Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 291531
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
830 AM PDT FRI APR 29 2016

.SYNOPSIS...ACTIVE WEATHER PATTERN WILL CONTINUE WITH ANOTHER
WEATHER SYSTEM SET TO BRING SHOWERS AND THUNDERSTORMS TO THE REGION
OVER THE WEEKEND. TEMPERATURES WILL REMAIN COOLER THAN NORMAL UNTIL
A WARMING TREND COMMENCES NEXT WEEK AS THINGS DRY OUT. ANOTHER
WEATHER SYSTEM WILL APPROACH LATE IN THE WEEK BRINGING A COOLING
TREND AND AN INCREASE IN CLOUD COVER...WITH SOME SHOWER ACTIVITY
POSSIBLE.

&&

.UPDATE...THE INHERITED FORECAST LOOKS TO BE IN PRETTY GOOD SHAPE
AND THE OVERALL THINKING REMAINS UNCHANGED. HOWEVER...SATELLITE AND
LATEST MODEL DATA INDICATE A BIT MORE CLOUD COVER TODAY THAN WHAT
THE INHERITED GRIDS INDICATED. SO I BUMPED UP THE SKY COVER FOR
TODAY AND THIS EVENING. -HARRISON-
&&

.PREV DISCUSSION...
240 AM PDT FRI APR 29 2016

.SHORT TERM...THROUGH SUNDAY NIGHT.

UNUSUALLY ACTIVE SPRING WEATHER PATTERN WILL CONTINUE THROUGH THE
WEEKEND WITH YET ANOTHER CLOSED LOW DROPPING SOUTH INTO OUR AREA.
EXPECT MORE WET ROADS...HIGH MOUNTAIN SNOW...AND THUNDERSTORM
ACTIVITY.

IN THE MEANTIME...IMPROVED CONDITIONS ARE EXPECTED FRIDAY WITH
PARTLY CLOUDY SKIES. THERE WILL BE SOME TERRAIN DRIVEN CUMULUS BUILD
UPS NEAR THE MOUNTAINS...AND EVEN A FEW ISOLATED SHOWERS AND STORMS
MAY BREAK OUT IN THE MOUNTAINS OF MOHAVE AND LINCOLN
COUNTIES...PERHAPS THE SPRING MOUNTAINS AS WELL. BUT THE COVERAGE
WILL BE VERY ISOLATED.  TEMPERATURES TOMORROW WILL WARM SEVERAL
DEGREES ABOVE THURSDAYS HIGHS...BUT STILL AVERAGE 2 TO 6 DEGREES
BELOW LATE APRIL NORMALS.

ATTENTION WILL THEN SHIFT UPSTREAM AS AN ENERGETIC SHORT WAVE DIVES
SOUTHWARD AND CLOSES OFF NORTH OF RENO. AS THIS SYSTEM DIVES INTO
THE SOUTHERN GREAT BASIN LATE TONIGHT INCREASING SHOWERS AND
THUNDERSTORMS WILL BREAK OUT NORTH OF INTERSTATE 15 SUPPORTED BY
FAVORABLE JET DYNAMICS AND A DEVELOPING SURFACE LOW. GUIDANCE
SUGGESTS A CONCENTRATED BAND OF PRECIPITATION FORMING JUST NORTH OF
THE I-15 CORRIDOR FROM SOUTHERN LINCOLN COUNTY SOUTHWESTWARD TOWARDS
THE SPRING MOUNTAINS BY SUNRISE SATURDAY. ADDITIONAL SHOWERS AND
STORMS ARE LIKELY TO FORM BENEATH THE CLOSED LOW BY MID MORNING
THANKS TO CHILLY 500 MB TEMPS OF -20C OR COLDER.  THE COMBINATION OF
STRONG DYNAMICS AND MARGINAL TO MODERATE INSTABILITY BENEATH A VERY
COLD CORE ALOFT FOR LATE APRIL MAKE THIS SYSTEM LIKELY TO PRODUCE AT
LEAST A FEW STRONG STORMS SATURDAY AFTERNOON.  GUSTY WINDS...SMALL
HAIL TO THE SIZE OF DIMES...AND EVEN A COLD AIR FUNNEL CLOUD WILL BE
POSSIBLE THE STRONGER ACTIVITY WHICH DEVELOPS.  THESE STORMS WILL BE
MOST FAVORED ACROSS OUR DESERTS AND MOHAVE COUNTY WHERE INSTABILITY
WILL BE THE GREATEST.  INSTABILITY MAY BE TEMPERED SOMEWHAT BY
CLOUDS AND RAINFALL EARLY IN THE DAY ACROSS THE LAS VEGAS
VALLEY...BUT THE POTENTIAL IS STILL THERE FOR SOME MORE STORMY
WEATHER.

IN ADDITION TO THE WIDESPREAD RAIN AND THUNDERSTORMS...MOUNTAIN
SNOWFALL CAN BE EXPECTED ABOVE 6500 FEET. LIGHT AND SLUSHY
ACCUMULATIONS OF 1 TO 2 INCHES ARE POSSIBLE NEAR MOUNT CHARLESTON
LODGE BY SATURDAY MORNING...WITH SEVERAL INCHES LIKELY ABOVE THE
8500 FOOT LEVEL. LIGHTER AMOUNTS EXPECTED IN THE SIERRA BUT A COUPLE
OF INCHES WILL BE POSSIBLE THERE AS WELL ABOVE 7000 FEET.  GUSTY
NORTH WINDS AND POCKETS OF BLOWING DUST WILL ALSO DEVELOP ACROSS
INYO COUNTY SATURDAY AFTERNOON.

