March 27-28 Severe Storms

[jaxjagman]

Figured i'd run with it.Could have actually extended yesterdays with this because it's still part of that storm with the boundary lifting Northward.Some uncertainty still how far the warm front will lift and where it will be,but every model i have seen shows it going into the lower OV at least.

 

  Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1224 PM CDT Fri Mar 26 2021

   Valid 271200Z - 281200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER A PORTION
   OF THE LOWER MISSISSIPPI INTO THE TENNESSEE VALLEY REGIONS...

   ...SUMMARY...
   Severe storms are possible Saturday across the lower Mississippi
   through Tennessee Valley regions. All hazards are possible including
   large hail, damaging wind, and tornadoes. Potential for a strong
   tornado exists from eastern Arkansas into western Tennessee. Other
   severe storms are possible across a portion of the Midwest with
   isolated damaging wind and large hail the main threats.

   ...Synopsis...
   At upper levels, a southern stream shortwave trough will move
   through the southern High Plains into central Texas. A northern
   stream shortwave trough will amplify across the upper Midwest. These
   features will eventually phase late in the period near the
   Mississippi Valley. At the surface, a warm front in the Southeast
   will advance northward before slowing/stalling in the vicinity of
   the Tennessee Valley. A surface cyclone will deepen across Illinois
   and Wisconsin and bring a cold front through the upper Midwest
   southward into the lower Mississippi Valley.

   ...Lower Mississippi through Tennessee Valleys...
   Moisture return will be ongoing at the start of the period and
   through the day. With upper 60s to low 70s F dewpoint currently
   along the Gulf Coast, it seems probable that mid to upper 60s
   dewpoints will exist in the warm sector. Given potential for
   elevated thunderstorms to develop along the northward advancing warm
   front, there is some uncertainty as to how far north the effective
   boundary will be. Even so, surface heating should support
   boundary-layer destabilization with 1500-2000 J/kg MLCAPE by the
   afternoon. Effective shear will be strong at 50-65 kts. Organized
   storms will be capable of all severe hazards. The greatest potential
   for tornadoes and larger hail will exist with storms that develop on
   the slowing warm front where more cellular development would be
   possible. Later in the evening, the cold front will move through the
   region and damaging wind gusts will become the primary threat,
   though QLCS circulations will also be possible given adequate
   low-level shear profiles.

   ...Midwest...
   Mid-level cooling along with the northern stream trough will support
   storm development along the cold front during the afternoon. Limited
   boundary-layer moisture will keep buoyancy more marginal with
   northward extent, though 1000 J/kg MLCAPE is possible. Strong
   deep-layer wind profiles and cold temperatures aloft will support
   marginally severe hail and isolated damaging wind gusts.

   ...Carolinas...
   A broad region of southerly flow will develop south of a stalled
   front within the Carolina Piedmont region. Isolated storms may
   develop along/near the boundary. Effective shear of 40-50 kts and
   relatively steep mid-level lapse rates will bring potential for
   marginally severe hail and damaging wind gusts. Wind gust potential
   will be maximized where parcels are surface based along and south of
   the boundary.

   ..Wendt.. 03/26/2021

[jaxjagman]

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
425 PM EDT Fri Mar 26 2021
 
Day 2
Valid 12Z Sat Mar 27 2021 - 12Z Sun Mar 28 2021 

...THERE IS A MODERATE RISK FOR EXCESSIVE RAINFALL ACROSS PARTS OF 
THE MID-SOUTH FROM THE LOWER MISSISSIPPI VALLEY INTO THE TENNESSEE 
VALLEY...

2030 UTC Update...
Have upgraded a portion of the Slight Risk to Moderate, based on 
the growing model consensus of where the heaviest rain is more 
likely to occur. There is still some spread -- not only with the 
CAMs (NAM Conus-Nest farther north), but also with the non-CAM 
guidance (NAM and GFS continue to be north of the EC/UKMet/CMC_reg 
consensus). The last several NBM runs in fact are also honing in 
on a max QPF axis within the upgraded Moderate Risk area. While 
not overlapping with the heaviest rainfall that fell farther 
south-southeast Thursday, the latest NASA SPoRT 0-100 cm soil 
moisture percentiles continue to be over 95% of normal within the 
Moderate Risk area, and as such there is a reflection of this in 
the reduced FFG values. 

