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Tn Valley Severe Weather


jaxjagman
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On 1/21/2022 at 9:32 AM, nrgjeff said:

CFS and GFS weeklies are both trending toward the ECMWF weeklies, in that the second week of February may return to warmer than normal. Depending on the amount of toughing in the West and Plains -PNA? it will be time to think about early season severe weather and storm chasing. Waiting for the Plains has not been rewarding recent years. Chase everything in Dixie!

Barring a sharply colder forecast change over the weekend, I'm about done in the winter threads. Chatty doesn't have a snowball in hell prayer early next week. Look for me in this thread. La Nina! Tee up early and often Southern severe!!

Some of the anoms are acting like 2011 just a few weeks ahead ,.If the CFS is right It shows the MJO start to strenghten into the IO/Maritime and possibly a stronger signal into the WP.Either way, possibly a time to keep a eye out into the start of Met spring right now

PowerPoint Presentation.png

Tropical Monitoring __ North Carolina Institute for Climate Studies (5).png

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  • 2 weeks later...

Seems maybe some cross breed from 2012 Nina to 2018 Nina.You can go beyond those times into the 1950's to the 1980 but GW is real.NINA looks like 1996,2001.2012,2018 and even 2021.

2012 was the off year with severe out of those years.But it produced some strong tornadoes east of 1-65 in spring and even the deadly Derecho in Chatty that year.

 

Either way,the big record breaking -PNA in Dec since records were taking since 1950 with the help of the Aluetian High was set at -2.76 it was a big factor with our historic severe Fall season into Met winter

 

 

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.pna.monthly.b5001.current.ascii.table

rmm_total.40.png (628×653) (1).png

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8 minutes ago, nrgjeff said:

Both! What else would one expect in the South? LOL

Dear ECMWF tee up some North Alabama Day 10.5

Spring is almost here for sure, or at least spring followed by a little more cold during early March...then it could get wild.  It is teed-up for you severe folks.  Just keep the hail from shredding my roof and cars.  $30K is enough for one decade!

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Perhaps the thunder followed by snow can verify in the mountains. Just saw another Southeast Tennessee system turn offshore snoozer. I've closed the books on winter Southeast Tenn.

GFS picks up on the severe system Day 10 but there are typical questions 10 days out. Watch it slide south and snow on Chatty just to make me eat my words, haha!

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Weekly products all support severe weather on or after President's Day. AN temps with AN precip Mid South or Deep South. Hints of a passing wave that week before a more robust SER. Then start Hoosier Alley season!

Other evidence is a severe favorable MJO impulse. Also the Polar Vortex is locked up so no SSW to spoil early chase season.

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Just now, jaxjagman said:

I still believe the best analog year is NINA of 2011-2012 for us in the Valley,plus it matches up well with the ENSO.Only takes one big outbreak to not make your day .

rmm_variable.40.png (971×1056).png

Had Cen AL not "benefitted" from flooding rains 17 & 25 March and then May 2021 we would've probably have had a much more serious severe weather outbreak than we actually had. Both March days did get bad with damaging tornadoes but convection worked over the area to the point that we stopped short of what most would consider "High Risk" events.

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If it can happen in the Plains in early March, Hesston KS Mar. 13, 1990 it certainly happens in the South. That day in March 2012 was prolific on a national scale. 

This (Saturday) morning SPC expanded the Thursday 15% east to the Alabama Georgia line. Gets into the Lower Plateau as well. 

As for the MJO, we got a buffet line of convection going into the Maritime Continent. -PNA is indeed activated. 

image.thumb.png.991aa6cdd740455b4d9fc4f1a37821d6.png

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Mississippi I have more confidence in on Thursday. Surface temps should hit 70 degrees with 65 dews. Prefrontal trough will slam into that environment.

Alabama will depend on how the warm front behaves. Midday rain would keep it stable. Morning rain lifting into Tennessee would open Alabama to outflow. Little if any rain would leave the warm front, but still surface heating questions. No rain would leave a stratus deck in tact. Stratus is pattern recognition early season warm 850 Ts.

Bottom Line: Alabama has two paths to keeping stable and only one path to severe. Mississippi is probably reverse, a 2/3 chance of severe. 

 

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Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1128 AM CST Wed Feb 16 2022

   Valid 171200Z - 181200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE
   MISSISSIPPI DELTA REGION EASTWARD ACROSS THE TENNESSEE VALLEY...

   ...SUMMARY...
   Severe thunderstorms are expected across portions of the Lower
   Mississippi Valley, Mid-South, and Southeast on Thursday.

