475  
ACUS01 KWNS 071245  
SWODY1  
SPC AC 071244  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0644 AM CST TUE NOV 07 2017  
 
VALID 071300Z - 081200Z  
   
..NO SEVERE THUNDERSTORM AREAS FORECAST
 
 
   
..SUMMARY
 
 
THUNDERSTORMS ARE POSSIBLE FROM THE COASTAL CAROLINAS/DELMARVA TO  
PARTS OF EAST TEXAS TODAY.  
   
..SYNOPSIS
 
 
IN MID/UPPER LEVELS, A BROAD BELT OF ZONAL FLOW WILL COVER MOST OF  
THE CENTRAL AND EASTERN U.S., DOWNSTREAM FROM A POSITIVELY TILTED  
SHORTWAVE TROUGH NOW LOCATED OVER THE NORTHERN PLAINS, NORTHERN  
ROCKIES AND GREAT BASIN. THAT TROUGH IS FORECAST TO ELONGATE AND  
SHIFT EAST-SOUTHEASTWARD, AND BY 00Z, SHOULD REACH SOUTHERN LAKE  
MICHIGAN, NORTHERN IA, NORTHERN NE, SOUTHERN WY, TO AN ANCHORING  
VORTICITY LOBE OVER EASTERN UT. THE TROUGH WILL CONTINUE TO STRETCH  
OVERNIGHT, EXTENDING FROM THE MID-ATLANTIC ACROSS MUCH OF THE CORN  
BELT TO THE MAIN VORTICITY MAX OVER CO BY 12Z. THOUGH LACKING  
SUBSTANTIAL EMBEDDED SHORTWAVES, THE DOWNSTREAM/ZONAL PATTERN ACROSS  
THE SOUTHEAST WILL BE CHARACTERIZED BY HEIGHT FALLS.  
 
AT THE SURFACE, A WEAK LOW WAS ANALYZED AT 11Z OVER EASTERN MIDDLE  
TN, WITH COLD FRONT SOUTHWESTWARD ACROSS NORTHERN MS, NORTHERN LA,  
AND CENTRAL/SOUTHWEST TX. THE LOW SHOULD MIGRATE ACROSS THE  
MOUNTAINS AND NC, ALONG A SLOWER-MOVING TO STATIONARY SEGMENT OF THE  
FRONT TO ITS EAST. MEANWHILE, BY 00Z, THE COLD FRONT SHOULD REACH  
NORTHERN GA, CENTRAL MS, AND SOUTHEAST/SOUTH-CENTRAL TX. BY 12Z,  
THE FRONT SHOULD BE LOCATED FROM SOUTHERN SC ACROSS SOUTHERN PARTS  
OF MS/AL TO THE NORTHWESTERN GULF, AND DEEP SOUTH TEXAS.  
   
..NORTHERN GA, SOUTHEASTERN TN, WESTERN/CENTRAL CAROLINAS
 
 
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE POSSIBLE TODAY NEAR  
THE SURFACE COLD FRONT AS THE BOUNDARY CROSSES THE REGION.  
DESTABILIZATION FOR SURFACE-BASED PARCELS BECOMES MORE UNCERTAIN  
WITH NORTHWARD EXTENT ACROSS THE SOUTHERN APPALACHIANS REGION, IN  
THE WAKE OF ONGOING NON-SEVERE THUNDERSTORMS CROSSING THE REGION.  
TO THEIR SOUTH, A COMBINATION OF DIURNAL/DIABATIC SURFACE HEATING  
AND DEW POINTS IN THE 60S F MAY YIELD A SOUTHWEST-NORTHEAST PLUME OF  
MLCAPE REACHING 500-1000 J/KG FROM MIDDAY THROUGH LATE AFTERNOON.  
WEAK LAPSE RATES/INSTABILITY ALOFT, AND VEERED PREFRONTAL WINDS IN  
THE BOUNDARY LAYER, CAST DOUBTS ON STRENGTH OF LIFT NEEDED TO  
SUSTAIN CONVECTION, AND THUS ON CONVECTIVE COVERAGE/STRENGTH, EVEN  
THOUGH FORECAST SOUNDINGS SUGGEST 40-50 KT EFFECTIVE-SHEAR  
MAGNITUDES ARE POSSIBLE. ISOLATED DAMAGING GUSTS APPROACHING SEVERE  
LIMITS, OR SMALL HAIL, CANNOT BE DEFINITIVELY RULED OUT FROM A  
THUNDERSTORM OR TWO IN THIS ENVIRONMENT; HOWEVER, THE POTENTIAL  
STILL APPEARS TOO CONDITIONAL TO WARRANT CATEGORICAL-LEVEL  
PROBABILITIES AT THIS TIME.  
 
..EDWARDS/MOSIER.. 11/07/2017  
 

 
 
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