Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000 FXUS66 KLOX 301620 AFDLOX SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 920 AM PDT MON MAR 30 2015 .SYNOPSIS... COOLER WEATHER IS EXPECTED EARLY THIS WEEK DUE TO ONSHORE FLOW. NIGHT THROUGH MORNING LOW CLOUDS AND FOG WILL BE POSSIBLE ALONG PARTS OF THE COAST. GUSTY NORTHWEST TO NORTH WINDS WILL DEVELOP FOR PARTS OF THE AREA ON TUESDAY AND WEDNESDAY AS SEVERAL MOISTURE STARVED FRONTS PASS TO THE NORTH. WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED LATE IN THE WEEK AS SANTA ANA CONDITIONS DEVELOP. && .SHORT TERM (TODAY-WED)...A BIT OF A COOLING TREND TODAY THROUGH THE MIDDLE OF THE WEEK. LOCAL PROFILERS AND SOUNDINGS INDICATE 3-6 DEGREES OF COOLING BELOW 2000` WHICH IS NEAR THE TOP OF THE MARINE LYR THIS MORNING. THE FORECAST LOOKS ON TRACK THROUGH THE WEEKEND AND NOT EXPECTING MUCH CHANGE FROM WHAT HAS ALREADY BEEN DISCUSSED. ***FROM PREVIOUS DISCUSSION*** A TROF APPROACHES THE AREA TUESDAY AND ONSHORE FLOW TO THE EAST REALLY INCREASES. THIS SHOULD ALLOW A BETTER MARNE LAYER CLOUD PATTERN TO FORM WITH CLOUDS OVER MOST OF THE COAST AND MUCH OF THE VLYS. THERE WILL BE DECENT WEST WINDS IN THE MTNS AND DESERTS. MAX TEMPS WILL FALL ACROSS THE BOARD BUT WILL STILL BE ABOVE NORMAL. STRONG NORTH GRADIENTS SET UP TUESDAY NIGHT AND THERE WILL BE ANOTHER ROUND OF SUNDOWNERS AND I-5 CORRIDOR WINDS. THE VLYS WILL ALSO SEE SOME NORTH WINDS. SOME LOW END ADVISORIES MAY BE NEEDED FOR THE OVERNIGHT AND WEDNESDAY MORNING HOURS. THE NORTH PUSH WILL ELIMINATE THE MARINE LAYER STRATUS EVERYWHERE EXCEPT THE SRN LA COAST. THERE WILL BE SOME COLD AIR ADVECTION WHICH WILL SERVE TO COOL THINGS OFF...ESP INLAND BUT THERE WILL ALSO BE SOME COMPRESSIONAL HEATING WHICH WILL NEGATE OR EVEN OVERWHELM SOME OF THE COLD AIR. OVER ALL TEMPS WILL BE A MIXED BAG. THE BIGGEST CHANGE WILL BE INLAND AWAY FROM THE DOWNSLOPE FLOW WHERE IT WILL BE COOLER. .LONG TERM (THU-SUN)... THU WILL BE MUCH LIKE WEDNESDAY WITH A GOOD NORTH PUSH AND POSSIBLE LOW END WIND ADVISORIES ACROSS THE I-5 CORRIDOR AND THE SBA SOUTH COAST. THE COOL AIR WILL BE GONE AND THIS WILL ALLOW FOR SLIGHTLY WARMER TEMPS THAN ON WEDNESDAY. THE MARINE STRATUS AGAIN WILL BE CONFINED TO THE LA SOUTH COAST AND THAT FCST MAY BE ON THE PESSIMISTIC SIDE. THERE WILL BE SOME NORTH SLOPE CLOUDS DUE TO THE STRONG NORTH TO SOUTH FLOW OUT OF THE CENTRAL VLY. QUICK HITTING RIDGE AND SANTA ANA WIND EVENT IS SLATED FOR FRIDAY. A 1034 MB SFC HIGH MOVES INTO NV FRIDAY MORNING AND WILL GENERATE GUSTY NEAR ADVISORY LEVEL NE WINDS ACROSS LA AND VTA COUNTY. MAX TEMPS WILL SOAR INTO THE MID AND UPPER 80S ACROSS MUCH OF THE CST AND VLYS. SKIES WILL BE SUNNY WITH NARY A TRACE OF MARINE LAYER STRATUS. STILL OFFSHORE FOR SATURDAY BUT THE RIDGE ALOFT WILL BE REPLACED BY A TROF SO THIS WILL KNOCK A FEW DEGREES OFF OF THE TEMPS AS WILL AN EARLIER SEA BREEZE SINCE THE OFFSHORE FLOW WILL RELAX EARLIER IN THE DAY AS THE TROFS INFLUENCE BEGINS TO ASSERT ITSELF. STILL NO LOW CLOUDS ALTHOUGH SKIES MAY BE PARTLY CLOUDY AS THE RESULT OF SOME MID LEVEL CLOUDS ASSOC WITH THE TROF. A QUICK AND STRONG SWITCH TO ONSHORE FLOW SAT NIGHT ALONG WITH TROFING ALOFT WILL ALSO A DEEP AND PENETRATING MARINE STRATUS LAYER TO FORM AND