893
FXUS65 KREV 091959
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
1259 PM PDT SUN AUG 9 2026
KEY MESSAGES
* SIGNIFICANT HEAT PERSISTS TODAY ACROSS WESTERN NEVADA AND LOWER
SIERRA VALLEYS, WITH A GRADUAL COOLING TREND EXPECTED NEXT WEEK.
* ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON
AND MONDAY, WITH INCREASING COVERAGE AND CHANCES BY MID-WEEK.
* INCREASED BREEZES ELEVATE FIRE AND RECREATION CONCERNS TODAY AND
MONDAY AFTERNOON.
DISCUSSION
THE PROLONGED PERIOD OF SIGNIFICANT HEAT WILL CONTINUE THROUGH
MONDAY MORNING ACROSS THE REGION, PARTICULARLY FOR WESTERN NEVADA
AND LOWER SIERRA VALLEYS. TEMPERATURES COOL SLIGHTLY ON MONDAY,
THOUGH A MORE NOTICEABLE COOLING TREND BEGINS TUESDAY, WITH
TEMPERATURES DIPPING BELOW SEASONAL AVERAGES BY WEDNESDAY. A
BROAD UPPER-LEVEL RIDGE CENTERED OVER THE FOUR CORNERS REGION
CONTINUES TO DOMINATE THE WEATHER PATTERN TODAY, MAINTAINING
ABOVE-NORMAL TEMPERATURES. DAYTIME HIGHS TODAY AND MONDAY WILL
GENERALLY BE IN THE UPPER 90S TO 104F FOR LOWER VALLEYS, WITH
SIERRA COMMUNITIES SEEING UPPER 80S TO LOW 90S. OVERNIGHT LOWS
WILL CONTINUE TO OFFER LITTLE RELIEF DUE TO LINGERING CLOUD COVER,
REMAINING IN THE MID 60S TO LOW 70S ACROSS WESTERN NEVADA VALLEYS
THROUGH MONDAY MORNING.
INCREASED AFTERNOON BREEZES ARE EXPECTED TODAY AND MONDAY
AFTERNOON, WITH W/SW GUSTS OF 25-30 MPH (LOCALLY 35+ MPH),
PARTICULARLY ALONG THE SIERRA FRONT AND ACROSS FAR NE
CALIFORNIA/NW NEVADA. THIS WILL ELEVATE FIRE WEATHER CONCERNS
TODAY AND MONDAY FOR THOSE AREAS, ESPECIALLY DUE TO ACTIVE,
ONGOING WILDFIRES ACROSS WESTERN NV. HAZE AND AREAS OF SMOKE FROM
REGIONAL WILDFIRES WILL ALSO PERSIST ACROSS WESTERN NV AND INTO NE
CA TODAY AND MONDAY.
HI-RES MODEL SOUNDINGS IN THE PRE-CONVECTIVE ENVIRONMENT SHOW
RESIDUAL MID-LEVEL MOISTURE ATOP A DEEP, WELL-MIXED SUBCLOUD
LAYER, SUPPORTING ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
THIS AFTERNOON. THE GREATEST CHANCES (10-30%) WILL BE CONFINED TO
AREAS SOUTH OF I-80, INCLUDING MONO, S.LYON, MINERAL, AND
CHURCHILL COUNTIES. DCAPE VALUES OF 1400-1800 J/KG AND LCL
HEIGHTS 3000-4000M SUPPORT THE POTENTIAL FOR STRONG OUTFLOW
WINDS, WHICH REMAIN THE PRIMARY HAZARD WITH TODAY'S ACTIVITY.
GUSTS OF 45-55 MPH AND ISOLATED SEVERE GUSTS OF 60+ MPH POSSIBLE,
ESPECIALLY IN S.LYON, MINERAL, AND S. CHURCHILL COUNTIES. A VERY
LOW (5%) CHANCE OF LOCALIZED FLASH FLOODING EXISTS, MAINLY IN
HIGHER/STEEPER TERRAIN THAT RECEIVED PREVIOUS RAINFALL.
SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED TO CONTINUE EARLY
THIS WEEK OVER MONO/MINERAL COUNTIES, THEN INCREASE EACH DAY FROM
MID-WEEK THROUGH THE WEEKEND. WITH CHANCES FOR MULTIPLE DAYS OF
REPEATED SHOWERS AND THUNDERSTORMS, FLASH FLOODING CONCERNS WILL
INCREASE ACROSS PORTIONS OF THE EASTERN SIERRA AND MINERAL COUNTY,
ESPECIALLY OVER URBAN AREAS AND STEEP TERRAIN. WHILE T-STORMS LATE
IN THE WEEK ARE FAVORED TO BE ON THE WETTER SIDE WITH PWATS
0.6-0.9", NEW LIGHTNING IGNITIONS AND GUSTY OUTFLOW WINDS CANNOT
BE RULED OUT. MODEL GUIDANCE GENERALLY AGREES ON THIS OVERALL
TREND OF INCREASING MOISTURE AND CONVECTIVE ACTIVITY, WITH THE
MAIN UNCERTAINTIES REVOLVING AROUND THE EXACT TIMING AND SPATIAL
DISTRIBUTION OF THE HEAVIEST RAINFALL.
