340
FXUS65 KVEF 151948
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1248 PM PDT MON SEP 15 2025
KEY MESSAGES
* WARM AND DRY WEATHER WILL CONTINUE THROUGH WEDNESDAY.
* SHOWERS AND THUNDERSTORM CHANCES RETURN WEDNESDAY NIGHT THROUGH
THE WEEKEND, WITH THURSDAY AND FRIDAY BEING THE HIGHEST POTENTIAL
FOR WIDESPREAD RAINFALL AND IMPACTS.
DISCUSSION
THROUGH SUNDAY.
HIGH PRESSURE REMAINS OVER THE REGION THROUGH WEDNESDAY, RESULTING
IN MOSTLY CLEAR SKIES, LIGHT WINDS, AND WARMING TEMPERATURES. BY
WEDNESDAY AFTERNOON, HIGH TEMPERATURES WILL RUN SLIGHTLY ABOVE
NORMAL. WITH INCREASING MOISTURE, TEMPERATURES AFTER WEDNESDAY WILL
DROP BACK TO NORMAL OR BELOW NORMAL LEVELS.
INCREASING CONFIDENCE FOR A DRAMATIC SHIFT IN THE WEATHER PATTERN
THE SECOND HALF OF THE WEEK AS AN UPPER LEVEL TROUGH SITTING OFF THE
CALIFORNIA COAST INTERACTS WITH TROPICAL MOISTURE ASSOCIATED WITH
MARIO. WHILE THE TROPICAL SYSTEM ITSELF WILL REMAIN OFFSHORE,
MOISTURE WILL ADVECT INTO THE REGION ON SOUTHWEST FLOW STARTING
WEDNESDAY NIGHT. THURSDAY THROUGH FRIDAY, SIGNIFICANT MOISTURE WITH
OVER 200% OF NORMAL PWATS WILL BE SITUATED OVER THE AREA, WITH HIGH
PROBABILITIES FOR OVER 1.00 INCH PWATS FOR AREAS SOUTH OF THE I-15
AS WELL AS IN DEATH VALLEY BY FRIDAY. MEANWHILE, MODELS ARE COMING
INTO BETTER CONSENSUS THAT FORCING WILL INCREASE AS THE OFFSHORE LOW
SHIFTS INTO SOUTH-CENTRAL CALIFORNIA. WITH AMPLE MOISTURE AND DECENT
UPPER LEVEL SUPPORT, INCREASING POPS ARE EXPECTED THURSDAY AND
FRIDAY, WITH THE HIGHEST CHANCES FOR PRECIPITATION AND IMPACTS OVER
SAN BERNARDINO COUNTY INTO DEATH VALLEY AND FAR SOUTHERN NEVADA
WHERE THE BEST FORCING WILL SET UP. THERE REMAINS A SIGNIFICANT
AMOUNT OF UNCERTAINTY BEYOND THAT AS SMALL SCALE FEATURES THURSDAY
AND FRIDAY DEFINE EXACT AMOUNTS AND POTENTIAL IMPACTS. THERE IS AT
LEAST A MARGINAL RISK FOR HEAVY RAIN LEADING TO FLASH FLOODING IN
SAN BERNARDINO COUNTY INTO DEATH VALLEY AND FAR SOUTHERN NEVADA,
WITH WPC EXCESSIVE RAINFALL HIGHLIGHTING THIS THURSDAY INTO FRIDAY.
ADDITIONAL DETAILS AND IMPACTS BEYOND THAT REMAIN UNCLEAR AT THIS
TIME.
MOISTURE WILL LINGER INTO THE WEEKEND, BUT SHOULD WANE COMPARED TO
THURSDAY AND FRIDAY. FORCING WILL ALSO BE LESS ROBUST OVER THE
WEEKEND, WHICH MEANS SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
SATURDAY AND SUNDAY BUT WILL FOLLOW A MORE TYPICAL MONSOON-TYPE SET
UP WITH DIURNAL, LOW-END CONVECTIVE TRENDS AND THUNDERSTORMS
FAVORING THE TERRAIN.
AVIATION...FOR HARRY REID...FOR THE 18Z FORECAST PACKAGE
TYPICAL LIGHT WIND PATTERNS ARE EXPECTED THROUGH THE PERIOD.
EASTERLY WINDS WILL SET UP FOR THE EARLY AFTERNOON, BECOMING MORE
SOUTHEAST LATER IN THE AFTERNOON. SPEEDS REMAIN UNDER 10KT, THOUGH A
FEW UPTICKS WITH GUSTS TO AROUND 15KT ARE POSSIBLE WITH THE
SOUTHEAST WINDS. SOUTHWEST WINDS UNDER 8KT WILL RETURN AFTER SUNSET.
A REPEAT OF TODAY'S WINDS IS EXPECTED TUESDAY. SKIES WILL BE CLEAR
WITH TEMPERATURES UNDER 100 DEGREES.
FOR THE REST OF SOUTHERN NEVADA, NORTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...FOR THE 18Z FORECAST PACKAGE...WINDS WILL GENERALLY
FOLLOW TYPICAL DAILY DIRECTIONAL PATTERNS WITH SPEEDS OF LESS THAN
10KT THROUGH THE FORECAST PERIOD. SOUTH TO SOUTHEASTERLY WINDS PICK
UP IN THE OWENS VALLEY INCLUDING KBIH IN THE AFTERNOON WITH GUSTS OF
AROUND 20KT POSSIBLE. SKIES WILL BE CLEAR AREAWIDE.
SPOTTER INFORMATION STATEMENT
SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING
PROCEDURES.
DISCUSSION/AVIATION...NICKERSON
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