Forecast Discussions mentioning ACARS, received at FSL on 01/05/00




AREA FORECAST DISCUSSION

NWS CHICAGO IL

AFDCHI 236 AM CST WED JAN 5 2000

06Z SFC ANALYSIS PLACES RDG AXIS RIGHT UP THE MISSISSIPPI RVR VLY. 
GOES 11-3.9 MICRON LOOP SHOWING LO SC DECK ADVECTING EAST AHEAD OF 
THE RDG...WITH RAGGED CLRG LINE FM WEST OF MKE SOUTH TO DEC AND PAH. 
FLURRIES HAVE HUNG TOUGH ACROSS NERN IL UP UNTIL NOW AS LOW LVL 
CONVERGENCE BETWEEN WESTERLY FLOW OVR NRN IL AND NW FLOW COMING DOWN 
LAKE MICHIGAN...HAS BEEN SUFFICIENT TO SQUEEZE OUT SOME LGT PCPN. 
ALSO AIDING IN FLURRY DEVELOPENT...07Z ORD ACARS SOUNDING ALSO SHOWS 
RELATIVELY STEEP LO LVL LAPSE RATE THROUGH THE SHALLOW SC LAYER...UP 
TO AROUND 4500 FT. IMPRESSIVE H5 12 HR HEIGHT RISES OVR MIDWEST AND 
RESULTING ADVANCEMENT OF SFC RDG SHOULD CLEAR OUT THE CLOUDS AND 
FLURRIES SHORTLY.

ATTENTION THEN TURNS TO NEXT APPROACHING CLIPPER LIKE S/WV IN 
PROGRESSIVE PTN. S/WV CURRENTLY DROPPING INTO THE NORTHERN 
PLAINS...WITH SFC LO JUST N OF THE MONTANA/N DAK BORDER. HIGH CLOUDS 
IN ADVANCE OF THIS SYSTEM ALREADY SPILLING OVR THE UPR RDG AND 
SPREADING INTO THE WESTERN GRT LKS...SO INCRSG CLOUD FCST FOR TDY ON 
TRACK. MODELS ARE CONSISTENT IN MOVING SEVERAL VORTS THROUGH THE 
TROF AS IT PASSES TO OUR NORTH NXT 48 HRS. UPSTREAM SOUNDINGS 
RELATIVELY DRY...AND WITH BEST ORGANIZED LIFT PASSING TO OUR NORTH 
LOOKS LIKE ONLY CHC POPS OF SOME LIGHT SNOW/FLURRIES LATER TONIGHT 
AND THURSDAY. BETTER CHC STILL LOOKS TO BE THURSDAY NIGHT/EARLY 
FRIDAY...AS SECOND STRONGER VORT DROPS SOUTHEAST ACROSS MN AND NE IA 
WITH DECENT TROF REFLECTED AT THE SFC. FAN POPS LOOK A LITTLE TOO 
HIGH INITIALLY GIVEN NORTHERN TRACK OF SFC LOW AND DRY AIR...AND 
FAVOR LOWER FWC NOS. PREFER FAN POPS IN THE LIKELY RANGE FOR SECOND 
SYSTEM THURSDAY NGT. CURRENT ZFP HAS THESE TRENDS WELL IN HAND.

TEMP WISE...FAN/FWC GUIDANCE ARE WITHIN A DEGREE OF EACH OTHER THRU 
THE PD...AND WILL CONT TO FOLLOW. ALL IN ALL...NO SIG CHGS TO GOING 
FCST.

.CHI...NONE.

RATZER

AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
AFDFWA 330 AM EST WED JAN 5 2000

H85 THERMAL TROF MOVG ACRS LM EARLY THIS MORNING. ACARS INDICATING MODELS TOO WARM IN LOW LVLS WITH COLDER ETA DOING THE BEST. PROFILER NETWORK AND LAMP SFC ANALYSIS SHOW LOW LVL RDG MOVG EAST INTO IL/WI ATTM...SHD MOVE ACRS AREA BTWN 12-18Z BRINGING LAKE EFFECT TO AN END. LTL ADTNL ACCUM THIS MORNING AS 1000-700 MB SHEAR INCREASES AND INVERSION LOWERS.

MODELS IN DECENT AGREEMENT THAT UPR LVL TROF OVR WRN GRTLKS WL MOVE QUICKLY TO THE EAST TODAY, WITH NEW TROF DROPPING SE FM ALBERTA/MT AND STRENGTHENING AS IT MOVES INTO THE UPR MDWST BY THU EVE. AT SFC, LOW XPCD TO MOVE EAST ALONG U.S./CANADIAN BORDER TO SRN ONTARIO BY THU EVE WITH CDFNT MOVG ACRS CWA THU. AVN SLOWER WITH MOVEMENT OF SFC LOW AND FRONT WHICH SEEMS REASONABLE GIVEN DIGGING UPR TROF. SHD TURN COLD ENUF BEHIND THIS FRONT FOR LAKE EFFECT SNOW TO DVLP, BUT, GOING WITH SLOWER AVN, XPC LAKE EFFECT ACCUMS TO HOLD OFF UNTIL THU NGT/FRI WHEN H5 TROF MOVES THRU THE AREA.

LOW CLOUD DECK OVR IL/WI MAKING SLOW PROGRESS EAST ATTM. NGM LOOKS TO BE HANDLING THE LOW LVL MOISTURE BEST AND INDICATES BACK EDGE OF LOW CLOUDS WL MOVE SLOWLY EAST ACRS THE AREA TODAY. HWVR, LOW LVL WAA RESULTING IN MID/HI CLDS OVR UPR MS VLY WHICH WILL BE SPREADING ACRS NRN PORTIONS OF THE AREA TODAY AND THE REST OF THE AREA TONIGHT. WL GO WITH MOSTLY CLOUDY EVERYWHERE TODAY, EXCEPT MONTICELLO-PERU AREA WHERE BECMG PARTLY SUNNY SHD DO. SMALL ETA QPF IN THE WAA AHD OF FRONT TNGT SEEMS UNLIKELY GIVEN DRY AMS AND WK UVM. PREFER AVN SOLUTION AND CHC FAN POPS ALONG/BEHIND FRONT THU.

MOS TEMPS RUNNING A LTL TOO COLD AT SBN THIS MORNING DUE TO FLOW OFF LM. HWVR, NOT MUCH RISE EXPECTED TODAY AS LOW LVL AMS QUITE COLD WITH LGT FLOW BENEATH SFC RDG MOVG INTO AREA. LTL TEMP FALL TNGT AS SW GRADIENT INCREASES ACRS THE AREA. TEMPS SHD BOTTOM OUT EARLY, ESCPLY WEST.

.IWX...NONE JT