000
FXUS63 KILX 181449
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
949 AM CDT SAT MAY 18 2013

.DISCUSSION...
ISSUED 949 AM CDT SAT MAY 18 2013

LITTLE CHANGE TO THE FORECASTS NEEDED THIS MORNING...ASIDE FROM
REMOVAL OF EARLIER FOG MENTION.

CLOUDS PIVOTING AROUND A SURFACE LOW IN WESTERN KENTUCKY THIS
MORNING. SO FAR THE SHOWERS HAVE REMAINED ACROSS INDIANA...BUT
SHOULD BEGIN TO SEE A FEW SHOWERS/STORMS POP UP ACROSS THE EASTERN
CWA OVER THE NEXT COUPLE HOURS AS THE DIURNAL HEATING PICKS UP.
TEMPERATURES LOOKING ON TRACK TO REACH THE LOWER 80S IN MOST
AREAS...BUT HAVE KEPT A FEW UPPER 70S IN THE FAR EASTERN CWA DUE
TO THE CLOUDS AND SHOWERS.

GEELHART

&&

.AVIATION...
ISSUED 619 AM CDT SAT MAY 18 2013

ALL SITES WILL START WITH IFR FOG AND POSSIBLY MVFR CIGS...FOR
FIRST COUPLE OF HOURS...THANKS TO THE RAIN THAT OCCURRED LAST
NIGHT AND THE HIGH DEW POINT AIR MASS THAT IS OVER THE AREA.
CONDITIONS WILL IMPROVE TO VFR BETWEEN 14 AND 15Z. SKY CONDITIONS
SHOULD BECOME CLEAR DURING THE EARLY EVENING HOURS. MOISTURE STILL
COULD BE AROUND TOMORROW MORNING SO HAVE ADDED A TEMPO GROUP FOR
SOME LIGHT FOG OVERNIGHT. WINDS WILL BE LIGHT AND VARIABLE THIS
MORNING BUT THEN BECOME SOUTHEASTERLY AT ALL SITES THIS MORNING
THROUGH AFTERNOON...THEN LIGHT AND VARIABLE AGAIN OVERNIGHT.

AUTEN
&&

.PREV DISCUSSION...
ISSUED 330 AM CDT SAT MAY 18 2013

SHORT TERM...TODAY THROUGH TUESDAY NIGHT

WILL CONTINUE PATCHY FOG ACROSS CENTRAL AND SOUTHEAST IL INTO MID
MORNING. LINGERING UPPER LEVEL TROF OVER THE OHIO VALLEY AND
DAYTIME HEATING WITH LINGERING MOISTURE WILL CONTINUE TO BRING A
CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS TO EASTERN IL BY LATE
MORNING AND AFTERNOON. HIGHS IN THE UPPER 70S AND LOWER 80S AND
COOLEST AROUND PARIS...MATTOON/CHARLESTON AND EFFINGHAM AREAS.
ISOLATED SHOWERS POSSIBLE UNTIL SUNDAY OVER THE WABASH RIVER
VALLEY OTHERWISE DRY TONIGHT WITH LOWER IN THE LOWER 60S AND COOLEST
BY DANVILLE AND PARIS. UPPER LEVEL RIDGE NOSING INTO IL SUNDAY
ALONG WITH WARM FRONT LIFTING NORTHWARD THROUGH IL TO BRING WARMER
AND MORE HUMID CONDITIONS WITH HIGHS IN THE MID TO UPPER 80S AND
DEWPOINTS IN THE MID TO UPPER 60S. HAVE 20-40% CHANCE OF SHOWERS
AND THUNDERSTORMS OVER THE IL RIVER VALLEY...WITH BEST CHANCES
SUNDAY AFTERNOON NW OF THE IL RIVER. STRONG LOW PRESSURE OVER THE
CENTRAL PLAINS WHERE BEST CHANCES OF SEVERE STORMS (15% RISK SEVERE)
WILL BE WEST OF IL SUNDAY/SUNDAY NIGHT...THOUGH SPC EXTENDS A
SLIGHT RISK AREA INTO THE IL RIVER VALLEY SUNDAY NIGHT AS SOME
SHORT WAVES PIVOT INTO THAT REGION BY SUNDAY EVENING.

SPC HAS ENTIRE AREA IN A SLIGHT RISK MONDAY AFTERNOON/EVENING WITH
15% RISK OF LARGE HAIL AND DAMAGING WIND GUSTS. CUTOFF AND SURFACE
LOW OVER NORTHERN PLAINS MONDAY AND AGAIN TUE WITH WARM/MOIST
AIR MASS OVER CENTRAL/SE IL AND SOME STRONG OR EVEN SEVERE STORMS
POSSIBLE AGAIN TUE AFTERNOON/TUE NIGHT. NUDGED MONDAY HIGHS A BIT
WARMER IN THE MID TO UPPER 80S. HIGHS TUE 80-85F EAST OF THE IL
RIVER AND UPPER 70S WEST OF THE IL RIVER.

LONG TERM...WEDNESDAY THROUGH SATURDAY

MODELS HAVE SURFACE AND UPPER LEVEL LOW PROGRESSING EASTWARD TOWARD
NORTHERN IL/SOUTHERN WI WED AND LIKELY BRINGING SHOWERS AND
THUNDERSTORMS TO REGION TUE AFTERNOON THROUGH WED. STRONGEST
STORMS WED APPEARS TO BE OVER EASTERN/SE IL OR INTO INDIANA DEPENDING
ON SPEED OF STORM SYSTEM. LINGERING CHANCES OF SHOWERS AND
ISOLATED THUNDERSTORMS WED NIGHT AND THU WITH UPPER LEVEL TROF
MOVING INTO IL...THEN TRENDING DRIER LATER NEXT WEEK. COOLER TEMPS
EXPECTED DURING THE SECOND HALF OF NEXT WEEK WITH HIGHS IN THE LOW
TO MID 70S FROM THU THROUGH SAT.

