000
FXUS63 KILX 191724
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1224 PM CDT SUN MAY 19 2013

.DISCUSSION...
ISSUED 1008 AM CDT SUN MAY 19 2013

EARLIER CONVECTION JUST MISSED THE NORTHWEST CORNER OF THE
CWA...AND HAS BEEN STEADILY WEAKENING AS IT MOVES THROUGH FAR
NORTHWEST ILLINOIS. HAD BEEN SEEING WEAKENING CONVECTION OVER
MISSOURI AS THE EARLIER MCS IN KANSAS FADED OUT...BUT LATEST RADAR
IMAGERY FROM ST LOUIS SHOWING SOME RENEWED INTENSIFICATION IN
NORTHEAST AND CENTRAL MISSOURI WHERE THE CAP HAS BEEN WEAKENING.
HAVE INCREASED RAIN CHANCES TO AROUND 50 PERCENT ACROSS THE
WESTERN CWA TO ACCOUNT FOR THE NORTH-NORTHEAST MOVEMENT OF THESE
STORMS. LATEST RAP/HRRR ALSO SHOW SOME ADDITIONAL DEVELOPMENT IN
NORTHERN MISSOURI THIS AFTERNOON WITH POTENTIAL TO AFFECT AREAS
NORTHWEST OF THE ILLINOIS RIVER...SO HAVE NOT CHANGED POPS IN THE
LATER AFTERNOON.

GEELHART


&&

.AVIATION...
ISSUED 1223 PM CDT SUN MAY 19 2013

MAIN CHALLENGE WILL BE WITH TIMING OF THUNDER CHANCES. EARLIER
STORMS HAD THAT HAD MOVED THROUGH WEST CENTRAL ILLINOIS HAVE
LARGELY DIED OUT...BUT SOME RENEWED DEVELOPMENT IS SHOWN BY SOME
OF THE MODELS ACROSS MISSOURI THIS AFTERNOON WHERE INSTABILITY IS
GREATEST. AT THE MOMENT...HAVE ONLY INCLUDED VCTS AT KPIA FOR
THESE STORMS...DUE TO THE NORTHEAST MOVEMENT. A LARGER LINE OF
SHOWERS/STORMS IS LIKELY TO FORM OVER MISSOURI/KANSAS THIS EVENING
AND MOVE EAST. HOW INTACT IT IS WHEN IT MAKES IT THIS FAR EAST IS
STILL UP FOR DEBATE...SO WILL LEAVE VCTS MENTION LATE IN THE
NIGHT FOR NOW AND CONTINUE TO EVALUATE FOR THE 00Z ISSUANCE. MAY
SEE A FEW STORMS DEVELOP AGAIN LATE MONDAY MORNING...BUT AFTERNOON
SEEMS MOST LIKELY FOR NEW CONVECTION.

GEELHART

&&

.PREV DISCUSSION...
ISSUED 330 AM CDT SUN MAY 19 2013

SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

WILL CONTINUE MENTION OF PATCHY FOG OVER EASTERN IL EAST OF I-57
INTO MID MORNING AND HAS BEEN DENSE AT TIMES NEAR THE WABASH RIVER
AT LAWRENCEVILLE. UPPER LEVEL RIDGE BUILDING INTO IL TODAY WILL
BRING A VERY WARM AND MORE HUMID DAY TO CENTRAL/SE IL WITH HIGHS
IN THE MID TO UPPER 80S. DEWPOINTS IN THE LOWER 60S TO RISE INTO
THE UPPER 60S TO NEAR 70F THIS AFTERNOON WITH AIR MASS GETTING
INCREASINGLY MORE UNSTABLE. ONE FRONTAL BOUNDARY WAS NE OF CENTRAL
IL FROM CENTRAL INDIANA INTO NE IL AND SOUTHERN MN. ANOTHER WARM
FRONT OVER SOUTHERN MO TO NEAR THE KY/TN BORDER WILL LIFT
NORTHWARD ACROSS CENTRAL/SE IL DURING THIS AFTERNOON AND WILL
DEVELOP ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TODAY OVER
CENTRAL AND SW AREAS ESPECIALLY THIS AFTERNOON. ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS ARRIVES TONIGHT AS SHORT WAVE ENERGY
EJECTS ENE FROM THE CENTRAL PLAINS TOWARD WESTERN IL ESPECIALLY
FROM I-55 WEST WHERE SPC HAS A SLIGHT RISK OF SEVERE STORMS FOR
15% RISK OF LARGE HAIL AND DAMAGING WIND GUSTS AND 2% RISK OF A
TORNADO.

ANOTHER SLIGHT RISK OF SEVERE STORMS MONDAY AFTERNOON AND MON EVENING
FROM CHAMPAIGN TO TAYLORVILLE WEST. MODELS TAKE CUTOFF UPPER LEVEL
LOW FROM WY SLOWLY EAST ACROSS THE NORTHERN PLAINS EARLY THIS WEEK
REACHING EASTERN SD BY SUNSET MON AND MOVING VERY LITTLE ON TUE.
MUCH OF IL IS IN A SLIGHT RISK OF SEVERE STORMS TUE
AFTERNOON/EVENING DUE TO SLOW MOVEMENT OF STORM SYSTEM TO OUR NW.
CENTRAL/SE IL STAYS IN UNSTABLE WARM SECTOR WITH VERY WARM AND
HUMID AIR. HIGHS MONDAY IN THE MID TO UPPER 80S AGAIN AND LOW TO
MID 80S ON TUE AND COULD BE WARMER ESPECIALLY OVER EASTERN IL IF
WE GET ENOUGH SUNSHINE. QUESTION TO CHANCES OF SEVERE STORMS NEXT
FEW DAYS IS AMOUNT OF HEATING/SUNSHINE WE CAN GET TO GIVE A MORE
UNSTABLE AIR MASS. HAVE SOME WIND SHEAR NEXT FEW DAYS THOUGH MORE
UNIDIRECTIONAL BY TUE. HAVE CHANCES OF SHOWERS/THUNDERSTORMS
THROUGH MID WEEK WITH BEST CHANCES TUE-WED AS UPPER LEVEL LOW
MOVES EAST INTO NORTHERN IL/SOUTHERN WI WED. RISK OF SEVERE STORMS
APPEARS TO SHIFT EAST OF IL WED BUT IF SYSTEM MOVES SLOWER...EASTERN
AND SE IL MAY STILL BE A RISK OF A FEW STRONG TO SEVERE STORMS
WED.

LONG TERM...THURSDAY THROUGH SUNDAY

UPPER LEVEL TROF OVER THE GREAT LAKES AND OHIO VALLEY THU LINGERS
A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS OVER
CENTRAL/EASTERN IL WITH COOLER TEMPERATURES WITH HIGHS IN THE LOW
TO MID 70S CENTRAL IL AND MID TO UPPER 70S IN SE IL. DRY
CONDITIONS SHOULD FINALLY RETURN TO IL BY FRIDAY AND FRIDAY NIGHT
AS 1030 MB HIGH PRESSURE SETTLES INTO THE GREAT LAKES REGION.
MODELS THAT APPEARED TO BE DRY FOR THE END OF THE WEEK...NOW HAVE
DIFFERENT SOLUTIONS ESPECIALLY ECMWF WHICH IS BRINGING QPF INTO IL
AS EARLY AS SAT AFTERNOON INTO SUNDAY. GFS MODEL IS STILL
GENERALLY DRY WITH UPPER LEVEL RIDGING MOVING BACK TOWARD IL. WILL
TRIM POPS TO SLIGHT CHANCES FROM SAT AFTERNOON INTO SUNDAY.

07


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$