Wet pattern coming to SoCal

[weatherlover427]

.SYNOPSIS...HIGH PRESSURE ALOFT WILL BRING DRY...WARMER WEATHER MONDAY AND TUESDAY. HOWEVER...UPPER LEVEL MOISTURE ASSOCIATED WITH LOW PRESSURE PASSING TO THE NORTH WILL BRING HIGH CLOUDS MONDAY AND TUESDAY. STRONG LOW PRESSURE ALOFT FROM THE PACIFIC WILL MOST LIKELY MOVE THROUGH LATE WEDNESDAY AND WEDNESDAY NIGHT AND BRING A PERIOD OF RAIN...WITH SNOW IN THE HIGHER MOUNTAINS. AFTER WEAK HIGH PRESSURE MOVES BY LATE IN THE WEEK...ANOTHER SYSTEM COULD AFFECT THE AREA NEXT WEEKEND AND BRING MORE RAIN.

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES.

.SHORT TERM...SWATH OF HIGH CLOUDS OVER THE EASTERN PACIFIC ASSOCIATED WITH SHORTWAVES RIDING OVER THE TOP OF THE UPPER RIDGE OVER THE SW US. THE INCREASE IN HTS AND THKNS WILL BE PARTIALLY OFFSET BY THE CLOUD COVER AND HAS SCALED BACK SLIGHTLY ON THE HIGH TEMPS THE NEXT TWO DAYS. THICKEST CLOUDS WILL BE OVER THE SBD COUNTY MTNS AND THE HIGH DESERTS...CLOSEST TO THE STORM TRACK...WITH LESS HIGH CLOUDS NEAR THE MEXICAN BORDER.

.MEDIUM RANGE...FOCUS SHIFTS TO WEDNESDAY WHERE THE GFS WAS FAIRLY CONSISTENT WITH LAST NIGHTS MODEL RUN TAKING THE TROF AXIS ACROSS SOCAL AROUND 06Z THURSDAY. MAJORITY OF PRECIP WITH THIS SYSTEM IS EXPECTED BETWEEN 21Z WEDNESDAY AND 09Z THURSDAY...WITH POST FRONTAL INSTABILITY SHOWERS LINGERING INTO THURSDAY MORNING. ITS FAST MOVEMENT AND THE INITIALLY DRY LOW LEVELS WILL PRECLUDE THIS FROM BEING A LONG DURATION HEAVY RAIN EVENT. NEVERTHELESS...STRONG DYNAMICS AND STEEP LAPSE AND FAVORABLE OROGRAPHICS WILL LIKELY BRING A PERIOD OF HEAVY RAINS TO THE MOUNTAIN AREAS WEDNESDAY EVENING. CURRENT SPECIAL WEATHER STATEMENT FOR THREAT OF HEAVY RAIN/MUDSLIDES/FLASH FLOODS FOR THIS PERIOD LOOKS ON TARGET.

A BREAK IN THE WEATHER FRIDAY AS A RIDGE BUILDS AHEAD OF THE NEXT PACIFIC TROUGH SLATED TO HIT SOCAL OVER THE WEEKEND FOR WHAT COULD BE A LONGER DURATION RAIN EVENT. SPLIT FLOW DEVELOPS SATURDAY WITH SOUTHERN STREAM MOISTURE REACHING SOCAL FOR MORE RAIN SATURDAY INTO SUNDAY. ON MONDAY...ANOTHER UPSTREAM PACIFIC SHORTWAVE THEN DROPS INTO THE SOUTHERN BRANCH BRINGING PACIFIC MOISTURE AND CHANCES AT MORE RAIN EARLY NEXT WEEK. GFS IS MOST AGGRESSIVE WITH THIS SOLUTION WHILE THE ECMWF IS LESS GUNG-HO. THIS TROUGH IS ONE TO BE CLOSELY MONITORED FOR LONG RANGE MODEL CONSISTENCY.

Could this be related to that Kelvin wave and/or MJO?

