124
FXUS65 KREV 180943
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
243 AM PDT SAT JUL 18 2026
KEY MESSAGES
* INCREASED BREEZES AND LOW HUMIDITY WILL LEAD TO ELEVATED FIRE
WEATHER CONCERNS THIS AFTERNOON, ESPECIALLY FOR NORTHEAST
CALIFORNIA AND NORTHWEST NEVADA.
* SEASONABLY WARM AND MAINLY DRY CONDITIONS PREVAIL THROUGH THIS
WEEKEND WITH LOW CHANCES FOR ISOLATED SHOWERS AND THUNDERSTORMS
IN THE EASTERN SIERRA THIS AFTERNOON.
* PERIODS OF MONSOONAL MOISTURE RETURN NEXT WEEK, RENEWING CHANCES
FOR SHOWERS AND THUNDERSTORMS, WITH POTENTIAL FOR LOCALIZED HEAVY
RAIN.
DISCUSSION
FOR TODAY, MODEL GUIDANCE DEPICTS AN UPPER LOW OVER SOUTHERN BC
TRAVELING EASTWARD ACROSS SW CANADA WHILE OPENING UP INTO A
TROUGH. AS THIS HAPPENS, A HIGH PRESSURE RIDGE OVER THE ROCKIES IS
FORCED SOUTHWARD AND SPREADS A BIT MORE INTO THE WESTERN CONUS
OVERNIGHT. AT THE SURFACE, DRY CONDITIONS LOOK TO PERSIST WITH
AFTERNOON MINIMUM RELATIVE HUMIDITY VALUES GENERALLY AROUND OR
BELOW 15% IN NE CA AND W NV. THE LATEST NBM RUN ALSO HIGHLIGHTS
PORTIONS OF NE CA AND N. WASHOE COUNTY WITH AROUND A 30-50%
PROBABILITY OF SEEING GUSTS REACHING UP TO AROUND 30 MPH IN THE
AFTERNOON AND EARLY EVENING. WITH THESE INCREASED WINDS AND LOW RHS
EXPECTED, NE CA AND NW NV WILL SEE ELEVATED FIRE WEATHER CONCERNS
TODAY. PLEASE CONTINUE TO AVOID ACTIVITIES THAT CAN CAUSE SPARKS
IN THESE CONDITIONS.
WHILE MAINLY DRY CONDITIONS ARE EXPECTED TODAY, THE LATEST CAMS
DO SHOW MONO AND SOUTHERN ALPINE COUNTIES AS WELL AS ADJACENT
PORTIONS OF NV HAVING AROUND A 15% CHANCE FOR ISOLATED SHOWERS
THIS AFTERNOON DUE TO DIURNAL HEATING. RRFS CAPE VALUES IN THESE
AREAS REACH UP TO BETWEEN 100-200 J/KG, SO THERE IS SIMILAR CHANCE
FOR A FEW RUMBLES OF THUNDER WITHIN THESE SHOWERS THOUGH NOT
ANTICIPATING SEVERE WEATHER. REMEMBER: WHEN THUNDER ROARS, GO
INDOORS! IT'S ALSO POSSIBLE THAT RAIN MAY NOT REACH THE GROUND
FROM THESE SHOWERS TODAY WITH THE DRY AIR IN THE REGION. OVERNIGHT
TONIGHT INTO EARLY SUNDAY, CAMS ALSO SHOW ~15% CHANCES FOR
ISOLATED SHOWERS IN NE CA AND ADJACENT N. WASHOE COUNTY AS WELL.
AS FOR LATE SUNDAY AFTERNOON AND EVENING, THE HIGH PRESSURE OVER
THE FOUR CORNERS REGION ALLOWS SOME MOISTURE TO ENTER INTO THE
REGION CAUSING CLOUD COVER TO GRADUALLY INCREASE. THE LATEST CAM
RUNS ALSO HAVE LOW CHANCES (AROUND 10% AT MOST) FOR ADDITIONAL
LIGHT SHOWERS GENERALLY SOUTH OF US-50 THOUGH THESE CHANCES COULD
SPREAD INTO PORTIONS OF NE CA.
GOING THROUGH NEXT WEEK, MODEL GUIDANCE SHOWS THE UPPER RIDGE
RESIDING OVER THE WESTERN CONUS WITH HIGH PRESSURE BUILDING OVER THE
FOUR CORNERS REGION. THIS WILL ALLOW MONSOONAL MOISTURE TO FLOW BACK
INTO THE REGION, WHICH CAUSES DAILY PRECIPITATION CHANCES THROUGH
THE WEEK. WHEN LOOKING AT THE LATEST GFS PWAT VALUES, NE CA AND W NV
SEE AMOUNTS EXCEEDING 1" ON MONDAY AND TUESDAY WITH SOME PORTIONS OF
W NV REACHING UP TO AROUND 1.25". THIS SIGNALS THAT THUNDERSTORMS
ON THESE DAYS WILL HAVE THE POTENTIAL FOR HEAVY RAINFALL. FORECASTED
STORM MOTIONS ON THESE DAYS ALSO LOOKS TO BE ON THE SLOWER SIDE
AT THIS TIME, SO AREAS THAT SEE SHOWERS AND STORMS WITHIN REGION
MAY BE IN FOR POSSIBLE FLASH FLOODING CONCERNS. WILL BE
MONITORING THIS POTENTIAL GOING FORWARD TO SEE IF THESE TRENDS
CONTINUE, BUT PLEASE CONTINUE TO WATCH FOR THE LATEST FORECAST
UPDATES AS DETAILS BECOME MORE CERTAIN. ALSO: WHILE THE GFS DOES
SHOWS PWATS GRADUALLY TRENDING DOWNWARD ON WEDNESDAY THROUGH FRIDAY,
THEY STAY WITHIN THE RANGE (>0.6") WHERE STORMS COULD CONTAIN
HEAVY RAINFALL LEADING TO ADDITIONAL FLOODING CONCERNS. -078
AVIATION
VFR CONDITIONS ARE EXPECTED TODAY FOR ALL AREA TAF SITES. SIERRA
FRONT TERMINALS HAVE WESTERLY WINDS GUSTING UP TO AROUND 15-20 KTS
THIS AFTERNOON WITH KRNO POTENTIALLY SEEING GUSTS UP TO ~25 KTS
BETWEEN 18/02-04Z. AS FOR THE SIERRA TERMINALS, KTRK AND KMMH WILL
HAVE AFTERNOON WINDS GUSTING UP TO 20 KTS OUT OF THE SOUTHWEST-TO-
WEST WHILE LIGHTER WINDS ARE EXPECTED AT KTRK. THERE IS ALSO A
~15% CHANCE FOR ISOLATED SHOWERS AND STORMS IN THE EASTERN SIERRA
THIS AFTERNOON. HIGH TEMPERATURES AROUND MID-JULY SEASONAL NORMALS
ARE ALSO IN THE FORECAST WHICH MAY ALLOW FOR DENSITY ALTITUDE
CONCERNS GOING THROUGH THIS WEEKEND. -078
REV WATCHES/WARNINGS/ADVISORIES
NV...NONE.
CA...NONE.
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