718
FXUS65 KVEF 281655
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
955 AM PDT MON SEP 28 2026
KEY MESSAGES
* INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS ARRIVE MONDAY AND
TUESDAY ALONG WITH COOLER TEMPERATURES.
* STRONGER STORMS ACROSS THE COLORADO RIVER VALLEY AND NORTHWESTERN
ARIZONA MAY PRODUCE FLASH FLOODING, SMALL HAIL, AND STRONG WIND
GUSTS.
* MILD WEATHER AND WARMING TEMPERATURES ARE EXPECTED DURING THE
SECOND HALF OF THE WEEK.
DISCUSSION
TODAY THROUGH NEXT WEEKEND.
EARLY MORNING SATELLITE IMAGERY SHOWS TROPICAL MOISTURE STREAMING
ACROSS THE SOUTHEASTERN PORTION OF OUR FORECAST AREA WHILE A TROUGH
DIGS ALONG THE COAST OF CALIFORNIA, BEGINNING TO MOVE INLAND. THIS
TROUGH WILL MOVE THROUGH THE REGION TODAY AND TOMORROW, BRINGING
INCREASED PRECIPITATION CHANCES TO SOUTHERN NEVADA, SOUTHEASTERN
CALIFORNIA, AND NORTHWESTERN ARIZONA. AS THIS TROUGH INTERACTS WITH
THE TROPICAL MOISTURE, SCATTERED-TO-WIDESPREAD SHOWERS AND
THUNDERSTORMS CAPABLE OF PRODUCING HEAVY RAIN ARE EXPECTED ACROSS
THE EASTERN HALF OF OUR FORECAST AREA. THE NORTHWESTERN PORTION OF
OUR FORECAST AREA WILL SEE INCREASED CHANCES FOR ISOLATED SHOWERS
AND THUNDERSTORMS, MAINLY IN AREAS OF HIGHER TERRAIN. SINCE MOISTURE
IN THE NORTHWESTERN PORTION OF OUR FORECAST AREA WILL NOT BE AS
ABUNDANT, PRECIPITATION WILL BE ON THE LIGHTER-TO-MODERATE SIDE.
GUSTY OUTFLOW WINDS, LIGHTNING, AND SMALL HAIL (GRAUPEL) WILL BE
POSSIBLE WITH THESE STORMS IN THE NORTHWESTERN PORTION OF OUR
FORECAST AREA THIS AFTERNOON.
THE EASTERN HALF OUR FORECAST AREA WILL SEE AN ELEVATED FLASH FLOOD
RISK TODAY AS THE DYNAMICS FROM THE AFOREMENTIONED TROUGH WORK WITH
THE ANOMALOUS TROPICAL MOISTURE TO FUEL SHOWERS AND THUNDERSTORMS
ACROSS THE AREA. THE HIGHEST RISK OF FLASH FLOODING WILL BE IN
NORTHWESTERN ARIZONA, WHERE THE WEATHER PREDICTION CENTER (WPC) HAS
HIGHLIGHTED MOHAVE COUNTY WITH A MODERATE (LEVEL 3 OF 4) EXCESSIVE
RAINFALL OUTLOOK (ERO), AND SOUTHERN NEVADA AND THE COLORADO RIVER
VALLEY WHERE WPC HAS PLACED A SLIGHT ERO (LEVEL 2 OF 4). LIGHT
PRECIPITATION IS ALREADY ONGOING ACROSS SOUTHEASTERN MOHAVE COUNTY,
WITH ANYWHERE FROM A FEW HUNDREDTHS TO 0.20 INCHES OF RAIN HAVING
FALLEN. THIS BAND OF LIGHTER SHOWERS WILL CONTINUE INTO THE EARLY
MORNING HOURS, WITH STRONGER SHOWERS AND THUNDERSTORMS DEVELOPING
ACROSS LINCOLN AND MOHAVE COUNTIES LATER THIS MORNING. MOHAVE COUNTY
WILL SEE NEARLY CONTINUOUS STORM ACTIVITY TODAY. ADDITIONAL
DEVELOPMENT WILL OCCUR ACROSS SOUTHERN NEVADA AND EASTERN SAN
BERNARDINO COUNTY DURING THE AFTERNOON AND EVENING. HIRES MODELS
HAVE CONSISTENTLY HIGHLIGHTED THE POTENTIAL (30 TO 50% CHANCE) FOR
STORMS CAPABLE OF PRODUCING RAIN RATES IN EXCESS OF AN INCH PER HOUR
ACROSS SOUTHERN NEVADA INTO THE LOWER COLORADO RIVER VALLEY LATE
THIS AFTERNOON INTO THE EVENING HOURS. GIVEN THE NEAR CONTINUOUS
STORMS EXPECTED IN MOHAVE COUNTY AND THE POTENTIAL FOR VERY HEAVY
RAIN ACROSS SOUTHERN NEVADA AND THE COLORADO RIVER VALLEY, A FLOOD
WATCH WILL GO INTO EFFECT AT 5:00 AM MST/PDT. ON TUESDAY, ADDITIONAL
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS THE EASTERN HALF
OF OUR FORECAST AREA AS THE TROUGH AXIS SWINGS THROUGH THE REGION
AND MOISTURE WRAPS AROUND THE LOW.
