000 FXUS66 KLOX 190444 AFDLOX SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 944 PM PDT TUE JUN 18 2013 .SYNOPSIS... A NORTHERLY PRESSURE DIFFERENCE ACROSS THE STATE WILL CREATE GUSTY WINDS ACROSS PORTION OF SOUTHWEST CALIFORNIA THROUGH WEDNESDAY. THE TEMPERATURES SHOULD BE ABOUT NORMAL INTO NEXT WEEK AS THE SOUTHERN PORTION OF A LARGE LOW SYSTEM WILL LINGER OVER THE REGION. THE CENTER OF THE LOW WILL SLOWLY MOVE NORTHEAST OVER THE WEEKEND FOR AN INCREASE IN THE NIGHT TO MORNING MARINE LAYER EARLY NEXT WEEK. && .UPDATE... KSBA-KSMX SURFACE GRADIENTS HOVER NEAR -6 MB THIS EVENING. VERIFICATION OF THE HIGH WIND WARNING HAS ALREADY OCCURRED WITH GAVIOTA SENSORS RECORDING GUSTS UP TO 61 MPH AND SUSTAINED WINDS GREATER THAN 40 MPH. THE LAS FLORES CANYON SENSOR ALSO HAVE RECORDED SUSTAINED WINDS GREATER THAN 40 MPH. A WIND ADVISORY WAS ALSO ADDED FOR THE VENTURA COUNTY MOUNTAINS...AND THE SANTA CLARITA AND SAN FERNANDO VALLEY. NAM-WRF AND LOCAL 4-KM WRF SOLUTIONS CONTINUE TO EXPAND THE NORTHERLY WIND PUSH HINTED AT EARLIER IN 12Z AND 18Z LOCAL 4-KM WRF SOLUTIONS. WITH NAM-WRF AND LOCAL 4-KM SOLUTION PERFORMING WELL WITH THE WIND THE PACKAGE WAS TRENDED THIS DIRECTION. && .PREV DISCUSSION... SHORT TERM...ADVISORY THRESHOLD WINDS WILL LIKELY RETURN AGAIN WEDNESDAY EVENING BUT SLIGHTLY WEAKER THAN TONIGHT AS THE THERMAL TROUGH OVER THE BIGHT BEGINS TO SURGE NORTH AND AIR MODIFIES ALONG THE CENTRAL COAST. GUIDANCE WAS CONSISTENT WITH PREVIOUS RUNS AND A WARMING TREND IS LIKELY AT THE COAST AND COOLING TREND INLAND WEDNESDAY AS THE TROUGH GRADUALLY SHIFTS OVER INTERIOR CALIFORNIA. A WARMING TREND IS LIKELY OVER THE ENTIRE AREA THURSDAY THOUGH TEMPERATURES WILL REMAIN A FEW DEGREES BELOW NORMAL. SLIGHT TEMPERATURES CHANGES ARE EXPECTED FRIDAY...THE TREND WILL REVERSE AND COOL AT THE COAST AND WARM INLAND BY A COUPLE OF DEGREES. LONG TERM...A SURFACE RIDGE OF HIGH PRESSURE IS EXPECTED TO WEAKEN OVER THE EASTERN PACIFIC MONDAY THROUGH TUESDAY. UNTIL THEN A MODERATE TO STRONG ONSHORE PRESSURE GRADIENT WILL CONTINUE NEAR SHORE AND CAUSE AN UNORGANIZED LOW LEVEL CLOUD FIELD WITHIN THE MARINE LAYER. THE BULK OF THE CLOUDINESS MAY OCCUR OVER THE LOS ANGELES BASIN DURING THE NIGHT AND MORNING PERIODS AND OVER PORTION ALONG THE CENTRAL COAST. AS THE RIDGE WEAKENS THE ONSHORE GRADIENT WILL BECOME WEAK TO MODERATE AND LOW LEVEL CLOUDINESS MAY BECOME ORGANIZED. LITTLE CHANGES ARE EXPECTED IN TEMPERATURES WITH SLIGHTLY BELOW SEASONAL NORMALS AT THE COAST AND SLIGHTLY ABOVE NORMAL INLAND ARE