206
FXUS65 KREV 271020
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
320 AM PDT THU AUG 27 2026
KEY MESSAGES
* BREEZY TO GUSTY WINDS CONTINUE TODAY, ALLOWING FOR ELEVATED TO
CRITICAL FIRE WEATHER CONDITIONS IN NORTHEASTERN CALIFORNIA AND
NORTHWESTERN NEVADA.
* ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE TODAY IN WESTERN
NEVADA AND THE SIERRA.
* A WEATHER SYSTEM ON FRIDAY BRINGS INCREASED CHANCES FOR SHOWERS
AND THUNDERSTORMS AND COOLER TEMPERATURES TO THE REGION.
DISCUSSION
FOR TODAY, MODEL GUIDANCE SHOWS THE CWA BETWEEN AN UPPER RIDGE OVER
THE SW CONUS AND AN PACNW UPPER LOW OVER THE COAST OF BC. THIS LOW
IS PROJECTED TO SLOWLY MAKE ITS WAY EASTWARD TODAY, CAUSING THE
SOUTHWESTERLY UPPER AIR FLOW OVER NE CA AND NW NV TO INCREASE A
BIT. THESE QUICKER WINDS EXPECT TO MIX DOWN IN THE AFTERNOON AND
ALLOW FOR SOUTHWESTERLY GUSTS UP TO AROUND 25-30 MPH (UP TO 35 MPH
POSSIBLE IN THESE AREAS. WITH DRY CONDITIONS PREVAILING HERE,
THERE WILL BE ELEVATED TO AREAS OF CRITICAL FIRE WEATHER TODAY
(SEE FIRE WEATHER SECTIONS FOR MORE INFORMATION). PLEASE PRACTICE
FIRE SAFETY AND REFRAIN FROM ACTIVITIES THAT MAY CAUSE SPARKS
TODAY.
WHILE THE AFOREMENTIONED PORTIONS OF THE CWA LOOK TO STAY MOSTLY
DRY, THE LATEST RUNS OF THE CAMS SHOW AROUND A 15-40% CHANCE FOR
ISOLATED SHOWERS TODAY FOR AREAS ALONG AND SOUTH OF I-80 MOSTLY
BETWEEN 2-10 PM WITH SOME CHANCES LINGERING IN THE NV BASIN AND
RANGE UNTIL MIDNIGHT. THERE ALSO LOOKS TO BE AROUND A 5-10% CHANCE
FOR A SHOWER TO CONTAIN LIGHTNING TODAY. FORECAST CAPE VALUES
LOOK TO BE AROUND 100-200 J/KG IN SOME AREAS IN THE SIERRA AND
SIERRA FRONT TODAY AND DCAPE VALUES STILL ARE OVER 1000 J/KG THIS
AFTERNOON, SO OUTFLOW WIND GUSTS UP TO AROUND 45-50 MPH COULD BE
POSSIBLE WITH STORMS ALONG WITH BRIEF PERIODS OF HEAVY RAINFALL.
GOING INTO FRIDAY, FORECAST GUIDANCE SHOWS THE UPPER LOW MAKING ITS
WAY ALONG THE CANADA/U.S. BORDER AND PUSHING THE INFLUENCE OF THE
UPPER RIDGE AWAY FROM THE CWA A BIT. THIS SETUP NOT ONLY LOOKS TO
PUSH SOME COOLER AIR IN FROM THE NORTH, BUT IT ALSO LOOKS TO PUMP
MORE MONSOONAL MOISTURE INTO THE REGION. AS SUCH, MODEL GUIDANCE IS
SHOWING IT TO BE A CLOUDY DAY WITH INCREASED CHANCES FOR
PRECIPITATION. THE LATEST RUN OF THE NBM IS SHOWING A 40-80% CHANCE
FOR WIDESPREAD SHOWERS THROUGH THE DAY IN THE REGION ON FRIDAY.
PW VALUES LOOK TO BE ON THE HIGHER SIDE (1+ INCHES), BUT THIS MAY
JUST ALLOW FOR THE INCREASED CLOUD COVER. QPF VALUES FOR FRIDAY
RANGE BETWEEN A TRACE AND UP TO AROUND 0.5 INCHES IN THE HIGHEST
PORTIONS OF THE SIERRA. WHILE THE INCREASED CLOUD COVER MAY
INHIBIT SOME AFTERNOON CONVECTION, THERE STILL LOOKS TO BE A
15-25% CHANCE FOR ISOLATED THUNDERSTORMS IN THE REGION. FORECAST
CAPE VALUES CURRENTLY REACH OVER 1000 J/KG IN THE NV BASIN AND
RANGE ON FRIDAY, SO THERE COULD BE SOME STRONG STORM POTENTIAL.
