Forecast Discussions mentioning ACARS, received at FSL on 06/28/99

...SYNOPSIS... BUILDING HIGH PRESSURE ALOFT AND WEAKER ONSHORE FLOW WILL BRING WARMER WEATHER INTO MID-WEEK. NIGHT AND MORNING LOW CLOUDS AND FOG WILL BE LESS WIDESPREAD IN THE NEXT FEW DAYS.

...DISCUSSION... LOW CLOUDS CLEARED OUR ENTIRE COASTLINE TODAY...THOUGH JUST TO THE SOUTH IN BAJA...LOW CLOUDS COVERED MOST OF THE COAST. NO RECENT ACARS SOUNDINGS WERE AVAILABLE FROM SAN...BUT ACARS SOUNDINGS FROM LAX SHOW THE MARINE INVERSION SOMEWHERE AROUND 2000 FEET AND SHOW IT WEAKENING IN STRENGTH. SOME SLIGHT COOLING WAS EVIDENT ABOVE THE INVERSION...WHICH IS WHY INLAND EMPIRE/MTN/DESERT AREAS WERE NOT WARMER TODAY THAN YESTERDAY...AT LEAST SO FAR.

THE WEAK TROUGHING AND AN EDDY REMAINED OVER OUR AREA THIS MORNING. HOWEVER...BOTH HAVE WEAKENED ARE EXPECTED TO CONTINUE TO DO SO THROUGH MONDAY. THE WINDS AT PT CONCEPTION CONTINUE TO DECREASE AND ARE NOW ONLY NW AT 6 KT AS THE REMNANTS OF THE EDDY DRIFT UP INTO THAT AREA. THE 850 MB FLOW SHOULD BECOME WEAKLY ANTI-CYCLONIC OVER OUR AREA TONIGHT TO ASSIST IN THE WARMING TREND AS ANTI-CYCLONIC LOW-LEVEL FLOW RESULTS IN EARLIER CLEARING OF THE MORNING LOW CLOUDS MON/TUE. ONSHORE FLOW CONTINUES THROUGH THE PERIOD...THOUGH THE FLOW IS QUITE WEAK LATE TONIGHT...SO THIS SHOULD GIVE COASTAL TEMPS A BOOST MONDAY. TEMPS MAY FLATTEN OUT THERE TUESDAY DUE TO A SLIGHT INCREASE IN ONSHORE FLOW DESPITE A MUCH WARMER PROFILE ALOFT. INLAND/MTN/DESERT TEMPS WILL SEE A STEADY INCREASE THROUGH ABOUT WEDNESDAY.

AN EAST-WEST RIDGE OF HIGH PRESSURE WILL HAVE ITS AXIS RIGHT OVER SAN DIEGO MOST OF THE WEEK...SO THIS SHOULD BRING ABOVE NORMAL TEMPS TO MOST AREAS EXCEPT THE IMMEDIATE COAST. THE LATEST RUN OF THE MRF HAS TEMPERED THE HEAT SLIGHTLY THOUGH FOR LATE IN THE WEEK AS WEAK TROUGHING IS NOW PROGGED OVER THE PAC NW INSTEAD OF OVER THE ROCKIES. HOWEVER...HEIGHTS/THICKNESSES/TEMPS ALOFT WILL STILL BE HIGH ENOUGH HERE TO BRING A LOT OF HEAT...AT LEAST INLAND. WITH THE MAIN HIGH ALOFT A BIT FURTHER SOUTH THAN PREVIOUSLY PROGGED...THE CHANCE OF MTN/DESERT TSTORMS ANYTIME THIS WEEK IS NEAR ZERO.

SAN 0000

.SAN...NONE.