07

&&

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

$$

000
FXUS63 KILX 181119
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
619 AM CDT SAT MAY 18 2013

.DISCUSSION...
ISSUED 330 AM CDT SAT MAY 18 2013

SHORT TERM...TODAY THROUGH TUESDAY NIGHT

WILL CONTINUE PATCHY FOG ACROSS CENTRAL AND SOUTHEAST IL INTO MID
MORNING. LINGERING UPPER LEVEL TROF OVER THE OHIO VALLEY AND
DAYTIME HEATING WITH LINGERING MOISTURE WILL CONTINUE TO BRING A
CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS TO EASTERN IL BY LATE
MORNING AND AFTERNOON. HIGHS IN THE UPPER 70S AND LOWER 80S AND
COOLEST AROUND PARIS...MATTOON/CHARLESTON AND EFFINGHAM AREAS.
ISOLATED SHOWERS POSSIBLE UNTIL SUNDAY OVER THE WABASH RIVER
VALLEY OTHERWISE DRY TONIGHT WITH LOWER IN THE LOWER 60S AND COOLEST
BY DANVILLE AND PARIS. UPPER LEVEL RIDGE NOSING INTO IL SUNDAY
ALONG WITH WARM FRONT LIFTING NORTHWARD THROUGH IL TO BRING WARMER
AND MORE HUMID CONDITIONS WITH HIGHS IN THE MID TO UPPER 80S AND
DEWPOINTS IN THE MID TO UPPER 60S. HAVE 20-40% CHANCE OF SHOWERS
AND THUNDERSTORMS OVER THE IL RIVER VALLEY...WITH BEST CHANCES
SUNDAY AFTERNOON NW OF THE IL RIVER. STRONG LOW PRESSURE OVER THE
CENTRAL PLAINS WHERE BEST CHANCES OF SEVERE STORMS (15% RISK SEVERE)
WILL BE WEST OF IL SUNDAY/SUNDAY NIGHT...THOUGH SPC EXTENDS A
SLIGHT RISK AREA INTO THE IL RIVER VALLEY SUNDAY NIGHT AS SOME
SHORT WAVES PIVOT INTO THAT REGION BY SUNDAY EVENING.

SPC HAS ENTIRE AREA IN A SLIGHT RISK MONDAY AFTERNOON/EVENING WITH
15% RISK OF LARGE HAIL AND DAMAGING WIND GUSTS. CUTOFF AND SURFACE
LOW OVER NORTHERN PLAINS MONDAY AND AGAIN TUE WITH WARM/MOIST
AIRMASS OVER CENTRAL/SE IL AND SOME STRONG OR EVEN SEVERE STORMS
POSSIBLE AGAIN TUE AFTERNOON/TUE NIGHT. NUDGED MONDAY HIGHS A BIT
WARMER IN THE MID TO UPPER 80S. HIGHS TUE 80-85F EAST OF THE IL
RIVER AND UPPER 70S WEST OF THE IL RIVER.

LONG TERM...WEDNESDAY THROUGH SATURDAY

MODELS HAVE SURFACE AND UPPER LEVEL LOW PROGRESSING EASTWARD TOWARD
NORTHERN IL/SOUTHERN WI WED AND LIKELY BRINGING SHOWERS AND
THUNDERSTORMS TO REGION TUE AFTERNOON THROUGH WED. STRONGEST
STORMS WED APPEARS TO BE OVER EASTERN/SE IL OR INTO INDIANA DEPENDING
ON SPEED OF STORM SYSTEM. LINGERING CHANCES OF SHOWERS AND
ISOLATED THUNDERSTORMS WED NIGHT AND THU WITH UPPER LEVEL TROF
MOVING INTO IL...THEN TRENDING DRIER LATER NEXT WEEK. COOLER TEMPS
EXPECTED DURING THE SECOND HALF OF NEXT WEEK WITH HIGHS IN THE LOW
TO MID 70S FROM THU THROUGH SAT.

07
&&

.AVIATION...
ISSUED 619 AM CDT SAT MAY 18 2013

ALL SITES WILL START WITH IFR FOG AND POSSIBLY MVFR CIGS...FOR
FIRST COUPLE OF HOURS...THANKS TO THE RAIN THAT OCCURRED LAST
NIGHT AND THE HIGH DEWPOINT AIRMASS THAT IS OVER THE AREA.
CONDITIONS WILL IMPROVE TO VFR BETWEEN 14 AND 15Z. SKY CONDITIONS
SHOULD BECOME CLEAR DURING THE EARLY EVENING HOURS. MOISTURE STILL
COULD BE AROUND TOMORROW MORNING SO HAVE ADDED A TEMPO GROUP FOR
SOME LIGHT FOG OVERNIGHT. WINDS WILL BE LIGHT AND VARIABLE THIS
MORNING BUT THEN BECOME SOUTHEASTERLY AT ALL SITES THIS MORNING
THROUGH AFTERNOON...THEN LIGHT AND VARIABLE AGAIN OVERNIGHT.

AUTEN
&&

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

$$

000
FXUS63 KILX 180830
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
330 AM CDT SAT MAY 18 2013

.DISCUSSION...
ISSUED 330 AM CDT SAT MAY 18 2013

SHORT TERM...TODAY THROUGH TUESDAY NIGHT

WILL CONTINUE PATCHY FOG ACROSS CENTRAL AND SOUTHEAST IL INTO MID
MORNING. LINGERING UPPER LEVEL TROF OVER THE OHIO VALLEY AND
DAYTIME HEATING WITH LINGERING MOISTURE WILL CONTINUE TO BRING A
CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS TO EASTERN IL BY LATE
MORNING AND AFTERNOON. HIGHS IN THE UPPER 70S AND LOWER 80S AND
COOLEST AROUND PARIS...MATTOON/CHARLESTON AND EFFINGHAM AREAS.
ISOLATED SHOWERS POSSIBLE UNTIL SUNDAY OVER THE WABASH RIVER
VALLEY OTHERWISE DRY TONIGHT WITH LOWER IN THE LOWER 60S AND COOLEST
BY DANVILLE AND PARIS. UPPER LEVEL RIDG NOSING INTO IL SUNDAY
ALONG WITH WARM FRONT LIFTING NORTHWARD THROUGH IL TO BRING WARMER
AND MORE HUMID CONDITIONS WITH HIGHS IN THE MID TO UPPER 80S AND
DEWPOINTS IN THE MID TO UPPER 60S. HAVE 20-40% CHANCE OF SHOWERS
AND THUNDERSTORMS OVER THE IL RIVER VALLEY...WITH BEST CHANCES
SUNDAY AFTERNOON NW OF THE IL RIVER. STRONG LOW PRESSURE OVER THE
CENTRAL PLAINS WHERE BEST CHANCES OF SEVERE STORMS (15% RISK SEVERE)
WILL BE WEST OF IL SUNDAY/SUNDAY NIGHT...THOUGH SPC EXTENDS A
SLIGHT RISK AREA INTO THE IL RIVER VALLEY SUNDAY NIGHT AS SOME
SHORT WAVES PIVOT INTO THAT REGION BY SUNDAY EVENING.

