030
FXUS65 KREV 090947
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
247 AM 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
OUR PROLONGED STRETCH OF SIGNIFICANT HEAT IS ENTERING IT'S FINAL
COUPLE OF DAYS BEFORE NOTICEABLY COOLER TEMPERATURES ARRIVE TUESDAY
ONWARD. UNTIL THEN, DAYTIME HIGHS REMAIN IN THE UPPER 80S TO 90S FOR
SIERRA COMMUNITIES AND UPPER 90S TO 105F ACROSS LOWER NE CA/W NV
VALLEYS. WHILE MANY SIERRA AND NE CALIFORNIA LOCALES COOL OFF NICELY
EACH NIGHT, TEMPERATURES WILL ONLY FALL TO MID 60S AND 70S THROUGH
MONDAY MORNING ACROSS W NEVADA VALLEYS -- OFFERING LITTLE TO NO
RELIEF FROM THE DAYTIME HEAT. AS MENTIONED, A COOLING TREND WILL
LOWER TEMPERATURES TO SEASONAL AVERAGES AND MITIGATE HEAT IMPACTS BY
THE MIDDLE OF THE WEEK.
DAMPENING OF THE WESTERN RIDGING PATTERN WILL ALLOW FOR MORE
PRONOUNCED TROUGHING TO DEVELOP IN THE EASTERN PACIFIC BASIN TODAY
AND MONDAY. THIS ACHIEVES TWO NOTABLE RESULTS FOR TODAY AND
MONDAY:
1) INCREASED AFTERNOON BREEZES FROM THE OR BORDER SOUTH ALONG THE
SIERRA FRONT, AND 2) GREATEST SHOWER AND THUNDERSTORM CHANCES
CONFINED TO AREAS SOUTH OF US-50. WHILE WINDS WON'T BE UNUSUALLY
STRONG, W/SW GUSTS OF 25-30 MPH (35+ MPH LOCALLY) WILL HEIGHTEN FIRE
CONCERNS (MORE DETAILS IN THE FIRE WEATHER DISCUSSION) AND MAKE FOR
ROUGHER LAKE WATERS IN FAR NE CALIFORNIA AND NW NEVADA EACH
AFTERNOON THROUGH MONDAY.
MEANWHILE, RESIDUAL MID-LEVEL MOISTURE ATOP A DEEP, WELL-MIXED
SUBCLOUD LAYER WILL SUPPORT A LOW PROBABILITY (10-30% CHANCES) OF
SHOWERS AND ISOLATED STORMS THIS AFTERNOON FROM MONO COUNTY EASTWARD
INTO THE BROADER S.LYON-MINERAL-S.CHURCHILL CO REGION. STRONG
OUTFLOW WINDS OF 45-55 MPH REMAIN THE PRIMARY HAZARD WITH TODAY'S
SHOWER AND STORM ACTIVITY, ESPECIALLY IN S.LYON, MINERAL, S.
CHURCHILL COUNTIES WHERE DCAPE VALUES OF 1700+ J/KG COULD SUPPORT
ISOLATED SEVERE GUSTS OF 60+ MPH. THERE IS ALSO A VERY LOW 5% CHANCE
OF LOCALIZED FLASH FLOODING THIS AFTERNOON DUE TO ABUNDANT MOISTURE
AND SLOWER STORM MOTIONS, ESPECIALLY IN HIGHER/STEEPER TERRAIN
THAT RECEIVED ANTECEDENT RAINFALL FRIDAY AND SATURDAY. A BRIEF
DRYING TREND WILL DECREASE SHOWER AND STORM CHANCES TO 15% OR LESS
MONDAY AFTERNOON, STILL FAVORING AREAS SOUTH OF US-50.
LOW PRESSURE CONTINUES TO DEEPEN IN THE EASTERN PACIFIC AS THE WEEK
PROGRESSES, DRAWING DEEPER MOISTURE INTO THE REGION TUESDAY ONWARD.
AS A RESULT, SHOWER AND THUNDERSTORM ACTIVITY SHOULD INCREASE EACH
DAY FROM MID TO LATE WEEK, AND PERHAPS CONTINUE THROUGH THE WEEKEND
DEPENDING ON HOW LONG MOISTURE HANGS AROUND. GIVEN THE MOISTURE
QUALITY, FLASH FLOODING IS FAVORED AS THE MAIN THREAT, NEW LIGHTNING
FIRES AND STRONG OUTFLOWS WILL ALSO BE POSSIBLE WITH THIS WEEK'S
THUNDERSTORM ACTIVITY.
-SALAS
AVIATION
SHOWERS AND THUNDERSTORMS RETURN TO THE FORECAST THIS AFTERNOON
FOR KMMH, KBAN, AND KHTH WITH CHANCES INCREASING TO 10-30%. STRONG
OUTFLOW GUSTS OF 45 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
WIND MIXING IT OUT, THEN SMOKE WILL SETTLE IN THE OVERNIGHT HOURS.
THIS WILL LIKELY CONTINUE INTO MONDAY. KRNO MAY HAVE A HIGHER
LIKELIHOOD OF SMOKE IMPACTS TO SLANTWISE VISIBILITY DUE TO THE
BUG FIRE.
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, HUNTER, DOUBLE
SPRINGS, 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 US-50
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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