High Wind in California, January 8, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
250 PM PST SAT JAN 8 2005

.SYNOPSIS...A STRONG PACIFIC STORM ANCHORED ALONG THE OREGON COAST
WILL CONTINUED TO BRING A VERY MOIST SOUTHWEST FLOW ACROSS THE
DESERT SOUTHWEST. THIS WILL RESULT IN A CHANCE OF RAIN AND
SNOW...POSSIBLY HEAVY AT TIMES...ESPECIALLY OVER THE MOUNTAINS
THROUGH THE WEEKEND.
&&

.SHORT TERM...STRONG SOUTHWEST FLOW ACROSS THE CWA ALONG THE BOTTOM
OF UPPER LOW ENTRENCHED OVER THE PACNW COAST. FLOW TODAY HAS BEEN
LACKING DYNAMICS RESULTING IN VERY LITTLE RAIN/SNOW OVER THE VALLEY
LOCATIONS...WHILE OROGRAPHICS HAVE KEPT SNOW GOING ACROSS THE
SOUTHERN SIERRA/SOUTHERN NEVADA MOUNTAINS. GFS/ETA CONTINUE TO BE IN
GOOD AGREEMENT ON A SYNOPTIC SCALE...HOWEVER DETAILS REMAIN
DIVERGENT. GFS CONTINUING TO KEEP SOUTHWEST FLOW VERY MOIST INTO
MONDAY WITH CONSIDERABLE QPF ACROSS THE SOUTHERN PORTION OF THE
DISTRICT...ESPECIALLY SUNDAY AFTERNOON AND INTO MONDAY WITH FAIRLY
DRY CONDITIONS ACROSS THE SOUTHERN SIERRA. ETA ON THE OTHER HAND
MUCH DRIER SOUTH WITH MAIN MOISTURE INTO THE SOUTHERN SIERRA.
EXAMPLE BEING POP FORECAST FOR LAS SUNDAY MORNING...18Z GFS HAS 72
PCT AND ETA HAS 8 PCT. DUE TO THE DIFFERENCE IN THE MODELS...
FORECAST CONFIDENCE IS FAIRLY LOW AT THIS POINT. SHORT WAVE
CURRENTLY OFF THE SOUTHERN CA COAST TO MOVE INLAND OVERNIGHT...BUT
BOTH ETA/GFS SHOW VERY FLAT DYNAMICS ACROSS THE SOUTHERN PORTION OF
THE CWA TONIGHT...EXCEPTION IS WEAK JET DYNAMICS AND OROGRAPHICS.
MEANWHILE MOIST FLOW REMAINING ACROSS THE SIERRA. THUS WILL KEEP CHC
POPS OVER THE VALLEY LOCATIONS WITH LIKELY ACROSS THE MOUNTAINS AND
CONTINUE CURRENT WS WARNINGS. BY SUNDAY/MONDAY DIFFICULT TO PICK OUT
SHORT WAVES...AND FLAT DYNAMICS CONTINUE SO HAVE CONTINUED
BROADBRUSH POPS. DO NOT BELIEVE THAT WSW FOR SRN MTNS WILL NEED TO
BE EXTENDED BEYOND SUNDAY MORNING...BUT MAY NEED TO EXTENDED
SOUTHERN SIERRA INTO MONDAY OR TUESDAY...ESPECIALLY IF ETA BECOMES
MODEL OF CHOICE IN LATER RUNS. BY MONDAY NIGHT/EARLY TUESDAY...
UPPER LOW OVER PACNW PROGGED TO FINALLY KICK IN ACROSS NORTHERN
CALIFORNIA...KEEPING UNSETTLED WEATHER GOING AT LEAST THROUGH THEN.
TEMPS LAST NIGHT WARMED RAPIDLY AS WINDS FINALLY KICK IN ACROSS THE
CWA. TODAYS AFTERNOON TEMPS WARMED 15-20 DEGREES ABOVE THOSE BEING
REPORTED ON FRIDAY AND SINCE LITTLE COOLING EXPECTED UNDER SOUTHWEST
FLOW...WILL TREND FAIRLY WARM DAYTIME HIGHS INTO MONDAY WHILE
OVERNIGHT LOWS TO MODERATE CONSIDERABLY TOO. SURFACE GRADIENTS HAVE
WEAKENED CONSIDERABLY TODAY AND ALTHOUGH SOME GUSTY WINDS STILL
OCCURRING...SHOULD NOT BE A FACTOR...WITH EXCEPTION OF MOUNTAIN
LOCATIONS NEXT COUPLE OF DAYS.

