AFDLOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 1006 PM PDT THU JUN 20 2024 .SYNOPSIS...20/134 PM. TEMPERATURES WILL TREND UPWARDS EACH DAY INTO THE WEEKEND, AS HIGH PRESSURE BUILDS ALOFT. ABOVE NORMAL TEMPERATURES EXPECTED FRIDAY INTO EARLY NEXT WEEK, ESPECIALLY FOR AREAS AWAY FROM THE COASTS. DANGEROUSLY HOT CONDITIONS ARE POSSIBLE THIS WEEKEND, ESPECIALLY FOR THE MOUNTAIN AREAS AND ANTELOPE VALLEY. THERE IS A SLIGHT CHANGE OF RAIN SHOWERS SATURDAY THROUGH TUESDAY. && .SHORT TERM (TNT-SUN)...20/1003 PM. CLOUDS ARE SLOWER TO MOVE INTO AREAS SOUTH OF POINT CONCEPTION THIS EVENING BUT THE LOW CLOUD FIELD IS WELL ENTRENCHED ALONG THE CENTRAL COAST. CLOUDS ARE MAKING A DECENT PUSH INTO THE CENTRAL COAST AND SANTA YNEZ VALLEY. THE LATEST UPDATE ENCAPSULATES CLOUD COVER A LITTLE BETTER, EXPANDING CLOUDS INTO THE SANTA YNEZ VALLEY AND SCALING BACK COVERAGE ALONG THE VENTURA COUNTY COAST. THE TIMING ALONG THE LOS ANGELES COUNTY COAST WAS DELAYED A BIT, BUT THERE IS A 30 PERCENT CHANCE OF NO LOW CLOUD COVERAGE FOR LOS ANGELES COUNTY COASTAL AREAS. WITH LESS LOW CLOUD COVERAGE AND HIGH PRESSURE ALOFT BUILDING IN MUCH QUICKER, TEMPERATURES WERE WARMED A BIT MORE FOR FRIDAY, MOST SIGNIFICANTLY ACROSS THE VALLEY AREAS AND INTO THE MOUNTAINS. 950 MB TEMPERATURES RESPOND JUMPING BY ABOUT 3-7 DEGREES ACROSS THE AREA ON FRIDAY, CLOSER TO WHERE THE THERMAL TROUGH SETS UP ACROSS THE INLAND AREAS. 950 MB TEMPERATURES APPROACH 33 DEGREES CELSIUS AT KPRB, A VALUE INDICATIVE OF 100 DEGREE TEMPERATURES FOR DAYTIME HIGHS. A WARMING TREND WILL CONTINUE THROUGH SATURDAY, POTENTIALLY REACHING DANGEROUSLY HOT LEVELS ACROSS THE INTERIOR VALLEYS, SUCH AS THE ANTELOPE VALLEY, AND INTO THE MOUNTAINS. A MARGINAL WIND ADVISORY WAS ADDED FOR SOUTHWESTERN SANTA BARBARA COUNTY THROUGH LATE TONIGHT AS SURFACE PRESSURE GRADIENTS TIGHTENED A LITTLE MORE THAN ADVERTISED. KSBA-KSMX SURFACE PRESSURE GRADIENTS HAVE TIGHTENED TO -4.1 MB CURRENTLY, 0.7 MB TIGHTER THAN THIS TIME LAST NIGHT. WIND GUSTS TO BETWEEN 45 AND 50 MPH HAVE BEEN OBSERVED ALONG THE SOUTHWESTERN COAST AND THE WESTERN SANTA YNEZ RANGE. NO FURTHER UPDATES ARE PLANNED AT THIS TIME. ***FROM PREVIOUS DISCUSSION*** ONSHORE FLOW REMAINS IN PLACE ACROSS THE AREA EARLY THIS EVENING AS WEAK TROUGHING ALOFT SITS OVER THE STATE. LOW CLOUDS AND FOG HUG THE COAST NEAR POINT CONCEPTION AND POISING TO MAKE A RETURN BACK INTO THE CENTRAL COAST THIS EVENING. THE LATEST AMDAR SOUNDINGS FROM KLAX INDICATE THE MARINE LAYER DEPTH TO BE AROUND 1000 FEET DEEP CURRENTLY, WHICH AGREES WELL WITH NAM BUFR TIME HEIGHT SECTIONS. WITH THE DEPTH OF THE MARINE LAYER NEAR 1000 FEET DEEP ACROSS THE AREA, THERE IS A CHANCE THAT LOW CLOUDS COULD BE A LITTLE MORE EXTENSIVE AND MAKE THEIR WAY BACK INTO SANTA YNEZ VALLEY VERY LATE. SOUTH OF POINT CONCEPTION, CLOUDS AT BEST SHOULD REMAIN CONFINED TO COAST AND POSSIBLY THE SAN GABRIEL VALLEY. THE MARINE LAYER DEPTH SHOULD THIN OVER THE COMING DAYS AND ONSHORE FLOW WILL WEAKEN AS A STRONG