Weather Service Report


653 
FXUS65 KVEF 010608 CCA
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1008 PM PST SAT FEB 28 2015

.SYNOPSIS...A STORM SYSTEM CONTINUES TO DROP SOUTH ACROSS CALIFORNIA 
RESULTING IN GUSTY WINDS AND SHOWERS ACROSS PORTIONS OF THE AREA. AS 
THE STORM DROPS OFF THE COAST OF SOUTHERN CALIFORNIA ON SUNDAY IT 
WILL PUSH A BAND OF STEADIER PRECIPITATION INTO THE MOJAVE DESERT 
THAT WILL LAST THROUGH SUNDAY NIGHT INTO MONDAY MORNING. ELSEWHERE 
ACROSS THE AREA ON SUNDAY SHOWERS ARE POSSIBLE. UNSETTLED WEATHER IS 
POSSIBLE ACROSS THE AREA INTO TUESDAY NIGHT BEFORE A DRYING AND 
WARMING TREND TAKES PLACE. 
&&

.UPDATE...THE LATEST RADAR WAS NOT TOO IMPRESSIVE WITH MEANINGFUL 
RETURNS ACROSS THE AREA THIS EVENING. BASED ON THE OPERATIONAL 
MODELS AND THE HRRR AS WELL AS RADAR TRENDS, I ELECTED TO TRIM BACK 
POPS FURTHER ACROSS THE MOJAVE DESERT FOR THE REST OF THE OVERNIGHT 
PERIOD. WHILE THE THREAT OF SHOWERS IN THE SOUTHERN GREAT BASIN DOES 
NOT LOOK TO IMPRESSIVE AT THIS TIME, MODELS SHOW ENOUGH MID-LEVEL 
MOISTURE AND ENERGY ACROSS THE AREA OVERNIGHT THAT IT CANNOT BE 
COMPLETELY DISCOUNTED EITHER AND THUS POPS THERE WERE LEFT AS IS.

FOR THE SUNDAY AFTERNOON-MONDAY EVENT, THINGS STILL LOOK GOOD FOR A 
BAND OF STEADIER PRECIPITATION TO IMPACT THE SOUTHEASTERN AND 
EVENTUALLY EASTERN THIRD OF THE AREA. THE HRRR APPEARS TOO 
AGGRESSIVE SPREADING THIS BAND ON BASED ON THE LATEST SATELLITE 
IMAGERY BUT BY THE AFTERNOON AND ESPECIALLY EVENING THIS BAND SHOULD 
MAKE PROGRESS INTO OUR AREA. A FEW CONCERNS WILL BE POTENTIAL HYDRO 
ISSUES IN MOHAVE COUNTY FOR MINOR FLOODING IN POOR DRAINAGE AREAS AS 
WELL AS THE NEED FOR WINTER WEATHER HEADLINES IN LINCOLN COUNTY 
WHERE SNOW LEVELS ARE EXPECTED TO BE 5500 FEET AND FALL TO 5000 
FEET. AREAS NORTH OF PIOCHE AS WELL AS TOWARD THE UTAH BORDER SUCH 
AS PANACA SUMMIT COULD SEE SEVERAL INCHES OF SNOW IN THIS TIME FRAME 
MAKING FOR TRICKY TRAVEL.
&&

.AVIATION...FOR MCCARRAN...SOUTH TO SOUTHWEST WINDS AT 8-12 KTS ARE 
EXPECTED OVERNIGHT. FEW-SCT CLOUDS AOA 7K FEET WITH CLOUDS 
INCREASING OVERNIGHT INTO SUNDAY WITH BASES LOWERING THROUGH THE DAY 
ON SUNDAY. THERE IS POTENTIAL FOR A PERIOD OF STEADY RAIN IMPACTING 
THE LAS VEGAS VALLEY LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT. CIGS 
BELOW 5K FEET AND REDUCED VSBY ARE POSSIBLE WITH MOUNTAIN 
OBSCURATIONS LIKELY. RAIN SHOULD TAPER OFF TO SHOWERS BY MONDAY 
AFTERNOON. 

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST 
CALIFORNIA...SHOWERS WILL BE AROUND OVERNIGHT MAINLY NORTH OF A 
KDAG-KCDC LINE. CIGS AS LOW AS 4K-8K FEET ARE POSSIBLE IN AND NEAR 
ANY SHOWERS. OTHERWISE EXPECT DRY CONDITIONS WITH FEW-SCT CLOUDS AOA 
7K-10K FEET. WINDS SHOULD FAVOR TYPICAL DIURNAL TRENDS. FOR SUNDAY, 
EXPECT WINDS MAINLY 10 KTS OR LESS WITH WINDS FAVORING TYPICAL 
DIURNAL DIRECTIONAL TRENDS. CLOUDS SHOULD INCREASE WITH BASES 
LOWERING THROUGH THE DAY. STEADIER PRECIPITATION IS EXPECTED AFTER 
21Z SUNDAY INTO SUNDAY NIGHT SOUTH OF KDAG-KELY LINE WITH SNOW 
LEVELS BETWEEN 5500 AND 6500 FEET. ISO-SCT SHOWERS ARE EXPECTED 
NORTHWEST OF THIS LINE. EXPECT CIGS BELOW 5K FEET AND VSBY REDUCED 
TO MVFR OR LOWER AT TIMES. MOUNTAIN OBSCURATIONS ARE LIKELY. STEADY 
PRECIPITATION SHOULD TAPER TO SHOWERS BETWEEN 12Z AND 18Z ON MONDAY.
&&

.PREVIOUS DISCUSSION...
ISSUED AT 230 PM PST SAT FEB 28 2015

.SHORT TERM...THROUGH MONDAY NIGHT.

