224
FXUS65 KVEF 131804
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1105 AM PDT THU AUG 13 2020
SYNOPSIS
CONSIDERABLE MID AND HIGH CLOUDS WILL SPREAD UP ACROSS
THE REGION TODAY. ISOLATED THUNDERSTORMS CAN BE EXPECTED OVER THE
SOUTHERN SIERRA AND PARTS OF NORTHWEST ARIZONA. MOSTLY SUNNY SKIES
WILL RETURN FRIDAY AND TEMPERATURES WILL CLIMB WELL ABOVE NORMAL
LEADING TO EXCESSIVE HEAT THROUGH THE WEEKEND AND MUCH OF NEXT WEEK
UNDER A STRONG AREA OF HIGH PRESSURE SETTING UP OVER THE WESTERN
STATES.
UPDATE
INCREASED CLOUD COVER HAS ENTERED THE REGION THIS MORNING,
ENCOMPASSING SOUTHERN NEVADA, SOUTHEASTERN CALIFORNIA AND
NORTHWESTERN ARIZONA DUE TO ELEVATED MOISTURE FROM THE REMNANTS OF
ELIDA. ADDITIONALLY, SMOKE LINGERS OVER SOUTHERN NEVADA THIS
MORNING, WHICH IS A COMBINATION FROM THE LAKE FIRE IN SOCAL AS WELL
AS A FEW FIRES IN THE NW BAJA. THESE CLOUDS ARE EXPECTED TO MOVE OUT
OF THE REGION TONIGHT, ALLOWING FOR A SUNNY START TO THE WEEKEND.
MOISTURE FROM FORMER HURRICANE ELIDA WILL NOT ONLY BRING AN INCREASE
IN CLOUD COVER, BUT THE CHANCE FOR SOME LIGHT SHOWERS IN THE HIGHER
ELEVATIONS, PARTICULARLY OVER THE SIERRA AND CENTRAL MOHAVE COUNTY
THIS AFTERNOON. AN ISOLATED LIGHTNING STRIKE IS NOT OUT OF THE
QUESTION, WHICH COULD ELEVATE FIRE DANGER CONCERNS. THOUGH SHOWERS
ARE POSSIBLE, DUE TO THE DRY LOW LEVELS, NOT MUCH IN THE WAY OF
MEASURABLE RAINFALL IS EXPECTED.
I INCREASED THE CHANCE OF PRECIPITATION IN SAN BERNARDINO COUNTY,
THE EASTERN SIERRA, AND CENTRAL MOHAVE COUNTY FOR THIS AFTERNOON
WITH THIS MORNING UPDATE. THE REST OF THE FORECAST LOOKS TO BE IN
GOOD SHAPE; NO ADDITIONAL CHANGES WERE MADE.
NO UPDATES HAVE BEEN MADE TO THE CURRENT EXCESSIVE HEAT WARNINGS NOR
HEAT ADVISORIES IN EFFECT, BUT WILL REVISIT THE POSSIBILITY OF AN
EXPANSION TO ESMERALDA AND SOUTHERN NYE COUNTIES AS WELL AS NORTHERN
MOHAVE COUNTY. DUE TO THE LONG-DURATION NATURE OF THIS HEAT WAVE,
EXPECTING TO DIVE FURTHER INTO CONVERSATION WITH NEIGHBORING OFFICES
REGARDING EXTENDING THESE HEAT HEADLINES THROUGH AT LEAST THE MIDDLE
OF NEXT WEEK.
PREVIOUS DISCUSSION
320 AM PDT THU AUG 13 2020/
SHORT TERM
TODAY THROUGH FRIDAY.
CONSIDERABLE CLOUD COVER TODAY THROUGH THIS EVENING WILL BE THE MOST
NOTABLE CHANGE IN THE WEATHER AS MID AND HIGH LEVEL MOISTURE IS
PULLED UP ACROSS OUR REGION FROM POST-TROPICAL CYCLONE ELIDA...
