752
FXUS65 KVEF 271829
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1129 AM PDT THU MAR 27 2025
SYNOPSIS
A MORE ACTIVE PATTERN RETURNS BEGINNING TODAY, WITH
INCREASED WINDS AND TEMPERATURES TRENDING TOWARD MORE SEASONAL
READINGS. OTHER THAN SOME LOW PRECIPITATION CHANCES IN THE SIERRA
AND SOUTHERN GREAT BASIN THIS WEEKEND AND EARLY NEXT WEEK, DRY
CONDITIONS WILL PREVAIL.
UPDATE
A WIDESPREAD AREA OF UPPER LEVEL DIFFLUENCE WAS NOTED ON
RAP 500MB MESOANALYSIS AS WELL AS SATELLITE AS A PLUME OF CLOUDS
DRAPED FROM IDAHO TO SOUTHEAST CALIFORNIA. THIS DIFFLUENCE ALOFT
OVER THE REGION SET UP HEAD OF AN UPPER LEVEL LOW SPINNING OFF THE
PACIFIC NORTHWEST COAST, SLOWLY MARCHING EASTWARD THROUGH THE
MORNING. ABUNDANT CLOUD COVER WAS NOTED THIS HOUR THROUGH CLARK,
LINCOLN, AND MOHAVE COUNTIES AS WELL AS IN THE COLORADO RIVER
VALLEY. BEHIND THIS FEATURE, SKIES WERE MOSTLY CLEAR. WITH THE
TIGHTENING PRESSURE GRADIENT, INCREASING SOUTH TO SOUTHWEST WINDS
WERE REPORTED THIS MORNING WITH GUSTS 20-25 MPH REPORTED IN MANY
LOCATIONS. AS HEIGHTS WERE FALLING, TEMPERATURES THIS MORNING WERE
SLIGHTLY COOLER THAN YESTERDAY AT THIS TIME.
OVERALL, DID NOT MAKE ANY SIGNIFICANT CHANGES TO THE AFTERNOON
FORECAST. WILL BE ON METWATCH THROUGH THE AFTERNOON TO SEE IF
DOWNSLOPE WINDS DEVELOP IN THE SIERRA AND OWENS VALLEY. FORECAST
SOUNDINGS ON SOME HI-RES MODELS SHOW DOWNSLOPE FAVORABLE SET UPS
THIS AFTERNOON WITH NEGATIVE VERTICAL SHEAR AND AN INVERSION NEAR
RIDGETOP LEVEL. HOWEVER OTHER HI-RES MODEL SOUNDINGS LACK THIS
INVERSION AND SHOW WEAKER NEGATIVE SHEAR. COMPARED TO PREVIOUS
DOWNSLOPE EVENTS IN THE SIERRA, THIS SYNOPTIC SETUP IS SIMILAR TO
OTHER DOWNSLOPE SET UPS. WHILE NBM PROBABILITIES ARE STILL NOT
EXCITED FOR STRONG WINDS IN THE OWENS VALLEY, SHOWING LESS THAN 10%
PROBABILITY FOR PEAK WIND GUSTS OVER 60 MPH...THE SETUP IS TOO
CLASSIC TO IGNORE. HREF PROBABILITIES PAINT A BETTER PICTURE OF WHAT
COULD HAPPEN WITH 30%-50% PROBABILITIES FOR WIND GUSTS OVER 60 MPH
AFTER 2 PM PT BETWEEN BIG PINE AND OLANCHA. BOTH ENSEMBLE
PROBABILITIES HAVE HIGH CHANCES (70%+) FOR WIND GUSTS OVER 40 MPH,
WHICH WILL BE IMPACTFUL EVEN IF THE STRONGER DOWNSLOPE WINDS DO NOT
DEVELOP DUE TO STRONG CROSSWINDS. ANYONE DRIVING ON HIGHWAY 395 THIS
AFTERNOON AND EARLY EVENING SHOULD BE PREPARED FOR STRONG CROSSWINDS
THAT WILL MAKE DRIVING CONDITIONS DANGEROUS. THE DOWNSLOPE POTENTIAL
WILL DECREASE AFTER 8PM TONIGHT WITH WINDS DIMINISHING QUICKLY
TONIGHT. THE HIGH WIND WARNING IS NOW IN EFFECT FOR THE EASTERN
SIERRA SLOPES AND THE OWENS VALLEY.
