597
FXUS65 KVEF 171135
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
435 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 12Z FORECAST PACKAGE
LIGHT
AND DIURNAL WINDS EXPECTED TODAY, WITH SPEEDS GENERALLY 8 KTS OR
LESS. EXPECT LIGHT EAST-NORTHEASTERLY WINDS THROUGH THE MORNING AND
EARLY-AFTERNOON. CANNOT RULE OUT A STRAY GUST TO 15 KTS THIS
AFTERNOON FROM THE EAST. WINDS WILL BECOME SOUTHWESTERLY OVERNIGHT,
RETURNING TO THE EAST-NORTHEAST THURSDAY MORNING. FEW-SCT AOA 25 KFT
THROUGH THE DAY TODAY, INCREASING TO BKN-OVC OVERNIGHT. SCT-BKN AOA
12 KFT PUSH INTO SOUTHERN NEVADA AFTER SUNSET AND PERSIST THROUGH
THE REMAINDER OF THE TAF PERIOD. BEST CHANCES OF 98-100 DEGREES
THIS AFTERNOON EXIST BETWEEN 23 AND 01Z.
FOR THE REST OF SOUTHERN NEVADA, NORTHWESTERN ARIZONA AND
SOUTHEASTERN CALIFORNIA...FOR THE 12Z FORECAST PACKAGE...LIGHT AND
DIURNAL WINDS EXPECTED TODAY, WITH SPEEDS GENERALLY 8 KTS OR LESS.
THE EXCEPTION WILL BE KDAG, WHERE GUSTY WEST WINDS BETWEEN 20 AND 25
KTS WILL PICK UP AFTER SUNSET. BKN-OVC HIGH CLOUDS WILL INCREASE
SOUTH-TO-NORTH ACROSS THE REGION TODAY, WITH SCT-BKN MID-LEVEL
CLOUDS REACHING KDAG, KBIH, KEED, AND KIFP THIS AFTERNOON AND KLAS,
KVGT, KHND THIS EVENING. SLIGHT (5-10 PERCENT) CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS THE SOUTHERN MOJAVE DESERT TODAY, WITH LOWER
CONFIDENCE OF DIRECT IMPACT TO TERMINALS. WITH ACTIVITY THAT OCCURS
OVER TERMINALS, EXPECT CIGS DROPPING TO 10 KFT OR LESS, ERRATIC
GUSTY WINDS, AND INSTANCES OF LIGHTNING. CHANCES OF IMPACTS TO
TERMINALS INCREASE ON THURSDAY AREAWIDE.
SPOTTER INFORMATION STATEMENT
SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING
PROCEDURES.
DISCUSSION...MORGAN
AVIATION...SOULAT
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