SPC AC 181730

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1230 PM CDT Wed May 18 2022

   Valid 191200Z - 201200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE UPPER MIDWEST...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
   MID MISSISSIPPI VALLEY INTO THE LOWER OHIO VALLEY AND CAROLINAS...

   ...SUMMARY...
   Scattered severe thunderstorms appear likely late Thursday afternoon
   into Thursday night over portions of the Upper Midwest. Very large
   hail, damaging wind gusts, and few tornadoes all appear possible.
   Additional strong to severe thunderstorms should occur from southern
   Missouri eastward through the lower Ohio Valley and into the
   Carolinas.

   ...Synopsis...
   A positively tilted upper trough will move eastward across the
   north-central states and eventually the Upper Midwest on Thursday.
   An enhanced west-southwesterly mid/upper-level jet will accompany
   this upper trough. A surface low is forecast to deepen as it
   develops eastward from the northern Plains to the Upper Midwest by
   Thursday evening. Rich low-level moisture should return northward as
   a warm front lifts across the Midwest, mid MS Valley, and OH Valley.
   A dryline should extend southward from the surface low over much of
   the central/southern Plains.

   ...Upper Midwest...
   A cap should inhibit thunderstorm initiation through much of the day
   across the Upper Midwest. Still, latest guidance suggests that the
   airmass along/south of the warm front will become at least
   moderately unstable by late Thursday afternoon, as ample diurnal
   heating of a moistening low-level airmass occurs and steep mid-level
   lapse rates overspread the warm sector. Strong deep-layer shear (50+
   kt) will likely be present as well as the mid/upper-level jet
   approaches from the west. Initially discrete supercells are forecast
   to develop over parts of MN and perhaps northern IA by late Thursday
   afternoon. These supercells should pose a threat for very large hail
   given the favorable thermodynamic and kinematic environment. Any
   convection that can remain at least semi-discrete may also pose a
   threat for a few tornadoes early Thursday evening as low-level shear
   increases in tandem with a strengthening southerly low-level jet.

   Eventually, one or more small clusters may develop and pose more of
   a damaging wind threat with eastward extent into Wisconsin Thursday
   evening/night. Given increased confidence in supercell development
   late Thursday afternoon, have increased severe hail probabilities
   and included a corresponding Enhanced Risk across parts of
   southeastern MN, northern IA, and western WI. The southern extent of
   any appreciable severe risk will probably be limited by the strength
   of the cap and warm low/mid-level temperatures with southward extent
   in IA and eastern NE.

   ...Mid Mississippi Valley into the Lower Ohio Valley and
   Carolinas...
   A convectively augmented MCV is forecast to be in place somewhere in
   the vicinity of northern OK and southern KS at the start of the
   period Thursday morning. Most guidance suggests that thunderstorms
   will redevelop and strengthen by late Thursday morning or early
   afternoon across southern MO and vicinity as the MCV progresses
   eastward. A narrow corridor of moderate to strong instability should
   be in place along/south of a front by Thursday afternoon. A favored
   corridor for severe hail and damaging winds will probably exist
   along/south of this front as thunderstorms develop along the length
   of the boundary through Thursday evening, with adequate shear for
   both multicell clusters and perhaps a couple of supercells. Enhanced
   low-level and deep-layer shear should also be present with the MCV
   circulation, which may locally enhance the threat for a few
   tornadoes from parts of southern MO into KY. Farther east into the
   Carolinas, additional clusters of thunderstorms should also develop
   through the afternoon and pose a threat for both severe hail and
   damaging winds as they spread eastward to the coast through Thursday
   evening.

   ..Gleason.. 05/18/2022

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

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