Area Forecast Discussion
Issued by NWS Los Angeles, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KLOX 261845
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1040 AM PST MON JAN 26 2015

...NEW AVIATION/MARINE DISCUSSIONS...

.SYNOPSIS...
A COUPLE OF LOW PRESSURE SYSTEMS WILL IMPACT THE AREA THIS WEEK. THE
FIRST WILL LIKELY BRING SHOWERS THROUGH EARLY TUESDAY. THE NEXT
COULD BRING A SMALL CHANCE OF RAIN THURSDAY OR FRIDAY. TEMPERATURES
WILL REMAIN NEXT NORMAL THROUGH THE WEEK.

&&

.SHORT TERM (TODAY-WED)...
THE LOW PRESSURE SYSTEM THAT WILL IMPACT US THROUGH TUESDAY REMAINS
450 MILES SOUTHWEST OF LOS ANGELES. SOUTHEAST FLOW HAS SETTLED INTO
THE AREA...BRINGING A WARM AIRMASS UP FROM THE SOUTH. WHILE MAXIMUM
TEMPERATES WILL BE MUCH LOWER THAN YESTERDAY...THEY WILL BE A FEW
DEGREES WARMER THAN PREVIOUSLY EXPECTED DUE TO THE LOCALIZED
OFFSHORE FLOW AND WARM START TO THE MORNING. UPDATED FORECAST
ACCORDINGLY. WHILE NO MEASURABLE RAIN IS EXPECTED THIS
MORNING...ADDED A SLIGHT CHANCE TO LOS ANGELES COUNTIES WITH A FEW
REPORTS OF LIGHT BIG DROP RAIN. RAIN CHANCES FOR LATE THIS AFTERNOON
AND NIGHT LOOK UNCHANGED FROM PREVIOUS FORECAST. WISH WE COULD BE
MORE DEFINITIVE WITH THE POPS...BUT UNCERTAINTY REMAINS AS TO THE
COVERAGE OF MEASURABLE RAIN. THIS IS DUE TO THE FLOW LOOKING MORE
EASTERLY THAN SOUTHEASTERLY WHICH WOULD PRODUCE A DRYING EFFECT AT
LOWER LEVELS. REGARDLESS...ANY RAINFALL STILL LOOKS LIGHT. THE
MOISTURE ALSO LOOKS TO EXIT THE AREA A LITTLE QUICKER...SO TUESDAY
MORNING POPS MAY NEED TO BE TRIMMED BACK WITH THE AFTERNOON PACKAGE.

***FROM PREVIOUS DISCUSSION***

563 DM UPPER LOW 400 MILES SOUTH WEST OF L.A. THIS LOW WILL SLOWLY
MAKE ITS WAY TO THE NNE AND WILL BE OVER PT CONCEPTION AROUND DAWN
TUESDAY. AS THIS LOW MOVES TOWARDS THE REGION IT WILL ENTRAIN A
LARGE MASS OF MOISTURE OVER SE CA AND AZ AND ADVECT THIS MOISTURE
INTO SRN CA. THIS FLOW TRAJECTORY WILL ACTUALLY FAVOR RAIN CHANCES
FOR THE L.A. MTNS AND THE ANTELOPE VLY. THIS MORNING WILL BE MOSTLY
CLOUDY AND THERE WILL BE A BIG DROP SPRINKLE OR TWO HERE AND THERE
AS SOME PRECIP FALLS FROM THE MID LEVEL DECKS BUT NOTHING OF NOTE OR
OVER A HUNDREDTH OF AN INCH. THERE WILL BE ENOUGH MOISTURE OVER THE
AREA MIXED WITH A LITTLE PVA TO BRING A CHC OF LIGHT RAIN SHOWERS TO
MOST OF L.A. COUNTY AND A SLIGHT CHC TO VTA COUNTY. THE BEST CHC OF
RAIN WILL BE THIS EVENING. THE UPPER LOW WILL BE 100 MILES SOUTHWEST
OF PT CONCEPTION MAXIMUM MOISTURE WILL BE OVER THE AREA AND A VORT
MAX WILL ROTATE OVER THE FORECAST AREA FROM THE SOUTH TO THE NORTH.
RAIN WILL BE LIKELY FOR L.A. COUNTY AND MOST OF THE MTNS. DUE TO THE
SE TO NW MOVEMENT OF THE VORT MAX THERE WILL ONLY BE CHC OF RAIN
OVER THE WATERS AND THE VLYS AND COASTAL SECTIONS OF VTA COUNTY.
THERE WILL ONLY BE A SLIGHT CHC OF RAIN OVER THE CENTRAL COAST. THE
CHC OF PRECIP WILL DIMINISH AFTER MIDNIGHT AS THE VORT LOBE MOVES
OFF. BY TUESDAY MORNING THE CHC OF RAIN WILL BE CONFINED TO AREAS
NORTH OF PT CONCEPTION...ALL OF THE MTNS AND THE ANTELOPE VLY. BY
TUESDAY AFTERNOON THERE WILL ONLY BE A SLIGHT CHC OF SHOWERS NEAR
THE KERN COUNTY BORDER. SNOW LEVELS WILL BE RATHER HIGH...AROUND
7000 FEET. THE SKI RESORTS COULD SEE AN INCH OR TWO OF NEW SNOW.

