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.
Kansas City, MO...Wichita, KS...St. Louis, MO...Overland Park, KS...Kansas City, KS...
SPC AC 261943
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0243 PM CDT Tue Jun 26 2018
Valid 262000Z - 271200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS LATE THIS
AFTERNOON AND EVENING ACROSS PORTIONS OF THE OZARK PLATEAU AND
ADJACENT MISSISSIPPI VALLEY REGION...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SURROUNDING
AREAS EAST-SOUTHEASTWARD ACROSS THE TENNESSEE VALLEY INTO PARTS OF
THE SOUTHERN APPALACHIANS...AS WELL AS ACROSS PARTS OF THE NORTHERN
Severe thunderstorms are likely from eastern Kansas into central
Missouri this afternoon into tonight. Severe storms will also be
possible this afternoon across Kentucky and parts of the western
...20Z Outlook Update...
Considerable adjustments to categorical and probabilistic lines have
been made, generally to attempt to account for stabilizing impacts
of ongoing convection and associated outflow. Moderate to large
boundary layer CAPE has developed in response to daytime heating,
largely focused along and south of a conglomerate outflow boundary,
now roughly extending from eastern portions of the central Plains
through the Missouri Ozarks into the Tennessee Valley and southern
Appalachians. This instability is expected to support a continued
gradual increase in thunderstorm activity, along the southern
periphery of broad troughing within the southern branch of the split
mid-latitude westerlies, where vertical shear appears sufficient to
contribute to organizing clusters with potentially damaging wind
gusts the primary severe hazard.
Across the Upper Midwest, convection continues to gradually increase
near/just ahead of the eastward advancing mid-level closed low.
Mid-level lapse rates appear rather weak, but modest deep layer
shear could still contribute to organization and some potential for
strong wind gusts. Although low-level hodographs and wind fields
are generally weak, there may be some lingering risk for an isolated
relatively brief and weak tornado near an effective warm frontal
zone across parts of northeastern Illinois and adjacent southeastern
For more specific information concerning ongoing or imminent
convective potential, please refer to the latest SPC mesoscale
discussions and watches.
.PREV DISCUSSION... /ISSUED 1130 AM CDT Tue Jun 26 2018/
...KY today to MO/KS through tonight...
A closed midlevel low over IA will continue moving
east-northeastward toward Lake MI by tonight, in conjunction with an
associated/weak surface cyclone. South and southeast of the
midlevel low, multiple thunderstorm complexes are ongoing this
morning from western KY to central MO and central KS. The eastern
complex will likely persist through the afternoon given that it has
a well-developed cold pool and surface heating/destabilization to
its east is already boosting SBCAPE to 3000 J/kg or greater with
minimal convective inhibition. Damaging gusts and isolated large
hail will be the main threats with this convection, plus more
pulse-type storms farther to the east across KY (ahead of the MCS).
An outflow boundary trails westward across southern MO, and clusters
of elevated storms are ongoing atop the cold pool in central MO.
The central MO storms will tend to reinforce the cold pool across
central MO today, but recovery is ongoing across southwest MO where
temperatures are warming into the 80s with dewpoints in the lower
70s F. Continued surface heating/moistening from OK into southeast
KS/southwest MO will drive strong buoyancy (MLCAPE of 3000-4000
J/kg) south and west of the current outflows and the synoptic front
now just south of I-70 in KS. Meanwhile, a cluster of elevated
storms (that formed in a warm advection zone this morning) will have
the potential to become rooted at the surface and generate a cold
pool as it encounters the increasingly unstable environment toward
southeast KS this afternoon. Some combination of growth of the
morning storms or new development later this afternoon along the
synoptic front will pose a threat for large hail and damaging winds.
Low-midlevel vertical shear will be sufficient for some supercell
structures (and possibly isolated very large hail), though storms
should tend to grow upscale into another band/cluster and move
across southeast KS/MO through tonight.
...Northwestern IL and vicinity this afternoon/evening...
Some clouds breaks will allow modest surface heating/destabilization
to the north of the more widespread convection passing south of this
area. A band of ascent attendant to the midlevel low and along the
surface warm front could support a few relatively low-topped
rotating storms, with a tornado or two possible.
...Northern High Plains this afternoon/evening...
A midlevel shortwave trough within a broad zone of cyclonic
mid-upper flow belt will progress eastward across the northern High
Plains and Prairie provinces through tonight. An accompanying cold
front will provide a focus for low-level ascent this
afternoon/evening into western ND and northwestern SD, where
residual dewpoints in the lower 60s F and strong surface heating
will drive moderate buoyancy (MLCAPE of 1500-2000 J/kg. Deep-layer
vertical shear and lapse rates will be sufficient for supercells
capable of producing large hail and damaging winds for a few hours
this afternoon through this evening.
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z