000
FXUS63 KILX 151136
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
636 AM CDT SAT JUN 15 2013

.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

&&

.AVIATION...
ISSUED 635 AM CDT SAT JUN 15 2013

TRICKY TAF FORECAST DUE TO TIMING OF CONVECTIVE REDEVELOPMENT.
EARLIER MCS HAS FADED QUICKLY THE LAST COUPLE HOURS...AND WILL
ONLY SEE A FEW SHOWERS OVER THE TAF SITES THROUGH ABOUT MID
MORNING. CLUSTER OF SHOWERS CURRENTLY IN THE SOUTHEAST TIP OF
IOWA ON TRACK TO REACH KPIA BY 1430Z IF IT HOLDS TOGETHER. THINK
THERE WILL BE A LULL IN THE PRECIP FOR A GOOD PORTION OF THE LATE
MORNING AND EARLY AFTERNOON BEFORE MORE STORMS BEGIN TO REDEVELOP.
MODELS ARE HAVING A HARD TIME AGREEING ON THE LOCATION OF THIS
REDEVELOPMENT...NOT UNUSUAL GIVEN THAT LEFTOVER SUBTLE BOUNDARIES
FROM THE MORNING CONVECTION WILL PLAY A ROLE. THUS...WILL
GENERALLY STICK WITH VCTS MENTION UNTIL MORE CONSISTENT SIGNALS
APPEAR...ALTHOUGH HAVE INCLUDED A FEW HOURS OF TEMPO TSRA PERIODS
LATE AS A FRONTAL BOUNDARY PUSHES THROUGH THE AREA.

GEELHART

&&

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

$$