THE WPC EXCESSIVE RAINFALL OUTLOOK SHOWS A MARGINAL (5%) RISK FOR
EXCESSIVE RAINFALL FOR MOST OF THE CWA ON FRIDAY AS STORMS WILL BE
CAPABLE OF PERIODS OF HEAVY RAINFALL ONCE AGAIN. PLEASE WATCH FOR
FORECAST UPDATES AS THEY BECOME AVAILABLE, ESPECIALLY IF YOU PLAN
ON TRAVELING TO THE EVENTS IN BLACK ROCK DESERT. PRECIPITATION
CHANCES CURRENTLY LOOK TO TAPER OFF GOING INTO SATURDAY.
WITH COOLER AIR MOVING IN AND LESSER HEATING FROM THE EXPECTED
CLOUD COVER, DAYTIME HIGH TEMPERATURES ARE FORECAST TO BE AROUND
5-10 DEGREES LOWER ON FRIDAY WHEN COMPARED TO THE PRIOR DAYS IN
THE WEEK. THE NE CA AND W NV VALLEYS WILL HAVE HIGHS AROUND THE 80
DEGREE MARK WHILE SIERRA COMMUNITIES WILL BE IN THE UPPER 60S TO
MIDDLE 70S RANGE. AREA TEMPERATURES DO EXPECT TO REBOUND BY A FEW
DEGREES GOING THROUGH THE WEEKEND AND INTO NEXT WEEK. DRY
CONDITIONS LOOK TO BE ON TAP AT THE BEGINNING OF THE WEEK, BUT
THERE ARE SOME HINTS OF PRECIPITATION POSSIBLE BY THE MIDDLE OF
NEXT WEEK WITH ANOTHER SYSTEM. HOWEVER, FORECAST CONFIDENCE OUT
THIS FAR IS STILL QUITE LOW. -078
AVIATION
TAF SITES LOOK TO SEE MOSTLY VFR CONDITIONS TODAY AND TONIGHT. AREA
WINDS WILL GUST UP TO AROUND 20-25 KTS BETWEEN 27/20Z-28/04Z, WITH
PORTIONS CLOSER TO THE OR BORDER SEEING GUSTS UP TO AROUND 30 KTS.
FORECAST GUIDANCE SHOWS AROUND A 10-40% CHANCE FOR SHOWERS BETWEEN
27/20Z-28/06Z IN W NV AND THE SIERRA, WITH THE HIGHER END CHANCES IN
MONO COUNTY. IN ADDITION, THERE IS A 5-10% CHANCE FOR AN ISOLATED
THUNDERSTORM WITHIN THESE SHOWER CHANCES. NOT ANTICIPATING SUB-VFR
CONDITIONS TODAY DUE TO SHOWER AND STORM CHANCES, BUT WILL MONITOR
CONDITIONS AND AMEND TAFS IF GUIDANCE BEGINS SHOWING OTHERWISE. ON
FRIDAY, A COOLER WEATHER SYSTEM MOVES THROUGH THE REGION, BRINGING
INCREASED CLOUD COVER AND A MORE WIDESPREAD 40-80% CHANCE FOR
SHOWERS AND THUNDERSTORMS TO THE AREA. -078
FIRE WEATHER
ELEVATED TO AREAS OF CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED
AGAIN TODAY IN FAR NE CA AND FAR NW NV. SW WINDS GUSTING UP TO
25-30 MPH (ISOLATED POCKETS OF UP TO 35 MPH POSSIBLE IN WIND PRONE
AREAS) AND MINIMUM RH VALUES BETWEEN 8-20% ARE IN THE FORECAST IN
THE AFTERNOON FOR THESE AREAS. RH RECOVERIES IN THESE AREAS WILL
IMPROVE SLIGHTLY TO AROUND 35-50% ON THURSDAY NIGHT. ELSEWHERE,
THERE IS AROUND A 5-10% CHANCE FOR AN ISOLATED THUNDERSTORM
EMBEDDED WITHIN A 15-40% CHANCE OF SHOWERS THIS AFTERNOON. A
COOLER WEATHER SYSTEM ON FRIDAY BRINGS INCREASED CHANCES (40-80%)
FOR MORE WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS, WHICH WILL
REDUCE FIRE WEATHER CONCERNS FOR THE REGION. -078
REV WATCHES/WARNINGS/ADVISORIES
NV...NONE.
CA...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page