000
FXUS65 KVEF 190516
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1015 PM PDT THU MAR 18 2010
.SYNOPSIS...A LOW PRESSURE SYSTEM MOVING RAPIDLY ACROSS SOUTHERN
NEVADA AND THE MOJAVE DESERT WILL HEAD ACROSS SOUTHWEST ARIZONA
EARLY FRIDAY MORNING. GUSTY NORTH WINDS WILL LINGER THROUGH MUCH OF
FRIDAY...ESPECIALLY DOWN THE COLORADO RIVER VALLEY. COOLER
TEMPERATURES WILL OCCUR FRIDAY AND SATURDAY BEFORE WARMING TAKES
PLACE SUNDAY AND MONDAY.
&&
.UPDATE...THE COLD FRONT EXTENDED FROM BARSTOW ACROSS FAR SOUTHERN
NEVADA AND UP THROUGH NORTHWEST ARIZONA AT 0430Z. WINDS HAVE
DIMINISHED SIGNIFICANTLY OVER SOUTHERN NEVADA BEHIND THE FRONT AND
THE WIND ADVISORY HAS BEEN CANCELLED FOR SOUTHERN NYE...CENTRAL AND
SOUTHERN CLARK COUNTIES. THE UPPER LEVEL VORT WAS DROPPING DOWN
THROUGH INYO COUNTY WITH LIGHT TO MODERATE CURRENTLY ACROSS MUCH OF
OF NORTHERN SAN BERNARDINO AND CLARK COUNTIES. THE 00Z NAM AND GFS
IDENTIFIED THIS FEATURE WELL AND TAKE IT ACROSS SOUTHEAST
CALIFORNIA AND YUMA BETWEEN 06Z AND 12Z. THIS SHOULD CONTINUE TO
GENERATE SCATTERED SHOWERS ACROSS SAN BERNARDINO COUNTY OVERNIGHT
AND ISOLATED SHOWERS OVER FAR SOUTHERN NEVADA AND NORTHWEST ARIZONA.
WIND GUSTS WERE REACHING UP TO 50 MPH OVER SAN BERNARDINO COUNTY
WITH THE COLD FRONT BUT SPEEDS SHOULD DROP BELOW 40 MPH IN AN HOUR
OR TWO AND WILL HANDLE WITH SHORT TERM FORECASTS. A FORECAST UPDATE
WILL BE OUT SHORTLY TO ADDRESS THE OVERNIGHT TRENDS. AFTER 12Z...
THE MAIN ISSUE WILL BE NORTH WINDS DOWN THE COLORADO RIVER VALLEY
AND THE WIND ADVISORY WILL REMAIN IN EFFECT FOR THOSE ZONES FRIDAY.
-ADAIR-
&&
.AVIATION...FOR MCCARRAN...A STRONG COLD FRONT PUSHED THROUGH THE
LAS VEGAS VALLEY THIS EVENING AND IS NOW PUSHING SOUTH OF THE AREA.
STRONG NORTH WINDS WILL BE PREVALENT OVERNIGHT AND INTO THE MORNING
HOURS WITH WINDS 15-25KTS AND GUSTS MAY REACH 35KTS AT TIMES. A FEW
ISOLATED SHOWERS ARE POSSIBLE THROUGH 10Z WITH CEILINGS AROUND 10K
FEET. NORTHERLY WINDS WILL GRADUALLY DIMINISH DURING THE AFTERNOON
HOURS ON FRIDAY...WITH FURTHER REDUCTION DOWN TO 10 KTS OR LESS BY
FRIDAY EVENING.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...A COLD FRONT IS MOVING SOUTH THROUGH MOHAVE AND
SOUTHERN SAN BERNARDINO COUNTIES TONIGHT. SCATTERED SHOWERS AND
GUSTY WINDS WILL CONTINUE FOR THE NIGHT ALONG WITH CEILINGS AROUND
10K MSL. THERE MAY EVEN BE AN ISOLATED THUNDERSTORM. WINDS SPEED OF 20
TO 30 MPH WILL BE COMMON OVERNIGHT WITH STRONGER WINDS DEVELOPING
DOWN THE COLORADO RIVER VALLEY BY MORNING. GUSTY NORTH WINDS WILL
OCCUR AND PERSIST THROUGHOUT THE DAY ON FRIDAY. THE COLORADO RIVER
