Jan 18, 2019 1630 UTC Day 1 Convective Outlook
Updated: Fri Jan 18 16:24:02 UTC 2019 (20190118 1630Z Day 1 shapefile | 20190118 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20190118 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 147,185 8,841,887 Memphis, TN...Shreveport, LA...Little Rock, AR...Jackson, MS...Tyler, TX...
Probabilistic Tornado Graphic
20190118 1630 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
2 % 86,184 4,376,436 Shreveport, LA...Jackson, MS...Longview, TX...Bossier City, LA...Pine Bluff, AR...
Probabilistic Damaging Wind Graphic
20190118 1630 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 105,976 6,755,638 Memphis, TN...Shreveport, LA...Little Rock, AR...Jackson, MS...Tyler, TX...
Probabilistic Large Hail Graphic
20190118 1630 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 119,951 7,111,090 Memphis, TN...Shreveport, LA...Little Rock, AR...Tyler, TX...Broken Arrow, OK...
   SPC AC 181624

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1024 AM CST Fri Jan 18 2019

   Valid 181630Z - 191200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT FROM
   EAST TX/OK TO THE ARK-LA-MISS...

   ...SUMMARY...
   Isolated strong to severe thunderstorms capable of producing hail
   may occur from parts of east Texas and Oklahoma to the ArkLaTex
   region tonight. Strong to locally damaging winds and perhaps a
   tornado could occur overnight from east Texas to the Ark-La-Miss.

   ...East TX/OK to the Ark-La-Miss tonight...
   A midlevel shortwave trough near the Four Corners will progress
   east-southeastward and amplify over the southern Plains by tonight. 
   An associated lee cyclone will develop southeastward from
   southeastern CO to southern/central OK by this evening, and then
   eastward to the Mid South by Saturday morning.  Boundary-layer
   dewpoints in the 60s across the northwestern Gulf of Mexico will
   spread inland today and tonight across east TX and the lower MS
   Valley.  Low clouds with the moisture return will limit surface
   heating/destabilization, though at least weak near-surface-based
   buoyancy is expected by tonight with the moistening and midlevel
   lapse rates near 7.5 C/km.

   Deep-layer and low-level vertical shear will increase in the warm
   sector with the approach of the midlevel trough and become favorable
   for organized severe storms, including supercells.  However, the
   potential for surface-based storms will depend heavily on small
   changes in low-level moisture tonight.  Ascent will be focused in
   warm conveyor along the northeast edge of the warm sector tonight,
   where convection will likely move northeastward faster than the low
   levels destabilize.  Other convection could form late tonight in a
   band along the cold front from east TX into northern LA and southern
   AR.  Isolated damaging gusts, and perhaps a tornado or two, will be
   possible with the frontal convection.  Will maintain a MRGL risk,
   though there will still be some potential for a SLGT risk upgrade by
   this evening, if low-level moistening is observed to be on the high
   side of the forecast envelope.

   Farther north, a few elevated thunderstorms are expected in the zone
   of ascent immediately preceding the surface cyclone from OK into AR.
   Buoyancy will likely remain elevated near I-40, which suggests that
   isolated large hail will be the main concern in a steep lapse rate
   environment.

   ..Thompson/Bentley.. 01/18/2019

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z