Forecast Discussions mentioning ACARS, received at FSL on 05/05/01

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
AFDLOX 925 PM PDT FRI MAY 4 2001

ANOTHER QUIET EVENING ACROSS THE DISTRICT. MARINE INVERSION QUITE SHALLOW WITH 00Z VBG SOUNDING SHOWING DEPTH AROUND 800 FEET...AND ACARS SOUNDINGS SHOWING DEPTH OVER LAX/LGB AT OR BELOW THIS LEVEL. GOOD ACARS TEMP/DEWPOINT SOUNDING AT LAX SHOWS ATMOS VERY DRY DOWN TO LOW LEVELS. DIFFICULT TO SAY IF AND WHEN MARINE LAYER CLOUDS WILL FORM OVERNIGHT. MESO-ETA RH IN THE CROSS SECTIONS SHOW THERE MAY BE ONLY PATCHY LOW CLOUDS AT BEST ALONG THE LAX COUNTY COAST LATER TONIGHT. WILL UPDATE ZONES TO CHANGE AREAS OF LOW CLOUDS TO PATCHY LAX/VTU COUNTIES...AND TAKE OUT LOW CLOUDS FROM VTU/LAX VALLEYS. LOOK FOR ZONE UPDATE BY 945 PM.

UPPER HI OFF W COAST FORECAST TO BUILD SLOWLY EAST TO A POSITION TO JUST OFF THE CA COAST SUN. GRADIENTS WILL BE ONSHORE AFTERNOONS AND EVENINGS...THEN LIGHT ONSHORE TO NEUTRAL MORNINGS. TEMPS WILL BE NEAR OR ABOVE SEASONAL LEVELS INLAND...AND NEAR NORMAL ALONG THE COAST. MARINE LAYER SHOULD BECOME BETTER ESTABLISHED ALONG THE COAST SAT NIGHT INTO SUN MORNING...BUT MARINE LAYER SHOULD BE SHALLOW AND SHOULD AFFECT COASTAL SECTIONS FOR THE MOST PART WITH ONLY MINIMAL INLAND PENETRATION.

IN THE EXTENDED...UPPER HIGH BUILDS RIGHT OVER CA MON AND TUE THEN MOVES SLOWLY EAST FOR WED. DRY WEATHER TO CONTINUE OVER THE DISTRICT WITH TEMPS ABOVE NORMAL MOST AREAS EXCEPT NEAR NORMAL ALONG THE COAST AS ONSHORE DAYTIME FLOW CONTINUES.

LAX 0000. SIRARD.

.LAX...NONE.



AREA FORECAST DISCUSSION
NWS CHICAGO IL
AFDCHI 330 AM CDT SAT MAY 5 2001

A BAND OF PRECIPITATION AS LIES FROM PONTIAC ILLINOIS TO RENSSALEAR INDIANA. THIS IS A RESULT OF OVERRUNNING NORTH OF THE SURFACE FRONT. A DETAILED LOOK AT THE IR LOOPS SHOWS A SHORT WAVE MOVING NORTH TOWARDS NORTHEAST ILLINOIS AND NORTHWEST INDIANA. HOWEVER IS APPEARS TO BE VERY WEAK. WILL KEEP SOME POPS OVER THE SOUTHERN PARTS OF OUR FORECAST AREA TODAY. THIS WILL BE THE SOUTHERN EDGE OF THE TEMPERATURE GRADIENT AT 850 MB AND SURFACE. THE ACARS SOUNDINGS OVER ORD AND RFD SHOW INVERSIONS WITH THE INVERSION AT ORD BEING STRONGER. THESE INVERSION WILL SUPPRESS ANY MAJOR PRECIPITATION. THERE MAY BE SCATTERED SPRINKLES OF RAIN AT BEST.

FOR THE REST OF THE AREA WILL KEEP THE PRECIPITATION FOR SATURDAY NIGHT. POSITIVE VORTICITY ADVECTION AT 700 TO 300 MB IS SEEN MOVING INTO THE AREA LATE. ISENTROPIC AND TEMPERATURE FORECASTS FROM THE AVN AND ETA MODELS SHOW THE WARM FRONT MOVING INTO THE REGION SUNDAY. WILL KEEP THE CURRENT TREND IN THE TEMPERATURES FORECASTS.

.CHI...NONE $$ WHW