Mar 28, 2017 1300 UTC Day 1 Convective Outlook
Updated: Tue Mar 28 12:54:16 UTC 2017 (20170328 1300Z Day 1 shapefile | 20170328 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170328 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 17,148 404,957 Wichita Falls, TX...Lawton, OK...Altus, OK...Burkburnett, TX...Vernon, TX...
ENHANCED 67,266 2,390,618 Oklahoma City, OK...Abilene, TX...Norman, OK...San Angelo, TX...Edmond, OK...
SLIGHT 78,985 11,664,481 Dallas, TX...Austin, TX...Fort Worth, TX...Tulsa, OK...Arlington, TX...
MARGINAL 150,003 16,572,960 San Antonio, TX...Charlotte, NC...Virginia Beach, VA...Raleigh, NC...Norfolk, VA...
Probabilistic Tornado Graphic
20170328 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
10 % 23,981 635,480 Abilene, TX...Wichita Falls, TX...Lawton, OK...Duncan, OK...Altus, OK...
5 % 45,326 6,480,301 Fort Worth, TX...Oklahoma City, OK...Arlington, TX...Plano, TX...Irving, TX...
2 % 69,879 3,728,884 Dallas, TX...Garland, TX...Lubbock, TX...Mesquite, TX...Waco, TX...
Probabilistic Damaging Wind Graphic
20170328 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
30 % 61,457 2,643,319 Oklahoma City, OK...Abilene, TX...Norman, OK...Wichita Falls, TX...Lawton, OK...
15 % 72,606 11,340,312 Dallas, TX...Austin, TX...Fort Worth, TX...Tulsa, OK...Arlington, TX...
5 % 138,950 15,260,393 San Antonio, TX...Charlotte, NC...Virginia Beach, VA...Raleigh, NC...Norfolk, VA...
Probabilistic Large Hail Graphic
20170328 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
SIG SEVERE 52,453 946,793 Abilene, TX...Wichita Falls, TX...Lawton, OK...San Angelo, TX...Duncan, OK...
45 % 17,148 404,957 Wichita Falls, TX...Lawton, OK...Altus, OK...Burkburnett, TX...Vernon, TX...
30 % 47,442 800,288 Abilene, TX...San Angelo, TX...Ardmore, OK...Duncan, OK...Brownwood, TX...
15 % 74,343 9,399,552 Dallas, TX...Fort Worth, TX...Oklahoma City, OK...Arlington, TX...Plano, TX...
5 % 138,216 16,542,307 San Antonio, TX...Austin, TX...Virginia Beach, VA...Tulsa, OK...Raleigh, NC...
   SPC AC 281254

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0754 AM CDT Tue Mar 28 2017

   Valid 281300Z - 291200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS NORTHWEST TX AND
   FAR SOUTHWEST OK...

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTRAL OK TO
   THE EDWARDS PLATEAU...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF OK/TX...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF
   SOUTHERN GREAT PLAINS...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS VA/NC...

   ...SUMMARY...
   Numerous severe storms are expected across the southern Great
   Plains, mainly after 2 pm CDT into tonight. Very large hail,
   tornadoes, and damaging winds will be possible.

   ...Synopsis...
   Vigorous shortwave trough over eastern AZ will shift east and reach
   the southern High Plains by early Wednesday. Surface cyclone over
   the Permian Basin will move northeast into northwest TX and become
   quasi-stationary. By late afternoon, a bulging dryline will sharpen
   to the south of this cyclone. A Pacific cold front will overtake the
   dryline in west Texas this evening and sweep east into central Texas
   overnight. A warm front will advance across northern TX and should
   arc from the cyclone across the Red River into eastern OK by 00Z. 

   ...Southern Great Plains...
   Rich gulf moisture characterized by mean mixing ratios to 14 g/kg
   per 12Z Del Rio, Corpus Christi, and Lake Charles RAOBs has become
   prevalent in the broadening warm sector over central/south TX. While
   diurnal mixing may yield pockets of lower dew points over
   central/east TX, a plume of lower to middle 60s surface dew points
   will be sustained along the dryline and warm front. Beneath a stout
   EML with very steep lapse rates to 9 degree C/km from 700-500 mb per
   12Z Del Rio RAOB, moderate to large buoyancy is expected ahead of
   the dryline. MLCAPE should reach 1500-3000 J/kg across the Edwards
   Plateau and Big Country. The leading edge of 50-kt 500-mb
   south-southwesterlies will spread east over this instability axis by
   late afternoon, yielding an environment favorable for supercells.

   While elevated storms will increase over the Texas Panhandle through
   midday, surface-based storms should develop towards mid-afternoon
   near the surface cyclone. Scattered storms will form farther south
   along the dryline late afternoon, with WAA-driven storms possible
   farther east over north-central TX. Initially discrete supercell
   mode should favor very large hail and localized severe wind gusts.
   Relatively high confidence in the coverage and location of storms
   warrants an upgrade to a hail-driven moderate risk from the Big
   Country into southwest OK. A few tornadic storms appear probable in
   this similar corridor. However, the temporal overlap of discrete
   cells with enlarging hodographs may be relatively short in the open
   warm sector. Low-level hodographs will be quite enlarged along the
   warm front, but should be coincident with modest low-level lapse
   rates and predominant cluster to linear mode. As such, an upgrade to
   15 percent tornado probabilities does not appeared warranted this
   outlook. 

   As storms mature, upscale growth into lines with embedded bowing
   segments is expected due to both the strong large-scale ascent and
   meridional flow aloft generally paralleling the dryline. These
   linear bands should accelerate northeast into southern/central
   Oklahoma during the evening, with attendant risks for damaging
   winds, hail, and a couple tornadoes. 

   Farther south over the Edwards Plateau, initially isolated to widely
   scattered late afternoon/early evening storms should become
   widespread in coverage during mid-late evening as the Pacific front
   merges with the dryline. This should result in a predominant risk of
   large hail transitioning quickly to strong to severe wind gusts. An
   extensive squall line will likely evolve east overnight with an
   isolated severe risk spreading into central TX. 

   ...VA/NC...
   A dampening shortwave impulse over WV will shift off the VA/NC coast
   by mid-evening. Ongoing showers and isolated storms will subdue
   destabilization early in the diurnal heating cycle. However, by late
   afternoon, widely scattered storms should develop ahead of the
   impulse. Increased veering of the wind profile with height should
   foster mainly discrete cells, some of which should weakly rotate.
   Isolated severe hail and damaging wind appear possible.

   ..Grams/Dial.. 03/28/2017

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