Aug 20, 2018 0100 UTC Day 1 Convective Outlook
Updated: Mon Aug 20 00:46:29 UTC 2018 (20180820 0100Z Day 1 shapefile | 20180820 0100Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180820 0100 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 28,785 1,757,746 Little Rock, AR...Springfield, MO...North Little Rock, AR...Conway, AR...Jacksonville, AR...
MARGINAL 31,059 2,133,409 Jonesboro, AR...Pine Bluff, AR...Hot Springs, AR...Oakville, MO...Wildwood, MO...
Probabilistic Tornado Graphic
20180820 0100 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 % 14,786 613,927 Springfield, MO...Ozark, MO...Nixa, MO...Harrison, AR...Mountain Home, AR...
2 % 19,454 1,302,485 Little Rock, AR...North Little Rock, AR...Conway, AR...Jacksonville, AR...Russellville, AR...
Probabilistic Damaging Wind Graphic
20180820 0100 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 % 28,427 1,715,707 Little Rock, AR...Springfield, MO...North Little Rock, AR...Conway, AR...Jacksonville, AR...
5 % 31,348 2,126,772 Jonesboro, AR...Pine Bluff, AR...Hot Springs, AR...Oakville, MO...Wildwood, MO...
Probabilistic Large Hail Graphic
20180820 0100 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
5 % 16,074 1,065,734 Little Rock, AR...North Little Rock, AR...Conway, AR...Jacksonville, AR...Russellville, AR...
   SPC AC 200046

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0746 PM CDT Sun Aug 19 2018

   Valid 200100Z - 201200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING
   ACROSS THE OZARK PLATEAU VICINITY...

   ...SUMMARY...
   Thunderstorms may continue to pose a risk for damaging wind gusts
   and perhaps a couple of additional tornadoes this evening across
   parts of southern Missouri and northern Arkansas.

   ...01Z Outlook Update...
   Models continue to indicate at least some further deepening of a
   lower/mid tropospheric cyclone across the northeast Kansas/northwest
   Missouri vicinity tonight.  This may occur as the stronger of a
   couple of mid-level speed maxima, within broader cyclonic mid-level
   flow, continues to dig from the central High Plains through the
   lower south central Plains.  This is preceded by a bit more modest
   speed maximum and associated impulse, which may weaken while
   pivoting northeastward through the lower Missouri Valley.

   Forcing for ascent and shear associated with the lead impulse are
   providing the support for the most significant convective
   development this evening, which  includes isolated supercells and a
   couple of small upscale growing clusters of storms now developing
   northeastward across parts of northwest Arkansas and southwestern
   Missouri.  This activity appears generally focused within lower/mid
   tropospheric warm advection along the trailing (southwestern) edge
   of rain-cooled air associated with weak preceding convection. 
   Substantive further modification of the rain-cooled air across
   central into southeast Missouri appears unlikely this evening. 
   However, a boundary layer air mass characterized by high moisture
   content and moderately large CAPE may remain supportive of
   thunderstorms capable of producing strong surface gusts and perhaps
   an additional tornado or two east of Springfield MO/Fort Smith AR
   through the Fort Leonard Wood MO/West Plains MO/Batesville AR/Little
   Rock AR areas into the 03-04Z time frame.

   Otherwise, isolated strong to severe storm development is ongoing
   beneath northwest mid-level flow across parts of central Kansas and
   to the southeast of the Sangre de Cristo Mountains.  However, this
   activity, and vigorous thunderstorms along a small eastward
   advancing cold pool now approaching the Beaufort/Hilton Head Island
   area of South Carolina, all seem likely to pose decreasing severe
   weather potential within the next hour or so.

   ..Kerr.. 08/20/2018

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z