817
FXUS65 KVEF 021735
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1035 AM PDT TUE SEP 2 2025
AFD UPDATED TO INCLUDE 18Z AVIATION DISCUSSION BELOW...
KEY MESSAGES
* MONSOONAL MOISTURE SURGES INTO THE FORECAST AREA TODAY, RESULTING
IN WIDESPREAD SHOWER AND THUNDERSTORMS CAPABLE OF PRODUCING FLASH
FLOODING.
* MOISTURE REMAINS IN PLACE THROUGH MIDWEEK BEFORE SLOWLY SCOURING
OUT OF THE REGION, SHIFTING PRECIPITATION CHANCES FURTHER EAST
EACH DAY.
DISCUSSION
THE RIDGE OF HIGH PRESSURE OVER THE DESERT SOUTHWEST WILL SHIFT
SLIGHTLY EASTWARD TODAY, AS A RESULT OF A SHORTWAVE APPROACH OFF THE
CALIFORNIA COAST. THIS EASTWARD SHIFT WILL AID IN MONSOONAL MOISTURE
ADVECTION INTO OUR CWA TODAY, DUE TO THE RESULTANT SOUTHERLY FLOW.
PWATS WILL RANGE FROM 1.25 TO 1.50 INCHES ACROSS OUR SOUTHERN ZONES,
INCLUDING SAN BERNARDINO COUNTY, CLARK COUNTY, AND SOUTHWESTERN
MOHAVE COUNTY. IN ADDITION TO THIS MOISTURE, AN EASTERLY WAVE WILL
ROTATE AROUND THE AFOREMENTIONED HIGH PRESSURE TO COMBINE WITH THE
INCOMING CALIFORNIA SHORTWAVE. AS THIS OCCURS, THE RESULTANT
VORTICITY LOBE WILL PUSH NORTHWARD THROUGH SOUTHEASTERN CALIFORNIA
THIS AFTERNOON, PROVIDING NECESSARY FORCING FOR WIDESPREAD
THUNDERSTORMS. CONVECTION WILL INITIALLY FAVOR THE HIGHER TERRAIN,
AS CLOUD COVER MAY INHIBIT LIFT FROM DAYTIME HEATING IN VALLEY
LOCATIONS. WITH AMPLE MOISTURE AND FORCING, THE PRIMARY THREATS
TODAY WILL BE MODERATE-TO-HEAVY RAIN, FREQUENT LIGHTNING, AND FLASH
FLOODING. BEST CHANCES OF WIDESPREAD FLASH FLOODING EXIST ACROSS SAN
BERNARDINO COUNTY AND DEATH VALLEY, WHERE FLASH FLOOD WATCHES ARE IN
EFFECT FROM 9 AM THIS MORNING THROUGH 1 AM PDT TONIGHT.
TODAY'S VORTICITY LOBE WILL WEAKEN SOMEWHAT ON WEDNESDAY AS IT
SHIFTS OVER SOUTH-CENTRAL NEVADA. MOISTURE WILL CONTINUE TO INCH
FURTHER NORTH ON WEDNESDAY, WITH PWAT VALUES ACROSS OUR SOUTHERN
ZONES INCREASING TO 1.50 TO 1.75 INCHES. AS SUCH, EXPECT WIDESPREAD
SHOWERS AND THUNDERSTORMS ONCE AGAIN ON WEDNESDAY, WITH BEST CHANCES
SPREADING FURTHER EAST. THUNDERSTORMS ON WEDNESDAY WILL BE
PRODUCTIVE RAIN-MAKERS, WITH HIGH RAIN RATES AND INSTANCES OF FLASH
FLOODING EXPECTED ONCE AGAIN. CONFIDENCE REGARDING THE LOCATION OF
THESE STORMS IS LOW AT THE MOMENT, SO THE FLOOD WATCH HAS NOT BEEN
EXTENDED INTO WEDNESDAY AT THIS TIME. MOISTURE SLOWLY SCOURS
NORTHWEST-TO-SOUTHEASTWARD OUT OF THE REGION THROUGH THE REMAINDER
OF THE WORK WEEK, WITH PRECIPITATION CHANCES BECOMING MORE AND MORE
CONFINED TO THE EASTERN ZONES EACH DAY. EXPECT BELOW-NORMAL
TEMPERATURES THROUGH THE FORECAST PERIOD, AS A RESULT.