-JUSTIN
AVIATION
SHOWERS AND THUNDERSTORMS RETURN TO THE FORECAST THIS AFTERNOON
FOR KMMH AND KHTH WITH CHANCES INCREASING TO 10-30%. STRONG,
ERRATIC OUTFLOW GUSTS OF 40-50 KTS, BRIEF HEAVY RAIN, AND
OCCASIONAL LIGHTNING ARE THE MAIN HAZARDS WITH ANY THUNDERSTORMS.
CHANCES DECREASE TO 15% OR LESS MONDAY AFTERNOON AND FAVOR A
SIMILAR AREA AS TODAY.
SMOKE FILTERING DOWN INTO FAR NW NV AND NE CA FROM WILDFIRES IN
OREGON MAY REDUCE SLANTWISE VISIBILITIES ACROSS THOSE AREAS.
CONDITIONS ARE EXPECTED TO IMPROVE IN THE AFTERNOON HOURS DUE TO
AFTERNOON BREEZES DIFFUSING IT, THEN SMOKE WILL SETTLE AGAIN IN
THE OVERNIGHT HOURS. THIS WILL LIKELY CONTINUE INTO MONDAY,
POSSIBLY TUESDAY AS WELL. KRNO MAY HAVE A HIGHER LIKELIHOOD OF
SMOKE IMPACTS TO SLANTWISE VISIBILITY DUE TO THE BUG FIRE AND
OTHER FIRES NORTH OF RENO.
OTHERWISE, WIDESPREAD VFR CONDITIONS AND TYPICAL AFTERNOON BREEZES
PREVAIL THIS WEEKEND WITH CONTINUED HEAT POSING DENSITY ALTITUDE
CONCERNS.
-JYLER
FIRE WEATHER
BREEZY W/SW WINDS WITH GUSTS OF 25-35 MPH AND RH REDUCTIONS TO 5-15%
WILL SUPPORT 2-5 HOURS OF ELEVATED TO MARGINALLY CRITICAL FIRE
WEATHER CONDITIONS THIS AFTERNOON AND MONDAY AFTERNOON ACROSS FAR NE
CALIFORNIA AND NW NEVADA -- INCLUDING THE BUG, IRONWOOD, FRED,
AND RUBY FIRES IN THE SIERRA FRONT. NIGHTTIME RECOVERIES REMAIN
POOR EACH NIGHT THROUGH TUESDAY AM AS RH STRUGGLES TO EXCEED
30-40%, EXTENDING BURN PERIODS INTO THE OVERNIGHT HOURS.
THERE IS A LOW 10-30% PROBABILITY OF THUNDERSTORMS SOUTH OF I-80
TODAY AND MONDAY AFTERNOON, POSING A RISK OF NEW LIGHTNING
IGNITIONS AND STRONG AND ERRATIC OUTFLOW GUSTS OF 50+ MPH.
MOREOVER, AN UNSTABLE AIRMASS WILL ALLOW FOR DEEPER VERTICAL PLUME
GROWTH EACH AFTERNOON, INCREASING THE LIKELIHOOD OF LOCALLY
STRONGER INFLOW WINDS NEAR THE FIRE, AND SUDDEN/ERRATIC DOWNDRAFT
WINDS FROM COLLAPSING PLUMES.
A PATTERN CHANGE BRINGS COOLER TEMPERATURES AND HIGHER HUMIDITY FROM
TUESDAY ONWARD, BUT ALSO INCREASING CHANCES OF THUNDERSTORMS.
THUNDERSTORMS ARE FAVORED TO BE WET WITH HEAVY RAIN/FLOODING IMPACTS
TO OPERATIONS, BUT NEW LIGHTNING STARTS AND GUSTY OUTFLOW WINDS
CANNOT BE RULED OUT.
-SALAS
REV WATCHES/WARNINGS/ADVISORIES
NV...HEAT ADVISORY UNTIL 8 AM PDT MONDAY NVZ001-003-005.
EXTREME HEAT WARNING UNTIL 8 AM PDT MONDAY NVZ004.
CA...HEAT ADVISORY UNTIL 8 AM PDT MONDAY CAZ070-071.
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