The Moderate Risk was strategically placed across areas that can 
expect a decent slug of rainfall associated with the elevated 
convection ahead of the warm front, along with the subsequent 
linear segments expected overnight Sat-Sun where, given the uptick 
in southwesterly flow (50-60kts at 850 mb), some training is 
expected. Compared to this time yesterday, the thermodynamic 
parameters per the GEFS and SREF have increased, especially with 
more robust low-mid level moisture transport and flux anomalies. 
Some of the latest CAMs -- including the more recent 18Z HRRR -- 
show hourly rainfall rates of 1.5-2.5+ inches underneath the 
strongest cells from late Saturday afternoon through Sunday night 
ahead of the cold front. Some of the CAMs show isolated 24hr 
rainfall totals of 4-7+ inches, which would approach the 2-5 year 
ARI. 

[Chinook]

Day-1 convective outlook has 30%/30%/10% around Memphis

a part of the convective outlook (06z)

Quote

Forecast wind profiles favor supercells and lapse rates should be
   sufficiently steep for very large hail with storms across the
   western half of the ENH Risk. Tornadoes are also possible, a few
   potentially strong, with discrete storms, though QLCS-type spin ups
   are also possible as a squall line matures later in the evening. As
   the squall line matures, the threat for strong, damaging winds will
   become more likely as deep-layer westerly flow increases across the
   mid-South Region.

 

[Holston_River_Rambler]

I may just be seeing things, but it almost looks like the storm heading towards Cumberland County has a couplet:

 

[Holston_River_Rambler]

It's not showing up on the MRX scan, but that area is a weird one for radar, since it is about half way between OHX and MRX. 

[Holston_River_Rambler]

Well, I see the NWS Special weather statement now, looks like just a strong storm with Penny - Nickle sized hail. Headed for me though, so we'll see what I get here. 

[Holston_River_Rambler]

It's warned now with 1.5" hail:

The National Weather Service in Morristown has issued a

* Severe Thunderstorm Warning for...
  Central Morgan County in east Tennessee...

* Until 845 AM EDT.

* At 758 AM EDT, a severe thunderstorm was located near Fairfield
  Glade, or 11 miles northeast of Crossville, moving northeast at 50
  mph.

  HAZARD...Ping pong ball size hail.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect
           damage to roofs, siding, windows, and vehicles.

* Locations impacted include...
  Wartburg, Sunbright, High Point, Frozen Head State Park, Deerlodge
  and Rugby State Park.

[jaxjagman]

Definite ping pongs,woke me up earlier

[Runman292]

Mesoscale Discussion 0276
   NWS Storm Prediction Center Norman OK
   0741 AM CDT Sat Mar 27 2021

   Areas affected...Much of middle and eastern Tennessee into parts of
   southeastern Kentucky and southwestern Virginia

   Concerning...Severe potential...Watch possible 

   Valid 271241Z - 271445Z

   Probability of Watch Issuance...40 percent

   SUMMARY...An evolving cluster of thunderstorms will continue
   spreading across the Tennessee Valley toward the Cumberland Plateau
   through 11 AM to Noon EDT, with some potential to organize further
   and begin producing strong to perhaps occasionally severe wind
   gusts.  It is not yet certain that a severe weather watch will be
   needed, but trends will continue to be monitored for this
   possibility.

   DISCUSSION...Consolidation and upscale growth of vigorous
   thunderstorm development continues across parts of the Mid South
   into Tennessee Valley region.  This is being supported by
   large-scale ascent associated with lower/mid tropospheric warm
   advection, beneath a zone of enhanced divergence aloft, which is
   forecast to continue spreading across the Tennessee Valley into the
   Cumberland Plateau through 15-16Z.

   This convection includes at least one area of increasing
   organization, with a possible evolving broad mesoscale cyclonic
   circulation near Nashville.  This still appears rooted above at
   least a shallow near-surface, potentially cool/stable layer, but mid
   60s+ F surface dew points have been surging toward the southern
   Tennessee state border area the past few hours.  Although cloud
   cover appears likely to slow boundary-layer insolation ahead of
   activity, it is possible that thermal advection and moistening could
   contribute to increasing boundary-layer instability as far north as
   the Interstate 40 corridor of eastern Tennessee within the next few
   hours.  If this occurs, a corridor with potential for strong to
   severe wind gusts could begin to develop by mid to late morning, in
   the presence of sheared, 30-50+ kt southwesterly to
   west-southwesterly flow in the 850-500 mb layer.

