150
FXUS65 KREV 190949
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
249 AM PDT SUN JUL 19 2026
KEY MESSAGES
* SEASONABLY WARM TEMPERATURES ARE FORECAST FOR THE REGION THROUGH
THIS WEEK.
* AREAS OF INCREASED CLOUD COVER PREVAIL TODAY WITH CHANCES FOR
ISOLATED SHOWERS AND THUNDERSTORMS BEGINNING NEAR THE EASTERN
SIERRA THIS AFTERNOON BEFORE SPREADING NORTHWARD GOING INTO THE
NIGHT.
* PERIODS OF MONSOONAL MOISTURE WILL KEEP SHOWER AND THUNDERSTORM
CHANCES WITH POTENTIAL FOR LOCALIZED HEAVY RAIN THIS WEEK. BEST
OVERALL STORM CHANCES FAVOR MONDAY AFTERNOON THROUGH WEDNESDAY.
DISCUSSION
FOR TODAY, FORECAST GUIDANCE DEPICTS A HIGH PRESSURE RIDGE CENTERED
OVER THE FOUR CORNERS REGION YIELDING A SOUTH-SOUTHWESTERLY FLOW
OVER THE CWA. THIS RIDGE IS PROJECTED TO STRENGTHEN ON MONDAY AND
TUESDAY, WHICH TURNS THE CWA'S UPPER FLOW MORE SOUTHERLY. ON
WEDNESDAY, THE HIGH PRESSURE CONTROLLING THE UPPER RIDGE TRAVELS
MORE TOWARDS OK/TX, WHICH THEN CHANGES THE CWA'S UPPER FLOW TO
SOUTHWESTERLY WITH LOW PRESSURE DEVELOPING OFF THE PACIFIC COAST.
WHILE FORECAST GUIDANCE DIVERGES A BIT FOR THE REST OF THE WEEK,
THE POPULAR SOLUTION APPEARS TO AT LEAST KEEP THE CWA UNDERNEATH
THE INFLUENCE OF THE RIDGE. WITH THIS PATTERN ALOFT, AREA HIGH
TEMPERATURES GENERALLY STAY NEAR THE SEASONAL NORMAL TEMPERATURES
FOR MID-JULY. W NV VALLEYS ARE FORECAST TO BE IN THE 90S THROUGH
THE WEEK WITH SOME PORTIONS SUCH AS LOVELOCK AND FALLON NEARING OR
EVEN REACHING THE CENTURY MARK. SIERRA COMMUNITIES EXPECT HIGHS
RANGING BETWEEN THE UPPER 70S AND THE 80S. THIS PATTERN THOUGH
WILL ALLOW FOR A GOOD AMOUNT OF OVERNIGHT CLOUD COVER THROUGH AT
LEAST THE FIRST HALF OF THE WEEK, WHICH WILL KEEP LOW TEMPERATURES
ABOUT 5-15 DEGREES ABOVE MID-JULY NORMALS.
THIS AFOREMENTIONED RIDGE PATTERN WILL BRING IN MONSOONAL MOISTURE
TO THE REGION STARTING TODAY WHICH CAN ALREADY BE SEEN MOVING
INTO THE SW CONUS IN THE LATEST IR WATER VAPOR SATELLITE IMAGERY.
WITH THIS MOISTURE, CLOUD COVER WILL INCREASE THROUGH THE DAY AND
CAUSE SHOWER AND THUNDERSTORM CHANCES WITHIN THE REGION. CAMS ARE
SHOWING A ~15% CHANCE FOR ISOLATED LIGHT SHOWERS THIS MORNING IN
NE CA DOWN TO AROUND THE TAHOE BASIN THAT EXPECT TO TAPER OFF BY
THE LATE MORNING. BUT IN THE AFTERNOON, MONO AND ALPINE COUNTIES
AS WELL AS ADJACENT PORTIONS OF NV BEGIN TO SEE A 25-50% CHANCE
FOR SHOWERS AND NON-SEVERE THUNDERSTORMS AROUND 1-2 PM PDT. GOING
INTO THE LATE AFTERNOON, CHANCES DIMINISH TO AROUND 25% AND SPREAD
INTO THE NORTH INCLUDING THE RENO-SPARKS AREA. SHOWER CHANCES FOR
THE REGION THEN LOWER EVEN MORE TO AROUND 15% OVERNIGHT BEFORE
ENDING EARLY MONDAY MORNING. THERE STILL IS POTENTIAL THAT THE
WIDESPREAD DEVELOPMENT OF CLOUDS WILL INHIBIT CONVECTION IN THE
EVENING AND OVERNIGHT HOURS FOLLOWING THE AFTERNOON THUNDERSTORMS
THAT COULD POP UP IN THE EASTERN SIERRA.