RIDGE OF HIGH PRESSURE ALOFT OVER THE EASTERN STATES EXPANDS ACROSS THE SUN BELT AND RE-CENTERS INTO WEST TEXAS BY LATE SUNDAY NIGHT. NAM BUFR TIME HEIGHT SECTIONS AND DETERMINISTIC MODEL PRESSURE GRADIENTS SUGGEST THE MARINE INTRUSION AND ONSHORE FLOW REMAINING INTACT, BUT IT WILL BE MUCH THINNER AND WEAKER RESPECTIVELY. NAM AND GFS BUFR TIME HEIGHT SECTIONS SUGGEST THE MARINE LAYER DEPTH THINNING CLOSER TO NEAR 500 FEET DEEP. BY THE WEEKEND, ANY LOW CLOUDS (IF AT ALL) WILL BE CONFINED TO THE IMMEDIATE COASTAL AREAS AND PATCHY IN NATURE. THERE IS A MODERATE CHANCE THAT THE MARINE LAYER CLOUDINESS COULD BECOME NON-EXISTENT OVER THE WEEKEND. WITH LESS ONSHORE FLOW AND THE THINNER MARINE LAYER DEPTH, THE AIR MASS WILL HEAT UP. EPS ENSEMBLE MEMBERS SUGGEST A WARMING TREND TURNING MORE SIGNIFICANT OVER THE COMING DAYS AS A HOT AIR MASS WILL EXPAND INTO THE REGION. ABOVE NORMAL TEMPERATURES WILL LIKELY PERSIST INTO EARLY NEXT WEEK. HEAT HEADLINES HAVE BEEN ISSUED WITH AN EXCESSIVE HEAT WATCH IN EFFECT FOR AREAS OUTSIDE OF THE MARINE INFLUENCE. THERE IS A HIGH-TO-LIKELY CHANCE OF DANGEROUSLY HOT CONDITIONS DEVELOPING ACROSS THE INTERIOR PORTIONS OF THE AREA. ON THE PERIPHERY OF THE MARINE LAYER, A HEAT ADVISORY IS IN EFFECT ACROSS MANY VALLEY AND INTERIOR COASTAL AREAS, WHICH WILL SEE HOT TEMPERATURES CAUSING HEAT IMPACTS FOR THOSE SENSITIVE TO THE HEAT. THE FORECAST GETS TRICKY FOR SUNDAY AS THE REMNANT MOISTURE OF TROPICAL STORM ALBERTO MAKES ITS WAY ACROSS THE SONORAN DESERT AND INTO SOUTHERN CALIFORNIA. EPS ENSEMBLE MEMBERS SUGGEST KLAX PRECIPITABLE WATER VALUE MEANS CLIMBING TO 1.50 INCHES, WHICH WOULD BE ABOUT 225 PERCENT OF NORMAL FOR THIS TIME OF YEAR. THE CURRENT FORECAST INDICATES SLIGHT CHANCE POPS OVER THE SOUTHERN AND EASTERN LOS ANGELES COUNTY, BUT DETERMINISTIC SOLUTION MAINTAIN SOUTHWEST FLOW ALOFT, WHICH TYPICALLY KEEPS A LID ON THE ATMOSPHERE. DETERMINISTIC SOLUTIONS KEEP THE BEST MOISTURE AND INSTABILITY TO THE SOUTH AND EAST OF THE AREA. EPS CLOUD COVER AND QPF MEANS LOOK LESS FAVORABLE FOR ANY PRECIPITATION. IN FACT, ONLY A HANDFUL SOLUTIONS ADVERTISE QPF VALUES ACROSS THE REGION. CLOUD COVER WILL LIKELY BRING SOME COOLING DURING THE DAY, BUT OVERNIGHT LOW TEMPERATURES WILL REMAIN WARM. WHILE THE FORECAST KEEP POPS, THE MOST PROBABLE SCENARIO LOOKS TO BE WITH VERY WARM TO HOT, HUMID, AND UNCOMFORTABLE WEATHER ACROSS THE REGION WITH THE BEST CHANCE OF ANY SHOWER ACTIVITY REMAINING OUT OF THE AREA. THAT BEING SAID, POPS DO REMAIN IN THE FORECAST, BUT THERE IS STILL PLENTY OF TIME TO IRON OUT THE FINER DETAILS. .LONG TERM (MON-THU)...20/530 PM. THE REGION WILL CONTINUE TO BE UNDER THE WESTERN PORTION OF STRONG HIGH PRESSURE CENTERED OVER ARIZONA AND NEW MEXICO THROUGH THE EXTENDED PERIOD. WITH ONLY MINOR CHANGES IN THE UPPER LEVEL PATTERN, WEATHER CONDITIONS WILL BE SIMILAR FROM DAY TO DAY. TEMPERATURES WILL BE MUCH COOLER AT THE BEACHES, WITH VERY WARM- TO-HOT INTERIOR TEMPERATURES. MONDAY AND TUESDAY COULD ALSO