000 
FXUS63 KILX 012036
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1025 AM CST THU JAN 1 2004

.DISCUSSION...
MODELS VERY SIMILAR IN OUR CWA THROUGH 36 HRS. THEN THEY BEGIN TO 
DIVERGE...WITH HOW FAR SOUTH FRONT GOES ON SAT 12Z. ETA CONTINUES TO 
BE FURTHEST SOUTH AND HAS TRENDED FURTHER THAN PREV RUN. THE GFS HAS 
TRENEDED FURTHERN SOUTH...BUT NOT MUCH. CANADIAN...UKMET AND ECMWF 
ALL SIMILAR TO ETA. GFS LOOKS MOST CONSISTENT...AND HAS BEEN THE 
BEST SO FAT THIS SEASON. HOWEVER WILL NOT THROW OUT THE REST JUST 
YET...SO WILL TAKE A COMPROMISE WITH LOCATION OF FRONT FOR SAT 
MORNING. MAIN CONCERN CONTINUES TO BE THE RESULTING SYSTEM THAT 
MOVES NE ALONG THIS FRONT THROUGH SRN IL SUNDAY AND THE PCPN TYPE. 

SHORT TERM...TONIGHT THROUGH SUNDAY...
CRNT WARM FRONT OVR SRN PARTS OF CWA WILL MOVE NORTHWARD TONIGHT. 
SFC DEWPOINTS OF 45-55F WILL ALSO ADVECT NORTHEASTWARD 
TONIGHT...ALONG WITH LOW LEVEL MOSITURE AIDED BY A 45KT LOW LEVEL 
JET MAX. ALL THIS WILL COMBINE WITH A 70KT MID LEVEL JET FROM THE 
WSW TO PRODUCE LIKELY RWS AND ISOLATED T-STORMS ACRS SRN IL...TO 
INCLUDE SRN PORTIONS OF CWA. RWS ALREADY TO OUR WEST SO WILL UP POPS 
FOR TONIGHT IN SRN HALF OF CWA. MOST OF PCPN WILL BE BEFORE 
MIDNIGHT...SO WILL DROP EVERYTHING AFTER MIDNIGHT EXCEPT FOR SERN 
IL...AND KEEP CHC POPS THERE. NEXT FRONT COMES IN FOR SATURDAY. 
APPEARS DRY AT FIRST...BUT THEN BEGINS TO DEVELOP PCPN AS GULF OPENS 
AND LOW LEVEL MOISTURE RETURNS. PCPN WILL BEGIN AS RAIN FROM NW 
AFTER MIDNIGHT FRIDAY...AND WORK ITS WAY SOUTH TO REST OF CWA. 
CHANGE OVER TO SNOW WILL OCCUR IN NW SAT NIGHT. CHANGE TO SNOW IN 
REMAINDER OF CWA DEPENDS ON SPEED AND COLD AIR. WILL BLEND SPEED OF 
GFS AND ETA...WHICH KEEPS CHANGE OVER LITTLE SLOWER THAN PREVIOUS 
FCST. HOWEVER...PCPN APPEARS LIKELY AS MODELS CONT TO BE CONSISTENT 
WITH PCPN...TYPE IS ONLY QUESTION FOR NOW. SO WILL UP POPS FOR 
SUNDAY AND KEEP CHC FOR SAT NIGHT. WILL NEED TO KEEP AN EYE ON THIS 
SYSTEM.

LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...
SYSTEM PULLS OUT QUICK ENOUGH SUNDAY NIGHT...BUT WILL KEEP CHC POPS 
OF S- FOR SUNDAY NIGHT ACRS AREA. REMAINDER OF EXTENDED WILL BE DRY 
AND COLD AS LARGE HIGH PRESS AREA FROM UP NORTH SLIDES INTO MIDWEST. 
ANOTHER SYSTEM APPROACHES FROM THE NW...LATER THAN PREVIOUS FCST. 
HOWEVER...BELIEVE THIS SYSTEM WILL BE DRY. SO HAVE OPTED TO REMOVE 
CHC OF PCPN FOR TUE AND TUE NIGHT. BELIEVE SYSTEM WILL BE PUSHED 
SOUTH OF AREA...KEEPING US DRY. MOST SURROUNDING OFFICES HAVE DONE 
THE SAME. 

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
IL...NONE.

&&
    
$$

AUTEN

000 
FXUS63 KILX 011624
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1025 AM CST THU JAN 1 2004

.DISCUSSION...
LATEST 15Z SURFACE ANALYSIS PLACES MAIN SURFACE LOW ACROSS NORTHERN 
PLAINS STATES. A SURFACE WARM FRONT WAS ACROSS IOWA SOUTHEAST INTO 
ILLINOIS. LATEST 1545Z IR SATELLITE PLACES PLENTY OF CLOUDS FROM THE 
GREAT LAKES SOUTHWEST INTO THE SOUTHERN PLAINS STATES. LATEST 1606Z 
KILX RADAR INDICATES SOME LIGHT RAIN SHOWERS ACROSS PARTS OF WEST 
CENTRAL ILLINOIS. LATEST 1608Z KLSX RADAR INDICATES MORE SCATTERED 
SHOWERS ACROSS EASTERN MISSOURI. WILL UPDATE ZONES SHORTLY FOR 
WORDING AND SLIGHT TEMPERATURE ADJUSTMENT.  

