660
FXUS65 KREV 021921
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
1221 PM PDT WED SEP 2 2026
KEY MESSAGES
* COOLER AND BREEZY CONDITIONS PERSIST THROUGH THURSDAY, WITH
WIDESPREAD GUSTS UP TO 30-40 MPH.
* RAIN CHANCES INCREASE FOR NE CA AND THE TAHOE BASIN LATE TONIGHT
INTO THURSDAY, WITH THE HIGHEST PROBABILITIES THURSDAY AFTERNOON
AND EVENING.
* UNCERTAINTY REMAINS HIGH REGARDING THE TRAJECTORY OF TS MARIE,
BUT AN INCREASE IN TROPICAL MOISTURE COULD BRING SHOWER AND
THUNDERSTORM CHANCES TO THE REGION SUNDAY INTO EARLY NEXT WEEK.
DISCUSSION
THE SYNOPTIC PATTERN FOR THE SHORT TERM IS DOMINATED BY AN UPPER-LEVEL
LOW DIGGING SOUTH FROM THE GULF OF ALASKA INTO THE PAC NW. THIS
TROUGHING OVER THE WEST COAST WILL CONTINUE TO USHER IN COOLER AIR
AND INCREASING MOISTURE INTO THE REGION, PARTICULARLY FOR
NORTHEAST CA AND FAR NORTHWEST NV. PERSISTENT TROUGHING AND A
SLOW-MOVING UPPER LOW OVER THE WEST COAST AND PACIFIC NORTHWEST
WILL BE THE MAIN PATTERN THROUGH EARLY NEXT WEEK. THIS PATTERN
WILL MAINTAIN COOLER THAN NORMAL TEMPERATURES ACROSS THE NORTHWEST
US, WHILE STOUT RIDGING ACROSS THE CENTRAL U.S. WILL LEAD TO
SOUTHWESTERLY FLOW USHERING IN TROPICAL MOISTURE ACROSS PARTS OF
THE SOUTHWEST AND INTERMOUNTAIN WEST.
FOR TODAY, BREEZY CONDITIONS CONTINUE WITH SOUTHWEST WINDS
GENERALLY 15-25 MPH GUSTING UP TO 30-45 MPH, ESPECIALLY IN WIND-
PRONE AREAS ALONG US-395 AND ACROSS LAKE SURFACES. AREAS OF
BLOWING DUST ARE POSSIBLE IN WESTERN NEVADA BASINS, INCLUDING NEAR
THE BLACK ROCK PLAYA AND CARSON SINK. HIGH TEMPERATURES WILL
REMAIN BELOW SEASONAL NORMS, GENERALLY IN THE LOW TO MID 60S FOR
SIERRA COMMUNITIES AND LOW TO MID 70S FOR LOWER VALLEYS.
TONIGHT, SHOWERS ARE EXPECTED TO DEVELOP ACROSS WESTERN LASSEN
COUNTY AND NORTHERN WASHOE COUNTY. NBM GUIDANCE SHOWS POPS
INCREASING TO 30-60% OVER THOSE AREAS OVERNIGHT. WINDS WILL
REMAIN BREEZY, ESPECIALLY OVER RIDGES, WITH GUSTS UP TO 40-45 MPH
POSSIBLE IN THE TAHOE BASIN AND LASSEN/E PLUMAS/E SIERRA.
OVERNIGHT LOWS WILL BE COOL, RANGING FROM THE LOW 30S IN THE
SIERRA TO MID-40S AND LOW 50S IN LOWER VALLEYS, WITH SOME SIERRA
COMMUNITIES FLIRTING WITH NEAR-FREEZING TEMPERATURES.
