520 
FXUS63 KILX 312347
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
647 PM CDT TUE JUL 31 2012

.DISCUSSION...
ISSUED 254 PM CDT TUE JUL 31 2012

LATEST SURFACE ANALYSIS HAD A WEAK COLD FRONT CUTTING ACROSS THE
FORECAST AREA...CURRENTLY EXTENDING FROM MCLEAN COUNTY TO SCHUYLER
COUNTY. SATELLITE LOOPS SHOW A LINE OF AGITATED CU JUST AHEAD OF
THE FRONT...WITH AN OCCASIONAL THUNDERSTORM ALSO MAKING AN
APPEARANCE. THIS FRONT WILL QUICKLY LEAVE THE FORECAST AREA THIS
EVENING...WITH THE NEXT BEST CHANCE FOR PRECIPITATION NOT EXPECTED
TO ARRIVE UNTIL A STRONGER FRONT PUSHES THROUGH SATURDAY/SATURDAY
NIGHT. MAIN FORECAST PROBLEMS TODAY REVOLVE AROUND TEMPERATURES
THOROUGH THE PERIOD...AS WELL AS PRECIPITATION CHANCES IN THE
VICINITY OF THE NEXT FRONT.

12Z MODELS IN GOOD AGREEMENT OVER THE NEXT SEVERAL DAYS WITH THE
MAIN FEATURES. HOWEVER...DIFFERENCES STILL EXIST WITH THE MORE
SUBTLE WAVES IN ADVANCE OF SATURDAY/S STRONGER SYSTEM...AND IT IS
DIFFICULT TO FAVOR ANY ONE MODEL SOLUTION WITH RESPECT TO THESE
FEATURES. WILL CONTINUE TO FOLLOW A MODEL BLEND IN THIS REGARD AND
DOWNPLAY THE PRECIPITATION RISK UNTIL THE END OF THE WEEK SYSTEM.

SHORT TERM...TONIGHT THROUGH FRIDAY...EXPECT CURRENT
FRONT/PRECIPITATION RISK TO BE OUT OF THE AREA BY 00Z TONIGHT...SO
DO NOT PLAN TO CARRY POPS TONIGHT. BEHIND THE FRONT...THE
NORTHWEST UPPER LEVEL FLOW TURNS MORE NEUTRAL AND A SURFACE HIGH
WILL BUILD ACROSS THE AREA INTO THURSDAY.

A WEAK UPPER LEVEL WAVE WILL PUSH A WEAK FRONT THROUGH THE AREA
LATER THURSDAY INTO THURSDAY NIGHT. THE FORCING WITH THIS FEATURE
IS MEAGER...SO WILL LIMIT POPS TO SLIGHT CHANCE AT THIS TIME.
ANOTHER WEAK WAVE WILL RIDE ALONG THE FRONT ON FRIDAY AFTER IT HAS
CLEARED THE AREA. A FEW MODEL SOLUTIONS THROW SOME PRECIPITATION
BACK NORTH INTO THE FORECAST AREA AS IT PASSES BY...BUT HAVE AGAIN
LIMITED POPS TO THE SLIGHT CHANCE CATEGORY GIVEN THE WEAK FORCING
AND MODEL TENDENCIES TO OVERDO PRECIPITATION DURING THE CURRENT
DROUGHT.

TEMPERATURES SHOULD REMAIN PRETTY STEADY STATE THROUGH THE PERIOD...
WITH DAYTIME HIGHS IN THE 90S AND OVERNIGHT LOWS MAINLY IN THE
70S. HOWEVER...LOWS IN THE 60S ARE LIKELY TONIGHT AND POSSIBLE
WEDNESDAY NIGHT DUE TO THE LOWER DEW POINT AIR THAT WILL FILTER IN
BEHIND TODAY/S COLD FRONT.

LONG TERM...SATURDAY THROUGH TUESDAY...A STRONGER WAVE WILL PUSH A
FRONT THROUGH THE AREA SATURDAY/SATURDAY NIGHT. THIS FAIRLY VIGOROUS
SYSTEM SHOULD PROVIDE THE BEST CHANCE FOR MORE WIDESPREAD
PRECIPITATION THAN WE HAVE SEEN IN A WHILE AS IT MOVES THROUGH.
HOWEVER...THAT IS NOT SAYING MUCH THIS SUMMER AND IT SHOULD HAVE
LITTLE TO NO IMPACT ON THE CURRENT DROUGHT. SOUTHERLY FLOW AHEAD
OF THIS STRONGER SYSTEM IS APT TO MAKE SATURDAY THE WARMEST DAY OF
THE NEXT SEVEN...WITH SOMEWHAT COOLER CONDITIONS EXPECTED IN ITS
WAKE.

BAK

&&

.AVIATION...
ISSUED 647 PM CDT TUE JUL 31 2012...FOR THE 00Z TAFS

THE CU FIELD IS QUICKLY CLEARING BEHIND THE WEAK COLD FRONT THAT
IS MOVING SOUTH. NO STORMS OR EVEN SHOWERS WILL AFFECT THE
TERMINALS THIS EVENING OR THROUGH TOMORROW FOR THAT MATTER. THE
CLOUDS OF MENTION MAY BE SOME AC AT 10K FT IN THE HEAT OF THE DAY
TOMORROW.

WINDS AT ALL TERMINAL SITES HAVE SHIFTED AROUND TO THE NORTH-
NORTHWEST BEHIND THE FRONT. WINDS WILL GRADUALLY SHIFT TO THE NE
BY SUNRISE THEN EAST DURING THE DAY. SUSTAINED SPEEDS SHOULD
REMAIN AOB 10KT IN THE WEAK SURFACE PRESSURE GRADIENT. 

GFS MOS IS HIGHLIGHTING SOME MVFR FOG LATE TONIGHT...BUT THE GFS
HAS BEEN WAY TOO MOIST IN THE BOUNDARY LAYER DEPICTION OF
LATE...SO WE WILL NOT INCLUDE ANY FOG IN THE TAFS.

SHIMON
&&

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

$$