027  
ACUS01 KWNS 151953  
SWODY1  
SPC AC 151952  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0252 PM CDT SUN JUL 15 2018  
 
VALID 152000Z - 161200Z  
 
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF  
THE MID-SOUTH AND WESTERN GREAT BASIN...  
   
..SUMMARY
 
 
ISOLATED STRONG WIND GUSTS MAY OCCUR ACROSS PARTS OF THE MID-SOUTH  
AND WESTERN GREAT BASIN THROUGH THE EVENING.  
   
..20Z UPDATE
 
 
THE ONLY APPRECIABLE CHANGE TO THE OUTLOOK HAS BEEN TO TRIM THE  
WESTERN EXTENT OF 5% WIND PROBABILITIES ACROSS PARTS OF THE  
MID-SOUTH BEHIND AN EASTWARD-MOVING MCV EVIDENT ON VISIBLE SATELLITE  
IMAGERY. ISOLATED STRONG TO DAMAGING WIND GUSTS MAY CONTINUE THROUGH  
THE EARLY EVENING ACROSS THIS REGION GIVEN MODEST ENHANCEMENT TO THE  
LOW AND MID-LEVEL WIND FIELD AND A MOIST/UNSTABLE AIRMASS WHERE  
CONVECTION HAS NOT ALREADY OCCURRED.  
 
NO CHANGES HAVE BEEN MADE TO THE MARGINAL RISK AREA ACROSS PARTS OF  
THE WESTERN GREAT BASIN, WHERE ISOLATED STRONG/GUSTY WINDS MAY OCCUR  
WITH ANY THUNDERSTORM THROUGH LATE THIS EVENING.  
 
ELSEWHERE, VERY ISOLATED INSTANCES OF STRONG WINDS MAY OCCUR WITH  
ONGOING CONVECTION THROUGH PEAK HEATING, BUT GENERALLY WEAK SHEAR  
SHOULD TEND TO LIMIT CONVECTIVE ORGANIZATION.  
 
..GLEASON.. 07/15/2018  
   
PREV DISCUSSION
 
/ISSUED 1129 AM CDT SUN JUL 15 2018/  
   
..MID-SOUTH
 
 
A WEAK/REMNANT MCV WILL CONTINUE TO DRIFT EAST-SOUTHEASTWARD TOWARD  
THE LOWER OHIO RIVER VALLEY TODAY, WITH RELATED ASCENT CONTRIBUTING  
TO THUNDERSTORM DEVELOPMENT WITHIN A MOIST AND UNSTABLE AIR MASS TO  
ITS SOUTH. A CLUSTER OF SEMI-ORGANIZED SOUTHEASTWARD-MOVING STORMS  
IS ONGOING LATE THIS MORNING ACROSS NORTHERN TENNESSEE, WITH  
OUTFLOWS/DIFFERENTIAL HEATING LIKELY TO FOCUS ADDITIONAL  
THUNDERSTORM DEVELOPMENT THIS AFTERNOON MAINLY ACROSS SOUTHEAST  
MISSOURI, NORTHEAST ARKANSAS INTO WESTERN PORTIONS OF KENTUCKY AND  
TENNESSEE. ON THE SOUTHERN FRINGE OF THICKER CLOUD COVER TO THE  
NORTH, DAYTIME HEATING OF A VERY MOIST BOUNDARY LAYER CONSISTING OF  
MIDDLE 70S SURFACE DEW POINTS WILL RESULT IN MLCAPE RANGING  
2000-3000 J/KG IN SPITE OF WEAK MID-LEVEL LAPSE RATES. ISOLATED  
STRONG GUSTS PRODUCING LOCALIZED WIND DAMAGE WILL BE A POSSIBILITY  
THIS AFTERNOON THROUGH EARLY EVENING.  
   
..SOUTHERN OREGON AND NORTHERN PORTIONS OF CALIFORNIA/NEVADA
 
 
A MOIST AIR MASS EXISTS ACROSS THE REGION WITH THE 12Z OBSERVED  
SOUNDING FROM RENO, NV FEATURING 0.97 INCHES OF PRECIPITABLE WATER,  
WHICH IS NEAR THE DAILY MAX FOR OBSERVED CLIMATOLOGICAL VALUES.  
WIDELY SCATTERED THUNDERSTORMS ARE ONGOING EARLY TODAY IN RELATION  
TO A NORTHEASTWARD-MOVING SHORTWAVE TROUGH, WITH AN ADDITIONAL  
MID-LEVEL IMPULSE TO APPROACH THE REGION TONIGHT. WHILE WAVE TIMING  
APPEARS TO BE SUB-OPTIMAL IN RELATION TO PEAK HEATING, SOME  
THUNDERSTORM REDEVELOPMENT SHOULD OCCUR THIS AFTERNOON WITH AID OF  
OROGRAPHIC LIFT/DIFFERENTIAL HEATING. MODEST DEEP-LAYER SHEAR IN  
CONJUNCTION WITH AMPLE HEATING AND A RELATIVELY MOIST AIR MASS COULD  
SUPPORT A FEW LOCALLY SEVERE STORMS WITH DOWNBURSTS AND SMALL HAIL.  
   
..PORTIONS OF COLORADO/WYOMING
 
 
WHILE A FEW STRONGER STORMS COULD OCCUR THIS AFTERNOON, THE OVERALL  
ORGANIZED SEVERE POTENTIAL IS EXPECTED TO REMAIN LIMITED BY  
RELATIVELY WEAK MID-LEVEL LAPSE RATES AS WELL AS WEAK WIND SPEEDS  
(ALBEIT WITH SOME VERTICAL VEERING) THROUGH THE LOW/MIDDLE  
TROPOSPHERE.  
   
..MINNESOTA ARROWHEAD/LAKE SUPERIOR VICINITY
 
 
ALTHOUGH A STRONG STORM COULD OCCUR, THE POTENTIAL FOR SEVERE STORMS  
ACROSS THIS REGION SHOULD REMAIN MARGINAL OR VERY LOCALIZED OWING TO  
LINGERING CLOUD COVER AND MODEST CONVERGENCE ALONG THE ADVANCING  
FRONT. THE OVERALL SEVERE RISK CURRENTLY APPEARS LOW.  
 

 
 
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