Feb 20, 2018 1300 UTC Day 1 Convective Outlook
Updated: Tue Feb 20 13:00:35 UTC 2018 (20180220 1300Z Day 1 shapefile | 20180220 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180220 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 56,956 7,178,747 Dallas, TX...Arlington, TX...Plano, TX...Garland, TX...Irving, TX...
Probabilistic Tornado Graphic
20180220 1300 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
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20180220 1300 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 % 56,771 7,117,621 Dallas, TX...Arlington, TX...Plano, TX...Garland, TX...Irving, TX...
Probabilistic Large Hail Graphic
20180220 1300 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
No Risk Areas Forecast
   SPC AC 201300

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0700 AM CST Tue Feb 20 2018

   Valid 201300Z - 211200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
   ARK-LA-TEX AND OZARKS...

   ...SUMMARY...
   Thunderstorms are expected across a broad part of the south-central
   U.S. into the Midwest, with the possibility of a few strong to
   locally severe storms mainly late this afternoon into evening across
   the Ark-La-Tex vicinity and Ozarks.

   ...Synopsis...
   A highly amplified large-scale pattern will exist over the CONUS
   through the period, highlighted by a persistent longwave trough over
   the Western States and an upper ridge centered over the coastal
   Southeast States and nearby Atlantic Ocean. 

   ...ArkLaTex and Ozarks...
   Multiple corridors of scattered thunderstorms will continue to move
   northeastward today across the southern Plains/Ozarks to middle
   Mississippi Valley, both ahead of and behind a
   southeastward-accelerating strong cold front. This front should
   roughly extend from near the St Louis area southwestward to near
   Fort Smith, Arkansas and farther southwestward toward the
   Dallas-Fort Worth Metroplex vicinity by early evening (00Z).

   The large-scale pattern, with forcing for ascent largely maximized
   on the cool side of the southeastward-advancing front, typically
   supports a most-common hazard of locally heavy/persistent rainfall
   on the warm side of the boundary and wintry mixed precipitation on
   the cold side, with relatively limited or at least somewhat
   uncertain warm-sector severe potential otherwise. The aforementioned
   early-day scattered convection/cloud cover ahead of the front
   further casts uncertainty on the scope of today's severe risk.

   That said, some strong to locally severe storms are conceivable
   especially later this afternoon through early evening presuming some
   pre-frontal cloud breaks and modest destabilization. This currently
   appears plausible from the DFW Metroplex vicinity and nearby parts
   of North Texas northeastward into Arkansas and southern Missouri.
   Presuming at least modest pre-frontal destabilization, there will be
   the potential for aggregating/organizing northeastward-moving
   clusters and bows amidst very strong southwesterly winds (50 kt
   within the lowest 1-2 km AGL) just above the boundary layer. This
   could offer some potential for localized wind damage and possibly
   even a tornado mainly late this afternoon into early/mid evening.

   ..Guyer.. 02/20/2018

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z