Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 050358
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
858 PM PDT WED MAY 4 2016

.SYNOPSIS...
AN AREA OF LOW PRESSURE OFF THE CALIFORNIA COAST WILL BRING GUSTY
WINDS ONCE AGAIN TO PARTS OF THE AREA ON THURSDAY. MOISTURE
INCREASES THURSDAY NIGHT WITH SHOWER AND THUNDERSTORM CHANCES
THROUGH THE WEEKEND.
&&

.UPDATE...
WINDS NEVER REALLY MATERIALIZED TO ADVISORY LEVELS TODAY IN THE
OWENS VALLEY, DEATH VALLEY, AND THE SOUTHERN GREAT BASIN, THOUGH
SOME SITES AT LEAST OCCASIONALLY GUSTED 40-45 MPH. WINDS HAVE
NOTICEABLY DECREASED THIS EVENING, SO THE ADVISORY WAS ALLOWED TO
EXPIRE. HI-RES GUIDANCE CONTINUES TO SUGGEST MARGINAL ADVISORY
CRITERIA TOMORROW FOR LINCOLN AND MOHAVE COUNTIES, SO KEPT THE
ADVISORY GOING THERE. MODELS ALSO SUGGEST ABOUT A SIX-HOUR WINDOW
(00Z-06Z FRIDAY) WHERE THE WESTERN MOJAVE DESERT EXCEEDS ADVISORY
CRITERIA. NOT CONFIDENT ENOUGH YET, PARTICULARLY GIVEN THE
RELATIVELY BRIEF DURATION, TO ISSUE AN ADVISORY THERE...BUT WHEN THE
MORE WESTERLY WINDS KICK IN TOMORROW EVENING IN THIS AREA, KDAG AND
KBYS WILL LIKELY GUST AT LEAST OCCASIONALLY TO 40 MPH.

UPDATED GRIDS THIS EVENING BASED ON LATEST RADAR/SATELLITE TRENDS.
WV IMAGERY SHOWS A VORT MAX IN EASTERN CALIFORNIA LIKELY
CONTRIBUTING TO AT LEAST SOME LIGHT SHOWERS CURRENTLY IN THE SIERRA.
HOWEVER, EXPECT MOST OF THIS TO BE OUT OF HERE BY LATE TONIGHT...SO
REDUCED POPS IN THE SOUTHERN SIERRA FROM 06Z ONWARD. HOWEVER, MID
AND HIGH CLOUDS ARE A BIT MORE PREVALENT THAN CURRENT GRIDS REFLECT,
SO BUMPED UP SKY COVER A BIT THROUGH TOMORROW MORNING ACROSS THE
AREA.

CURRENTLY LOOKING AT THE POTENTIAL FOR CONVECTION TOMORROW IN THE
WESTERN CWA. AGREE WITH PREVIOUS SHIFT THE ENVIRONMENT LOOKS
DECENTLY FAVORABLE FOR SCATTERED CONVECTION IN SOUTHEAST CALIFORNIA
AND ADJACENT ESMERALDA/NYE COUNTIES AT THE NOSE OF A MIDLEVEL JET
STREAK AND VORTICITY MAXIMUM EMBEDDED WITHIN THE DEEP CLOSED LOW
APPROACHING THE WEST COAST 00Z FRIDAY. UPPER-LEVEL DIVERGENCE AT THE
NOSE OF A 110+ KT 250-MB JET STREAK COMBINED WITH COLD MIDLEVEL
TEMPERATURES, DIFFERENTIAL HEATING, AND OROGRAPHIC PROCESSES SHOULD
PROVIDE SUFFICIENT LIFT AND INSTABILITY TO BREAK OUT SCATTERED
STORMS DURING THE AFTERNOON AND EVENING HOURS. DEEP-LAYER SHEAR
LOOKS SUPPORTIVE OF SOME STORM ORGANIZATION. COMBINED WITH A WELL-
MIXED BOUNDARY LAYER, MAY SEE SOME SMALL HAIL/GUSTY WINDS WITH ANY
STRONGER CELLS THAT CAN INITIATE.  WILL PASS ALONG THESE CONCERNS TO
THE NEXT SHIFT.
&&