AVIATION...FOR HARRY REID...FOR THE 18Z FORECAST PACKAGE
A VERY COMPLEX AND LOW CONFIDENCE FORECAST IS IN STORE FOR MUCH
OF THE LAS VEGAS VALLEY REGION. WITH ONGOING MORNING
SHOWERS/STORMS TO THE SOUTH AND WEST OF THE TERMINAL, UNCERTAINTY
IS HIGH IN HOW EXISTING CLOUD COVER AND OUTFLOW WILL AFFECT
AFTERNOON CONDITIONS. WINDS WILL REMAIN SOUTH/SOUTHWEST THROUGH
EARLY AFTERNOON, SHIFTING A BIT MORE SOUTHEASTERLY BY 20-21Z. WIND
SPEEDS SHOULD GENERALLY REMAIN 10-12 KNOTS OR LESS. THIS
AFTERNOON, WITH ABUNDANT MOISTURE AND THE EXPECTATION OF A FEW
BREAKS IN THE CLOUDS, AT LEAST A FEW THUNDERSTORMS ARE EXPECTED TO
DEVELOP. HEAVY RAINFALL WILL ACCOMPANY ANY STORMS WITH REDUCED
VISIBILITIES. HOWEVER, CONFIDENCE REMAINS LOW THAT THE TERMINAL
WILL BE DIRECTLY IMPACTED. CONFIDENCE IS HIGH, HOWEVER, IN GUSTY
OUTFLOW WINDS FROM ANY NEARBY STORMS, SO WE HAVE MAINTAINED A
TEMPO FOR THIS LIKELIHOOD. FROM 00Z ON, CONFIDENCE IS
SUFFICIENTLY LOW IN STORMS THAT THE TEMPO HAS BEEN REMOVED. STORM
ACTIVITY MAY LINGER INTO THE OVERNIGHT HOURS WITH THE POTENTIAL
FOR ADDITIONAL GUSTY OUTFLOW WINDS. BY 10Z-12Z, ACTIVITY SHOULD
WANE WITH SCATTERED TO OVERCAST MID LEVEL CEILINGS. WHILE
TEMPERATURES ARE FORECAST TO TOUCH THE LOW 100S BETWEEN 21-23Z,
EXISTING CLOUD COVER AND RAIN COOLED OUTFLOWS MAY MAKE IT
DIFFICULT TO REACH.
FOR THE REST OF SOUTHERN NEVADA, NORTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...FOR THE 18Z FORECAST PACKAGE...A COMPLEX FORECAST IS
IN STORE WITH SCATTERED SHOWERS/STORMS ONGOING AND MORE EXPECTED
INTO THE AFTERNOON. WINDS TO GENERALLY REMAIN SOUTH/SOUTHEAST 15
KNOTS OR LESS, EXCEPT WHERE NEARBY THUNDERSTORMS PROMOTE STRONG
GUSTY OUTFLOW WINDS, WHICH COULD AFFECT ALMOST ANY TERMINAL. A
MOSTLY DIURNAL WIND PATTERN IS EXPECTED AT KBIH, FURTHER REMOVED
FROM MORNING SHOWERS STORMS. ONGOING SHOWERS/STORMS TO MAINLY
AFFECT KDAG/KIFP/KEED THROUGH LATE MORNING. INTO THE AFTERNOON,
CONFIDENCE REMAINS LOW THAT ANY INDIVIDUAL TERMINAL WILL BE
IMPACTED BY A THUNDERSTORM, BUT IF THIS OCCURS, VERY HEAVY RAIN
WILL RESULT IN VISIBILITIES OF 1SM OR LESS, ALONG WITH GUSTY
WINDS. BROKEN TO OVERCAST MID LEVEL CEILINGS CAN BE EXPECTED
THROUGH MOST OF THE PERIOD.
SPOTTER INFORMATION STATEMENT
SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING
PROCEDURES.
DISCUSSION...SOULAT
AVIATION...AUSTIN
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