718  
FXUS65 KREV 111943  
AFDREV  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE RENO NV  
1243 PM PDT SUN APR 11 2021  
   
SYNOPSIS
 
 
IT WILL REMAIN WARM AND DRY THROUGH MONDAY WITH GENERALLY LIGHT  
WINDS. WINDS WILL INCREASE, BECOMING GUSTY SOUTH OF US-50,  
TUESDAY AS A COLDER SYSTEM DROPS INTO THE REGION. THIS SYSTEM WILL  
BRING COLDER TEMPERATURES ALONG WITH CHANCES FOR SHOWERS, THOUGH  
IT DOES NOT LOOK TO BE A MAJOR PRECIPITATION PRODUCER. SIMULATIONS  
FAVOR WARMER AND DRIER CONDITIONS BY THE FOLLOWING WEEKEND.  
 

 
   
DISCUSSION
 
 
ANOTHER DRY AND SEASONABLY WARM DAY WITH AFTERNOON HIGHS EXPECTED  
TO PEAK 5-8 DEGREES ABOVE AVERAGE AS A HIGH PRESSURE RIDGE SITS  
OFF THE WEST COAST. SIMILAR CONDITIONS ARE FORECAST FOR MONDAY  
WITH LIGHT EAST-NORTHEASTERLY FLOW IN PLACE AS WINDS SHIFT TO THE  
SOUTHWEST ALONG THE EASTERN SIERRA. SOME CUMULUS BUILD-UPS ARE  
POSSIBLE MONDAY AFTERNOON ALONG THE SIERRA CREST AND INTO THE  
TAHOE BASIN, HOWEVER CHANCES FOR AN ISOLATED THUNDERSTORM TO  
DEVELOP REMAIN LOW (5-10%).  
 
THE WEATHER PATTERN BEGINS TO CHANGE LATE MONDAY NIGHT THROUGH  
WEDNESDAY AS AN UPPER-LEVEL LOW PRESSURE SYSTEM DROPS SOUTHWARD  
OVER THE REGION FROM THE PACIFIC NORTHWEST.  
 
TEMPERATURES: CONFIDENCE REMAINS HIGH IN COOLER TEMPERATURES FOR  
TUESDAY AND WEDNESDAY WITH HIGHS A FEW DEGREES BELOW AVERAGE FOR  
MID-APRIL. GFS 700 MB TEMPERATURES ARE BETWEEN -7 AND -5 DEGREES  
CELSIUS WEDNESDAY AFTERNOON (THE CHILLIEST DAY OF THIS WEEK) WHICH  
WOULD TRANSLATE TO SURFACE TEMPERATURES IN THE MID TO UPPER 50S  
REGION-WIDE, OF COURSE ABOUT 5-10 DEGREES COOLER IN THE  
MOUNTAINS. A WARMING TREND LOOKS TO BEGIN ON THURSDAY WITH A  
RETURN TO ABOVE AVERAGE TEMPERATURES FOR THE WEEKEND.  
 
PRECIPITATION: NOT MUCH CHANGE TO OUR OVERALL THINKING REGARDING  
PRECIPITATION WITH THIS SYSTEM. EVEN THOUGH MEDIUM CONFIDENCE  
EXISTS IN SCATTERED CHANCE POPS (25-40%) FOR TUESDAY INTO  
WEDNESDAY, QPF REMAINS LOW AT THIS TIME AND TO BE HONEST WILL  
PROBABLY REMAIN LOW WITH THIS STORM GIVEN ITS DIFFICULT FORECAST  
NATURE. CUT-OFF, SPRING TIME LOWS WITH A LIMITED MOISTURE SOURCE  
MOST OF THE TIME RESULT IN MOSTLY CLOUDY SKIES WITH ISOLATED TO  
SCATTERED RAIN/HIGH ELEVATION SNOW SHOWERS ACROSS MOST OF THE  
REGION. PELLET SHOWERS AND A RUMBLE OF THUNDER ARE ALSO ON THE  
TABLE DURING THE AFTERNOON HOURS AS THE COLD POOL OF THE LOW SITS  
OVERHEAD COUPLED WITH SOME DAYTIME SURFACE HEATING LEADING TO  
UNSTABLE CONDITIONS. CURRENT NBM TOTAL QPF PROJECTIONS SHOW A ~15%  
CHANCE FOR 0.10" FOR RENO AND SOUTH LAKE TAHOE WITH A 25% CHANCE  
OF AN INCH OR TWO OF SNOW FOR THE SIERRA CREST BY WEDNESDAY  
EVENING.  
 
