449  
ACUS48 KWNS 190836  
SWOD48  
SPC AC 190834  
 
DAY 4-8 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0334 AM CDT TUE MAR 19 2019  
 
VALID 221200Z - 271200Z  
   
..DISCUSSION
 
 
THE LONGWAVE PATTERN WILL REMAIN GENERALLY UNFAVORABLE FOR ANY  
APPRECIABLE SEVERE THREAT THROUGH AT LEAST D4/FRI. AT THIS TIME, A  
SURFACE RIDGE AXIS WILL SHIFT EASTWARD TOWARD THE MISSISSIPPI RIVER  
VALLEY, ALLOWING FOR A MODIFIED MARITIME AIRMASS TO MIGRATE  
NORTHWESTWARD FROM THE WESTERN GULF INTO TEXAS. MEANWHILE,  
STRENGTHENING MID-LEVEL FLOW WILL MIGRATE NORTHEASTWARD ACROSS THE  
HIGH PLAINS ATOP A SHARPENING LEE SURFACE TROUGH/DRYLINE, PROVIDING  
IMPETUS FOR CONVECTIVE DEVELOPMENT ACROSS THE TEXAS PANHANDLE/SOUTH  
PLAINS. MEAGER INSTABILITY SHOULD LIMIT THE EXTENT OF ANY SEVERE  
THREAT DURING THIS TIMEFRAME. THIS DRYLINE SHOULD SHIFT SLIGHTLY  
EASTWARD INTO WESTERN OKLAHOMA/WEST-CENTRAL TEXAS ON D5/SAT AS  
MID-LEVEL FORCING FOR ASCENT LIFTS NORTHWARD AWAY FROM THE DEEPER  
BOUNDARY LAYER MOISTURE.  
 
GUIDANCE SUGGEST THAT A MORE APPRECIABLE SEVERE THREAT SHOULD  
DEVELOP AROUND D6/SUN ACROSS PORTIONS OF THE SOUTHERN PLAINS. BY  
THIS TIME, LOW 60S F DEWPOINTS WILL HAVE DEVELOPED NORTHWARD TO AT  
LEAST THE RED RIVER VALLEY AREA - AND POSSIBLY NORTHWARD THROUGH  
SOUTHERN OKLAHOMA. MEANWHILE, A JET STREAK ON THE SOUTHERN EXTENT  
OF A PROGRESSIVE SHORTWAVE WILL MIGRATE EASTWARD ATOP THE REMAINING  
DRYLINE AND NEARBY WARM SECTOR. WEAK TO MODERATE SURFACE-BASED  
INSTABILITY AND SUPERCELLULAR VERTICAL WIND PROFILES WILL LIKELY  
FAVOR ALL MODES OF SEVERE WEATHER, WITH THE REMAINING UNCERTAINTY  
INVOLVING SPECIFIC POSITIONING OF RELATED SURFACE FEATURES (I.E.,  
DRYLINE POSITION, NORTHWARD EXTENT OF SURFACE-BASED INSTABILITY) AND  
SPECIFIC ORIENTATION OF THE MID-LEVEL JET AND ATTENDANT MID-LEVEL  
WAVE.  
 
BY D7/MON, THIS THREAT SHOULD SHIFT EASTWARD/SOUTHEASTWARD IN TANDEM  
WITH AN EASTWARD-MOVING SURFACE LOW AND A SOUTHWARD MOVING COLD  
FRONT ENTERING THE TENNESSEE VALLEY. IT APPEARS THAT AT LEAST A  
MARGINAL THREAT FOR SEVERE WEATHER WILL EXIST WITHIN THE WARM SECTOR  
ALONG AND AHEAD OF THESE SURFACE FEATURES, THOUGH A FAIR AMOUNT OF  
UNCERTAINTY EXISTS WITH SPECIFIC POSITIONING OF THESE SURFACE  
FEATURES AND UPSTREAM MID-LEVEL WAVE EVOLUTION.  
 
..COOK.. 03/19/2019  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab SPC Page Main Text Page