[janetjanet998]

AY 1 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
0800 AM CDT SAT MAR 27 2021  
  
VALID 271300Z - 281200Z  
  
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE  
MID-SOUTH AND TENNESSEE VALLEY...  
   
..SUMMARY  
  
SEVERE STORMS ARE LIKELY ACROSS THE LOWER MISSISSIPPI THROUGH  
TENNESSEE VALLEY REGIONS TODAY INTO TONIGHT. ALL HAZARDS ARE  
POSSIBLE INCLUDING LARGE HAIL, DAMAGING WIND, AND TORNADOES,  
POTENTIALLY INCLUDING A STRONG TORNADO RISK FROM SOUTHERN/EASTERN  
ARKANSAS INTO NORTHERN MISSISSIPPI AND WESTERN TENNESSEE. OTHER  
SEVERE STORMS ARE POSSIBLE ACROSS THE MIDWEST, WITH ISOLATED  
DAMAGING WIND AND SEVERE HAIL BEING THE MAIN THREATS.  
   
..ARKLATEX/MID-SOUTH AND TENNESSEE VALLEY  
  
SUPPORTED BY ELEVATED MOISTURE TRANSPORT NEAR/NORTH OF A WARM FRONT,  
SCATTERED STRONG TO LOCALLY SEVERE THUNDERSTORMS ARE ONGOING IN THE  
PREDAWN HOURS ACROSS FAR NORTHERN MISSISSIPPI/SOUTHWEST TENNESSEE  
INTO MIDDLE/EASTERN TENNESSEE. ISOLATED SEVERE HAIL WILL BE POSSIBLE  
EARLY TODAY, ALTHOUGH CONTINUED STORM MERGERS/FURTHER UPSCALE GROWTH  
SHOULD CURB HAIL MAGNITUDES WHILE OTHERWISE POTENTIALLY YIELDING A  
FEW DAMAGING WIND GUSTS, ESPECIALLY WITH THE STORMS IN CLOSER  
PROXIMITY TO THE WARM FRONT. FOR ADDITIONAL SHORT-TERM DETAILS, SEE  
MESOSCALE DISCUSSION 276. THAT SAID, A MORE CONSEQUENTIAL SEVERE  
RISK IS ANTICIPATED ACROSS THE REGION LATER THIS AFTERNOON AND  
TONIGHT.  
  
AN UPSTREAM POSITIVELY TILTED SHORTWAVE TROUGH OVER SOUTHERN  
PORTIONS OF ARIZONA/NEW MEXICO EARLY TODAY, AS WELL AS A MORE  
SUBSTANTIAL UPPER TROUGH CROSSING THE DAKOTAS/UPPER MIDWEST, WILL  
INFLUENCE HEIGHT FALLS/CYCLOGENESIS OVER THE REGION BUT NOT UNTIL  
LATER TONIGHT. REGARDLESS, A SEMI-PERSISTENT WARM/MOIST CONVEYOR MAY  
CONTINUE TO YIELD SHOWERS/THUNDERSTORMS IN VICINITY OF THE WARM  
FRONT, WITH THIS RAIN-COOLED AIR/OUTFLOW LIKELY BEING A SIGNIFICANT  
FACTOR (AND POINT OF UNCERTAINTY) ACROSS EAST/NORTHEAST ARKANSAS AND  
WESTERN/MIDDLE TENNESSEE (AND AREAS TO THE NORTH) REGARDING THE  
NORTHERN EXTENT OF THE LATER-DAY PEAK SEVERE RISK.  
  
TO THE SOUTH/SOUTHWEST OF THESE EARLY DAY STORMS, IN CONJUNCTION  
WITH MIDDLE/UPPER 60S F SURFACE DEWPOINTS, THE STRONGEST LOW-LEVEL  
HEATING/DESTABILIZATION IS EXPECTED ACROSS NORTHEAST TEXAS/ARKLATEX  
AND SOUTHERN/EASTERN ARKANSAS INTO NORTHERN MISSISSIPPI AND  
SOUTHWEST TENNESSEE, WHERE MLCAPE SHOULD REACH 2000-2500 J/KG.  
INITIAL DEVELOPMENT/MATURATION OF SURFACE-BASED STORMS SHOULD OCCUR  
BY AROUND 3-6 PM CDT WITHIN THIS CORRIDOR.   
  
