526
FXUS65 KVEF 200507
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
ISSUED BY NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1006 PM PDT MON MAY 19 2025
SYNOPSIS
THIS WEEK WILL SEE A SIGNIFICANT WARMING TREND THAT
WILL RESULT IN WHAT IS LIKELY TO BE THE FIRST 100 DEGREE DAY OF
THE YEAR IN LAS VEGAS ON THURSDAY. THURSDAY WILL BE THE HOTTEST
DAY OF THE WEEK, BEFORE A SLOW, GRADUAL COOLING TREND HEADING INTO
NEXT WEEKEND. A WEAK DISTURBANCE IS EXPECTED TO BRING INCREASED
WINDS TO THE REGION OVER THE WEEKEND, BUT CURRENTLY, THE FORECAST
REMAINS DRY.
UPDATE
NORTHERLY BREEZES CONTINUE TO WANE THIS EVENING AS THE
SUN SETS. LIGHT WINDS EXPECTED THE NEXT COUPLE OF DAYS AS
TEMPERATURES WARM TO ABOVE-NORMAL VALUES. BREEZES UPTICK ON THURSDAY
WHILE HIGHS PEAK ACROSS THE AREA, WITH LAS VEGAS POTENTIALLY SEEING
ITS FIRST 100 OF THE SEASON. GUSTY WINDS AND SLIGHTLY COOLER
TEMPERATURES ARRIVE FRIDAY WITH OUR NEXT SYSTEM. DRY CONDITIONS
PREVAIL AS RAIN CHANCES REMAIN BELOW 10%.
SHORT TERM
THROUGH TUESDAY.
SUNNY SKIES AND NORTHERLY BREEZES ARE THE RULE FOR MOST OF THE
REGION TODAY AS THE TROUGH RESPONSIBLE FOR THE UNSETTLED WEATHER
OVER THE WEEKEND TRANSLATES EASTWARD ACROSS THE ROCKIES, LEAVING
SOUTHEASTERN CALIFORNIA, SOUTHERN NEVADA, AND NORTHWESTERN ARIZONA
BENEATH NORTHWEST FLOW ALOFT. MID-LEVEL MOISTURE IS TEMPERING OUR
WARM-UP SOMEWHAT THIS AFTERNOON, THOUGH IT IS STILL UNDERWAY,
WITH TEMPERATURES ON TARGET TO TOP OUT AT LEAST A FEW DEGREES
WARMER THAN YESTERDAY, BUT STILL SLIGHTLY BELOW NORMAL FOR THE
MIDDLE OF MAY. WINDS WILL DIE DOWN LATE THIS AFTERNOON THROUGH
THIS EVENING WITH THE LOSS OF MIXING AND AS THE SURFACE PRESSURE
GRADIENT SLACKENS, WITH LOWS RANGING FROM THE 40S IN THE MOUNTAINS
TO 60S AND 70S IN THE VALLEYS. HEADING INTO TUESDAY, THE WARMING
TREND WILL CONTINUE AS RIDGING DEVELOPS OVER THE SOUTHEASTERN
PACIFIC, AND FLOW ALOFT TRANSITIONS TO QUASI-ZONAL. INCREASING
THICKNESSES WILL LEND TO HIGHS REBOUNDING ABOVE NORMAL INTO THE
80S AND 90S FOR MOST, WITH TRIPLE DIGITS IN DEATH VALLEY AND 70S
CONFINED TO THE HIGHER TERRAIN. AS TO BE EXPECTED IN THIS REGIME,
CLEAR SKIES AND DRY CONDITIONS WILL CONTINUE.
LONG TERM
WEDNESDAY THROUGH SUNDAY.