ELSEWHERE, SOUTH TO SOUTHWEST WINDS WILL CONTINUE TO INCREASE ACROSS
THE REGION. THE GREATEST POTENTIAL FOR WIND IMPACTS WILL BE THROUGH
THE WESTERN MOJAVE DESERT AS WELL AS IN THE SPRING MOUNTAINS. THIS
IS WHERE THE BEST CHANCES FOR WIND GUSTS OVER 40 MPH IN THE VALLEYS
AND OVER 50 MPH IN MOUNTAINS, WITH THE HIGHEST WINDS DEVELOPING
AFTER 4 PM PT THIS AFTERNOON AS THE 850MB REALLY RAMPS UP AND SITS
OVER THE AREA THROUGH THE NIGHT. GUSTY WINDS ARE ALSO POSSIBLE
THROUGH EASTERN SAN BERNARDINO INTO FAR SOUTHERN CLARK COUNTY.
PROBABILITIES FOR IMPACTFUL WINDS OVER 40 MPH ARE LOWER FOR THESE
AREAS, ONLY ABOUT A 40% CHANCE, BUT WITH THE PEAK OF THE WINDS BEING
DURING THE THE EVENING COMMUTE, THERE ARE POTENTIAL IMPACTS TO
COMMUTERS ON I-15 AND I-40 IN THESE AREAS. A WIND ADVISORY IS
IN EFFECT FOR MUCH OF SAN BERNARDINO COUNTY FROM BARSTOW, CA AND
BAKER, CA INTO EASTERN SAN BERNARDINO AND SOUTHERN CLARK COUNTIES AS
WELL AS IN THE SPRING MOUNTAINS THROUGH THE NIGHT.
OTHER THAN THE WINDS, WEATHER IMPACTS ARE NOT EXPECTED TODAY. THE
LOW LEVELS ARE DRY SO ANY UPPER LEVEL MOISTURE WILL REMAIN JUST
CLOUDS. TEMPERATURES TODAY WILL BE COOLER THAN YESTERDAY, BUT WILL
STILL BE RUNNING ABOVE NORMAL AS HIGH TEMPERATURES TODAY WILL ONLY
DROP ABOUT 3-5 DEGREES COMPARED TO YESTERDAY.
-NICKERSON-
PREVIOUS DISCUSSION
418 AM PDT THU MAR 27 2025
SHORT TERM
TODAY THROUGH FRIDAY.
THE RIDGE THAT BROUGHT THE WELL ABOVE NORMAL TEMPERATURES ALONG WITH
A FEW RECORD HIGHS OVER THE PAST COUPLE OF DAYS HAS SHIFTED EAST
AHEAD OF AN INCOMING PACIFIC TROUGH. FOR STARTERS, WE WILL SEE SOME
SLIGHTLY COOLER TEMPERATURES TODAY WITH READINGS ABOUT 3-5 DEGREES
LOWER THAN WEDNESDAY. THE MAIN IMPACT FROM THIS TROUGH WILL BE
INCREASING WINDS ACROSS MUCH OF THE REGION. THE STRONGEST WINDS LOOK
TO BE IN THE EASTERN SIERRA AND OWENS VALLEY AS THE SURFACE PRESSURE
GRADIENT INCREASES AND THE UPPER LEVEL WINDS BECOME WESTERLY. THE
LATEST CROSS SECTIONS SHOW THE POTENTIAL FOR A STRONG DOWNSLOPE
EVENT WITH THE POTENTIAL OF WINDS GUSTS REACHING 50-70 MPH OVER THE
EASTERN SIERRA SLOPES AND POTENTIALLY REACHING 50-60 MPH OVER THE
FAR WESTERN AREAS OF THE OWENS VALLEY, ESPECIALLY SOUTH OF BIG PINE.