WHICH WAS DISSIPATED WELL WEST OF BAJA CALIFORNIA. THE CHANCE OF ANY
MEASURABLE PRECIPITATION WILL BE LESS THAN 10 PERCENT ACROSS MOST OF
THE REGION. THE EXCEPTIONS WILL BE THE SOUTHERN SIERRA AND OWENS
VALLEY AND ALSO OVER EASTERN MOHAVE COUNTY WHERE SUFFICIENT MOISTURE
AND INSTABILITY WILL SUPPORT ISOLATED THUNDERSTORMS THIS AFTERNOON.
SKIES WILL CLEAR TONIGHT AS THE SWATH OF MOISTURE LIFTS AWAY TO THE
NORTH ALLOWING MOSTLY SUNNY SKIES TO RETURN FRIDAY AS HIGH PRESSURE
OVER ARIZONA AND NEW MEXICO BEGINS TO EXPAND AND STRENGTHEN OVER
SOUTHERN NEVADA. TEMPERATURES WILL CLIMB 4-5 DEGREES FRIDAY AND THIS
BEGINS A PROLONGED PERIOD OF WELL ABOVE NORMAL TEMPERATURES
APPROACHING RECORD VALUES. THE EXCESSIVE HEAT WARNING WHICH GOES
INTO EFFECT FRIDAY REMAINS UNCHANGED.
LONG TERM
SATURDAY THROUGH WEDNESDAY.
GEFS ALONG WITH THE ECMWF ENSEMBLE GUIDANCE REMAINS CONSISTENT
ADVERTISING THAT A STRONG AREA OF HIGH PRESSURE WILL STAY POSITIONED
OVER THE REGION THIS WEEKEND THROUGH MOST OF NEXT WEEK. THIS WILL
LEAD TO A PROLONGED HEATWAVE WITH DAILY RECORD HIGHS, AS WELL AS
HIGH MINIMUM TEMPERATURES POTENTIALLY BEING TIED OR BROKEN. FOR LAS
VEGAS, WE COULD POTENTIALLY SEE UP TO 6 DAYS WITH HIGH TEMPERATURES
GREATER OR EQUAL TO 110 DEGREES. THE CURRENT RECORD STRETCH OF DAYS
FOR AUGUST IS 7 DAYS (8/7/1940-8/13/1940). WE HAVE HAD 6 TIMES WERE
THE LENGTH OF DAYS WAS EITHER 5 OR 6. RECORDS FOR LAS VEGAS DATE
BACK TO 1937. THE EXCESSIVE HEAT WARNING RUNS THROUGH MONDAY BUT
WILL LIKELY NEED TO BE EXTENDED BASED ON HEATRISK VALUES WHICH KEEP
MOST OF THE AREA IN HIGH-VERY HIGH RISK.
AS FAR AS ANY PRECIPITATION. OPERATIONAL ECMWF CONTINUES TO INDICATE
THAT SOME MID-LEVEL MOISTURE WILL BECOME TRAPPED AND CIRCULATE
UNDERNEATH THE STRONG HIGH CENTER. HOWEVER, NOT OVERLY IMPRESSED BY
THE AMOUNT OF INSTABILITY AS LOW LEVELS REMAIN DRY WITH LITTLE
PENETRATION OF H85 DEWPOINTS IN EXCESS OF 8 DEGREE C NORTHWARD INTO
THE MOJAVE DESERT OR SOUTHERN GREAT BASIN. GEFS LOOKS MODESTLY MORE
AGGRESSIVE WHICH DOES GENERATE AT LEAST A SLIGHT CHANCE OF
THUNDERSTORMS OVER SOME OF OUR HIGHER TERRAIN EACH AFTERNOON AND
EVENING. THESE STORMS WOULD PRODUCE MORE WIND AND LIGHTNING THAN
RAIN SO NEW FIRE STARTS ARE A CONCERN AS WELL.
