Forecast Discussions mentioning ACARS, received at FSL on 08/28/99

LATEST FOG PRODUCT IMAGES AS WELL AS SURFACE REPORTS INDICATE LOW CLOUDS INTO THE CENTRAL COAST OF SLO/SBA COUNTIES...AND INTO THE VTU COUNTY COAST. NO DENSE FOG AT ANY OF THE REPORTING STATIONS YET. STRONG...LOW INVERSION PRESENT OVER THE DISTRICT WITH THE MARINE LAYER ONLY 1K FEET DEEP OR SO. ACARS SOUNDING FROM LAX SHOWS THE STORY...AT 0243Z TEMP AT 990 FEET WAS 59 DEG F...THEN ROSE TO 87 DEG F AT 2080 FEET...A CHANGE OF 28 DEG F IN ONLY 1100 FEET! NEEDLESS TO SAY...GOOD CHANCE FOR AT LEAST LOCAL DENSE FOG OVERNIGHT. ALSO...WITH A LOW MARINE LAYER WOULD NOT EXPECT MUCH INLAND PENETRATION OF THE LOW CLOUDS.

00Z ETA/NGM SHOW AN ELONGATED UPPER HI STRETCHING FROM THE SRN ROCKIES TO SRN CA AND WELL OFF THE COAST REMAINING IN PLACE THRU SUN. ETA CROSS SECTIONS SHOW MONSOONAL MOISTURE MAINLY OVER THE EASTERN AND SOUTHERN DESERTS SAT AFTENROON...THEN BRING SOME INTO ERN PARTS OF THE DISTRICT FOR SUN SO SOME AFTERNOON THUNDERSTORMS CANNOT BE RULED OUT THEN FOR LAX COUNTY MOUNTAINS AND ANTELOPE VALLEY.

WITH THICKNESSES/850 MB TEMPS INCREASING WITH ONLY WEAK ONSHORE GRADIENTS EXPECTED...LOOKS LIKE AN EVEN WARMER DAY IN STORE FOR INLAND AREAS ON SAT WITH LITLE CHANGE FOR SUN.

CURRENT ZONES LOOK GOOD...SO NO UPDATES PLANNED AT THIS TIME.

IN THE EXTENDED...LOOKS LIKE ONE MORE DAY MONDAY OF HOT WEATHER OVER INLAND SECTIONS...THEN UPPER TROF FORECAST TO MOVE IN TO COOL THINGS DOWN CLOSER TO NORMAL WITH A DEEPER MARINE LAYER AND INCREASED ONSHORE FLOW FOR TUE AND WED. SOME THUNDERSTORMS POSSIBLE MAINLY EASTERN AND SOUTHERN MOUNTAINS AND DESERTS MON...OTHERWISE DRY WEATHER EXPECTED THRU THE PERIOD.

LAX 0000. SIRARD.

.LAX...SMALL CRAFT ADVISORY...SEE LAXCWFLAX.

