851  
ACUS02 KWNS 101651  
SWODY2  
SPC AC 101650  
 
DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1050 AM CST FRI NOV 10 2017  
 
VALID 111200Z - 121200Z  
   
..NO THUNDERSTORM AREAS FORECAST
 
 
   
..SUMMARY
 
 
THE RISK OF SEVERE THUNDERSTORMS APPEARS NEGLIGIBLE ACROSS THE U.S.,  
SATURDAY THROUGH SATURDAY NIGHT.  
   
..DISCUSSION
 
 
WITHIN ONE BRANCH OF SPLIT WESTERLIES, MODELS CONTINUE TO INDICATE  
THAT A SIGNIFICANT DIGGING SHORT WAVE IMPULSE WILL CONTRIBUTE TO  
LARGER SCALE MID/UPPER TROUGH AMPLIFICATION ACROSS THE NORTHEASTERN  
PACIFIC DURING THIS PERIOD. DOWNSTREAM, RIDGING MAY BEGIN TO BUILD  
ACROSS PARTS OF THE GREAT BASIN AND ROCKIES, BUT FLOW EASTWARD INTO  
THE WESTERN ATLANTIC APPEARS LIKELY TO REMAIN GENERALLY ZONAL, WITH  
THE DEAMPLIFYING REMNANTS OF A SHORT WAVE PERTURBATION (CURRENTLY  
PROGRESSING INTO THE PACIFIC NORTHWEST) EMERGING FROM THE  
INTERMOUNTAIN WEST, BEFORE GRADUALLY DIGGING ACROSS THE NORTH  
CENTRAL PLAINS AND MIDDLE/LOWER MISSOURI VALLEY REGION. IN RESPONSE  
TO THESE DEVELOPMENTS, THE CENTER OF EXPANSIVE COLD SURFACE RIDGING  
(CURRENTLY ENCOMPASSING MUCH OF THE CENTRAL AND EASTERN U.S.)  
APPEARS LIKELY TO BEGIN TO WEAKEN WHILE SHIFTING EAST OF THE LOWER  
GREAT LAKES, UPPER OHIO VALLEY, AND CENTRAL APPALACHIANS REGION INTO  
AREAS NEAR/EAST OF THE NORTH ATLANTIC SEABOARD.  
   
..FLORIDA
 
 
IN RESPONSE TO THE EXPANSIVE COLD SURFACE RIDGING, AT LEAST SOME  
CONTINUED LOW-LEVEL DRYING APPEARS PROBABLE ACROSS MUCH OF THE  
FLORIDA PENINSULA AND KEYS INTO SATURDAY. HOWEVER, AS NORTH TO  
NORTHEASTERLY NEAR SURFACE FLOW GRADUALLY TURNS TO  
NORTHEASTERLY/EASTERLY, FORECAST SOUNDINGS SUGGEST THAT SOME  
DEEPENING OF THE RESIDUAL SURFACE-BASED MOIST LAYER IS POSSIBLE,  
BENEATH A RELATIVELY WARM AND CAPPING MID-LEVEL ENVIRONMENT  
ASSOCIATED WITH PREVAILING MID/UPPER SUBTROPICAL RIDGING. ALTHOUGH  
IT APPEARS THAT THIS MAY BE SUFFICIENT TO CONTRIBUTE TO WEAK  
POTENTIAL INSTABILITY, FORCING FOR ASCENT TO OVERCOME INHIBITION  
DURING THIS PERIOD IS NOT READILY EVIDENT, AND THE RISK FOR  
THUNDERSTORM DEVELOPMENT CURRENTLY APPEARS NEGLIGIBLE.  
   
..NORTH CENTRAL PLAINS
 
 
CONSIDERABLE STEEPENING OF LOWER/MID TROPOSPHERIC LAPSE RATES  
APPEARS PROBABLE SATURDAY, PARTICULARLY NEAR LEE SURFACE TROUGHING  
ACROSS THE HIGH PLAINS, IN RESPONSE TO DAYTIME HEATING AND  
DIFFERENTIAL THERMAL ADVECTION. DESPITE THE LACK OF AN APPRECIABLE  
RETURN FLOW OF MOISTURE, IT MAY NOT BE OUT OF THE QUESTION THAT  
THERMODYNAMIC PROFILES BECOME CONDUCIVE TO CONVECTION CAPABLE OF  
GENERATING LIGHTNING, AS THE REMNANT MID-LEVEL WAVE OVERSPREADS THE  
REGION LATE IN THE AFTERNOON AND EARLY EVENING. AT THIS TIME,  
THOUGH, IT APPEARS THAT ANY SUCH WEAK/ SHORT-LIVED THUNDERSTORM  
ACTIVITY WILL BE SPARSE IN COVERAGE. COUPLED WITH OTHER FORECAST  
UNCERTAINTIES, PROBABILITIES FOR THUNDERSTORMS STILL APPEAR TO  
REMAIN LESS THAN 10 PERCENT.  
 
..KERR.. 11/10/2017  
 

 
 
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