Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 052301
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
301 PM PST THU MAR 5 2015

.SYNOPSIS...DRY AND MILD WEATHER IS EXPECTED TO CONTINUE ACROSS THE
AREA THROUGH TUESDAY NIGHT. A STORM SYSTEM MAY IMPACT THE AREA
WEDNESDAY INTO THURSDAY NIGHT WITH INCREASED CLOUDS AND A FEW
SHOWERS.
&&

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT.

THE REX BLOCK IS BACK AS IT WILL SET UP TONIGHT AND LAST THROUGH
SATURDAY NIGHT. HIGH PRESSURE ALOFT WILL REMAIN CENTERED OVER NORCAL
WITH A MID/UPPER LEVEL LOW CENTERED NEAR SOCAL THAT WILL EVENTUALLY
DRIFT EAST TOWARD ARIZONA BY SATURDAY NIGHT. DESPITE THE LOW BEING
NEARBY, THERE IS NO MOISTURE TAP INTO OUR AREA. THUS DRY CONDITIONS
WILL CONTINUE WITH A FEW HIGH CLOUDS AROUND AT BEST. SINKING AIR
COURTESY OF THE HIGH WILL RESULT IN A WARMING TREND EACH DAY THROUGH
SUNDAY. ONCE THE LOW GETS INTO ARIZONA IT SHOULD GET PUSHED EAST BY
ENERGY DROPPING ACROSS THE INTERMOUNTAIN WEST. WE USED A BLEND OF
GUIDANCE FOR HIGH TEMPS WHICH PLACED US GENERALLY IN THE MIDDLE OF
THE ROAD WITH OUR FORECAST NUMBERS.

THE ONLY ISSUE OF CONCERN WILL BE NORTHERLY WINDS MAINLY IN THE
COLORADO RIVER VALLEY. NORTH-SOUTH SURFACE PRESSURE GRADIENTS WILL
REMAIN TIGHT ENOUGH THROUGH SATURDAY TO SUPPORT GUSTS OF 20-30 MPH
MAINLY IN THE AFTERNOON AND EVENING TOMORROW AND TO A LESSER EXTENT
ON SATURDAY. BY SATURDAY NIGHT THESE GRADIENTS SHOULD RELAX ENOUGH
TO ALLOW FOR LESS IN THE WAY OF WIND ON SUNDAY.

.LONG TERM...MONDAY THROUGH THURSDAY NIGHT.

MARVELOUS MARCH WEATHER WILL LAST THROUGH THE MIDDLE OF NEXT WEEK AS
THE HIGH ALOFT SHIFTS INLAND OVER THE SOUTHWEST MONDAY INTO TUESDAY.
THERE MAY BE A TOUCH OF COOLING ON MONDAY IN RESPONSE TO A PIECE OF
ENERGY THAT DROPS BY TO OUR EAST SUNDAY NIGHT.

BY WEDNESDAY AN INCOMING MID/UPPER LEVEL TROUGH WILL PUSH THE HIGH
OFF TO THE EAST. THIS SHOULD BE THE WARMEST DAY OF THE WEEK IN MOST
SPOTS AS SOUTHWEST FLOW INCREASES AHEAD OF THE TROUGH AND WE GET
GOOD MIXING. WE MAY SEE WIND GUSTS OF 25-35 MPH ACROSS THE AREA,
HOWEVER, THE GFS DOES NOT SHOW MUCH MORE THAN A 70 KT JET CROSSING
THE AREA AT 250 MB THEN WHICH IS NOT ALL THAT STRONG FOR THIS TIME
OF THE YEAR. THERE ARE SOME TIMING DIFFERENCES WITH SWINGING THE
TROUGH ON THROUGH AS WELL AS MODEL DIFFERENCES IN HOW THEY HANDLE
THE SYNOPTIC PATTERN. THE 12Z OPERATIONAL GFS AND GEM KEEP THE
TROUGH AS AN OPEN WAVE WHILE THE 12Z OPERATIONAL ECMWF CLOSES ENERGY
OFF INTO A DEFINED MID/UPPER LEVEL LOW. FOR NOW, I HAVE GONE MORE
WITH MORE PROGRESSIVE GFS/GEM WHICH WOULD MAINLY BRING A FEW SHOWERS
TO THE SOUTHERN GREAT BASIN AND AN INCREASE IN CLOUDS TO THE REST OF
THE AREA. TEMPS SHOULD COOL AT LEAST 5-7 DEGREES IF WE SEE JUST AN
OPEN WAVE PASS THROUGH BUT COULD BE COOLER IF THE ECMWF SOLUTION
VERIFIES.
&&

.AVIATION...FOR MCCARRAN...WINDS WILL BE 8 KTS OR LESS AND TREND
TOWARD TYPICAL DIURNAL WIND SHIFTS UNDER A RELATIVELY CLEAR SKY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ALONG THE COLORADO RIVER NEAR KIFP AND KEED NORTHERLY
WINDS IN THE 10-20 KT RANGE WITH GUSTS TO 25 KTS ARE EXPECTED AGAIN
AFTER 17Z OR SO FRIDAY THROUGH 03Z OR SO SATURDAY.  LIGHT WINDS
FAVORING TYPICAL DIURNAL WIND PATTERNS ARE EXPECTED ELSEWHERE. A
RELATIVELY CLEAR SKY IS FORECAST THROUGH FRIDAY.
&&

.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED
THROUGH THE WEEKEND.
&&

$$

STACHELSKI

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