365  
ACUS01 KWNS 220601  
SWODY1  
SPC AC 220559  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1259 AM CDT FRI JUN 22 2018  
 
VALID 221200Z - 231200Z  
 
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN CO  
INTO CENTRAL OK...  
 
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF  
THE LOWER MS VALLEY...SOUTHEAST...AND MID-ATLANTIC...  
   
..SUMMARY
 
 
SCATTERED SEVERE STORMS WILL BE POSSIBLE ACROSS PARTS OF THE  
CENTRAL/SOUTHERN PLAINS, SOUTHEAST AND MID-ATLANTIC STATES TODAY.  
   
..SOUTHEAST INTO THE OH VALLEY AND MID-ATLANTIC
 
 
UPPER LOW CURRENTLY MOVING THROUGH THE MIDDLE MS VALLEY IS EXPECTED  
TO GRADUALLY MOVE NORTHEASTWARD THROUGH THE OH VALLEY WHILE  
DEVOLVING INTO AN OPEN WAVE. A SERIES OF VORTICITY MAXIMA WILL  
ROTATE AROUND THIS UPPER LOW, ACCOMPANIED BY ANOMALOUSLY STRONG  
MID-LEVEL FLOW, WHICH IS EXPECTED TO SPREAD ACROSS NORTHERN PORTIONS  
OF THE SOUTHEAST AND INTO THE MID-ATLANTIC.  
 
THUNDERSTORMS WILL LIKELY BE ONGOING AT THE BEGINNING OF THE PERIOD  
AS ONE OF THE LOBES OF VORTICITY MOVES INTO THE LOWER MS VALLEY,  
PROVIDING THE IMPETUS FOR CONVECTION WITHIN THE MOIST AND  
LOW-INHIBITION AIRMASS. DESPITE THE UNFAVORABLE TIMING, THE AIRMASS  
WILL LIKELY BE MODERATELY UNSTABLE WITH TEMPERATURES IN THE LOW 80S  
AND DEWPOINTS IN THE MID 70S HELPING SUPPORT MLCAPE OVER 2000 J/KG.  
AS PREVIOUSLY MENTIONED, SEASONALLY STRONG FLOW ALOFT WILL INCREASE  
BULK SHEAR AND THE POTENTIAL FOR MORE ROBUST, LONGER-LIVED UPDRAFT  
ORGANIZATION. CONSEQUENTLY, THESE EARLY STORMS WILL LIKELY POSE A  
SEVERE THREAT FROM NORTHERN LA/SOUTHERN AR EASTWARD ACROSS CENTRAL  
MS AND AL. WATER-LOADED DOWNBURSTS AND HAIL ARE THE PRIMARY THREATS.  
A TORNADO OR TWO CANNOT BE RULED OUT, PARTICULARLY ON THE WESTERN  
PERIPHERY OF ANY CONVECTIVE LINE WHERE ENHANCED STORM-RELATIVE  
HELICITY FROM ANY SOUTHWESTWARD PROGRESSING STORMS COULD CONTRIBUTE  
TO LOCALLY HIGHER TORNADO THREAT.  
 
VORTICITY MAXIMUM RESPONSIBLE FOR THESE EARLY DAY STORMS WILL  
CONTINUE EASTWARD, LIKELY REACHING THE PIEDMONT AROUND OR JUST AFTER  
PEAK HEATING. ATTENDANT FORCING FOR ASCENT COUPLED WITH AIRMASS  
DESTABILIZATION WILL LIKELY CONTRIBUTE TO INCREASED THUNDERSTORM  
COVERAGE IN THIS REGION INTO THE EVENING. FARTHER NORTH, MORE SUBTLE  
FORCING MAY CONTRIBUTE TO AFTERNOON STORMS IN THE VICINITY OF THE  
WEDGE FRONT. WHILE THE OVERALL BULK SHEAR WILL BE MODEST,  
EASTERLY/SOUTHEASTERLY WINDS NEAR THE BOUNDARY COULD ENHANCED  
LOW-LEVEL SHEAR WHILE ALSO INCREASING VERTICAL VORTICITY ALONG THE  
BOUNDARY ITSELF. AS A RESULT, A SMALL AREA OF RELATIVELY ENHANCED  
TORNADO PROBABILITY EXISTS ACROSS SOUTHEAST VA.  
   
..SOUTHERN/CENTRAL PLAINS
 
 
FAST-MOVING SHORTWAVE TROUGH CURRENTLY ENTERING THE WESTERN GREAT  
BASIN WILL CONTINUE EASTWARD, MOVING THROUGH THE HIGH PLAINS DURING  
THE AFTERNOON AND THROUGH THE PLAINS OVERNIGHT. STRONG LEE  
CYCLOGENESIS IS ANTICIPATED AHEAD OF THIS SYSTEM ACROSS SOUTHEAST CO  
WITH RESULTING SOUTHERLY FLOW ENCOURAGING MOISTURE RETURN INTO THE  
CENTRAL PLAINS/HIGH PLAINS. HIGH 50S DEWPOINTS, POSSIBLY LOW 60S,  
WILL LIKELY ARC INTO SOUTHEAST CO ALONG THE NORTHERN PERIPHERY OF  
THE SURFACE LOW. STEEP MID-LEVEL LAPSE RATES ADVECTED AHEAD OF THE  
APPROACHING SHORTWAVE ATOP THIS AT LEAST MODERATELY MOIST LOW-LEVEL  
AIRMASS WILL RESULT IN MODERATE TO STRONG INSTABILITY DURING THE  
AFTERNOON. ADDITIONALLY, INCREASING MID-LEVEL FLOW ATTENDANT TO THE  
APPROACHING SHORTWAVE TROUGH ATOP EASTERLY/SOUTHEASTERLY RESULTS IN  
STRONGLY SHEARED ENVIRONMENT. 0-6 KM BULK SHEAR OVER 50 KT IS  
LIKELY. ALL OF THESE FACTORS POINT TO THE POTENTIAL FOR  
THUNDERSTORMS CAPABLE OF HAIL OVER 2 INCHES IN DIAMETER AND WIND  
GUSTS OVER 60 KT ACROSS EASTERN CO. TORNADOES ARE ALSO POSSIBLE,  
PARTICULARLY IF STORMS ARE ABLE TO REMAIN DISCRETE.  
 
STRONG COLD POOL GENERATION COUPLED WITH THE STRONG FORCING FOR  
ASCENT AND FAST-MOVING SHORTWAVE TROUGH ALL POINT TO LIKELIHOOD FOR  
QUICK UPSCALE GROWTH INTO WHAT COULD BE A SIGNIFICANT MESOSCALE  
CONVECTIVE SYSTEM. STEEP MID-LEVEL LAPSE RATES DOWNSTREAM INTO OK  
COUPLED WITH A STRONG LOW-LEVEL JET ALSO POINT TO THE POTENTIAL FOR  
A WELL-ORGANIZED SYSTEM CAPABLE OF TRACKING MUCH FARTHER EAST THAN  
WOULD NORMALLY BE EXPECTED GIVEN THE INCREASED CONVECTIVE  
INHIBITION.  
 
..MOSIER/WENDT.. 06/22/2018  
 

 
 
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