VALLEY WILL EXPERIENCE THE STRONGEST WINDS FRIDAY WITH GUSTS TO
ABOUT 45 KNOTS MOST OF THE DAY FRIDAY. -CZYZYK-
&&
.PREV DISCUSSION.../313 PM PDT THU MAR 18 2010/
.SHORT TERM...BASED ON SATELLITE AND SURFACE OBSERVATIONS COLD FRONT
RUNS FROM NEAR TONOPAH TO ELY. SO FAR...PRECIPITATION HAS BEEN VERY
LIGHT AND CONFINED TO CENTRAL AND EAST CENTRAL NEVADA. AS FRONT
SLIDES SOUTHEAST THIS EVENING IT WILL ENCOUNTER DRIER AIR OVER
SOUTHERN NEVADA WHICH WILL LIMIT SHOWERS MAINLY TO THE HIGHER
TERRAIN. DID LEAVE A SLIGHT CHANCE IN FOR LAS VEGAS BUT CONFIDENCE
WANING AND WOULD EXPECT SPRINKLES AT MOST. LITTLE HAS CHANGED ON THE
TIMING OF THE COLD FRONT WITH PASSAGE THROUGH LAS VEGAS AROUND 8 PM
(+/- 1 HOUR) AND EVENTUALLY CLEARING OUR CWA BY 2 AM FRIDAY. AFTER
FURTHER CONSIDERATION HAVE BUMPED UP THE START OF OUR WIND ADVISORY
FOR THE LAKE MEAD NATIONAL RECREATION AREA SOUTH TO LAKE HAVASU CITY
TO RUN FROM 7 AM TO 6 PM FRIDAY. THE SURFACE PRESSURE GRADIENT AND
SUPPORT ALOFT START WEAKENING FRIDAY NIGHT AS HIGH PRESSURE BUILDS
IN FROM THE WEST. RIDGE TRANSITIONS EAST ACROSS THE INTERMOUNTAIN
WEST SATURDAY AND SUNDAY. NEXT TROUGH BEGINS TO ENTER THE PICTURE
SUNDAY NIGHT.
.LONG TERM...A BIT OF SWINGING BACK AND FORTH BY THE EURO...BUT IT
IS NOW MORE IN LINE WITH THE GFS IN HANDLING THE NEXT SYSTEM MONDAY
THROUGH WEDNESDAY. THE IDEA OF A CLOSED LOW DROPPING OVER NEVADA IS
NOT THERE...THOUGHT THE GEM AND DGEX CONTINUE THIS...AND KEEPING THE
NORTHERN BRANCH TROUGH FURTHER NORTH. THE SOUTHERN PART OF THE SPLIT
IS STILL EXPECTED TO FAR ENOUGH SOUTH TO NOT BE A FACTOR. WITH A
MORE NORTHERLY TRACK MOST MOISTURE WILL STAY NORTH OF THE FORECAST
AREA. I HAVE KEPT IN THE POPS FOR OUR NORTHERN ZONES FOR TUESDAY AND
WEDNESDAY AS DYNAMICS SHOULD BE ENOUGH TO PRODUCE SOME
PRECIPITATION. THE POPS MAY NEED TO BE LOWERED IF THE TRACK STAYS OR
SHIFTS FURTHER NORTH. THE BIGGEST IMPACTS OF WILL BE WINDS AND
TEMPERATURES TUESDAY AND WEDNESDAY. WINDS WILL BE STRONGEST POST
FRONTAL. DID LOWER THE SPEEDS A LITTLE AS THE TRACK IS FURTHER NORTH
AND HENCE GRADIENTS ARE NOW EXPECTED TO BE LOWER. WIND ADVISORY
LEVEL WINDS ARE POSSIBLE...ESPECIALLY IN OUR RIVER ZONES LATE
TUESDAY AND WEDNESDAY. TEMPERATURES WILL DROP BEHIND THE FRONT TO
BELOW NORMAL LEVELS WEDNESDAY AND SHOULD REBOUND THE REST OF THE
WEEK AS RIDGING BUILDS IN THROUGH THE REST OF THE WEEK.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...WIND ADVISORY FROM 7 AM TO 6 PM PDT FRIDAY FOR NVZ021.
AZ...WIND ADVISORY FROM 7 AM TO 6 PM MST FRIDAY FOR AZZ002-036.
CA...WIND ADVISORY FROM 7 AM TO 6 PM PDT FRIDAY FOR CAZ527.
&&
$$
PIERCE/JACQUES
HTTP://WEATHER.GOV/LASVEGAS