MAXWELL

FAIRLY DECENT EAST-SOUTHEAST LOW LEVEL FLOW OVER THE PLAINS AT THIS TIME....WITH PLENTY OF UPPER 50S DEW POINTS EVERYWHERE. LAPS DATA SHOWING A STRONG LOW LEVEL THETA-E AXIS OVER US...WITH THE BEST MOISTURE CONVERGENCE PILING UP ALONG THE FOOTHILLS AND FRONT RANGE. RADAR SHOWING SOME A DECENT BOUNDARY NORTH-SOUTH ACROSS DOUGLAS COUNTY AND AREA OBSERVATIONS ARE HINTING AT A DENVER CYCLONE SETTING UP. SATELLITE PICTURES ARE SHOWING A BOUNDARY ACROSS THE NORTHEAST CORNER OF THE PLAINS...AND SOMETHING ALONG THE CHEYENNE RIDGE...WITH ONLY MINIMAL CUMULUS DEVELOPMENT AT THIS TIME OVER THE CWA. SOME CONVECTION GOING NORTH OF THE BORDER IN WYOMING AND NEBRASKA...BUT NONE YET HERE. TROUBLE IS...NOT ABLE TO WARM ENOUGH YET TO BREAK THE INVERSIONS ABOVE US. LATEST ACARS SOUNDINGS STILL SHOWING STRONG 700 MB CAP OVER THE AREA...AND A LITTLE ONE AT ABOUT 450 MB. THE CAP WILL BE HARD TO GO AGAIN THIS AFTERNOON...BUT IF IT CAN ...LAPS SHOWING SOME 2000-4000 JOULES OF CAPE TO WORK WITH RIGHT ALONG THE URBAN CORRIDOR AT THIS TIME. WATER VAPOR PICTURES STILL SHOWING THE UPPER TROUGH AXIS WELL UPSTREAM...WITH THE RUC/MESOETA GETTING THEIR Q-G ASCENT/THERMAL TROUGH INTO HERE AFTER 00Z. 80-100 KNOT JET NOW IN THE AREA AS EVIDENT BY PROFILERS AND RAWS MOUNTAIN WIND SENSORS. THIS IS PROGGED TO CONTINUE OVERNIGHT. I STILL THINK WE'LL GET THE STORMS...SOME SEVERE TOO.

FOR MONDAY THROUGH TUESDAY...FAIRLY STRONG WEST-NORTHWESTERLY FLOW ALOFT IS PROGGED...WITH THE DIV-Q/POTENTIAL VORTICITY/UPPER WIND GRIDS SHOWING SOME VERY WEAK SYNOPTIC SCALE LIFT FROM TIME TO TIME. WATER VAPOR PICTURE PROGS WOULD BE NICE FOR LOCATING THESE FEATURES. THE LOW LEVEL PRESSURE/WIND/MOISTURE GRIDS KEEP SHOWING SURGES MOVING INTO THE PLAINS...WITH THE NEXT ONE IN HERE AROUND 18Z MONDAY NOONTIME...THEN ANOTHER IN LATE TUESDAY AFTERNOON/EVENING. THEY ALSO KEEP AN EASTERLY COMPONENT TO THE LOW LEVEL FLOW THROUGHOUT THE PERIOD...AND DECENT THETA-E AXES AT MANY LEVELS. CROSS SECTIONS SHOW GREAT POTENTIAL INSTABILITY AS WELL AND MODIFIED FORECAST SOUNDING SHOWING 2000 J/KG PLUS CAPES FOR THE PLAINS BOTH DAYS. THE WIND PROFILES SHOW BEST SHEAR FOR STORMS TUESDAY AFTERNOON (SOUTHEAST SURFACE FLOW)...WITH MONDAY AFTERNOON IN THE NORTHEAST LOW LEVEL FLOW. THE LAPSE RATES ARE VERY STEEP BELOW 500 MB BOTH AFTERNOONS...BUT SOME 500/400 MB CAPPING INDICATED IN THE TEMPERATURE GRIDS OFF AND ON THROUGH THE NEXT TWO DAYS. WITH ALL THE MOISTURE EXPECTED...EASTERLY FLOW...AND LATE EVENING MCS'S TO CONTEND WITH...MORNING STRATUS IS A GOOD BET AS WELL. BASICALLY IT WILL BE MORE OF THE SAME...WITH PLENTY OF ENERGY AVAILABLE FOR SEVERE WEATHER BUT TRYING TO FIGURE OUT THE MID LEVEL CAP SITUATION ... THE LOW LEVEL STABILIZATION OR NOT...AND ANY HELP FROM A SYNOPTIC SCALE LIFTING MECHANISM OR NOT. RIGHT NOW WILL GO WITH SOME AFTERNOON/EVENING STORMS...MORE ON TUESDAY...AND MORNING STRATUS. TEMPERATURES WILL BE AT OR BELOW THE SEASONAL NORMS FOR THE NEXT TWO DAYS.