SPC HAS ENTIRE AREA IN A SLIGHT RISK MONDAY AFTERNOON/EVENING WITH
15% RISK OF LARGE HAIL AND DAMAGING WIND GUSTS. CUTOFF AND SURFACE
LOW OVER NORTHERN PLAINS MONDAY AND AGAIN TUE WITH WARM/MOIST
AIRMASS OVER CENTRAL/SE IL AND SOME STRONG OR EVEN SEVERE STORMS
POSSIBLE AGAIN TUE AFTERNOON/TUE NIGHT. NUDGED MONDAY HIGHS A BIT
WARMER IN THE MID TO UPPER 80S. HIGHS TUE 80-85F EAST OF THE IL
RIVER AND UPPER 70S WEST OF THE IL RIVER.

LONG TERM...WEDNESDAY THROUGH SATURDAY

MODELS HAVE SURFACE AND UPPER LEVEL LOW PROGESSING EASTWARD TOWARD
NORTHERN IL/SOUTHERN WI WED AND LIKELY BRINGING SHOWERS AND
THUNDERSTORMS TO REGION TUE AFTERNOON THROUGH WED. STRONGEST
STORMS WED APPEARS TO BE OVER EASTERN/SE IL OR INTO INDIANA DEPENDING
ON SPEED OF STORM SYSTEM. LINGERING CHANCES OF SHOWERS AND
ISOLATED THUNDERSTORMS WED NIGHT AND THU WITH UPPER LEVEL TROF
MOVING INTO IL...THEN TRENDING DRIER LATER NEXT WEEK. COOLER TEMPS
EXPECTED DURING THE SECOND HALF OF NEXT WEEK WITH HIGHS IN THE LOW
TO MID 70S FROM THU THROUGH SAT.

07

&&

.AVIATION...
ISSUED 1137 PM CDT FRI MAY 17 2013

PERSISTENT CLUSTER OF SHOWERS NEAR KPIA WILL GRADUALLY DISSIPATE
BY 06Z...HOWEVER WILL MAINTAIN VCSH THROUGH 08Z IN CASE A FEW
SHOWERS LINGER. WITH LIGHT WINDS AND PLENTY OF LOW-LEVEL MOISTURE IN
PLACE...PARTIAL CLEARING OVERNIGHT WILL LEAD TO THE DEVELOPMENT OF
PATCHY FOG. BIG QUESTION WILL BE WHETHER OR NOT A LOW OVERCAST
WILL FORM AS WELL. NAM FORECAST SOUNDINGS ARE SUGGESTING CEILINGS
OF AROUND 1000FT OVERNIGHT INTO EARLY SATURDAY MORNING. THINK THIS
IS OVERDONE AND WILL ONLY INCLUDE SCT CLOUD COVER AROUND 1500FT
ALONG WITH 2-4SM FOG OVERNIGHT. ONCE THE MORNING FOG/CLOUDS
LIFT...NEGATIVE CU-RULE POINTS TO A PARTLY SUNNY DAY WITH CLOUD
BASES AROUND 5000FT. WILL INCLUDE VCSH AT KCMI IN CLOSER PROXIMITY
TO UPPER LOW SPINNING OVER THE OHIO RIVER VALLEY. WINDS WILL BE
E/SE AT 10KT OR LESS THROUGH THE ENTIRE 06Z TAF PERIOD.

BARNES
&&

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

$$

000
FXUS63 KILX 180437
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1137 PM CDT FRI MAY 17 2013

.DISCUSSION...
ISSUED 830 PM CDT FRI MAY 17 2013

01Z/8PM RADAR IMAGERY SHOWS ISOLATED SHOWERS ALONG/NORTHWEST OF A
PETERSBURG TO BLOOMINGTON-NORMAL LINE. THESE SHOWERS WILL CONTINUE
TO DRIFT SLOWLY NORTHWARD BEFORE DISSIPATING BY AROUND 10PM. AFTER
THAT...DRY WEATHER IS ANTICIPATED OVERNIGHT. WITH MOIST DEWPOINTS
IN THE LOWER TO MIDDLE 60S AND VERY LIGHT WINDS...EXPECT FOG TO
DEVELOP AFTER MIDNIGHT. HRRR SUGGESTS VISBYS MAY DROP TO 1SM OR
LESS TOWARD DAWN...HOWEVER THINK THIS MAY BE A BIT TOO AGGRESSIVE
GIVEN THE AMOUNT OF CLOUD COVER THAT SHOULD BE STICKING AROUND. AT
THIS POINT...WILL JUST CARRY PATCHY FOG OVERNIGHT. ZONE UPDATE HAS
ALREADY BEEN ISSUED.



&&

.AVIATION...
ISSUED 1137 PM CDT FRI MAY 17 2013

PERSISTENT CLUSTER OF SHOWERS NEAR KPIA WILL GRADUALLY DISSIPATE
BY 06Z...HOWEVER WILL MAINTAIN VCSH THROUGH 08Z IN CASE A FEW
SHOWERS LINGER. WITH LIGHT WINDS AND PLENTY OF LOW-LEVEL MOISTURE IN
PLACE...PARTIAL CLEARING OVERNIGHT WILL LEAD TO THE DEVELOPMENT OF
PATCHY FOG. BIG QUESTION WILL BE WHETHER OR NOT A LOW OVERCAST
WILL FORM AS WELL. NAM FORECAST SOUNDINGS ARE SUGGESTING CEILINGS
OF AROUND 1000FT OVERNIGHT INTO EARLY SATURDAY MORNING. THINK THIS
IS OVERDONE AND WILL ONLY INCLUDE SCT CLOUD COVER AROUND 1500FT
ALONG WITH 2-4SM FOG OVERNIGHT. ONCE THE MORNING FOG/CLOUDS
LIFT...NEGATIVE CU-RULE POINTS TO A PARTLY SUNNY DAY WITH CLOUD
BASES AROUND 5000FT. WILL INCLUDE VCSH AT KCMI IN CLOSER PROXIMITY
TO UPPER LOW SPINNING OVER THE OHIO RIVER VALLEY. WINDS WILL BE
E/SE AT 10KT OR LESS THROUGH THE ENTIRE 06Z TAF PERIOD.