WINDS: MOST LIKELY THE MAIN IMPACT, WITH CONFIDENCE INCREASING,  
IS THE POTENTIAL FOR GUSTY SOUTHWEST WINDS AND AN ELEVATED FIRE  
RISK FOR MONO AND MINERAL COUNTIES FOR TUESDAY AFTERNOON. ENHANCED  
NORTH TO NORTHWEST WINDS ARE FORECAST FROM US-50 NORTHWARD WITH  
GUSTS OF 25-35 MPH RESULTING IN PROBABLE BLOWING DUST IN THE BASIN  
AND RANGE AND ROUGH CONDITIONS ON AREA LAKES. THE MAIN CONCERN IS  
FOR LOCATIONS SOUTH OF US-50 WHERE THE STRONGEST WIND GUSTS ARE  
ANTICIPATED AS THE SYSTEM'S FRONT PUSHES THROUGH TUESDAY  
AFTERNOON/EVENING. MULTIPLE FORECASTING TOOLS THIS MORNING,  
INCLUDING THE ECMWF GUST ENSEMBLE, THE ICON, AND NBM, ALL SHOW  
GUSTS IN THE 40-50 MPH RANGE FROM 2 PM - 8 PM TIMEFRAME ON  
TUESDAY. HIGHER GUSTS ARE POSSIBLE ALONG THE SIERRA RIDGES AND FOR  
WIND PRONE LOCATIONS ON US-395 SUCH AS BRIDGEPORT, WALKER, AND  
LUNDY. EVEN THE ECMWF EXTREME FORECAST INDEX (EFI) HIGHLIGHTS  
SOUTHERN ALPINE AND MONO COUNTY WITH ABOVE AVERAGE WIND GUSTS  
DURING THIS TIME PERIOD FOR THIS TIME OF YEAR. SYNOPTICALLY  
SPEAKING, THIS POTENTIAL OUTCOME MAKES SENSE GIVEN THE UPPER-  
LEVEL JET SUPPORT ACCOMPANYING THE FRONTAL PASSAGE TAKING PLACE  
DURING PEAK MIXING TIME. THESE STRONG WINDS COUPLED WITH A BRIEF,  
PRE-FRONTAL PERIOD OF LOW HUMIDITY (15% OR BELOW) HAS INCREASED  
OUR CONFIDENCE IN AN ELEVATED FIRE RISK FOR MONO AND MINERAL  
COUNTIES. FOR MORE INFORMATION, PLEASE SEE THE FIRE WEATHER  
DISCUSSION BELOW.  
 
AS FOR THE REMAINDER OF THE FORECAST FROM THURSDAY INTO NEXT  
WEEKEND, LIGHTER NORTH-NORTHEASTERLY WINDS AND IMPROVING  
CONDITIONS WITH A WARMING TREND IS LIKELY. WE COULD SEE A FEW WEAK  
WAVES PUSH THROUGH THE REGION FRIDAY AND AGAIN SATURDAY INTO  
SUNDAY FROM THE NORTHEAST AS THE LOW PRESSURE SYSTEM EXITS SLOWLY  
TOWARDS THE EAST WITH RIDGING BUILDING IN THEREAFTER FROM THE WEST.  
-LAGUARDIA  
 

 
   
AVIATION
 
 
VFR CONDITIONS REMAIN THROUGH MONDAY WITH LIGHT EASTERLY FLOW AT  
THE SURFACE AND SOME HIGH CLOUDS. COULD SEE SOME CUMULUS BUILD-UPS  
ALONG THE SIERRA AND AROUND THE TAHOE BASIN MONDAY LATE  
AFTERNOON/EVENING, BUT THE CHANCE FOR AN ISOLATED THUNDERSTORM TO  
DEVELOP REMAINS LOW (~5-10%).  
 
CONDITIONS BEGIN TO DETERIORATE ACROSS THE REGION LATE MONDAY  
NIGHT INTO TUESDAY AS A LOW PRESSURE SYSTEM DROPS FROM THE NORTH.  
MAIN IMPACTS TO AREA TERMINALS WILL BE GUSTY WINDS, PERIODS OF  
LLWS, AND SOME TURBULENCE AS THE SYSTEM'S FRONT PUSHES THROUGH  
TUESDAY AFTERNOON/EVENING. NORTH TO NORTHWEST WINDS WILL BE  
ENHANCED FOR TERMINALS NORTH OF US-50 (KSVE-KTRK-KRTS-KRNO-KCXP-  
KLOL-NFL) WITH GUSTS 25-30 KTS POSSIBLE DURING THIS TIME. THE  
STRONGEST GUSTS FROM THE SOUTHWEST ARE EXPECTED TO TAKE PLACE FOR  
AREAS SOUTH OF US-50, INCLUDING KMMH AND KHTH, WITH GUSTS 30-45  
KTS POSSIBLE.  
 
