Forecast Discussions mentioning ACARS, received at FSL on 06/06/99

LATEST RAMSDIS FOG PRODUCT SHOWS LOW CLOUDS INTO CENTRAL COAST WITH PATCHY LOW CLOUDS ALONG LAX/VTU COUNTY COASTS. 00Z SOUNDINGS SHOW MARINE LAYER NEAR 1K FT AT VBG AND NEAR 2K FT AT NKX. ACARS SOUNDINGS AT LAX PAST SEVERAL HOURS NOT GOING BELOW 2K FT...AND USC PROFILER DATA NOT AVAILABLE...SO DIFFICULT TO TELL MARINE LAYER DEPTH THERE ALTHOUGH SOME CLOUDS AROUND 800 FT SHOWING UP AT LAX THIS PAST HOUR. SOME ONSHORE GRADIENTS ACROSS LAX COUNTY (+4 TO +6 MB) BUT HARD TO TELL IF THIS WILL BE STRONG ENOUGH FOR LOW CLOUDS TO MAKE IT INTO THE VALLEYS OVERNIGHT. GIVEN THE UNCERTAINTY ON MARINE LAYER DEPTH OVER LAX...CURRENT FORECAST FOR PATCHY LOW CLOUDS IN THE VALLEYS LOOKS GOOD AT THIS TIME.

00Z NGM/ETA IN GENERAL AGREEMENT WITH UPPER LOW OVER COASTAL BRITISH COLUMBIA SLIDING SLOWLY E AND SE DURING THE NEXT 48 HOURS WITH ITS ASSOCIATED UPPER TROF EXTENDING DOWN THE W COAST INTO CA. WHAT THIS WILL DO IS KEEP THE DISTRICT IN A TYPICAL MARINE LAYER REGIME FOR THE COAST INTO THE VALLEYS WITH CLEAR SKIES FOR THE MOUNTAINS AND ANTELOPE VALLEY. DEEPER MARINE LAYER IS EXPECTED SUN NIGHT IN RESPONSE TO LOWERING 500 MB HEIGHTS OVER THE REGION AS THE TROF MOVES IN. THIS SHOULD ALLOW FOR AREAS OF LOW CLOUDS TO MOVE INTO THE VALLEYS SUN NIGHT. TEMPS SLIGHTLY WARMER SUN THAN THEY WERE TODAY...THEN A FEW DEGREES COOLER FOR MON...ESPECIALLY OVER THE COAST AND VALLEYS... EXCEPT IT SHOULD REMAIN RATHER WARM FOR INTERIOR VALLEYS OF SLO AND SBA COUNTIES. FORECAST UPDATE BY 915 PM FOR JUST MINOR CHANGES.

NOT MUCH CHANGE IN THE GENERAL WEATHER DURING THE EXTENDED PERIOD. SOME MINOR DIFFERENCES WITH MEDIUM RANGE MODELS OVER SOCAL...BUT AS A WHOLE IT APPEARS MORE COASTAL LOW CLOUDS AND FOG DURING THE NIGHT AND MORNING HOURS...OTHERWISE MOSTLY CLEAR EVERYWHERE WITH A SLOW WARMING TREND. TEMPS SLIGHTLY ABOVE NORMAL BY THURSDAY...ESPECIALLY INLAND AREAS AND THE DESERTS.

LAX 0000. SIRARD.

.LAX...GALE WARNING SUN AFTERNOON...SEE LAXCWFLAX. SMALL CRAFT ADVISORY...SEE LAXCWFLAX.

THANKFULLY...RETURNING TO A MARINE LAYER FORECAST MODE THE NEXT FEW DAYS. 12Z MODELS IN VERY GOOD SYNOPTIC AGREEMENT OVER THE NEXT 48 HOURS. UPPER RIDGE WILL CONTINUE TO BUILD OVER THE AREA THIS AFTERNOON AND TONIGHT...SHRINKING THE MARINE LAYER. IN FACT...LATEST ACARS SOUNDINGS INDICATE MARINE INVERISON ALREADY DOWN TO AROUND 2000 FEET. WILL EXPECT CONTINUED SHRINKING OVERNIGHT...LIMITING MOST STRATUS/FOG TO COASTAL ZONES...WITH ONLY PATCHY STRATUS/FOG EXEPCTED FOR COASTAL VALLEYS AND THE SLO COUNTY INTERIOR VALLEYS. FOR SUNDAY NIGHT/MONDAY...UPPER TROUGH DEVELOPS OVER THE AREA...WHICH WILL COMBINE WITH STRENGTHENING ONSHORE FLOW...TO DEEPEN MARINE LAYER...RESULTING IN MORE WIDESPREAD STRATUS/FOG FOR VALLEY AREAS. FOR MOUNTAIN/DESERT AREAS...MOSTLY CLEAR SKIES WILL PREVAIL THROUGH MONDAY.

AS FOR TEMPS...12Z MODELS INDICATE GOOD THCKNESS RISES ON SUNDAY. THEREFORE...ALL AREAS SHOULD WARM ANYWHERE FROM 3 TO 5 DEGREES SUNDAY AFTERNOON...ESPECIALLY INLAND AREAS. ON MONDAY...THICKNESSES FALL SLIGHTLY...SO SOME SLIGHT COOLING FOR INLAND AREAS. COASTAL/VALLEY AREAS WILL COOL MORE NOTICEABLY MONDAY THANKS TO INCREASED MARINE INFLUENCE.

LAX 0000. THOMPSON.

