029
FXUS65 KREV 081927
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
1227 PM PDT SAT AUG 8 2026
KEY MESSAGES
* DANGEROUS HEAT PERSISTS THROUGH THE WEEKEND ACROSS WESTERN
NEVADA AND LOWER SIERRA VALLEYS, WITH A GRADUAL COOLING TREND
EXPECTED NEXT WEEK.
* ISOLATED TO SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS THIS
AFTERNOON AND SUNDAY, WITH INCREASING COVERAGE AND CHANCES BY
MID-WEEK.
* BREEZY CONDITIONS WILL INCREASE SUNDAY AND MONDAY AFTERNOONS,
ELEVATING FIRE WEATHER CONCERNS AND CREATING CHOPPY LAKE WATERS.
DISCUSSION
THE SYNOPTIC PATTERN FOR THE SHORT TERM REMAINS DOMINATED BY A
BROAD UPPER-LEVEL RIDGE CENTERED OVER THE GREAT BASIN, MAINTAINING
A HOT AND DRY AIRMASS ACROSS THE REGION. MONSOONAL MOISTURE
CONTINUES TO ADVECT INTO THE AREA FROM THE SOUTH ON THE PERIPHERY
OF THE HIGH PRESSURE, PROVIDING FUEL FOR AFTERNOON CONVECTION THE
NEXT SEVERAL DAYS.
DANGEROUS HEAT WILL PERSIST THROUGH THE WEEKEND. HIGH
TEMPERATURES TODAY AND SUNDAY WILL REACH THE UPPER 90S TO LOW 100S
ACROSS WESTERN NEVADA VALLEYS, WITH SOME AREAS POTENTIALLY
EXCEEDING 105F, ESPECIALLY IN LOWER DESERT SINKS. LOWER SIERRA
VALLEYS AND FOOTHILLS WILL SEE HIGHS IN THE 90S, WHILE LAKE TAHOE
AND HIGHER ELEVATIONS OF THE EASTERN SIERRA WILL BE IN THE UPPER
80S TO LOW 90S. OVERNIGHT LOWS WILL OFFER LITTLE RELIEF, GENERALLY
REMAINING IN THE UPPER 60S TO LOW 70S IN THE VALLEYS,
CONTRIBUTING TO WIDESPREAD MODERATE TO MAJOR HEATRISK ACROSS THE
REGION. HEAT ADVISORIES AND AN EXTREME HEAT WARNING REMAIN IN
EFFECT THROUGH MONDAY MORNING. A GRADUAL COOLING TREND WILL BEGIN
ON MONDAY, WITH HIGHS DROPPING BY 10 DEGREES BY WEDNESDAY.
ISOLATED TO SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS ARE
EXPECTED TODAY AND SUNDAY. CONVECTION WILL PRIMARILY BE FOCUSED ON
THE EASTERN SIERRA, S LYON, AND MINERAL COUNTIES (20-30%). LOWER
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE FARTHER
NORTH ALONG THE SIERRA FRONT THIS AFTERNOON AROUND 10-20%. HIGH
DCAPE (1600-1800 J/KG) SUPPORT THE POTENTIAL FOR STRONG OUTFLOW
WINDS (45-55 MPH GUSTS) AS THE PRIMARY HAZARD WITH ANY STORMS THAT
DEVELOP. PWATS AROUND 0.60-0.90" ARE SUFFICIENT FOR BRIEF HEAVY
RAINFALL, ESPECIALLY IN AREAS WITH ANTECEDENT MOISTURE. COVERAGE
IS EXPECTED TO DECREASE SLIGHTLY ON MONDAY AS DRIER AIR BEGINS TO
FILTER IN FROM THE WEST, THOUGH ISOLATED ACTIVITY WILL LIKELY
CONTINUE FOR THE EASTERN SIERRA AND MINERAL COUNTY.
