Ok, there is a lot to absorb here y’all. Just know the next 24-72 hours if you live in the South, you need to be weather aware. Here’s a brief synopsis before we get into the guts of Winter Storm Isaiah:

  • 3″-6″ Ice and Snow tonight from OKC through KC.
  • Severe Storms ramp up in Oklahoma and Texas by late morning. These will form a squall line that will cause issues in the Ark-La-Tex area by late afternoon into evening.
  • By late night Louisiana, Arkansas, West Tennessee, and West Mississippi are under the gun.
  • Tomorrow Tennessee,Alabama, Mississippi, Georgia and the Florida Panhandle and Carolinas are on alert.
  • Tornadoes, Straight line winds, large hail, and flash flooding and river flooding are likely with this storm system.
  • will update this tomorrow morning early for Saturday and Sunday. There is so much going on today we are just going to concentrate on this.
  • This is a good time to charge portable cell batteries, check your weather radio battery, or buy one if you don;’t have one.

Now this is the latest from NOAA Storm Prediction Center and NWS:

Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 52,958 3,807,360 Garland, TX…Shreveport, LA…Mesquite, TX…Tyler, TX…Longview, TX…
ENHANCED 102,249 18,150,854 Houston, TX…Dallas, TX…Austin, TX…Fort Worth, TX…Tulsa, OK…
SLIGHT 137,640 8,991,892 San Antonio, TX…Memphis, TN…Oklahoma City, OK…Springfield, MO…Lafayette, LA…
MARGINAL 125,830 9,879,922 Wichita, KS…St. Louis, MO…Corpus Christi, TX…Baton Rouge, LA…Jackson, MS…



   Severe thunderstorms are expected across the southern Plains into
   the lower Mississippi Valley. Damaging winds are the greatest severe
   risk, though tornadoes are possible along with very large hail
   across the southern Plains.

   ...Southern Plains/Lower Mississippi Valley...

   Late-evening water-vapor imagery depicts a well-defined short-wave
   trough over AZ/northern Mexico, shifting east in line with latest
   model guidance. This feature is forecast to advance into the
   southern Rockies by 18z as 90+kt 500mb speed max rotates into the
   base of the trough south of the Big Bend region. In response to this
   trough, LLJ is forecast to increase across northwest TX which will
   enhance low-level warm advection across western OK. Low-level
   moisture is advancing northwest across OK and should aid buoyancy
   for elevated convection between 12-14z. Forecast soundings suggest
   elevated supercells are possible early in the period and this is
   supported by CAMs with a cluster of convection that will spread
   northeast across northern OK/southern KS. As this activity spreads
   east into upper 50s/lower 60s dew points, convection will have an
   opportunity to become surface based, though discrete cells may not
   be particularly common as a polar front sags into this region.

   Farther south, strong boundary-layer heating is expected across west
   TX where surface-3km lapse rates are forecast to approach 9 C/km. At
   the same time, strong mid-level height falls will spread across the
   southern Plains by peak heating, and thunderstorms should easily
   develop along the eastern edge of this steeper lapse-rate plume.
   Latest thinking is scattered supercells will evolve from
   east-central OK - north-central TX - southwestern TX between 19-21z.
   This activity will be strongly sheared and could produce very large
   hail early in the convective cycle. With time, multi-scale forcing
   will encourage an extensive squall line that should race east toward
   the Arklatex region. Damaging winds will likely be common along this
   squall line as it advances across eastern OK/east TX during the
   evening hours. Linear MCS will continue east during the overnight
   hours, advancing to near the MS River toward the end of the period.

   While damaging winds should be the primary threat with the squall
   line, very strong shear and moist profiles will likely result in
   embedded supercells. A few tornadoes are expected along the QLCS but
   the lack of confidence in discrete pre-frontal supercells will
   preclude more than 10% tornado probs during the day1 period.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
302 AM EST Fri Jan 10 2020

Valid 12Z Fri Jan 10 2020 - 12Z Sun Jan 12 2020

...There is a moderate risk of excessive rainfall over parts of Southern
Plains, Middle Mississippi Valley, and Lower Mississippi Valley a long
with Moderate risk of severe thunderstorms over parts of the Southern
Plains/Lower Mississippi Valley...

...Heavy snow and rain/freezing rain for parts of the Great Lakes and
Upper/Middle Mississippi Valley...

...Temperatures will be 10 to 25 degrees above average over the Southern
Plains/Lower Mississippi Valley into the Ohio Valley/Great Lakes...

...Heavy snow once again possible in higher elevations of the Northwest...

A deep trough over the Rockies will move eastward to the Lower Great Lakes
by Sunday.  Along the associated front heavy rain will develop from parts
of the Southern Plains northeastward to the Great Lakes producing 1 to 3
inches.  Due to the slow progression of this system, storm motion will be
slow and expected to track over the sames area.  This will become become
problematic as soils become saturated.  A moderate risk of excessive
rainfall is forecast over parts of Eastern Oklahoma and neighboring
states.  The rain will produce numerous flash flooding will occur with
many streams being flooded and floods affecting larger rivers.  
Additionally, the Storm Prediction Center has forecast a Moderate Risk of
severe weather for parts of the Southern Plains to Lower Mississippi

On the backside of this system, light to moderate snow over the
Intermountain West and Rockies will spread eastward. A wintry mix of snow,
sleet, and rain/freezing rain is possible in portions of the
Southern/Central Plains into the Middle Mississippi Valley and
northeastward into the Great Lakes Friday into Sunday after the cold front
drops the temperatures. The heaviest rain/freezing rain is forecast over
parts of Great Lakes Saturday into Sunday.

A stark temperature gradient will setup over the country thanks to the
strong front over the Central U.S. into the Great Lakes.  In the warm
sector ahead of the front, daily temperatures will average 10 to 25
degrees warmer than typical early January readings. Numerous records are
expected to be broken from the Ohio and Tennessee Valleys into the
Northeast.  In contrast, the western half of the country will be much
colder than usual as a cold front and secondary cold front reinforces the
frigid airmass.  On Friday, high temperatures in the single digits are
forecast for the north-central tier of the nation.