STRATUS OR NOT IS THE QUESTION FOR THIS MORNING. SURFACE PRESSURE GRADIENTS HAVE TURNED ONSHORE BUT ARE NOT VERY IMPRESSIVE. KHQM- KSEA GRADIENTS PEAKED OUT SO FAR AT 2.2 MB AT 09Z...KOTH-KSEA +3.5 MB AT 05Z. KOLM-KBLI GRADIENTS POSITIVE BUT ONLY BY HALF A MB. THE VARIABLE THAT MAKES IT INTERESTING IS THE DEW POINTS WHICH ARE HIGH...UPPER 50S IN MANY PLACES. EVEN WITH THE HIGH DEW POINTS...THE LACK OF ANY UPPER AIR SUPPORT...FRONT STILL OUT NR 132W AND MOVING SLOWLY EASTWARD WITH PARENT LOW IN THE GULF OF ALASKA MOVING NORTHWARD...ACARS SOUNDINGS SHOWING 850 MB TEMPS OVER KSEA STILL AROUND +20C ALONG WITH JUST LIGHT SWLY FLOW...10 KNOTS OR LESS... ALL THE WAY UP THROUGH 5000 FEET...AND MODELS ONLY DROP 500 MB HEIGHTS FROM 583 DM TO 581 DM BY THIS AFTERNOON WILL GO WITH A WEAK MARINE PUSH WITH STRATUS GETTING TO EXTREME SOUTHERN PORTION PUGET SOUND. FOG/ST SATELLITE IMAGERY HAS LEADING EDGE OF THE STRATUS BETWEEN KHQM AND KSHN AT 09Z. WITH THE HIGH DEW POINTS AND LIGHT SURFACE GRADIENTS...AREAS OF FOG IN THE FAVORED PLACES LIKE ARLINGTON...OLYMPIA AND THE I-5 CORRIDOR SOUTH OF KOLM. ONSHORE SURFACE GRADIENTS CONTINUE THROUGH THE DAY. WHAT IS LEFT OF THE FRONT DRAGGING ACROSS WESTERN WASHINGTON TONIGHT. THIS WILL HELP ENHANCE THE MARINE LAYER FOR MORE WIDESPREAD STRATUS INLAND FOR SUNDAY MORNING. WITH THE ONSHORE GRADIENTS CONTINUING THROUGHOUT THE DAY SUNDAY MAX TEMPS AT LEAST 5 DEGREES COOLER THAN SATURDAY. .EXTENDED...BOTH MRF AND EURO BRING UPPER LEVEL TROUGH THROUGH ON MONDAY FOR COOL AND SHOWERY DAY. NWLY FLOW ALOFT TUESDAY WITH TROUGH AXIS TO THE EAST MAKING TUESDAY THE DRIEST OF THE THREE DAYS. MRF BRINGS A SHORTWAVE DOWN THE BC COAST WED REACHING WESTERN WA IN THE AFTERNOON. EURO IS SOMEWHAT WEAKER WITH THIS FEATURE. EITHER WAY...GENERAL TROFINESS OVER THE AREA WILL KEEP MENTION OF SHOWERS IN THE FORECAST. A COOL END TO AUGUST. FELTON

UIL 222 SEA 001 OLM 001

.KATX...VCP32/CSR32.

.SEW...SCA STRAIT.

SATELLITE SHOWS GOOD MARINE LAYER THIS MORNING PUSHING WELL INTO THE COASTAL VALLEYS. AIRCRAFT REPORTS FROM THE BAY AREA INDICATE TOPS OF 1500 TO 1800 FEET. STRATUS LAYER FAIRLY SOLID NEAR AND OFFSHORE AS WELL. ONSHORE GRADIENT IS A LITTLE LESS THAN 2 MB FROM SFO TO SAC. THIS SHOULD BE ENOUGH TO KEEP SCA IN THE NORTH BAY. UPPER LOW WHICH DISRUPTED TYPICAL SUMMER PATTERN IS MOVING OUT OF NORTHEAST CALIFORNIA. SATELLITE MOISTURE LOOP SHOWS DRYING ALOFT OVER THE PAST 24 HOURS. SMALL BREAKS IN THE STRATUS ALONG PORTIONS OF THE PENINSULA ALREADY THIS MORNING. STRATUS SHOULD GRADUALLY CLEAR BACK TO NEAR THE COAST BY THIS AFTERNOON.

NEXT SYSTEM UPSTREAM APPEARS STRONG FOR LATE AUGUST...BUT THOSE UPPER TROUGHS AND LOWS CONTINUE TO MOVE OVER THE WEST. NEW ETA SHOWS HEIGHTS ALOFT AND 1000 TO 500 MB THICKNESS RISE SLOWLY NEXT 24 HOURS. HOWEVER VALUES BEGIN TO LOWER LATE SUNDAY AND SUNDAY NIGHT AS UPPER TROUGH APPROACHES THE WEST COAST. SURFACE PRESSURE GRADIENT OVER THE DISTRICT IS FAIRLY FLAT TODAY...BUT DOES INCREASE SUNDAY AFTERNOON AND EVEN MORE ON MONDAY AS WEAKENING COLD FRONT MOVES INTO NORTHERN CALIFORNIA. THIS SHOULD INCREASE WINDS ALONG THE COAST AND LOWER TEMPERATURES OVER THE INTERIOR MONDAY AND TUESDAY AND BY MONDAY AND TUESDAY DISRUPT THE STRATUS LAYER AGAIN. ALL POPS ZERO. HOFFMANN

.SFO...TDA...SCA...SFO BAY NORTH OF THE BAY BRIDGE.