BARNES
&&

.PREV DISCUSSION...
ISSUED 300 PM CDT FRI MAY 17 2013

AN EXTENDED PERIOD OF RAIN CHANCES WILL CONTINUE INTO THE WEEKEND
AND MOST OF NEXT WEEK. THE MAIN WEATHER FEATURES WILL BE A
STATIONARY FRONT AND UPPER LOW THE REST OF TODAY AND
SATURDAY...THEN A WARM FRONT ACROSS IL AND DEEPENING LOW PRESSURE
IN THE PLAINS ON SUNDAY AND MONDAY...THEN A SLOW MOVING OCCLUDED
LOW MONDAY NIGHT THROUGH TUESDAY NIGHT...BEFORE A COLD FRONT
FINALLY PUSHES ACROSS ILLINOIS ON WEDNESDAY.

THE BEST WINDOW OF OPPORTUNITY FOR ANY LONGER BREAKS IN THE RAIN
MAY BE SATURDAY AND SUNDAY...BUT STRONG INSTABILITY AS THE CAP
ERODES LATE SUNDAY AFTERNOON INTO SUNDAY EVENING MAY ALLOW FOR
STRONG TO SEVERE STORMS SUNDAY NIGHT NORTHWEST OF THE IL RIVER.

SHORT TERM...TONIGHT THROUGH MONDAY NIGHT.

SHOWERS AND THUNDERSTORMS ERUPTED THIS AFTERNOON AS THE CAP
DISSIPATED...BUT COVERAGE WAS ISOLATED FOR THE MOST PART. THE
PRIMARY AREA OF ACTIVITY IN OUR AREA WAS FROM GALESBURG TO
HOOPESTON...CLOSER TO THE STATIONARY FRONT THAT EXTENDED ACROSS
NORTHERN IL. ADDITIONAL SHOWERS DEVELOPED FARTHER SOUTH FROM
JACKSONVILLE TO LAWRENCEVILLE ASSOCIATED WITH THE UPPER LOW MOVING
EAST INTO KENTUCKY. THE FRONT AND LOW WILL CONTINUE TO TRIGGER
SHOWERS AND STORMS INTO THE EVENING...BUT PROGRESSIVELY EAST WITH
TIME. BY MIDNIGHT...WE EXPECT PRECIP TO COME TO AN END IN CENTRAL
IL.

MOST OF THE DAY ON SATURDAY SHOULD BE DRY...BUT WE CAN NOT RULE
OUT SOME DIURNAL SHOWERS AND ISOLATED STORMS EAST OF I-57 AS THE
UPPER LOW LINGERS NEARBY TO THE EAST OF IL. A LULL IN THE RAIN
LOOKS LIKELY SATURDAY NIGHT AND MUCH OF SUNDAY...AS WARM AIR
SURGES INTO THE AREA. DEWPOINTS ON SUNDAY WILL CLIMB INTO THE
LOWER 70S AS HIGH TEMPS REACH THE UPPER 80S. A LOW LEVEL INVERSION
WILL PROVIDE A CAP UNTIL LATE IN THE DAY ON SUNDAY. ELEVATED
INSTABILITY WILL INCREASE DRAMATICALLY BY LATE AFTERNOON...WITH ML
CAPE VALUES AROUND 4K J/KG AND LI`S OF -10C. THE CAP WILL ERODE
FROM WEST TO EAST...REACHING PEORIA TO SPI BY 6-7 PM. SO OUR
WESTERN COUNTIES WILL HAVE THE BEST CHANCES FOR STRONG TO SEVERE
STORMS SUNDAY EVENING. TONED DOWN STORMS ARE EXPECTED TO ADVANCE
EAST TOWARD I-57 AFTER MIDNIGHT SUNDAY NIGHT.

MONDAY LOOKS TO BE LESS LIKELY FOR STORMS THAN PREVIOUS FORECAST
MODEL SOLUTIONS INDICATED. CLOUD COVER WILL KEEP HIGH TEMPS IN THE
LOWER 80S...BUT WE WILL REMAIN IN THE WARM SECTOR. WE REMOVED ANY
LIKELY POPS FROM MONDAY AND KEPT CHANCE POPS ACROSS THE AREA.
INSTABILITY PARAMS BECOME FAVORABLE AGAIN FOR STRONG STORMS MONDAY
EVENING...AS WE BREAK THE INVERSION AGAIN...BUT WE ARE NOT IN THE
SPC DAY 4 OUTLOOK FOR MON-MON NIGHT LIKE WE WERE IN THE DAY 5
OUTLOOK YESTERDAY. LACK OF A SOLID FOCUSING MECHANISM IS ONE OF
THE REASONS WHY. THE WARM FRONT WILL BE NORTH OF OUR AREA...AND
THE OCCLUDED LOW AND ITS ENERGY WILL BE MAINLY IN THE NORTHERN
PLAINS.

LONG TERM...TUESDAY THROUGH FRIDAY.

AS THE OCCLUDED LOW MOVES TOWARD IL ON TUESDAY...AND SETTLES OVER
N-NW IL TUESDAY NIGHT COVERAGE OF SHOWERS AND STORMS WILL BECOME
MORE WIDESPREAD. LIKELY POPS WERE INCLUDED EVERYWHERE BUT THE FAR
WESTERN COUNTIES TUESDAY AND TUESDAY NIGHT...WITH LOCALLY HEAVY
RAINFALL POSSIBLE AS STORM MOTIONS REMAIN SLOW.

