982  
FXUS65 KREV 260257  
AFDREV  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE RENO NV  
757 PM PDT MON MAR 25 2019  
   
UPDATE
 
 
GUSTY WINDS ACROSS THE WESTERN PART OF NEVADA AND IN THE SIERRA  
ARE STARTING TO DECREASE...BUT WITH LIMITED PRECIPITATION MAKING  
ITS WAY OVER THE SIERRA CREST INTO THE TAHOE BASIN WE DO NOT THINK  
THE WINDS WILL DECREASE AS FAST AS PREVIOUSLY FORECAST.  
THEREFORE...WE WILL EXTEND THE LAKE WIND ADVISORY FOR LAKE TAHOE  
FOR A FEW MORE HOURS. THE GUSTY WINDS AROUND TAHOE SHOULD  
DECREASE LATE TONIGHT AS PRECIPITATION STARTS TO MOVE IN. IN  
WESTERN NEVADA...GUSTY WINDS ARE STILL LIKELY AT PYRAMID  
LAKE...BUT THE LAKE IS NOW CLOSED FOR THE NIGHT. WE WILL LET THAT  
ADVISORY EXPIRE.  
 
LIGHT SNOW HAS MOVED INTO FAR WESTERN LASSEN COUNTY WITH SOME  
ACCUMULATION DEVELOPING IN THE BOGARD AREA. LIGHT SNOW IS ALSO  
SHOWN BY RADAR IN CENTRAL PLUMAS COUNTY. SOUTH WINDS NEAR THE  
SURFACE AND ALOFT UP TO ABOUT 10K FT SHOULD KEEP THIS  
PRECIPITATION FROM MOVING VERY FAR EAST UNTIL THE UPPER LEVEL JET  
SLIDES FARTHER EAST TUESDAY MORNING. WE WILL KEEP THE WINTER  
WEATHER ADVISORY FOR LASSEN/PLUMAS/SIERRA COUNTIES IN EFFECT  
TONIGHT AND EARLY TOMORROW...BUT THE MAIN STORM SYSTEM AFFECTS THE  
REGION TUESDAY NIGHT INTO WEDNESDAY/THURSDAY.  
 

 
   
PREVIOUS DISCUSSION
 
/ISSUED 241 PM PDT MON MAR 25 2019/  
 
SYNOPSIS...  
 
A SERIES OF LATE SEASON STORMS WILL IMPACT THE REGION THIS WEEK  
WITH GUSTY WINDS, HEAVY MOUNTAIN SNOW, AND PERIODS OF VALLEY RAIN.  
THE GREATEST IMPACTS TO TRAVEL IN THE SIERRA AND WESTERN NEVADA  
ARE EXPECTED LATE TUESDAY NIGHT THROUGH WEDNESDAY. DRIER AND  
WARMER CONDITIONS WILL LIKELY RETURN BY THE WEEKEND.  
 
SHORT TERM...  
 
THE MAIN CHANGES IN THE ACTIVE SHORT TERM PERIOD WERE A CONTINUED  
REDUCTION OF SNOW ACCUMULATIONS FOR THE MID-RANGE ELEVATIONS  
(5000-7000 FEET) AS MORE OF THE HEAVIER PRECIP RATES ARE ANTICIPATED  
FOR THE DAYTIME HOURS ON WEDNESDAY. HOWEVER, ABOVE 7000 FEET IN  
THE SIERRA AND ABOVE 5500 FEET IN NORTHEAST CA, WE'RE STILL  
EXPECTING SUFFICIENT SNOWFALL AND TRAVEL IMPACTS OVER HIGHER  
SEGMENTS OF MOST PASSES, SO WE WILL UPGRADE THE WATCH TO A WINTER  
STORM WARNING FROM LATE TUESDAY EVENING THROUGH WEDNESDAY EVENING.  
 
BEFORE THIS MAIN STORM, A LEADING TROUGH ACCOMPANIED BY A NARROW  
FEED OF DEEPER SUBTROPICAL MOISTURE IS MOVING SLOWLY ACROSS NORTH  
CENTRAL CA, HAVING PRODUCED BETWEEN 0.40-0.70" OF RAIN ALONG PARTS  
OF THE I-5 CORRIDOR IN THE NORTHERN SACRAMENTO RIVER VALLEY. WE'VE  
ALSO SEEN SOME LOCALLY STRONG WIND GUSTS AROUND 65 MPH IN PARTS  
OF NORTHEAST CA AND BRIEFLY AT US-395 RED ROCK NORTH OF RENO, AND  
50-60 MPH GUSTS ALONG I-580 SOUTH OF RENO. THIS ISN'T LIKELY TO BE  
A WIDESPREAD STRONG WIND EVENT, SO THE ONGOING SPECIAL WEATHER  
STATEMENT WILL BE CONTINUED.  
 
