179  
FXUS65 KREV 301018 AAA  
AFDREV  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE RENO NV  
318 AM PDT SAT JUL 30 2016  
 
ADDED FIRE WEATHER SECTION AT END  
   
SYNOPSIS
 
 
MOISTURE AND AFTERNOON INSTABILITY WILL KEEP CHANCES OF  
THUNDERSTORMS IN THE FORECAST INTO EARLY NEXT WEEK UNTIL A DRIER  
AND SLIGHTLY COOLER FLOW PATTERN DEVELOPS. HOWEVER, MUCH OF THE  
CONVECTION WILL BE LIMITED SOUTH OF HIGHWAY 50. EXPECT AN  
INCREASE IN AFTERNOON WINDS THIS WEEKEND ACROSS NORTHERN  
CALIFORNIA AND WESTERN NEVADA.  
   
SHORT TERM
 
 
A FEW MODEST CHANGES WERE MADE TO THE EXISTING FORECAST PRIMARILY  
CONCERNING THUNDERSTORM CHANCES AND HAZE FROM NEARBY WILDFIRES.  
THE COVERAGE OF ISOLATED THUNDERSTORMS WAS EXPANDED NORTHWARD  
ALONG THE VIRGINIA RANGE AS SUGGESTED BY HRRR WHICH SHOWS ANOTHER  
ROUND OF LATE AFTERNOON THUNDERSTORMS. THIS IS REASONABLE  
CONSIDERING THAT MOISTURE IS STILL AVAILABLE WITH AMPLE SURFACE  
INSTABILITY FROM AFTERNOON HEATING. KEPT CHANCES EAST OF  
RENO/SPARKS AS AFTERNOON WESTERLIES WILL LIKELY PUSH DEVELOPING  
CONVECTION OVER THE VIRGINIA RANGE. ALSO, ADDED HAZE THROUGH  
TOMORROW MORNING AS AREA WILDFIRES REMAIN ACTIVE EARLY THIS  
MORNING.  
 
OTHERWISE, THE STORY IS THE SAME. EXPECT HAZE FOR MUCH OF THE  
REGION AS SMOKE SEEPS THROUGH VALLEYS AND SETTLES IN VALLEYS/SINKS  
EARLY THIS MORNING. ANOTHER ROUND OF ISOLATED TO SCATTERED  
THUNDERSTORMS ARE ON TAP THIS AFTERNOON AND EVENING AS MOISTURE  
LINGERS; FORECAST PWATS 0.65-0.75" AND CAPE ~500J/KG. THE BEST  
CHANCES WILL BE IN SOUTHERN LYON COUNTY AND WESTERN MINERAL COUNTY  
OVER TERRAIN FEATURES. LOWER CHANCES WILL EXTEND NORTHWARD WITH  
FOCUS FOR CONVECTION OVER TYPICAL CONVERGENCE ZONES ALONG THE PINE  
NUT AND VIRGINIA MOUNTAIN RANGES. SOME CELLS MAY REACH THE  
SOUTHERN PAH RAHS AND OUTFLOW COULD THREATEN FIRE SUPPRESSION  
EFFORTS ON AREA WILDFIRES. GUSTS ARE NOT EXPECTED TO BE  
INORDINATELY STRONG WITH GARDEN VARIETY OUTFLOW 35-40 MPH TODAY;  
A RARE CELL MAY BE CAPABLE OF GUSTS TOWARDS 55 MPH IF IT MOVES OFF  
TERRAIN OVER DRIER VALLEYS. DRIER AIR MOVES OVER THE REGION BY  
SUNDAY/MONDAY KEEPING ISOLATED CONVECTION MAINLY SOUTH OF HIGHWAY  
50.  
 
AFTERNOON WINDS MAY BE SLIGHTLY ENHANCED FROM A TROUGH PASSING  
THROUGH THE PACIFIC NORTHWEST, BUT GUSTS WILL NOT BE MUCH MORE  
THAN TYPICAL AFTERNOON FLOW. EXPECT AFTERNOON GUSTS FROM 20 UP TO  
30 MPH TODAY AND TOMORROW. ALSO ASSOCIATED WITH COOLER  
TEMPERATURES ALOFT FROM A DEVELOPING TROUGH ALONG THE PACIFIC  
COAST, TEMPERATURES WILL BEGIN THEIR SLOW TREND DOWNWARD BEGINNING  
TODAY - WESTERN NEVADA VALLEY HIGHS GENERALLY 98-103 DIPPING TO  
93-100 DEGREES BY MONDAY WITH SIERRA VALLEYS RUNNING 10-13 DEGREES  
COOLER. FORTUNATELY, OVERNIGHT LOWS WILL ALSO BEGIN TO FOLLOW A  
SIMILAR TREND ALLOWING FOR SOME RELIEF FROM RECENT VERY WARM  
MORNINGS. BOYD  
   
LONG TERM (TUESDAY ONWARD)
 
