928  
ACUS02 KWNS 260601  
SWODY2  
SPC AC 260600  
 
DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0100 AM CDT FRI MAY 26 2017  
 
VALID 271200Z - 281200Z  
 
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF  
THE SOUTHERN AND CENTRAL PLAINS EAST-NORTHEASTWARD INTO THE MID  
MISSISSIPPI VALLEY...  
 
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OUTSIDE OF THE  
ENHANCED RISK AREA ACROSS PARTS OF THE SOUTHERN AND CENTRAL PLAINS  
EAST-NORTHEASTWARD INTO THE MID MISSISSIPPI VALLEY...CENTRAL  
APPALACHIAN MOUNTAINS AND MID-ATLANTIC...  
 
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OUTSIDE OF THE  
SLIGHT RISK AREA FROM PARTS OF THE OUTSIDE OF THE ENHANCED RISK AREA  
ACROSS PARTS OF THE SOUTHERN AND CENTRAL PLAINS EAST-NORTHEASTWARD  
INTO THE MID MISSISSIPPI VALLEY...CENTRAL APPALACHIAN MOUNTAINS AND  
MID-ATLANTIC...  
   
..SUMMARY
 
 
WIDESPREAD SEVERE THUNDERSTORMS WITH WIND DAMAGE, LARGE HAIL AND A  
FEW TORNADOES ARE EXPECTED SATURDAY AND SATURDAY NIGHT FROM PARTS OF  
THE SOUTHERN AND CENTRAL PLAINS EAST-NORTHEASTWARD INTO THE MID  
MISSISSIPPI VALLEY AND MID-ATLANTIC.  
   
..SOUTHERN AND CENTRAL PLAINS/MID MISSISSIPPI VALLEY
 
 
AN UPPER-LEVEL TROUGH IS FORECAST TO MOVE EAST-SOUTHEASTWARD ACROSS  
THE NORTHERN PLAINS AND CENTRAL ROCKIES ON SATURDAY AS  
WEST-SOUTHWESTERLY FLOW REMAINS LOCATED ACROSS THE SOUTHERN AND  
CENTRAL PLAINS EAST-NORTHEASTWARD INTO THE MID MISSISSIPPI VALLEY.  
AT THE SURFACE, A COLD FRONT IS FORECAST TO ADVANCE SOUTHEASTWARD  
ACROSS THE CENTRAL PLAINS AND SOUTHERN HIGH PLAINS. A VERY MOIST AND  
UNSTABLE AIRMASS SHOULD BE IN PLACE SATURDAY FROM EASTERN PARTS OF  
THE SOUTHERN PLAINS NORTHEASTWARD INTO THE MID MISSISSIPPI VALLEY.  
SURFACE DEWPOINTS ARE FORECAST TO BE IN THE LOWER TO MID 70S F  
ACROSS MUCH OF THIS CORRIDOR CONTRIBUTING TO MODERATE TO STRONG  
INSTABILITY BY AFTERNOON. DETERMINISTIC AND HIGH-RES SOLUTIONS  
SUGGEST THAT A COMPLEX OF THUNDERSTORMS WILL FIRST DEVELOP ACROSS  
THE CENTRAL PLAINS AROUND MIDDAY WITH THIS COMPLEX GROWING IN SIZE  
AND MOVING EAST-SOUTHEASTWARD INTO THE MID MISSISSIPPI VALLEY DURING  
THE AFTERNOON. THE DEVELOPMENT OF A LINEAR MCS WILL BE POSSIBLE BY  
EARLY EVENING ACROSS THE ENHANCED RISK AREA.  
 
GFS FORECAST SOUNDINGS ON SATURDAY ALONG THE NORTHERN EDGE OF THE  
STRONGEST INSTABILITY FROM SOUTHEAST KANSAS INTO SOUTHERN MISSOURI  
SHOW A CAPPING INVERSION IN PLACE FOR MUCH OF THE DAY. THIS CAP IS  
FORECAST TO WEAKEN BY LATE AFTERNOON. FORECAST SOUNDINGS ALSO SHOW  
AN IMPRESSIVE THERMODYNAMIC ENVIRONMENT WITH MLCAPE VALUES AROUND  
4000 J/KG ACROSS MUCH OF NORTHEAST TEXAS, EASTERN OKLAHOMA AND  
SOUTHERN MISSOURI. IN ADDITION, 40 TO 50 KT OF 0-6 KM SHEAR IS  
FORECAST ALONG THIS CORRIDOR SUGGESTING THUNDERSTORMS WILL HAVE NO  
PROBLEM ORGANIZING. THE MAIN QUESTION IS WHAT MODE WILL BE FAVORED.  
SOME HIGH-RES SOLUTIONS SHOW TWO BOWING LINE SEGMENTS MOVING  
EAST-SOUTHEASTWARD ACROSS THE ENHANCED RISK AREA. THIS WOULD BE MORE  
FAVORABLE FOR A WIND-DAMAGE THREAT. IF THE STORMS CAN FORM INTO  
CLUSTERS INSTEAD OF LINES, THEN SUPERCELLS WITH LARGE HAIL AND  
ISOLATED WIND DAMAGE WILL BE FAVORED. HAILSTONES OF GREATER THAN 2  
INCHES IN DIAMETER WILL BE POSSIBLE WITH SUPERCELLS MAINLY FROM  
SOUTHWEST MISSOURI INTO NORTHEAST TEXAS. A TORNADO THREAT SHOULD  
OCCUR ACROSS PARTS OF THE REGION ESPECIALLY AS LOW-LEVEL FLOW  
STRENGTHENS ACROSS THE REGION. THE SEVERE THREAT SHOULD BE MORE  
ISOLATED WITH SOUTHWESTWARD EXTENT ACROSS PARTS OF NORTHEAST AND  
CENTRAL TEXAS.  
   
..OHIO AND TENNESSEE VALLEYS/MID-ATLANTIC
 
 
AN UPPER-LEVEL RIDGE IS FORECAST TO MOVE EASTWARD ACROSS THE OHIO  
AND TENNESSEE VALLEYS ON SATURDAY AS A WARM FRONT ADVANCES  
NORTHEASTWARD INTO THE SOUTHERN GREAT LAKES AND UPPER OHIO VALLEY.  
THUNDERSTORMS ARE FORECAST TO DEVELOP ALONG THE WARM FRONT WITH THIS  
CONVECTION MOVING EAST-SOUTHEASTWARD ACROSS THE REGION DURING THE  
AFTERNOON. FORECAST SOUNDINGS AT 21Z ON SATURDAY ALONG AND TO THE  
SOUTH OF THE WARM FRONT IN EASTERN KENTUCKY, SOUTHERN OHIO AND WEST  
VIRGINIA SHOW MODERATE INSTABILITY WITH MLCAPE VALUES OF 1000 TO  
2000 J/KG, 0-6 KM SHEAR VALUES AROUND 30 KTS AND STEEP LOW-LEVEL  
LAPSE RATES. THIS ENVIRONMENT SHOULD SUPPORT A WIND-DAMAGE THREAT  
WITH MULTICELL LINE SEGMENTS THAT CAN BECOME ORGANIZED. HAIL WILL  
ALSO BE POSSIBLE WITH THE STRONGER UPDRAFTS.  
 
..BROYLES.. 05/26/2017  
 

 
 
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