[weatherlover427]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO
200 PM PST MON FEB 16 2004

.SYNOPSIS...HIGH PRESSURE OVER THE SOUTHWEST WILL BRING WARM...DRY WEATHER TUESDAY. ON WEDNESDAY A PACIFIC STORM APPROACHING SOUTHERN CALIFORNIA WILL BRING A CHANCE FOR RAIN DURING THE AFTERNOON. MOST OF THE RAIN AND MOUNTAIN SNOW WILL FALL WEDNESDAY NIGHT AS THE STORM MOVES ACROSS THE REGION. WEAK HIGH PRESSURE WILL BUILD THURSDAY BEFORE ANOTHER IN A SERIES OF PACIFIC STORMS BRINGS ANOTHER CHANCE FOR RAIN LATE FRIDAY AND INTO THE WEEKEND.

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES.

12Z NKX SOUNDING SHOWED WARMING OF 5C IN THE LOW LAYERS THE PAST 24 HOURS...AND THIS IS REFLECTED IN THE SURFACE TEMPS TODAY WHERE MOST AREAS ARE SEVERAL DEGREES HIGHER THAN SUNDAY. MID AND HIGH LEVEL CLOUDS KEPT TEMPS LOWER THAN THEY COULD HAVE BEEN THIS AFTERNOON. LESS MID CLOUDS ARE EXPECTED TUESDAY WHICH WILL ADD SEVERAL MORE DEGREES OF WARMING. COUPLED WITH INCREASING HTS AND THKNS...TUESDAY AFTERNOONS HIGH COULD BE 10 TO 15 DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR. ONE CAVEAT...TEMPS NEAR THE COAST WILL BE KEPT DOWN BY THE COOL OCEAN WATERS (57F) AND THE AFTERNOON SEA BREEZE.

ON WEDNESDAY A STRONG PACIFIC STORM WILL BRING INCREASING CLOUDS AND WINDS DURING THE DAY. TIMING TO ONSET OF THE PRECIP IS THE A BIT TRICKY AS THERE IS NOT MUCH MODEL AGREEMENT. CANADIAN MODEL MOST PROGRESSIVE...BRINGING THE SHORTWAVE ACROSS SOCAL WEDNESDAY. THIS SOLUTION IS AT ODDS WITH THE SLOWER GFS AND EVEN SLOWER ETA OUTPUT. BELIEVE THE GLOBAL GFS SOLUTION HAS THE BEST HANDLING ON THE TIMING OF THIS FEATURE SHOWING GREATER CONTINUITY AND BEST QPF OUTPUT.

ALTHOUGH THE RAIN COULD START AS EARLY AS WEDNESDAY AFTERNOON...THE BULK OF THE PRECIP WILL FALL WEDNESDAY EVENING AND THEN END EARLY THURSDAY AS THE TROUGH AXIS MOVE THROUGH. THIS POTENT...FAST MOVING STORM WILL BRING A 3 TO 6 HOUR PERIOD OF MODERATE TO HEAVY RAIN WITH 0.25 TO 0.50 INCHES IN THE COASTAL AND VALLEY AREAS...AND 1.00 TO 1.25 INCHES MOUNTAINS AND FOOTHILLS. BRIEF HEAVY RAINS OF 0.25 INCHES IN 15 MINUTES ARE POSSIBLE WITH THE HEAVIEST DOWNPOURS AND THIS IS CLOSE TO FLASH FLOOD GUIDANCE FOR THE BURN AREAS FOR POSSIBLE MUDSLIDES. WILL CONTINUE TO MONITOR THE STORMS DEVELOPMENT AND CONSIDER POSSIBLE FLASH FLOOD WATCHES IN THE THE BURN AREAS.

INITIALLY THE AIRMASS WILL BE QUITE WARM WITH THE SNOW LEVEL ABOVE 8000 FEET WEDNESDAY AFTERNOON. TEMPS WILL FALL SHARPLY WEDNESDAY NIGHT WITH COLD FRONTAL PASSAGE WITH THE SNOW LEVEL DROPPING TO 4500 FEET.

