severe thunderstorms
will be possible with strong to damaging winds the main concern.
Best chance for strongest convection will be for locations
approaching TN River Valley and southwest portions of mid state
approaching TN/AL Border region. During this time period also,
strong surface pressure gradient influences could cause winds to
gust to 25 to 35 MPH at times. Taking a closer look, by the
afternoon hours on Sunday, mid state will begin to see some
surface instability (>1000 J/kg) accompanied with decent shear
and rather strong lapse rates. Instability does still appear to
be a limiting factor, but it does look like mid state region will
experience just enough instability to support development of some
strong to severe thunderstorms. As mentioned above, damaging
winds will be the primary concern, but large hail, and with model
sounding PWAT`S approaching at or around 1.5 inches, heavy
downpours causing localized flooding, especially across locations
approaching TN River Valley and southwest portions of mid state
region approaching TN/AL border could occur too. Isolated tornado
formation certainly can not be ruled out either.

CIPS Model Guida (2).png

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The debris signature looked very significant on that storm, I wonder is some of it was radar noise due to the proximity to the radar site. If not, it make have produced a fairly substantial tornado. 

 

Edit; there's now confirmed damage coming out of that area 

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sounds like they didn't issue a warning until several minutes AFTER the TDS

 

and again using confusing wording like usual (never says CAPABLE of producing a tornado when radar indicated only)

but this time it just happened to be producing when they issued the default warning wording

     
* AT 511 PM CDT, DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM  
  PRODUCING A TORNADO WAS LOCATED NEAR MUNFORD, OR 9 MILES NORTH OF  
  MILLINGTON, MOVING SOUTHEAST AT 25 MPH.  
  
  HAZARD...TORNADO.  
  
  SOURCE...RADAR INDICATED ROTATION.  
  

 

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1 minute ago, janetjanet998 said:

sounds like they didn't issue a warning until several minutes AFTER the TDS

 

and again using confusing wording like usual (never says CAPABLE of producing a tornado when radar indicated only)

but this time it just happened to be producing when they issued the default warning wording

     
* AT 511 PM CDT, DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM  
  PRODUCING A TORNADO WAS LOCATED NEAR MUNFORD, OR 9 MILES NORTH OF  
  MILLINGTON, MOVING SOUTHEAST AT 25 MPH.  
  
  HAZARD...TORNADO.  
  
  SOURCE...RADAR INDICATED ROTATION.  
  

 

Not to derail the discussion, but it's not a new issue with them. Anyways, looks like it was a brief, but intense, spin up. 

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I'm glad my radar is over in Hytop. More and more I'm convinced there's a just-right distance; and, it's not necessarily super close. Of course far gives away vital accuracy, and radar holes still need to be plugged.

Back in Wichita I would often use Vance to interrogate local storms. Wichita radar is right at the airport, which is in town; therefore, the radar beam sometimes undershoots if the storm is right in town.

Memphis radar showed rotation, but not a TVS at the time of the tornado. It was a bit loose for TVS. However the next scan showed that debris in correlation coefficient. That's a confirmed tornado good as a spotter report. Was it part of ground clutter? All I can say, it was juxtaposed with the rotation. Plus old fashioned reflectivity hook and debris ball. 

Some grace is called for with the wording. It was probably the standard warning text; and by that point, they just had to get the warning out without editing ASAP.

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I'm glad my radar is over in Hytop. More and more I'm convinced there's a just-right distance; and, it's not necessarily super close. Of course far gives away vital accuracy, and radar holes still need to be plugged.
Back in Wichita I would often use Vance to interrogate local storms. Wichita radar is right at the airport, which is in town; therefore, the radar beam sometimes undershoots if the storm is right in town.
Memphis radar showed rotation, but not a TVS at the time of the tornado. It was a bit loose for TVS. However the next scan showed that debris in correlation coefficient. That's a confirmed tornado good as a spotter report. Was it part of ground clutter? All I can say, it was juxtaposed with the rotation. Plus old fashioned reflectivity hook and debris ball. 
Some grace is called for with the wording. It was probably the standard warning text; and by that point, they just had to get the warning out without editing ASAP.

The radar was acting weird on that cell. It went from signs of a hook on base to a nice tight debris ball a scan or two later. The warning “update” like 5 minutes after the warning was issued said it was confirmed by radar and a ground spotter. I think it caught them off guard.


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  • 3 weeks later...
  • 2 weeks later...

Slight Risk in the Mid South includes 5% tornado. MCV magic season. However I figure any tornadoes would be brief and perhaps low contrast. Leading edge of MCS.

Much of the 5% is also in moderate to high flood risk from WPC. Northern part is in just awful terrain where the Tennessee River curves north back into the state, and into tree-filled hills.

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Mississippi has been pummeled two days straight. Some areas have 10+ inches of rainfall and Flash Flood Emergencies posted this morning. I think MEG (Memphis NWS WFO) posted some observed rainfall charts. 

Meanwhile an MCV is in Alabama this Noon hour Thursday. Mostly cloudy ahead of it should keep things stable. Suppose I agree with SPC. General. Snooze. When's the next hurricane?

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  • 2 weeks later...

image.png.65a9c71f584e67e1bae406d2bf931e85.png

 

SUMMARY...Thunderstorms will continue to pose a risk for a few
   strong to damaging gusts through about 00Z, followed by an overall
   decrease in intensities. Due to the limited duration of remaining
   threat, a WW will probably not be necessary.

   DISCUSSION...Widely scattered to scattered thunderstorms continue
   developing in the pre-frontal warm sector across eastern TN where
   the atmosphere remains moderately unstable with up to 2000 J/kg
   MLCAPE. Latest VAD wind profile from Morristown shows unidirectional
   west southwest winds from 30-40 kt in the 2 - 6 km layer but with
   weak vertical shear. This environment is supportive of multicells
   capable of producing locally strong to damaging gusts. The primary
   threat should persist another couple of hours, but storms should
   begin a weakening trend after 00Z as the boundary layer stabilizes
   with loss of diurnal heating.
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