Jun 20, 2018 0600 UTC Day 2 Convective Outlook
Updated: Wed Jun 20 05:44:10 UTC 2018 (20180620 0600Z Day 2 shapefile | 20180620 0600Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180620 0600 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 226,498 11,829,548 Memphis, TN...St. Louis, MO...Shreveport, LA...Little Rock, AR...Springfield, IL...
Probabilistic Graphic
20180620 0600 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Day 2 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 227,841 11,932,592 Memphis, TN...St. Louis, MO...Shreveport, LA...Little Rock, AR...Springfield, IL...
   SPC AC 200544

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1244 AM CDT Wed Jun 20 2018

   Valid 211200Z - 221200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
   MIDDLE AND LOWER MISSISSIPPI VALLEY...ACROSS CENTRAL MONTANA...AND
   OVER PARTS OF THE SOUTHERN HIGH PLAINS...

   ...SUMMARY...
   Scattered severe hail and wind is possible Thursday across parts of
   the middle and lower Mississippi Valley. Isolated hail is also
   possible across parts of the southern High Plains and northern
   Rockies.

   ...Synopsis...
   An upper low will travel southeastward across MO, with a belt of
   50-60 kt midlevel northwesterly winds moving from the central Plains
   into the lower MS Valley. At the surface, low pressure will develop
   toward the middle MS Valley. A cold front will extend southwestward
   toward the Arklatex by 00Z, with a warm front extending east across
   the OH Valley. To the west, an upper high will be centered over AZ,
   with a low-amplitude shortwave flattening the ridge over the
   northern Rockies where a cold front moving into MT and WY. 

   ...Mid to lower MS Valley...
   Cool air aloft with the upper trough and ample low-level moisture
   will lead to areas of 1000-2000 J/kg MUCAPE from TX to IL.
   Complicating this forecast scenario will be widespread precipitation
   and clouds early in the day. However, a plume of heating and
   steepening low-level lapse rates is expected to develop mainly along
   and west of the MS river. Given cool temperatures aloft, an arc of
   diurnal re-development is expected. Hail and wind will be possible,
   and portions of the area may eventually be upgraded to a Slight Risk
   once predictability issues decrease in later outlooks.

   ...Central and southwest MT and vicinity...
   Lift associated with the upper trough and cold front will lead to
   scattered storms during the afternoon. Steep lapse rates and
   lengthening hodographs will favor cells and/or small bows capable of
   large hail or damaging winds.

   ...Southern High Plains...
   Strong heating along with 50s F dewpoints will lead to a pocket of
   1500 J/kg MUCAPE by late afternoon. Weak southeasterly surface winds
   will lead to sufficient convergence for isolated afternoon storms
   mainly over northeast NM. Straight hodographs and northwest flow
   aloft will favor slow, southeastward-moving cells capable of
   marginally severe hail.

   ...MAXIMUM RISK BY HAZARD...
   Tornado:   2%     - Marginal
   Wind:      5%     - Marginal
   Hail:      5%     - Marginal

   ..Jewell.. 06/20/2018

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z