240  
FXUS65 KVEF 270422 CCA  
AFDVEF  
 
AREA FORECAST DISCUSSION...CORRECTED  
NATIONAL WEATHER SERVICE LAS VEGAS NV  
920 PM PDT WED APR 26 2017  
   
SYNOPSIS
 
A NORTHWEST FLOW WILL GIVE WAY TO A STRONGER DISTURBANCE  
CLIPPING THE REGION FROM THE NORTH ON FRIDAY. THIS WILL RESULT IN A  
PERIOD OF NORTH OR NORTHWEST WINDS FOR MUCH OF THE REGION, AND  
POTENTIALLY STRONG WINDS DOWN THE COLORADO RIVER VALLEY. CONDITIONS  
THROUGH EARLY NEXT WEEK WILL REMAIN GENERALLY DRY WITH A COOL DOWN  
FRIDAY AND SATURDAY. A WARMING TREND WILL COMMENCE SUNDAY AS THE  
DISTURBANCE PUSHES EAST.  

 
   
UPDATE
 
THE LATEST SURFACE OBSERVATIONS AND RADAR VELOCITY DATA  
SHOWED A CONSIDERABLE INCREASE IN SOUTHWEST TO WEST WINDS AROUND  
SOUTHERN NEVADA IN THE PAST HOUR OR SO WITH GUSTS OF 25-30 MPH. THIS  
IS IN RESPONSE TO THE APPROACHING COLD FRONT AND THE ASSOCIATED  
SURFACE PRESSURE GRADIENT INCREASE. THE FRONT WAS JUST NORTHWEST OF  
INDIAN SPRINGS AT 04Z, AND WILL PUSH ACROSS CENTRAL CLARK COUNTY  
AROUND MIDNIGHT. THIS WILL USHER IN A PROLONGED PERIOD OF GUSTY  
NORTH WINDS AS A DEEP UPPER LOW SLIDES OVER NEVADA, UTAH AND ARIZONA  
FRIDAY INTO SATURDAY. MINOR ADJUSTMENTS WERE MADE TO THE WIND GRIDS  
TONIGHT. THE REST OF THE FORECAST TRENDS LOOK GOOD. -ADAIR  

 
 
   
SHORT TERM
 
THROUGH FRIDAY NIGHT.  
 
BIGGEST CONCERNS THROUGH THE SHORT TERM CONTINUE TO BE THE WINDS, AS  
WELL AS THE POTENTIAL FOR DAMAGING WINDS ALONG THE COLORADO RIVER  
THURSDAY NIGHT INTO SATURDAY. NORTHWEST FLOW ALOFT DOMINATES THE  
WEATHER PATTERN CURRENTLY WITH A WEAK FRONTAL PASSAGE PROGGED TO  
SLIDE SOUTH ACROSS THE REGION THIS EVENING. THIS WILL RESULT IN SOME  
STRONG WINDS MAINLY ACROSS THE WESTERN MOJAVE DESERT AND PARTS OF  
THE SOUTHERN GREAT BASIN WHERE GUSTS OVER 40 MPH WILL BE POSSIBLE.  
ELSEWHERE, A SWITCH TO NORTH OR NORTHWEST WINDS WILL BE NOTICED  
TONIGHT WITH A BRIEF PERIOD OF GUSTINESS POSSIBLE OVERNIGHT ALONG  
THE COLORADO RIVER AS THE FRONT MOVES THROUGH.  
 
TOMORROW...NORTH WINDS WILL LINGER BUT THE STRENGTH OF THE WINDS  
WILL DECREASE THROUGH THE MORNING HOURS FOR MOST LOCATIONS.  
MEANWHILE...A REINFORCING SHOT OF NORTH WINDS ARRIVES THURSDAY  
EVENING IN ASSOCIATION WITH A TROUGH BEGINNING TO SLIDE ACROSS THE  
GREAT BASIN AND INTO THE FOUR CORNERS.  
 
THIS IS TRADITIONALLY A WINDY SET UP FOR THE COLORADO RIVER VALLEY,  
AND THIS EVENT TAKES NO EXCEPTION. MOS GUIDANCE SUGGESTS SUSTAINED  
WINDS EXCEEDING 40 MPH AT TIMES NEAR LAUGHLIN/BULLHEAD CITY, AND  
PERHAPS GETTING CLOSE ALONG OTHER RIVER LOCATIONS AS WELL (NEEDLES,  
HAVASU, ETC). WHILE HIGH RESOLUTION GUIDANCE IS NOT YET AS BULLISH,  
PATTERN RECOGNITION AND MOS GUIDANCE, AS WELL AS FAIRLY SUBSTANTIAL  
PRESSURE GRADIENT HAVE LED ME TO ISSUE A HIGH WIND WATCH FOR THIS  
AREA. THE NEXT COUPLE SHIFTS CAN CONTINUE TO EVALUATE THE POTENTIAL.  
REGARDLESS OF THE EXACT WIND SPEEDS WHICH UNFOLD, IT WILL BE VERY  
WINDY FROM COTTONWOOD COVE SOUTHWARD FRIDAY AND SATURDAY, AND THOSE  
PLANNING EVENTS OR OUTDOOR RECREATION SHOULD BE WELL PREPARED FOR  
THE EXPECTED WIND IMPACTS.  
 
