AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
334 AM PST TUE FEB 9 2010

.SYNOPSIS...A COLD STORM SYSTEM WILL MOVE ALONG THE CALIFORNIA COAST
TODAY AND TONIGHT AND THEN ACROSS NORTHERN MEXICO WEDNESDAY. THIS
STORM WILL BRING RAIN AND SNOW TO MUCH OF THE AREA TODAY THROUGH
WEDNESDAY...WITH SNOW LEVELS DOWN TO 3500 FEET IN SOUTHEAST
CALIFORNIA. AFTER THE STORM MOVES AWAY...GENERALLY DRY WEATHER WITH
A WARMING TREND CAN BE EXPECTED THROUGH THE WEEKEND INTO EARLY NEXT
WEEK.
&&

.SHORT TERM...MAIN FOCUS FOR THIS PACKAGE IS THE UPCOMING STORM
WHICH WAS JUST OFFSHORE OF SAN FRANCISCO AT 3 AM. THE MODELS HAVE
TRENDED FARTHER SOUTHWEST WITH ITS TRACK BY ONE OR TWO HUNDRED
MILES...WHICH IS VERY LITTLE IN THE OVERALL PICTURE OF THE
ATMOSPHERE BUT VERY BIG REGARDING ITS EFFECTS ON OUR AREA. THE CORE
OF COLDEST AIR NOW IS FORECAST TO HUG THE CALIFORNIA COAST OR EVEN
REMAIN OFFSHORE RATHER THAN PASSING OVER THE SAN BERNARDINO COUNTY
DESERTS. THUS...SNOW LEVELS SHOULD REMAIN HIGHER THAN PREVIOUSLY
EXPECTED. THIS TAKES MOST OF THE DESERT FLOOR OUT OF THE SNOW ZONE
AND PUTS THEM IN THE RAIN ZONE. UPGRADED THE WINTER STORM WATCHES
FOR INYO AND SAN BERNARDINO COUNTIES TO WINTER WEATHER ADVISORIES
AND LIMITED THEM TO AREAS ABOVE 4000 FEET...WHICH IS WHERE THE MOST
SIGNIFICANT SNOW SHOULD OCCUR. THANKS TO PSR AND SGX FOR
COORDINATION ON THIS ISSUE. UPGRADED THE CLARK COUNTY MOUNTAINS TO A
WINTER STORM WARNING...BUT CONFIDENCE IN THIS WARNING IS NOT THE
GREATEST BECAUSE IF THE STORM TRACKS ANY FARTHER SOUTHWEST THAN THE
MODELS SHOW THE PRECIP SWATH COULD MISS CLARK COUNTY ENTIRELY. WILL
CONTINUE TO MONITOR. AS THE STORM MOVES INTO NORTHERN SONORA
WEDNESDAY AFTERNOON...LEFTOVER SHOWERS WILL TAPER OFF FROM NORTHWEST
TO SOUTHEAST...LEADING TO A DRY DAY THURSDAY WITH TEMPERATURES
WARMING ALMOST BACK TO NORMAL.

.LONG TERM...MODELS HAVE PRETTY MUCH COME TOGETHER FOR THE EXTENDED.
FRIDAYS WAVE IS DEPICTED BY ALL AS A WEAK ONE SHUNTED NORTH OF OUR
CWA. I HAVE LOWERED POPS MORE...ESPECIALLY IN OUR SOUTH...AND THINK
WHATEVER WILL OCCUR WILL IN THE NORTHERN MOUNTAINS. THIS MAY NEED TO
BE LOWERED MORE IN FUTURE FORECASTS. RIDGING BUILDS IN SATURDAY AND
FOR THE REST OF THE EXTENDED. I RAISED TEMPERATURES A LITTLE TO BE
CLOSER TO GUIDANCE WHICH IS GOING FOR TEMPERATURES SLIGHTLY ABOVE
NORMAL. IT WILL BE A NICE BREAK FROM THE COOL AND WET WE HAVE HAD
RECENTLY.
&&

.AVIATION...FOR MCCARRAN...TOUGH CALL FOR TODAY. THE NEXT STORM
SYSTEM WILL BE TRACKING DOWN THE CALIFORNIA COAST TODAY AND BE
BRINGING IN CEILINGS IN THE 5000-8000 FOOT RANGE THIS MORNING BEFORE
THE RAIN COMES IN. RAIN SHOULD BE IN THE AREA BY ABOUT 16Z AND FOR
THE REST OF THE MORNING AND AFTERNOON. CHANCES FOR RAIN WILL
DECREASE TONIGHT BUT NOT ENTIRELY OUT OF THE AREA UNTIL LATE
WEDNESDAY AFTERNOON. CEILINGS WILL GET DOWN TO AROUND 4000-5000
UNDER THE RAIN. FOR NOW TIMING CONFIDENCE IS LOW AND 12Z TAF
REFLECTS BEST ESTIMATE AT THE TIME IT WAS WRITTEN.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...A LOW PRESSURE SYSTEM IS DROPPING SOUTH ALONG THE
CALIFORNIA COAST THIS MORNING AND INTO THE EVENING BEFORE IT TRACKS
IN THE NORTHERN GULF OF CALIFORNIA ON WEDNESDAY. RAIN AND HIGHER
ELEVATION SNOW WILL BE SPREADING ACROSS CALIFORNIA AND INTO CENTRAL
NEVADA AND NORTHWEST ARIZONA THIS MORNING ON THE EAST AND NORTH SIDE
OF THE LOW. MOUNTAIN AREAS WILL BE OBSCURED WITH THIS SYSTEM AND
HAVE SIGNIFICANT SNOWFALLS WHILE THE VALLEY AREAS BELOW 4500 FEET
WILL BE RAIN. CEILINGS SHOULD BE AOB 5000 FEET OVER MOST OF THE AREA
THROUGH TONIGHT.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...WINTER STORM WARNING FROM 8 PM THIS EVENING TO 10 AM PST
     WEDNESDAY FOR NVZ018-019.
AZ...NONE.
CA...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 4 AM PST
     WEDNESDAY FOR CAZ519>522.
     WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 10 AM PST
     WEDNESDAY FOR CAZ523>526.
&&

MORGAN/JACQUES

HTTP://WEATHER.GOV/LASVEGAS