225 FXUS63 KILX 291744 AFDILX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1244 PM CDT FRI JUN 29 2012 .DISCUSSION... ISSUED 1034 AM CDT FRI JUN 29 2012 ANOTHER EXTREMELY HOT DAY IS UNFOLDING ACROSS CENTRAL AND SOUTHEAST ILLINOIS...WITH 15Z TEMPS ALREADY WELL INTO THE 90S ACROSS THE SE KILX CWA. READINGS ARE SLIGHTLY COOLER ACROSS THE FAR NORTH...WHERE A FEW CLOUDS AND HIGHER DEWPOINTS ARE KEEPING TEMPS DOWN JUST A BIT. FRONTAL BOUNDARY THAT SAGGED SOUTHWARD TO NEAR THE I-74 CORRIDOR LAST NIGHT IS LIFTING BACK NORTHWARD...KEEPING THE BEST CHANCES FOR CONVECTION CONFINED TO NORTHERN ILLINOIS. LATEST SATELLITE/RADAR IMAGERY CONTINUES TO SHOW DEVELOPING STORM COMPLEX TRACKING EASTWARD ALONG THE I-80 CORRIDOR. SOME OF THE HIGHER-RES MODELS SUCH AS THE 11Z HRRR SUGGEST THIS COMPLEX WILL EVENTUALLY BECOME SURFACE-BASED AND TAKE A TURN E/SE ALONG THE BOUNDARY. BASED ON LATEST TRENDS...IT APPEARS THAT BY THE TIME THIS HAPPENS THE STORMS WILL LIKELY MISS THE KILX CWA TO THE N/NE...EVENTUALLY SPILLING SOUTHEASTWARD INTO NORTH-CENTRAL INDIANA THIS AFTERNOON. ONLY CHANCE FOR CONVECTION ACROSS CENTRAL ILLINOIS WOULD BE POSSIBLE ISOLATED STORMS ALONG RESIDUAL OUTFLOW BOUNDARY LATER TODAY. HAVE THEREFORE TRIMMED POPS CONSIDERABLY...FEATURING ONLY A SLIGHT CHANCE ALONG/NORTH OF I-74. TEMP FORECAST LOOKS PRETTY MUCH ON TRACK...WITH HIGHS RANGING FROM THE MID 90S FAR NORTH AROUND LACON TO OVER 105 DEGREES ALONG/SOUTH OF I-70. && .AVIATION... ISSUED 1244 PM CDT FRI JUN 29 2012 CONVECTIVE OUTFLOW BOUNDARY WILL CONTINUE TO SETTLE SOUTHWARD ACROSS NORTH-CENTRAL ILLINOIS EARLY THIS AFTERNOON...BEFORE EVENTUALLY STALLING AND MIXING BACK NORTHWARD LATER IN THE DAY. LATEST SATELLITE/RADAR IMAGERY SHOWS THE BOUNDARY STRETCHING FROM NEAR KBMI TO JUST NORTH OF KMQB. BASED ON THE CURRENT POSITION AND THE 14Z HRRR FORECAST...HAVE GONE WITH GUSTY N/NE WINDS AT BOTH KPIA AND KBMI THROUGH 20Z...THEN HAVE VEERED THE WINDS BACK TO S/SW AT THOSE SITES AFTER 22Z. FURTHER SOUTH...WILL MAINTAIN WESTERLY WINDS OF AROUND 10KT THROUGH THE AFTERNOON. W/SW WINDS WILL RESUME ACROSS THE BOARD TONIGHT INTO SATURDAY MORNING. ADDITIONAL CONVECTION MAY RE-DEVELOP IN THE VICINITY OF A STATIONARY FRONTAL BOUNDARY DRAPED ALONG THE I-80 CORRIDOR OVERNIGHT...HOWEVER THINK THIS WILL MAINLY STAY NORTH OF THE KILX TERMINALS. LATER FORECASTS MAY NEED TO ADJUST FOR CLOUD COVER/WIND DIRECTION AS OUTFLOW FROM ANY STORMS TO THE NORTH MAY IMPACT THE I-74 TAF