.LONG TERM...GFS/EURO IN FAIR AGREEMENT WITH THE MAIN LOW PRESSURE
SYSTEM...CURRENTLY OFF THE OREGON COAST...MOVING INTO NORTHERN
CALIFORNIA VERY EARLY ON TUESDAY. MODELS THEN QUICKLY SWEEP THE
SYSTEM INTO UTAH BY 00Z. THIS WILL SPREAD ONE LAST ROUND OF PRECIP
OUT AHEAD OF IT ON TUESDAY...BEFORE THE PATTERN FINALLY CHANGES AND
WE START TO DRY OUT. UNLIKE THE PREVIOUS SEVERAL SYSTEMS...THIS ONE
WILL ALSO BE ACCOMPANIED BY FAIRLY DECENT COLD FRONT WHICH WILL PASS
THROUGH DURING THE DAY BRINGING WITH IT GUSTY WINDS. 12Z ETA TIMING
WAS IN GOOD AGREEMENT WITH OTHER MODELS...HOWEVER 18Z ETA RUN IS
CONSIDERABLY SLOWER WITH THE PROGRESSION OF THIS SYSTEM. WILL STAY
WITH GFS/EURO TIMING FOR NOW...BUT WILL WATCH THE ETA SOLUTION SINCE
THE UKMET IS ALSO SLOWER. SNOW LEVELS WILL DROP VERY LOW ON TUESDAY
BEHIND THE FRONT...TRICKY PART WILL BE IF THERE IS ENOUGH MOISTURE
LEFT FOR SHOWERS TO DEVELOP. SNOW LEVELS COULD BE LOW ENOUGH TO
AFFECT KINGMAN AND THE HIGHEST PARTS OF LAS VEGAS. SYSTEM MOVES OUT
BY TUESDAY NIGHT THEN A MORE SIMPLIFIED PATTERN SETS UP FOR THE REST
OF THE WEEK. RIDGE BUILDING OVER THE PACIFIC AND EXTENDING INTO THE
SOUTHERN GULF OF AK SHOULD KEEP STORM SYSTEMS TO OUR NORTH AS WE
REMAIN UNDER NORTHWEST FLOW THROUGH THURSDAY. RIDGE THEN FORECAST BY
THE EURO TO MOVE OVERHEAD FRIDAY AND INTO SATURDAY. PAST FEW GFS
RUNS HAVE BROUGHT A LOW PRESSURE SYSTEM THROUGH THE RIDGE ON
SAT...BUT TIMING IS SLOWER AND SYSTEM IS WEAKER WITH EACH RUN. WILL
KEEP THE EXTENDED FROM WEDNESDAY ON DRY FOR NOW. TEMPERATURES SHOULD
BE FAIRLY CLOSE TO NORMAL AFTER WE BEGIN TO RECOVER THURSDAY.
&&

.AVIATION...VERY HIGH LEVEL OF UNCERTAINTY WITH KLAS TAF IN REGARDS
TO PRECIP TIMING. VERY MOIST FLOW REMAINS OVER THE REGION WITH ONLY
SCATTERED SHOWERS TO DEVELOP NOW AND THEN OVER THE NEXT 24 HOURS.
BEST CHANCE LOOKS LIKE IT WILL BE TOMORROW MORNING THROUGH AFTERNOON
AS A LARGE PLUME OF MOISTURE MOVES IN JUST SOUTH OF THE LAS VEGAS
VALLEY.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
.NV...WINTER STORM WARNING THROUGH 10 AM SUNDAY ABOVE 6000 FEET
      FOR ZONES 18 AND 19.
.AZ...NONE.
.CA...WINTER STORM WARNING THROUGH 4 PM SUNDAY FOR ZONE 26 ABOVE
      5000 FEET.
&&

JENSEN/DAVIS