LIKELY THROUGH THE PERIOD. && .FIRE WEATHER... INCREASING NORTHWEST TO NORTH FLOW WILL DEVELOP ACROSS THE SANTA BARBARA COUNTY MOUNTAINS AND SOUTH COAST...AS WELL AS THE INTERSTATE 5 CORRIDOR AND ANTELOPE VALLEY. GUSTY SUNDOWNER WINDS WILL AFFECT THE SANTA BARBARA COUNTY MOUNTAINS AND SOUTH COAST...STRONGEST DURING THE LATE AFTERNOON AND NIGHTTIME HOURS. WIND GUSTS BETWEEN 35 AND 45 MPH WILL BE COMMON WITH ISOLATED GUSTS TO 50 MPH. HUMIDITIES ARE GENERALLY EXPECTED TO REMAIN ABOVE 20 PERCENT WITH TONIGHT'S SUNDOWNER WIND EVENT. GUSTY NORTHWEST WINDS WILL ALSO IMPACT THE ANTELOPE VALLEY AS WELL AS THE MOUNTAINS OF LOS ANGELES AND VENTURA COUNTIES...ESPECIALLY NEAR THE INTERSTATE 5 CORRIDOR. THESE AREAS WILL GENERALLY SEE GUSTS IN THE 35 TO 45 MPH RANGE WITH ISOLATED GUSTS OVER 50 MPH NEAR WHITAKER PEAK. ON WEDNESDAY AND EARLY THURSDAY...A DRIER AIR MASS IS FORECASTED TO SURGE INTO INLAND PORTIONS OF THE FORECAST AREA. DURING THIS TIME...THERE WILL LIKELY BE A PROLONGED PERIOD OF HUMIDITIES IN THE TEENS AND SINGLE DIGITS ACROSS THE MOUNTAINS. THESE VERY LOW HUMIDITIES COUPLED WITH THE CONTINUED GUSTY NORTH WINDS AND VERY DRY FUELS WILL LIKELY BRING A PERIOD OF CRITICAL FIRE WEATHER CONDITIONS IN THE MOUNTAINS. AS A RESULT...A RED FLAG WARNING IS IN EFFECT FOR THE MOUNTAINS OF LOS ANGELES...VENTURA...AND SANTA BARBARA COUNTIES...INCLUDING THE FOOTHILLS OF THE SANTA YNEZ RANGE. THIS WARNING IS VALID WEDNESDAY MORNING THROUGH THURSDAY MORNING. BRIEF CRITICAL FIRE WEATHER CONDITIONS ARE ALSO EXPECTED ACROSS THE SANTA BARBARA SOUTH COAST AND WESTERN PORTIONS OF THE ANTELOPE VALLEY...BUT DURATIONS DO NOT APPEAR TO BE SUFFICIENTLY LONG FOR RED FLAG WARNINGS AT THIS TIME. && .AVIATION...19/0500Z. VFR CONDITIONS WILL PERSIST AT MOST TERMINALS EXCEPT FOR IFR TO MVFR CONDITIONS LIKELY AT CENTRAL COAST AND LOS ANGELES COUNTY COASTAL TERMINALS BETWEEN 10Z AND 16Z. VFR CONDITIONS SHOULD REDEVELOP BETWEEN 15Z AND 16Z. KLAX...VFR CONDITIONS WILL PERSIST THROUGH AT LEAST 10Z...THEN THERE IS A 70 PERCENT CHANCE OF IFR TO MVFR CONDITIONS THROUGH 16Z. THERE IS A 30 PERCENT CHANCE OF KBUR...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD. && .LOX WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING (SEE LAXRFWLOX). HIGH WIND WARNING (SEE LAXNPWLOX). GALE WARNING (SEE LAXMWWLOX). WIND ADVISORY (SEE LAXNPWLOX). SMALL CRAFT ADVISORY (SEE LAXMWWLOX). HIGH RIP CURRENT RISK (SEE LAXSRFLOX). && $$ PUBLIC...HALL AVIATION...HALL FIRE WEATHER...GOMBERG SYNOPSIS...SETO WWW.WEATHER.GOV/LOSANGELES