THE CLOSED LOW WILL BEGIN TO PUSH EASTWARD SATURDAY EVENING WITH
SHOWERS TAPERING OFF FROM WEST TO EAST OVERNIGHT.  RESIDUAL
MOISTURE AND INSTABILITY WILL MEAN ANOTHER CHANCE OF SHOWERS AND
STORMS SUNDAY AFTERNOON...BUT COVERAGE WILL BE MORE SCATTERED.
TEMPERATURES WILL BE COLDEST SATURDAY WITH WIDESPREAD SHOWERS AND
STORMS AROUND...AVERAGING 10 TO 15 DEGREES BELOW NORMAL. WITH
TEMPERATURES REBOUNDING SLIGHTLY BUT REMAINING COOL ON SUNDAY.


.LONG TERM...MONDAY THROUGH FRIDAY.

IT LOOKS LIKE WE WILL SEE A DRYING AND WARMING TREND ACROSS MUCH OF
THE FORECAST AREA THE FIRST HALF OF THE WEEK UNDER A RIDGE OF HIGH
PRESSURE THEN A LARGE EASTERN PACIFIC CLOSED LOW IS FORECAST TO MOVE
INLAND THURSDAY AND FRIDAY FOR A RETURN OF UNSETTLED WEATHER. THE
MEDIUM RANGE MODELS ARE ALL IN QUITE GOOD AGREEMENT INTO NEXT
WEEKEND AND CONFIDENCE IS MODERATE TO HIGH IN THE SYNOPTIC PATTERN.

AS THE WEEKEND SYSTEM EXITS...MONDAY WILL SEE SUFFICIENT LINGERING
MOISTURE AND INSTABILITY FOR SOME SHOWERS OVER SOUTHEAST NEVADA AND
NORTHWEST ARIZONA AND EVEN A SLIGHT CHANCE OF THUNDERSTORMS IN
LINCOLN AND NORTHERN MOHAVE COUNTIES. THE RIDGE AXIS THEN MOVES OVER
THE REGION TUESDAY AND SLOWLY MOVES TO THE EAST WEDNESDAY AHEAD OF
THE LARGE EASTERN PACIFIC TROUGH THAT EVENTUALLY SPINS UP INTO A
BROAD CLOSED CIRCULATION OFF THE CALIFORNIA COAST. THE RIDGE IS
ACTUALLY HIGHLY AMPLIFIED AND EXTENDS FROM THE SOUTHWEST STATES ALL
THE WAY UP THROUGH WESTERN CANADA. THIS WILL LEAD TO TEMPERATURES
CLIMBING WELL ABOVE NORMAL WEDNESDAY INTO THURSDAY WITH INCREASING
SOUTHERLY FLOW BEFORE HEIGHTS FALL WITH THE INCOMING SYSTEM AND
MOISTURE BEGINS TO SPREAD FROM WEST TO EAST THURSDAY AND FRIDAY.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVER NORTHERN INYO COUNTY
THURSDAY THEN CHANCES FOR SHOWERS WILL SPREAD INTO ZONES WEST AND
NORTH OF LAS VEGAS BY FRIDAY WITH THE SYSTEM FORECAST TO SLOWLY MAKE
ITS WAY ACROSS THE DESERT SOUTHWEST NEXT WEEKEND.

&&

.AVIATION...FOR MCCARRAN...LIGHT AND VARIABLE WINDS EXPECTED THROUGH
MIDDAY WITH JUST FEW-SCT CLOUDS NEAR 10K FT. STRONGER WEST-SOUTHWEST
WINDS WILL PUSH INTO THE AIRFIELD BETWEEN 22-00Z IN THE 9-12KT
RANGE. INCREASING CLOUDS EXPECTED OVERNIGHT BUT CIGS SHOULD REMAIN
ABOVE 10K THROUGH 12Z. CIGS MAY FALL TO 6K OR LOWER AFTER 12Z
SATURDAY WITH SHOWERS DEVELOPING ACROSS THE VALLEY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...PARTLY CLOUDY SKIES EXPECTED IN MOST AREAS WITH SOME
SCATTERED CLOUDS FAVORED NEAR REGIONAL TERRAIN FEATURES. A FEW
ISOLATED SHOWERS POSSIBLE IN MOHAVE COUNTY AND THE SOUTHERN GREAT
BASIN. OTHERWISE GENERALLY LIGHT WINDS FOR MOST AREAS. STRONGER WEST
WINDS WILL DEVELOP LATE IN THE DAY ACROSS THE WESTERN MOJAVE DESERT
WITH KDAG LIKELY SEEING GUSTS TO 30KTS AFTER 00Z. INCREASING CLOUDS
EXPECTED TONIGHT WITH SHOWERS AND THUNDERSTORMS DEVELOPING NORTH OF
THE I-15 CORRIDOR LATE IN THE NIGHT.

&&

.SPOTTER INFORMATION STATEMENT...ACTIVE WEATHER IS EXPECTED OVER
THE WEEKEND.  SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT
WEATHER ACCORDING TO STANDARD OPERATING PROCEDURES.
&&

$$

SHORT TERM/AVIATION...OUTLER
LONG TERM...ADAIR

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