THE COLD FRONT WILL EVENTUALLY MOVE ACROSS OUR AREA ON WEDNESDAY
AS THE LOW PRESSURE SYSTEM FINALLY PULLS AWAY TO THE NORTHEAST.
DRIER CONDITIONS WILL BEGIN TO RETURN WED NIGHT...BUT THE COLD
POOL ALOFT WILL KEEP CHANCES OF INSTABILITY SHOWERS IN PLACE FOR
THURSDAY.

THE COLDEST AIR OF THE WEEK WILL COME THURSDAY THROUGH FRIDAY...AS
HIGHS ONLY REACH THE LOW TO MID 70S...AND LOWS DIP INTO THE 50S.
SUNSHINE AND DRY CONDITIONS RETURN FOR FRIDAY...FINALLY.


&&

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

$$

000
FXUS63 KILX 180130
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
830 PM CDT FRI MAY 17 2013

.DISCUSSION...
ISSUED 830 PM CDT FRI MAY 17 2013

01Z/8PM RADAR IMAGERY SHOWS ISOLATED SHOWERS ALONG/NORTHWEST OF A
PETERSBURG TO BLOOMINGTON-NORMAL LINE. THESE SHOWERS WILL CONTINUE
TO DRIFT SLOWLY NORTHWARD BEFORE DISSIPATING BY AROUND 10PM. AFTER
THAT...DRY WEATHER IS ANTICIPATED OVERNIGHT. WITH MOIST DEWPOINTS
IN THE LOWER TO MIDDLE 60S AND VERY LIGHT WINDS...EXPECT FOG TO
DEVELOP AFTER MIDNIGHT. HRRR SUGGESTS VISBYS MAY DROP TO 1SM OR
LESS TOWARD DAWN...HOWEVER THINK THIS MAY BE A BIT TOO AGGRESSIVE
GIVEN THE AMOUNT OF CLOUD COVER THAT SHOULD BE STICKING AROUND. AT
THIS POINT...WILL JUST CARRY PATCHY FOG OVERNIGHT. ZONE UPDATE HAS
ALREADY BEEN ISSUED.

BARNES
&&

.AVIATION...
ISSUED 644 PM CDT FRI MAY 17 2013

SCATTERED SHOWERS WILL CONTINUE TO DEVELOP AND DRIFT NORTHWARD
OVER THE NEXT COUPLE OF HOURS...BEFORE DISSIPATING AFTER SUNSET.
WILL CARRY VCSH AT ALL TERMINALS BETWEEN 00Z AND 03Z ACCORDINGLY.
WITH LIGHT WINDS AND PLENTY OF LOW-LEVEL MOISTURE IN
PLACE...PARTIAL CLEARING OVERNIGHT WILL LEAD TO THE DEVELOPMENT OF
PATCHY FOG. BIG QUESTION WILL BE WHETHER OR NOT A LOW OVERCAST
WILL FORM AS WELL. NAM FORECAST SOUNDINGS ARE SUGGESTING CEILINGS
OF AROUND 1000FT OVERNIGHT INTO EARLY SATURDAY MORNING. THINK THIS
IS OVERDONE AND WILL ONLY INCLUDE SCT CLOUD COVER AROUND 1500FT
ALONG WITH 2-4SM FOG OVERNIGHT. ONCE THE MORNING FOG/CLOUDS
LIFT...NEGATIVE CU-RULE POINTS TO A PARTLY SUNNY DAY WITH CLOUD
BASES AROUND 5000FT. WINDS WILL INITIALLY BE SOUTHERLY EARLY THIS
EVENING...THEN WILL BACK TO E/SE LATER TONIGHT INTO SATURDAY

BARNES
&&

.PREV DISCUSSION...
ISSUED 300 PM CDT FRI MAY 17 2013

AN EXTENDED PERIOD OF RAIN CHANCES WILL CONTINUE INTO THE WEEKEND
AND MOST OF NEXT WEEK. THE MAIN WEATHER FEATURES WILL BE A
STATIONARY FRONT AND UPPER LOW THE REST OF TODAY AND
SATURDAY...THEN A WARM FRONT ACROSS IL AND DEEPENING LOW PRESSURE
IN THE PLAINS ON SUNDAY AND MONDAY...THEN A SLOW MOVING OCCLUDED
LOW MONDAY NIGHT THROUGH TUESDAY NIGHT...BEFORE A COLD FRONT
FINALLY PUSHES ACROSS ILLINOIS ON WEDNESDAY.

THE BEST WINDOW OF OPPORTUNITY FOR ANY LONGER BREAKS IN THE RAIN
MAY BE SATURDAY AND SUNDAY...BUT STRONG INSTABILITY AS THE CAP
ERODES LATE SUNDAY AFTERNOON INTO SUNDAY EVENING MAY ALLOW FOR
STRONG TO SEVERE STORMS SUNDAY NIGHT NORTHWEST OF THE IL RIVER.

SHORT TERM...TONIGHT THROUGH MONDAY NIGHT.

SHOWERS AND THUNDERSTORMS ERUPTED THIS AFTERNOON AS THE CAP
DISSIPATED...BUT COVERAGE WAS ISOLATED FOR THE MOST PART. THE
PRIMARY AREA OF ACTIVITY IN OUR AREA WAS FROM GALESBURG TO
HOOPESTON...CLOSER TO THE STATIONARY FRONT THAT EXTENDED ACROSS
NORTHERN IL. ADDITIONAL SHOWERS DEVELOPED FARTHER SOUTH FROM
JACKSONVILLE TO LAWRENCEVILLE ASSOCIATED WITH THE UPPER LOW MOVING
EAST INTO KENTUCKY. THE FRONT AND LOW WILL CONTINUE TO TRIGGER
SHOWERS AND STORMS INTO THE EVENING...BUT PROGRESSIVELY EAST WITH
TIME. BY MIDNIGHT...WE EXPECT PRECIP TO COME TO AN END IN CENTRAL
IL.