WHILE FORCING WEAKENS TONIGHT AS THIS PRECIP MOVES INTO NORTHEAST  
CA, IT DOESN'T COMPLETELY GO AWAY, WITH THE NARROW MOISTURE FEED  
REMAINING INTACT SO WE'RE KEEPING THE HIGH PRECIP CHANCES AND THE  
WINTER WEATHER ADVISORY IN EFFECT. THIS IS A LOW END SNOW-PRODUCER  
SO WE'RE NOT EXPECTING MUCH CHANGE FROM THE ORIGINAL 2-5" SNOWFALL  
POTENTIAL, MAINLY AFFECTING HIGHER NORTHEAST CA PASSES SUCH AS  
FREDONYER, YUBA, AND MAYBE CA-44 WEST OF SUSANVILLE. AS THIS  
MOISTURE BAND EDGES SLOWLY SOUTH BY EARLY TUESDAY MORNING, UP TO  
6" OF SNOW MAY ALSO ACCUMULATE NEAR THE SIERRA CREST WEST OF  
TAHOE, AND MAYBE AN INCH OR SO DOWN TO LAKE LEVEL. MUCH OF THIS  
SNOW IS LIKELY TO HAVE A DIFFICULT TIME STICKING TO RELATIVELY  
WARM PAVEMENT, SO WE'RE NOT PLANNING ANY ADVISORIES FOR THE TAHOE  
AREA. A WEAK UPPER DISTURBANCE ACTUALLY BRINGS A BIT MORE FORCING  
DURING THE DAY TUESDAY, WITH MODEST SPILLOVER RAIN SHOWERS INTO  
PARTS OF WESTERN NV, WITH A RAIN-SNOW MIX CONTINUING FOR THE TAHOE  
BASIN AND PARTS OF NORTHEAST CA. MODERATELY GUSTY WINDS OF 30-40  
MPH WILL CONTINUE, WITH SIERRA RIDGE GUSTS UP TO 70 MPH (OVERALL  
SPEEDS A BIT LOWER THAN TODAY).  
 
AFTER A BREAK IN MOST PRECIP ACTIVITY TUESDAY EVENING, THE MAIN  
WAVE OF MOISTURE ASSOCIATED WITH THE STORM SYSTEM ARRIVES LATE  
TUESDAY NIGHT, WITH PEAK PRECIP RATES LIKELY DURING THE DAY  
WEDNESDAY WHEN FORCING IS MAXIMIZED, ALONG WITH FAVORABLE UPPER  
JET DYNAMICS LINING UP DURING THE AFTERNOON. SNOWFALL RATES OF  
1-2"/HOUR ARE LIKELY TO BE MAINTAINED FOR THE HIGHER ELEVATIONS,  
WITH EVEN BRIEFLY HIGHER RATES POSSIBLE IN THE AFTERNOON AS  
CONVECTION WEST OF THE CREST BECOMES EMBEDDED WITHIN THE MAIN  
MOISTURE BAND. WE'RE STILL ANTICIPATING STORM TOTALS OF 1-2 FEET  
ALONG THE SIERRA CREST ABOVE 7000 FEET AND 8-16" IN NORTHEAST CA  
ABOVE 5500 FEET, ALTHOUGH THE HIGH END POSSIBILITY OF 3 FEET IS  
UNLIKELY DUE TO SHORTER STORM DURATION. BELOW THESE ELEVATIONS,  
THE AMOUNT OF ACCUMULATING SNOW WILL DROP OFF SIGNIFICANTLY, AND  
LAKE LEVEL AREAS AROUND TAHOE/TRUCKEE MAY END UP WITH ONLY A  
COUPLE NEW INCHES ON THE GROUND AS THE SNOW TAPERS FROM NORTH TO  
SOUTH WEDNESDAY EVENING. SOME OF THESE AREAS MAY STILL HAVE SNOW  
FALLING FOR SEVERAL HOURS, BUT NOT STICKING TO PAVED SURFACES.  
 
FOR WESTERN NV, PERIODS OF SPILLOVER MOISTURE ARE EXPECTED AT  
TIMES ON WEDNESDAY, WITH PRECIP AMOUNTS GENERALLY BETWEEN  
0.25-0.50" AROUND RENO-CARSON-MINDEN, AND 0.25" OR LESS FOR MOST  
OF WEST CENTRAL NV. FOR PARTS OF THE BASIN AND RANGE, ISOLATED  
FAST MOVING THUNDERSTORM CELLS COULD FORM WEDNESDAY AFTERNOON AS  
THE NOSE OF THE UPPER JET MOVES THROUGH, WHILE MILDER TEMPS IN  
THESE AREAS SHOULD ALLOW FOR JUST ENOUGH INSTABILITY FOR A FEW  
LIGHTNING STRIKES, AND LOCALLY HEAVIER RAINFALL AMOUNTS. RAIN MAY  
END AS A BRIEF PERIOD OF SNOW WEDNESDAY EVENING ABOVE 5000-5500  
FEET IN WESTERN NV BUT LITTLE OR NO ACCUMULATION IS EXPECTED.  
GUSTY WINDS WITH SPEEDS SIMILAR TO TODAY ARE ANTICIPATED,  
ALTHOUGH THE INCREASED PRESENCE OF PRECIP COULD REDUCE THE  
DURATION AND EXTENT OF THESE WINDS. MJD  
 
LONG TERM...THURSDAY THROUGH SUNDAY...  
 
