Forecast Discussions mentioning ACARS, received at FSL on 03/26/01

...SYNOPSIS...

A DEVELOPING COASTAL EDDY AND A DEEPENING MARINE LAYER WILL SPREAD CLOUDS AND AREAS OF DRIZZLE INTO COASTAL AND INLAND AREAS TONIGHT AND MONDAY. A DEEP MARINE LAYER WILL KEEP CLOUDS LINGERING EACH AFTERNOON THROUGH TUESDAY...ALTHOUGH SOME CLEARING IS POSSIBLE TUESDAY AFTERNOON. ON WEDNESDAY AND THURSDAY...BUILDING HIGH PRESSURE AND WEAK OFFSHORE FLOW WILL BRING WARMER WEATHER.

...DISCUSSION...

SKIES CLEARED THIS AFTERNOON OVER MOST OF THE CWA EXCEPT FOR ORANGE COUNTY WHERE STUBBORN LOW CLOUDS LINGERED. ACARS SOUNDINGS SHOWED THE MARINE LAYER IS STILL AROUND 3000 FEET DEEP.

A SERIES OF WEAK SHORTWAVES MAINTAIN TROFINESS OVER SOCAL THROUGH TUESDAY MORNING. THE MESOETA LOW LEVEL WIND FIELD DEVELOPS AN EDDY OVERNIGHT WITH CLOUDS ONCE AGAIN SPREADING INLAND TO THE MOUNTAIN SLOPES. COMBINED EFFECTS OF EDDY AND STRONG ONSHORE GRADIENTS MAY PRODUCE DRIZZLE LATE TONIGHT AND MONDAY MORNING...WITH ONLY PARTIAL AFTERNOON CLEARING IN SOME AREAS DUE TO THE DEEP MARINE LAYER.

ON TUESDAY...THE UPPER LEVEL WINDS SHIFT NORTHERLY IN RESPONSE TO WEAK RIDGING IN THE AFTERNOON. WEAK OFFSHORE NORTHERLY GRADIENTS WILL BRING A BETTER CHANCE FOR CLEARING IN SBD AND RIV COUNTIES TUESDAY AFTERNOON...POSSIBLY REACHING INTO ORANGE COUNTY. IN SAN DIEGO COUNTY THE GRADIENTS REMAIN PREDOMINANTLY ONSHORE TO THE EAST AND CLEARING WILL BE SLOWER.

IN THE EXTENDED...UPPER RIDGE BUILDS OVER THE WESTERN STATES WEDNESDAY THROUGH FRIDAY FOR WARMER WEATHER AND MORE SUN...ALTHOUGH THE MARINE LAYER WILL MAKE AN APPEARANCE EACH MORNING TO SOME DEGREE. BEYOND FRIDAY THE MODELS DIVERGE RATHER SIGNIFICANTLY WITH THE MRF BRINGING A VIGOROUS SHORTWAVE ACROSS SOCAL...THE ECMWF BRINGS A BROAD TROF INTO NORCAL...AND THE NOGAPS BUILDS A RIDGE OFF THE COAST OF CA. FOR NOW...WILL MAINTAIN DRY FORECAST THROUGH NEXT WEEKEND WITH MINOR VARIATIONS IN TEMPS AND MARINE LAYER CLOUDS.

SAN 000

.SAN...MARINE WEATHER STATEMENT...SEE LAXMWSSAN.

MOEDE



THE 500 MB WAVE WILL MOVE EAST THROUGH THE 36 HOURS. THERE IS A NEAR ADIABATIC LAPSE RATE BELOW 800 MB SEEN ON THE ILX AND ACARS AT ORD SOUNDINGS. AS THE WAVE SWINGS AROUND TODAY AND TONIGHT SNOW SHOWERS OCCURS AIDED BY THE LOW LEVEL INSTABILITY. THESE SHOWERS WILL GRADUALLY DIMINISH TONIGHT. WILL MENTION FLURRIES TONIGHT.

