615
FXUS65 KREV 061903
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
1203 PM PDT THU AUG 6 2026
KEY MESSAGES
* A PROLONGED PERIOD OF TRIPLE-DIGIT HEAT ACROSS WESTERN NV AND
EASTERN CA VALLEYS WILL CONTINUE THROUGH THIS WEEKEND.
* SMOKE AND HAZE FROM COULD BRING PERIODS OF DEGRADED AIR QUALITY
AT TIMES, ALTHOUGH COVERAGE IS EXPECTED TO DECREASE IN MOST
AREAS LATER TODAY THROUGH FRIDAY.
* DRY CONDITIONS PERSIST IN MOST AREAS, BUT LOW-END ISOLATED
AFTERNOON SHOWER AND THUNDER CHANCES RETURN FRIDAY THROUGH
EARLY NEXT WEEK FOR PARTS OF THE EASTERN SIERRA AND WESTERN NV.
DISCUSSION
ALL HEAT-RELATED ADVISORIES AND WARNINGS REMAIN IN PLACE THROUGH
THIS WEEKEND AS STRONG HIGH PRESSURE RIDGE PREVAILS ACROSS THE
SOUTHWEST US AND MUCH OF THE GREAT BASIN. THE HIGHEST DAYTIME
TEMPERATURES ARE EXPECTED ACROSS PERSHING AND CHURCHILL COUNTIES
WHERE WARMER DESERT VALLEYS COULD REACH OR SURPASS 105 DEGREES
FRIDAY THROUGH SUNDAY AFTERNOON. AN INCREASE IN MID-HIGH LEVEL
MOISTURE BRINGS INCREASED CLOUD COVER FROM THE EASTERN SIERRA INTO
MINERAL-LYON COUNTIES THIS AFTERNOON, THEN MORE OF THIS CLOUD
COVER EXPANDS NORTHWARD TO THE RENO-TAHOE REGION AT TIMES FRIDAY
AFTERNOON THROUGH SATURDAY. WHILE THESE CLOUDS MAY SHAVE OFF A
COUPLE DEGREES FROM AFTERNOON HIGHS IN THE HEAT ADVISORY AREAS, IT
WOULD ALSO LEAD TO LESS COOLING FOR FRIDAY AND SATURDAY NIGHTS,
WITH MORE AREAS REMAINING ABOVE 65 DEGREES AND WARMER VALLEY SITES
HOLDING ABOVE 70 DEGREES. FOR THOSE HEADING TO THE SIERRA
COMMUNITIES TO ESCAPE THE VALLEY HEAT, HIGHS NEAR OR ABOVE 90
DEGREES WILL STILL FEEL SUMMER-LIKE, ALTHOUGH NIGHTS WILL BE
NOTABLY COOLER.
THIS MOISTURE PUSH BRINGS AN INCREASE IN PW VALUES TO 0.6"-0.7"
THIS AFTERNOON INTO MONO-MINERAL-LYON COUNTIES, THEN CLIMBS TO
0.65"-0.85" FRIDAY AND SATURDAY AFTERNOONS IN THESE AREAS AND ALSO
EXPANDS NORTHWARD TO MORE OF WESTERN NV. LACK OF ADEQUATE FORCING
AND WARM AIR ALOFT SHOULD PREVENT ANYTHING MORE THAN CUMULUS
BUILDUPS, AND PERHAPS A FEW RAINDROPS REACHING THE GROUND THIS
AFTERNOON IN SOUTHERN MONO-MINERAL COUNTIES. FOR FRIDAY AFTERNOON,
A BIT MORE INSTABILITY AND UPPER LEVEL FORCING BRING INCREASED
SHOWER/ISOLATED THUNDER CHANCES (25-40%) TO THE EASTERN SIERRA,
WITH LOWER CHANCES (10-20%) EXTENDING NORTHWARD INTO FAR WESTERN
NV. RAINFALL LOOKS TO BE SPARSE UNLESS A CELL IS ABLE TO REDEVELOP
OVER THE SAME AREA OR ANCHOR TO A TERRAIN FEATURE, BUT WITH
DOWNDRAFT CAPE APPROACHING 1500 J/KG, STRONGER OUTFLOW GUSTS OF
40-50 MPH ARE WITHIN REASON.
