Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 250312
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
812 PM PDT THU APR 24 2014

.SYNOPSIS...A LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION FRIDAY
AND SATURDAY BRINGING GUSTY WINDS...A GOOD CHANCE OF RAIN AND
MOUNTAIN SNOW SHOWERS...AND MUCH COOLER TEMPERATURES. DRY AND WARMER
WEATHER CAN BE EXPECTED SUNDAY THROUGH TUESDAY AS HIGH PRESSURE
BUILDS IN FROM THE WEST.
&&

.UPDATE...TRENDS THIS EVENING LOOK GOOD...AS DO THE WIND AND FIRE
WEATHER HEADLINES FOR TOMORROW. ONLY CHANGE AT THIS TIME WILL BE TO
CORRECT THE W/W/A SECTION FROM PREVIOUS AFD.
&&

.PREV DISCUSSION...
250 PM PDT THU APR 24 2014

.SHORT TERM...THROUGH SATURDAY NIGHT...

CLOUDS STARTING TO INCREASE OVER THE FAR NORTHWEST PORTIONS OF THE
CWA AHEAD OF A DEEPENING LOW PRESSURE SYSTEM THAT WILL BRING
SIGNIFICANT CHANGES TO THE WEATHER STARTING FRIDAY. INITIALLY WE
WILL SEE AN INCREASE IN SOUTHWEST WINDS LATE FRIDAY MORNING WITH
MOST AREAS SEEING ADVISORY LEVELS WINDS BY THE AFTERNOON. MOST
LOCATIONS WILL SEE GUSTS BETWEEN 40-50 MPH...BUT A FEW SITES
ESPECIALLY ACROSS SAN BERNARDINO COUNTY MAY SEE GUSTS OVER 55 MPH.
CURRENT WIND ADVISORIES LOOK GOOD AND NO CHANGES NEEDED. OVERALL THE
MODELS REMAIN IN GOOD AGREEMENT WITH THE TRACK AND DEPTH OF THIS
SYSTEM AND GENERALLY ONLY MADE SOME MINOR TWEAKS TO THE FORECAST.
PRECIPITATION IS FORECAST TO MOVE INTO THE SIERRA FRIDAY
AFTERNOON...BUT LITTLE IF ANY IS EXPECTED TO SPILL OVER ONTO THE
EASTERN SLOPE UNTIL FRIDAY EVENING. THE LOW IS FORECAST TO GET WOUND
UP AND DEEPEN JUST OFF THE CENTRAL CALIFORNIA COAST BEFORE MOVING
INLAND ACROSS SOUTHERN CALIFORNIA LATE FRIDAY NIGHT INTO SATURDAY
MORNING. STRONG AREA OF UPPER DIFFLUENCE AHEAD OF THE LOW WILL HELP
GENERATE SHOWERS ACROSS MAINLY THE EASTERN HALF OF THE CWA FRIDAY
NIGHT...ESPECIALLY ACROSS LINCOLN AND MOHAVE COUNTIES WHERE OVER A
HALF AN INCH OF PRECIPITATION IS POSSIBLE. LESSER AMOUNTS ACROSS
CLARK AND EASTERN SAN BERNARDINO COUNTIES...BUT UP TO 2 TENTHS OF AN
INCH OF RAINFALL IS NOT OUT OF THE QUESTION. DID UP THE POP AND QPF
AMOUNTS ACROSS THE EASTERN HALF OF THE CWA. SNOW LEVELS WILL START
OUT AROUND 8000 FEET AND THEN FALL TO AROUND 5500 FEET BY SATURDAY
MORNING. LOCATIONS BETWEEN 6000-7000 FEET COULD SEE UP TO 3 INCHES
OF SNOW WITH HIGHER AMOUNTS ABOVE THAT. HOWEVER...AT THIS TIME FEEL
THAT THE GREATEST THREAT OF SIGNIFICANT SNOW AMOUNTS WILL BE HIGH
ENOUGH NOT TO AFFECT TRAVEL AND HAVE ELECTED NOT TO ISSUE ANY WINTER
WEATHER PRODUCTS. A COLD FRONT IS ALSO EXPECTED TO MOVE THROUGH THE
CWA FRIDAY EVENING AND THEN ACROSS THE CWA BY MID DAY SATURDAY WHICH
IS EXPECTED TO USHER IN MUCH COOLER TEMPERATURES. TEMPERATURES ON
SATURDAY ARE EXPECTED TO DROP AROUND 20 DEGREES FROM FRIDAYS HIGHS.
BREEZY CONDITIONS ARE LIKELY BEHIND THE FRONT AND SCATTERED SHOWERS
AND MOUNTAIN SNOW SHOWERS WILL AGAIN BE POSSIBLE ALONG THE FRONT. BY
SATURDAY AFTERNOON THE UPPER LOW IS FORECAST TO BE OVER EASTERN
ARIZONA...BUT SOME WRAP AROUND PRECIPITATION WILL STILL BE POSSIBLE
ACROSS LINCOLN AND MOHAVE COUNTIES. PRECIPITATION IS EXPECTED TO END
BY SATURDAY EVENING.