FORECAST WIND PROFILES FAVOR SUPERCELLS AND LAPSE RATES SHOULD BE  
SUFFICIENTLY STEEP FOR ISOLATED VERY LARGE HAIL WITH THESE STORMS.  
AS LOW-LEVEL SHEAR/SRH CONSIDERABLY STRENGTHENS, A COUPLE OF STRONG  
TORNADOES (EF2+) WILL BE POSSIBLE, PARTICULARLY LATE THIS AFTERNOON  
INTO EVENING, ACROSS SOUTHERN/EASTERN ARKANSAS INTO NORTHERN  
MISSISSIPPI AND WESTERN TENNESSEE. HOWEVER, THE ANTICIPATED  
EVOLUTION OF A SOMEWHAT MIXED CONVECTIVE MODE, COINCIDENT WITH THE  
TIMING OF ENLARGING LOW-LEVEL HODOGRAPHS TOWARD/AFTER SUNSET, LEADS  
TO SOME UNCERTAINTIES REGARDING HIGHER-END TORNADO POTENTIAL.  
  
AN UPSCALE-GROWING QUASI-LINEAR CONVECTIVE SYSTEM WILL LIKELY  
ORGANIZE AND ACCELERATE EASTWARD THIS EVENING INTO THE OVERNIGHT,  
WITH DAMAGING WINDS BECOMING AN INCREASING CONCERN ASIDE FROM A  
QLCS-RELATED TORNADO RISK AS STORMS SPREAD ACROSS SOUTHEAST  
ARKANSAS, NORTHERN PORTIONS OF MISSISSIPPI/ALABAMA, AND MUCH OF  
TENNESSEE.   

[1234snow]

I’m really surprised the SPC didn’t issue a Severe Thunderstorm watch for the forum area. There have been plenty of warnings issued this morning and 8 hail reports in the database at SPC.

I feel like Flash Flooding will become a big issue statewide as well. 12z NAM really upped totals close to 6 inches for a wide part of the mid-state. 12z HRRR showed similar totals.

[1234snow]

Rogersville is fixing to hit up with a cell that RadarScope indicates up to 1.25” hail. No warning on that currently.

[1234snow]

Flash flood warning already issued for 5 TN counties just north of the MS border. Long way to go in the event. Not a great sign to see flash flood warnings already.

[jaxjagman]

been seeing some weak rotation towards the SW

[nrgjeff]

Storm chase target: Corinth, Miss to the Shoals, Bama with options to hold Huntsville or push Memphis. Outflow favored over rainy warm front Tenn. Question is whether that climo favored convergence zone develops MS/AL border like with more organized systems.

This really reminds me more of late season Plains outflow, with a subtle short-wave upstairs and fluctuating LLJ. Less hype ENH, oh yeah! Hodos are excellent low and long high. That's splits, like the 5am special Chattanooga. Right movers make easy chase decisions. 

Delta is sweet flat clear terrain; however, my luck there is about like KU vs USC. Memphis chase partners want me to go there. Will try Miss/Bama first per Dixie climo. Last post of the day. Everyone stay safe!

[1234snow]

78dbz on RadarScope with hail marker at 4” with cell SW of Johnson City and Jonesborough. Hail core of 2” passing over downtown Kingsport currently.

[janetjanet998]

  
MESOSCALE PRECIPITATION DISCUSSION 0074  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1122 AM EDT SAT MAR 27 2021  
  
AREAS AFFECTED...TN  
  
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE  
  
VALID 271521Z - 272100Z  
  
SUMMARY...AN ISOLATED TO SCATTERED FLASH FLOOD RISK WILL PERSIST  
ACROSS PORTIONS OF SOUTHWEST AND SOUTH CENTRAL TN.  
  
