000 
FXUS65 KVEF 161655
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
955 AM PDT WED APR 16 2008

.SYNOPSIS...COOL AND BREEZY CONDITIONS EXPECTED TODAY ACROSS THE 
SOUTHERN GREAT BASIN AND MOJAVE DESERT BEFORE HIGH PRESSURE BRIEFLY 
BUILDS OVER THE AREA WITH ABOVE NORMAL TEMPERATURES BY FRIDAY. A 
LARGE LOW PRESSURE SYSTEM IS THEN FORECAST TO DROP INTO THE WESTERN 
STATES LATE IN THE WEEKEND AND EARLY NEXT WEEK FOR ANOTHER ROUND OF 
COOL AND WINDY WEATHER.
&&

.UPDATE...A TIGHT NORTH/SOUTH SURFACE PRESSURE GRADIENT OVER THE 
FORECAST AREA /11MB BETWEEN TONOPAH AND KINGMAN/ IS RESULTING IN 
CONTINUED STRONG NORTHERLY WINDS ACROSS SOUTHERN NEVADA AND 
NORTHWEST ARIZONA...JUST BELOW ADVISORY CRITERIA IN SOME AREAS. BY 
THIS AFTERNOON...THE TIGHT GRADIENT COMBINED GOOD MID/UPPER LEVEL 
SUPPORT SHOULD RESULT IN ADVISORY LEVEL WINDS ALONG THE COLORADO 
RIVER VALLEY. THE CURRENT FORECAST DEPICTS THIS WELL AND NO UPDATE 
WILL BE NEEDED THIS MORNING. WILL NEED TO MONITOR WINDS ACROSS 
MOHAVE COUNTY THIS AFTERNOON...THINKING IF THE GRADIENT INCREASES 
MORE THAN PROGGED...ADVISORY LEVEL WINDS WILL BE POSSIBLE FOR A 
SHORT DURATION THERE AS WELL.
&&

.AVIATION...FOR MCCARRAN...EXPECT NORTH WINDS WITH GUSTS IN THE 
20-30 KT RANGE THROUGH 23Z WITH A FURTHER DECREASE THROUGH THE EARLY 
EVENING. AFTER 03Z NORTH WINDS ARE EXPECTED TO BE AROUND 10-15 
KNOTS. SKIES WILL REMAIN MOSTLY CLEAR. 

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST 
CALIFORNIA...GENERALLY NORTHWEST TO NORTH WINDS ACROSS THE AREA 
TODAY WITH SPEEDS IN THE 20-30 KNOT RANGE. STRONGER WINDS WILL OCCUR 
THIS AFTERNOON DOWN THE COLORADO RIVER WITH SPEEDS BETWEEN 30-35 
KNOTS. WINDS ACROSS THE AREA ARE EXPECTED TO DIMINISH AFTER 00Z THIS 
EVENING WITH NORTH WINDS AROUND 10-15 KNOTS. 

&&
.SHORT TERM...COLD FRONT HAS EXITED THE CWA AS OF 2 AM PDT. NORTH 
WINDS CONTINUE TO PLAGUE THE SOUTHERN PORTION OF NEVADA AND THE 
OWENS VALLEY EARLY THIS MORNING...BUT WINDS HAVE GENERALLY DROP 
BELOW ADVISORY CRITERIA. HOWEVER NORTH/SOUTH SURFACE GRADIENTS AND 
NORTHERLY FLOW IN THE LOWER LEVELS PROMISE GUSTY WINDS FORMING BY 
MID MORNING OVER THE COLORADO RIVER VALLEY AND WILL ISSUE AN 
ADVISORY FOR THIS MORNING THROUGH THE AFTERNOON. OTHER AREAS WILL BE 
BREEZY/WINDY...BUT SHOULD REMAIN BELOW ADVISORY CRITERIA. TROUGH 
WHICH MOVED OVER THE AREA ON TUESDAY TO CONTINUE SHIFTING EAST OUT 
OF THE AREA TODAY WITH WEAK SHORT WAVE RIDGE MOVING OVER NEVADA 
THURSDAY AND FRIDAY. NEXT TROUGH THEN PUSHES INTO THE PACNW BY 00Z 
SATURDAY LEADING TO SOUTHWEST FLOW ALOFT FRIDAY NIGHT INTO EARLY 
SATURDAY MORNING. WITH NORTHERLY FLOW OVER THE AREA TODAY CONTINUED 
COLD AIR ADVECTION TO DROP HIGHS TODAY ANOTHER 5-10 DEGREES FROM 
THOSE ON TUESDAY AND THEN WARMING TO TAKE PLACE THURSDAY WITH TEMPS 
REBOUNDING ABOVE NORMAL ON FRIDAY. OVERALL SCENARIO KEEPS THE CWA 
UNDER DRY CONDITIONS.   