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

...SYNOPSIS... WEAK HIGH PRESSURE WILL BRING FAIR WEATHER THROUGH SUNDAY. A WEAK TROUGH OF LOW PRESSURE FROM THE PACIFIC WILL MOVE THROUGH SUNDAY NIGHT AND MONDAY BRINGING SOME COOLING MOST AREAS ALONG WITH A DEEPER MARINE LAYER SUNDAY NIGHT AND MONDAY. THIS WILL ALLOW THE LOW CLOUDS AND FOG TO MOVE INTO THE INLAND VALLEYS OVERNIGHT SUNDAY. OTHERWISE FAIR WEATHER WILL CONTINUE INTO MONDAY.

...DISCUSSION... TEMPERATURES ARE ABOUT 5 TO 10 DEGREES HIGHER AT THE LOWER ELEVATIONS AND AS MUCH AS 20 DEGREES HIGHER IN THE MOUNTAINS WHEN COMPARED TO 24 HOURS AGO. THE NOONTIME TEMPERATURE FROM THE ALERT GAUGE ON SANTIAGO PEAK IN THE SANTA ANA MOUNTAINS WAS 58 DEGREES... UP FROM 39 DEGREES AT NOON ON FRIDAY. RECENT ACARS SOUNDINGS OVER SAN AND LAX PUT THE TOP OF THE MARINE LAYER AT 2000 FEET. THE SOUNDING OVER SAN SHOWED ANOTHER INVERSION AROUND 10000 FEET WITH THE BASE OF THIS INVERSION RIGHT AT THE FREEZING LEVEL. THIS INVERSION IS NOT EVIDENT ON THE SOUNDING OUT OF LAX. IT APPEARS THE FREEZING LEVEL OUR SAN SHOULD TAKE A JUMP TO AROUND 12000 FEET THIS AFTERNOON.

12Z MODELS ARE IN GENERAL AGREEMENT THROUGH 48 HOURS WITH THE S/WV RIDGE MOVING THROUGH TONIGHT AND SUNDAY FOLLOWED BY THE NEXT S/WV TROUGH MOVING INTO THE WEST COAST. THE AVN IS ACTUALLY A LITTLE FURTHER SOUTH WITH THE LOW THAN LAST NIGHTS MRF SLIDING THE SOUTHEAST ACROSS THE PACIFIC NORTHWEST ENDING UP OVER SOUTH CENTRAL OREGON BY 72 HOURS BETWEEN KLMT AND KBNO WHILE THE MRF HAD IT NEAR KALW AT THE SAME TIME. HEIGHTS REMAIN FAIRLY HIGH OVER SOUTHERN CALIFORNIA SO THE TROUGH WILL BRING SOME LOWERING OF THICKNESS FOR SOME COOLING ALL AREAS AND A DEEPER MARINE LAYER AND ONSHORE FLOW. THIS WILL ALLOW THE LOW CLOUDS TO PUSH INLAND TO THE COASTAL SLOPES OF THE MOUNTAINS BY MONDAY MORNING THEN CLEARING BACK TO NEAR THE COAST ON MONDAY.

FOR TONIGHT...MARINE LAYER CONTINUES TO BE SQUASHED AS THE RIDGING AND INCREASED SUBSIDENCE TAKES PLACE. THIS SHOULD LIMIT ANY ST/FOG TO THE IMMEDIATE COAST LATE TONIGHT AND SUNDAY MORNING. NO SIGN OF ANY EDDY AT THIS TIME AND WIND NEAR POINT CONCEPTION NOT STRONG ENOUGH TO SUSTAIN AN EDDY THROUGH TONIGHT.

MEDIUM RANGE MODELS SHOW THE LOW LIFTING SLOWLY TO THE NORTHEAST DURING THE PERIOD WITH SLOWLY RISING HEIGHTS DURING THE LATTER PART OF NEXT WEEK. THE ECMWF AND UKMET MODELS MAINTAIN MORE TROUGHINESS OVER THE WEST THAN THE MRF THROUGH THE PERIOD.

SAN 0000

.SAN...NONE.

HORTON

NO EDDY SEEN ON SATELLITE BUT SEE STRATUS BEING PUSHED IN TO AREA. GOOD STRATUS COVERAGE CENTRAL COAST AND SEE A FINGER OF STRATUS SURGING DOWN SALINAS VALLEYS. FIGURE ALL COASTAL AREAS WILL BE WELL COVERED BY SUNRISE WITH SOME PATCHY STUFF IN THE VALLEYS AS ACARS PEGS THE MARINE LAYER AT 4000 FEET.

NOT MUCH MODEL DISAGREEMENT WITH A CONSENSUS OPINION THAT UPPER LOW NEAR VANCOUVER WILL TRANSLATE VERY SLOWLY EASTWARD AND INCREASE CYCLONIC CURVETURE OVER US WHICH SHOULD RESULT IN A DEEPER MARINE LAYER MONDAY.

TEMPS...WARMER TODAY AND THEN COOLER MONDAY IN AREAS AFFECTED BY MARINE LAYER SLIGHT COOLING INLAND MONDAY AS RESULT OF TROFING.

WINDS...ONSHORE PUSH A LITTLE BETTER EACH DAY AND THUS A LITTLE WINDIER EACH DAY BUT STILL BELOW WADS.

MEDIUM MODELS NOT MARCHING LOCK STEP BUT ALL INDICATE A RELATIVLY STATIC CYCLONIC FLOW PATTEN WITH AN EQUALLY STATIC ONSHORE SURFACE FLOW PATTERN. I SEE LITTLE CHANGE IN STORE FOR US THIS WEEK.

LAX 000. RORKE.

.LAX...GALE WARNING AND SMALL CRAFT ADVISORY...SEE LAXCWFLAX.