DISCUSSION...HEAVY CONVECTION EARLIER THIS MORNING HAS FORWARD  
PROPAGATED EASTWARD ACROSS THE STATE OF TN. CONVECTIVE EVOLUTION  
OVER THE NEXT SEVERAL HOURS IS A BIT MORE UNCERTAIN. THE MOST  
FAVORED AXIS FOR HEAVY RAINFALL INTO THE EARLY AFTERNOON HOURS IS  
LIKELY ON THE SOUTH AND SOUTHWEST FLANK OF THE ONGOING CONVECTIVE  
COMPLEX. IT IS HERE...WHERE THE STRONG LOW LEVEL SOUTHERLY FLOW IS  
IMPINGING ON THE CONVECTIVE COMPLEX...WHERE CONVERGENCE IS  
MAXIMIZED. HAVE COMPETING FACTORS IN PLAY OVER THE NEXT SEVERAL  
HOURS...ON ONE HAND INSTABILITY WILL CONTINUE TO INCREASE UPSTREAM  
OF THE CONVECTION, PWS WILL REMAIN STEADY OR GRADUALLY INCREASE,  
AND A LOW LEVEL CONVERGENCE AXIS WILL PERSIST. ON THE OTHER HAND  
WE ARE GENERALLY IN BETWEEN FORCING MECHANISMS, AND A SLIGHT  
DECREASE IN LOW LEVEL MOISTURE TRANSPORT SHOULD RESULT IN SOME  
WEAKENING/BROADENING OF THE LOW LEVEL CONVERGENCE AXIS. THUS IT IS  
A TOUGH CALL ON HOW INTENSE/ORGANIZED CONVECTION IS INTO THE EARLY  
AFTERNOON HOURS.  
  
WHAT WE ARE MORE CONFIDENT IN IS THE APPROXIMATE CORRIDOR OF  
FAVORED CONVECTIVE TRAINING/BACKBUILDING OVER THE NEXT SEVERAL  
HOURS. THAT IS ON THE SOUTHWEST FLANK OF ONGOING ACTIVITY...MAINLY  
ACROSS SOUTHWEST AND SOUTH CENTRAL TN. THE MITIGATING FACTORS  
DESCRIBED ABOVE MAY KEEP THE ACTIVITY A BIT MORE  
DISORGANIZED/TRANSIENT INTO THE EARLY AFTERNOON. BUT THE  
INCREASING INSTABILITY AND CONTINUED PRESENCE OF THE CONVERGENCE  
AXIS, SUGGESTS AT LEAST AN ISOLATED TO SCATTERED FLASH FLOOD RISK  
WILL PERSIST INTO THE EARLY AFTERNOON.  
  
BY MID TO LATE AFTERNOON WE SHOULD BEGIN TO SEE AN UPTICK IN  
MID/UPPER FORCING FROM THE WEST, ALONG WITH A RENEWED INCREASE IN  
LOW LEVEL MOISTURE TRANSPORT, HELPING RE-INTENSIFY THE CONVERGENCE  
AXIS. THUS THE FLASH FLOOD RISK WILL LIKELY BEGIN RAMPING UP BY  
MID/LATE AFTERNOON INTO THE EVENING HOURS. THIS UPTICK BY MID/LATE  
AFTERNOON INTO THE EVENING IS OF HIGH CONFIDENCE. IT IS JUST LATE  
MORNING INTO EARLY AFTERNOON WHERE THE RISK MAY TEMPORARILY BECOME  
MORE ISOLATED/SCATTERED...BUT AS MENTIONED ABOVE...EVEN DURING  
THIS PERIOD SOME FLASH FLOOD RISK IS STILL EXPECTED TO PERSIST.  
  
CHENARD  

[Icy Hot]

Just had 2 cells move thru Kingsport. One 2 miles to the North brought a deluge, multiple lightning strikes and pea-sized hail.

[Holston_River_Rambler]

Nice cloud pic posted by a tavern in downtown Carthage:

https://www.facebook.com/ebelstavern/photos/a.450163365365397/1352014735180251/

 

 

[McMinnWx]

The video below shows hail in Johnson City. 
 

https://twitter.com/andyvjeffers/status/1375834920032071684?s=21

[jaxjagman]

xcessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1157 AM EDT Sat Mar 27 2021
 
Day 1
Valid 16Z Sat Mar 27 2021 - 12Z Sun Mar 28 2021 

...THERE IS A MODERATE RISK FOR EXCESSIVE RAINFALL ACROSS PARTS OF 
THE MID-SOUTH AND TENNESSEE VALLEY...