MOVE ACROSS THE COASTS AND INTO THE VLYS. COULD BE SOME SLOW CLEARING SUNDAY AND MAX TEMPS WILL COLLAPSE. && .AVIATION...30/12Z AT 1120Z AT KLAX... THE INVERSION WAS 2400 FEET DEEP WITH THE TOP AT 3300 FEET AND A TEMPERATURE OF 20 DEGREES CELSIUS. OVERALL... MODERATE CONFIDENCE IN THE 12Z TAFS. LESS CONFIDENT IN THE COASTAL AND ADJACENT VALLEY SITES DUE TO UNCERTAINTY IN THE TIMING... LOCATION... AND INTENSITY OF THE MARINE INTRUSION. MORE CONFIDENT IN THE VFR CONDITIONS FOR LOCATIONS FARTHER INLAND. BRIEF PERIODS OF VLIFR/LIFR CONDITIONS ARE POSSIBLE AT COASTAL SITES THROUGH 17Z WITH LINGERING MVFR CONDITIONS POSSIBLE THROUGH 20Z. OTHERWISE AND ELSEWHERE VFR CONDITIONS WILL PREVAIL. THE MARINE INTRUSION WILL RETURN TONIGHT ALONG THE ENTIRE FOUR COUNTY COASTLINE. KLAX... WEAK TO MODERATE CONFIDENCE IN THE 12Z TAF. THE REDUCED CONFIDENCE IS DUE TO UNCERTAINTY IN THE TIMING AND INTENSITY OF THE MARINE INTRUSION. BRIEF PERIODS OF LIFR CONDITIONS THROUGH 17Z WITH LINGERING MVFR CONDITIONS POSSIBLE THROUGH 20Z. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH THE DAY THEN THE MARINE INTRUSION RETURNS AFT 07Z. KBUR... MODERATE CONFIDENCE IN THE 12Z TAF. THE REDUCED CONFIDENCE IS DUE TO UNCERTAINTY IN THE POSSIBILITY OF THE MARINE INTRUSION REACHING KBUR. CHANCES ARE TEN PERCENT OF THIS OCCURRING. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH THE DAY THEN A SLIGHT CHANCE OF REDUCED CIGS/VSBY RETURNS AFT 10Z,. && .MARINE...30/300 AM SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE CENTRAL AND SOUTHERN OUTER WATERS THROUGH LATE TONIGHT. THE WINDS WILL LIKELY INCREASE OVERNIGHT TONIGHT AND A GALE WATCH IS IN EFFECT FOR TUESDAY MORNING THROUGH THURSDAY NIGHT FOR THE ENTIRE OUTER WATERS AND THE NEARSHORE ZONE ALONG THE CENTRAL COAST. HOWEVER THE WINDS DO NOT APPEAR TO BE DEVELOPING AS STRONGLY AS FIRST THOUGHT AND SMALL CRAFT ADVISORIES MAY BE EXTENDED FOR AT LEAST A PORTION OF THE WATCH PERIOD. A FRESH WEST-NORTHWEST SWELL WILL MIX IN WITH LOCALLY GENERATED SEAS THROUGH WEDNESDAY AND STEEP COMBINED SEAS ABOVE 10 FEET WILL LIKELY PERSIST NEAR SHORE THROUGH FRIDAY. PATCHY DENSE FOG WITH VISIBILITIES LESS THAN ONE NM ARE EXPECTED IN THE OVERNIGHT PERIODS FOR THE NEXT COUPLE OF NIGHTS. && .BEACHES...A LONG PERIOD SWELL FROM THEN SOUTHERN HEMISPHERE WILL CONTINUE THROUGH THIS EVENING. EXPECT ELEVATED SURF AND STRONG RIP CURRENTS AND LONGSHORE CURRENTS ON BEACHES ALONG EXPOSED SOUTH FACING SHORES. && .CLIMATE... ***WARMEST MARCH ON RECORD IN MANY LOCATIONS*** WITH JUST TWO DAYS LEFT IN THE MONTH...CONFIDENCE IS HIGH THAT MARCH 2015 WILL BE THE WARMEST MARCH SINCE WEATHER RECORDS BEGAN AT MOST LOCATIONS IN SOUTHWESTERN CALIFORNIA. THIS INCLUDES DOWNTOWN LOS ANGELES...WHERE RECORDS BEGAN IN JULY 1877...AND RECORDS FOR MARCH BEGAN IN 1878. OUT OF A TOTAL OF 138 MARCHES (INCLUDING THIS ONE)...MARCH 2015 IS RUNNING ABOUT 2 DEGREES WARMER THAN THE NEXT WARMEST MARCH...MARCH 1931. BREAKING A MONTHLY AVERAGE TEMPERATURE RECORD BY ABOUT 2 DEGREES IS VERY UNUSUAL...ESPECIALLY ONE WITH A PERIOD OF RECORD ALL THE WAY BACK TO 1878. && $$ PUBLIC...MW/RORKE AVIATION...KJ MARINE...KJ SYNOPSIS...SUKUP CLIMATE...BRUNO WWW.WEATHER.GOV/LOSANGELES

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