Aug 14, 2019 0600 UTC Day 1 Convective Outlook
Updated: Wed Aug 14 05:46:05 UTC 2019 (20190814 1200Z Day 1 shapefile | 20190814 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20190814 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 31,302 170,336 Scottsbluff, NE...Sterling, CO...Torrington, WY...
SLIGHT 63,121 416,001 Rapid City, SD...North Platte, NE...Gillette, WY...Fort Morgan, CO...Spearfish, SD...
MARGINAL 359,662 25,239,378 Denver, CO...New Orleans, LA...Virginia Beach, VA...Colorado Springs, CO...Aurora, CO...
Probabilistic Tornado Graphic
20190814 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
5 % 30,344 168,767 Scottsbluff, NE...Sterling, CO...Torrington, WY...
2 % 62,710 448,354 Rapid City, SD...North Platte, NE...Gillette, WY...Fort Morgan, CO...Spearfish, SD...
Probabilistic Damaging Wind Graphic
20190814 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 % 71,617 418,154 North Platte, NE...Scottsbluff, NE...Sterling, CO...Fort Morgan, CO...Torrington, WY...
5 % 383,129 25,909,335 Denver, CO...New Orleans, LA...Virginia Beach, VA...Colorado Springs, CO...Aurora, CO...
Probabilistic Large Hail Graphic
20190814 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
SIG SEVERE 61,829 439,156 Rapid City, SD...Scottsbluff, NE...Sterling, CO...Fort Morgan, CO...Spearfish, SD...
30 % 32,054 170,829 Scottsbluff, NE...Sterling, CO...Torrington, WY...
15 % 63,183 424,721 Rapid City, SD...North Platte, NE...Gillette, WY...Fort Morgan, CO...Spearfish, SD...
5 % 141,670 4,074,317 Denver, CO...Colorado Springs, CO...Aurora, CO...Fort Collins, CO...Thornton, CO...
   SPC AC 140546

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1246 AM CDT Wed Aug 14 2019

   Valid 141200Z - 151200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
   CENTRAL HIGH PLAINS...

   ...SUMMARY...
   Scattered severe thunderstorms with very large hail and damaging
   winds are expected across the central High Plains this afternoon and
   evening. A few strong storms may be noted across the Gulf Coast to
   the southern Middle Atlantic.

   ...Central High Plains...

   Large-scale pattern is forecast to change little across the western
   US through the day1 period. Broad upper ridging will hold across the
   Great Basin with seasonally strong mid-level flow extending from
   WA/OR, across the northern Rockies into the central Plains. It's not
   entirely clear whether a weak disturbance will affect the High
   Plains later today, however steep mid-level lapse rates persist
   across this region within broad northwesterly flow regime. Strong
   diurnal heating will once again contribute to significant buoyancy
   in the lee of the Rockies prior to convective initiation. In the
   absence of a meaningful short-wave trough, it appears surface
   heating will prove instrumental in thunderstorm development. It
   appears thunderstorms should develop by 21-22z as convective
   temperatures are breached. Latest CAMs support this scenario with
   scattered convection developing by late afternoon from southeast
   MT-eastern WY/CO. Forecast soundings across this region strongly
   favor supercells and steep lapse rates/bulk shear appear supportive
   of very large hail. Local hail algorithm generates hail in excess of
   2" with robust convection across the High Plains again this
   afternoon. Given the stronger shear expected later today, compared
   to Tuesday, there is reason to believe supercells may maintain their
   character a bit longer than yesterday. For these reasons have
   increased severe probabilities to account for a potentially more
   widespread severe event from eastern WY into eastern CO/northwest
   KS. While initial activity should prove productive in generating
   hail, damaging winds will become more common if an MCS evolves later
   in the evening along nose of LLJ.

   ...Gulf States/Southeast-Middle Atlantic Coast...

   Weak surface boundary will sag southeast during the day, extending
   from VA-Carolinas-central Gulf States by 18z. This boundary will
   serve as the focus for convection within a high-PW air mass
   characterized by generally weak shear. While lapse rates are not
   particularly steep, Isolated damaging winds could be noted with
   short-lived wet micro bursts.

   ..Darrow/Cook.. 08/14/2019

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