OUR MID/UPPER LEVEL LOW PRESSURE SYSTEM IS CURRENTLY TRACKING SOUTH 
OVER WESTERN CALIFORNIA. UNDER A DESTABILIZING ATMOSPHERE AND UPPER 
LEVEL FORCING...SCATTERED SHOWERS HAVE DEVELOPED ACROSS PORTIONS OF 
SOUTHERN NEVADA AND NORTHWEST ARIZONA. THIS ACTIVITY SHOULD CONTINUE 
AND MAY INCREASE IN COVERAGE A LITTLE THROUGH THIS EVENING. THERE 
HAVE BEEN A FEW LIGHTNING STRIKES OVER SOUTHWEST UTAH AND CENTRAL 
NYE COUNTY...WHICH WILL REMAIN POSSIBLE THROUGH THIS EVENING. 
THEN...THE LATEST HIRES GUIDANCE CONTINUES TO INDICATE A MORE 
NORTHERLY SHIFT LATER THIS EVENING AND COVERAGE DIMINISHING QUITE A 
BIT LATE TONIGHT. DID DECREASE POPS...BUT MIGHT NOT BE LOW ENOUGH IN 
MANY LOCATIONS IF THE GUIDANCE IS CORRECT. WILL SEE HOW THINGS TREND 
THROUGH THE EVENING HOURS. DID INCREASE POPS ACROSS ESMERALDA AND 
CENTRAL NYE OVERNIGHT AS THE FORCING AND PRECIP APPEARS TO FOCUS 
THERE AS THE UPPER LOW SHIFTS SOUTH. SNOW LEVELS ARE AROUND 
5500-6500 FEET AND ARE EXPECTED TO DROP TO 4500-5500 FEET BY SUNDAY 
MORNING ACROSS OUR NORTH. ANY PRECIP ACROSS OUR NORTH WOULD FALL AS 
SNOW AROUND 5000-5500 FEET AND ACCUMULATE GENERALLY 1-3 
INCHES...LOCALLY HIGHER ABOVE 7000 FEET. FARTHER SOUTH WE FIND GUSTY 
WEST-SOUTHWEST WINDS THIS AFTERNOON...WHICH WILL LAST INTO THIS 
EVENING. THE WIND ADVISORY REMAINS IN EFFECT. WIND SPEEDS SHOULD 
DECREASE OVERNIGHT. 

AS THE LOW CONTINUES TO DROP SOUTH...IT WILL PIVOT AND TAP INTO A 
PLUME OF SUBTROPICAL MOISTURE AND DIRECT IT NORTH ACROSS THE LOWER 
SOUTHERN CALIFORNIA DESERTS AND TOWARD THE COLORADO RIVER VALLEY 
SUNDAY MORNING INTO SUNDAY NIGHT. LATEST OPERATIONAL MODELS HAVE NOT 
VARIED TOO MUCH FROM LAST NIGHTS MODEL RUNS. THE PLUME OF MOISTURE 
IS FOCUSED ON MOHAVE COUNTY WITH THE WESTERN EDGES EXTENDING INTO 
LINCOLN...CLARK...AND SAN BERNARDINO COUNTIES. BELIEVE THERE WILL BE 
A SHARP CUTOFF OF THE HEAVIER PRECIP ON THE WESTERN SIDE...WHICH 
WILL LIKELY HAVE TO BE FINE-TUNED WHEN THE PRECIP BAND FINALLY 
FORMS. FARTHER WEST WOULD SEE MORE SHOWERY ACTIVITY. SUNDAY 
AFTERNOON THROUGH SUNDAY NIGHT WOULD BE THE BEST CHANCE OF RAIN AND 
HIGH ELEVATION SNOW...SO DID NOT MAKE MANY CHANGES TO THE RUNNING 
SUNDAY-SUNDAY NIGHT FORECAST. WITH THE PRECIP ORIGINATING FROM A 
WARM SOURCE REGION...SNOW LEVELS WILL BE RATHER HIGH ACROSS SOUTHERN 
MOHAVE COUNTY /GREATER THAN 6500 FEET/ WITH LEVELS OF 5500-6500 FEET 
ANTICIPATED IN NORTHERN MOHAVE COUNTY SUNDAY THROUGH SUNDAY NIGHT. 
WILL HAVE TO KEEP AN EYE ON POTENTIAL SNOW ACCUMULATIONS ACROSS THE 
HIGHER ELEVATIONS OF NORTHERN MOHAVE COUNTY SUNDAY NIGHT INTO MONDAY 
MORNING WITH THAT MOISTURE TAP...BUT RIGHT NOW NOT LOOKING LIKE ANY 
HEADLINES ARE NEEDED. WEST OF MOHAVE COUNTY...SNOW LEVELS SHOULD 
RANGE BETWEEN 4500-5500 FEET.

