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206
FXUS65 KVEF 311030
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
330 AM PDT THU JUL 31 2014

.SYNOPSIS...SHOWER AND THUNDERSTORM DEVELOPMENT WILL BE MORE
ISOLATED OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN UNDER A
SLIGHTLY DRIER AND MORE STABLE WESTERLY FLOW TODAY AND FRIDAY.
ANOTHER PUSH OF MOISTURE IS EXPECTED TO SPREAD UP ACROSS THE REGION
OVER THE WEEKEND FOR AN UPSWING IN SHOWERS AND THUNDERSTORMS.
&&

.SHORT TERM...THROUGH SATURDAY NIGHT...
ANY SHOWER OR THUNDERSTORM ACTIVITY ASSOCIATED WITH A DISTURBANCE
MOVING THROUGH WEST CENTRAL NEVADA HAS FOR THE MOST PART SHIFTED
NORTH AND EAST OF NORTHERN LINCOLN COUNTY THIS MORNING. ELSEWHERE,
SKIES ONCE AGAIN MOSTLY CLEAR UNDER CIRRUS.

THE DISTURBANCE MAY CONTINUE TO PROVIDE SOME WEAK DYNAMICS TO
PRIMARILY NORTHERN LINCOLN COUNTY TODAY AS IT MOVES EAST. OTHERWISE,
ACROSS THE SOUTHERN AREAS IT WILL BE ANOTHER DAY OF ISOLATED
CONVECTION ANCHORED TO THE MOUNTAINS. SAME GOES FOR FRIDAY, ALTHOUGH
WE COULD SEE AN INCREASE IN COVERAGE IN SOUTHERN MOHAVE COUNTY FROM
AN INCREASE IN MOISTURE DUE TO A GULF SURGE OR FROM OUTFLOW
SPREADING NORTHWARD FROM A MCS OVER NORTHWEST MEXICO OR SOUTHERN
ARIZONA. HIGH TEMPERATURES SHOULD TOP OUT A FEW DEGREES ABOVE NORMAL
TODAY AND FRIDAY.

THAT MOISTURE INCREASE WILL BE THE PRIMER FOR A POTENTIALLY ACTIVE
SATURDAY. BY SATURDAY/SATURDAY NIGHT, BROAD UPPER LOW PRESENTLY OVER
THE SOUTHERN BAJA PENINSULA WILL BE MOVING NORTH UP THE PENINSULA
PROVIDING SOME ADDITIONAL DYNAMICS TO THE MIX ACROSS THE MOJAVE
DESERT. THE UNCERTAINTY IN ALL THIS IS JUST HOW MUCH CLOUDINESS
FROM ANY MCS`S TO OUR SOUTH SPREADS NORTH ACROSS THE REGION.
HOWEVER, DYNAMICS WOULD LIKELY TRUMP ANY CLOUDINESS SETTING THE
STAGE FOR POTENTIAL HEAVY RAIN MAKERS. DUE TO SOME UNCERTAINTY NOT
CONFIDENT AT THIS TIME TO ISSUE A FLASH FLOOD WATCH. THERE IS ALSO
GREAT UNCERTAINTY IN THE TEMPERATURES AS SOME GUIDANCE HAS LAS VEGAS
IN THE LOW 90S WITH VALUES BETWEEN 100-105 ON THE HIGH END.

THOSE WITH OUTDOOR PLANS THIS WEEKEND SHOULD CONTINUE TO
MONITOR THE SITUATION FOR THE LATEST FORECAST.

.LONG TERM...SUNDAY THROUGH WEDNESDAY...MODELS ARE IN DECENT
AGREEMENT THAT A DISTURBANCE WILL MOVE NORTH FROM ARIZONA/NORTHERN
MEXICO SATURDAY AND SATURDAY NIGHT. AS THIS FEATURE PUSHES NORTH
SUNDAY THROUGH MONDAY NIGHT IT SHOULD PROVIDE AMPLE FORCING IN A
MOISTURE-RICH ENVIRONMENT [850-500MB MIXING RATIOS OF 6-9 G/KG
ACROSS ALL BUT THE FAR WESTERN AREAS] TO PRODUCE AT LEAST AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE REGION. WITH THE
ADDED DYNAMICS STORMS MAY CONTINUE THROUGH THE OVERNIGHT HOURS. THE
QUESTION WILL BE JUST HOW MUCH INSTABILITY WILL DEVELOP EACH DAY AND
THEREFORE HOW MUCH THUNDER THERE WILL ACTUALLY BE...THIS IS OFTEN
THE BIG QUESTION WITH THESE SYSTEMS. BOTH THE LATEST GFS AND ECMWF
INDICATE A PUNCH OF DRIER AIR OVER THE EASTERN CWA ABOVE 500MB BY
SUNDAY AFTERNOON WHICH MAY PRODUCE ENOUGH CLEARING TO ALLOW FOR SOME
SIGNIFICANT INSTABILITY TO DEVELOP. THE GFS IS NOT AT ALL
ENTHUSIASTIC ABOUT DEVELOPING INSTABILITY IN THIS AREA WHILE THE
ECMWF IS MORE AGREEABLE AND WAS LEANED ON MORE HEAVILY. LESS CLOUD
COVER IS FORECAST FOR MONDAY...BUT MOISTURE WILL ALSO BE DECREASING.
FOR THE MOMENT HAVE INDICATED HIGHER POPS FOR SUNDAY. ISOLATED
POCKETS OF ENHANCED SHEAR [MAINLY SUNDAY] COULD SET THE STAGE FOR A
FEW ORGANIZED STORMS...BUT WITH THE HIGH MOISTURE CONTENT THE MOST
SIGNIFICANT THREAT WILL BE FLASH FLOODING BOTH DAYS...ESPECIALLY IN
AREAS WITH VERY SLOW STORM MOTION. UNFORTUNATELY IT`S TOO EARLY TO
HAVE MUCH CONFIDENCE IN EXACTLY WHERE THESE AREAS WILL BE.

FOR TUESDAY AND BEYOND EXPECT SHOWER/THUNDERSTORM CHANCES TO BECOME
INCREASINGLY LIMITED TO THE FAR NORTHERN AREAS AS MOISTURE SLOWLY
PUSHES NORTH INTO CENTRAL NEVADA. TEMPERATURES SHOULD RISE FROM 5-10
DEGREES BELOW NORMAL SUNDAY BACK TOWARDS NORMAL BY MID-WEEK.
&&

.AVIATION...FOR MCCARRAN...WEST/NORTHWEST WIND WILL DECREASE AND GO
LIGHT AND VARIABLE FOR MUCH OF THE MORNING BEFORE GOING MORE
EASTERLY IN THE LATE MORNING AND AFTERNOON. ISOLATED THUNDERSTORMS
WILL BE POSSIBLE THIS AFTERNOON AND EVENING OVER THE SPRING
MOUNTAINS AND THE BEATTY/MORMON MESA CORRIDORS.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...CONSIDERABLY LESS SHOWER AND THUNDERSTORM COVERAGE IS
EXPECTED TODAY OUT WEST WITH ISOLATED STORMS CONFINED TO THE HIGHER
MOUNTAINS OF MAINLY EASTERN NEVADA AND NORTHWEST ARIZONA. SCT-BKN
BASES AROUND 12-15KFT MSL. TYPICAL DIURNAL WIND PATTERNS ARE
EXPECTED TODAY.
&&

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

PIERCE/WOLCOTT

FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:

HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER






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