SPC AC 131728

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1228 PM CDT Sun May 13 2018

   Valid 141200Z - 151200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
   SOUTHERN PLAINS TO THE MID MS VALLEY AND ACROSS PARTS OF THE OHIO
   VALLEY...

   ...SUMMARY...
   Severe thunderstorms, capable of damaging winds and large hail, will
   be possible Monday afternoon and evening from parts of the southern
   Plains northeastward to the mid Mississippi Valley. Elsewhere, a few
   severe storms will be possible from the mid/upper Ohio Valley
   eastward to the Mid-Atlantic. The main threat with these cells will
   be damaging wind.

   ...Southern Plains to the mid Mississippi Valley...
   Severe/convective evolution appears somewhat uncertain across
   portions of the region on Monday. Within a regime of approximately
   25-40 kt 500mb southwesterlies overlying the southern Plains and
   Missouri Valley, several weak/convectively augmented impulses will
   likely be transiting northeastward through the day. Focused
   ascent/warm advection ahead of each of these impulses will likely
   encourage convective initiation along both a dry line extending
   southward from southern Kansas into western Oklahoma/Texas, as well
   as a front extending to the northeast towards the Kansas City metro
   area and points east/northeast. The strongest flow aloft (and
   potential for greatest storm organization) will likely exist from
   northeast Kansas to the mid Mississippi Valley. Furthermore, a nose
   of focused warm advection will likely be placed in this zone as
   well, such that scattered convection is expected by afternoon. In
   turn, steep mid-level lapse rates (giving rise to moderate/strong
   buoyancy) should yield a few multicell clusters, with embedded
   supercell elements, primarily capable of damaging winds and large
   hail near/south of the front. To its north, large hail will be the
   primary threat.

   With south/southwestward extent, decreasing flow aloft will likely
   reduce storm organization. Nonetheless, favorable heating/lapse
   rates should encourage a damaging wind threat with any deeper cores
   during the afternoon/evening.

   ...Ohio Valley to the Mid Atlantic...
   Considerable uncertainty also exists across this region on Monday.
   It is likely that some residual convective system will be ongoing
   across parts of Indiana and Ohio Monday morning, resulting from
   overnight convection generating in northern Illinois. With the Ohio
   Valley remaining on the edge of a plume of steep mid-level lapse
   rates, any stronger surface-based convection will likely be capable
   of damaging winds. Additionally, related to this convective system,
   a mid-level speed maximum will be transiting the Midwest through the
   morning/mid-day hours, which should assist some with convective
   system maintenance and downward momentum transport. 

   Uncertainty remains in that there is some spatial offset between the
   zone of greatest destabilization (due to timing of the
   wave/potential MCS) over the Mid-Atlantic and corridor of better
   mid-level flow over the Midwest. A slight risk has been introduced
   across the mid/upper Ohio Valley, where the highest confidence
   exists in the potential for an ongoing convective system, capable of
   damaging winds, during the first half of the day. Farther southeast,
   a decrease in mid-level flow/expected organization, as well as
   greater uncertainty with downstream convective development,
   precludes an upgrade at this time. However, if confidence in a more
   robust, east/southeastward propagating system increases, the slight
   risk may be expanded southeast accordingly.

   ...MAXIMUM RISK BY HAZARD...
   Tornado:   2%     - Marginal
   Wind:     15%     - Slight
   Hail:     15%     - Slight

   ..Picca.. 05/13/2018

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z