THURSDAY WILL BE THE MAIN PERIOD FOR PRECIPITATION. SHOWERS ARE
EXPECTED TO MOVE FARTHER EAST THURSDAY AFTERNOON, INTO THE TAHOE
BASIN AND SIERRA FRONT WITH POPS PEAKING AT 80-90% FOR LASSEN
COUNTY AND NW NV, 30-60% FOR THE TAHOE BASIN, AND 15% ALONG THE
SIERRA FRONT. BASED ON THE TRAJECTORY OF THE SYSTEM, THE SIERRA
FRONT LOOKS TO BE HEAVILY SHADOWED, SO ANY RAIN THAT MAKES IT OVER
THE SIERRA CREST WILL BE LIGHT. PRECIPITATION AMOUNTS RANGE FROM
A TRACE ALONG THE SIERRA FRONT, 0.10" AROUND THE TAHOE BASIN,
0.40-0.50" AROUND PORTOLA AND SUSANVILLE, AND UPWARDS OF AN INCH
ALONG THE SIERRA CREST. ISOLATED THUNDER CANNOT BE RULED OUT,
THOUGH INSTABILITY IS EXPECTED TO BE LIMITED. BREEZY CONDITIONS
WILL CONTINUE WITH SW WINDS 15-25 MPH AND GUSTS 30-40 MPH,
ESPECIALLY IN THE AFTERNOON. THE LAKE WIND ADVISORY CONTINUES
THROUGH 11 PM PDT THURSDAY.
BY FRIDAY, LINGERING SHOWERS ARE POSSIBLE IN THE NORTHERN SIERRA AND
NE CA EARLY FRIDAY MORNING, THEN CONDITIONS WILL QUICKLY DRY OUT
AS THE TROUGH MOVES EAST. MOSTLY CLEAR SKIES AND MILDER
TEMPERATURES ARE EXPECTED. WINDS WILL DIMINISH COMPARED TO
PREVIOUS DAYS, GENERALLY 10-15 MPH WITH GUSTS UP TO 30 MPH. HIGHS
WILL BE SIMILAR TO THURSDAY.
LOOKING AHEAD TO SUNDAY, INCREASING MOISTURE FROM THE SOUTH,
POTENTIALLY LINKED TO TROPICAL STORM MARIE, WILL BEGIN TO IMPACT
THE REGION. THE EXACT TRACK OF TROPICAL STORM MARIE REMAINS HIGHLY
UNCERTAIN, WITH MODELS GRAVITATING TOWARDS TWO SOLUTIONS: ONE
KEEPING THE STORM OFFSHORE, AND ANOTHER BRINGING IT NORTH TOWARDS
NORTHERN CALIFORNIA. EVEN IF THE LOW STAYS OFFSHORE,
SOUTHWESTERLY FLOW MAY PULL A DECENT AMOUNT OF MOISTURE INLAND.
WHILE CONFIDENCE IN SIGNIFICANT RAINFALL REMAINS LOW, THE
POTENTIAL FOR ISOLATED SHOWERS EXISTS FOR SUNDAY AND LABOR DAY.
CONDITIONS ARE EXPECTED TO DRY OUT AND WARM UP FURTHER BY TUESDAY
AS THE TROPICAL MOISTURE INFLUENCE WANES AND RIDGING STRENGTHENS.
-JUSTIN
AVIATION
VFR CONDITIONS CONTINUE TODAY, ALTHOUGH INCREASED WINDS ARE
EXPECTED AGAIN TODAY. GUSTS UP TO 35KT THIS AFTERNOON AND EVENING,
WITH LLWS AND MOUNTAIN WAVE TURBULENCE LIKELY. BLDU MAY BE SEEN
ACROSS WESTERN NV TODAY TOO, ESPECIALLY FOR AIRFIELD OPERATIONS
AT THE BLACK ROCK DESERT.
RAIN SHOWERS WILL START TO MOVE INTO FAR NORTHEAST CA AND FAR
NORTHWEST NV TONIGHT INTO THURSDAY MORNING, KEEPING ALL TERMINALS
VFR. BUT BY 19Z THURSDAY, THE SHOWERS WILL HAVE MOVED WELL INTO
THE SIERRA CREST AND TAHOE BASIN, POTENTIALLY PUSHING FLIGHT RULES
INTO MVFR-IFR FOR TRK AND TVL. RNO/CXP/MEV WILL BE HEAVILY
SHADOWED THURSDAY, MAINTAINING VFR, THOUGH A STRAY LIGHT SHOWER
CANNOT BE RULED OUT.
-JUSTIN
REV WATCHES/WARNINGS/ADVISORIES
NV...LAKE WIND ADVISORY UNTIL 11 PM PDT THURSDAY NVZ002>004.
CA...LAKE WIND ADVISORY UNTIL 11 PM PDT THURSDAY CAZ071>073.
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