000
FXUS63 KILX 171145
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
645 AM CDT MON JUN 17 2013

.DISCUSSION...
ISSUED 252 AM CDT MON JUN 17 2013

SHORT TERM...TODAY THROUGH WEDNESDAY

VERY WEAK SURFACE BOUNDARY EXTENDING ACROSS SOUTH-CENTRAL ILLINOIS
WILL BE THE PRIMARY FOCUSING MECHANISM FOR SCATTERED THUNDERSTORMS
TODAY. WITH ONE UPPER-WAVE PASSING WELL TO THE NORTH ACROSS THE
GREAT LAKES AND ANOTHER TRACKING TO THE S/SW INTO THE LOWER OHIO
RIVER VALLEY...VERY LITTLE UPPER SUPPORT WILL BE IN PLACE FOR
WIDESPREAD CONVECTION ACROSS CENTRAL ILLINOIS. DESPITE LACK OF
UPPER DYNAMICS...VERY MOIST AIRMASS IN PRESENCE OF WEAK SURFACE
FORCING WILL BE ENOUGH TO TRIGGER A FEW SHOWERS/THUNDERSTORMS
LATER TODAY. HRRR SUGGESTS DEVELOPMENT AROUND MIDDAY...ESPECIALLY
IN CLOSER PROXIMITY TO BOUNDARY. WILL THEREFORE INCLUDE LOW CHANCE
POPS TODAY...WITH BEST RAIN CHANCES SOUTH OF I-72.

SHORT-WAVE TROUGH CURRENTLY EVIDENT ON WATER VAPOR IMAGERY OVER
SOUTHERN SASKATCHEWAN MAY PROVIDE A NEW WRINKLE IN THE FORECAST
FOR TUESDAY. WHILE WE PREVIOUSLY THOUGHT TUESDAY WOULD BE
DRY...LATEST MODEL GUIDANCE IS INDICATING THE POTENTIAL FOR
ISOLATED CONVECTION DURING THE AFTERNOON. THANKS TO A CONTINUED
MOIST AIRMASS AND THE ARRIVAL OF MODEST UPPER FORCING DURING PEAK
HEATING...HAVE INCLUDED A SLIGHT CHANCE FOR THUNDER TUESDAY
AFTERNOON. ONCE THE WAVE PUSHES FURTHER EAST...SURFACE HIGH
PRESSURE WILL BUILD INTO THE REGION FOR TUESDAY NIGHT AND
WEDNESDAY...PROVIDING SEASONABLY WARM AND DRY CONDITIONS.

LONG TERM...THURSDAY THROUGH SUNDAY

00Z 17 JUN MODELS CONTINUE TO SUGGEST A VERY WARM AND LARGELY DRY
EXTENDED FORECAST. ALL MODELS BUILD AN UPPER-LEVEL RIDGE ACROSS
THE PLAINS ON THURSDAY...THEN SHIFT IT INTO THE MIDWEST OVER THE
WEEKEND. PREVIOUS RUNS DISAGREED ON THE EXACT STRENGTH/POSITIONING
OF THE RIDGE...WHICH BROUGHT INTO QUESTION WHETHER ANY MCS
ACTIVITY COULD RIDE UP/OVER THE RIDGE INTO THE AREA DURING THE
PERIOD. LATEST GFS/ECMWF/GEM ARE ALL LOOKING STRONGER WITH THE
RIDGING...KEEPING BEST FORCING FOR NOCTURNAL MCS DEVELOPMENT
FURTHER NORTH ACROSS THE UPPER MIDWEST INTO THE GREAT LAKES. MODELS
INDICATE ONE CONVECTIVE COMPLEX MAY BRUSH THE KILX CWA TO THE
NORTH FRIDAY NIGHT...BEFORE RIDGE BUILDS EVEN FURTHER ON SATURDAY.
HAVE THEREFORE INCLUDED CHANCE POPS ALONG AND NORTH OF A CANTON TO
BLOOMINGTON LINE FRIDAY NIGHT...BUT HAVE GONE WITH A DRY FORECAST
ACROSS THE BOARD FOR THE REMAINDER OF THE EXTENDED. WILL LIKELY
HAVE TO WAIT UNTIL RIDGE BEGINS TO FLATTEN EARLY NEXT WEEK BEFORE
ANY WIDESPREAD RAIN CHANCES RETURN TO THE AREA. GIVEN BUILDING
UPPER HEIGHTS AND LACK OF CONVECTION...HIGH TEMPERATURES WILL
REACH THE UPPER 80S/LOWER 90S WHILE OVERNIGHT LOWS ONLY DROP INTO
THE LOWER 70S FRIDAY THROUGH SUNDAY.

&&

.AVIATION...
ISSUED 645 AM CDT MON JUN 17 2013

AREAS OF FOG WITH IFR TO MVFR CONDITIONS AT PIA AND BMI...LOCALLY
DENSE ALONG I-72 AT SPI...DEC AND CMI WITH LIFR TO VLIFR
CONDITIONS...TO OCCUR UNTIL 13Z/8 AM WITH FOG LIFTING BEFORE
14Z/9 AM. SCATTERED CUMULUS CLOUDS OF 3-5K FT TO DEVELOP LATER
THIS MORNING AND AFTEROON WITH SCATTERED-BROKEN CIRRUS CLOUDS AT
25K FT. ISOLATED SHOWERS AND THUNDERSTORMS TO DEVELOP MAINLY SOUTH
OF I-72 THIS AFTERNOON NEAR A WEAK BOUNDARY AND BE CLOSEST IMPACT
TO SPI AND DEC AIRPORTS WHERE VCSH. SCATTERED CUMULUS CLOUDS
DISSIPATE AT SUNSET WITH SCATTERED CIRRUS CLOUDS. COULD BE PATCHY
FOG AGAIN OVERNIGHT WITH MVFR VSBYS POSSIBLE AFTER 07Z BUT NOT AS
WIDESPREAD AS EARLY THIS MORNING SINCE LARGER TEMPERATURE/DEWPOINT
SPREADS EXPECTED. WINDS TO REMAIN FAIRLY LIGHT UNDER 10 KTS NEXT
24 HOURS...WITH LIGHT AND VARIABLE TO CALM WINDS EARLY THIS
MORNING BECOMING WSW 5-7 KTS BY AFTERNOON AND DIMINISHING LIGHT
AGAIN AFTER SUNSET TONIGHT.

07

&&

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

&&

$$