008  
FXUS66 KSTO 172125  
AFDSTO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SACRAMENTO CA  
225 PM PDT WED OCT 17 2018  
 
   
SYNOPSIS
 
 
WARM AND DRY THIS WEEK. CHANCE OF PRECIPITATION BY THE MIDDLE OF  
NEXT WEEK.  
 

 
   
DISCUSSION
 
 
EASTERN PACIFIC HIGH PRESSURE SYSTEM WILL GRADUALLY SHIFT EAST  
OVER NOCAL THROUGH THE WEEK. THIS WILL KEEP DRY CONDITIONS AND  
WARM DAYTIME TEMPERATURES OVER THE AREA. HIGH TEMPERATURES IN  
80'S FOR VALLEY LOCATIONS WILL BE 5 TO 10 DEGREES ABOVE NORMAL,  
OVERNIGHT LOWS WILL COOL TO NEAR 50 WITH UPPER 40'S AT OUTLYING  
SPOTS.  
 
UPPER HIGH OVER NORCAL SETTING UP ABOVE LOW PRESSURE OVER SOCAL  
WILL CAUSE DOWNSLOPE EAST WINDS OVER THE SIERRA FRIDAY AND  
SATURDAY. A FEW GUSTS TO 25 MPH WILL BE POSSIBLE.  
 

 
 
.EXTENDED DISCUSSION (SUNDAY THROUGH WEDNESDAY)  
 
WEAK UPPER LOW FORECAST TO PUSH ACROSS CALIFORNIA ON SUNDAY  
BRINGING MINIMAL IMPACTS TO NORCAL WEATHER. ANY PRECIPITATION  
ASSOCIATED WITH THIS LOW SHOULD REMAIN SOUTH OF THE FORECAST AREA  
AND EVEN WITH A SLIGHT COOLING, DAYTIME HIGHS ARE EXPECTED TO  
REMAIN SLIGHTLY ABOVE NORMAL. UPPER LEVEL REX BLOCK PATTERN SHIFTS  
INTO THE GREAT BASIN ON MONDAY BRINGING SLIGHTLY COOLER  
TEMPERATURES BUT MORE IMPORTANTLY, THE START OF A TRANSITION TO A  
COOLER AND POSSIBLY WETTER WEATHER PATTERN. MODELS ARE IN FAIRLY  
GOOD AGREEMENT IN PUSHING A SHORTWAVE TROUGH INTO THE PACIFIC  
NORTHWEST AND NORCAL ON TUESDAY. MODELS DO DIFFER A BIT ON DEPTH  
OF THIS SYSTEM BUT CURRENTLY KEEP PRECIPITATION THREAT OVER THE  
NORTHERN PORTIONS OF THE CWA. BACKED OFF SOMEWHAT ON EXPANSE OF  
PRECIPITATION CHANCES USING LATEST NBM AS A GUIDE. EVEN WITH THE  
COOLING EFFECT AND CLOUD COVER, CURRENT FORECASTS STILL KEEP  
DAYTIME HIGHS TUESDAY SLIGHTLY ABOVE NORMAL. ANOTHER SHORTWAVE  
TROUGH IS FORECAST TO MOVE INTO THE PACIFIC NORTHWEST NEXT  
WEDNESDAY FOR ANOTHER DEGREE OR TWO OF COOLING BUT THIS STILL  
LOOKS TO BE A FAR NORTHERN CALIFORNIA PRECIPITATION PRODUCER.  
 

 
   
AVIATION
 
 
VFR SKC CONDITIONS THROUGH THU. WINDS GENERALLY VRB05KT OR NEARLY  
CALM AT TAF SITES. LIGHT DOWNSLOPE (NE-E) WINDS OVER W SLOPE  
SIERRA.  
 

 
   
STO WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
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