RAINFALL AMOUNTS WILL LIKELY BE THE HIGHEST IN THE ANTELOPE VALLEY
AND THE NORTH FACING SLOPES OF THE SAN GABRIEL MOUNTAINS...WHERE
0.25-0.50" OF RAIN ARE POSSIBLE. AREAS WEST OF THE MOUNTAINS WILL
GENERALLY RECEIVE 0.10-0.25" OR LESS...BUT AMOUNTS WILL BE HIGHLY
VARIABLE. RAINFALL RATES SHOULD REMAIN BELOW ABOUT 0.15" PER HOUR.

WHILE THUNDER IS NOT MENTIONED IN THE FORECAST THE CHC OF A TSTM IS
NOT ZERO. THE AREA NEAR THE LOW CENTER WILL NEED MONITORING.

A LITTLE POP UP RIDGE (AHEAD OF ANOTHER UPPER LOW TO THE SW) IS
SLATED FOR WEDNESDAY. SKIES WILL TURN PARTLY CLOUDY. RISING HGTS AND
WEAK OFFSHORE FLOW WILL ALLOW FOR NICE BUMP UP IN TEMPS.

.LONG TERM (THU-SUN)...
ANOTHER UPPER LOW TO OUR SW PUSHES THE RIDGE OUT AS IT MOVES TOWARDS
SRN CA. THIS LOW IS MUCH WEAKER THAN TODAYS AND WILL LIKELY OPEN UP
INTO A TROF AS IT MOVES OVERHEAD. ONLY THE EC SEES THIS TROF
PRODUCING ANY RAINFALL AND EVEN THEN JUST OVER THE L.A./VTA MTNS AND
THE AV. DURING THIS TIME SKIES WILL BE PARTLY OR MOSTLY CLOUDY AND
MAX TEMPS WILL BE PRETTY CLOSE TO NORMAL PERHAPS A DEGREE OR TWO
WARMER DUE TO THE OFFSHORE FLOW TO THE LOW OFF THE COAST.

BOTH THE EC AND THE GFS AGREE THAT ANOTHER RIDGE IS ON TAP FOR NEXT
WEEKEND. SKIES SHOULD CLEAR AND MAX TEMPS WILL RISE SEVERAL DEGREES
ABOVE NORMALS WITH THE HIGHER HEIGHTS AND WEAK OFFSHORE FLOW.

&&

.AVIATION...26/1800Z.

AT 0920Z AT KLAX... THE INVERSION EXTENDS FROM THE SURFACE UP TO
1200 FEET WITH A TEMPERATURE OF 24 DEGREES C AT THE TOP.

MODERATE CONFIDENCE IN THE 18Z TAFS. VFR CONDITIONS ARE EXPECTED FOR
THE NEXT 24 HOURS IN SPITE OF A THREAT OF LIGHT RAIN AND OVERCAST
SKIES. THERE IS A 30 PERCENT CHANCE OF MVFR CEILINGS OR VISIBILITY
RESTRICTIONS JUST ABOUT ANYWHERE.

KLAX...MODERATE CONFIDENCE IN THE 18Z FORECAST. THERE IS A 30
PERCENT CHANCE OF MVFR CEILINGS OR VISIBILITY RESTRICTIONS.

KBUR...MODERATE CONFIDENCE IN THE 18Z FORECAST. THERE IS A 30
PERCENT CHANCE OF MVFR CEILINGS OR VISIBILITY RESTRICTIONS.

&&

.MARINE...26/900 AM...

AN AREA OF LOW PRESSURE WILL MOVE NORTH OVER THE REGION TODAY...
BRINGING A CHANCE OF PRECIPITATION AND SHIFTING THE WINDS TO THE
SOUTHEAST. WINDS ARE EXPECTED TO REMAIN BELOW 25 KT. NORTH WINDS
WILL RETURN ON WEDNESDAY.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).

&&
$$

PUBLIC...KITTELL/RORKE
AVIATION...SWEET
MARINE...SWEET
SYNOPSIS...SETO

WWW.WEATHER.GOV/LOSANGELES








USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.