000
FXUS63 KILX 221716
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1216 PM CDT WED MAY 22 2013

.DISCUSSION...
ISSUED 1020 AM CDT WED MAY 22 2013

HAVE MADE SOME MINOR ALTERATIONS TO GOING FORECAST...PARTICULARLY
WITH RESPECT TO POPS TODAY.

AS BEST FORCING MOVES NORTHWARD OUT OF THE STATE LATE THIS MORNING
THE AREA OF SHOWERS AND THUNDERSTORMS SHOULD DIMINISH IN THE KPIA
AND KBMI AREA SHORTLY. HOWEVER WILL COOL MID-LEVEL TEMPS AROUND
-15C AT 500MB AND CONTINUED CYCLONIC FLOW...SCATTERED SHOWERS AND
THUNDERSTORMS WILL REDEVELOP BY EARLY AFTERNOON WITH THE STEEP
LOW-LEVEL LAPSE RATES.

LATEST LAMP DATA SUGGESTS CURRENT FORECASTED HIGHS REASONABLE.

BARKER
&&

.AVIATION...
ISSUED 1215 PM CDT WED MAY 22 2013

ALTHOUGH CLEAR SLOT NOW MOVING ACROSS CENTRAL IL TAF SITES...STEEP
LOW-LEVEL LAPSE RATES AND MESOSCALE MODELS SUGGEST THAT CLOUDS AND
SCT PCPN WILL DEVELOP QUICKLY THIS AFTERNOON. WILL HAVE AN HOUR
OR SO OF SCT CLDS AT KDEC AND KCMI BEFORE REDEVLOPMENT OF A CIG BY
19Z OR SO.

WEAK FRONT CURRENTLY MOVING ACROSS FORECAST AREA IS SHIFTING WINDS
FROM SW TO W...BUT HAS LITTLE ADDITIONAL IMPACT TO TERMINALS THIS AFTERNOON.

MAIN ENERGY ASSOCIATED WITH FILLING UPPER LOW OVER MID-MISSOURI
VALLEY SHOULD MOVE ACROSS ILLINOIS LATE TONIGHT FOLLOWED BY A
REINFORCING COLD FRONT. IMPACTS ON AREA AIRPORTS WILL INCLUDE
LOWERING CIGS OVERNIGHT WITH MVFR AND AREAS OF IFR DEVELOPING.
VSBYS SHOULD REMAIN UP GIVEN THE EXPECTED WIND SPEEDS MOSTLY IN
THE 08-15 KT RANGE. EXCEPTION MAY BE KDEC AND POSSIBLY KCMI WHERE
SOME 3SM VSBYS WILL BE POSSIBLE IN THE LIGHTER FORECAST WINDS BEFORE
THE FRONT PASSES TOMORROW MORNING.

BARKER
&&

.PREV 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 NORTH CENTRAL 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


&&

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

$$