 
GUIDANCE CONTINUES TO SHOW GENERAL TROUGHINESS ALONG THE WEST COAST  
NEXT WEEK. THIS WILL LEAD MUCH DRIER CONDITIONS FOR OUR REGION WITH  
PRECIP WATER VALUES DROPPING TO BELOW NORMAL FOR EARLY AUGUST. EVEN  
SOME 10TH PERCENTILE VALUES IN NAEFS MEANS NORTH OF SUSANVILLE-  
WINNEMUCCA. ALSO WITH INCREASED FLOW ALOFT WE'LL SEE PERIODS OF  
MODERATE WESTERLY WINDS, PRIMARILY TUESDAY AFTERNOON-EVENING. THIS  
COMBINES TO RESULT IN SEEING SOME CRITICAL FIRE WEATHER CONDITIONS  
ESPECIALLY IN AREAS ALONG/NORTH OF I-80 WHICH WOULD IMPACT ONGOING  
LARGE FIRES OR RECENT LIGHTNING STARTS. TEMPERATURES WILL REMAIN  
SEASONABLY HOT BUT WITH FLOW PATTERN WE SHOULD NOT SEE EXCESSIVE  
HEAT RETURN TO THE REGION NEXT WEEK. -CHRIS  
 

 
   
AVIATION
 
 
UNSTABLE AIRMASS CONTINUES ACROSS THE REGION, ALBEIT A LITTLE LESS  
SO THAN YESTERDAY. SO WE'RE STILL LOOKING AT POTENTIAL FOR ISOLATED  
AFTERNOON STORMS FROM MMH NORTHWARD ALONG THE HIGH TERRAIN TO EAST  
OF RNO/CXP AND POINTS EAST (NFL/HTH). BEST RISKS SOUTH OF HWY 50.  
WESTERLY ZEPHYR WIND WILL KEEP ANY CONVECTION EAST OF THE TAHOE BASIN  
(TVL/TRK) AND LIKELY EAST OF RNO/CXP. WHILE NOT DIRECTLY IMPACTING  
THESE AIRPORTS STORMS COULD SEND IN STRONG EASTERLY OUTFLOWS IF THEY  
CAN OVERCOME THE ZEPHYR. I'D SAY ONLY ABOUT A 5-10% CHANCE OF A  
DIRECT THUNDERSTORM HIT BETWEEN 20-23Z TO RNO/CXP WITH MVFR RAIN AND  
LIGHTNING. 10-20% AT MMH/NFL/HTH. WILL NOT CARRY VCTS AT RNO/CXP DUE  
TO LOW CONFIDENCE BUT WILL FOR MMH TAF.  
 
DRIER AIRMASS WORKS IN FOR SUNDAY-MONDAY WITH WEAK TO MODERATE  
WESTERLY AFTERNOON WINDS. AIRMASS FROM MMH-HTH-TPH REMAINS SLIGHTLY  
UNSTABLE SO WE CAN'T RULE OUT ISOLATED STORMS IMPACTING THOSE  
LOCATIONS. -CHRIS  
 

 
   
FIRE WEATHER
 
 
MAIN ISSUES ARE CONTINUED RISK OF ISOLATED STORMS THIS WEEKEND AND  
ENHANCED, NEAR CRITICAL GUSTY WINDS THROUGH TUESDAY.  
 
LATEST SIMULATIONS SHOW ISOLATED BUILDUPS AND PERHAPS  
THUNDERSTORMS THIS AFTERNOON AND EARLY EVENING FROM MONO CO NORTH  
TO THE VIRGINIA RANGE NORTH TO NEAR GERLACH. GUIDANCE IS MIXED IN  
COVERAGE SO THAT LOWERS FORECAST CONFIDENCE SOME. BUT IF STORMS  
DEVELOP ERRATIC OUTFLOW GUSTS TO 40 MPH ALONG WITH LIGHTNING WILL  
IMPACT ANY ONGOING WILDFIRES. STORMS WILL BE MOVING SOME SO BRIEF  
PERIODS OF WETTING RAIN ARE POSSIBLE. FOR SUNDAY RISK OF STORMS  
SETTLES SOUTH TO MAINLY MONO-LYON-MINERAL COUNTIES AS DRIER AIR  
WORKS INTO AREAS NORTH OF HWY 50.  
 
A FEW SUBTLE SHORTWAVES ALOFT WILL HELP ENHANCE THE AFTERNOON-  
EVENING WESTERLY WINDS ACROSS THE REGION EACH DAY THROUGH TUESDAY.  
MAIN RISK AREA FOR THIS IS NORTH OF HWY 50 WHERE WE HAVE LARGE  
FIRES ONGOING AND LIKELY SOME LIGHTNING HOLDOVERS FROM RECENT  
STORMS. WINDS COULD IMPACT THESE. GUSTS TO AROUND 30 MPH ARE  
EXPECTED, BUT WE COULD SEE FAVORED/WIND PRONE AREAS GET INTO THE  
30-35 MPH RANGE WHICH IS CRITICAL. HOWEVER COVERAGE OF THOSE  
HIGHER WIND GUSTS SHOULD BE ISOLATED ENOUGH TO PRECLUDE ISSUANCE  
OF A RED FLAG WARNING. BUT WE WILL HEADLINE THE WINDS IN FWF. IF I  
HAD TO PICK ONE DAY TO WATCH IT IS TUESDAY WHERE MORE WIDESPREAD  
30+ GUSTS ARE POSSIBLE AS A MORE PRONOUNCED TROUGH DIPS INTO THE  
REGION PER RECENT GFS. -CHRIS  
 

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

 
 

 
 
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...  
HTTP://WEATHER.GOV/RENO  
 
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