May 21, 2020 1630 UTC Day 1 Convective Outlook
Updated: Thu May 21 16:01:50 UTC 2020 (20200521 1630Z Day 1 shapefile | 20200521 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20200521 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 60,728 728,168 Abilene, TX...San Angelo, TX...Garden City, KS...Dodge City, KS...Big Spring, TX...
MARGINAL 227,409 19,327,869 Dallas, TX...Fort Worth, TX...Oklahoma City, OK...Arlington, TX...Wichita, KS...
Probabilistic Tornado Graphic
20200521 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
5 % 9,604 106,310 Garden City, KS...Liberal, KS...
2 % 65,669 4,751,221 Dallas, TX...Plano, TX...Garland, TX...Mesquite, TX...Fayetteville, NC...
Probabilistic Damaging Wind Graphic
20200521 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
15 % 60,537 714,678 Abilene, TX...San Angelo, TX...Garden City, KS...Dodge City, KS...Big Spring, TX...
5 % 228,496 19,337,759 Dallas, TX...Fort Worth, TX...Oklahoma City, OK...Arlington, TX...Wichita, KS...
Probabilistic Large Hail Graphic
20200521 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
SIG SEVERE 20,843 188,505 Garden City, KS...Dodge City, KS...Liberal, KS...Woodward, OK...
15 % 60,676 718,062 Abilene, TX...San Angelo, TX...Garden City, KS...Dodge City, KS...Big Spring, TX...
5 % 132,428 4,850,977 Orlando, FL...Coral Springs, FL...Midland, TX...Odessa, TX...Weston, FL...
   SPC AC 211601

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1101 AM CDT Thu May 21 2020

   Valid 211630Z - 221200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
   THE CENTRAL AND SOUTHERN HIGH PLAINS...

   ...SUMMARY...
   A few severe thunderstorms are expected this afternoon and evening
   in the southern and central High Plains. Other isolated severe
   thunderstorms may occur in the Carolinas and Florida.

   ...Western KS and Vicinity...
   Southwest flow aloft is present today over most of the Plains
   states, with weak midlevel height falls expected to spread into
   parts of KS and the TX Panhandle later today.  A weak surface low is
   currently analyzed over western KS, and should stay stationary or
   move slowly southward this afternoon as a front sags southward
   across eastern CO.  The capping inversion is strong this morning,
   but is forecast to weaken rapidly by mid-afternoon as a combination
   of large scale forcing, daytime heating, and low-level moisture
   return occur.

   Current indications are that storms will initiate along the surface
   cold front, and near the surface low/triple-point, over western KS
   before 21z.  Forecast soundings suggest steep midlevel lapse rates
   and MLCAPE over 2000 J/kg.  Large hail will be the primary threat
   with initial storms, with a risk of isolated very large hail. 
   Vertical shear profiles are not particularly strong, but should be
   sufficient for a few supercells during the late afternoon.  Activity
   will likely congeal into a bowing MCS after dark, spreading into
   southwest KS and northwest OK with a risk of damaging winds.

   ...Central TX...
   Water vapor imagery shows a shortwave trough moving eastward across
   central TX this morning.  Clear skies and veered low-level winds are
   present to the west of the trough across west TX.  By
   late-afternoon, full sunshine will lead to strong instability and a
   deeply mixed boundary layer along the dryline near Abilene/San
   Angelo.  However, convergence will be quite weak and convective
   initiation is highly uncertain.  Will maintain portions of the
   ongoing SLGT risk due to a conditional risk of hail and damaging
   wind gusts if storms can form.  But confidence is low for this area.

   ...FL...
   Strong heating is occurring this morning over the FL peninsula,
   where dewpoints in the 70s and rather cool temperatures aloft will
   yield afternoon MLCAPE values over 2500 J/kg.  Thunderstorms are
   expected to form first over south FL, then develop northward along
   the instability axis.  Wet microbursts capable of gusty/damaging
   wind gusts and occasional hail appear to be the main risks. 
   Midlevel winds and low-level shear are weak, limiting convective
   organization and the risk of a more robust severe event.

   ...Carolinas...
   Scattered afternoon thunderstorms are expected over the eastern
   Carolinas, where scattered breaks in the clouds and dewpoints in the
   60s will develop later today.  Easterly surface winds along/north of
   a warm front may lead to transient supercell structures capable of
   gusty winds or even a brief tornado.  However, weak flow aloft
   should limit overall several potential.

   ..Hart/Squitieri.. 05/21/2020

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