Area Forecast Discussion
Issued by NWS Las Vegas, NV

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000
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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