654
FXUS65 KREV 191913
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
1213 PM PDT SUN JUL 19 2026
KEY MESSAGES
* AFTERNOON SHOWER AND THUNDERSTORM CHANCES EACH DAY THIS WEEK,
BECOMING WIDER IN AREAL COVERAGE THROUGH MIDWEEK.
* ABUNDANT MOISTURE AND SLOWER STORM MOTIONS WILL INTRODUCE FLASH
FLOODING FROM HEAVY RAIN AS THE MAIN CONCERN.
* UNCERTAINTY LATER THIS WEEK INTO NEXT WEEKEND ON WHETHER THE
MONSOONAL PATTERN WILL PERSIST OR IF DRIER CONDITIONS EMERGE.
DISCUSSION
LIGHT SHOWERS EARLIER THIS MORNING HAVE PROGRESSED OUT OF THE
AREA, LEAVING CLEARING SKIES BEHIND, PROVIDING AMPLE DAYTIME
HEATING TO GET STORMS FIRING TODAY. SOUTHERLY FLOW WILL ALLOW FOR
A SOUTH TO NORTH PROPAGATION OF STORMS WITH SHOWERS AND
THUNDERSTORMS INITIALLY DEVELOPING ALONG THE SIERRA OF MONO COUNTY
TODAY (30-50% CHANCE). STORMS ARE EXPECTED TO TRACK NORTHWARD
INTO THE SIERRA FRONT (CHANCES DIMINISH TO ~25%). THE 12Z SOUNDING
OUT OF NWS RENO THIS MORNING RECORDED A PWAT OF 0.9", WHICH IS
WELL ABOVE THE 90TH PERCENTILE FOR TODAY'S SOUNDING CLIMATOLOGY.
THE MEAN WIND IN THE BULK OF THE PROFILE TOPPED OUT AT ABOUT 30
KTS, WHICH HINTS AT FASTER STORM MOTIONS. SO, TO GET ANY FLOODING
RIGHT NOW, WE WOULD NEED TRAINING STORMS. HOWEVER, THE DECENT WIND
SPEEDS AT THE LCL/LFC LAYER INDICATE THAT STORMS TODAY MAY BECOME
TILTED (REDUCES THE POTENTIAL FOR HAIL DEVELOPMENT), RESULTING IN
A SIMILAR SETUP TO LAST MONDAY/TUESDAY, WHICH PRODUCED LOCALIZED
FLOODING CONCERNS.
SHOWERS ARE EXPECTED TO CONTINUE INTO NE CA AND NORTHERN WASHOE
COUNTY AFTER SUNSET. THUNDER CHANCES FOR THIS AREA DECREASE TO
ABOUT 15% FOR THE OVERNIGHT PERIOD. CAM GUIDANCE PLACES SOME LIGHT
SHOWERS AROUND THE TAHOE BASIN TONIGHT, TOO, THOUGH CONFIDENCE ON
THAT MATERIALIZING REMAINS LOW.
MONDAY, CAM GUIDANCE STARTS CONVECTION ONCE AGAIN IN MONO COUNTY
BUT WITH A MORE SOUTHWESTERLY FLOW, STORMS ARE TO PUSH INTO
MINERAL/S LYON COUNTIES BEFORE CONTINUING INTO THE BASIN AND RANGE
SOUTH OF I-80. MODEL PWATS RANGE FROM 0.8-1.1" AND WITH SLOWER
STORM MOTIONS FORECAST, FLASH FLOODING QUICKLY BECOMES THE
CONCERN. AS SUCH, A FLASH FLOOD WATCH IS IN EFFECT FOR THE
AFOREMENTIONED COUNTIES MONDAY AFTERNOON THROUGH MONDAY EVENING.
ALSO, SOME OF THE CAM/HIGHER RESOLUTION GUIDANCE INTRODUCES A
LOWER-END CHANCE FOR NARROW SHOWER BANDS WITH EMBEDDED LIGHTING
IN PARTS OF NORTHEAST CA MONDAY AFTERNOON-EVENING.
TUESDAY, WE SEE LARGER AREAS OF DIFFLUENCE ALOFT ASSOCIATED WITH
TYPICAL CONVECTION INITIATION TIME. CAPE VALUES ARE PUSHING 1000
J/KG WITH PWATS TOPPING OUT AT 1-1.2". WIDESPREAD CONVECTION WILL
BE THE NAME OF THE GAME WITH STORMS ONCE AGAIN DEVELOPING IN MONO
COUNTY BEFORE PUSHING NORTHWARD. STORM MOTIONS REMAIN SLOW AND
WITH THE ABUNDANCE IN MONSOONAL MOISTURE, FLOODING IS ONCE AGAIN A
CONCERN. MAKE SURE YOU HAVE MULTIPLE WAYS TO RECEIVE WEATHER
WARNINGS AND NEVER DRIVE THROUGH FLOODED ROADWAYS!
MODEL GUIDANCE IS A BIT MIXED FOR LATER THIS WEEK AND NEXT
WEEKEND WITH THE FOUR CORNERS HIGH PROPAGATING CLOSER TO TEXAS,
WHICH WOULD REDUCE STORM CHANCES PAST WEDNESDAY. HOWEVER, SOME
MODELS HAVE THE HIGH RETROGRADING BACK TOWARDS THE FOUR CORNERS BY
THE END OF THE WEEK, WHICH IN TURN INCREASES STORM CHANCES. AS OF
NOW, THE FORECAST REMAINS ON TRACK WITH DAILY CHANCES FOR SHOWERS
AND THUNDERSTORMS MAINLY IN WEST CENTRAL NV ALONG AND EAST
OF US-95 AND SOUTHWARD TO MONO COUNTY, THOUGH UNCERTAINTY IN THE
INTENSITY AND AREAL COVERAGE OF STORMS REMAINS.
-GIRALTE
AVIATION
VFR CONDITIONS WILL PREVAIL FOR MOST OF THE PERIOD TODAY. THE
EXCEPTION WILL BE THIS AFTERNOON FROM ROUGHLY 22-03Z WHEN SHOWERS
AND THUNDERSTORMS ARE EXPECTED TO IMPACT FIRST KMMH AND THEN
KRNO/KCXP/KMEV. BRIEF PERIODS OF MVFR CONDITIONS LIKELY DUE TO
LOWER CIGS/VIS FROM HEAVY RAIN. VICINITY SHOWERS LIKELY FOR
KTRK/KTVL FOR A SIMILAR TIME FRAME, WHICH WILL ALLOW FOR MOUNTAIN
OBSCURATIONS AT ALL TERMINALS. LIGHT SHOWERS MAY DEVELOP OVER
KTRK/KTVL LATE TONIGHT, THOUGH CONFIDENCE REMAINS LOW. IF THESE
SHOWERS DO DEVELOP, THE MAIN TERMINAL IMPACT WOULD BE LIGHT RAIN
AND LOWER CIGS.
ANOTHER ROUND OF SHOWERS/T-STORMS IS EXPECTED MONDAY AFTERNOON-
EARLY EVENING, WITH BEST CHANCES (UP TO 50%) AT KMMH AND LESSER
CHANCES (10-20%) FOR THE WESTERN NV SITES (KRNO/KCXP/KMEV).
-GIRALTE
REV WATCHES/WARNINGS/ADVISORIES
NV...FLOOD WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING NVZ001.
CA...FLOOD WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING CAZ073.
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