AFTERNOON BREEZES WILL INCREASE THROUGH THE WEEKEND. WESTERLY TO
SOUTHWESTERLY WINDS OF 10-15 MPH WITH GUSTS UP TO 30 MPH ARE
EXPECTED SUNDAY AFTERNOON AND EVENING, PARTICULARLY ALONG THE
SIERRA FRONT AND IN NORTHERN WASHOE COUNTY. THESE INCREASED
WINDS, COMBINED WITH HOT AND DRY CONDITIONS, WILL ELEVATE FIRE
WEATHER CONCERNS. SMOKE FROM PACIFIC NORTHWEST WILDFIRES MAY ALSO
BE DIRECTED INTO LASSEN AND N WASHOE COUNTIES DURING OVERNIGHT
HOURS SUNDAY INTO MONDAY.
LOOKING AHEAD TO NEXT WEEK, THE UPPER-LEVEL RIDGE IS FORECAST TO
GRADUALLY SHIFT EASTWARD, ALLOWING FOR A MORE ZONAL FLOW PATTERN
TO DEVELOP ACROSS THE REGION BY MID-WEEK. MONSOONAL MOISTURE IS
EXPECTED TO INCREASE SIGNIFICANTLY MID-WEEK, LEADING TO HIGHER
CHANCES AND COVERAGE OF SHOWERS AND THUNDERSTORMS, ESPECIALLY
WEDNESDAY THROUGH FRIDAY. WHILE THE PRIMARY THREAT WILL LIKELY
REMAIN STRONG OUTFLOW WINDS, THE INCREASED MOISTURE AND SLOWER
STORM MOTIONS COULD LEAD TO LOCALIZED FLASH FLOOD CONCERNS,
ESPECIALLY IN MONO COUNTY.
-JUSTIN
AVIATION
SHOWERS AND THUNDERSTORMS RETURN TO THE FORECAST THIS AFTERNOON
FOR KMMH, KHTH, AND THE SIERRA FRONT. CHANCES FROM KRNO TO KMEV
ARE 15%, AND INCREASE TO 30% OVER KMMH. PROBABILITIES FOR SHOWERS
AND THUNDERSTORMS BECOME CONFINED TO MONO/MINERAL COUNTIES SUNDAY
AFTERNOON, WITH SIMILAR CHANCES.
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 THROUGH THIS WEEKEND INTO MONDAY.
OTHERWISE, WIDESPREAD VFR CONDITIONS AND TYPICAL AFTERNOON
BREEZES PREVAIL THIS WEEKEND WITH CONTINUED HEAT POSING DENSITY
ALTITUDE CONCERNS.
-JUSTIN
FIRE WEATHER
TYPICAL AFTERNOON ZEPHYR BREEZES OUT OF THE WEST THIS AFTERNOON
AND SUNDAY WITH GUSTS UP TO 30 MPH ACROSS THE SIERRA FRONT, N
WASHOE, AND LASSEN COUNTIES. THIS WILL COMBINE WITH SIGNIFICANT
TRIPLE-DIGIT HEAT TO CREATE ELEVATED FIRE WEATHER CONCERNS THIS
WEEKEND. WARM OVERNIGHT TEMPERATURES OF MORE THAN 70 DEGREES IN
LOWER NV VALLEYS WILL YIELD POOR RH RECOVERIES THROUGH SUNDAY
MORNING.
IN ADDITION, ISOLATED DRY THUNDERSTORMS ARE POSSIBLE TODAY AND
SUNDAY ALONG THE SIERRA FRONT AND EASTERN SIERRA OVER MONO/MINERAL
COUNTIES DUE TO FAST STORM MOTIONS OF 15-20KT. CHANCES FOR DRY
T-STORMS NEXT WEEK WILL BE LIMITED TO MONO/S LYON/MINERAL
COUNTIES FOR THE MOST PART, THOUGH LOCATION AND STORM MOTION
UNCERTAINTY INCREASES AS WE HEAD INTO MID-WEEK.
-JUSTIN
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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