338  
FXUS65 KVEF 170826  
AFDVEF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LAS VEGAS NV  
126 AM PDT WED SEP 17 2025  
   
KEY MESSAGES  
 
* SEASONABLY WARM AND DRY CONDITIONS WILL PERSIST TODAY.  
 
* INCREASING MOISTURE ASSOCIATED WITH THE REMNANTS OF MARIO WILL  
MOVE INTO THE REGION THURSDAY THROUGH FRIDAY, BRINGING CHANCES FOR  
SHOWERS AND THUNDERSTORMS. LOCALLY HEAVY RAIN AND HIGH RAINFALL  
RATES WILL LEAD TO AN INCREASED RISK OF FLASH FLOODING.  
 
   
DISCUSSION  
THROUGH TUESDAY. THE TROPICAL MOISTURE IS KNOCKING ON  
OUR SOUTHERN DOOR. SATELLITE LOOP SHOWED CIRRUS OUTFLOW FROM THE  
REMNANTS OF MARIO NEARING OUR SOUTHERN CWA BORDER, AND SURFACE OBS  
SHOWED DEWPOINTS UP 10-20F IN THE PAST 24 HOURS AT SITES INCLUDING  
KDAG, KNXP, AND KBLH. ON A POSITIVE NOTE, RECENT MODEL RUNS SHOW  
VERY LITTLE CHANGE FROM 24 HOURS AGO WITH RESPECT TO PRECIPITATION  
TIMING AS WELL AS THE MOST PROBABLE AMOUNTS (25TH TO 75TH PERCENTILE  
RANGE), WHICH INCREASES FORECAST CONFIDENCE. THAT SAID, THERE IS  
STILL SIGNIFICANT UNCERTAINTY IN ONE VERY IMPORTANT REGARD - WILL  
THERE BE ENOUGH SUNSHINE IN BETWEEN THE CLOUDS THURSDAY AND/OR  
FRIDAY TO ALLOW FOR DESTABILIZATION AND INTENSE RAINFALL RATES, OR  
WILL SOLIDLY OVERCAST SKIES PREVENT INSTABILITY FROM BEING REALIZED,  
RESULTING IN LESS-HAZARDOUS STRATIFORM RAIN? BECAUSE OF THAT  
UNCERTAINTY, WILL NOT ISSUE A FLASH FLOOD WATCH AT THIS TIME. BEST  
GUESS IS THAT THE BEST HEAVY RAIN POTENTIAL WILL BE ALONG AND WEST  
OF HIGHWAY 95 THURSDAY AND THURSDAY NIGHT. BEST FORCING EXITS BY  
FRIDAY NIGHT, LEAVING MORE OF A LOW-GRADE MONSOON PATTERN IN PLACE  
FOR SATURDAY AND POSSIBLY SUNDAY. NOT MUCH CONFIDENCE IN MONDAY OR  
TUESDAY, BUT THE OVERALL PATTERN FAVORS MOSTLY DRY WEATHER WITH  
TEMPERATURES CLIMBING BACK ABOVE NORMAL FOR LATE SEPTEMBER.  
 
   
AVIATION...FOR HARRY REID...FOR THE 06Z FORECAST PACKAGE  
WINDS  
WILL FOLLOW TYPICAL DIURNAL DIRECTIONAL PATTERNS WITH SUSTAINED  
SPEEDS OF 10 KNOTS OR LESS. SOUTHWESTERLY WINDS WILL BECOME LIGHT  
AND VARIABLE DURING THE EARLY MORNING HOURS. THESE LIGHT AND  
VARIABLE WINDS WILL CONTINUE INTO THE LATE MORNING WHEN WINDS WILL  
SETTLE IN FROM A MORE EASTERLY DIRECTION THROUGH THE AFTERNOON  
AND INTO THE EARLY EVENING. HIGH CLOUDS WILL BEGIN TO PUSH INTO  
SOUTHERN NEVADA OVERNIGHT TONIGHT, WITH MID-LEVEL CLOUDS MOVING IN  
TOMORROW EVENING. TEMPERATURES ARE NOT EXPECT TO REACH 100  
DEGREES, BUT WILL CLIMB TO THE UPPER 90S BETWEEN 21 AND 01Z.  
 
FOR THE REST OF SOUTHERN NEVADA, NORTHWEST ARIZONA AND SOUTHEAST  
CALIFORNIA...FOR THE 06Z FORECAST PACKAGE... HIGH CLOUDS WILL  
PUSH INTO THE AREA FROM THE SOUTH OVERNIGHT AND THROUGHOUT THE DAY  
TOMORROW. MID-LEVEL CLOUDS WILL BEGIN TO INCREASE LATE TOMORROW  
AFTERNOON/EARLY TOMORROW EVENING. THERE IS A LOW CHANCE THAT  
SHOWERS WILL BEGIN TO PUSH INTO THE AREA AS EARLY AS TOMORROW  
EVENING. HOWEVER, CHANCES FOR SHOWERS WILL INCREASE DURING THE  
OVERNIGHT HOURS AS MOISTURE MOVES INTO THE AREA. CONFIDENCE  
REGARDING WHETHER OR NOT ANY OF THESE SHOWERS WILL IMPACT  
TERMINALS IS LOW AT THIS TIME. OUTSIDE OF INFLUENCE FROM ANY  
SHOWERS, WHICH MAY RESULT IN ERRATIC GUSTY WINDS, WINDS ACROSS THE  
REGION WILL FOLLOW TYPICAL DIURNAL DIRECTIONAL TRENDS WITH SPEEDS  
OF 12 KNOTS OR LESS. THE ONE EXCEPTION TO THIS WILL BE THE  
WESTERN MOJAVE DESERT TOMORROW NIGHT WHEN BREEZY SOUTHWESTERLY  
WINDS WILL PICK UP.  
 
   
SPOTTER INFORMATION STATEMENT  
SPOTTERS ARE ENCOURAGED TO REPORT  
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING  
PROCEDURES.  
 
 
 
 
DISCUSSION...MORGAN  
AVIATION...STESSMAN  
 
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:  
HTTPS://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER  
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