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000
FXUS63 KILX 250742
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
242 AM CDT SAT MAY 25 2013

.DISCUSSION...
ISSUED 242 AM CDT SAT MAY 25 2013

UNSETTLED WEATHER THROUGH THE MEMORIAL DAY WEEKEND...FOLLOWED BY
MUCH WARMER/DRIER CONDITIONS FOR THE MIDDLE AND END OF NEXT WEEK.

SHORT TERM...TODAY THROUGH MONDAY

CONVECTION CURRENTLY DEVELOPING ALONG THE NOSE OF A 45-50KT LLJ
OVER NEBRASKA IS EXPECTED TO TRACK E/SE INTO THE AREA TODAY. MAIN
QUESTION WILL BE HOW FAR EAST THE PRECIP CAN PENETRATE INTO
SPRAWLING SURFACE RIDGE AXIS EXTENDING FROM THE GREAT LAKES TO THE
GULF COAST. 00Z KILX UPPER AIR SOUNDING SHOWED A VERY DRY PROFILE
FROM THE SURFACE UP TO ABOUT 500MB. ANY PRECIP MOVING INTO THIS
HOSTILE ENVIRONMENT WILL INITIALLY EVAPORATE UNTIL THE AIRMASS IS
SUFFICIENTLY MOISTENED. DUE TO THE CONTINUED DRY E/NE LOW-LEVEL
FLOW...HAVE REMOVED POPS ACROSS EAST-CENTRAL AND SOUTHEAST
ILLINOIS FOR THE MORNING HOURS. FURTHER WEST...HIGH-RES HRRR
SUGGESTS NEBRASKA CONVECTION WILL EVENTUALLY SPREAD INTO
WEST-CENTRAL ILLINOIS TOWARD MIDDAY. WILL THEREFORE CARRY CHANCE
POPS DURING THE MORNING...THEN LIKELY THIS AFTERNOON FOR LOCATIONS
ALONG/WEST OF I-55.

INITIAL AREA OF CONVECTION WILL DISSIPATE AS IT MOVES INTO
EAST-CENTRAL ILLINOIS LATER THIS AFTERNOON AND EVENING.
MEANWHILE...LOW-LEVEL JET WILL ONCE AGAIN STRENGTHEN AND FOCUS A
RENEWED ROUND OF SHOWERS/THUNDER UPSTREAM ACROSS IOWA TONIGHT.
THIS ACTIVITY IS THEN EXPECTED TO TRACK E/SE INTO CENTRAL ILLINOIS
LATE TONIGHT INTO SUNDAY. WITH AIRMASS MOISTENED FROM INITIAL
PRECIP TODAY...THINK RAIN CHANCES WILL BE HIGHER ACROSS THE BOARD
TONIGHT/SUNDAY. WILL THEREFORE CARRY LIKELY POPS EVERYWHERE EXCEPT
THE FAR SE CWA.

ADDITIONAL SHOWERS/STORMS WILL FIRE ON MONDAY...AS PERSISTENT
FRONTAL BOUNDARY FINALLY BEGINS TO SHIFT SLOWLY NORTHWARD ACROSS
THE AREA. WILL CONTINUE TO HIT POPS HARD...ESPECIALLY ACROSS THE
CENTRAL AND NORTHERN ZONES. TOTAL RAINFALL FROM THIS MULTI-DAY
EVENT WILL BE LIGHTEST ALONG THE ILLINOIS/INDIANA BORDER WHERE
AMOUNTS OF ONE HALF TO ONE INCH WILL BE COMMON. HIGHER RAIN TOTALS
WILL BE FOCUSED FURTHER WEST...ESPECIALLY WEST OF I-55 WHERE ONE
AND A HALF TO TWO INCHES WILL BE LIKELY.

LONG TERM...TUESDAY THROUGH FRIDAY

AS UPPER TROUGH DIGS OVER THE WESTERN CONUS...DOWNSTREAM RIDGE
WILL BUILD ACROSS THE MIDWEST/OHIO RIVER VALLEY. THIS WILL FINALLY
GIVE THE SURFACE FRONT A GOOD PUSH NORTHWARD BY TUESDAY...RESULTING
IN LOWER POPS AND HIGHER TEMPS. WILL ONLY CARRY LOW CHANCE POPS
ACROSS THE FAR NORTHERN CWA...WHILE HIGH TEMPS CLIMB INTO THE
LOWER TO MIDDLE 80S. AFTER THAT...MODEL SOLUTIONS VARY SOMEWHAT
CONCERNING HOW QUICKLY THE UPPER RIDGE EVENTUALLY BREAKS DOWN.
GIVEN AMPLIFIED PATTERN...THINK THIS WILL BE LATER RATHER THAN
SOONER...SO HAVE GONE WITH A VERY WARM AND DRY FORECAST THROUGH
THURSDAY. WEAKENING FRONTAL BOUNDARY MAY PUSH INTO THE REGION BY
THE END OF THE WEEK...SO HAVE INCLUDED CHANCE FOR SHOWERS/THUNDER
ON FRIDAY WITH CONTINUED WARM TEMPS WELL INTO THE 80S.

BARNES
&&

.AVIATION...
ISSUED 1105 PM CDT FRI MAY 24 2013

VFR CONDITIONS ARE EXPECTED THRU THIS FORECAST PERIOD (06Z/26TH).

BAND OF MID LEVEL CLOUDS OUT AHEAD OF A WEAKENING AREA OF SHOWERS
ACRS EAST CENTRAL IOWA WILL CONTINUE TO TRACK ESE INTO THE REGION
DURING THE EARLY MORNING HOURS. JUST HOW FAR EAST THE SHOWERS WILL
GET IS STILL A CHALLENGE AS FORECAST SOUNDINGS CONTINUE TO EXHIBIT
SOME VERY DRY AIR HOLDING AT THE LOW LEVELS OF THE ATMOSPHERE.
SURFACE OBS UNDERNEATH SOME OF THE HIGHER REFLECTIVITIES OVER EAST
CENTRAL IOWA WERE NOT REPORTING MUCH IN THE WAY OF RAINFALL. MAY
PUT IN A VCSH AT PIA AND SPI IF THIS INITIAL BAND CONTINUES EAST
OVER THE NEXT HOUR. FURTHER OUT IN TIME FOR SATURDAY...NOT MUCH IN
THE WAY OF CHANGE FROM PREVIOUS THINKING...WE MAY SEE SOME LOWER
VFR CIGS MOVE IN ACRS THE WEST DURING THE DAY BUT TRYING TO TIME
IN SHOWERS OR TSRA AT ANY ONE PARTICULAR LOCATION IS STILL A
CHALLENGE SO WILL CONTINUE WITH VCSH/OR VCTS. MODELS HAVE STARTED
TO TREND WITH THE IDEA OF SOME RAIN COMING INTO THE AREA LATER
IN THE MORNING...WITH A BREAK BY MID OR LATE AFTN...WITH MORE
SHOWERS AND TSRA MOVING BACK IN LATER TOMORROW NIGHT.

WINDS WILL REMAIN LIGHT EASTERLY TONIGHT...AND EAST TO SOUTHEAST
AT 8 TO 13 KTS ON SATURDAY INTO SATURDAY NIGHT.

SMITH
&&

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

$$