UPPER LEVEL LOW PRESSURE SYSTEM

FXUS66 KLOX 171611

AFDLOX
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
900 AM PDT MON OCT 17 2005

.SHORT TERM...

AN UPPER LEVEL LOW PRESSURE SYSTEM REMAINS CENTERED AROUND 300 MILES
SOUTHWEST OF LOS ANGELES...AND IS EXPECTED TO REMAIN NEARLY STATIONARY
THROUGH TONIGHT. DURING THIS TIME...THERE WILL BE A MOIST
SOUTHEAST FLOW WHICH WILL CONTINUE TO BRING A THREAT OF SHOWERS AND
THUNDERSTORMS TO THE REGION. CURRENT DOPPLER RADAR SHOWING AN AREA
OF LIGHT TO MODERATE RAIN OVER THE MOUNTAINS OF LOS ANGELES AND
VENTURA COUNTIES...AS WELL AS THE ANTELOPE VALLEY. A BAND OF HEAVIER
SHOWERS AND THUNDERSTORMS IS BEGINNING TO DEVELOP OFF THE COAST
OF SAN DIEGO COUNTY. THIS BAND OF HEAVIER SHOWERS AND POSSIBLE THUNDERSTORMS
IS EXPECTED TO SPREAD NORTHWARD INTO OUR COASTAL WATERS AND ADJACENT
COASTAL AREAS THIS AFTERNOON AND TONIGHT. AS A RESULT...A FLASH FLOOD
WATCH REMAINS IN EFFECT FOR VENTURA AND LOS ANGELES COUNTIES...MAINLY
NEAR THE BURN AREAS. FOR MORE INFORMATION ON THE FLOOD WATCH...PLEASE
REFER TO THE LATEST FLASH FLOOD WATCH PRODUCT (LAXFFALOX).
HIGHEST RAINFALL TOTALS ARE STILL EXPECTED TO BE CONFINED TO AREAS
SOUTH OF POINT CONCEPTION.

WITH THE CLOSE PROXIMITY OF THE UPPER LOW TO SOUTHERN CALIFORNIA...THE
STRONG SOUTHEAST TO EAST FLOW ALOFT HAS GENERATED GUSTY WINDS ACROSS THE
MOUNTAINS LAST NIGHT AND THIS MORNING. WIND ADVISORY STILL IN EFFECT FOR
THE MOUNTAINS OF LOS ANGELES AND VENTURA COUNTIES THROUGH THIS MORNING...FOR
MORE INFORMATION PLEASE REFER TO THE LATEST WIND ADVISORY STATEMENT
(LAXNPWLOX).

LATEST NAM AND GFS MODELS CONTINUE IDEA OF SHIFTING UPPER LOW TO THE
NORTHEAST LATE TONIGHT AND TUESDAY...TRACKING THE UPPER LOW NEAR YUMA
BY 00Z WEDNESDAY. AS THIS OCCURS...THE ATMOSPHERE IS EXPECTED TO
GRADUALLY DRY AND THE THREAT OF SHOWERS AND THUNDERSTORMS IS EXPECTED
TO DIMINISH THROUGH THE DAY TUESDAY. THE THREAT OF SHOWERS IS EXPECTED
TO END ACROSS ALL AREAS BY TUESDAY NIGHT.

*** LONG TERM AND AVIATION FROM PREVIOUS DISCUSSION ***

.LONG TERM...

MEDIUM RANGE MODEL AGREEMENT IS GOOD THROUGH THE PERIOD. AFTER THIS
STORM DEPARTS...LOOK FOR WEAK RIDGING TO BUILD OVER THE AREA BY LATE
IN THE WEEK AND CONTINUE INTO THE WEEKEND. LATE IN THE WEEKEND A
PACIFIC TROUGH APPROACHES...BUT CONDITIONS SHOULD CONTINUE TO BE
FAIR AND DRY THROUGH THE END OF THE PERIOD...WITH SOME MARINE LAYER
CLOUDS AND FOG RETURNING TO OUR COASTS WEDNESDAY...NORTH OF POINT
CONCEPTION...AND THURSDAY FOR THE CALIFORNIA BIGHT.

&&

.AVIATION...

SHOWERS AND THUNDERSTORMS WILL TAPER OFF THIS MORNING. A SECOND
ROUND OF SHOWERS AND THUNDERSTORMS WILL AFFECT THE TAF SITES LATER
THIS AFTERNOON AND LAST INTO THE NIGHT. CIGS AND VIS SHOULD STAY
ABOVE VFR THRESHOLDS THIS MORNING EXCEPT BRIEFLY LOWER UNDER HEAVIER
SHOWERS.

KLAX WILL HAVE EASTERLY WINDS 4 TO 8 KT LASTING INTO THE EARLY
AFTERNOON AND LIGHT VARIABLE WINDS DURING THE AFTERNOON.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...

FLOOD WATCH (SEE LAXFFALOX).
FLOOD ADVISORY (SEE LAXFLSLOX).
WIND ADVISORY (SEE LAXNPWLOX).
SMALL CRAFT ADVISORY (SEE LAXCWFLOX).
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).

&&

PUBLIC...GOMBERG/DANIELSON
AVIATION...RORKE