FOR MONDAY AND TUESDAY, MORE SHOWERS AND THUNDERSTORMS ARE EXPECTED
WITH MONSOONAL MOISTURE CONTINUING TO FLOW INTO THE REGION. MODELS
ARE CONTINUING TO SHOW PW VALUES EXCEEDING 1 INCH ON BOTH DAYS
WITH PORTIONS OF W NV SURPASSING 1.25 INCHES ON TUESDAY. THIS
MEANS THAT THUNDERSTORMS THAT DO DEVELOP WILL BE CAPABLE OF HEAVY
RAINFALL. EXPECTED STORM MOTION CONTINUES TO BE ON THE SLOWER
SIDE, SO THIS POINTS TO THE POTENTIAL FOR FLASH FLOODING TO OCCUR
WITHIN THE REGION. ON MONDAY, A ~50-70% CHANCE FOR SHOWERS AND
THUNDERSTORMS BEGINS ONCE AGAIN IN THE EASTERN SIERRA AND ADJACENT
PORTIONS OF NV IN THE AFTERNOON. THESE CHANCES LOWER A BIT TO
AROUND 40-60% AND ALSO SPREAD MORE INTO THE NV BASIN AND RANGE BY
THE EVENING WITH THE QUAD COUNTY AREA SEEING AROUND A 25% CHANCE.
PRECIPITATION CHANCES THEN MOSTLY TAPER OFF OVERNIGHT THOUGH
THERE STILL IS AROUND A 10- 15% CHANCE FOR A LINGERING SHOWER IN
PORTIONS OF W NV. ON TUESDAY, MORE WIDESPREAD SHOWER AND
THUNDERSTORM CHANCES (20-80% WITH THE HIGHER END CHANCES IN THE
EASTERN SIERRA) ARE CURRENTLY FORECAST. WITH THE AFOREMENTIONED
HEAVY RAINFALL POTENTIAL, THIS IS LOOKING RIGHT NOW TO BE THE MOST
PROBABLE DAY FOR FLASH FLOODING WITHIN THE AREA (JUST AHEAD OF
MONDAY IN THE UPCOMING DAYS). PLEASE CONTINUE TO MONITOR THE
FORECAST AS MORE DETAILS BECOME AVAILABLE IN CASE PREPARATIONS
NEED TO BE MADE FOR YOUR AREA.
DAILY SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE IN THE CWA
WEDNESDAY ONWARD THOUGH THEY DIMINISH EACH DAY AND ARE
CONSIDERABLY LESS THAN THE CHANCES SEEN EARLY WEEK (20-40% ON
WEDNESDAY AND UP TO AROUND 20% FOR THE REMAINING DAYS). THE
PRECIPITATION COVERAGE CURRENTLY IS FORECAST TO BE CONFINED
MOSTLY TO MONO COUNTY AND THE NV BASIN AND RANGE ON THESE DAYS.
HOWEVER, THERE IS SOME UNCERTAINTY IN THE EVOLUTION OF THE HIGH
PRESSURE RIDGE AS SOME MODELS DO SHOW IT RETROGRADING BACK TO OVER
THE FOUR CORNERS BY THE END OF THE WEEK. WILL CONTINUE TO MONITOR
THIS GOING FORWARD IN CASE TRENDS BEGIN TO SHOW MORE MONSOONAL
MOISTURE FLOWING INTO THE REGION LATER IN THE WEEK. -078
AVIATION
VFR CONDITIONS ARE CURRENTLY FORECAST FOR TODAY AND TONIGHT FOR ALL
AREA TAF SITES. MONSOONAL MOISTURE IS EXPECTED TO PUSH INTO THE
REGION STARTING TODAY ALLOWING FOR INCREASED MID-HIGH LEVEL CLOUD
COVER. MODELS ALSO ARE SHOWING SHOWER CHANCES TO BEGIN IN THE EASTERN
SIERRA AROUND 19/20-21Z THAT WILL SPREAD INTO THE SIERRA FRONT BY
19/23Z-20/00Z. SHOWER AND THUNDERSTORM CHANCES THEN EXPECT TO
INCREASE GOING INTO MONDAY AND TUESDAY WITHIN THE REGION BRINGING
POTENTIAL IMPACTS INCLUDING HEAVY RAINFALL, MORE FREQUENT LIGHTING,
AND OUTFLOW GUSTS OF 30+ KTS. SEASONABLY WARM DAYTIME HIGH TEMPERATURES
MAY CONTINUE DENSITY ALTITUDE CONCERNS THROUGH THE WEEK. -078
REV WATCHES/WARNINGS/ADVISORIES
NV...NONE.
CA...NONE.
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