TEMPERATURES THURSDAY WILL BE FAIRLY SIMILAR TO THOSE OBSERVED  
TODAY, WITH A COOL DOWN COMMENCING FRIDAY AS HEIGHTS FALL IN  
RESPONSE TO THE DEVELOPING TROUGH.  
   
LONG TERM
 
SATURDAY THROUGH TUESDAY. NORTH WINDS WILL CONTINUE ON  
SATURDAY AS NOTED IN THE SHORT TERM DISCUSSION, THEN SUBSIDE  
SATURDAY NIGHT AS THE LOW MOVES AWAY TO THE EAST. THE NEXT FEATURE  
OF INTEREST IS HIGH PRESSURE BUILDING OFF THE WEST COAST, AND  
WHETHER/WHEN IT WILL MOVE INLAND. THE OPERATIONAL GFS AND ECMWF HAVE  
BOTH BACKED AWAY FROM PREVIOUS RUNS WHICH SHOWED ANOTHER TROUGH  
DIVING DOWN THE FRONT SIDE OF THE RIDGE AND AMPLIFYING INTO THE  
DESERT SOUTHWEST, AND NOW SHOW THE RIDGE WORKING ITS WAY INLAND WITH  
RISING HEIGHTS AND WARMING TEMPERATURES. HOWEVER, ONLY ABOUT HALF OF  
THE ENSEMBLE MEMBERS AGREE WITH THIS IDEA, WITH SOME HOLDING ON TO  
THE TROUGH. WITH THE UNCERTAINTY IN MIND, NUDGED TEMPERATURES  
HALFWAY TOWARD THE NEW MODEL GUIDANCE. THIS PUTS KLAS INTO THE UPPER  
80S EARLY NEXT WEEK, WHERE NEW MODEL GUIDANCE SUGGESTS 90 OR HIGHER.  
IF FUTURE MODEL RUNS CONTINUE TO TREND TOWARD THE RIDGING SOLUTION,  
TEMPERATURES WILL NEED TO BE BUMPED UP ACCORDINGLY. STAY TUNED.  

 
   
AVIATION...FOR MCCARRAN
 
A FRONTAL PASSAGE WILL ARRIVE AROUND  
06Z-07Z WITH THE WINDS SHIFTING TO THE NORTHWEST WITH OCCASIONAL  
GUSTS OF 20-25 KNOTS. BREEZY NORTH WINDS WILL PERSIST MOST OF THE  
DAY THURSDAY WITH GUSTS TO 25 KNOTS POSSIBLE AND OCCASIONAL  
VARIANCES BETWEEN NORTHWEST AND NORTHEAST DIRECTIONS.  
 
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST  
CALIFORNIA...BREEZY CONDITIONS WILL EXIST ACROSS MOST OF THE REGION  
THROUGH THE PERIOD. WEST WINDS WITH GUSTS OVER 35 KNOTS CAN BE  
EXPECTED NEAR KDAG AND KNXP THIS AFTERNOON THROUGH EARLY THURSDAY  
MORNING WITH SOME IMPROVEMENT MIDMORNING BEFORE THE WEST WINDS  
RETURN THURSDAY EVENING. SOUTH WINDS OF 10-15 KNOTS WILL GIVE WAY TO  
NORTH WINDS TONIGHT DOWN THE COLORADO RIVER WITH GUSTS OF 20-25  
KNOTS EXPECTED NEAR KIFP AND KEED. MUCH STRONGER NORTH WINDS  
POSSIBLE FRIDAY AND SATURDAY. MEANWHILE...PERIODS OF NORTHWEST WINDS  
EXPECTED NEAR KBIH WITH GUSTS TO 20 KNOTS POSSIBLE. SKIES SHOULD  
GENERALLY CONSIST OF ONLY SCATTERED HIGH CLOUDS.  

 
   
FIRE WEATHER
 
DRY AND BREEZY CONDITIONS EXPECTED THE NEXT SEVERAL  
DAYS WITH WINDY CONDITIONS EXPECTED ALONG THE COLORADO RIVER. STRONG  
WINDS COMBINED WITH LOW RELATIVE HUMIDITIES WILL RESULT IN A PERIOD  
OF CRITICAL FIRE WEATHER FRIDAY AND SATURDAY ALONG THE COLORADO  
RIVER VALLEY AND A FIRE WEATHER WATCH HAS BEEN POSTED FOR THIS  
POTENTIAL. IMPROVING CONDITIONS ARE EXPECTED SUNDAY AS WIND SPEEDS  
DECREASE BUT CONDITIONS WILL REMAIN DRY.
 
   
SPOTTER INFORMATION STATEMENT
 
SPOTTERS ARE ENCOURAGED TO REPORT  
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING  
PROCEDURES.  

 
 

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