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 %
48,950
513,582
Grand Island, NE...Kearney, NE...Norfolk, NE...Hastings, NE...Columbus, NE...
Probabilistic Damaging Wind 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
SIG SEVERE
16,471
80,352
Garden City, KS...
15 %
57,502
558,395
Grand Island, NE...Kearney, NE...Garden City, KS...Dodge City, KS...Hastings, NE...
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
29,057
359,167
Grand Island, NE...Kearney, NE...Hastings, NE...Columbus, NE...Lexington, NE...
15 %
61,108
642,087
Grand Island, NE...Kearney, NE...Garden City, KS...Norfolk, NE...Hastings, NE...
5 %
250,144
15,721,027
Dallas, TX...Fort Worth, TX...Oklahoma City, OK...Omaha, NE...Arlington, TX...
SPC AC 161629
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Sun Aug 16 2020
Valid 161630Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EASTERN NE TO
CENTRAL HIGH PLAINS...
...SUMMARY...
Scattered severe storms with large hail and damaging winds, some of
which could be significant, will be most likely during the late
afternoon and evening from eastern Nebraska to the central High
Plains.
...NE/KS/eastern CO...
Ongoing elevated convection from eastern KS to northwest OK is
expected to largely demarcate the southeast extent of the organized
severe risk later today. A rich low-level moisture plume arcs around
this activity from the TX/OK Panhandles northward into central NE.
This plume resides beneath the eastern extent of steep mid-level
lapse rates from an elevated mixed-layer around the eastern
periphery of the stout anticyclone over the southern Great Basin.
Strong to extreme buoyancy (MLCAPE of 3000-4500 J/kg) is expected by
peak heating afternoon from south-central NE to western KS.
A weak reinforcing cold front sagging south across NE and a lee
trough in eastern CO should be foci for scattered late afternoon
thunderstorms. The region will lie in the gradient between stronger
mid-level northwesterlies over the Upper Midwest and weak flow over
the Rockies. Sufficient deep-layer shear should exist given the
robust thermodynamic environment to support supercells, at least a
couple of which should produce very large hail. Storms that form on
the boundary in NE should develop south or southwestward through
this evening, with some potential for upscale growth into a small
MCS across western KS with a risk for isolated significant severe
gusts. Further cell/cluster mergers may sustain an isolated severe
wind/hail threat lingering through tonight.
...Southern Great Plains to Lower MS Valley...
A plume of mid 70s surface dew points and hot temperatures warming
well through the 90s will fuel an extremely unstable air mass across
southern OK into the ArkLaMiss ahead of a weak cold front. While
guidance varies greatly in the degree of convective development
along the weakly convergent boundary this afternoon, scattered
thunderstorms are possible. Deep-layer wind fields will be weak
characterized by 10-20 kts at 500-mb in the late afternoon. But
given the northerly component to the flow and the very large MLCAPE,
the setup may yield loosely-organized multicell clusters with
isolated damaging/severe outflow gusts and hail possible across a
broad region of the south-central states.
For further short-term discussion regarding the threat in OK, please
see MCD 1508.
...Northern CA to OR...
Scattered elevated thunderstorms within mid-level moisture advection
around the southern Great Basin anticyclone are ongoing coastal
central CA into the northern Sacramento Valley. A leading MCV
appears to have developed and is advertised by morning model
guidance to rapidly translate north across northern CA into central
OR through this evening. The convection should eventually root into
the boundary layer later this afternoon in response to steepening
low-level lapse rates. The storms may produce isolated severe gusts
given the steep lapse rate profiles and potential for downward
momentum transfer of 35-50 kt mid-level southwesterlies. Meager
buoyancy should be a limiting factor to a greater severe risk.
...Southern AZ...
An MCV over the northern Gulf of CA in the wake of convection that
decayed overnight in Sonora will translate west away from the region
today. Latest water vapor imagery is suggestive of weak
mid/upper-level subsidence upstream. Nevertheless, PW values
initially from 1.25-1.5 inches as sampled in 12Z Tucson and Phoenix
soundings should be sufficient for isolated late afternoon
thunderstorms over the higher terrain. 10-20 kt mid-level easterlies
around the southern Great Basin anticyclone should be adequate for a
few cells and a brief cluster to spread west-southwest towards the
lower deserts with an accompanying threat of isolated strong/severe
outflow gusts.
..Grams/Wendt.. 08/16/2020
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