134  
FXUS65 KREV 142217  
AFDREV  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE RENO NV  
217 PM PST THU DEC 14 2017  
   
SYNOPSIS
 
 
TEMPERATURE INVERSIONS AND REDUCED AIR QUALITY IN URBAN VALLEYS  
CONTINUE THROUGH FRIDAY AFTERNOON, WITH A WEAK SYSTEM FRIDAY  
NIGHT INCREASING SURFACE WINDS AND BRINGING IMPROVED AIR QUALITY  
FOR THE WEEKEND. INVERSIONS ARE LIKELY TO STRENGTHEN AGAIN EARLY  
NEXT WEEK BEFORE A COLD FRONT MOVES THROUGH FOR THE MIDDLE OF NEXT  
WEEK AND BREAKS THE INVERSIONS.  
 

 
   
SHORT TERM
 
 
BEEFED UP WINDS IN SIERRA SATURDAY INTO SUNDAY MORNING, OTHERWISE  
LITTLE CHANGE TO THE SHORT TERM FORECAST.  
 
TEMPERATURE INVERSIONS CONTINUE TODAY AND ARE EXPECTED TO WEAKEN  
FRIDAY NIGHT AND SATURDAY AS A FAST-MOVING SHORTWAVE MOVES THROUGH  
NORTHEAST CALIFORNIA AND WESTERN NEVADA. BETTER MIXING AND  
INCREASING NORTHERLY LOW LEVEL WINDS SHOULD BE ENOUGH TO ALLOW FOR  
INCREASING AIR QUALITY GOING INTO THE WEEKEND.  
 
THIS SYSTEM HAS VERY LITTLE MOISTURE ASSOCIATED WITH IT AND IS  
FORECAST TO BEGIN SHEARING/SPLITTING AS IT MOVES THROUGH CENTRAL  
CALIFORNIA. THE BEST PRECIPITATION CHANCES IN EARLY MORNING  
SIMULATIONS ARE IN FAR NORTHWEST AND NORTH-CENTRAL NEVADA BEHIND  
THE COLD FRONT; HOWEVER, SOME LATE MORNING SIMULATIONS INDICATE A  
NARROW PRECIPITATION BAND MOVING DOWN TO BETWEEN PYRAMID LAKE AND  
I-80 IN FAR WESTERN NEVADA. DRY AIR AHEAD OF THE COLD FRONT WILL  
HELP SNOW LEVELS DROP QUICKLY TO VALLEY FLOORS, BUT WITH THE LACK  
OF MOISTURE (LESS THAN 0.10" OF PRECIPITATION IN MOST  
SIMULATIONS), LITTLE (LESS THAN 1/2") TO NO SNOW ACCUMULATION IS  
EXPECTED FOR MOST AREAS. STILL, BE ALERT IF TRAVELING EARLY  
SATURDAY AS EVEN LIGHT SNOW SHOWERS OVERNIGHT COULD BRING A THIN  
LAYER OF PATCHY ICE AS TEMPERATURES FALL TO NEAR OR BELOW FREEZING  
SATURDAY MORNING.  
 
ONE OTHER ITEM OF NOTE WILL BE STRENGTHENING EASTERLY WINDS OVER  
SIERRA RIDGES FOR THE WEEKEND AS HIGH PRESSURE REBUILDS INTO THE  
GREAT BASIN. THE DEPTH OF THE COLDER AIR INTRUSION AND STRENGTH OF  
WINDS ALOFT SHOULD BE SUFFICIENT TO BRING INCREASED WINDS ON LAKE  
TAHOE BY SATURDAY AFTERNOON, LIKELY LASTING INTO SUNDAY MORNING.  
THE WINDS ARE LIKELY TO CAUSE ISSUES FOR SMALL CRAFT ON THE LAKE,  
ESPECIALLY FOR MID-LAKE AND WESTERN SHORES WHERE WAVES WILL BE  
HIGHEST. -ZACH/SNYDER  
   
LONG TERM...MONDAY ONWARD
 
 
HIGH PRESSURE RETURNS FOR EARLY NEXT WEEK RESULTING IN POOR MIXING  
AND VENTILATION AGAIN FOR MONDAY AND TUESDAY. HAZE MAY ONCE AGAIN  
FORM MAINLY NEAR POPULATION CENTERS AS WELL.  
 
SIMULATIONS CONTINUE TO SHOW A STRONG COLD FRONT MOVING SOUTHWARD  
THROUGH THE AREA WEDNESDAY WITH SOME MUCH COLDER AIR SPREADING INTO  
THE SIERRA AND WESTERN NEVADA. LOW CHANCES FOR SHOWERS REMAIN FOR  
WEDNESDAY ALONG THIS FRONT. THE STORM DOESN'T HAVE A SIGNIFICANT  
MOISTURE TAP, BUT IT WILL REQUIRE MONITORING SINCE IT WILL BE SO  
COLD. THE VERY COLD NATURE OF THE STORM MAY RESULT IN SNOW EVEN DOWN  
TO VALLEY FLOORS. THE AIR BEHIND THIS FRONT WILL BE SOME OF THE  
COLDEST WE HAVE SEEN SO FAR AND IT COULD LINGER INTO THE WEEKEND  
RIGHT AHEAD OF CHRISTMAS. HOHMANN/EDAN  
 

 
   
AVIATION
 
 
MAINLY VFR WITH LIGHT WINDS (LESS THAN 8-10 KTS) FOR VALLEYS THROUGH  
FRIDAY MORNING.  
 
VALLEY INVERSIONS WILL REMAIN STRONG THROUGH FRIDAY, RESULTING IN  
SLANTWISE VISIBILITY CONCERNS FOR LOWER VALLEYS, ESPECIALLY IN THE  
RENO/SPARKS, CARSON CITY, AND MINDEN AREAS. INCREASED NORTHERLY  
WINDS FRIDAY NIGHT AND SATURDAY MAY ALLOW SOME OF THE HAZE TO  
CLEAR OUT, AT LEAST FOR A DAY OR TWO. -EDAN/HOHMANN  
 

 
 
   
REV WATCHES/WARNINGS/ADVISORIES
 
 
NV...NONE.  
CA...NONE.  

 
 

 
 
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...  
HTTP://WEATHER.GOV/RENO  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab NV Page
The Nexlab CA Page Main Text Page