226
FXUS65 KVEF 181853
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1153 AM PDT THU SEP 18 2025
KEY MESSAGES
* INCREASING TROPICAL MOISTURE WILL MOVE INTO THE REGION TODAY AND
FRIDAY, BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS. LOCALLY
HEAVY RAIN AND HIGH RAINFALL RATES WILL LEAD TO AN INCREASED RISK
OF FLASH FLOODING, ESPECIALLY OVER SAN BERNARDINO COUNTY TODAY.
* SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL LINGER THROUGH
THE WEEKEND, WITH MORE UNCERTAINTY NEXT WEEK AS ADDITIONAL
TROPICAL MOISTURE TRIES TO GET PULLED NORTHWARD.
DISCUSSION
THROUGH WEDNESDAY.
A BROAD AREA OF SHOWERS AND THUNDERSTORMS CONTINUES ACROSS SOUTHERN
INYO, EASTERN/CENTRAL SAN BERNARDINO, AND SOUTHERN MOHAVE
COUNTIES. THIS ACTIVITY WILL PUSH NORTHWARD THROUGHOUT THE
AFTERNOON, LIKELY FIZZLING OUT THIS EVENING AS IT REACHES OUR
SOUTHERN GREAT BASIN ZONES. BEHIND IT, MORE ROBUST THUNDERSTORM
DEVELOPMENT IS ANTICIPATED THE CLEAR SLOT PUNCHES IN. SOME OF THIS
DEVELOPMENT IS ALREADY BEING SEEN ACROSS FAR SOUTHERN SAN
BERNARDINO COUNTY. IT IS THIS ACTIVITY THAT IS THE MAIN FLASH
FLOODING AND SEVERE WIND CONCERN. THE EXTENT AND LONGEVITY OF THE
SECONDARY CONVECTION IS A BIT UNCERTAIN, BUT IT IS POSSIBLE THAT
THIS ACTIVITY LASTS WELL INTO THE EVENING, BRINGING A FLASH FLOOD
AND SEVERE THREAT TO SOUTHEAST INYO, SOUTHERN NYE, CLARK, AND
MOHAVE COUNTIES. CONVECTION SHOULD BEGIN TO WANE LATE TONIGHT AS
IT DRIFTS NORTHWARD. TOMORROW, SHOWERS AND STORMS WILL BE LESS
WIDESPREAD THAN TODAY, AND LARGELY FOCUSED IN SOUTHERN NEVADA AND
NORTHWESTERN ARIZONA. STORMS WILL CONTINUE TO POSE AN LOCALIZED
FLASH FLOOD AND GUSTY WIND THREAT.
AS MOISTURE AND UPPER-LEVEL SUPPORT DECREASE OVER THE WEEKEND,
CONVECTION IS FORECAST TO BECOME EVEN MORE ISOLATED AND DIURNALLY-
DRIVEN. THE REDUCTION IN MOISTURE/CLOUDS WILL ALLOW TEMPERATURES TO
WARM NEAR SEASONABLE VALUES. THESE CONDITIONS PERSIST THROUGH THE
MIDDLE OF NEXT WEEK AS WE WAIT TO SEE HOW THE NEXT TROPICAL REMNANTS
INTERACT WITH MID-LATITUDE FLOW. CURRENTLY, THE MOST LIKELY SCENARIO
APPEARS TO BE DRIER AND WARMER CONDITIONS, BUT SOME GUIDANCE DOES
BRING THE MOISTURE INTO OUR AREA, RESULTING IN ANOTHER ROUND OF
SHOWERS AND STORMS AROUND MID-WEEK.
AVIATION...FOR HARRY REID...FOR THE 18Z FORECAST PACKAGE
THE
EXPECTATION FOR TODAY IS AN INITIAL ROUND OF SHOWERS WITH A FEW
RUMBLES OF THUNDER POSSIBLE BETWEEN 19Z AND 01Z. AS THIS ACTIVITY
MOVES IN, ANTICIPATING A PUSH OF BREEZY SOUTH-SOUTHWEST WINDS
FOLLOWED BY A RETURN TO LIGHT WINDS ONCE SHOWERS/STORMS GET
ESTABLISHED IN THE VICINITY. DURING THE EVENING HOURS, UNCERTAINTY
GROWS AS PERIODS OF VICINITY STORMS ARE POSSIBLE THROUGH 07Z-09Z.
THESE STORMS HAVE THE POTENTIAL TO MOVE INTO THE VALLEY AND PRODUCE
GUSTY, ERRATIC WINDS, BUT FORECAST CONFIDENCE IS LOW. LIGHT WINDS
PERSIST THROUGH THE NIGHT, RETURNING TO A MORE TYPICAL PATTERN
TOMORROW MORNING. ANOTHER ROUND OF VICINITY CONVECTION IS EXPECTED
FRIDAY AFTERNOON. CIGS LARGELY REMAIN AT OR ABOVE 10KFT, BUT MAY DIP
DOWN TO ~8KFT DURING ANY PRECIPITATION.
FOR THE REST OF SOUTHERN NEVADA, NORTHWESTERN ARIZONA AND
SOUTHEASTERN CALIFORNIA...FOR THE 18Z FORECAST PACKAGE...FAIRLY
WIDESPREAD CONVECTION CONTINUES ACROSS EASTERN/CENTRAL SAN
BERNARDINO COUNTY AND SOUTHERN MOHAVE COUNTY THIS MORNING. THIS
ACTIVITY WILL PUSH NORTHWARD INTO INYO, SOUTHERN NYE, CLARK, AND
CENTRAL MOHAVE COUNTIES LATER TODAY, WITH MORE ROBUST CONVECTION
REDEVELOPING ACROSS SAN BERNARDINO COUNTY. WINDS WILL LIKELY BE A
BIT ERRATIC AND GUSTY AT TIMES NEAR ANY PRECIPITATION, PARTICULARLY
THE STRONGER STORMS EXPECTED THIS AFTERNOON AND EVENING. THE
WIDESPREAD MOISTURE AND PRECIPITATION WILL BRING CIGS DOWN TO 8-
10KFT IN MOST OF THE AFOREMENTIONED AREAS, AND POSSIBLY AS LOW AS
4KFT IN PARTS OF THE OWENS VALLEY. SKY CONDITIONS ARE EXPECTED TO
IMPROVE TONIGHT ACROSS THE MOJAVE DESERT.
SPOTTER INFORMATION STATEMENT
SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING
PROCEDURES.
DISCUSSION/AVIATION...WOODS
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