690
FXUS65 KVEF 171056
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
356 AM PDT WED AUG 17 2022
SYNOPSIS
MONSOON SHOWS NO SIGNS OF LETTING UP AS SHOWERS AND
THUNDERSTORMS REMAIN IN THE FORECAST THROUGH THE NEXT TWO WEEKS
ACCORDING TO LONG RANGE PROJECTIONS. WHILE EBBS AND FLOWS IN
MOISTURE CONTENT WILL CONTINUE, ABOVE AVERAGE PWAT FOR THE REGION
IS EXPECTED THROUGH THE NEXT TWO WEEKS. ANOTHER TREND UPWARD IS
EXPECTED LATE WEEK AND INTO THE WEEKEND, WITH HIGHER POPS AND A
POTENTIALLY SIGNIFICANT FLASH FLOODING EVENT FOR ARIZONA.
SHORT TERM
TODAY AND TONIGHT.
TODAY'S CONVECTION CHANCES WILL BE A SLIGHTLY DIFFERENT FLAVOR
THAN THE LAST SEVERAL DAYS AS THE MAIN LIFTING MECHANISM
DYNAMICALLY IS ACTUALLY OVER THE CALIFORNIA COAST. A MEAGER TROUGH
WILL COME ON SHORE AND FOCUS DYNAMICAL LIFTING AT THE 700-500 MB
LEVEL OVER THE SIERRA NEVADA CREST. ALSO GEFS/EC PWATS SHOW 2+
SIGMA ANOMALIES OVER NORTHERN INYO AND MONO COUNTIES THIS
AFTERNOON. SHOULD BE PLENTY OF INGREDIENTS FOR CONVECTION IN THESE
AREAS AND WITH IT, FLASH FLOODING CONCERNS. FARTHER EAST, AWAY
FROM THE AFOREMENTIONED LIFTING, A MORE TRADITIONAL MONSOON SETUP
LOOKS LIKELY, WITH HIGH TERRAIN CONVECTION BEING THE FOCUS OF CI
THIS AFTERNOON AND VERY LITTLE FLOW ALOFT. THIS SHOULD LEND ITSELF
TO VERTICAL UPDRAFTS THAT ARE FAIRLY SHORT LIVED, ESPECIALLY WHEN
DISPLACED FROM HIGH TERRAIN OROGRAPHICS, BUT GENERATING OUTFLOWS
O'PLENTY. RAP FORECAST SOUNDINGS SHOW INVERTED VS UP TO ABOUT 700
MB BUT ALSO DRY AIR ALOFT WITH HEALTHY MLCAPE UP TO THE EL. IT
LOOKS LIKE ANY UPDRAFTS THAT CAN REACH THE 17-20KFT LEVEL WILL
START ENTRAINING DRY AIR UPON COLLAPSE AND BE THE CANDIDATES FOR
GUSTY OUTFLOW WINDS. WITH THE AMOUNT OF INSTABILITY DEPICTED IN
THE RAP, CAN'T RULE OUT A SVR OR TWO FOR THE STRONGEST UPDRAFTS.
THAT BEING SAID, THE 00Z HREF HAS A FAIRLY STRONG SIGNAL FOR AT
LEAST 30+ KT WIND GUSTS ORIGINATING FROM NORTH-CENTRAL ARIZONA
PUSHING WEST INTO MOHAVE, AS WELL AS SOUTHWEST UTAH PUSHING INTO
NORTHEAST CLARK OR EASTERN LINCOLN TONIGHT AS WELL.
LONG TERM
THURSDAY THROUGH THE WEEKEND.
