146
FXUS65 KREV 200921
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
221 AM PDT MON OCT 20 2025
KEY MESSAGES
* DRY AND MILD WEATHER WILL PREVAIL MUCH OF THIS WEEK WITH A CHANCE
OF RAIN AND HIGH ELEVATION SNOW SOUTH OF HIGHWAY 50 ON WEDNESDAY.
* AN ATMOSPHERIC RIVER EVENT MAY BRING PERIODS OF STRONG WINDS,
VALLEY RAIN, AND HEAVY SIERRA SNOW FRIDAY THROUGH SUNDAY, BUT
CONFIDENCE REMAINS LOW.
DISCUSSION
DRY AND MILD WEATHER IS IN STORE FOR MUCH OF THIS WEEK, OWING TO A
PREVALENT RIDGING PATTERN ACROSS THE WESTERN STATES. HOWEVER,
DISCRETE LOW PRESSURE WILL TRAVERSE SOUTHERN CA/NV ON WEDNESDAY AND
INCREASE SHOWER POTENTIAL AS IT DOES SO. GIVEN THAT THE LOW WILL
PASS TO OUR SOUTH, THE GREATEST POTENTIAL FOR SHOWERS EXIST SOUTH OF
US-50 WHERE ODDS ARE 10% OR GREATER. A CORRIDOR OF GREATER ODDS (20-
40%) DOES EXIST IN ALPINE AND MONO COUNTIES WHERE THERE MAY BE JUST
ENOUGH INSTABILITY TO SUPPORT HEAVIER SHOWERS OR PERHAPS AN ISOLATED
THUNDERSTORM WEDNESDAY AFTERNOON. ELSEWHERE, DRY CONDITIONS WILL
PERSIST WITH MINOR COOLING ON WEDNESDAY.
WE CONTINUE TO MONITOR THE POTENTIAL FOR AN ATMOSPHERIC RIVER STORM
TO IMPACT THE REGION FRIDAY THROUGH THE WEEKEND. THERE CONTINUES TO
BE MUCH UNCERTAINTY IN HOW THIS STORM UNFOLDS AS GUIDANCE OFFERS A
WIDE RANGE OF OUTCOMES. THE LATEST TREND HAS BEEN TO KEEP THE STORM
TRACK FARTHER NORTH, WHICH WOULD LIMIT RAIN AND SNOW TOTALS WITH
SOUTHERN EXTENT AND KEEP THE REGION ON THE WARMER SIDE OF THE STORM
-- RESULTING IN HIGHER SNOW LEVELS AND REDUCING SNOW TOTALS AWAY
FROM THE HIGHEST TERRAIN. AGAIN, THAT'S JUST THE LATEST TREND IN
GUIDANCE AND ADDITIONAL CHANGES ARE PROBABLE OVER THE NEXT SEVERAL
DAYS. AS WE KEEP ADVISING, NOW IT IS A GOOD TIME TO TAKE YOUR WINTER
SAFETY PRECAUTIONS AND FREQUENTLY CHECK THE LATEST FORECAST FOR THE
MOST UP TO DATE INFORMATION.
-SALAS
AVIATION
FZFG MAY DEVELOP AT KTRK BETWEEN 09Z AND 16Z THIS MORNING, LOWERING
CIGS/VIS TO IFR/LIFR CONDITIONS. OTHERWISE, VFR CONDITIONS AND LIGHT
BREEZES PREVAIL TODAY AS HIGH PRESSURE OVERSPREADS THE REGION.
-SALAS
REV WATCHES/WARNINGS/ADVISORIES
NV...NONE.
CA...NONE.
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