861
FXUS65 KREV 200912
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
212 AM PDT THU AUG 20 2026
KEY MESSAGES
* DRY AND WARM CONDITIONS TODAY ACROSS THE REGION, WITH A
DOWNWARD TREND IN TEMPERATURES STARTING FRIDAY.
* INCREASING GUSTS ON FRIDAY AND SATURDAY LEAD TO ELEVATED TO
NEAR CRITICAL FIRE CONDITIONS FOR NORTHEAST CA AND NORTHWEST NV.
* ISOLATED SHOWER AND THUNDERSTORM POTENTIAL RETURNS FOR THE NV
BASIN AND RANGE, AND SOUTH OF US-50 FRIDAY INTO THE WEEKEND.
DISCUSSION
DRY AND WARM WEATHER CONTINUES TODAY WITH AFTERNOON HIGHS IN THE
UPPER 90S AND AROUND 100F. STARTING TOMORROW A GRADUAL COOLING
TREND STARTS AS AN UPPER TROUGH OFF THE WEST COAST STARTS TO PUSH
INLAND INTO THE PACNW. IT APPEARS THAT WE WILL BE IN A SIMILAR
ROUTINE FOR SEVERAL DAYS AT THE EDGE OF A LONGWAVE TROUGH. BY
EARLY NEXT WEEK, AFTERNOON HIGHS WILL BE IN THE UPPER 80S AND LOW
90S FOR WESTERN NV AND NORTHEAST CA, AND IN THE UPPER 70S TO LOW
80S FOR SIERRA COMMUNITIES.
THE FIRST PUSH OF THIS TROUGH WILL SEND THE UPPER HIGH TOWARDS
THE SOUTHERN PLAINS. IN TURN, OUR PRESSURE GRADIENT WILL TIGHTEN
AT THE SURFACE FRIDAY AND SATURDAY, RESULTING IN STRONGER WESTERLY
WINDS WITH GUSTS TO 30-35 MPH, WITH ISOLATED LOCATIONS POTENTIALLY
TO 40 MPH WITH A 10-50% CHANCE OF EXCEEDING 40 MPH ON SATURDAY.
THEREFORE, WE HAVE ELEVATED FIRE RISK ON FRIDAY, FOLLOWED BY
CRITICAL FIRE WEATHER ON SATURDAY FOR PORTIONS OF NE CA AND NW NV.
MORE ABOUT THIS IN THE FIRE SECTION BELOW.
THE BREAKING OF THE RIDGE ALSO ALLOWS FOR ADDITIONAL MOISTURE TO
MOVE NORTHWARD TOWARDS WESTERN NV AND THE EASTERN SIERRA. PW
INCREASES TO 0.8 TO 1 INCH FOR MONO/MINERAL/SRN LYON COUNTY AND
THE NV BASIN AND RANGE, THE REST OF THE AREA REMAINS IN THE
0.6-0.8 INCHES. THEREFORE, OUR BEST CHANCE FOR RAIN AND
THUNDERSTORMS WILL BE GENERALLY IN THE AFOREMENTIONED AREAS.
INSTABILITY REMAINS GENERALLY LOW WITH MUCAPE AT 100-500 J/KG AND
SHEAR AROUND 20-30 KTS. THUS, STORMS SHOULD BE MOSTLY ISOLATED.
SCATTERED STORMS HAVE THE BEST CHANCES OVER MINERAL ON SATURDAY
AND EASTERN CHURCHILL BOTH ON SATURDAY AND SUNDAY.
THE MONSOONAL MOISTURE PLUME MOVES EAST AGAIN BY TUESDAY AS
ANOTHER WAVE FROM THE WEST MOVES INLAND POTENTIALLY KEEPING COOLER
CONDITIONS ALONG WITH DRIER WEATHER.
-HC
AVIATION
VFR CONDITIONS PERSIST WITH AFTERNOON GUSTS TO 20 KTS. WINDS WILL
INCREASE ON FRIDAY, WITH AFTERNOON GUSTS TO 30 KTS. SHOWERS AND
STORMS MAY IMPACT KMMH/KHTH/KBAN ON FRIDAY, WITH A 10-20% CHANCE.
WINDS FURTHER INCREASE SATURDAY WITH GUSTS TO 35 KTS, ALONG WITH
INCREASING SHOWER AND STORM CHANCES.
-HC
FIRE WEATHER
ELEVATED FIRE RISK RETURNS ON FRIDAY WITH AN INCREASE OF WEST TO
SOUTHWESTERLY WINDS TO AROUND 30 MPH AND MIN RH AROUND 15-20% FOR
PORTIONS OF EASTERN LASSEN, THE SURPRISE VALLEY AND NORTHERN
WASHOE COUNTIES. CONDITIONS DETERIORATE TO CRITICAL BY SATURDAY
FOR THE SAME AREA WITH GUSTS TO 30-35 MPH AND A 40-80% CHANCE OF
GUSTS EXCEEDING 30 MPH, AND SIMILAR MIN RH COMPARED TO FRIDAY.
CRITICAL CONDITIONS MAY LAST FOR 3-6 HOURS BETWEEN SATURDAY
AFTERNOON AND EARLY EVENING. ISOLATED LOCATIONS IN NE CA AND NW NV
ON SATURDAY HAVE A 10-50% CHANCE OF GUSTS GREATER THAN 40 MPH.
FOR THESE REASONS, WE ARE HIGHLIGHTING OUR FIRE WEATHER PRODUCTS.
WE WILL DECIDE LATER TODAY IF A FIRE WEATHER WATCH IS NECESSARY
FOR THE AREA.
-HC
REV WATCHES/WARNINGS/ADVISORIES
NV...NONE.
CA...NONE.
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