   ...Synopsis...
   Phasing of a northern-stream upper trough crossing central Canada
   and the north-central U.S. with a southern-stream trough crossing
   the southern Rockies/southern Plains will occur Thursday, with
   eastward progression of the consolidating feature expected.  This
   system will be characterized by very strong deep-layer flow on its
   southeast flank, across the south central into the eastern CONUS.

   At the surface, a deepening low is progged to be shifting eastward
   out of Oklahoma across the northern Arkansas/far southern Missouri
   region through the day, and then northeastward along the Ohio Valley
   into the evening hours.  A broad, moistening warm sector will exist
   across the Mid South and Southeast, until a cold front, advancing
   eastward with time, ushers in colder/drier air.  This front is
   expected to reach the Mississippi Delta region during the afternoon,
   the Appalachian crest overnight, and then extend from the
   Mid-Atlantic region to the Florida Panhandle by 18/12Z.

   ...Arklatex region eastward across the Mid South and central Gulf
   Coast region...
   Widespread showers and embedded thunderstorms will be ongoing at the
   start of the period from southeastern Kansas southward to eastern
   Oklahoma and Arkansas and into northeastern Texas at the start of
   the period, near and ahead of the advancing surface low/cold front. 
   Meanwhile, largely elevated, warm advection-induced convection will
   extend northeastward across the Mid Mississippi and Ohio Valleys and
   vicinity.  While meager CAPE is expected early in the period, strong
   flow aloft suggests that locally damaging wind gusts will be a
   possibility from the Arklatex region eastward toward the Mississippi
   Delta area through mid afternoon.

   With time, deepening of the low and associated strengthening of
   low-level southerlies will allow persistent northward theta-e
   advection to combine with modest/local diurnal warming, eventually
   yielding evolution of mixed-layer CAPE up to about 500 J/kg.  Across
   Kentucky and areas north, a cool boundary layer should persist,
   resulting in slightly stable conditions beneath evolving, modest
   instability.  However, this thermodynamic concern is partially
   offset by stronger ascent aloft spreading across this region --
   along with the deepening low expected to track along roughly the
   Ohio River through late afternoon and into the evening.  With this
   ascent likely to maintain partially forced convection, and given
   exceptionally strong/veering flow with height across this region,
   potential for locally damaging winds and a couple of tornadoes
   remains a possibility.

   Farther south, greater low-level theta-e advection suggests that the
   boundary layer will become at least neutral, and therefore greater
   certainty of surface- or near-surface-based storms exists -- both
   near the advancing cold front, and also with associated warm
   advection-driven bands of convection in the free warm sector.  As
   noted above, very strong shear -- with south-southwesterly 850 mb
   winds in excess of 50 to 60 kt increasing to west-southwesterly at
   70 to 90 kt at mid levels -- is suggestive of supercells, and
   attendant risk for damaging winds and several -- and possibly
   locally strong/damaging -- tornadoes.  As such, an upgrade to
   enhanced risk is being introduced, centered across the Tennessee
   Valley area from late afternoon through the evening hours.

   ..Goss.. 02/16/2022
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e70f134bd79abaf831cc6b9215d741dc.gif

“As noted above, very strong shear -- with south-southwesterly 850 mb winds in excess of 50 to 60 kt increasing to west-southwesterly at 70 to 90 kt at mid levels -- is suggestive of supercells, and attendant risk for damaging winds and several -- and possibly locally strong/damaging -- tornadoes. As such, an upgrade to enhanced risk is being introduced, centered across the Tennessee Valley area from late afternoon through the evening hours”


.

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  • 2 weeks later...

Yeah the signal could be there. Also seeing a possible colder 16-20 Day. One has to expect a significant system in the transition. 

Possible MJO move could support the severe wx pattern; however, it's quite muddled right now. Including tropical cyclones which are wild cards - though not as much so from the Southern Hemisphere.

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Friday free for all. Time to start jawboning Sunday and Monday.

Sunday Slight gets into Western Tenn. Flat Arkansas Delta might be the most interesting chaser aspect. Heights are rising though. LLJ ramps up anyway. It's almost like a later spring setup. 

Monday the Day 4 covers the Region from I-40 south. Inverse of my usual snow commentary, ha. Main system is lifting away, but CAPE and wind shear remain in our warm sector. 

Lots of college basketball will probably keep me home Sunday. Work would be the problem Monday. Unless it mainly keeps south of Tenn.

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MJO looks like it could possibly strenghten into the IO/Maritime the next several days.Euro shows a upper level ridge into East Asia around this time next weekend followed by a trough into East Asia.Possibly a time frame to watch i believe around the 3rd week of March.

 

20220306_00z-fcst_valid-2022-03-19-png-660×419-.png

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