STORM EXITS THURSDAY FOR A BRIEF RESPITE THURSDAY NIGHT BEFORE A LONG WAVE TROUGH SETS UP OFF THE COAST FRIDAY. THE GFS AND ECMWF IN CLOSER AGREEMENT TODAY WITH THIS BROAD...SLOW MOVING UPPER TROUGH THAT WILL BRING SHOWERS LATE FRIDAY THROUGH THE WEEKEND. MEDIUM TO LONG RANGE MODELS ARE IN REMARKABLE AGREEMENT WITH A SERIES OF SOUTHERN STREAM SHORTWAVES LINED UP OVER THE PACIFIC EXPECTED TO BRING MORE RAIN TO SOUTHERN CALIFORNIA NEXT WEEK.

COORDINATED TIMING OF PRECIP AND QPF WITH OXNARD.

Definitely looking much more like a wet pattern now.

[weatherlover427]

FCST FCST FCST FCST FCST FCST FCST
TODAY THU FRI SAT SUN MON TUE
FEB 18 FEB 19 FEB 20 FEB 21 FEB 22 FEB 23 FEB 24

...ORANGE COUNTY COASTAL AREAS...
ANAHEIM
RAIN PTCLDY PTCLDY MOCLDY RAIN MOCLDY MOCLDY
/66 46/67 47/64 47/63 48/61 47/62 47/63
POP 70 POP 0 POP 20 POP 30 POP 50 POP 40 POP 40

NEWPORT BEACH
RAIN PTCLDY PTCLDY MOCLDY RAIN MOCLDY MOCLDY
/61 49/62 49/60 50/59 51/58 51/58 50/59
POP 70 POP 0 POP 20 POP 30 POP 60 POP 40 POP 40

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
300 AM PST WED FEB 18 2004

.SHORT TERM...THINGS ARE ALREADY GETTING INTERESTING EARLY THIS MORNING ACROSS THE FORECAST AREA. DOPPLER RADAR/SATELLITE SHOW FRONT SLOWING MOVING TOWARDS CENTRAL COAST...WITH RAIN AND ISOLATED THUNDERSTORMS. ISSUED SEVERE THUNDERSTORM WARNING EARLIER FOR STORM ACROSS NORTHWEST SLO COUNTY. LOOKING AT RADAR/SATELLITE...BELIEVE THE ETA IS OUT TO LUNCH...SO WILL GO WITH GFS SOLUTION FOR THE FORECAST. TO THAT END...EXPECT FRONT TO MOVE ACROSS CENTRAL COAST THIS MORNING AND ACROSS VTU/LAX COUNTIES THIS AFTERNOON. BY LATE THIS EVENING... FRONT IS PROGGED TO BE EAST OF THE AREA...WITH SOME LINGERING SHOWERS ON THE NORTH SLOPES OVERNIGHT AND EARLY THURSDAY MORNING. EXPECT DECENT RAIN TOTALS...GENERALLY 0.25 TO 1.00 INCH ACROSS COASTAL AREAS WITH UP TO 1.50 INCHES AT HIGHER ELEVATIONS...WITH THE HEAVIEST AMOUNTS NORTH OF POINT CONCEPTION. MODELS INDICATE DECENT INSTABITLY TODAY...SO WILL KEEP MENTION OF THUNDER FOR ALL AREAS. GIVEN EXPECTED RAINFALL AND POTENTIAL FOR HEAVY SHOWERS/THUNDERSTORMS...WILL ISSUE FLASH FLOOD WATCH FOR BURN AREAS IN VTU/LAX COUNTIES. AS FOR SNOW... EXPECT SNOW LEVEL TO REMAIN ABOVE 8000 FEET THIS MORNING...THEN DROP TO AROUND 6000 FEET THIS AFTERNOON AND EVENING. WITH SUCH HIGH SNOW LEVELS...DO NOT ANTICIPATE ANY NEED FOR WINTER WEATHER PRODUCTS AT THIS TIME.

