Forecast Discussions mentioning ACARS, received at FSL on 04/21/00

...MAIN FORECAST PROBLEMS ARE STRONG WINDS AND PRECIPITATION TYPE IN THE FIRST PERIOD OF FORECAST...

LATEST SATELLITE SHOWS DEFORMATION ZONE PIVOTING FROM EAST-WEST TO A MORE NORTH-SOUTH ORIENTATION OVER FORECAST AREA AND MOVING VERY SLOWLY. RADAR INDICATED WIDESPREAD PRECIPITATION WITH CONVECTIVE LOOKING PRECIPITATION DEVELOPING ON SOUTHERN PERIFERY OF PRECIPITATION AREA OVER CENTRAL AND EAST CENTRAL COUNTIES. SNOW OR A MIXTURE OF RAIN AND SNOW HAS BEEN FALLING ACROSS THE NORTH CENTRAL COUNTIES...WITH LOCALIZED ACCUMULATIONS OF 1 TO 2 INCHES BETWEEN RHINELANDER AND EAGLE RIVER. PRESSURE GRADIENT CONTINUES TO INCREASE AS SURFACE LOW TRACKS OVER CHICAGO INTO SOUTHERN LAKE MICHIGAN AND SURFACE HIGH PRESSURE HOLDS ITS POSITION OVER SOUTHERN EDGE OF HUDSON BAY.

WIND ADVISORY WILL BE CONTINUED AS PRESSURE GRADIENT REMAINS VERY STRONG THROUGH THE EVENING HOURS AND EVEN A LITTLE PAST MIDNIGHT. WIND OBSERVATIONS IN MENOMINEE MICHIGAN SHOWING GUSTS TO 50 MPH. WILL EXTEND WIND ADVISORY TO COVER AREAS OF MARINETTE AND OCONTO COUNTIES NEAR THE BAY.

INVESTIGATION OF ACARS DATA INDICATES DYNAMIC COOLING CONTINUING TO OCCUR UNDERNEATH AXIS OF UPPER TROUGH. ETA AND NGM SURFACE...925 AND 850 MB TEMPERATURES WHICH MATCH THE RAIN SNOW LINE...ARE FORECAST BY THE MODELS TO GRADUALLY SINK SOUTHEAST INTO THE EAST CENTRAL PART OF THE STATE LATE THIS EVENING. ETA AND NGM TIME SECTIONS SHOW DEEP HIGH RELATIVE HUMIDITIES AND LIFT EXTENDING THROUGH MOST OF EVENING ACROSS NORTHWEST HALF OF FORECAST AREA AND BEYOND MIDNIGHT ACROSS SOUTHEAST HALF. DEFORMATION ZONE ON SATELLITE MOVING LITTLE SO PRECIPITATION MAY LAST EVEN LONGER THAN THAT. WITH COOLING PARAMETERS ALREADY MENTIONED...SHOULD MIX WITH OR CHANGE TO SNOW BEFORE ENDING ACROSS MUCH OF THE FORECAST AREA. SEVERAL INCHES OF ADDITIONAL ACCUMULATION EXPECTED IN NORTH CENTRAL COUNTIES...WITH A LIGHT SLUSHY ACCUMULATION POSSIBLE ANYWHERE ELSE THAT CHANGES TO SNOW.

USED A BLEND OF FWC/FAN GUIDANCE.

.GRB...WIND ADVISORY TONIGHT FOR EAST CENTRAL AND EXTREME NORTHEAST WISCONSIN. WIZ013-021-022-038>040-048>050

KENNEDY WWW.CRH.NOAA.GOV/GRB



SATELLITE IMAGERY SHOWING SUBSTANTIAL LOW AND MID LEVEL CLOUDS MOVING INTO CWA THIS MORNING. SURFACE OBSERVATIONS ALSO INDICATING SIGNIFICANT LOW LEVEL SOUTHEAST FLOW...HELPING TO USHER IN SOME LOW LEVEL MOISTURE THIS MORNING...AND DEEPENING THE MARINE LAYER RAPIDLY.

12Z SOUNDINGS AND LATEST ACARS SOUNDINGS DEPICTING SOUTH TO SOUTHEAST FLOW ALOFT. WATER VAPOR IMAGERY SHOWING UPPER LOW MOVING A TAD SLOWER THAN 12Z ETA/AVN SOLUTIONS. THIS WILL RESULT IN SOUTHERN CALIFORNIA REMAINING IN FAVORABLE NORTHEAST QUADRANT OF UPPER LOW THROUGH THE AFTERNOON...DURING PEAK HEATING HOURS. MSAS LIFTED INDEX ANALYSIS ALREADY SHOWING LIFTED INDICES NEAR ZERO ACROSS THE LA BASIN...WHICH IS THEN PROGGED TO GO UNSTABLE THIS AFTERNOON...AS ATMOSPHERE WARMS IN LOWER LEVELS AND COLD POOL ALOFT APPROACHES THE AREA.

UPPER LEVEL LOW PROGGED TO MOVE INLAND LATER TONIGHT AND SATURDAY... LEADING TO A DRYING TREND FOR ALL AREAS AND BREEZY CONDITIONS FOR MOUNTAINS AND DESERTS. CURRENT POPS AND TEMPERATURES LOOK ON TRACK FOR NOW...SO NO UPDATES PLANNED FOR THE MOMENT.

LAX 440. BRUNO.

.LAX...SMALL CRAFT ADVISORY...SEE LACWFLAX.