000
FXUS63 KILX 151746
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1246 PM CDT SAT JUN 15 2013

.DISCUSSION...
ISSUED 1027 AM CDT SAT JUN 15 2013

MCV FROM OVERNIGHT MCS OVER IA NOW SHIFTING THROUGH NE IL.
MESOSCALE BOUNDARY SOUTHWEST OF THIS FEATURE LOOKS TO HAVE SET UP
FROM NEAR BURLINGTON TO SPRINGFIELD AND HAS BEEN THE FOCUS FOR A
CLUSTER OF TSTMS PAST FEW HOURS. THIS IS BEING MAINTAINED BY A
CONVERGENT +20C DEWPOINT FEED AT 925 MB FROM ERN KS AND NRN MO.
HEAVY DOWNPOURS LIKELY GIVEN VERY HIGH P/W OVER 1.6. FEEL THIS
WILL BE MOST CONCENTRATED AREA OF CONVECTION FOR NEXT FEW
HOURS...AS NOT MUCH OF A FOCUS ELSEWHERE AND HAVE REMOVED POPS
EAST OF I-57 AND ONLY HAVE SLIGHT CHANCE NORTH OF CURRENT
ACTIVITY. STILL NOT MUCH OF A FOCUS FOR ADDITIONAL DEVELOPMENT
THIS AFTERNOON...HOWEVER WITH LEFTOVER BOUNDARIES AND INCREASING
INSTABILITY CHANCE POPS FOR THE WESTERN HALF LOOK GOOD. INCREASING
SHEAR WOULD PROVIDE MORE ORGANIZATION LATER IN THE DAY...SO STRONG
OR ISOLATED SEVERE POSSIBLE. BEST CHANCE FOR SVR APPEARS TIED TO
A SHORTWAVE NOW LIFTING NORTHEAST THROUGH CENTRAL KS...AND AHEAD
OF A WEAK COLD FRONT SHIFTING THROUGH NW IA. THIS WOULD FAVOR MORE
INTENSE TSTM DEVELOPMENT OVER NRN MO LATER THIS AFTERNOON...WHICH
WOULD SHIFT INTO WESTERN IL LATE THIS AFTERNOON AND EVENING. HIGH
TEMPS WILL BE A CHALLENGE WITH AREAS OF CLOUD COVER AND PRECIP
ESPECIALLY ACROSS THE SOUTHWEST CWA...BUT SUNNIER LOCATIONS COULD
CERTAINLY SEE HIGHS IN THE MID 80S.



&&

.AVIATION...
ISSUED 1246 PM CDT SAT JUN 15 2013

MAINLY VFR CONDITIONS AGAIN NEXT 24 HOURS OUTSIDE OF
THUNDERSTORMS. CURRENT COMPLEX AFFECTING PARTS OF CENTRAL IL THIS
AFTERNOON WILL PRODUCE BRIEF VSBY REDUCTIONS DOWN TO 4SM AND
POSSIBLY BRIEFLY LOWER IN HEAVIER TSRA. NEXT BATCH OF STORMS
EXPECTED TO FORM OVER IA AND NRN MO LATER THIS AFTERNOON AND SHIFT
OVER THE TAF SITES THIS EVENING AND HAVE TEMPO GROUPS FOR MOST
LIKELY TIME OF OCCURRENCE. AFTER THIS SYSTEM PUSHES THROUGH MUCH
OF THE ACTIVITY SHOULD BE SUPPRESSED TO OUR SOUTH/EAST FOR SUNDAY
MORNING. CHANCE OF SOME VSBY REDUCTIONS AFTER 06Z IN LIGHT WIND
REGIME AND WITH WET GROUND AND HAVE TRENDED THIS DIRECTION FOR
MOST SITES.