ON THURSDAY...PARTLY CLOUDY AND DRY CONDITIONS WILL PREVAIL. ON FRIDAY/FRIDAY NIGHT...ANOTHER SYSTEM IS PROGGED TO MOVE ACROSS THE AREA. MOISTURE/DYNAMICS ARE LIMITED WITH THIS SYSTEM...SO WILL GO WITH ONLY SLIGHT CHANCE POPS AT THIS TIME.

.LONG TERM...EXTENDED MODELS INDICATE CONTINUED UNSETTLED WEATHER PATTERN FOR THE AREA. MODELS DIFFER IN THE DETAILS...SO FORECAST CONFIDENCE IS NOT HIGH FOR ANY DAY. WILL INDICATE PARTLY/MOSTLY CLOUDY SKIES THROUGH THE EXTENDED PERIOD...WITH A CHANCE OF RAIN. PRECIP FORECAST CAN BE FINE TUNED WITH FUTURE MODEL RUNS.

Portland-like weather alert! :o

[JCT777]

Definitely seems like a wet time ahead for California. LC, who usually makes a bigger deal about a small storm in the east than a major storm in the west, went out of his way to talk about how California and the entire SW area of the US will be getting pounded with precip over the next 10 days.

[Aslkahuna]

SW US as Tucson has our precip chances at no better than 20% through the next week plus.

Steve

[weatherlover427]

We've received a teeny bit over 1/4" here today and that will likely end up being our final total for this storm. I eagerly await the next several.

[weatherlover427]

.FRIDAY...MOSTLY CLOUDY. HIGHS 55 TO 62. LIGHT WINDS.
.FRIDAY NIGHT...MOSTLY CLOUDY WITH A 30 PERCENT CHANCE OF SHOWERS. LOWS 38 TO 43. LIGHT WINDS...BECOMING SOUTHWEST 15 MPH AFTER MIDNIGHT.
.SATURDAY...MOSTLY CLOUDY WITH A 40 PERCENT CHANCE OF SHOWERS. HIGHS 53 TO 60. SOUTHWEST WINDS AROUND 15 MPH.
.SATURDAY NIGHT...MOSTLY CLOUDY. CHANCE OF SHOWERS. LOWS 39 TO 47.
.SUNDAY...RAIN LIKELY. HIGHS 51 TO 60.
.SUNDAY NIGHT...CHANCE OF RAIN. LOWS 39 TO 47.
.MONDAY...MOSTLY CLOUDY. CHANCE OF RAIN. HIGHS 51 TO 59.
.MONDAY NIGHT...MOSTLY CLOUDY. CHANCE OF RAIN. LOWS 38 TO 44.
.TUESDAY...CHANCE OF RAIN. HIGHS 51 TO 59.
.TUESDAY NIGHT...CHANCE OF RAIN. BREEZY. LOWS 38 TO 45.
.WEDNESDAY...CHANCE OF RAIN. HIGHS 54 TO 62.

Great forecast ... if you like rain that is.

[btangy]

Received about .75 inches today here at UCLA because got more of an upslope flow. Some brief periods of heavy rain, but otherwise just light to moderate in intensity since about 1pm. Tomorrow the models are showing more in the way of dynamics, but as to where the bulk of the precip will fall is questionable still. These tiny vorticity centers pinwheeling around this huge trough in the west are very hard to resolve in both the GFS and ETA. Even on satellite, they are very hard to pick out. Since the jet is so far south, I'm inclined to say the precip will be focussed further south into Orange and SD counties, but the ETA seems to like the idea of hooking a surface low near Catalina. Seems kind of suspect, but we'll see tomorrow.

After that, Wednesday is becoming quite worrisome as the GFS has consistently shown a 2-3 inch storm slamming most of SoCal. Tomorrow, we'll see what the ETA has to say about precip for the next storm. Major mudslides and flooding a definite possibility.