A SIMILAR SCENARIO SETS UP EACH AFTERNOON THIS WEEKEND, ALTHOUGH
THE MAJORITY OF THE SHOWER/T-STORM CHANCES REMAIN LIMITED TO MONO,
MINERAL AND SOUTHERN LYON COUNTIES, WITH CHANCES DROPPING TO LESS
THAN 10% NORTH OF US-50.
AREAS OF HAZE AND SMOKE MAINLY FROM THE GANN FIRE IN CENTRAL CA
LINGER THROUGH THIS MORNING AND SHOULD LIFT AND DISPERSE THIS
AFTERNOON. WIND PATTERNS NEAR THE FIRE INDICATE LESS SPREAD OF
SMOKE INTO THE TAHOE-RENO REGIONS TONIGHT, ALTHOUGH LIGHTER HAZE
MAY LINGER ACROSS THE SIERRA AND WESTERN NV THROUGH FRIDAY.
HOWEVER, THE LATEST SMOKE TRAJECTORY GUIDANCE HINTS AT A RETURN
OF SMOKE FROM THE LARGER OREGON FIRES LATE TONIGHT ALONG THE OR
BORDER, THEN EXPANDING INTO NORTHWEST NV AND NORTHEAST CA LATE
FRIDAY NIGHT INTO SATURDAY. OVERALL WINDS FROM TODAY THROUGH
SATURDAY RESEMBLE A TYPICAL ZEPHYR-TYPE PATTERN WITH SW-W GUSTS
NEAR 25 MPH EACH AFTERNOON.
LOOKING TO NEXT WEEK FROM MONDAY ONWARD, THE HEAT WILL GRADUALLY
EASE WITH A FEW 100 DEGREE HIGHS LINGERING EARLY IN THE WEEK FOR
PARTS OF WEST CENTRAL NV, BUT BY MID-LATE WEEK HIGHS SETTLE INTO
NEAR SEASONAL AVERAGES OF LOWER-MID 90S FOR LOWER ELEVATIONS AND
LOWER 80S NEAR THE SIERRA. THIS COOLING IS LIKELY TO BE
ACCOMPANIED BY INCREASED SW-W WINDS ESPECIALLY MON-TUES WHICH
WOULD LEAD TO ELEVATED-LOCALLY CRITICAL FIRE WEATHER CONCERNS. DRY
AIR SPREAD ACROSS MOST OF THE REGION, BUT LINGERING MOISTURE AND
INSTABILITY IN MONO-MINERAL-SOUTHERN LYON COUNTIES COULD LEAD TO
AFTERNOON SHOWERS/T-STORMS IN THESE AREAS EACH DAY THROUGH
MIDWEEK. LATER NEXT WEEK, BLENDED GUIDANCE FAVORS A NORTHWARD
EXPANSION OF THESE SHOWER AND THUNDER CHANCES, BUT CONFIDENCE IS
LOWER ON THIS SCENARIO. MJD
AVIATION
* SW-W WIND GUSTS MAINLY 20-25 KT PREVAIL AT THE MAIN TERMINALS
EACH AFTERNOON THROUGH AT SATURDAY, GENERALLY RAMPING UP
BETWEEN 20-22Z AND DIMINISHING BY 03-05Z.
* VFR CONDITIONS CONTINUE THIS WEEK. LINGERING AREAS OF HAZE
AROUND THE MAIN TERMINALS MAY PRODUCE MINOR REDUCTIONS IN
SLANTWISE VISIBILITY, WITH THIS HAZE EXPECTED TO THIN OUT LATER
TODAY THROUGH FRIDAY.
* PROLONGED DAYTIME HEAT WILL RESULT IN DENSITY ALTITUDE CONCERNS
THROUGH THIS WEEKEND. MJD
REV WATCHES/WARNINGS/ADVISORIES
NV...HEAT ADVISORY UNTIL 8 AM PDT MONDAY NVZ001-003-005.
HEAT ADVISORY UNTIL 8 AM PDT FRIDAY NVZ004.
EXTREME HEAT WARNING FROM 8 AM FRIDAY TO 8 AM PDT MONDAY NVZ004.
CA...HEAT ADVISORY UNTIL 8 AM PDT MONDAY CAZ070-071.
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