Jun 11, 2018 1630 UTC Day 1 Convective Outlook
Updated: Mon Jun 11 16:29:57 UTC 2018 (20180611 1630Z Day 1 shapefile | 20180611 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180611 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 53,489 4,703,795 Kansas City, MO...Omaha, NE...Wichita, KS...Overland Park, KS...Kansas City, KS...
SLIGHT 99,691 6,175,875 Oklahoma City, OK...Tulsa, OK...Lincoln, NE...Des Moines, IA...Sioux Falls, SD...
MARGINAL 328,318 36,677,398 Charlotte, NC...Nashville, TN...Raleigh, NC...St. Louis, MO...Louisville, KY...
Probabilistic Tornado Graphic
20180611 1630 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 % 34,680 1,932,044 Omaha, NE...Sioux Falls, SD...Sioux City, IA...Council Bluffs, IA...Bellevue, NE...
2 % 56,149 4,264,377 Kansas City, MO...Wichita, KS...Lincoln, NE...Overland Park, KS...Kansas City, KS...
Probabilistic Damaging Wind Graphic
20180611 1630 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 % 41,180 4,135,077 Kansas City, MO...Omaha, NE...Wichita, KS...Overland Park, KS...Kansas City, KS...
15 % 109,560 6,688,963 Oklahoma City, OK...Tulsa, OK...Lincoln, NE...Des Moines, IA...Sioux Falls, SD...
5 % 326,420 36,170,365 Charlotte, NC...Nashville, TN...Raleigh, NC...St. Louis, MO...Louisville, KY...
Probabilistic Large Hail Graphic
20180611 1630 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 29,451 1,932,601 Omaha, NE...Lincoln, NE...Topeka, KS...Council Bluffs, IA...Bellevue, NE...
30 % 29,241 1,725,741 Omaha, NE...Topeka, KS...Sioux City, IA...Council Bluffs, IA...Bellevue, NE...
15 % 68,449 4,520,383 Kansas City, MO...Wichita, KS...Lincoln, NE...Overland Park, KS...Kansas City, KS...
5 % 162,496 11,453,816 Oklahoma City, OK...Tulsa, OK...St. Louis, MO...Des Moines, IA...Springfield, MO...
   SPC AC 111629

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1129 AM CDT Mon Jun 11 2018

   Valid 111630Z - 121200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS LOWER/MID-MO
   VALLEY...

   ...SUMMARY...
   Scattered severe storms are most likely across parts of the Lower to
   Mid-Missouri Valley during the late afternoon and evening. Very
   large hail, damaging wind gusts, and a few tornadoes are possible.

   ...Lower/Mid-MO Valley to Ozark Plateau...
   A surface cyclone is centered over southeast SD with a cold front
   extending southwest into the southern High Plains. This boundary
   should gradually progress east with the surface low tracking
   southeast where the front occludes and intersects a warm front near
   the MO/IA border. Upper 60s to lower 70s boundary-layer dew points
   are prevalent within the warm sector south towards central/eastern
   OK. This moisture combined with nearly cloud-free insolation along
   with rather steep mid-level lapse rates, will support a large plume
   of very large buoyancy with MLCAPE of 3000-4000 J/kg.

   Initial storm development is anticipated near the surface cyclone
   over the Mid-MO Valley. The strong instability will compensate for
   marginally favorable wind profiles with slow storm motions. This
   should yield a cluster mode with embedded supercells from western IA
   to northeast KS. Very large hail and a few tornadoes will be
   possible within this corridor, mainly between 21-01Z. Thereafter,
   thunderstorm outflow should become more pervasive and upscale growth
   into one or more MCSs will be largely cold pool driven given only
   modest low-level warm advection tonight. As such, confidence is low
   in how convective evolution will play out. Persistent/backbuilding
   storms are possible to the southwest along the front towards
   south-central KS. Another scenario is for a southward-propagating
   MCS towards the Ozark Plateau, which could result in a more
   widespread severe wind threat. With storm-scale processes being the
   predominant driver of severe risk tonight, will broaden the
   probabilities to account for the uncertainty, and defer on greater
   coverage/intensity upgrades for later outlooks.

   ...Southern IL to KY...
   Convection is ongoing from central IL east to the Upper OH Valley in
   association with weak low-level warm advection and decaying MCVs.
   This convection will help reinforce the stalled front from southern
   IL across KY, which should focus additional storm development this
   afternoon as the boundary layer to the south destabilizes. With weak
   deep-layer shear and 700 mb westerlies decreasing, the potential for
   an organized multicell cluster producing damaging winds appears low,
   but isolated damaging winds are possible. 

   ...Carolinas...
   A cold front has reached parts of central NC/SC. Scattered storms
   will develop along this boundary this afternoon, with moderate
   buoyancy (MLCAPE of 1500-2000 J/kg) common ahead of it. Vertical
   shear is very weak, but given the expected coverage of pulse storms,
   will maintain low wind probabilities for short-lived downbursts.

   ..Grams/Gleason.. 06/11/2018

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z