THE FOCUS OF THE LONG TERM IS THE REMNANTS OF THE TROPICAL SYSTEM
THAT IMPACTED THE TEXAS GULF COAST A FEW DAYS AGO. THE
AFOREMENTIONED PACIFIC TROUGH WILL SHIFT NORTHEAST AND EC/GEFS
MEANS INDICATE A BROAD AREA OF HIGH PRESSURE SETTING UP OFF THE
COAST. THIS WOULD SERVE TO EFFECTIVELY BLOCK THE TROPICAL MOISTURE
FROM PROGRESSING FARTHER WEST AND INTO THE PACIFIC, BUT INSTEAD
HALT ITS MOTION OVER SOUTHERN ARIZONA AND SET THE STAGE FOR A
MULTIPLE PERIODS OF HEAVY RAINFALL OVER THE SOUTHERN HALF OF THE
STATE, FROM THURSDAY NIGHT INTO SUNDAY. THAT HIGH PRESSURE OVER
THE PACIFIC MAY CONTINUE TO BUILD INTO THE WEEKEND AND SHIFT
SLOWLY EASTWARD, WHEN IT DOES, THE TROUGHING OVER ARIZONA DEFORMS
AND STRETCHES OUT, LESSENING THE FOCUSED LIFTING OVER SOUTHERN
ARIZONA BUT DISTRIBUTING VORT MAXES ACROSS MUCH OF THE STATE. THIS
SHOULD SERVE TO BRING WIDESPREAD HEAVY RAINFALL ACROSS MUCH OF THE
STATE, INCLUDING MOHAVE COUNTY, AND PERHAPS AS FAR WEST AS THE
MOJAVE PRESERVE AND THE CRV. AS OF NOW, GEFS/EC/GEM AGREE IN
KEEPING THE HEAVIEST QPF ALONG AND SOUTH OF THE I-40 CORRIDOR, BUT
THIS WOULD PUT MANY OF THE HARDEST HIT AREAS OF MOHAVE COUNTY IN
THE AREA OF CONCERN FOR FURTHER FLASH FLOODING IMPACTS SUCH AS
GOLDEN VALLEY, KINGMAN, AND THE HUALAPAI MOUNTAINS.
THERE IS STILL SOME UNCERTAINTY HOWEVER, AS THE RIDGE COULD BUILD
IN QUICKER AND PUSH THE MOISTURE SWATH FARTHER EAST PER SOME OF
THE MINORITY CLUSTERS. THERE DOES APPEAR TO BE A PRETTY STARK
POP/QPF GRADIENT AS A RESULT OF THIS RIDGE BUILDING IN, WHICH IS
CURRENTLY KEEPS MUCH OF INYO, ESMERALDA, NYE, AND WESTERN SAN
BERNARDINO MORE OR LESS DRY. BUT IF THE FORECAST TRENDS WETTER OR
EVEN MAINTAINS ITS CURRENT EXPECTATIONS, THEN WOULD THINK THAT A
FF WATCH AGAIN FOR AT LEAST MOHAVE LOOKS LIKE A SAFE BET FOR
FRIDAY AND SATURDAY.
AVIATION...FOR HARRY REID
SCATTERED THUNDERSTORMS ARE EXPECTED
ONCE AGAIN TODAY MAINLY OVER THE HIGHER TERRAIN SURROUNDING THE LAS
VEGAS VALLEY. WHILE THERE IS A SLIGHT CHANCE THAT STORMS COULD
DIRECTLY AFFECT THE TERMINAL LATE THIS AFTERNOON AND EARLY EVENING,
A MORE LIKELY SCENARIO IS FOR GUSTY WINDS FROM OUTFLOWS TO MOVE
THROUGH THE AREA THIS EVENING, AND THIS IS INCLUDED IN THE TAF.
OUTSIDE OF THUNDERSTORM ACTIVITY TODAY, WINDS SHOULD BE LIGHT WITH
SKIES SCT AOA 12KFT. ADDITIONAL THUNDERSTORM ACTIVITY IS EXPECTED
ON THURSDAY, POSSIBLY STARTING EARLIER IN THE DAY NEAR 18Z.
FOR THE REST OF SOUTHERN NEVADA, NORTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...SCATTERED THUNDERSTORMS ARE EXPECTED AREA-WIDE ONCE
AGAIN TODAY. STORMS ARE EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN
SURROUNDING KBIH BY MID-AFTERNOON, POSSIBLY DIRECTLY AFFECTING THE
FIELD AFTER 22Z. STORMS WILL BE MORE SCATTERED IN NATURE NEAR KDAG
WITH THE ACTIVITY EXPECTED MAINLY DURING THE LATE AFTERNOON OR EARLY
EVENING. THE LOWER COLORADO RIVER VALLEY SITES WILL SEE THE BEST
CHANCE OF STORMS DURING THE EVENING HOURS. OUTSIDE OF THUNDERSTORM
ACTIVITY, LIGHT WINDS FAVORING TYPICAL DIURNAL TRENDS ARE EXPECTED
ALONG WITH SKIES SCT AOA 12KFT.
SPOTTER INFORMATION STATEMENT
SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING
PROCEDURES.
DISCUSSION...TB3
AVIATION...PLANZ
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