THE LOW WILL MOVE EAST OF THE AREA BY WEDNESDAY, TAKING MOISTURE AND
PRECIPITATION CHANCES ALONG WITH IT. HIGH PRESSURE WILL BUILD OVER
THE REGION THROUGH THE REST OF THE WEEK AND PROMOTE A WARMING AND
DRYING TREND. HIGHS REACH NEAR-NORMAL VALUES ON THURSDAY, THEN
GENERALLY REMAIN STEADY THROUGH THE REST OF THE WEEK. THIS INCLUDES
HIGHS IN THE LOW TO MID 90S IN LAS VEGAS, UPPER 80S TO LOW 90S IN
THE OWENS VALLEY, AND IN THE UPPER 90S IN THE COLORADO RIVER VALLEY.
THE HIGH WILL SUPPORT LIGHTER WINDS AREAWIDE AS WELL.
AVIATION...FOR HARRY REID
FOR THE 18Z FORECAST
PACKAGE...ELEVATED SOUTHEASTERLY WINDS WILL VEER TO THE SOUTHWEST
EARLY IN THE FORECAST PERIOD, WITH GUSTS UP TO AROUND 20KT.
THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN
SURROUNDING THE VALLEY, WITH POTENTIAL FOR IMPACTS AT THE TERMINAL
DURING THE MID- TO LATE AFTERNOON. ERRATIC GUSTY OUTFLOW WINDS,
LIGHTNING, AND BRIEF REDUCTIONS IN CEILINGS/VISIBILITY DUE TO
RAINFALL ARE POSSIBLE WITH STORMS THAT MOVE OVER THE TERMINAL.
VICINITY THUNDERSTORMS WILL PERSIST UNTIL 12Z TUESDAY MORNING,
WITH LINGERING VICINITY SHOWERS THEREAFTER. OUTSIDE OF CONVECTION,
CEILINGS WILL BE SCT-BKN AROUND 10-12KFT, WITH LOW CONFIDENCE IN
THE WIND FORECAST THROUGH EARLY TUESDAY MORNING DUE TO POTENTIAL
OUTFLOW BOUNDARIES. HOWEVER, CONFIDENCE IN WIND DIRECTION
INCREASES THEREAFTER AS WINDS SHIFT TO THE NORTHWEST AND NORTH,
INCREASING WITH GUSTS TO 20-25KT EXPECTED LATE TUESDAY MORNING
THROUGH THE AFTERNOON.
FOR THE REST OF SOUTHERN NEVADA, NORTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...FOR THE 18Z FORECAST PACKAGE...WINDS ACROSS THE
REGION SHIFT TO THE SOUTH AND SOUTHWEST THIS AFTERNOON, WITH
GUSTS TO 20-25KT COMMON. ONE EXCEPTION IS KBIH, WHERE GUSTY
NORTHWESTERLY TO NORTHERLY WINDS WILL PREVAIL THROUGH THE FORECAST
PERIOD, AND ANOTHER IS KDAG, WHERE WINDS MAINTAIN A WESTERLY
DIRECTION WITH SOME SUBTLE VARIABILITY. THE PRIMARY AVIATION
CONCERN WILL BE SHOWERS AND THUNDERSTORMS ACROSS SOUTHERN NEVADA,
FAR SOUTHEASTERN CALIFORNIA, AND NORTHWESTERN ARIZONA THESE STORMS
ARE DEVELOPING AT ISSUANCE, WITH VICINITY THUNDERSTORMS MENTIONED
FOR LAS VEGAS VALLEY AND COLORADO RIVER VALLEY TERMINALS THROUGH
09-12Z TUESDAY, AND VICINITY SHOWERS PERSISTING THEREAFTER.
ERRATIC GUSTY OUTFLOW WINDS, LIGHTNING, AND CEILING/VISIBILITY
REDUCTIONS DUE TO HEAVY RAIN CAN BE EXPECTED IF THESE STORMS
IMPACT AREA TERMINALS. THE WIND FORECAST IN THE PRESENCE OF
CONVECTION REMAINS UNCERTAIN, HOWEVER, A NORTHWESTERLY TO
NORTHERLY WIND SHIFT WITH GUSTS TO 20-25KT IS EXPECTED LATE IN THE
FORECAST PERIOD.
SPOTTER INFORMATION STATEMENT
SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING
PROCEDURES.
DISCUSSION...MELTZER/STESSMAN
AVIATION...PHILLIPSON
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