.PREV DISCUSSION...
LOWER CEILINGS SURGING RAPIDLY INTO FORECAST AREA IN WAA PATTERN. 
WILL UPDATE ZONES/GRIDS TO TWEAK LATEST TRENDS...PRIMARILY TO SPEED 
UP ARRIVAL OF CLOUDS.

.PREV DISCUSSION...
WARM ZONAL FLOW DOMINATES THE WEATHER ACROSS ILLINOIS...FOR 
NOW...WITH THE EXTENDED PATTERN CONTINUING TO SUGGEST A COOL-DOWN
TO WINTER-LIKE TEMPERATURES DURING THE EARLY PART OF NEXT WEEK. 
FORECAST CHALLENGE WILL BE WITH RAIN CHANCES AND WARM TEMPS OVER THE 
NEXT COUPLE DAYS...THEN TRANSITION TO SNOW AND COLDER TEMPS 
OCCURRING OVER THE WEEKEND. EXTENDED TEMP GUIDANCE QUITE A BIT 
COLDER THAN 24 HOURS AGO OFF OF MRF MODEL...SO QUESTION IS HOW COLD 
TO GO NEXT WEEK.

SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...
MADE ONLY A FEW MINOR TWEAKS TO GRIDS DURING THIS PERIOD. HELD OFF 
ON RAIN CHANCES UNTIL THIS AFTERNOON. MODEL CONSENSUS AND ISC GRIDS 
CONFIRM THIS IDEA...WITH THE BEST MOISTURE AND DYNAMICS HOLDING OFF 
UNTIL THEN. ALSO...REMOVED RAIN CHANCES NORTHWEST HALF AFTER 
MIDNIGHT TONIGHT...AS ZONE OF PRECIP CHANCES BY THEN SHIFTS INTO 
SOUTHEAST ILLINOIS. BUFKIT DATA...HOWEVER...SUGGESTS LOW-LEVEL 
MOISTURE TO REMAIN TRAPPED...WITH THE POTENTIAL OF FOG DEVELOPMENT 
IN THE PRECIP-FREE AREA AFTER MIDNIGHT. ADDED THE MENTION OF FOG AS 
A RESULT. FRIDAY LOOK TO BE A DRY AND WARM DAY. MODEL GUIDANCE HAS 
WARMED UP A BIT...AND SEE NO REASON NOT TO FOLLOW THIS TREND. 
NORTHERN STREAM SHORTWAVE ENERGY LIFTING INTO THE WESTERN GREAT 
LAKES REGION BY FRIDAY NIGHT TO DRAG A FRONT THROUGH ILLINOIS. HAVE 
A CHANCE OF RAIN NORTH FRI EVENING...ALL ACROSS THE CWA AFTER 
MIDNIGHT. 

LONG TERM...SATURDAY THROUGH WEDNESDAY...
NEXT WEATHER MAKER SHAPING UP TO LOOK INTERESTING FOR CENTRAL 
ILLINOIS...WITH THE POTENTIAL OF ACCUMULATING SNOW BEFORE A MAJOR 
COOL DOWN. SOUTHERN STREAM WAVE MOVING THROUGH SOUTHERN PLAINS 
SUNDAY TO DEVELOP SURFACE LOW...WITH THE GFS TRACKING THE LOW FM 
SOUTHERN ILLINOIS TO CENTRAL INDIANA BY SUN EVENING. GIVEN THIS 
TRACK...ACCUMULATING SNOWS LOOK LIKE A GOOD POSSIBILITY SUNDAY. WILL 
NEED TO CONTINUE TO MONITOR THIS CLOSELY FOR MODEL CONSISTENCY. FOR 
NOW...CURRENT CHANGEOVER FROM RAIN TO SNOW TRENDS LOOK REASONABLE. 
MADE LITTLE CHANGE HERE. AS STATED EARLIER...EXTENDED MODEL GUIDANCE 
NOW QUITE A BIT COOLER EARLY NEXT WEEK. HAVE TRENDED THIS WAY...BUT 
NOT AS COLD (TEENS HIGHS, SINGLE DIGITS LOWS) AS GUIDANCE NOW SHOWS. 
WITH UPPER LEVEL TROF PARKING OVER THE NORTHERN PLAINS INTO MIDWEST 
DURING THIS PERIOD...SURE DOES LOOK LIKE A RETURN OF THE WINTER 
COLD IS FINALLY ON ITS WAY.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
IL...NONE.

&&
    
$$
PLAHMER/BAK/13