445
FXUS65 KREV 202102
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
202 PM PDT SUN SEP 20 2026
KEY MESSAGES
* DRY AND MILD CONDITIONS PERSIST FOR THE REST OF TODAY.
* PRECIPITATION POTENTIAL RETURNS MONDAY, ESPECIALLY FOR MINERAL
COUNTY AND THE EASTERN SIERRA.
* PLAN ON INCREASED WINDS BY THURSDAY AND A RETURN OF PRECIPITATION
CHANCES BY FRIDAY.
DISCUSSION
THE LATEST RAP ANALYSIS OF THE UPPER AIR PATTERN SHOWS THE CWA
UNDERNEATH AN UPPER RIDGE WITH AN UPPER LOW OFF THE CA COAST THIS
AFTERNOON. GOING THROUGH THE REST OF THE DAY, MODELS SHOW THE
PACIFIC LOW PROGRESSING EAST TOWARD CA AND BEGINNING TO PUSH THE
RIDGE EASTWARD. CURRENT SATELLITE IMAGERY SHOWS PARTLY TO MOSTLY
CLOUDY SKIES ACROSS THE REGION, WHICH IS EXPECTED TO CONTINUE GOING
INTO THE NIGHT. THE MODEL CONSENSUS LOOKS TO FAVOR DRY CONDITIONS
THROUGH THE REST OF THE DAY. OVERNIGHT TEMPERATURES ARE FORECAST TO
BE SLIGHTLY HIGHER THAN LAST NIGHT'S WITH THE INCREASED CLOUD
COVER. LOW TEMPERATURES IN THE VALLEYS ARE FORECAST TO BE IN THE
50S WITH SIERRA COMMUNITIES IN THE 40S.
MODEL GUIDANCE THEN PROJECTS THE WESTERN LOW MOVING ACROSS CENTRAL
CA TOMORROW BEFORE OPENING INTO A TROUGH PASSING THROUGH NV ON
TUESDAY. WITH THE PROJECTED TRACK OF THIS FEATURE GOING THROUGH THE
SOUTHERN PORTIONS OF THE CWA, THE LATEST NBM GUIDANCE IS NOW GIVING
MINERAL COUNTY AND THE EASTERN SIERRA A ~20-40% CHANCE FOR SHOWERS
ON MONDAY AFTERNOON AND EVENING. THE LATEST RRFS CONTINUES TO
SHOW SOME ISOLATED SHOWER CHANCES (10-15% CHANCE) REACHING ACROSS
THE TAHOE REGION AND INTO LASSEN COUNTY, BUT NOT THE BEST
CONFIDENCE YET WITH THESE CHANCES AS THE HRRR STAYS DRY IN THIS
PORTION OF THE AREA. QPF PROJECTIONS STILL ARE RANGING UP TO
AROUND A FEW TENTHS OF AN INCH AT THE HIGHEST SIERRA ELEVATIONS.
SOME RUMBLES OF THUNDER COULD OCCUR WITHIN SHOWERS ON MONDAY, BUT
CHANCES ARE STILL ON THE LOW SIDE FOR NOW (<10%). ELSEWHERE, DRY
CONDITIONS WILL PERSIST TOMORROW. PRECIPITATION CHANCES TAPER OFF
TO THE EAST AROUND MIDNIGHT, LEAVING DRY CONDITIONS TO FOLLOW ON
TUESDAY AS TEMPERATURES CONTINUE A SLIGHT WARMING TREND.
FOR WEDNESDAY, MORE DRY WEATHER IS EXPECTED WITH DAYTIME HIGH
TEMPERATURES CLIMBING TO THE MIDDLE TO UPPER 80S RANGE IN THE W NV
VALLEYS AND THE LOWER TO UPPER 70S RANGE IN SIERRA COMMUNITIES.
WHILE SIMILAR TEMPERATURES ARE IN THE FORECAST FOR THURSDAY,
FORECAST ENSEMBLES SHOW A TROUGH MOVING INTO THE PACNW BY LATTER
HALF OF THE DAY. THIS FEATURE WILL ALLOW FOR WINDS TO INCREASE A
BIT ON THURSDAY AND FRIDAY (50-75% NBM PROBABILITY OF 30+ MPH
WINDS). PRECIPITATION CHANCES LOOK TO RETURN ON FRIDAY WITH A
POTENTIAL COLD FRONT PASSAGE, BUT MOSTLY FOR AREAS ALONG THE OR
BORDER WHICH CURRENTLY HAS A 15% CHANCE FOR SHOWERS. IF MODELS
BEGIN TO SHOW THE AFOREMENTIONED TROUGH MOVING MORE SOUTHWARD, THE
PRECIPITATION COVERAGE MAY ALSO SPREAD MORE SOUTH IN THE REGION.
WILL BE MONITORING HOW MODELS DEAL WITH THIS TROUGH GOING
FORWARD. OTHERWISE, COOLER TEMPERATURES ARE EXPECTED GOING INTO
THE WEEKEND WITH DRY CONDITIONS FAVORED. -078
AVIATION
VFR CONDITIONS ARE EXPECTED AT ALL TAF SITES TODAY AND TONIGHT WITH
PARTLY TO MOSTLY CLOUDY SKIES WITHIN THE REGION. WINDS WILL REMAIN
RELATIVELY LIGHT WITH AFTERNOON GUSTS UP TO AROUND 15 KTS. FORECAST
MODELS SHOW WINDS AT THE SIERRA CREST GUSTING UP TO AROUND 20 KTS
BETWEEN 06-12Z MONDAY WHICH MAY RESULT IN MINOR MOUNTAIN WAVE TURBULENCE
CONCERNS ALONG AND WEST OF THE SIERRA. PRECIPITATION CHANCES (20-40%)
RETURN TO MINERAL COUNTY AND THE EASTERN SIERRA BETWEEN 18Z MONDAY
AND 06Z TUESDAY, WITH A 10-15% CHANCE FOR ISOLATED SHOWERS ACROSS
TAHOE AND INTO NE CA DURING THE SAME TIME. -078
REV WATCHES/WARNINGS/ADVISORIES
NV...NONE.
CA...NONE.
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