082
FXUS65 KREV 282138
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
238 PM PDT MON JUL 28 2025
KEY MESSAGES
* AREAS OF SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED THROUGH THE
AFTERNOON AND ENDING IN THE EVENING.
* THUNDERSTORM ACTIVITY INCREASES TUESDAY AND WEDNESDAY, POSING A
RISK OF HEAVY RAIN AND FLOODING, GUSTY OUTFLOW WINDS, SMALL HAIL,
AND FREQUENT LIGHTNING.
* A DRYING TREND WILL LIMIT THUNDERSTORMS AFTER WEDNESDAY WITH
INCREASING BREEZES POSSIBLE OVER THE WEEKEND.
DISCUSSION
WEAK LOW PRESSURE IS LIFTING THROUGH NORTHERN CALIFORNIA PER 19Z
MOISTURE-CHANNEL IMAGERY AND WILL ASSIST IN SHOWER AND THUNDERSTORM
DEVELOPMENT THIS AFTERNOON. COVERAGE WILL BE LIMITED TODAY -- EVEN
MORE SO THAN YESTERDAY -- WITH GREATEST LIKELIHOOD FAVORING LASSEN
COUNTY, THE SURPRISE VALLEY INTO FAR N WASHOE COUNTY, AND FROM THE
QUAD COUNTIES TO THE US-95 CORRIDOR. SHOWERS AND STORMS MAY DEVELOP
ALONG THE SIERRA NORTH OF TAHOE, BUT ODDS OF THIS OCCURRING ARE
LOWER. OTHERWISE, IT'LL TAKE WELL-PLACED OUTFLOWS TO INITIATE STORMS
AWAY FROM THESE AREAS. THUNDERSTORMS WILL BE CAPABLE BRIEF HEAVY
DOWNPOURS, GUSTY OUTFLOW WINDS AND BLOWING DUST NEAR DESERT SINKS
AND PLAYAS, SMALL HAIL, AND LIGHTNING.
THUNDERSTORM ACTIVITY TRENDS UPWARD TUESDAY AND WEDNESDAY AS A
BETTER DEFINED LOW PRESSURE AREA PIVOTS THROUGH THE REGION. GREATER
INSTABILITY COUPLED WITH RICH MOISTURE ALOFT WILL INCREASE CHANCES
OF STORMS TO 20-40% AND 30-60% TUESDAY AND WEDNESDAY AFTERNOONS,
RESPECTIVELY. NE CALIFORNIA AND NW NEVADA WILL CONTINUE TO BE THE
MOST FAVORABLE AREAS, INCLUDING TAHOE COMMUNITIES AND THE GREATER
RENO-CARSON-MINDEN AREA. GUIDANCE REMAINS KEEN ON THE PROSPECT OF
NOCTURNAL SHOWERS AND STORMS FROM THE TAHOE BASIN NORTHWARD TUESDAY
NIGHT INTO WEDNESDAY MORNING, WHICH CORRESPONDS TO WHEN THE LOW
PRESSURE MOVES OVERHEAD. POTENTIAL IMPACTS ARE THE USUAL SUSPECTS --
STRONG OUTFLOWS, SMALL HAIL, LIGHTNING AND NEW FIRE STARTS, BLOWING
DUST -- BUT HEAVY RAIN AND FLASH FLOODING IS POSSIBLE GIVEN ABNORMAL
MOISTURE ALOFT. NEEDLESS TO SAY, EXPECT MORE STORMY WEATHER THROUGH
MIDWEEK.
MOISTURE SCOURS OUT IN THE WAKE OF THE LOW PASSAGE, REDUCING
THUNDERSTORM CHANCES AND COVERAGE AFTER WEDNESDAY. THERE IS STILL
THE POTENTIAL FOR INCREASED AFTERNOON BREEZES AND ELEVATED FIRE
CONCERNS THIS WEEKEND INTO EARLY NEXT WEEK, BUT CONFIDENCE REMAINS
LOW ON TIMING/MAGNITUDE.
-SALAS
AVIATION
* VFR CONDITIONS WILL GIVE WAY TO MVFR FOR SOME TERMINALS. CLOUDS
WILL CONTINUE TO DEVELOP AS STORMS ARRIVE ONCE AGAIN FOR THIS
AFTERNOON. CHANCES ARE GREATEST FOR KCXP AND KMEV (20-25%
CHANCE), WHILE KTRK, KRNO AND KTVL HAVE LOWER CHANCES (10-15%).
KSVE MAY SEE SHOWERS INITIATE NEARBY THEN MOVE NORTHWARD INTO
THE AFTERNOON AND EVENING. GUSTY OUTFLOW WINDS, SMALL HAIL,
HEAVY RAINS AND FREQUENT LIGHTNING ARE POSSIBLE AS WELL AS
TERRAIN OBSCURATION IN THE VICINITY OF ONGOING STORMS.
* SHOWERS AND STORMS RETURN EACH DAY THIS WEEK FOR MUCH OF THE
REGION, WITH THE LATER WEEK STORMS FIRING NEAR THE OREGON BORDER.
HRICH
FIRE WEATHER
THUNDERSTORM COVERAGE AND LIGHTNING DENSITY INCREASES TUESDAY AND
WEDNESDAY, ELEVATING THE POTENTIAL FOR NEW IGNITIONS REGIONALLY.
HOWEVER, THERE ARE COMPETING FACTORS THAT LIMITS CONFIDENCE IN THE
OVERALL LIGHTNING THREAT FOR MIDWEEK. ABUNDANT LIGHTNING IS BECOMING
MORE PROBABLE EACH AFTERNOON, PARTICULARLY IN NORTHEAST CALIFORNIA
AND NEAR THE OREGON BORDER WHERE THUNDERSTORM COVERAGE IS FAVORED TO
BE GREATEST. STORM MOTIONS WILL ALSO BE MODERATE, REDUCING THE
RESIDENCE TIME OF RAIN CORES OVER ANY LIGHTNING START. TO MAKE
MATTERS MORE COMPLICATED, THERE IS THE POSSIBILITY OF NOCTURNAL
LIGHTNING TUESDAY NIGHT INTO WEDNESDAY MORNING FROM THE TAHOE BASIN
NORTHWARD AS THE LOW PASSES OVERHEAD.
WITH ALL THAT BEING SAID, THUNDERSTORMS WILL TREND ON THE WETTER
SIDE OWING TO RICH MOISTURE ALOFT. FURTHERMORE, THE AREAS NEAR THE
OREGON BORDER HAVE RECEIVED CONSIDERABLE RAINFALL OVER THE LAST
SEVERAL DAYS, KEEPING FUELS SATURATED. THE MAIN TAKEAWAY IS THAT
INCREASING LIGHTNING PRODUCTION FROM WETTER THUNDERSTORMS IS
EXPECTED TUESDAY AND WEDNESDAY, AND MAY RESULT IN NEW IGNITIONS AWAY
FROM RAIN CORES.
-SALAS
REV WATCHES/WARNINGS/ADVISORIES
NV...NONE.
CA...NONE.
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