Heat in California, September 23, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1000 AM PDT WED SEP 23 2015

.SYNOPSIS...THE FIRST DAY OF FALL WILL USHER IN A PERIOD OF
UNSEASONABLY WARM TEMPERATURES AND MOSTLY DRY CONDITIONS THAT WILL
EXTEND THROUGH THE WEEKEND. THERE IS A SMALL CHANCE OF AFTERNOON
THUNDERSTORMS OVER THE MOUNTAINS OF CLARK AND MOHAVE COUNTY TODAY
BUT OTHERWISE...NO SIGNIFICANT WEATHER IS EXPECTED OVER THE NEXT
WEEK. &&

.UPDATE...THE 12Z LAS VEGAS SOUNDING AND NAM/GFS BUFR SOUNDINGS
INDICATE ENOUGH MOISTURE AND INSTABILITY STILL LINGER THAT
CONVECTION CANNOT BE COMPLETELY RULED OUT OVER THE SHEEP
RANGE...SPRING MOUNTAINS AND MCCULLOUGH RANGE THIS AFTERNOON. THE
HRRR ALSO DEPICTS CONVECTION OVER THESE MOUNTAINS FROM 21Z TO 00Z.
THE POP/WX GRIDS WERE ADJUSTED TO ADDED THE MENTION OF ISOLATED
THUNDERSTORMS.
&&

.AVIATION...FOR MCCARRAN...EASTERLY WIND COMPONENTS ARE POSSIBLE
THIS AFTERNOON WITH WIND SPEEDS GENERALLY UNDER 8 KTS. LIGHT DIURNAL
WIND TRENDS ARE EXPECTED THROUGH FRIDAY WITH NO SIGNIFICANT WEATHER.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...MAINLY LIGHT WINDS FAVORING TYPICAL DIURNAL TRENDS ARE
EXPECTED THROUGH THURSDAY MORNING. A FEW ISOLATED SHOWERS OR BRIEF
THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON OVER THE MOUNTAINS OF
SOUTHERN NEVADA AND NORTHWEST ARIZONA WITH DRY CONDITIONS ELSEWHERE.
NO SIGNIFICANT WEATHER IS EXPECTED THROUGH FRIDAY. &&

.SHORT TERM...TODAY THROUGH FRIDAY.

LAST EVENING...ONE THUNDERSTORM CELL NORTHEAST OF WIKIEUP PRODUCED
NEARLY A HALF INCH OF RAIN IN 30 MINUTES AND FEW OTHER ISOLATED
STORMS DEVELOPED...PRIMARILY ALONG OUTFLOW BOUNDARIES...BUT DIDN'T
AMOUNT TO MUCH. AS OF THIS WRITING, NO SHOWERS OR STORM CELLS ARE
OCCURRING WITHIN THE CWA. IN FACT, SATELLITE IMAGERY SHOWS
PREDOMINANTLY CLEAR SKIES WITH ONLY A FEW CLOUDS HERE AND THERE TO
GREET THE BEGINNING OF THE AUTUMN SEASON.

PACIFIC ENERGY THAT MOVED THROUGH THE AREA YESTERDAY HAS MOVED AWAY
AND HAS BEEN REPLACED BY RIDGING. PRECIPITABLE WATER AND 850 DEWPTS
ARE FORECAST TO DECREASE AS THE DAY WEARS ON WITH WARMER AIR ALOFT
GENERALLY CAPPING CONVECTION IN MOST AREAS TODAY. THE EXCEPTION
WOULD BE MOHAVE COUNTY WHERE FORECAST NAM12 AND GFS40 SOUNDINGS SHOW
BETTER INSTABILITY STILL IN PLACE THIS AFTERNOON WITH GOOD SURFACE
HEATING UNDER SUNNY CONDITIONS. INTRODUCED A SMALL CHANCE OF
MOUNTAIN THUNDERSTORMS TO COVER THE POTENTIAL. PRECIPITATION CHANCES
GO TO ZERO TONIGHT EVERYWHERE AND CONTINUED DRY CONDITIONS ARE
EXPECTED THROUGH FRIDAY.

HIGH TEMPERATURES TODAY WILL WARM TO AROUND 5 DEGREES ABOVE NORMAL
AND ARE EXPECTED TO REACH TRIPLE DIGITS THURSDAY AND FRIDAY IN LAS
VEGAS AND OTHER DESERT LOCATIONS. DEFINITELY WARM FOR THE TIME OF
YEAR WHEN COMPARED TO AVERAGES BUT STILL FAIRLY COMMON. AS
SOUTHWESTERLY FLOW SETS UP THURS/FRI AND MINOR PERTURBATIONS MOVE
THROUGH THE FLOW AT VARIOUS TIMES, SOME AREAS COULD SEE GUSTY
AFTERNOON WIND CONDITIONS BOTH DAYS BUT NOTHING OF SIGNIFICANCE IS
EXPECTED.

.LONG TERM...SATURDAY THROUGH WEDNESDAY

GFS HAS COME MORE IN-LINE WITH THE ECMWF/CMC WHICH HAVE BEEN THE
MODELS OF CHOICE. STRONG RIDGE OVER THE INTERMOUNTAIN WEST THIS
WEEKEND WILL ONLY BE NUDGED SLIGHTLY EASTWARD BY THE MID-LATTER PART
OF NEXT WEEK. HIGH TEMPERATURES WILL BE AROUND 10 DEGREES ABOVE
NORMAL THIS WEEKEND WITH A FEW RECORDS POTENTIALLY BEING TIED OR
BROKEN. ONLY SLIGHT REPRIEVE FROM THE WARMTH NEXT WEEK WITH
TEMPERATURES STAYING ABOVE NORMAL.
&&

.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED
HOWEVER SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER
ACCORDING TO STANDARD OPERATING PROCEDURES.
&&

UPDATE/AVIATION...ADAIR
PREV DISCUSSION...SALMEN/PIERCE

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