A WEAK UPPER LOW CROSSES FROM WEST TO EAST ON THURSDAY, ALLOWING  
SNOW OR SNOW PELLET SHOWERS TO CONTINUE ACROSS THE EASTERN SIERRA  
AND BRINGING A CHANCE FOR SHOWERS TO WESTERN NV. BREEZY WINDS WILL  
ALSO CONTINUE THROUGH THURSDAY. PRECIPITATION IS EXPECTED TO BE  
LIGHT, BUT SNOW LEVELS WILL BE LOWER AND SOME OF THE SHOWERS COULD  
PRODUCE A QUICK INCH OR TWO OF SNOW ABOVE 5000 FEET. THUS, BRIEF  
IMPACTS TO TRAVEL ARE POSSIBLE THURSDAY AS THESE SHOWERS BRING  
VARIABLE CONDITIONS THROUGHOUT THE DAY. BELOW 5000 FEET SNOW  
PELLETS OR A RAIN/SNOW MIX ARE POSSIBLE.  
 
ANOTHER WEAK UPPER LOW COULD BRING YET ANOTHER PERIOD OF SCATTERED  
SHOWERS FRIDAY, WITH THE BEST CHANCES NORTH OF I-80 DURING THE  
AFTERNOON.  
 
A HIGH PRESSURE RIDGE OFFSHORE SHOULD LEAD TO PARTLY CLOUDY SKIES  
THIS WEEKEND WITH WARMER AFTERNOON TEMPERATURES. EXPECT AFTERNOON  
TEMPERATURES IN WESTERN NV IN THE 50S AND 60S. HOWEVER, THERE ARE  
SOME INDICATIONS A WEAK SYSTEM COULD RIDE OVER THE RIDGE BY THE  
END OF THE WEEKEND. THIS COULD BRING A RETURN OF CLOUDS AND  
POSSIBLY SHOWERS SUNDAY OR MONDAY, ESPECIALLY FOR NORTHERN  
CALIFORNIA, BUT FORECAST CONFIDENCE IS VERY LOW. JCM  
 
AVIATION...  
 
A SERIES OF STORMS WILL IMPACT THE REGION THROUGH AT LEAST THURSDAY.  
 
IFR/MVFR CONDITIONS AND MOUNTAIN OBSCURATIONS ARE LIKELY IN THE  
SIERRA TONIGHT THROUGH TUESDAY. AT KTRK/KTVL/KMMH AROUND AN INCH  
OF SLUSHY SNOW IS EXPECTED, WITH CHANCES FOR LIGHT RAIN AT  
KRNO/KTRK. CEILINGS AND VISIBILITIES WILL DEGRADE FURTHER EARLY  
WEDNESDAY MORNING AS A SECOND WAVE OF HEAVIER PRECIPITATION MOVES  
INTO THE REGION. MODERATE SNOW IS POSSIBLE AT KTVL/KTRK/KMMH AND  
MOSTLY RAIN AT KRNO/KCXP.  
 
REGARDING WINDS, TURBULENCE AND OCCASIONAL LOW LEVEL WIND SHEAR  
WILL PERSIST THROUGH THIS AFTERNOON. SURFACE GUSTS PEAKING IN THE  
30-40 KT RANGE WILL ALSO PERSIST INTO THIS AFTERNOON AND THEN  
SHOULD BEGIN TO DECREASE BY 03Z. BREEZY/TURBULENT CONDITIONS  
RETURN TUESDAY AFTERNOON, BUT ARE NOT FORECAST TO BE AS STRONG AS  
TODAY. BUT THEN FOR LATE TUESDAY NIGHT THROUGH WEDNESDAY, ANOTHER  
PERIOD OF STRONGER WINDS AND TURBULENCE IS LIKELY. JCM  
 

 
   
REV WATCHES/WARNINGS/ADVISORIES
 
 
NV...WINTER STORM WARNING FROM 11 PM TUESDAY TO 11 PM PDT WEDNESDAY  
ABOVE 7000 FEET IN NVZ002.  
 
LAKE WIND ADVISORY UNTIL 11 PM PDT THIS EVENING FOR LAKE TAHOE  
IN NVZ002.  
 
CA...WINTER WEATHER ADVISORY UNTIL 8 AM PDT TUESDAY ABOVE 5000 FEET  
IN CAZ071.  
 
WINTER STORM WARNING FROM 11 PM TUESDAY TO 11 PM PDT WEDNESDAY  
ABOVE 5500 FEET IN CAZ071.  
 
WINTER STORM WARNING FROM 11 PM TUESDAY TO 11 PM PDT WEDNESDAY  
ABOVE 7000 FEET IN CAZ072-073.  
 
LAKE WIND ADVISORY UNTIL 11 PM PDT THIS EVENING FOR LAKE TAHOE  
IN CAZ072.  
 

 
 

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