WITH THE INCREASED WINDS TUESDAY AFTERNOON, BLOWING DUST IS  
LIKELY IN THE NEVADA BASIN AND RANGE. WE COULD SEE SHOWERS ON  
TUESDAY INTO WEDNESDAY AS WELL, BUT THIS WILL BE MORE HIT OR MISS.  
THESE SHOWERS COULD BRING SOME AREAS OF TERRAIN OBSCURATION.  
-LAGUARDIA  
 

 
   
FIRE WEATHER
 
 
TODAY IS OUR FIRST DAY OF 2X/DAY FIRE WEATHER FORECASTS, WHICH MEANS  
WE ARE IN "HIGH SEASON" FOR FIRE WEATHER. THIS MEANS YOU WILL SEE  
UPDATED AFTERNOON FIRE WEATHER PLANNING FORECASTS (FWF) AND ECCDA  
(FWL) DISCUSSIONS EACH DAY.  
 
WE AREN'T THE FUELS EXPERTS, BUT FROM THE INTEL THAT WE HAVE  
RECEIVED THIS IS WHAT WE KNOW:  
 
GREEN UP HAS BARELY BEGUN ACROSS THE AREA, SO MANY LOCATIONS ARE  
STILL CAPABLE OF BURNING, ESPECIALLY FOOTHILLS AND VALLEYS BELOW  
5500 FEET. MULTIPLE SITES AROUND THE EASTERN SIERRA AND WESTERN  
NEVADA ARE AT "PEAK FIRE SEASON" VALUES. PARTNERS IN THE SOUTHERN  
SIERRA FRONT HAVE REPORTED THAT LIVE FUEL MOISTURES ARE 103%/108%.  
VALUES BELOW 125% ARE CONSIDERED CRITICAL. THERE IS A LACK OF  
GRASS CROP ACROSS THE LOWER ELEVATIONS, SO WE HAVE THAT GOING FOR  
US.  
 
TUESDAY IN THE LOWER EASTERN SIERRA WILL BE THE PRIMARY FIRE CONCERN  
TIME/LOCATION THIS WEEK. A LOW PRESSURE SYSTEM WILL DROP THROUGH THE  
GREAT BASIN TUESDAY/WEDNESDAY WHICH WILL BRING A NOTABLE COOLDOWN IN  
TEMPERATURES, INCREASED HUMIDITY, AND SOME CHANCES FOR SHOWERS.  
UNLIKELY TO BE A WETTING RAIN, BUT THERE WILL BE SOME SHOWERS AROUND  
THE EASTERN SIERRA AND WESTERN NEVADA TUESDAY/WEDNESDAY.  
 
THE PRIMARY CONCERN WILL BE FOR WINDS AHEAD OF AND BEHIND THE COLD  
FRONT: GUSTY SOUTHWEST WINDS AHEAD OF THE FRONT FOR THE SOUTHERN  
SIERRA FRONT AND MINERAL COUNTY, AND THEN BREEZY NORTH WINDS BEHIND  
IT. WIND GUSTS WILL BE IN THE 25 TO 50 MPH RANGE FOR THE SOUTHERN  
SIERRA FRONT IN THE EASTERN SIERRA AS WELL AS AREAS OF MINERAL  
COUNTY. LATEST SIMULATIONS SHOW THAT HUMIDITY VALUES WILL STAY  
BELOW 15% THROUGH THE AFTERNOON AND LIKELY WON'T START TRENDING  
UPWARDS UNTIL AFTER 4PM FOR THOSE AREAS.  
 
WE WILL HEADLINE IN THE FWF THAT THERE MAY BE A COUPLE OF HOURS WITH  
CRITICAL CONDITIONS TUESDAY AFTERNOON, DUE TO GUSTY WINDS AND LOW  
RELATIVE HUMIDITY. MOISTURE WILL INCREASE RAPIDLY WITH THE  
FRONTAL PASSAGE, SO THAT SHOULD HELP TO LIMIT THE LOCALIZED  
CRITICAL CONDITIONS BY LATE AFTERNOON/EVENING. WINDS WILL DECREASE  
A BIT BEHIND THE FRONT, BUT NORTH WINDS WILL REMAIN BREEZY MUCH  
OF THE NIGHT. -EDAN  
 

 
   
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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