THESE NUMBERS ARE SUPPORTED BY THE LATEST HREF WHERE EVEN THE
ENSEMBLE MINIMUMS ARE INDICATING THE POTENTIAL OF WIND GUSTS OVER 60
MPH. THE NBM ISN'T QUITE AS BULLISH, BUT STILL SHOWING MEAN WIND
GUSTS BETWEEN 40-50 MPH. DUE TO THE POTENTIAL OF SEEING THESE
STRONGER WIND GUSTS, HAVE ELECTED TO UPGRADE THE WIND ADVISORY TO A
HIGH WIND WARNING FOR THE EASTERN SIERRA SLOPES AND THE OWENS VALLEY
WHICH WILL RUN FROM 11AM THIS MORNING UNTIL 11PM THIS EVENING.
THE OTHER AREA OF CONCERN WILL BE ACROSS THE MOJAVE DESERT INTO
SOUTHERN CLARK COUNTY WHERE THE LATEST MODEL RUNS INDICATE THE
POTENTIAL FOR WIND GUSTS OVER 40 MPH. WENT AHEAD AND ISSUED A WIND
ADVISORY FOR THE NORTHERN HALF OF SAN BERNARDINO COUNTY ALONG WITH
THE SPRING MOUNTAINS AND SOUTHERN CLARK COUNTY FROM 11AM UNTIL 4AM
FRIDAY. BOTH THE HREF AND NBM INDICATE GUSTY WINDS BEGINNING LATE
MORNING, BUT THE STRONGEST WINDS ARE LIKELY NOT EXPECTED TO OCCUR
UNTIL MID TO LATE AFTERNOON AND CONTINUE INTO THE EVENING WITH GUSTS
TO AROUND 45 MPH. THE SPRING MOUNTAINS WILL SEE GUSTS TO AROUND 50
MPH THIS AFTERNOON, BUT THE HIRES MODELS ARE INDICATING THE
POTENTIAL FOR A BRIEF PERIOD OF STRONG DOWNSLOPE WINDS LATE THIS
EVENING WHERE GUSTS UP TO 55 MPH ARE POSSIBLE. THERE IS SOME
POTENTIAL OF THESE HIGHER WINDS TO REACH THE FAR WESTERN EDGES OF
THE LAS VEGAS VALLEY, BUT OVERALL IT IS NOT EXPECTED TO BE
WIDESPREAD. DUE TO THE SLOW NATURE OF THE TROUGH, SURFACE GRADIENTS
LOOK TO REMAIN IN PLACE ACROSS THE WESTERN MOJAVE DESERT, SO THE
WIND ADVISORIES MAY NEED TO BE EXTENDED THROUGH FRIDAY.
TEMPERATURES WILL DROP A FEW DEGREES TODAY AND THEN DROP CLOSER TO
NORMAL BY FRIDAY.
LONG TERM
SATURDAY THROUGH TUESDAY.