.LONG TERM...INITIALLY THE GFS AND ECMWF ARE IN GOOD AGREEMENT EARLY 
IN THE WEEKEND WITH BOTH MODELS SHOWING A COLD LOW DROPPING SOUTH 
ALONG THE PAC NW COAST AND EVENTUALLY BECOMING STATIONARY ALONG THE 
OREGON COAST. THIS LOW IS FORECAST TO REMAIN ANCHORED THROUGH MONDAY 
WITH WEAK DISTURBANCES ROTATING THOUGH THE PAC NW. THIS IS EXPECTED 
TO BRING ANOTHER ROUND OF BREEZY TO WINDY CONDITIONS TO OUR AREA 
ALONG WITH A FEW DAYS OF BELOW NORMAL TEMPERATURES. WITH THIS LOW 
REMAINING SITUATED FOR A FEW DAYS...WE CAN EXPECT TO SEE A PROLONGED 
PERIOD OF BREEZY TO WINDY CONDITIONS BEGINNING FRIDAY AFTERNOON AND 
CONTINUING INTO MONDAY. TEMPERATURES ARE EXPECTED TO REMAIN ABOVE 
NORMAL THROUGH MUCH OF THE WEEKEND...BUT DROP TO BELOW NORMAL BY 
EARLY NEXT WEEK WITH SEVERAL DAYS OF BELOW NORMAL READINGS. ONCE 
AGAIN...NOT MUCH MOISTURE ASSOCIATED WITH THIS SYSTEM...BUT THE FAR 
NORTHERN AREAS MAY SEE A SLIGHT CHANCE BY THE MIDDLE OF NEXT WEEK AS 
THE LOW FINALLY BEGINS TO SHIFT EAST. 
&&

.FIRE WEATHER...NORTH WINDS WILL BE SEEN ACROSS THE DISTRICT TODAY 
BEHIND THE COLD FRONT WHICH HAS EXITED THE AREA OVERNIGHT. VERY DRY 
AIR REMAINS OVER THE AREA WITH RELATIVE HUMIDITY VALUES HAVING POOR 
RECOVERIES OVERNIGHT WHICH WILL LEAD TO MAINLY SINGLE DIGIT VALUES 
FOR THIS AFTERNOON. MAIN CONCERN WILL BE THE COLORADO RIVER BASIN 
BUT SOUTHEAST SAN BERNARDINO COUNTY AND THE SOUTHERN PORTION OF 
MOHAVE COUNTY WILL NEED TO BE MONITORED DURING THE DAY. WILL ISSUE A 
RED FLAG WARNING FOR THE COLORADO RIVER BASIN AS NORTH WINDS...GUSTS 
TO 40 MPH WILL DEVELOP DURING THE MORNING AND CONTINUE THROUGH THE 
AFTERNOON. GUSTY WINDS LIKELY OVER THE AREAS SURROUNDING THE RIVER 
BASIN DURING THE AFTERNOON AND ALTHOUGH FUELS/RELATIVE HUMIDITY 
VALUES WILL MEET CRITERIA...WINDS SHOULD BE JUST BELOW CRITERIA AND 
WILL HOLD OFF ON ANY STATEMENTS.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...WIND ADVISORY 10 AM PDT UNTIL 5 PM PDT TODAY FOR NVZ021.
     RED FLAG WARNING 10 AM PDT UNTIL 5 PM PDT TODAY FOR NVZ466.
AZ...WIND ADVISORY 10 AM MST UNTIL 5 PM MST TODAY FOR AZZ002
     AND AZZ036.
     RED FLAG WARNING 10 AM MST UNTIL 5 PM MST TODAY FOR AZZ101.
CA...WIND ADVISORY 10 AM PDT UNTIL 5 PM PDT TODAY FOR CAZ527.
     RED FLAG WARNING 10 AM PDT UNTIL 5 PM PDT TODAY FOR CAZ229.
$$

KENNEDY/JACQUES/JENSEN/GORELOW

HTTP://WEATHER.GOV/LASVEGAS