Mar 23, 2017 0600 UTC Day 1 Convective Outlook
Updated: Thu Mar 23 05:34:56 UTC 2017 (20170323 1200Z Day 1 shapefile | 20170323 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170323 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 120,702 1,732,854 Lubbock, TX...Amarillo, TX...Midland, TX...Grand Island, NE...Kearney, NE...
MARGINAL 177,750 11,875,731 Omaha, NE...Miami, FL...Wichita, KS...Lincoln, NE...Hialeah, FL...
Probabilistic Tornado Graphic
20170323 1200 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 % 54,860 527,212 Amarillo, TX...Garden City, KS...Dodge City, KS...North Platte, NE...Liberal, KS...
Probabilistic Damaging Wind Graphic
20170323 1200 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 % 93,502 1,357,124 Lubbock, TX...Amarillo, TX...Midland, TX...Garden City, KS...Dodge City, KS...
5 % 113,653 8,607,202 Miami, FL...Wichita, KS...Hialeah, FL...Fort Lauderdale, FL...Pembroke Pines, FL...
Probabilistic Large Hail Graphic
20170323 1200 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
15 % 90,848 1,109,870 Amarillo, TX...Grand Island, NE...Kearney, NE...Garden City, KS...Dodge City, KS...
5 % 149,293 10,597,917 Omaha, NE...Miami, FL...Lincoln, NE...Hialeah, FL...Lubbock, TX...
   SPC AC 230534

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1234 AM CDT Thu Mar 23 2017

   Valid 231200Z - 241200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS
   AFTERNOON AND EVENING ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE
   HIGH PLAINS...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS
   SURROUNDING AREAS OF THE CENTRAL AND SOUTHERN PLAINS INTO THE MIDDLE
   MISSOURI VALLEY...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TODAY ACROSS
   PARTS OF SOUTHERN FLORIDA...

   ...SUMMARY...
   Strong thunderstorms are expected from parts of the central and
   southern Plains into the mid Missouri Valley late this afternoon
   into tonight, accompanied by potential for severe hail and damaging
   surface gusts.  Thunderstorms with a risk for severe wind and hail
   are also possible across parts of southern Florida.

   ...Synopsis...
   Much of the nation will remain under the influence of split
   westerlies emanating from the mid-latitude Pacific.  Within this
   regime, one prominent northern stream trough is forecast to continue
   to progress away from the Atlantic Seaboard.  As it does, models
   suggest remnant southern stream troughing will linger over the
   Bahamas/parts of southern Florida and the Caribbean, while short
   wave ridging builds to its northwest (across the Southeast), ahead
   of a more significant southern stream short wave trough forecast to
   progress east of the southern Great Basin/lower Colorado Valley,
   through the southern Rockies/High Plains by 12z Friday.

   In association with this latter feature, models generally indicate
   that significant surface cyclogenesis will initiate across parts of
   northeastern Colorado during the day today, before redeveloping
   southeastward into western Kansas tonight, in closer proximity to a
   lower/mid tropospheric cyclone developing within the larger-scale
   trough as it crosses the southern Rockies.  This should be
   accompanied by considerable strengthening of southerly low-level
   flow through portions of the Plains into Mississippi Valley,
   particularly by tonight, when speeds around the 850 mb level are
   expected to reach 50-70 kt across much of the southern into central
   Plains.

   Despite the favorable evolving large-scale flow, a substantive
   return flow of moisture from the Gulf of Mexico appears unlikely
   during this period due to recent drying across much of the Gulf
   region.  This probably will limit the extent of the convective
   potential today and tonight.  However, steep mid-level lapse rates
   associated with a plume of elevated mixed-layer air emerging from
   the southern Rockies/Mexican Plateau region may contribute to
   sufficient destabilization to support at least some risk for severe
   storm activity across the central and southern Plains into the mid
   Missouri Valley.  A remnant plume of elevated mixed-layer air, which
   has advected considerably south and east of the Plains, may also
   contribute to some severe weather potential across parts of southern
   Florida.

   ...Central and southern Plains into mid Missouri Valley...
   The lack of substantive deep return flow of moisture, coupled with
   downward mixing of dry lower/mid tropospheric air, will be
   problematic with regard to severe thunderstorm potential today. 
   Guidance continues to suggest that the most substantive
   boundary-layer moistening may be confined to a narrow corridor along
   the lee surface trough across parts of western Kansas (perhaps as
   far south as parts of the Texas/Oklahoma Panhandle region) into
   southwestern Nebraska by the 21-23Z time frame this afternoon.  Even
   this may be characterized by surface dew points only on the order of
   55-60F.  However, beneath steep mid-level lapse rates, this may be
   sufficient for a corridor of mixed-layer CAPE up to around 1000
   J/kg, as a 50-70 kt southwesterly mid-level jet streak noses across
   the region.

   While the primary upper impulse may still be lagging near or to the
   west of the Rockies, the environment along/east of the sharpening
   dryline probably will be conducive to discrete supercell
   development.  Some risk for at least weak/brief tornadoes may exist
   with initial development, but severe hail may be the most prominent
   risk with this activity as it develops northeastward/eastward
   through early evening.

   As the main impulse/developing mid-level circulation emerges from
   the intermountain region this evening, storms with severe hail
   potential may become focused within an area of strengthening
   low-level warm advection across north central and northeastern
   Nebraska.  Additional storm development may become focused on the
   leading edge of stronger lower/mid-tropospheric cooling, from parts
   of western Kansas into the Texas South Plains.  In the presence of
   intensifying environmental wind fields, potentially damaging wind
   gusts seem likely to be the primary threat with an evolving squall
   line.  This could continue into the overnight hours, eastward toward
   the lower Plains, but it remains unclear at this time if instability
   will remain sufficient to support vigorous convection east of
   western Kansas/Oklahoma and northwest Texas.

   ...South Florida...
   Relatively steep mid-level lapse rates associated with remnants of a
   plume of elevated mixed-layer air, and cold air aloft, could
   contribute to an environment conducive to storms capable of
   producing severe hail and wind gusts.  This may be aided by forcing
   for ascent associated with an impulse digging into lingering upper
   troughing across the region.  However, this remains at least one
   point of considerable spread among the model output, and severe
   weather potential remains too uncertain for more than 5 percent
   severe probabilities at this time.

   ..Kerr/Dean.. 03/23/2017

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z