16z Update: No major changes needed to the ERO at this time. 12z 
HREF members and recent HRRR runs still support a Moderate risk 
from eastern AR, into northern MS/AL and much of TN. Portions of 
this area have already seen 1-3" of rain earlier today...and going 
into the event soil saturation values were already well above 
average. Thus antecedent conditions remain favorable for 
additional flash flooding. Currently we are generally in between 
forcing mechanisms, and a slight decrease in low level moisture 
transport should result in some weakening/broadening of the low 
level convergence axis. However, by mid to late afternoon we 
should begin to see an uptick in mid/upper forcing from the west, 
along with a renewed increase in low level moisture transport, 
helping re-intensify the convergence axis. Thus the flash flood 
risk will likely begin ramping up by mid/late afternoon into the 
evening hours. This uptick by mid/late afternoon into the evening 
is of high confidence. It is just late morning into early 
afternoon where the risk may temporarily become more 
isolated/scattered...but even during this period some flash flood 
risk is still expected to persist.

The multiple convective rounds, combined with favorable antecedent 
conditions, supports a scattered to widespread flash flood event 
as we head through the evening hours. Embedded within this 
Moderate risk there may very well be a narrower axis that receives 
6-9" of rainfall. If this does occur then a focused corridor of 
more significant and dangerous flash flooding is possible...with 
the greatest chance of this from far northern MS/AL into 
southwest/south central TN. Given amounts of this magnitude and 
already saturated conditions, High risk level impacts are 
certainly a possibility over a narrow axis. However, no upgrade 
with this update, as the localized nature and uncertainty supports 
maintaining a broader Moderate risk at this time.

Chenard

[janetjanet998]

 

 

DAY 1 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
1124 AM CDT SAT MAR 27 2021  
  
VALID 271630Z - 281200Z  
  
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON  
INTO TONIGHT FROM PARTS OF THE ARK-LA-TEX ACROSS THE MID SOUTH AND  
TN VALLEY...  
   
..SUMMARY  
  
SEVERE STORMS ARE LIKELY THIS AFTERNOON INTO TONIGHT FROM THE  
ARK-LA-TEX EAST-NORTHEASTWARD ACROSS PARTS OF THE MID SOUTH AND  
TENNESSEE VALLEY. ALL HAZARDS ARE POSSIBLE INCLUDING VERY LARGE  
HAIL, SIGNIFICANT DAMAGING WINDS, AND A COUPLE OF STRONG TORNADOES.  
   
..MID SOUTH/TN VALLEY REGION THROUGH TONIGHT  
  
ELEVATED CONVECTION WITH A MARGINAL HAIL THREAT THAT FORMED  
OVERNIGHT IN A ZONE OF WARM ADVECTION, ALONG AND NORTH OF THE  
SURFACE WARM FRONT FROM THE MID SOUTH INTO MIDDLE/EASTERN TN,  
PERSISTS AS OF LATE MORNING.  THE CONVECTION IS ALSO ASSOCIATED WITH  
A SUBTLE MID-UPPER SPEED MAX MOVING EAST-NORTHEASTWARD OVER THE MID  
SOUTH.  FARTHER WEST, ADDITIONAL STORM DEVELOPMENT IS EXPECTED BY  
EARLY-MID AFTERNOON ALONG THE RAIN-REINFORCED FRONT CLOSE TO THE  
MS/AL/TN BORDER REGION.  THIS AFTERNOON CONVECTION WILL LIKELY BE  
ROOTED AT THE SURFACE AS THE LOW LEVELS CONTINUE TO WARM/MOISTEN  
FROM THE SOUTH, WITH A FEW SUPERCELLS POSSIBLE WITH MLCAPE NEAR 2000  
J/KG, EFFECTIVE BULK SHEAR NEAR 50 KT, AND EFFECTIVE SRH AROUND 150  
M2/S2.  
  
