Forecast Discussions mentioning ACARS, received at FSL on 04/16/00

...SYNOPSIS... ONSHORE FLOW AND A DEEP MARINE LAYER WILL CONTINUE LOW CLOUDS WEST OF THE MOUNTAINS TONIGHT AND EARLY SUNDAY. A STORM SYSTEM WILL BRING RAIN TO THE AREA MAINLY MONDAY AFTERNOON INTO TUESDAY WITH SNOW POSSIBLE AT HIGHER ELEVATIONS AND A SLIGHT CHANCE OF THUNDERSTORMS. TEMPERATURES WILL AVERAGE SLIGHTLY BELOW NORMAL NEXT WEEK. ...DISCUSSION... AREAS OF LOW CLOUDS REMAINED THIS AFTERNOON...ESPECIALLY IN A BAND FROM ABOUT 10-30 MILES INLAND FROM THE COAST. PRETTY GOOD CLEARING OCCURRED NEAR THE COAST DUE TO THE GREATER STABILITY THERE. THE SLIGHT LOWERING OF THE INVERSION...AS SEEN ON ACARS...HELPED THE MOUNTAINS TO MOSTLY CLEAR OUT. A STRONG EDDY WAS WEST OF CATALINA ISLAND.

WE WILL LIKELY CLEAR THE LOW CLOUDS BETTER ON SUNDAY AS THE MODELS HAVE LOWER RH VALUES AT AND BELOW 850 MB THAN FOR TODAY. THE ONSHORE FLOW SHOULD BE A BIT WEAKER TOO...ESPECIALLY WITH REGARDS TO UPSLOPE OROGRAPHICS WHICH REALLY KEEP THE MARINE LAYER INTACT. THE EDDY IS EXPECTED TO WEAKEN SOMEWHAT AS LARGE SCALE SOUTHERLY FLOW MOVES INTO THE OUTER WATERS...IN FACT...WINDS ARE ALREADY GENERALLY WEAK OUT NEAR PT CONCEPTION.

THE STORM SYSTEM IS STILL EXPECTED MONDAY INTO TUESDAY...WITH TIMING SLIGHTLY LAYER IN THE CURRENT PROGS THAN 24 HOURS AGO. THE EXCEPTION IS WITH NOGAPS...BUT THAT MODEL WILL BE IGNORED FOR NOW AS IT IS THE OUTLIER. RIGHT NOW...THE ONSET OF THE PRECIP LOOKS LIKE MONDAY FROM NW TO SE...WITH S AND E PORTIONS POSSIBLY DELAYING UNTIL MONDAY NIGHT. GOOD DIGGING IS ALREADY OCCURRING WITH THE CENTER OF COLD AIR NEAR 40/138W WITH HIGH CLOUDS ALREADY AS CLOSE AS POINT CONCEPTION...SO THIS STORM LOOKS PRETTY LIKELY.

TSTORMS WILL BE A POSSIBILITY...ESPECIALLY UP NORTH WITH 500 MB TEMPS BELOW -20C...AND -25C FLIRTING WITH OUR NORTHERN AREAS AND OF COURSE THE VIGOROUS DYNAMICS. OMEGA VALUES LOOK STRONGLY UPWARD AT 700 MB...ESPECIALLY MONDAY NIGHT. THE SNOW LEVEL WILL LIKELY START AROUND 7000 FEET MONDAY...BUT DECREASE TO AS LOW AS 5000 FEET TUESDAY. STRONG SW WINDS AT 700 MB AHEAD OF THE STORM WILL AFFECT THE MTNS AND LOCATIONS DOWNWIND OVER THE DESERTS.

WED/THU LOOK KIND OF PARTLY CLOUDY AND A BIT COOL AS WEAK TROUGHING DEVELOPS BEHIND THE MAIN STORM. THE TROUGHING LOOKS A BIT TOO WEAK FOR PRECIP SO FAR THEN...BUT THAT COULD CHANGE.

SAN 00-5

.SAN...SPS FOR MON-TUE STORM.

MAXWELL



AT 06Z SHALLOW CDFNT WAS MOVG SLOWLY SE ACRS FAR NRN INDIANA AND NW OH. COLD AMS ONLY EXTENDED UP TO ABT 2K FT ON RECENT ACARS SOUNDING OUT OF ORD. MODELS SIMILAR IN HANDLING OF FRONT...SUGGESTING IT WILL BE NEARLY STNRY E-W ACRS CENTRAL PORTION OF CWA TDY. SOME LOW CLOUDS WERE MOVING SOUTH FROM SRN LM INTO NW IND...BUT LOW CLOUDS OVR NRN/CNTRL MI MAKING LTL SOUTHWARD PROGRESS. WITH FRONT BECOMING STNRY, XPCG SOLID STRATUS DECK TO STAY TO OUR N AND NW OF CWA DEEPER IN COLDER AMS AND DOWNWIND OF LM. WITH LESS CLOUDS THAN INDICATED BY SBN FWC WL RAISE FWC MAX TEMP FCST FOR TDY. ETA SOUNDINGS INDICATE COLD AIR WL MIX OUT AT SBN TODAY WITH HIGHS REACHING AROUND 70. WITH FRONT EXPECTED TO REMAIN TO THE SOUTH, THINK SOME LOW LVL INVERSION WL REMAIN, SO WL NOT GO QUITE THAT WARM NORTH OF FRONT, BUT ETA 2M TEMPS LOOK REASONABLE SOUTH OF FRONT.

COUPLE FACTORS SUPPORT LEAVING POPS IN FOR THIS AFTN. STG S/WV OVR SRN PLAINS MOVG EAST IS PROGGED TO REACH MID MS VLY BY 00Z. STRENGTHENING WIND FIELDS OVR STNRY FRONT WL INCRS ISENT LIFT OVR NWRN PORTIONS OF CWA THIS AFTN. OVR REST OF AREA CAPE WILL INCREASE TO ARND 1000 WITH DECENT LOW LVL MOISTURE CONVERGENCE ALONG SNTRY FRONT. CONVECTION COVERAGE SHD BE LIMITED AS DEEP MOISTURE LACKING IN THIS AREA.

WARM, MOIST, UNSTABLE AIR WL OVERUN STNRY FRONT TNGT AS STG APPROACHES CWA...WL GO WITH CATAGORICAL POPS WITH MENTION OF TSTMS. SOME SHOWERS LIKELY TO LINGER INTO MONDAY AS S/WV MOVES ACRS THE AREA WITH DEEP MOISTURE REMAINING IN PLACE. RAIN SHD COOL THINGS OFF TNGT AND RESULT IN FRONT SAGGING SOUTH A BIT. PLENTY OF CLOUDS REMAINING MON SHD KEEP TEMP RECOVERY TO A MINIMUM...FWC'S FOLLOWED. .IWX...NONE

DJT