000
FXUS63 KILX 220829
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
329 AM CDT WED MAY 22 2013

.DISCUSSION...
ISSUED 330 AM CDT WED MAY 22 2013

SHORT TERM...TODAY THROUGH FRIDAY NIGHT

SHOWERS WILL BE LIKELY TODAY ALONG WITH A CHANCE OF THUNDERSTORMS
ESPECIALLY OVER EASTERN IL. THIS DUE TO A COLD FRONT MOVING EAST
ACROSS IL TODAY AS 1004 MB LOW PRESSURE OVER NORTHCENTRAL IA
TRACKS EAST ALONG THE WI/IL BORDER. 559 DM 500 MB LOW NEAR THE
MN/SD BORDER TO MOVE INTO NE IA BY SUNSET. SPC KEEPS SLIGHT RISK
OF SEVERE STORMS EAST OF IL OVER THE EASTERN 2/3RD OF INDIANA AND
EAST INTO OHIO AND CENTRAL/EASTERN KY. COOLER TODAY WITH MORE
CLOUDS AND RAIN SHOWERS AROUND. CLOSE TO NORMAL HIGHS TODAY MOSTLY
IN THE MID 70S...BUT RANGE FROM THE LOWER 70S OVER THE IL RIVER
VALLEY TO THE UPPER 70S IN SE IL ESPECIALLY NEAR THE WABASH RIVER.

CONTINUED A 20-40% CHANCE OF SHOWERS TONIGHT AND THU AS UPPER
LEVEL LOW MOVES TO NEAR CHICAGO BY 06Z/1 AM TONIGHT AND ASSOCIATED
UPPER LEVEL TROF SHIFTS EAST OVER IL INTO INDIANA THU MORNING.
LOWS TONIGHT IN THE MID TO UPPER 50S. EVEN COOLER THU WITH HIGHS
IN THE MID TO UPPER 60S WITH COOLEST READINGS FROM I-74 NE WHERE
EVEN SOME LOWER 60S POSSIBLE WHERE SKIES WILL STAY CLOUDIER.

LOW CLOUDS CLEAR LATER THU AFTERNOON INTO THU EVENING AS 1030 MB
CANADIAN HIGH PRESSURE SETTLES INTO WI/IL BY FRI MORNING AND INTO
MI BY SUNSET FRI. MODELS CONTINUE TO TREND COOLER FOR LOWS THU NIGHT
NOW IN THE LOWER 40S WITH CLEARING SKIES AND LIGHT WINDS. HIGHS
FRI IN THE MID TO UPPER 60S DESPITE RETURN OF SUNSHINE. IL STARTS
TO GET INTO A WARM AIR ADVECTION FLOW DURING FRI NIGHT ESPECIALLY
AFTER MIDNIGHT WHEN 20-30% CHANCE OF SHOWERS AND ISOLATED
THUNDERSTORMS ARRIVES WEST OF I-57 WITH BEST CHANCES NW OF THE IL
RIVER. NOT AS COOL FRI NIGHT AS CLOUDS INCREASE AND SE FLOW WITH
LOWS IN THE UPPER 40S AND LOWER 50S.

LONG TERM...SATURDAY THROUGH WEDNESDAY

MODELS AGREE WITH UPPER LEVEL RIDGE OVER THE GREAT PLAINS BY THIS
MEMORIAL DAY WEEKEND WITH IL IN A NW UPPER LEVEL FLOW. SURFACE
HIGH PRESSURE NEAR THE GREAT LAKES REGION GIVING A RETURN
SOUTHERLY FLOW TO IL AS BELOW NORMAL TEMPS LATE THIS WEEK
GRADUALLY WARM UP DURING EARLY NEXT WEEK. BUT MODELS DIFFER ON
DISTURBANCE RIDGING OVER THE TOP OF THE UPPER LEVEL RIDGE AND
ASSOCIATED QPF FIELDS. TRIED TO STAY CONSISTENT WITH PREVIOUS
FORECAST AND WITH EXTENDED MODEL TRENDS WHICH SHOWS HIGHER POPS
THIS WEEKEND OVER THE IL RIVER VALLEY AND LESS CHANCES IN SE IL.
HIGHEST CHANCES APPEAR TO BE AFTER MIDNIGHT SAT NIGHT AND SUNDAY
AND HAVE 50% CHANCE OF CONVECTION NW HALF THEN. TEMPS AND HUMIDITY
LEVELS RISE FROM SUNDAY THROUGH WEDNESDAY AND HAVE CHANCE OF
CONVECTION LINGERING THROUGH WED THOUGH MODELS TRENDING WITH
CONVECTION CHANCES SHIFTING NORTH OF CENTRAL IL DURING NEXT WORK
WEEK.

07

&&

.AVIATION...
ISSUED 1120 PM CDT TUE MAY 21 2013

MAIN CONCERN THIS FORECAST PERIOD WILL BE THE COVERAGE OF SHOWERS
AND ISOLATED TSRA OVERNIGHT AND INTO THE DAY ON WEDNESDAY AS AN
UPPER LEVEL WAVE DRIFTS ACRS THE REGION. OTHER THAN SOME ISOLATED
SHOWERS THAT MOVED ACRS THE AREA OVER THE PAST FEW HOURS THAT HAS
BEEN ABOUT IT RAIN-WISE. VFR CONDITIONS CONTINUE AND ARE EXPECTED
TO HOLD INTO AT LEAST WEDNESDAY MORNING BEFORE A SLOW MOVING COLD
FRONT TRACKS THRU THE TAF SITES BRINGING SOME SCATTERED SHOWERS
AND CIGS AT OR JUST ABOVE MVFR CAT. SATELLITE AND SFC OBS TO THE
NORTHWEST OF THE SFC LOW CURRENTLY OVER IOWA AND WISCONSIN SHOWING
A LARGE AREA OF MVFR CIGS AND IT APPEARS AS THE LOW SHIFTS OFF TO
OUR EAST BY LATER TOMORROW...SOME OF THOSE LOWER CIGS WILL SHIFT
SE INTO OUR AREA...ESPECIALLY TOMORROW NIGHT. FOR NOW...WILL KEEP
THE CIGS AT OR JUST ABOVE MVFR FOR NOW BUT MOST SITES MAY SEE
THE LOWER CIGS MOVE IN AFTR 00Z THU. SFC WINDS WILL REMAIN LIGHT
SSW TONIGHT AT 10 KTS OR LESS...AND THEN VEER MORE INTO A WESTERLY
DIRECTION ON WEDNESDAY AT 10 TO 15 KTS.

SMITH

&&

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

&&

$$