670  
ACUS03 KWNS 181908  
SWODY3  
SPC AC 181907  
 
DAY 3 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0207 PM CDT SUN OCT 18 2026  
 
VALID 201200Z - 211200Z  
   
..NO SEVERE THUNDERSTORM AREAS FORECAST  
 
   
..SUMMARY  
 
NO SEVERE THUNDERSTORMS ARE EXPECTED ON TUESDAY.  
   
..SYNOPSIS  
 
A LARGE UPPER TROUGH IS FORECAST TO AMPLIFY JUST OFF THE CA COAST,  
WITH INCREASING SOUTH/SOUTHWEST WINDS ALOFT, AS WELL AS COOLING  
ALOFT NEAR THE COAST OVERNIGHT. TO THE EAST, MINOR HEIGHT RISES WILL  
OCCUR OVER THE PLAINS, WHILE AN UPPER LOW MEANDERS OFF THE MID  
ATLANTIC COAST.  
 
AT THE SURFACE, HIGH PRESSURE OVER THE UPPER GREAT LAKES AND ONTARIO  
WILL SHIFT EASTWARD, THOUGH THE SURFACE RIDGE WILL REMAIN ENTRENCHED  
INTO THE SOUTHERN PLAINS. THIS WILL MAINTAIN STABLE CONDITIONS OVER  
THE CENTRAL AND EASTERN STATES.  
 
GENERAL THUNDERSTORM CHANCES WILL BE LIMITED TO PARTS OF THE  
SOUTHWESTERN STATES IN RELATION TO THE UPPER TROUGH. VEERING WINDS  
WITH HEIGHT AND MODERATE DEEP-LAYER SHEAR WILL DEVELOP OVER AZ AND  
NM AS THE UPPER TROUGH AMPLIFIED. HOWEVER, FORECAST SOUNDINGS SHOW A  
SUBSIDENCE INVERSION ABOVE 500 MB DURING THE DAY, WHICH WILL LIMIT  
STORM INTENSITY. OVERNIGHT, ELEVATED INSTABILITY MAY INCREASE AS  
COOLING ALOFT OCCURS, WITH ISOLATED STORMS STILL POSSIBLE. POTENTIAL  
SHOULD GENERALLY INCREASE INTO WEDNESDAY/D4 AS THE UPPER TROUGH  
STRENGTHENS.  
 
..JEWELL.. 10/18/2026  
 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab SPC Page
Main Text Page