156
FXUS65 KVEF 200730
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1230 AM PDT TUE OCT 20 2026
KEY MESSAGES
* AN INCOMING TROUGH BRINGS WIDESPREAD RAIN AND MOUNTAIN SNOW
CHANCES, GUSTY WINDS, AND COOLING TEMPERATURES THIS WEEK.
* INCREASING CONFIDENCE FOR A DRY CONDITIONS AND SEASONABLE
TEMPERATURES THIS WEEKEND.
DISCUSSION
THROUGH MONDAY.
OUR NEXT SYSTEM BEGINS TO ENCROACH ON THE REGION TODAY IN THE FORM
OF A CLOSED LOW SPINNING OFF THE CA COAST. OVER THE REMAINDER OF THE
WORK WEEK, IT WILL SLOWLY MOVE THROUGH THE FORECAST AREA, EVENTUALLY
TRANSITIONING TO AN OPEN WAVE AS IT PHASES WITH A PACNW SHORTWAVE.
NORTHWARD MOISTURE ADVECTION AND UPPER-LEVEL DIVERGENCE IN THE LEFT
EXIT REGION OF A JET STREAK WILL SPUR ISOLATED TO SCATTERED SHOWERS
AND STORM TODAY. BEST CHANCES (25-50%) ARE GENERALLY NORTHWEST OF I-
15 AND IN MOHAVE COUNTY. THE SLOW-MOVING NATURE OF THE SYSTEM
RESULTS IN A SIMILAR SETUP ON WEDNESDAY. PRECIPITATION CHANCES ARE
HIGHER ACROSS THE BOARD (+25%) ON WEDNESDAY DUE TO ADDITIONAL
MOISTURE AND COLDER AIR ALOFT, BUT THE SAME PLACES WILL BE FAVORED.
FINALLY, THE MAIN VORT MAX ASSOCIATED WITH THE LOW SWINGS THROUGH ON
THURSDAY, BRINGING THE BEST POTENTIAL FOR WIDESPREAD PRECIPITATION
(60-90% IN MOST LOCATIONS). HOWEVER, THE PHASING WITH THE PACNW
SHORTWAVE SENDS A SECONDARY VORT MAX DOWN THE BACKSIDE AND KEEPS THE
TROUGH OVERHEAD THROUGH THE END OF THE WORK WEEK. AS A RESULT,
ISOLATED TO SCATTERED SHOWER CHANCES LINGER ON FRIDAY.
OVERALL, BEST ODDS OF PRECIPITATION IMPACTS ARE IN THE SOUTHERN
GREAT BASIN, INYO COUNTY, AND NORTHERN MOHAVE COUNTY WHERE CHANCES
OF 1"+ RANGE FROM 25-50%. THUNDERSTORM DEVELOPMENT WILL AID THIS
POTENTIAL, BUT TRAINING CONVECTION IS GOING TO BE REQUIRED GIVEN THE
FLOW ALOFT. THE BIGGEST "BUST" POTENTIAL IS IN THE SOUTHERN MOJAVE
DESERT (THINK OF THE AREA BOUNDED BETWEEN TWENTYNINE PALMS, BARSTOW,
LAS VEGAS, KINGMAN, AND LAKE HAVASU), WHERE MODELS HAVE THIS ZONE
KIND OF CAUGHT IN A DRY SLOT BETWEEN THE TWO MAIN PRECIPITATION
REGIMES. THIS AREA HAS A 40-70% CHANCE OF 0.10" OR LESS. THERE IS
A MINOR WINTRY COMPONENT OF THIS SYSTEM AS SNOW LEVELS BOTTOM OUT
AROUND 8KFT IN THE SIERRA. HOWEVER, AS THEY DO, PRECIPITATION WILL
LARGELY BE DONE, SO ANY IMPACTS ARE EXPECTED TO BE CONFINED TO
ELEVATIONS ABOVE 9KFT WHERE FORECAST SNOW TOTALS RANGE FROM 3-10"
(THE HIGHER AMOUNTS NEAR THE CREST). LASTLY, GUSTY SOUTH-SOUTHWEST
WINDS (20-40 MPH) WILL ACCOMPANY THIS SYSTEM AS WELL, BUT ANY
IMPACTS SHOULD BE CONFINED TO THE LOCAL LAKES.
BY SATURDAY, ENSEMBLE GUIDANCE HAS OUR AREA FIRMLY ON THE BACKSIDE
OF THE TROUGH. WE WILL SEE A DRY NORTHERLY FLOW THAT QUICKLY SCOURS
OUT MOISTURE AND PRECIPITATION CHANCES, AND PRODUCES SOME GUSTY
NORTH WINDS. ON SUNDAY AND MONDAY, THE FLOW WEAKENS AND BECOMES MORE
ZONAL/SOUTHWESTERLY, KEEPING US DRY WITH LIGHT WINDS AND SLIGHTLY
BELOW-NORMAL TEMPERATURES.
AVIATION...FOR HARRY REID...FOR THE 06Z FORECAST PACKAGE
FAVORABLE CONDITIONS ARE EXPECTED THROUGH TUESDAY, WITH WINDS
FOLLOWING TYPICAL DIURNAL DIRECTIONAL TRENDS AND SPEEDS GENERALLY
REMAINING LESS THAN 8 KNOTS. NORTHEAST WINDS TUESDAY MORNING WILL
TURN MORE SOUTHEASTERLY BY 21Z. THERE IS A 15 PERCENT CHANCE OF
SEEING AN ISOLATED GUST TO 12 KNOTS ONCE WINDS TURN SOUTHEAST, BUT
ANY GUSTS SHOULD BE SHORT-LIVED. ISOLATED CONVECTION IS POSSIBLE
DURING THE AFTERNOON AND EARLY EVENING OVER THE HIGHER TERRAIN
SURROUNDING THE VALLEY, BUT NO PRECIPITATION IS EXPECTED NEAR THE
FIELD. VFR CONDITIONS WILL PREVAIL THROUGH TUESDAY NIGHT, WITH SCT
CLOUDS AND BASES GENERALLY REMAINING AOA 10KFT AGL.
FOR THE REST OF SOUTHERN NEVADA, NORTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...FOR THE 06Z FORECAST PACKAGE...LIGHT WINDS FOLLOWING
TYPICAL DIURNAL DIRECTIONAL TRENDS ARE EXPECTED AT AREA TAF SITES
OVERNIGHT INTO TUESDAY MORNING. MOST SITES WILL SEE LIGHT WINDS
CONTINUE INTO TUESDAY AFTERNOON. ONE EXCEPTION WILL BE ACROSS THE
NORTHERN OWENS VALLEY, INCLUDING KBIH, WHERE SOUTHERLY WINDS GUSTING
30 TO 35 KNOTS ARE EXPECTED DURING THE AFTERNOON AND EARLY EVENING.
GUSTY EASTERLY WINDS ARE ALSO EXPECTED ACROSS THE WESTERN MOJAVE
DESERT, INCLUDING KDAG. ISOLATED AREAS OF CONVECTION WILL BE SEEN
OVER HIGHER TERRAIN DURING THE AFTERNOON AND EARLY EVENING, BUT NO
DIRECT IMPACTS ARE EXPECTED AT AREA TERMINALS.
SPOTTER INFORMATION STATEMENT
SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING
PROCEDURES.
DISCUSSION...WOODS
AVIATION...PLANZ
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