A WEAK SHORTWAVE WILL PUSH THROUGH THE GREAT BASIN ON SATURDAY,
KEEPING HEIGHTS SUPPRESSED AND BRUSHING FAR NORTHERN LINCOLN COUNTY
WITH SOME LIGHT PRECIPITATION CHANCES. THIS SHORTWAVE WILL ALSO WORK
TO KEEP REGIONAL TEMPERATURES NEAR THEIR TYPICAL NORMALS FOR LATE
MARCH. THEREAFTER, A LOW AMPLITUDE SHORTWAVE RIDGE WILL ATTEMPT TO
BUILD INTO THE SOUTHWEST BUT WILL BE LIMITED IN NORTHWARD PROGRESS
BY FAIRLY DEEP TROUGHING OFF THE WEST COAST. THIS WILL POSITION OUR
REGION IN A MORE SOUTHWESTERLY FLOW ALOFT PATTERN WITH THE STORM
TRACK JUST TO OUR NORTH, THOUGH SOME LIGHT PRECIPITATION MAY EXTEND
AS FAR SOUTH AS THE SIERRA. MEANWHILE, WIDESPREAD BREEZY/WINDY
CONDITIONS WILL REMAIN A POSSIBILITY SUNDAY THROUGH EARLY NEXT WEEK,
ESPECIALLY ACROSS THE WESTERN MOJAVE DESERT WHERE THE WINDS NEVER
REALLY LET UP OVER THE WEEKEND. THERE REMAINS CONSIDERABLE
UNCERTAINTY MONDAY ONWARD IN EXTENDED RANGE MODEL GUIDANCE WITH
VARIABILITY IN THE DEPTH AND TIMING OF THE NEXT PACIFIC TROUGH TO
MOVE IN. SOME OF THE DEEPER SOLUTIONS WOULD SUGGEST FAIRLY
WIDESPREAD STRONG WINDS ON TUESDAY OR WEDNESDAY, WHILE WEAKER
SOLUTIONS WOULD KEEP CONDITIONS A BIT MORE TAME. FOR NOW,
ANTICIPATING THAT GUSTY WEATHER WILL CONTINUE HEADING INTO THE START
OF APRIL, BUT WITH LIMITED CONFIDENCE ON THE STRENGTH OF THE WINDS
AT THIS TIME.
AVIATION...FOR HARRY REID...FOR THE 18Z FORECAST PACKAGE
GUSTY
SOUTHWEST WINDS WILL CONTINUE TO INCREASE THROUGH THE AFTERNOON AND
EVENING, WITH PEAK SPEEDS BETWEEN 30 AND 35 KTS. CHANCE OF GUSTS
EXCEEDING 35 KTS AT THE TERMINAL IS 20-30 PERCENT BETWEEN 00Z AND
06Z AND 40-50 PERCENT BETWEEN 06Z AND 12Z. GUST SPEED AND FREQUENCY
DECREASE FRIDAY AFTERNOON, BUT SUSTAINED SPEEDS REMAIN ELEVATED
BETWEEN 8 AND 12 KTS, WITH GUST POTENTIAL RETURNING FRIDAY EVENING.
SCT-BKN AOA 15 KFT THROUGH THE TAF PERIOD.
FOR THE REST OF SOUTHERN NEVADA, NORTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...FOR THE 18Z FORECAST PACKAGE...GUSTY SOUTHWEST WINDS
WILL CONTINUE TO INCREASE ACROSS THE AREA THROUGH THE AFTERNOON AND
EVENING, WITH PEAK SPEEDS BETWEEN 30 AND 35 KTS AT LAS VEGAS VALLEY
TAF SITES. KDAG WILL EXPERIENCE WEST GUSTS BETWEEN 35 AND 45 KTS,
AND KEED / KIFP WILL EXPERIENCE SOUTH GUSTS BETWEEN 20 AND 30 KTS.
KBIH WILL EXPERIENCE GUSTY WESTERLY DOWNSLOPE WINDS OFF THE SIERRA
THIS AFTERNOON, BUT WILL UNDERGO A WIND SHIFT FROM THE NORTH-
NORTHWEST TONIGHT THAT WILL REDUCE GUSTS. HOWEVER, THERE IS
CONSIDERABLE TIMING UNCERTAINTY WITH THIS WIND SHIFT, WHICH MAY BE
ASSISTED BY WEAK VIRGA SHOWERS IN THE AREA THIS EVENING. FAVORING A
00-04Z TIMEFRAME FOR THE NORTH-NORTHWEST SHIFT. SCT-BKN AOA 15 KFT
THROUGH THE TAF PERIOD.
SPOTTER INFORMATION STATEMENT
SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING
PROCEDURES.
SHORT TERM...GORELOW
LONG TERM...OUTLER
AVIATION...SOULAT
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