Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 280359 AAA
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
900 PM PDT THU AUG 27 2015

.SYNOPSIS...A DECREASING THUNDERSTORM TREND IS EXPECTED OVER THE
NEXT COUPLE OF DAYS AS A DRIER SOUTHWEST FLOW IS FORECAST TO
DOMINATE. TEMPERATURES WILL CLIMB BACK TO ABOVE NORMAL READINGS
FRIDAY AND SATURDAY THEN SLIGHTLY COOLER CONDITIONS ARE EXPECTED
SUNDAY INTO EARLY NEXT WEEK WITH TROUGHING ALONG THE WEST COAST.
&&

.UPDATE... THINGS HAVE QUIETED DOWN OVER MUCH OF THE AREA WITH THE
EXCEPTION OF SOUTHERN SAN BERNARDINO COUNTY WHERE A STRONG
THUNDERSTORM HAS DEVELOPED WEST OF VIDAL JUNCTION AND ANOTHER TRYING
TO FORM NEAR TWENTYNINE PALMS. THESE AREAS DID NOT HAVE POP IN FOR
THE EVENING AND HAVE UPDATED THE GRIDS TO ADD THOSE. DID LOWER POPS
ELSEWHERE AS SHOWERS AND THUNDERSTORMS HAVE DECREASED.
&&

PREV DISCUSSION
312 PM PDT THU AUG 27 2015

.SHORT TERM...THROUGH SUNDAY NIGHT...

STRONG WESTERLY FLOW ALOFT AND LACK OF ANY WEATHER DISTURBANCE IS
LIMITING A MORE ACTIVE THUNDERSTORM DAY TODAY. THUNDERSTORMS THUS
FAR HAVE BEEN LARGELY CONFINED TO THE EASTERN HALF OF THE FORECAST
AREA AS EXPECTED BUT A FEW ISOLATED CELLS HAVE FORMED A BIT FURTHER
WEST. THE LAS VEGAS VALLEY HASN`T HAD MUCH OF A CHANCE AS EARLY
STORMS THAT FORMED OVER THE SPRING MOUNTAINS AND FURTHER SOUTH HAS
PRODUCED AN EXTENSIVE CLOUD SHIELD THAT COVERED THE VALLEY.

FRIDAY IS EXPECTED TO BRING LESS THUNDERSTORM COVERAGE WITH MOISTURE
BOTH AT THE SURFACE AND THROUGH THE ATMOSPHERIC COLUMN ON THE
DECREASE. MODELS CONTINUE TO SHOW WEAK INSTABILITY OVER THE EASTERN
HALF OF THE AREA BUT DUE TO EXPECTED WARMING ALOFT, STORMS ARE
EXPECTED TO BE LIMITED TO MAINLY THE HIGHER TERRAIN. THE NAM12
FORECAST SOUNDING FOR VEGAS SHOWS THIS WARMER AIR ALOFT WITH A
CAPPING INVERSION BETWEEN 600-500MB. SURFACE TEMPERATURES WOULD NEED
TO REACH ROUGHLY 103 OR 104 DEGREES TO BREACH THIS CAP LAYER. THE
HIGH TEMPERATURE FORECAST IS 105 DEGREES BUT DEWPOINTS SHOULD BE
DOWN IN THE MID 40S BY THAT TIME.

THE WEEKEND FORECAST REMAINS DRY ALTHOUGH SOME MOISTURE IS FORECAST
TO LINGER IN MOHAVE COUNTY BOTH SATURDAY AND SUNDAY. THERE REMAINS A
POSSIBILITY THAT SLIGHT CHANCES MAY BE ADDED BACK INTO MOHAVE COUNTY
AT SOME POINT IF MODELS CONTINUE TO SHOW THIS. AFTERNOON WINDS WILL
BE NOTICEABLY BREEZY BOTH DAYS WITH WIND SPEEDS OF 10-20 MPH AND
HIGHER GUSTS POSSIBLE ACROSS MUCH OF THE AREA. TEMPERATURES WILL TOP
OUT 4 OR 5 DEGREES ABOVE NORMAL SATURDAY BEFORE RETURNING TO NEAR
NORMAL SUNDAY.

.LONG TERM...MONDAY THROUGH THURSDAY.

THE ONLY CHANGES MADE TO THE EXTENDED WHERE TO INCREASE AFTERNOON
WINDS AND TWEAK SKY COVER TO BETTER MATCH NEIGHBORS SKY GRIDS.
OTHERWISE THE PREVIOUS GRIDDED FORECAST AND DISCUSSION BELOW HOLDS.

A LARGE SCALE TROUGH WILL SET UP ALONG THE WEST COAST AND WILL
PERSIST THROUGH THE LONG TERM. THIS WILL RESULT IN A MAINLY DRY
SOUTHWEST FLOW OVER THE FORECAST AREA WITH TEMPERATURES JUST A
LITTLE ABOVE NORMAL. THERE WILL BE SOME HIGH CLOUDS AT TIMES BUT
LOWER LEVEL MONSOON MOISTURE WILL LIKELY LINGER JUST EAST OF MOHAVE
COUNTY. THE 00Z RUN OF THE GFS IS KEEPING THAT MONSOON MOISTURE A
BIT FARTHER WEST...LAPPING AT EASTERN PORTIONS OF MOHAVE COUNTY BUT
THE OTHER MODELS KEEP IT EAST SO I DID NOT ADD ANY THUNDERSTORM
CHANCES BUT THAT TREND WILL NEED TO BE MONITORED.
&&

.AVIATION...FOR MCCARRAN...MAINLY LIGHT AND VARIABLE WINDS UNDER 8
KTS ARE EXPECTED THROUGH THE EARLY EVENING HOURS THEN EVENTUALLY
SHIFTING AROUND TO THE SOUTHWEST AFTER SUNSET. THE EXCEPTION WOULD
BE ANY THUNDERSTORM OUTFLOW WHICH COULD BRING GUSTY WINDS TO THE
TERMINAL FROM VARIOUS DIRECTIONS. FEW-SCT CLOUDS AROUND 10-12K FEET
WITH MOUNTAIN THUNDERSTORMS THROUGH THE AFTERNOON.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WINDS GENERALLY UNDER 10 KTS UNLESS INFLUENCED BY
THUNDERSTORM OUTFLOW. ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH
THE EARLY EVENING OVER MOHAVE COUNTY AND THE HIGHER TERRAIN OF
CLARK, EASTERN SAN BERNARDINO AND LINCOLN COUNTIES. CIGS DOWN TO 8K
FEET ARE POSSIBLE IN AREAS OF THUNDERSTORMS OTHERWISE FEW-SCT 10-12K
FEET CAN BE EXPECTED.
&&

.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&

$$

GORELOW/SALMEN

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