THE RIDGE WILL CONTINUE TO BUILD OVER THE SOUTHWEST US THE SECOND
HALF OF THE WEEK. TEMPERATURES THROUGH THE WEEK WILL WARM EACH DAY
IN RESPONSE TO BUILDING HEIGHTS. THE RIDGE IS KNOCKED DOWN SLIGHTLY
ON THURSDAY AS A WEAK SHORTWAVE MOVES THROUGH THE PACIFIC NORTHWEST,
BUT ANOMALOUSLY HIGH HEIGHTS WILL REMAIN OVER THE AREA. THIS
COMBINED WITH A SLIGHT INCREASE IN WINDS TO ADD IN MIXING MEANS
THURSDAY WILL LIKELY BE THE WARMEST DAY OF THE WEEK. THE PROBABILITY
OF REACHING 100 DEGREES IN LAS VEGAS ON THURSDAY IS 75 PERCENT,
AND THERE IS A 25 PERCENT CHANCE FOR DEATH VALLEY TO REACH 110
DEGREES. WEDNESDAY AND THURSDAY, EXPECT WIDESPREAD MODERATE (LEVEL
2) HEATRISK ACROSS THE DESERT VALLEYS, A LEVEL OF HEAT THAT
AFFECTS ANYONE SENSITIVE TO HEAT, ESPECIALLY THOSE WITHOUT
ADEQUATE COOLING OR HYDRATION. THERE IS ALSO THE POTENTIAL FOR
SOME MAJOR (LEVEL 3) HEATRISK ALONG THE COLORADO RIVER AS WELL AS
DEATH VALLEY, WHICH AFFECTS ANYONE WITHOUT EFFECTIVE COOLING OR
HYDRATION. KNOW WHERE TO FIND THE NEAREST COOL LOCATION AND BRING
PLENTY OF WATER IF PLANNING ON SPENDING TIME OUTDOORS.
FORECAST UNCERTAINTY INCREASES FRIDAY INTO THE WEEKEND AS MODELS TRY
TO RESOLVE HOW THE RIDGE BUILD BACK INTO THE RIDGE AND HOW IT
INTERACTS WITH ANOTHER MORE POTENT PACIFIC NORTHWEST SHORTWAVE.
FRIDAY SHOULD CONTINUE TO BE WARM AS MOST MODELS SHOW SOME FLAVOR
OF A RIDGE REMAINING OVER THE AREA. HIGH TEMPERATURES ON FRIDAY
SHOULD ONLY COOL A FEW DEGREES, THUS SIMILAR HEATRISK IMPACTS ARE
EXPECTED ON THURSDAY AS MENTIONED ABOVE. AFTER THAT, THERE IS TOO
MUCH MODEL VARIANCE TO DETERMINE POTENTIAL IMPACTS AND SPECIFICS.
WILL CONTINUE TO MONITOR FOR WIND AND OTHER POTENTIAL IMPACTS AS
CONFIDENCE IS TOO LOW TO DETERMINE DETAILS GIVEN THE HIGH
UNCERTAINTY.
AVIATION...FOR HARRY REID...FOR THE 06Z FORECAST PACKAGE
LIGHT
AND DIURNAL OR VARIABLE WINDS THROUGH THE NIGHT AND TUESDAY MORNING.
DURING THE AFTERNOON HOURS TOMORROW, WINDS WILL BEGIN TO TURN
SOUTHEASTERLY AND EVENTUALLY SOUTH-SOUTHWESTERLY. DURING THE
TRANSITION, THESE IS A 30% CHANCE OF SPEEDS REACHING 10+ KNOTS.
BETTER CHANCES (50%) OF 10+ KNOTS COME WITH THE SOUTH-SOUTHWEST
WINDS IN THE LATE AFTERNOON AND EARLY EVENING. THE EARLIER THE
SOUTHWEST WINDS ARRIVE, THE BETTER ODDS OF SEEING 10+ KNOTS. VFR
CONDITIONS AND CLEAR SKIES.
FOR THE REST OF SOUTHERN NEVADA, NORTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...FOR THE 06Z FORECAST PACKAGE...PREDOMINANTLY LIGHT AND
DIURNAL WIND PATTERNS EXPECTED ACROSS THE AREA TONIGHT AND TOMORROW.
MOST SITES WILL SEE THEIR WINDS REMAIN BELOW 10 KNOTS. BEST CHANCE
FOR 10+ KNOTS IS AT DAG (90%) WHILE SITES IN THE LAS VEGAS VALLEY
HAVE 40-60% ODDS (MAINLY HND AND LAS AS SOUTHWEST WINDS PUSH
TOMORROW AFTERNOON). VFR CONDITIONS AND CLEAR SKIES.
SPOTTER INFORMATION STATEMENT
SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING
PROCEDURES.
UPDATE...WOODS
SHORT TERM...PHILLIPSON
LONG TERM...NICKERSON
AVIATION...WOODS
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