MOST OF THE DAY ON SATURDAY SHOULD BE DRY...BUT WE CAN NOT RULE
OUT SOME DIURNAL SHOWERS AND ISOLATED STORMS EAST OF I-57 AS THE
UPPER LOW LINGERS NEARBY TO THE EAST OF IL. A LULL IN THE RAIN
LOOKS LIKELY SATURDAY NIGHT AND MUCH OF SUNDAY...AS WARM AIR
SURGES INTO THE AREA. DEWPOINTS ON SUNDAY WILL CLIMB INTO THE
LOWER 70S AS HIGH TEMPS REACH THE UPPER 80S. A LOW LEVEL INVERSION
WILL PROVIDE A CAP UNTIL LATE IN THE DAY ON SUNDAY. ELEVATED
INSTABILITY WILL INCREASE DRAMATICALLY BY LATE AFTERNOON...WITH ML
CAPE VALUES AROUND 4K J/KG AND LI`S OF -10C. THE CAP WILL ERODE
FROM WEST TO EAST...REACHING PEORIA TO SPI BY 6-7 PM. SO OUR
WESTERN COUNTIES WILL HAVE THE BEST CHANCES FOR STRONG TO SEVERE
STORMS SUNDAY EVENING. TONED DOWN STORMS ARE EXPECTED TO ADVANCE
EAST TOWARD I-57 AFTER MIDNIGHT SUNDAY NIGHT.

MONDAY LOOKS TO BE LESS LIKELY FOR STORMS THAN PREVIOUS FORECAST
MODEL SOLUTIONS INDICATED. CLOUD COVER WILL KEEP HIGH TEMPS IN THE
LOWER 80S...BUT WE WILL REMAIN IN THE WARM SECTOR. WE REMOVED ANY
LIKELY POPS FROM MONDAY AND KEPT CHANCE POPS ACROSS THE AREA.
INSTABILITY PARAMS BECOME FAVORABLE AGAIN FOR STRONG STORMS MONDAY
EVENING...AS WE BREAK THE INVERSION AGAIN...BUT WE ARE NOT IN THE
SPC DAY 4 OUTLOOK FOR MON-MON NIGHT LIKE WE WERE IN THE DAY 5
OUTLOOK YESTERDAY. LACK OF A SOLID FOCUSING MECHANISM IS ONE OF
THE REASONS WHY. THE WARM FRONT WILL BE NORTH OF OUR AREA...AND
THE OCCLUDED LOW AND ITS ENERGY WILL BE MAINLY IN THE NORTHERN
PLAINS.

LONG TERM...TUESDAY THROUGH FRIDAY.

AS THE OCCLUDED LOW MOVES TOWARD IL ON TUESDAY...AND SETTLES OVER
N-NW IL TUESDAY NIGHT COVERAGE OF SHOWERS AND STORMS WILL BECOME
MORE WIDESPREAD. LIKELY POPS WERE INCLUDED EVERYWHERE BUT THE FAR
WESTERN COUNTIES TUESDAY AND TUESDAY NIGHT...WITH LOCALLY HEAVY
RAINFALL POSSIBLE AS STORM MOTIONS REMAIN SLOW.

THE COLD FRONT WILL EVENTUALLY MOVE ACROSS OUR AREA ON WEDNESDAY
AS THE LOW PRESSURE SYSTEM FINALLY PULLS AWAY TO THE NORTHEAST.
DRIER CONDITIONS WILL BEGIN TO RETURN WED NIGHT...BUT THE COLD
POOL ALOFT WILL KEEP CHANCES OF INSTABILITY SHOWERS IN PLACE FOR
THURSDAY.

THE COLDEST AIR OF THE WEEK WILL COME THURSDAY THROUGH FRIDAY...AS
HIGHS ONLY REACH THE LOW TO MID 70S...AND LOWS DIP INTO THE 50S.
SUNSHINE AND DRY CONDITIONS RETURN FOR FRIDAY...FINALLY.

&&

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

$$

000
FXUS63 KILX 172344
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
644 PM CDT FRI MAY 17 2013

.DISCUSSION...
ISSUED 300 PM CDT FRI MAY 17 2013

AN EXTENDED PERIOD OF RAIN CHANCES WILL CONTINUE INTO THE WEEKEND
AND MOST OF NEXT WEEK. THE MAIN WEATHER FEATURES WILL BE A
STATIONARY FRONT AND UPPER LOW THE REST OF TODAY AND
SATURDAY...THEN A WARM FRONT ACROSS IL AND DEEPENING LOW PRESSURE
IN THE PLAINS ON SUNDAY AND MONDAY...THEN A SLOW MOVING OCCLUDED
LOW MONDAY NIGHT THROUGH TUESDAY NIGHT...BEFORE A COLD FRONT
FINALLY PUSHES ACROSS ILLINOIS ON WEDNESDAY.

THE BEST WINDOW OF OPPORTUNITY FOR ANY LONGER BREAKS IN THE RAIN
MAY BE SATURDAY AND SUNDAY...BUT STRONG INSTABILITY AS THE CAP
ERODES LATE SUNDAY AFTERNOON INTO SUNDAY EVENING MAY ALLOW FOR
STRONG TO SEVERE STORMS SUNDAY NIGHT NORTHWEST OF THE IL RIVER.

SHORT TERM...TONIGHT THROUGH MONDAY NIGHT.

SHOWERS AND THUNDERSTORMS ERUPTED THIS AFTERNOON AS THE CAP
DISSIPATED...BUT COVERAGE WAS ISOLATED FOR THE MOST PART. THE
PRIMARY AREA OF ACTIVITY IN OUR AREA WAS FROM GALESBURG TO
HOOPESTON...CLOSER TO THE STATIONARY FRONT THAT EXTENDED ACROSS
NORTHERN IL. ADDITIONAL SHOWERS DEVELOPED FARTHER SOUTH FROM
JACKSONVILLE TO LAWRENCEVILLE ASSOCIATED WITH THE UPPER LOW MOVING
EAST INTO KENTUCKY. THE FRONT AND LOW WILL CONTINUE TO TRIGGER
SHOWERS AND STORMS INTO THE EVENING...BUT PROGRESSIVELY EAST WITH
TIME. BY MIDNIGHT...WE EXPECT PRECIP TO COME TO AN END IN CENTRAL
IL.