FARTHER WEST INTO NORTHEAST TX AND SOUTHERN/EASTERN AR,  
SURFACE-BASED SUPERCELL DEVELOPMENT IS EXPECTED BY MID AFTERNOON  
ALONG THE MOISTURE GRADIENT/WARM FRONT, AS THE LOW LEVELS CONTINUE  
TO DESTABILIZE AND THE CAP WEAKENS.  THE FORCING FOR ASCENT WILL BE  
RATHER SUBTLE, SO THE PRIMARY STORM MODE SHOULD BE A MIX OF DISCRETE  
SUPERCELLS AND CLUSTERS MOVING EAST-NORTHEASTWARD ALONG THE BUOYANCY  
GRADIENT/FRONT THIS AFTERNOON INTO EARLY TONIGHT.  ISOLATED VERY  
LARGE HAIL, DAMAGING WINDS, AND A COUPLE OF TORNADOES WILL BE THE  
MAIN CONCERNS THIS AFTERNOON.  SOME INCREASE IN LOW-LEVEL SHEAR IS  
EXPECTED THIS EVENING, WHICH WILL SUPPORT AN INCREASE IN THE TORNADO  
THREAT, WITH AN ISOLATED STRONG TORNADO OR TWO POSSIBLE.  OTHERWISE,  
STORMS OVERNIGHT SHOULD CONSOLIDATE INTO MORE OF A SOLID BAND AS THE  
SYNOPTIC COLD FRONT OVERTAKES THE CONVECTION FROM THE NORTHWEST, IN  
RESPONSE TO PHASING OF THE NORTHERN AND SOUTHERN STREAMS, WITH  
CYCLOGENESIS FROM IL TO LOWER MI.  
   
..EASTERN OK/NORTHWESTERN AR TO IL THIS AFTERNOON/EVENING  
  
THE PRIMARY SURFACE CYCLONE IS EXPECTED TO BEGIN DEEPENING THIS  
EVENING ACROSS IL, BEFORE MOVING TO LOWER MI OVERNIGHT.  IN THE WAKE  
OF THE LOW, A COLD FRONT WILL BEGIN TO ACCELERATE SOUTHEASTWARD  
LATER THIS EVENING INTO TONIGHT.  THE PRIMARY UNCERTAINTIES ALONG  
THIS CORRIDOR ARE THE DEGREE OF LOW-LEVEL  
MOISTENING/DESTABILIZATION, AND THE MAGNITUDE OF THE LOW-LEVEL  
SHEAR.  THE MAIN LOW-LEVEL MASS RESPONSE/LOW-LEVEL JET WILL LIKELY  
BE DIRECTED INTO THE RATHER PERSISTENT ZONE OF CONVECTION FARTHER TO  
THE SOUTHEAST ALONG THE EFFECTIVE WARM FRONT FROM NORTHEAST TX TO  
WESTERN TN.  THESE FACTORS SUGGEST SUBSTANTIAL LIMITATIONS TO THE  
WIND/HAIL THREAT ALONG THE COLD FRONT FARTHER TO THE NORTHWEST, WITH  
THE MOST QUESTIONABLE AREA CENTERED ON NORTHWESTERN AR.  
   
..CAROLINAS THIS AFTERNOON/EVENING  
  
THE CLUSTER OF STORMS IN EASTERN TN HAS BEEN ELEVATED THROUGH THE  
MORNING, BUT SOME NORTHWARD EXPANSION OF THE SURFACE WARM SECTOR IS  
EXPECTED THROUGH THIS AFTERNOON FROM SC INTO NC.  GIVEN SUFFICIENT  
DEEP-LAYER VERTICAL SHEAR, AN ORGANIZED CLUSTER WITH SOME THREAT FOR  
DAMAGING WINDS/LARGE HAIL MAY PERSIST INTO THE AFTERNOON ALONG THE  
WARM FRONT FROM THE PIEDMONT EASTWARD ACROSS NC AND ADJACENT  
PORTIONS OF SC.  
  

[Math/Met]

Greeneville hail from earlier today. Taken about 30 minutes after the storm.

[PowellVolz]

Got this shelf moving ENE. I’m at Ruggles Ferry GC looking NW




.

[PowellVolz]

 

Pic won’t show up for some reason

 

.

[Dsty2001]

1 minute ago, Math/Met said:

Greeneville hail from earlier today.

Yeah it woke me up,was crazy 

[jaxjagman]

Just now, PowellVolz said:

Got this shelf moving ENE. I’m at Ruggles Ferry GC looking NW




.

Oh nice !!

[PowellVolz]

Oh nice !!

Oh so you can see it?


.

[jaxjagman]

Yeah,the link works

[Math/Met]

1 minute ago, PowellVolz said:

Oh so you can see it?


.

I can see it. Great picture.