A RIDGE AT 500 MB MOVES INTO NORTHEAST ILLINOIS AND NORTHWEST INDIANA AT 54 TO 60 HOURS FROM THIS MORNING. WARMER TEMPERATURES ARE INDICATED BY THE AVN MOS AND ETA SURFACE TEMPERATURE FORECASTS. A SHORT WAVE APPROACHES ON WEDNESDAY AND WITH INCREASE RELATIVE HUMIDITY AND FORECASTS LIFT BY BOTH THE ETA AND AVN WILL ADD A CHANCE OF SHOWERS ON WEDNESDAY. .CHI...NONE $$ WHW



MINOR UPDATES SE OREGON AND W PARTS OF SW IDAHO FOR SCT SHOWERS ISOL VLY FOG IN ADVANCE OF NEXT SYSTEM OVER E OREGON.

TREASURE VALLEY WINDS SHIFTED SE ENHANCING LOW LAYER CONVERGENCE INTO NEXT MOIST SYSTEM OVER ERN OREGON THIS EVENING. SCT SHOWERS IN NRN MALHEUR CO INTO BAKER AND WASHINGTON COUNTIES AS WELL. AP ON LOWEST ELEV AND CR PRODUCT AGAIN TONIGHT FROM NAMPA TOWARD NYSSA-ADRIAN AND ALONG BENNETT MTNS SHOWING SFC STABILIZING WITH FOG FORMING IN MYL WITH EVENING VALLEY STABILIZATION. SWATH OF SHOWERS IN ERN OREGON TO MOVE OUT OF ERN ORE LATER TONIGHT AND BE CENTERED OVER SW IDAHO ABOUT 6AM. THEN CONTINUE MOVING E WHILE WEAKENING AS SFC HIGH PRES BUILDS OVER ORE TODAY. UPPER TROF OVER NW WASH MOVING ACROSS N-CNTRL ID BY MID DAY TO KEEP CLOUDS IN MTNS TODAY BUT ALLOW LOTS OF AFTERNOON SUNSHINE SOUTHERN VALLEYS AND S MTNS AND ACROSS SE OREGON. SFC GRADIENT WITH BUILDING HIGH IN 00Z RUNS NOT NEARLY AS STRONG AS 12Z RUNS ADVERTISED. PRES RISES BEHIND FRONT AREA BARELY OVER 1MB/3HR INDICATING NOT AS STRONG A FRONT/BUILDING HIGH PRES. WILL WAIT FOR 6Z BUOYS AND MTR PRES CHANGES BEFORE HAULING THE CURRENT FORECAST 15-25/20-30 MPH WINDS DOWN TO AROUND 15 FOR TREASURE VALLEY AND 20 FOR MAGIC VALLEY. LITTLE MORE GRADIENT REMAINS IN SE OREGON DUE TO STRONGER LOW OVER N CALIF, FOR NORTH WINDS 10-20 MPH. ADVANCING HIGH CLOUDS TUESDAY BUT MILDER. BY TUESDAY EVENING RAIN LIKELY OVER SE OREGON LOOKS RIGHT ON TRACK WITH CURRENT PACKAGE PER CURRENT SATL/MODEL TRENDS. QUICK MOVEMENT SHIFTS SYSTEM THROUGH SW IDAHO BY EARLY WEDNESDAY MORNING WITH SINKING ACROSS SE OREGON WED. MORNING.

NO CHANGES EXCEPT FIRST PERIOD BUT MAY NEED TO BACK OFF ON MONDAY WINDS. UPDATE...ACARS DATA FOR BOISE/PORTLAND SHOW LOW LAYER WINDS ONLY UP TO 20 KTS WITH TEMPERATURE DIFFS ACROSS THE FRONT MEAGER (4C@500/2.5C@700) SO AM INCLINED TO UPDATE MONDAY/2ND PERIOD AS WELL.

.BOI...NONE. MILLS