May 18, 2019 2000 UTC Day 1 Convective Outlook
Updated: Sat May 18 19:59:05 UTC 2019 (20190518 2000Z Day 1 shapefile | 20190518 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20190518 2000 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 110,304 8,280,981 Dallas, TX...Plano, TX...Garland, TX...Shreveport, LA...Little Rock, AR...
SLIGHT 189,437 20,377,429 Houston, TX...Austin, TX...Memphis, TN...Oklahoma City, OK...Kansas City, MO...
MARGINAL 287,703 33,989,059 Chicago, IL...San Antonio, TX...Milwaukee, WI...Omaha, NE...Arlington, TX...
Probabilistic Tornado Graphic
20190518 2000 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
SIG SEVERE 58,581 4,025,305 Shreveport, LA...Little Rock, AR...Mesquite, TX...Waco, TX...Tyler, TX...
10 % 63,155 4,728,740 Garland, TX...Shreveport, LA...Little Rock, AR...Mesquite, TX...Waco, TX...
5 % 60,848 6,520,968 Dallas, TX...Austin, TX...Plano, TX...Irving, TX...Grand Prairie, TX...
2 % 190,776 22,046,699 Houston, TX...San Antonio, TX...Memphis, TN...Kansas City, MO...Tulsa, OK...
Probabilistic Damaging Wind Graphic
20190518 2000 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
45 % 30,203 1,883,192 Shreveport, LA...Little Rock, AR...Longview, TX...Bossier City, LA...North Little Rock, AR...
30 % 63,185 6,194,992 Dallas, TX...Plano, TX...Garland, TX...Mesquite, TX...Carrollton, TX...
15 % 205,683 20,391,108 Houston, TX...Austin, TX...Memphis, TN...Oklahoma City, OK...Kansas City, MO...
5 % 278,227 34,243,383 Chicago, IL...San Antonio, TX...Milwaukee, WI...Omaha, NE...Arlington, TX...
Probabilistic Large Hail Graphic
20190518 2000 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
SIG SEVERE 14,382 119,608 Dodge City, KS...Woodward, OK...
30 % 16,094 135,328 Dodge City, KS...Woodward, OK...
15 % 284,589 28,629,772 Houston, TX...Dallas, TX...Austin, TX...Memphis, TN...Oklahoma City, OK...
5 % 287,795 34,055,675 Chicago, IL...San Antonio, TX...Milwaukee, WI...Omaha, NE...Arlington, TX...
   SPC AC 181959

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0259 PM CDT Sat May 18 2019

   Valid 182000Z - 191200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE
   ARKANSAS VICINITY SOUTH-SOUTHWEST ACROSS THE ARKLATEX INTO EASTERN
   TEXAS...

   ...SUMMARY...
   Severe storms will continue from Texas to Iowa, with the greatest
   continuing across parts of the southern Plains into Arkansas and
   Louisiana.  Risk for widespread damaging winds and a few tornadoes
   will continue into this evening.

   ...Discussion...
   Aside from minor line adjustments to account for latest convective
   trends, only minimal changes to the outlook areas is being
   implemented at this time, as reasoning laid out in prior outlooks
   remains valid.

   An expansive area of convection continues from western Missouri
   south across western Arkansas, and then southwestward into the Hill
   Country of Texas, where damaging winds and embedded tornado risk
   continues.  Meanwhile, some redevelopment of storms remains possible
   over portions of southern Kansas and adjacent northwestern Oklahoma
   later this afternoon, where risk for large hail persists.

   ..Goss.. 05/18/2019

   .PREV DISCUSSION... /ISSUED 1126 AM CDT Sat May 18 2019/

   ...Central TX into AR...
   A large linear MCS has developed this morning, extending from
   southeast KS southward into northern and central TX.  The line of
   storms is moving into a strongly sheared and moderately unstable air
   mass, where surface dewpoints are currently in the mid 60s to lower
   70s, and effective helicity values are 200-300 m2/s2.  Locally
   damaging winds are expected to accompany the line as it moves
   eastward, along with transient QLCS tornado circulations.  The
   potential for discrete supercell development ahead of the line will
   increase this afternoon as daytime heating helps to destabilize the
   region ahead of the squall line.  This severe threat will persist
   through the day and into the evening as the storms track into much
   of AR and northwest LA.

   ...Northwest OK and south-central KS...
   The expansive cloud shield associated with the OK/TX MCS will move
   eastward, allowing a few hours of heating to occur over northwest OK
   and south-central KS.  Ample low-level moisture should return to
   this region, with a pocket of strong instability forecast to
   develop.  A consensus of 12z CAM guidance shows a few discrete
   supercells forming over this area late this afternoon.  While the
   risk area is rather small, strong deep-layer shear profiles and
   steep midlevel lapse rates suggest a significant risk of large hail
   with this activity.  Very large hail is possible.  Therefore have
   added an ENH risk and increased the hail probabilities for this
   region.

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