858  
ACUS01 KWNS 161300  
SWODY1  
SPC AC 161258  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0758 AM CDT TUE JUN 16 2026  
 
VALID 161300Z - 171200Z  
 
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF  
THE MIDWEST...  
   
..SUMMARY  
 
SEVERE THUNDERSTORMS ARE POSSIBLE TODAY AND TONIGHT ACROSS MULTIPLE  
PARTS OF THE MIDWEST, AS WELL AS ON A MORE ISOLATED BASIS ACROSS THE  
GULF COAST, SOUTH-CENTRAL PLAINS AND NORTHERN PLAINS.  
   
..MIDWEST/GREAT LAKES  
 
A LOW AMPLITUDE SHORTWAVE TROUGH WILL AMPLIFY AND SPREAD  
EAST-SOUTHEASTWARD OVER THE GREAT LAKES TODAY. WHILE OVERALL  
MOISTURE CONTENT WILL REMAIN MODEST, STEADY LOW-LEVEL MOISTENING IS  
EXPECTED AHEAD OF A SURFACE LOW/COLD FRONT, AND SOUTH OF A  
NORTH/NORTHEASTWARD-SHIFTING WARM FRONT. THIS MOISTENING AND  
INSOLATION BENEATH A DEVELOPING MID-LEVEL DRY SLOT SHOULD SUPPORT A  
CORRIDOR OF MODEST DESTABILIZATION AS THE MID-LEVEL COLD POOL  
(INCLUDING 500 MB TEMPERATURES AROUND -18 TO -20C) OVERSPREADS THE  
REGION THIS AFTERNOON. THIS ENVIRONMENT SHOULD BECOME SUFFICIENT FOR  
A DEVELOPING BROKEN BAND OF STRONG/SEVERE LOW-TOPPED STORMS  
INCLUDING SUPERCELLS, POSING A RISK FOR SEVERE HAIL/DAMAGING WINDS  
AND POSSIBLY A COUPLE OF TORNADOES FROM MID-AFTERNOON THROUGH EARLY  
EVENING.  
   
..IOWA/UPPER MIDWEST LATE TONIGHT  
 
A CATEGORICAL SLIGHT RISK HAS BEEN INTRODUCED FOR WHAT SHOULD BE A  
STEADILY INCREASING LATE-NIGHT/PRE-DAWN POTENTIAL FOR LARGE HAIL, AT  
LEAST ON ISOLATED BASIS. THIS POTENTIAL SHOULD TEND TO FOCUS ACROSS  
PARTS OF CENTRAL/EASTERN IOWA. EXACT DETAILS OF TIMING/SPATIAL  
EXTENT OF CAP EROSION ARE A BIT UNCERTAIN, BUT WILL DEFER TO A  
SIGNIFICANTLY STRENGTHENING SOUTHWESTERLY LOW-LEVEL JET AND  
EAST/SOUTHEASTWARD-ADVECTING ELEVATED MIXED LAYER AND AMPLE  
SOURCE-REGION ELEVATED BUOYANCY REGARDING CONCERN FOR LARGE HAIL.  
THIS WILL BE AS ROBUST WARM/MOIST ADVECTION DEVELOPS AND INITIAL  
HEIGHT FALLS ARRIVE INTO THE REGION EARLY WEDNESDAY WITH INCREASING  
ELEVATED CONVECTION PROBABLE.  
   
..SOUTH-CENTRAL PLAINS  
 
NEAR/AHEAD OF THE STALLING FRONT, BOUNDARY-LAYER MOISTENING MAY  
SUPPORT CAPE ON THE ORDER OF 1000-2000 J/KG ACROSS PARTS OF SOUTHERN  
KANSAS INTO SOUTHWESTERN MISSOURI, WHERE MID-LEVEL INHIBITION MAY  
REMAIN WEAK ENOUGH THROUGH LATE AFTERNOON/EARLY EVENING TO ALLOW FOR  
ISOLATED/WIDELY SCATTERED THUNDERSTORM DEVELOPMENT. SUFFICIENT  
VERTICAL SHEAR COULD SUPPORT SUPERCELL DEVELOPMENT. ADDITIONAL  
SEVERE STORM DEVELOPMENT, AT LEAST ON AN ISOLATED BASIS, IS  
PLAUSIBLE FARTHER WEST-SOUTHWEST LATER IN THE AFTERNOON/EARLY  
EVENING ACROSS NORTHERN OKLAHOMA/SOUTHERN KANSAS INTO THE TEXAS  
PANHANDLE.  
   
..NORTHERN GREAT PLAINS INTO MIDWEST  
 
MODELS SUGGEST THAT A CORRIDOR OF FAIRLY DEEP BOUNDARY-LAYER MIXING  
WILL PRECEDE THE VIGOROUS SHORT WAVE TROUGH DIGGING ACROSS AND  
EAST-SOUTHEAST OF THE CANADIAN/NORTHERN U.S. ROCKIES. ASSOCIATED  
MID-LEVEL FORCING FOR ASCENT WILL CONTRIBUTE TO SUFFICIENT  
DESTABILIZATION TO SUPPORT SCATTERED THUNDERSTORM DEVELOPMENT WITH  
POTENTIAL TO PRODUCE SOME HAIL AND SCATTERED STRONG TO SEVERE  
SURFACE GUSTS LATE THIS AFTERNOON INTO EVENING.  
   
..DELMARVA/COASTAL MID-ATLANTIC  
 
SOME STRONG/LOCALLY SEVERE THUNDERSTORMS COULD OCCUR TONIGHT AS  
CONVECTION DEVELOP NEAR/NORTH OF A NEAR-COASTAL/OFFSHORE SURFACE LOW  
AND NORTHWARD-ADVANCING WARM FRONT. STORMS WILL TEND TO BE ELEVATED  
INLAND, BUT MODEST BUOYANCY AND STRONG UNIDIRECTIONAL SHEAR THROUGH  
THE CLOUD-BEARING LAYER COULD YIELD SOME HAIL AND/OR GUSTY WINDS.  
   
..GULF COAST  
 
STRENGTHENING WESTERLY FLOW, INCLUDING 20-40 KT IN THE 850-500 MB  
LAYER, IS ANTICIPATED REGIONALLY COINCIDENT WITH A MOIST BOUNDARY  
LAYER. AS DIURNAL HEATING/DESTABILIZATION OCCURS, THIS MAY SUPPORT  
MODESTLY ORGANIZING CONVECTION, PERHAPS TRANSIENT SUPERCELL  
STRUCTURES, POSING A RISK FOR DAMAGING WIND GUSTS AND PERHAPS A  
BRIEF TORNADO OR TWO.  
 
..GUYER/BROYLES.. 06/16/2026  
 
 
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