SEE A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS. WHILE HIGH HEIGHTS WILL REMAIN THOUGH THE EXTENDED PERIOD, THE CENTER OF THE HIGH PRESSURE WILL MIGRATE TO THE WEST BY WEDNESDAY. THIS WILL CHANGE THE POSITIONING OF THE ANTICYCLONIC FLOW, AND WILL STIFLE THE STREAM OF MOSITURE INTO THE REGION. && .AVIATION...21/0150Z. AT 2356Z AT KLAX, THE MARINE LAYER WAS 1200 FEET DEEP. THE TOP OF THE INVERSION WAS AT 3800 FT WITH A TEMPERATURE OF 21 DEG C. HIGH CONFIDENCE IN DESERT TAFS, AND MODERATE CONFIDENCE IN TAFS FOR COASTAL AREAS AND COASTAL VALLEYS. VFR CONDITIONS ARE EXPECTED INTO TONIGHT FOR ALL AREAS, WITH CIG/VSBY RESTRICTIONS RETURNING TO THE COASTS AND COASTAL VALLEYS LATE TONIGHT INTO FRIDAY MORNING. GOOD CONFIDENCE IN CIGS FOR THE CENTRAL COAST, WITH MUCH LOWER CONFIDENCE OF CIGS FROM KSBA SOUTHWARD, ESPECIALLY FOR KSBA, KOXR, AND KCMA. IF CIGS MANAGE TO REACH KSBA, KOXR, AND KCMA THEY WILL BE VERY SHORT-LIVED. TIMING OF ONSET AND DISSIPATION OF CIG/VSBY RESTRICTIONS MAY BE VARY BY +/- 2 HOURS FROM CURRENT FORECASTS. BY EARLY AFTERNOON FRIDAY, VFR CONDITIONS ARE EXPECTED FOR ALL SITES. KLAX...MODERATE CONFIDENCE IN TAF. THERE IS A 20% CHANCE OF NO CIG/VSBY RESTRICTIONS TONIGHT. NO SIGNIFICANT EAST WIND COMPONENT IS EXPECTED. KBUR...HIGH CONFIDENCE IN VFR TAF AND LIGHTER WINDS. && .MARINE...20/931 PM. FOR THE OUTER WATERS, HIGH CONFIDENCE IN CURRENT FORECAST. SMALL CRAFT ADVISORY (SCA) WINDS ARE EXPECTED THROUGH FRIDAY EVENING. THEREAFTER, SCA CONDITIONS ARE NOT EXPECTED THROUGH AT LEAST EARLY NEXT WEEK. FOR THE INNER WATERS NORTH OF POINT SAL, MODERATE TO HIGH CONFIDENCE IN CURRENT FORECAST. SCA WINDS WILL REMAIN POSSIBLE THROUGH FRIDAY EVENING, HIGHEST CHANCES IN THE AFTERNOON AND EVENINGS. THEREAFTER, SCA CONDITIONS ARE NOT EXPECTED THROUGH AT LEAST EARLY NEXT WEEK. FOR THE INNER WATERS SOUTH OF POINT CONCEPTION, MODERATE TO HIGH CONFIDENCE IN CURRENT FORECAST. SCA WINDS ARE EXPECTED OVER THE WESTERN SANTA BARBARA CHANNEL THROUGH TONIGHT, WITH A 50% CHANCE TOMORROW AFTERNOON AND EVENING. OTHERWISE, SCA CONDITIONS ARE NOT EXPECTED THROUGH AT LEAST EARLY NEXT WEEK. IN ADDITION, THERE WILL BE SOME POSSIBILITY FOR A FEW THUNDERSTORMS TO IMPACT THE LOCAL WATERS THIS WEEKEND, AS REMNANT UPPER-LEVEL MOISTURE FROM TROPICAL CYCLONE ALBERTO ADVANCES INTO THE REGION. PLEASE REFERENCE THE MARINE WEATHER STATEMENT FOR ADDITIONAL INFORMATION. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...HEAT ADVISORY REMAINS IN EFFECT FROM 10 AM SATURDAY TO 8 PM PDT SUNDAY FOR ZONES 38-88-343>345-372-373-548. (SEE LAXNPWLOX). WIND ADVISORY IN EFFECT UNTIL 4 AM PDT SATURDAY FOR ZONES 349-351. (SEE LAXNPWLOX). EXCESSIVE HEAT WATCH REMAINS IN EFFECT FROM SATURDAY MORNING THROUGH SUNDAY EVENING FOR ZONES 353-376>382. (SEE LAXNPWLOX). PZ...SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT SATURDAY FOR ZONES 645-670-673-676. (SEE LAXMWWLOX). SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PDT FRIDAY FOR ZONE 650. (SEE LAXMWWLOX). &&