AVIATION...FOR MCCARRAN
BY EARLY THIS AFTERNOON, WINDS WILL
SHIFT TO THE SOUTHWEST AT SPEEDS OF AROUND 9-12 KNOTS WITH
INTERMITTENT GUSTS OF 15-20 KNOTS POSSIBLE. THERE ARE LOW-END
CHANCES FOR A STRAY SHOWER OR STORM TO DEVELOP OVER THE HIGHER
ELEVATIONS OF CLARK COUNTY BETWEEN 20Z-01Z WHICH COULD PUSH SOME
GUSTY, OUTFLOW WINDS INTO THE VALLEY LATER THIS AFTERNOON. THIS
SCENARIO IS UNLIKELY AND BETTER CHANCES REMAIN WELL TO THE EAST
ACROSS NORTHWEST ARIZONA. SCT-BKN MID/HIGH CLOUDS WILL MOVE IN BY
12Z AND CONTINUE FOR MUCH OF THE DAY AT HEIGHTS OF 15K FEET OR
ABOVE.
FOR THE REST OF SOUTHERN NEVADA, NORTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...AFTERNOON WIND SPEEDS SHOULD REMAIN AROUND 10 KNOTS
WITH A FEW GUSTS OF 15-20 KNOTS POSSIBLE. BEST CHANCES TO SEE A
SHOWER OR STORM WILL REMAIN OVER THE SIERRA (NEAR KBIH) AND MOHAVE
COUNTY THIS AFTERNOON (BUT EAST OF KIFP/KEED). A STRAY SHOWER OVER
THE HIGHER ELEVATIONS OF CLARK COUNTY AND THE REMAINDER OF INYO
COUNTY CAN'T BE RULED OUT THOUGH. GUSTY, ERRATIC WINDS WILL BE THE
MAIN THREAT WITH ANY ACTIVITY THAT DEVELOPS TODAY, IF ANY. MID/HIGH
CLOUDS STREAM IN FROM THE SOUTH THIS MORNING WITH SCT-BKN CLOUD
DECKS AT OR ABOVE 12K FEET.
CLIMATE
DAILY RECORD HIGH MAXIMUM TEMPERATURES
FRI 8/14 SAT 8/15 SUN 8/16 MON 8/17
LAS VEGAS, NV 111 (2016) 111 (2002)* 113 (1939)* 111 (1939)*
BISHOP, CA 106 (2002) 105 (2002)* 106 (1994)* 106 (2015)
BARSTOW, CA 112 (2002) 112 (2002)* 114 (1994)* 111 (2015)*
NEEDLES, CA 117 (2012)* 118 (2019)* 118 (2015)* 117 (1892)*
KINGMAN, AZ 109 (1933) 106 (1933)* 110 (1933)* 106 (2001)*
DEATH VALLEY 124 (2002) 124 (2002)* 125 (1994)* 124 (2001)*
DAILY RECORD HIGH MINIMUM TEMPERATURES
FRI 8/14 SAT 8/15 SUN 8/16 MON 8/17
LAS VEGAS, NV 86 (2007)* 86 (2016)* 88 (2008)* 89 (2015)*
BISHOP, CA 67 (2015) 65 (1958) 67 (1992) 65 (1992)*
BARSTOW, CA 81 (1983)* 83 (1996)* 81 (1994)* 82 (2012)*
NEEDLES, CA 93 (1996)* 92 (1962)* 93 (1892)* 94 (1903)
KINGMAN, AZ 79 (1996) 78 (1972)* 77 (1917)* 81 (1903)*
DEATH VALLEY 100 (1924) 97 (2008)* 98 (2008)* 99 (2013)*
*-CURRENT FORECAST MAY BE CLOSE TO CURRENT RECORD VALUES.
SPOTTER INFORMATION STATEMENT
SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING
PROCEDURES.
UPDATE...VARIAN
SHORT TERM...ADAIR
LONG TERM...PIERCE
AVIATION/CLIMATE...GUILLET/TB3
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