.LONG TERM...SUNDAY THROUGH THURSDAY NIGHT.

NORTHWEST FLOW ALOFT IS EXPECTED TO SET UP ON SUNDAY BEHIND THE
DEPARTING SYSTEM AND A RIDGE ALOFT CENTERED OFFSHORE. MID-LEVEL
ENERGY RIPPLING THROUGH THE FLOW COMBINED WITH ENOUGH MOISTURE
SHOULD KEEP ENOUGH CLOUDS AROUND TO WARRANT PARTLY CLOUDY CONDITIONS
ACROSS THE NORTHERN CWFA. BY MONDAY, SUNSHINE SHOULD BECOME MORE
DOMINANT AS DRIER AIR ALOFT WORKS IN. ENERGY DROPPING DOWN THE EAST
SIDE OF THE RIDGE ON TUESDAY AND POTENTIALLY INTO WEDNESDAY SHOULD
HELP TO ENHANCE NORTH WINDS ACROSS THE EASTERN PORTIONS OF OUR AREA
ESPECIALLY IN THE COLORADO RIVER VALLEY. LAKE WIND ADVISORY CRITERIA
COULD VERY WELL BE MET ON TUESDAY AND MAYBE EVEN WEDNESDAY.

TEMPS SHOULD BE 5-8 DEGREES BELOW NORMAL ON SUNDAY THEN WARM TO NEAR
NORMAL ON MONDAY AS HEIGHTS RISE FURTHER. FROM TUESDAY ONWARD THE
FORECAST BECOMES MORE UNCERTAIN WITH TEMPS AS THE GFS AND GEM BUILD
THE RIDGE INLAND FURTHER WHILE THE ECMWF KEEPS THE CENTER OF IT
OFFSHORE. AT THE PRESENT THE FORECAST LEANS TOWARD A BLEND OF THE
COOLER ECMWF AND THE WARMER GFS/GEM. THUS ANY WARMING TREND THROUGH
THE WEEK WILL BE BASED ON THE POSITION OF THE RIDGE.

.FIRE WEATHER...ANOTHER ROUND OF STRONG WINDS IS EXPECTED OVER THE
AREA FRIDAY AFTERNOON AND EVENING WITH WIDESPREAD SOUTHWEST WINDS
GUSTING OVER 35 MPH. RELATIVE HUMIDITY WILL BE CLOSE TO OR BELOW 15
PERCENT FOR AT LEAST A PORTION OF THE DAY OVER THE LOWER ELEVATIONS
ACROSS MUCH OF SOUTHERN NEVADA AND NORTHWEST ARIZONA. THE FIRE
WEATHER WATCH HAS BEEN UPGRADED TO A RED FLAG WARNING FROM 11 AM TO
8 PM FRIDAY.

.AVIATION...FOR MCCARRAN...SOUTH WINDS MAINLY 4-8 KTS EARLY THIS
MORNING WILL LIKELY BECOME EAST/SOUTHEAST BY LATE MORNING WITH
SPEEDS UNDER 10 KTS. WINDS WILL BECOME SOUTH/SOUTHWEST AROUND 10 KTS
AFTER ABOUT 23Z AND REMAIN THERE ALL NIGHT. MAINLY HIGH CLOUDS AOA
20K FEET THROUGH TONIGHT. STRONG SOUTHWESTERLY WINDS ARE EXPECTED
FRIDAY AFTERNOON ALONG WITH LOWERING CLOUDS AND A RISK OF SHOWERS
MAINLY IN THE BEATTY CORRIDOR.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...NO OPERATIONALLY SIGNIFICANT WEATHER IS EXPECTED TODAY
WITH WINDS GENERALLY LESS THAN 10 KTS IN THE MORNING AND THE AROUND
10-15 KTS OUT OF THE SOUTHWEST IN THE AFTERNOON. A STORM SYSTEM WILL
BRING INCREASING SOUTHWEST WINDS AREAWIDE ON FRIDAY ALONG WITH
LOWERING CEILINGS AND INCREASING PRECIP CHANCES TO AREAS WEST AND
NORTH OF LAS VEGAS.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...WIND ADVISORY FROM 11 AM TO 11 PM PDT FRIDAY FOR NVZ014>022.
     RED FLAG WARNING FROM 11 AM TO 8 PM PDT FRIDAY FOR
     NVZ461-462-465-466.
AZ...WIND ADVISORY FROM 11 AM TO 11 PM MST FRIDAY FOR AZZ001-003-036.
     RED FLAG WARNING FROM 11 AM TO 8 PM MST FRIDAY FOR AZZ101-102.
CA...WIND ADVISORY FROM 11 AM TO 11 PM PDT FRIDAY FOR CAZ519>525.
     RED FLAG WARNING FROM 11 AM TO 8 PM PDT FRIDAY FOR CAZ229.
&&

$$

MORGAN/ASG/STACHELSKI

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