MOST OF THE DAY ON SATURDAY SHOULD BE DRY...BUT WE CAN NOT RULE
OUT SOME DIURNAL SHOWERS AND ISOLATED STORMS EAST OF I-57 AS THE
UPPER LOW LINGERS NEARBY TO THE EAST OF IL. A LULL IN THE RAIN
LOOKS LIKELY SATURDAY NIGHT AND MUCH OF SUNDAY...AS WARM AIR
SURGES INTO THE AREA. DEWPOINTS ON SUNDAY WILL CLIMB INTO THE
LOWER 70S AS HIGH TEMPS REACH THE UPPER 80S. A LOW LEVEL INVERSION
WILL PROVIDE A CAP UNTIL LATE IN THE DAY ON SUNDAY. ELEVATED
INSTABILITY WILL INCREASE DRAMATICALLY BY LATE AFTERNOON...WITH ML
CAPE VALUES AROUND 4K J/KG AND LI`S OF -10C. THE CAP WILL ERODE
FROM WEST TO EAST...REACHING PEORIA TO SPI BY 6-7 PM. SO OUR
WESTERN COUNTIES WILL HAVE THE BEST CHANCES FOR STRONG TO SEVERE
STORMS SUNDAY EVENING. TONED DOWN STORMS ARE EXPECTED TO ADVANCE
EAST TOWARD I-57 AFTER MIDNIGHT SUNDAY NIGHT.

MONDAY LOOKS TO BE LESS LIKELY FOR STORMS THAN PREVIOUS FORECAST
MODEL SOLUTIONS INDICATED. CLOUD COVER WILL KEEP HIGH TEMPS IN THE
LOWER 80S...BUT WE WILL REMAIN IN THE WARM SECTOR. WE REMOVED ANY
LIKELY POPS FROM MONDAY AND KEPT CHANCE POPS ACROSS THE AREA.
INSTABILITY PARAMS BECOME FAVORABLE AGAIN FOR STRONG STORMS MONDAY
EVENING...AS WE BREAK THE INVERSION AGAIN...BUT WE ARE NOT IN THE
SPC DAY 4 OUTLOOK FOR MON-MON NIGHT LIKE WE WERE IN THE DAY 5
OUTLOOK YESTERDAY. LACK OF A SOLID FOCUSING MECHANISM IS ONE OF
THE REASONS WHY. THE WARM FRONT WILL BE NORTH OF OUR AREA...AND
THE OCCLUDED LOW AND ITS ENERGY WILL BE MAINLY IN THE NORTHERN
PLAINS.

LONG TERM...TUESDAY THROUGH FRIDAY.

AS THE OCCLUDED LOW MOVES TOWARD IL ON TUESDAY...AND SETTLES OVER
N-NW IL TUESDAY NIGHT COVERAGE OF SHOWERS AND STORMS WILL BECOME
MORE WIDESPREAD. LIKELY POPS WERE INCLUDED EVERYWHERE BUT THE FAR
WESTERN COUNTIES TUESDAY AND TUESDAY NIGHT...WITH LOCALLY HEAVY
RAINFALL POSSIBLE AS STORM MOTIONS REMAIN SLOW.

THE COLD FRONT WILL EVENTUALLY MOVE ACROSS OUR AREA ON WEDNESDAY
AS THE LOW PRESSURE SYSTEM FINALLY PULLS AWAY TO THE NORTHEAST.
DRIER CONDITIONS WILL BEGIN TO RETURN WED NIGHT...BUT THE COLD
POOL ALOFT WILL KEEP CHANCES OF INSTABILITY SHOWERS IN PLACE FOR
THURSDAY.

THE COLDEST AIR OF THE WEEK WILL COME THURSDAY THROUGH FRIDAY...AS
HIGHS ONLY REACH THE LOW TO MID 70S...AND LOWS DIP INTO THE 50S.
SUNSHINE AND DRY CONDITIONS RETURN FOR FRIDAY...FINALLY.



&&

.AVIATION...
ISSUED 644 PM CDT FRI MAY 17 2013

SCATTERED SHOWERS WILL CONTINUE TO DEVELOP AND DRIFT NORTHWARD
OVER THE NEXT COUPLE OF HOURS...BEFORE DISSIPATING AFTER SUNSET.
WILL CARRY VCSH AT ALL TERMINALS BETWEEN 00Z AND 03Z ACCORDINGLY.
WITH LIGHT WINDS AND PLENTY OF LOW-LEVEL MOISTURE IN
PLACE...PARTIAL CLEARING OVERNIGHT WILL LEAD TO THE DEVELOPMENT OF
PATCHY FOG. BIG QUESTION WILL BE WHETHER OR NOT A LOW OVERCAST
WILL FORM AS WELL. NAM FORECAST SOUNDINGS ARE SUGGESTING CEILINGS
OF AROUND 1000FT OVERNIGHT INTO EARLY SATURDAY MORNING. THINK THIS
IS OVERDONE AND WILL ONLY INCLUDE SCT CLOUD COVER AROUND 1500FT
ALONG WITH 2-4SM FOG OVERNIGHT. ONCE THE MORNING FOG/CLOUDS
LIFT...NEGATIVE CU-RULE POINTS TO A PARTLY SUNNY DAY WITH CLOUD
BASES AROUND 5000FT. WINDS WILL INITIALLY BE SOUTHERLY EARLY THIS
EVENING...THEN WILL BACK TO E/SE LATER TONIGHT INTO SATURDAY

BARNES
&&

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

$$

000
FXUS63 KILX 172004
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
304 PM CDT FRI MAY 17 2013

.DISCUSSION...
ISSUED 300 PM CDT FRI MAY 17 2013

AN EXTENDED PERIOD OF RAIN CHANCES WILL CONTINUE INTO THE WEEKEND
AND MOST OF NEXT WEEK. THE MAIN WEATHER FEATURES WILL BE A
STATIONARY FRONT AND UPPER LOW THE REST OF TODAY AND
SATURDAY...THEN A WARM FRONT ACROSS IL AND DEEPENING LOW PRESSURE
IN THE PLAINS ON SUNDAY AND MONDAY...THEN A SLOW MOVING OCCLUDED
LOW MONDAY NIGHT THROUGH TUESDAY NIGHT...BEFORE A COLD FRONT
FINALLY PUSHES ACROSS ILLINOIS ON WEDNESDAY.

