Forecast Discussions mentioning ACARS, received at FSL on 03/01/00

SHORT TERM DISCUSSION: SKIES SHOULD BE NEARLY CLEAR OVERNIGHT... THOUGH SOME CI MAY START TO MOVE IN LATE. PRESSURE GRADIENT WILL BE FLAT GOING TO LIGHT SOUTHERLY SO ONLY LIGHT DRAINAGE WINDS ARE EXPECTED. TEMPERATURES HAVE WARMED A BIT MORE THAN EXPECTED TODAY...BUT I WILL STILL UNDERCUT GUIDANCE LOWS A BIT. GIMMESTAD LONG TERM DISCUSSION: ANOTHER SYSTEM MISSES THE FRONT RANGE LEAVING US ZERO FOR THE LAST TWO AS WE PUT OUR SPRINGLIKE FEB TO REST. A NUMBER OF CHANCES FOR PCPN IN THE NEXT 10 DAYS AS SYSTEMS MOVE RAPIDLY ACRS THE PACIFIC INTO THE WRN US WITH AN ANCHORED MEAN TROF IN THE NORTH PACIFIC. QUESTION IS NOW THAT MARCH IS HERE CAN WE PUT ALL THOSE FEB MISSES BEHIND US AND GET OUR REAL WINTER GOING. THE ANSWER IN THE SHORT TERM IS BY NO MEANS CERTAIN AS THE NEXT EVENT HOLDS A NUMBER OF QUESTIONS FOR THURSDAY. THE SYSTEM IS ON THE W COAST ATTM WITH A NRN PORTION ROTATING INTO THE PAC NW AND A SRN PTN DRIVING TWDS SRN CALIF ON THE STRENGTH OF A 120KT PLUS JET ON ITS BACKSIDE. COMPARISON OF THE MODEL FCSTS INDICATES THE MAIN DIFFERENCE IS THE ETA DROPS THE SYSTEM FARTHEST SOUTH BY 12Z THU WITH A CLOSED LOW IN CTRL NM AND LITTLE IN THE WAY OF UPSLOPE OR FORCING FM DEN NORTH. AVN TRENDING FARTHER S AS WELL WITH GREATER THREAT OF SIG PCPN FOR SERN CO BUT STILL ENUF FOR UPSLOPE AND CHC OF SNOW OUR AREA...VS PROBABLY A MISS ON THE ETA. INITIAL ANALYSES INDC ETA HAS A STRONGER JET ON THE W SIDE OF THE SYSTEM THAN THE OTHER TWO MODELS BUT NO OBS TO TELL WHICH IS CORRECT. NOT SURE IF RUC ANALYSES HAVE ENUF ACARS TO KNOW STRUCTURE OF THE JET OFF CALIF COAST...BUT 6H ETA FCST DOES MATCH UP BETTER THAN OTHER MODELS IN TERMS OF JET. ON THE OTHER HAND LATER CUTOFF FOR AVN/NGM VS ETA MIGHT MEAN BETTER DATA UPSTREAM SO REALLY LEFT WITH NO REASON TO NECESSARILY BELIEVE MORE SRN ETA TRACK OVR AVN/NGM FOR UPR LVL SYSTEM. AHEAD OF THE SYSTEM HI PRES WILL PUSH S OVNGT AND SET UP RETURN FLOW ON WED...TOO BAD THE HI ISN'T TIMED FOR THU IN WCH CASE WUD HAVE MORE CONFIDENCE IN SNOW FOR NERN CO. WITH RETURN FLOW WED LUK FOR A MILD DAY AND LIKELY DENVER CYCLONE SETTING UP. DWPNTS WILL TAKE AWHILE TO BUILD UP BUT WITH INCRS IN UPR LVL FORCING LATE IN THE DAY WILL PUT SOME CHC OF RAIN SHOWERS ON THE PLAINS BY LATE AFTN. RAIN/SNOW WILL BE AN ISSUE AGAIN FOR WED NIGHT BUT SHOULD WE ACTUALLY GET A DEEP MOIST UPSLOPE LIKE THE AVN SHOWS THEN IT SHOULD BE COLD ENUF FOR SNOW ON THE PLAINS ON THU. IF THE SYSTEM DOES HOWEVER GO FARTHER S THEN NOT ONLY WILL CHC OF PCPN GO DOWN BUT THREAT OF RAIN SHWRS INSTEAD OF SNOW WILL BE A REAL POSSIBILITY. LOTS OF UNCERTAINTY...ATTM DOES NOT LUK LIKE A BIG EVENT FOR THE NE BECAUSE OF THE MORE SRN TRACK...A SYSTEM THAT ISN'T TERRIBLY POTENT...AND AN ILL-TIMED HI PRES SYSTEM FROM THE NORTH. STILL...IF THE UPR LO IS FURTHER N AND TAKES A NE TURN AS IN THE AVN FCST FOR THU...THEN NERN CO CUD STILL GET A DECENT EVENT OUT OF THIS. FOR NOW WILL KEEP THINGS IFFY WITH BETTER CHC OF PCPN FARTHER E. NOT AN ESPECIALLY FAVORABLE FLOW FOR THE MTNS AND ATTM MAY GET THRU EVENT WITHOUT NEED TO HOIST ANY MTN HILITES.