SITES. AT THIS POINT...UNCERTAINTY IS TOO GREAT TO INCLUDE THESE POTENTIAL MESOSCALE DETAILS IN THE FORECAST. BARNES && .PREV DISCUSSION... ISSUED 317 AM CDT FRI JUN 29 2012 AT 06Z SFC FRONT HAD STALLED ALONG THE IA/MO BORDER EAST TO NEAR KPIA AND INTO NORTHERN IND. MID/UPPER 70S DEWPOINTS POOLED ALONG THE BOUNDARY. ALOFT...A LARGE MID LEVEL RIDGE OCCUPIED MUCH OF THE SOUTHERN HALF OF THE COUNTRY WHILE A FAST ZONAL FLOW WAS FARTHER NORTH. WATER VAPOR IMAGERY INDICATED SUBTROPICAL MOISTURE PLUME FROM THE DESERT SW UP INTO THE CENTRAL PLAINS AND ACROSS THE LOCAL AREA...ON THE PERIPHERY OF THE RIDGE. FORECAST CONCERNS REMAIN HIGH HEAT THROUGH THE PERIOD AND CONVECTION CHANCES IN RING OF FIRE PATTERN ON NORTHERN FRINGE OF THE RIDGE. SHORT TERM...TODAY THROUGH SUNDAY LOW CONFIDENCE FORECAST IN CONVECTIVE TRENDS NEXT FEW DAYS AS MESOSCALE FEATURES DRIVE THUNDERSTORM ACTIVITY. NORTHERN CWA WILL BE IN CLOSER PROXIMITY TO FAVORABLE SYNOPTIC FEATURES...SFC BOUNDARY AND STRONGER MID LEVEL FLOW/SHORTWAVE ENERGY TRACK. HIGH INSTABILITY...MODERATE SHEAR...AND HIGH PRECIPITABLE WATER WILL LEAD TO POTENTIAL FOR SEVERE MCS/S AND LOCALLY HEAVY RAIN WHICH MAY IMPACT OR STAY JUST NORTH OF THE CWA. FOR THESE REASONS WILL KEEP LOW CHC POPS GOING PRIMARILY NORTH OF A CANTON TO BLOOMINGTON THROUGH SATURDAY NIGHT...TAPERING TO SLIGHT CHC CENTRAL. A STRONGLY CAPPED AIRMASS SHOULD SUPPRESS ANY DEVELOPMENT ACROSS THE SOUTH HALF. HIGHER CONFIDENCE IN TEMPERATURES WHICH WILL STAY VERY HOT THROUGH THIS WEEKEND. IN FACT TODAYS READINGS MAY NOT BE FAR OFF YESTERDAYS NUMBERS WHICH WERE 100+ FOR MUCH OF THE AREA. TEMPS COOL ONLY A FEW DEGREES THIS WEEKEND WITH HIGHS STILL IN THE MID OR UPPER 90S NORTH AND LOW 100S SOUTH. APPARENT TEMPS ONLY DROPPING INTO THE UPPER 70S TONIGHT WILL REQUIRE EXTENDING HEAT ADVISORY TO 12Z SATURDAY. AREAS SOUTH OF I-70 LOOK TO BE BORDERLINE FOR ADVISORY CRITERIA AGAIN ON SATURDAY AFTERNOON AND ADVISORY MAY NEED TO BE EXTENDED HERE IN LATER FORECASTS. LONG TERM...MONDAY THROUGH THURSDAY UNFORTUNATELY NO PROSPECTS FOR A MAJOR PATTERN CHANGE IN THE EXTENDED TO BRING COOLER AIR INTO THE MIDWEST. LATEST GUIDANCE SUGGESTS MID LEVEL RIDGING SHIFTING EVEN FARTHER NORTH THROUGH THE WEEK. THIS WOULD DRIVE MCS TRACK FARTHER NORTH LEAVING A DRY AND HOT FORECAST FOR THE ENTIRE CWA THROUGH THURSDAY. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 7 AM CDT SATURDAY FOR ILZ027>031-036>038- 040>057-061>063-066>068-071>073. && $$