25
&&

.PREV DISCUSSION...
ISSUED 243 AM CDT SAT JUN 15 2013

SHORT TERM...TODAY THROUGH MONDAY

07Z IR SATELLITE IMAGERY SHOWS WARMING CLOUD TOPS ASSOCIATED
WITH THE MCS OVER IOWA/NORTHERN MISSOURI. FURTHER DISSIPATION IS
ANTICIPATED AS THE SYSTEM TRACKS E/SE INTO AN INCREASINGLY
UNFAVORABLE AIR MASS EAST OF THE MISSISSIPPI RIVER EARLY THIS
MORNING. BIG QUESTION WILL BE HOW FAR EAST THE PRECIP WILL MAKE
IT BEFORE COMPLETELY DIMINISHING. AS IS TYPICALLY THE CASE WITH
CONVECTION...MOST MODEL GUIDANCE LEAVES A LOT TO BE DESIRED. THE
ONLY MODEL THAT SEEMS TO HAVE A DECENT HANDLE ON THE CURRENT
SITUATION IS THE 05Z HRRR...WHICH BRINGS SHOWERS ACROSS MUCH OF
CENTRAL ILLINOIS THIS MORNING BEFORE FINALLY DISSIPATING THEM
SOUTH OF I-70 TOWARD MIDDAY. GIVEN LATEST SATELLITE/RADAR
TRENDS...THIS SEEMS TO BE A PLAUSIBLE SOLUTION...SO WILL FOLLOW
CLOSELY FOR THE SHORT-TERM. AS A RESULT...WILL CARRY LIKELY POPS
FOR SHOWERS ALONG AND NORTHWEST OF A CHAMPAIGN TO SHELBYVILLE LINE
THROUGH MIDDAY...WITH JUST CHANCE POPS FURTHER E/SE. ONCE THE
DECAYING MCS EXITS INTO INDIANA...THE STABLE AIR MASS LEFT IN ITS
WAKE WILL RESULT IN A LULL IN PRECIP CHANCES FROM LATE MORNING
THROUGH MID-AFTERNOON. HRRR DEPICTS ADDITIONAL CONVECTION FIRING
FURTHER WEST WHERE MUCH GREATER INSTABILITY WILL DEVELOP ACROSS
KANSAS/MISSOURI AFTER 20Z. THINK THIS ACTIVITY WILL GRADUALLY
SPREAD E/NE INTO CENTRAL ILLINOIS LATE THIS AFTERNOON AND EVENING
AHEAD OF AN APPROACHING COLD FRONT. WITH GOOD CONVERGENCE ALONG
THE FRONT...UPPER SUPPORT PROVIDED BY A SIGNIFICANT SHORT-WAVE
TRACKING INTO THE SOUTHERN GREAT LAKES...AND AMPLE MID/LOW-LEVEL
MOISTURE IN PLACE...EXPECT WIDESPREAD SHOWERS/THUNDER ALONG
ADVANCING FRONT. WILL CARRY CATEGORICAL POPS ACROSS ALL BUT THE
FAR SE KILX CWA ACCORDINGLY TONIGHT.

DESPITE QUESTIONABLE CONVECTION FORECASTS IN THE IMMEDIATE
SHORT-TERM...SYNOPTIC MODELS ALL AGREE THAT FRONTAL BOUNDARY WILL
SAG SOUTHWARD THROUGH CENTRAL ILLINOIS ON SUNDAY...SHIFTING THE
GREATEST EMPHASIS FOR ADDITIONAL PRECIP FURTHER SOUTH. WITH WEAK
HIGH PRESSURE BUILDING INTO THE UPPER MIDWEST AND A SLIGHTLY DRIER
AIR MASS TRICKLING SOUTHWARD BEHIND THE BOUNDARY...HAVE REMOVED
MENTIONABLE POPS ACROSS THE NORTHERN CWA ON SUNDAY...THEN ACROSS
THE ENTIRE AREA SUNDAY NIGHT.

ANOTHER SHORT-WAVE TROUGH IS PROGGED TO DIG E/SE ACROSS THE UPPER
MIDWEST INTO THE GREAT LAKES EARLY NEXT WEEK. SYNOPTIC LIFT PROVIDED
BY THIS FEATURE IN CONJUNCTION WITH ANOTHER FRONTAL BOUNDARY IN
THE AREA WILL BE ENOUGH TO TRIGGER SCATTERED SHOWERS/THUNDER ON
MONDAY. FRONT WILL THEN SETTLE FURTHER SOUTHWARD MONDAY
NIGHT...TAKING RAIN CHANCES OUT OF THE AREA OVERNIGHT.

LONG TERM...TUESDAY THROUGH FRIDAY

A RELATIVELY QUIET PERIOD OF WEATHER IS EXPECTED IN THE
EXTENDED...AS A SOMEWHAT COOLER W/NW UPPER FLOW EARLY IN THE
PERIOD IS GRADUALLY REPLACED BY RIDGING BY THE END OF THE WEEK. AS
A RESULT...HIGH TEMPS IN THE UPPER 70S ON TUESDAY WILL WARM INTO
THE MIDDLE TO UPPER 80S BY FRIDAY. MODELS CONTINUE TO SPLASH LIGHT
QPF ACROSS THE AREA FROM TIME TO TIME THROUGHOUT THE
PERIOD...HOWEVER THINK THIS IS WAY OVERDONE. WILL KEEP MENTIONABLE
POPS OUT OF THE FORECAST...UNTIL STRONGER/MORE CONSISTENT SIGNALS
FOR PRECIP DEVELOP.

BARNES


&&

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

$$