LONGER TERM THE MRF APPEARED TO BE TOO FAST W NEXT SYSTEM WHEN COMPARED WITH THE CAN..UK AND EC WCH WITH THEIR SLOWER MVMNT WUD KEEP SAT MAINLY DRY. HOWEVER NEW AVN AND CANADIAN 72H AGREES EXACTLY WITH SPEED OF MRF...SO WENT AND PUT SOME PCPN IN FOR SAT. HOWEVER THIS NEXT SYSTEM ATTM DOES NOT LUK WELL ORGANIZED SO WILL WORD AS SLGT CHC FOR THE PLAINS AND HAVE RAIN OR SNOW PSBLTIES. SZOKE

.DEN...NONE.

...SYNOPSIS... A WEAKENING COLD FRONT IS MOVING ACROSS SOUTHWEST CALIFORNIA TONIGHT. LIGHT RAIN IS OCCURRING AHEAD OF AND ALONG THE FRONT. BEHIND THE FRONT A FEW SHOWERS ARE POSSIBLE WITH THE SNOW LEVEL DROPPING TO 4500 FEET. GUSTY WEST TO NORTHWEST WINDS ARE ALSO EXPECTED. THESE CONDITIONS WILL PERSIST INTO WEDNESDAY MORNING. A SERIES OF FAST MOVING PACIFIC STORMS WILL CONTINUE TO AFFECT CALIFORNIA THROUGH THE COMING WEEKEND. THE NEXT STORM SHOULD BRING RAIN...WITH SNOW IN THE MOUNTAINS...LATE THURSDAY AFTERNOON THROUGH FRIDAY. THE STORM BEHIND THAT IS EXPECTED TO REACH THE AREA SUNDAY. IN BETWEEN THESE STORMS...BEAUTIFUL SPRING LIKE CONDITIONS WILL PREVAIL.

...DISCUSSION... UPSTREAM SOUNDINGS AND ACARS SUPPORT SNOW LEVEL LOWERING TO 4500 FEET BEHIND FRONT. NORTHWEST 75-95KT WINDS AT 400 MB...WEST 50 KTS AT 10000 FT AND WEST 30KT AT 8000 FT ALSO SUPPORT GUSTY WIND FORECASTS FOR THE MOUNTAINS AND HIGHER DESERTS/VALLEYS. SO FAR GUSTS AT RELIABLE RAWS STATIONS DO NOT WARRANT WIND ADVISORIES AND EXPECTED FORMATION OF NOCTURNAL INVERSION SHOULD KEEP LEE SIDE MOUNTAIN WAVES FROM SURFACING. AS FAR AS PRECIPITATION THREAT...ONLY LIGHT SHOWERS BEING REPORTED ALONG FRONT AND SO FAR ONLY ISOLATED ISLAND EFFECT/OROGRAPHIC LIFTING GENERATING SHOWERS BEHIND THE FRONT SO 20 PERCENT POPS FOR LOWER ELEVATIONS AND 30-50 PERCENT POPS FOR MOUNTAINS STILL OKAY. MOST OF THE CONVECTION HAS BEEN OVER THE NORTHERN DESERTS AND SACRAMENTO VALLEY WHERE STRONGEST COLD AIR ADVECTION...ABOUT 18 DEGREES FAHRENHEIT COOLING PAST 24 HOURS IN THE MID AND UPPER LEVELS....HAS DESTABILIZED AIR MASS. FOR SOUTHERN CALIFORNIA THIS WAS OUT OF PHASE/TOO LATE TO ENHANCE DIURNAL HEATING TODAY..AND SUBSIDENCE/WARMING ALOFT WILL DOMINATE WEDNESDAY...SO SLIGHT CHANCE OF SHOWERS TONIGHT/WEDNESDAY MORNING ALSO LOOKS GOOD.

THE 01/00Z RUN OF AVN STILL SUPPORTS CURRENT FORECAST TIMING/INTENSITY OF NEXT SYSTEM THURSDAY AFTERNOON THROUGH FRIDAY. NO REASON TO CHANGE EXTENDED FORECAST. MARINE OUTLOOK ALSO LOOKS GOOD MENTIONING INCREASING SEAS AS STRONG FETCH ACROSS PACIFIC CONTINUES TO GENERATE MASSIVE SEAS...YIELDING A MODERATE TO LARGE WEST SWELL FOR S CALIFORNIA.

SAN 2202

.SAN...NONE ATTM...MAY NEED SCA WEDNESDAY FOR WINDS.

BALFOUR