613  
FXUS65 KVEF 232044  
AFDVEF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LAS VEGAS NV  
144 PM PDT SUN SEP 23 2018  
   
SYNOPSIS
 
AFTERNOON BREEZES WILL TAPER OFF THIS EVENING.  
OTHERWISE, DRY CONDITIONS WILL PREVAIL THROUGH THE MIDDLE OF THE  
UPCOMING WEEK, AND TEMPERATURES WILL REMAIN SEVERAL DEGREES ABOVE  
NORMAL.  

 
   
SHORT TERM
 
THIS EVENING THROUGH TUESDAY.  
 
CURRENT OBSERVATIONS INDICATE THE ADVERTISED BREEZY SOUTHERLY WINDS  
HAVE DEVELOPED THIS AFTERNOON IN RESPONSE TO AN UPPER TROUGH  
SWINGING ACROSS THE NORTHWESTERN STATES. WINDS WILL TAPER OFF  
QUICKLY THIS EVENING AND LIGHTER WINDS ARE EXPECTED THROUGH AT LEAST  
MID WEEK. AS MENTIONED IN THE MORNING UPDATE, CLOUD COVER WAS  
INCREASED TO MOSTLY CLOUDY TO PARTLY CLOUDY THROUGH THE EARLY  
EVENING TO ACCOUNT FOR SHALLOW CUMULUS DEVELOPMENT. BY MONDAY LOW  
CLOUDS SHOULD BE LIMITED TO MOHAVE COUNTY AND MAINLY OVER THE  
MOUNTAINS. ELSEWHERE, ASIDE FROM A FEW PASSING HIGH CLOUDS, MOSTLY  
CLEAR SKIES ARE EXPECTED AS DRY NORTHWEST FLOW INCREASES OVER THE  
AREA TONIGHT. CURRENT SUITE OF GUIDANCE SHOWS A REX BLOCK PATTERN  
DEVELOPING ON TUESDAY, WHICH WOULD CONTINUE A WEAK DRY NORTHWEST  
FLOW ACROSS THE AREA. UNDER THIS PATTERN, TEMPERATURES WILL REMAIN 5-  
8 DEGREES ABOVE NORMAL.  
   
LONG TERM
 
WEDNESDAY THROUGH SUNDAY.  
 
THE PERIOD STARTS OUT WITH A NARROW, HIGHLY AMPLIFIED RIDGE OVER THE  
WESTERN GREAT BASIN, CALIFORNIA EXTENDING NORTHWARD INTO THE GULF OF  
ALASKA. THIS RIDGE IS SANDWICHED BETWEEN A CLOSED LOW OVER THE  
EASTERN PACIFIC AND LONGWAVE TROUGH OVER THE CENTRAL U.S. MODELS  
AGREE CLOSED LOW OVER THE EASTERN PACIFIC WILL UNDERCUT THE RIDGE  
AND SLOWLY DRIFT TOWARD THE NORTHERN CALIFORNIA COAST THURSDAY AND  
FRIDAY. MODEL DIFFERENCES BECOME GREATEST OVER THE WEEKEND REGARDING  
TROUGH DEPTH AND FORWARD SPEED AS IT MOVES INLAND THROUGH NORTHERN  
CALIFORNIA AND THE NORTHERN GREAT BASIN NEXT WEEKEND. BOTTOM LINE,  
THE REGION WILL REMAIN UNSEASONABLY WARM AND DRY WEDNESDAY-FRIDAY  
WITH ONLY A SLIGHT DROPOFF IN TEMPS NEXT WEEKEND. BREEZES WILL  
LIKELY INCREASE NEXT WEEKEND AS WELL. HOW STRONG THE WINDS GET WILL  
DEPEND ON JUST HOW DEEP THE TROUGH WILL BE AS IT MOVES INLAND.  

 
   
AVIATION...FOR MCCARRAN.
 
SOUTHWEST WINDS WITH GUSTS UP TO 25  
KNOTS WILL CONTINUE THROUGH THE EARLY EVENING BEFORE GUSTS QUICKLY  
SUBSIDING AROUND 02Z. OVERNIGHT SOUTHWEST DRAINAGE BECOMING LIGHT  
VARIABLE BY SUNRISE MONDAY. BY MID-MORNING, A LIGHT EAST WIND SHOULD  
DEVELOP THEN SHIFT TO THE SOUTHEAST AROUND 19Z. WINDS WILL SHIFT TO  
SOUTHWEST BETWEEN 22Z-00Z WITH SPEEDS 10-15 KNOTS AND GUSTS UP TO 20  
KNOTS POSSIBLE. NO OPERATIONALLY SIGNIFICANT CLOUD COVER EXPECTED.  
 
FOR THE REST OF SOUTHERN NEVADA, NORTHWEST ARIZONA AND SOUTHEAST  
CALIFORNIA....SOUTHERLY WINDS WILL CONTINUE AT MOST SITES THROUGH  
THE EVENING. OVERNIGHT WINDS ARE EXPECTED DECREASE AND FOLLOW CLOSE  
TO DIURNAL TRENDS. SIMILAR WIND TRENDS ARE EXPECTED MONDAY WITH  
SPEEDS BETWEEN 5-15 KNOTS. VFR CONDITIONS EXPECTED THROUGH THE  
PERIOD.  

 
   
SPOTTER INFORMATION STATEMENT
 
SPOTTERS ARE ENCOURAGED TO REPORT  
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING  
PROCEDURES.  

 
 

 
 
SHORT TERM/AVIATION...BOOTHE  
LONG TERM.............PIERCE  
 
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:  
 
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER  
 
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