.AVIATION...FOR MCCARRAN...SOUTH WINDS HAVE DECREASED TO AROUND 7-
12 KTS THIS EVENING WITH DIRECTIONS REMAINING CONFINED PRIMARILY TO
160-190. EXPECT THIS TO CONTINUE THIS EVENING, POTENTIALLY WITH
PERIODS OF LIGHT/VARIABLE OR LIGHT DRAINAGE FLOW OVERNIGHT. S/SE
WINDS LOOK TO INCREASE ONCE AGAIN TOMORROW...POTENTIALLY BEING A BIT
STRONGER THAT WHAT WAS OBSERVED TODAY (SPEEDS 10-20 KTS WITH GUSTS
20-30 KTS). MOSTLY SCT-BKN HIGH CLOUDS THROUGH THE PERIOD WITH
MECHANICAL TURBULENCE LIKELY TOMORROW AFTERNOON. ON FRIDAY...AN
APPROACHING STORM SYSTEM WILL BRING SHOWERS AND LOWER CEILINGS TO
THE TERMINAL AREA. RECENT MODEL RUNS SUGGEST DECENT POTENTIAL FOR
THUNDERSTORMS IN THE VALLEY AND ALL FLIGHT CORRIDORS. THIS HAS A
GOOD CHANCE OF CAUSING DELAYS DURING HIGH TRAFFIC PERIODS.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WINDS HAVE GENERALLY SUBSIDED ACROSS THE AREA THIS
EVENING, EXCEPT NEAR KDAG WHERE WSW WINDS HAVE PICKED UP AS
ANTICIPATED EARLY THIS EVENING. THESE SHOULD DIMINISH SOMEWHAT AFTER
MIDNIGHT. EXPECT SOUTH WINDS TO INCREASE AGAIN DURING THE
DAY TOMORROW, ESPECIALLY IN LINCOLN AND MOHAVE COUNTIES, WHERE GUSTS
25-35 KTS ARE POSSIBLE. AN APPROACHING STORM SYSTEM WILL BRING A
CHANCE OF SHOWERS/STORMS AND LOWER CIGS TO SOUTHEAST CALIFORNIA AND
THE SOUTHERN GREAT BASIN DURING THE AFTERNOON/EVENING AND ACROSS THE
ENTIRE AREA ON FRIDAY.
&&

.PREVIOUS DISCUSSION...
312 PM PDT WED MAY 4 2016

.SHORT TERM...THROUGH SATURDAY.

GUSTY WINDS HAVE DEVELOPED IN NORTHWEST PORTIONS OF THE AREA, WITH
WIDESPREAD GUSTS IN THE 30S SO FAR THIS AFTERNOON. GUSTY WINDS ARE
EXPECTED AGAIN TOMORROW ACROSS EASTERN PORTIONS OF THE AREA (MOHAVE
AND LINCOLN COUNTIES). WIND ADVISORY FOR TONIGHT WILL LIKELY BE
ALLOWED TO EXPIRE ON TIME...WITH NO CHANGES MADE TO THE ADVISORY FOR
LINCOLN AND MOHAVE COUNTIES TOMORROW.

AS THE LOW COMES ONSHORE THURSDAY NIGHT, MOISTURE SHOULD BE ON THE
INCREASE. A JET STREAK ROUNDING THE BASE OF THE TROUGH WILL BE
NOSING UP THE COLORADO RIVER VALLEY..PROVIDING LIFT AND SHEAR FROM
ABOUT THE MOJAVE PRESERVE NORTHWARD INTO CENTRAL NYE COUNTY. LIFTED
INDEX VALUES OF AROUND -3C WILL SUPPORT THE CHANCE OF THUNDERSTORMS
THROUGH ABOUT MIDNIGHT FOR THAT REGION. BY FRIDAY AFTERNOON THE
UPPER LEVEL LOW WILL BE ENTERING THE WESTERN CWA WITH PLENTY OF
UPPER LEVEL SUPPORT FOR THUNDERSTORMS OVER MOHAVE CLARK AND LINCOLN
COUNTIES. LIFTED INDEX VALUES OF -3C TO -5C AND BULK SHEAR AROUND 30
KNOTS...EXPECT PLENTY OF THUNDERSTORM POTENTIAL..ESPECIALLY NEAR ANY
MID-LEVEL DRYING OR SHORTWAVES ROTATING THROUGH THE LARGE UPPER
LEVEL LOW. THE UPPER LEVEL LOW SLOWLY TRAVERSES THE AREA...WITH MORE
EMBEDDED SHORTWAVES KEEPING AT LEAST ISOLATED TO SCATTER SHOWERS IN
THE FORECAST THROUGH SATURDAY.

.LONG TERM...SUNDAY THROUGH WEDNESDAY.

WE SHOULD START TO EXPERIENCE A SLIGHT DRYING TREND FROM
SOUTHWEST TO NORTHEAST ON SUNDAY AND EVEN MORE SO ON MONDAY, AS THE
UPPER LOW SLIDES FROM SOUTHERN UTAH TO NORTHEASTERN COLORADO AND
UPPER RIDGING ARRIVES FROM THE WEST. EVEN THOUGH LOWER-LEVEL
MOISTURE WILL LIKELY REMAIN ACROSS SOME AREAS TUESDAY AND PERHAPS
INTO WEDNESDAY, SOUNDINGS INDICATE ENOUGH WARMING ALOFT TO CAP ANY
CONVECTION. THE TEMPERATURE ROLLER COASTER WILL CONTINUE THROUGH THE
FORECAST PERIOD, AS WE GO FROM 5-10 DEGREES BELOW NORMAL FRIDAY
THROUGH SATURDAY TO ABOVE NORMAL WEDNESDAY IF NOT TUESDAY.
&&

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

$$

UPDATE/AVIATION...SHAFER
SHORT TERM...STEELE
LONG TERM...PADDOCK

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