DID INCREASE QPF ACROSS MOHAVE COUNTY SOME MORE...WITH THE POTENTIAL 
FOR OVER AN INCH OF LIQUID PRECIPITATION SUNDAY THROUGH MONDAY. AS 
MENTIONED IN THE PREVIOUS DISCUSSION...THIS MAY RESULT IN MINOR 
FLOODING IN POOR DRAINAGE AREAS AS WELL AS RAPID RISES IN WASHES. 
WHILE THE MAIN PLUME OF MOISTURE CONTINUES TO TAKE AIM ON MOHAVE 
COUNTY...CANNOT RULE OUT ADDITIONAL SHIFTS EITHER WEST OR EAST. FOR 
EXAMPLE...THE 18Z NAM CAME IN A LITTLE FARTHER WEST. NOT SOLD ON 
THIS SOLUTION THOUGH AS THE 18Z RUN YESTERDAY DID THE SAME THING 
BEFORE TRENDING THE PLUME BACK OVER MOHAVE COUNTY LAST NIGHT. 
SO...PLEASE KEEP UP TO DATE WITH THE LATEST FORECAST INFORMATION. 
ALSO FOR MONDAY...WEST-SOUTHWEST WINDS WILL BECOME GUSTY ONCE AGAIN. 
NOT LOOKING AT WIND ADVISORY LEVEL WINDS AT THIS TIME BUT GUSTY 
NONETHELESS.

AS FOR TEMPERATURES...THE LAS VEGAS VALLEY HAS REACHED THE LOWER 60S 
FOR MANY LOCATIONS AS OF THIS WRITING. THIS SHOULD ALLOW FEBRUARY TO 
GO DOWN AS THE WARMEST ON RECORD AS WELL AS THE WARMEST 
METEOROLOGICAL WINTER ON RECORD FOR LAS VEGAS. QUITE IMPRESSIVE! 
TOMORROW SHOULD BE A FEW DEGREES COOLER ACROSS THE ENTIRE REGION 
WITH SIMILAR TEMPERATURES EXPECTED TO CONTINUE MONDAY.

.LONG TERM...TUESDAY THROUGH SATURDAY.

A QUICK OVERVIEW OF THE EXTENDED: MODELS FORECAST AN AREA OF LOW 
PRESSURE ALONG THE SOUTHERN CAL COAST EARLY TUESDAY MORNING MOVING 
TO NORTHERN BAJA BY WEDNESDAY MORNING. ADDITIONAL SHORTWAVE ENERGY 
SLIDES DOWN ALONG THE WEST COAST WEDNESDAY AND MERGES WITH THE LOW 
THURSDAY AND NUDGES IT EASTWARD. HIGH PRESSURE BUILDS OVER THE 
SOUTHWEST FRIDAY AND IS THEN PUSHED EAST SATURDAY AS A PACIFIC 
TROUGH APPROACHES FROM THE WEST. 

SHOWER ACTIVITY COULD LINGER THROUGH TUESDAY BUT ANY PRECIPITATION 
AMOUNTS WILL BE LIGHT. SKIES WILL BEGIN TO CLEAR...ESPECIALLY LATE 
TUESDAY WITH A BATCH OF HIGH CLOUDS POSSIBLE WEDNESDAY AS AN UPPER 
DISTURBANCE MOVES SOUTH ALONG THE COAST. DRY AND MAINLY CLEAR 
CONDITIONS ARE EXPECTED THURSDAY AND FRIDAY BEFORE MORE HIGH CLOUDS 
MOVES INTO THE AREA SATURDAY. 

NORTH WINDS ARE EXPECTED TUESDAY AND WEDNESDAY ACROSS MUCH OF THE 
AREA THEN LINGERING ALONG THE COLORADO RIVER VALLEY THURSDAY AND 
FRIDAY. COOL CONDITIONS WILL LINGER THROUGH WEDNESDAY...WITH TEMPS 
REMAINING 8-10 DEGREES BELOW NORMAL FOLLOWED BY A WARMING TREND 
THROUGH THE REST OF THE WEEK. TEMPERATURES BY FRIDAY ARE EXPECTED TO 
BE RIGHT AROUND NORMAL.
&&

.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE REQUESTED TO REPORT 
ANY SIGNIFICANT WEATHER ACCORDING TO STANDARD OPERATING PROCEDURES 
TODAY THROUGH TUESDAY NIGHT. 
&&

$$

UPDATE/AVIATION...STACHELSKI
PREVIOUS...PADDOCK/SALMEN

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