196  
ACUS48 KWNS 200913  
SWOD48  
SPC AC 200912  
 
DAY 4-8 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0312 AM CST MON FEB 20 2017  
 
VALID 231200Z - 281200Z  
   
..DISCUSSION
 
 
MEDIUM-RANGE DETERMINISTIC MODELS CONTINUE TO SHOW GOOD RUN-TO-RUN  
CONSISTENCY IN THEIR DEPICTION OF A POWERFUL SPEED MAX EJECTING INTO  
THE GREAT PLAINS ON THURSDAY (DAY 4) AND SUBSEQUENTLY MOVING  
DOWNSTREAM INTO THE OH VALLEY AND SOUTHERN GREAT LAKES ON FRIDAY  
(DAY 5). A DEEP SURFACE CYCLONE WILL DEVELOP NORTHEASTWARD FROM THE  
CENTRAL GREAT PLAINS TO THE SOUTHWESTERN GREAT LAKES VICINITY ON  
FRIDAY. MODELS SHOW THE ADVECTION OF AN ELEVATED MIXED LAYER AND A  
DRYLINE INTO IL WITH A COLD FRONT EVENTUALLY OVERTAKING THE BOUNDARY  
AND RAPIDLY SURGING EAST-NORTHEAST. THIS OUTLOOK HAS ACCOUNTED FOR  
POSSIBLE DIURNAL WARM-SECTOR DEVELOPMENT NEAR THE SURFACE LOW AND  
THE POSSIBILITY FOR A STRONGLY FORCED SQUALL LINE POSING A RISK FOR  
DAMAGING WINDS. MODELS VARIABILITY INCREASES BY SUNDAY (DAY 7) AND  
MONDAY (DAY 8) ON THE EVOLUTION OF A POSSIBLE DISTURBANCE MOVING  
EASTWARD FROM THE SOUTHERN GREAT PLAINS AND AFFECTING PARTS OF THE  
MS VALLEY DURING THIS TIMEFRAME.  
 
..SMITH.. 02/20/2017  
 
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