FOR THE EXTENDED PERIOD...THE LAST 4 OR 5 MRF RUNS HAVE ALL SHOWN A DECENT UPPER TROUGH OVER COLORADO AROUND WEDNESDAY...HOWEVER THE LATEST RUN (06/27 00Z) NOW JUST INDICATES PRETTY DECENT WEST- NORTHWEST FLOW ALOFT...NO TROUGH ANYMORE? ANYWAY...THIS WEST- NORTHWEST FLOW IS PROGGED THROUGH THE EXTENDED PERIOD WITH A COUPLE OF SURGES OF UPSLOPE AT THE SURFACE. WITH THE NORTHWEST FLOW USUALLY HAVING PLENTY OF SYNOPTIC SCALE ENERGY EMBEDDED IN IT...AND THE GRIDS SHOWING SOME MOISTURE OVER THE EASTERN HALF...WILL KEEP "CHANCE" IN ALL THREE DAYS. RJK

.DEN...NONE.

IN SHORT TERM...BUILDING UPPER RIDGE AND WEAKER ONSHORE FLOW HAVE SHRUNK THE MARINE LAYER THIS MORNING...WITH ACARS DATA INDICATING INVERSION BASE 1000-1500 FEET. NET RESULT WILL BE TO CONFINE MOST STRATUS/FOG TO COASTAL ZONES THIS MORNING FROM SAN LUIS OBISPO TO LA COUNTIES...WITH ONLY VERY PATCHY STRATUS/DENSE FOG IN COASTAL VALLEYS OF VENTURA/LA COUNTIES. DENSE FOG APPEARS WIDESPREAD ENOUGH TO WARRANT DENSE FOG ADVISORY FOR CENTRAL COAST...WILL ISSUE UNTIL 9 AM. AS THE MARINE LAYER HAS SHRUNK...INVERSION HAS STRENGTHENED. THEREFORE...BELIEVE BEACHES WILL SEE SOMEWHAT LIMITED CLEARING TODAY. OTHER THAN MORNING MARINE LAYER...SKIES WILL BE SUNNY TODAY ACROSS THE AREA.

FOR TONIGHT/TUESDAY...MODELS CONTINUE TO BUID UPPER RIDGE OVER THE DISTRICT. THEREFORE...MARINE LAYER WILL CONTINUE TO SHRINK TONIGHT WITH STRATUS/FOG CONFINED ONLY TO THE COASTAL ZONES. IN FACT...THE POSSIBILITY EXISTS FOR SOME WIDESPREAD COASTAL DENSE FOG TONIGHT AND TUESDAY MORNING FROM SOUTHERN SBA COUNTY TO LA COUNTY. FUTURE SHIFTS WILL HAVE TO WATCH THAT SITUATION CLOSELY. OTHERWISE...BUILDING UPPER RIDGE WILL CONTINUE TO KEEP SKIES SUNNY THROUGH TUESDAY.

AS FOR TEMPS...WARMING TREND WILL CONTINUE THROUGH TUESDAY. WITH PROFILER DATA SHOWING GOOD BOUNDARY LAYER WARMING AND LESS MARINE INFLUENCE...WILL EXPECT 2-5 DEGREES WARMING TODAY WITH BEST WARMING OCCURRING IN THE VALLEYS. ON TUESDAY...ANOTHER 2-4 DEGREES OF WARMING EXPECTED...WITH LIMITED MARINE INFLUENCE AND RISING THICKNESSES. IN FACT...SOME VALLEY AREAS SHOULD PUSH 100 DEGREES ON TUESDAY.

FOR EXTENDED...UPPER RIDGE REMAINS DOMINANT FEATURE THROUGH THE PERIOD. THEREFORE...OTHER THAN SOME COASTAL STRATUS/FOG...SKIES WILL REMAIN CLEAR THROUGH THE PERIOD. ALSO...WARM TEMPS WILL CONTINUE THROUGH THE PERIOD...WITH SOME VALLEY AREAS ABOVE 100.

LAX 000. THOMPSON.

.LAX...DENSE FOG ADVISORY...SEE LAXNPWLAX.