THE BEST WINDOW OF OPPORTUNITY FOR ANY LONGER BREAKS IN THE RAIN
MAY BE SATURDAY AND SUNDAY...BUT STRONG INSTABILITY AS THE CAP
ERODES LATE SUNDAY AFTERNOON INTO SUNDAY EVENING MAY ALLOW FOR
STRONG TO SEVERE STORMS SUNDAY NIGHT NORTHWEST OF THE IL RIVER.

SHORT TERM...TONIGHT THROUGH MONDAY NIGHT.

SHOWERS AND THUNDERSTORMS ERUPTED THIS AFTERNOON AS THE CAP
DISSIPATED...BUT COVERAGE WAS ISOLATED FOR THE MOST PART. THE
PRIMARY AREA OF ACTIVITY IN OUR AREA WAS FROM GALESBURG TO
HOOPESTON...CLOSER TO THE STATIONARY FRONT THAT EXTENDED ACROSS
NORTHERN IL. ADDITIONAL SHOWERS DEVELOPED FARTHER SOUTH FROM
JACKSONVILLE TO LAWRENCEVILLE ASSOCIATED WITH THE UPPER LOW MOVING
EAST INTO KENTUCKY. THE FRONT AND LOW WILL CONTINUE TO TRIGGER
SHOWERS AND STORMS INTO THE EVENING...BUT PROGRESSIVELY EAST WITH
TIME. BY MIDNIGHT...WE EXPECT PRECIP TO COME TO AN END IN CENTRAL
IL.

MOST OF THE DAY ON SATURDAY SHOULD BE DRY...BUT WE CAN NOT RULE
OUT SOME DIURNAL SHOWERS AND ISOLATED STORMS EAST OF I-57 AS THE
UPPER LOW LINGERS NEARBY TO THE EAST OF IL. A LULL IN THE RAIN
LOOKS LIKELY SATURDAY NIGHT AND MUCH OF SUNDAY...AS WARM AIR
SURGES INTO THE AREA. DEWPOINTS ON SUNDAY WILL CLIMB INTO THE
LOWER 70S AS HIGH TEMPS REACH THE UPPER 80S. A LOW LEVEL INVERSION
WILL PROVIDE A CAP UNTIL LATE IN THE DAY ON SUNDAY. ELEVATED
INSTABILITY WILL INCREASE DRAMATICALLY BY LATE AFTERNOON...WITH ML
CAPE VALUES AROUND 4K J/KG AND LI`S OF -10C. THE CAP WILL ERODE
FROM WEST TO EAST...REACHING PEORIA TO SPI BY 6-7 PM. SO OUR
WESTERN COUNTIES WILL HAVE THE BEST CHANCES FOR STRONG TO SEVERE
STORMS SUNDAY EVENING. TONED DOWN STORMS ARE EXPECTED TO ADVANCE
EAST TOWARD I-57 AFTER MIDNIGHT SUNDAY NIGHT.

MONDAY LOOKS TO BE LESS LIKELY FOR STORMS THAN PREVIOUS FORECAST
MODEL SOLUTIONS INDICATED. CLOUD COVER WILL KEEP HIGH TEMPS IN THE
LOWER 80S...BUT WE WILL REMAIN IN THE WARM SECTOR. WE REMOVED ANY
LIKELY POPS FROM MONDAY AND KEPT CHANCE POPS ACROSS THE AREA.
INSTABILITY PARAMS BECOME FAVORABLE AGAIN FOR STRONG STORMS MONDAY
EVENING...AS WE BREAK THE INVERSION AGAIN...BUT WE ARE NOT IN THE
SPC DAY 4 OUTLOOK FOR MON-MON NIGHT LIKE WE WERE IN THE DAY 5
OUTLOOK YESTERDAY. LACK OF A SOLID FOCUSING MECHANISM IS ONE OF
THE REASONS WHY. THE WARM FRONT WILL BE NORTH OF OUR AREA...AND
THE OCCLUDED LOW AND ITS ENERGY WILL BE MAINLY IN THE NORTHERN
PLAINS.

LONG TERM...TUESDAY THROUGH FRIDAY.

AS THE OCCLUDED LOW MOVES TOWARD IL ON TUESDAY...AND SETTLES OVER
N-NW IL TUESDAY NIGHT COVERAGE OF SHOWERS AND STORMS WILL BECOME
MORE WIDESPREAD. LIKELY POPS WERE INCLUDED EVERYWHERE BUT THE FAR
WESTERN COUNTIES TUESDAY AND TUESDAY NIGHT...WITH LOCALLY HEAVY
RAINFALL POSSIBLE AS STORM MOTIONS REMAIN SLOW.

THE COLD FRONT WILL EVENTUALLY MOVE ACROSS OUR AREA ON WEDNESDAY
AS THE LOW PRESSURE SYSTEM FINALLY PULLS AWAY TO THE NORTHEAST.
DRIER CONDITIONS WILL BEGIN TO RETURN WED NIGHT...BUT THE COLD
POOL ALOFT WILL KEEP CHANCES OF INSTABILITY SHOWERS IN PLACE FOR
THURSDAY.

THE COLDEST AIR OF THE WEEK WILL COME THURSDAY THROUGH FRIDAY...AS
HIGHS ONLY REACH THE LOW TO MID 70S...AND LOWS DIP INTO THE 50S.
SUNSHINE AND DRY CONDITIONS RETURN FOR FRIDAY...FINALLY.

SHIMON
&&

.AVIATION...
ISSUED 1220 PM CDT FRI MAY 17 2013

SCATTERED CONVECTION HAS BEEN INCREASING OVER THE LAST COUPLE
HOURS AND WAS MOVING NORTHWARD. POP-UP NATURE AGAIN PRECLUDES
MENTION OF MORE THAN VCTS UNLESS THE STORMS BECOME MORE
ORGANIZED...AT WHICH POINT TAF AMENDMENTS WILL BE USED TO TIME ANY
PREVAILING TSRA MENTIONS. STORMS SHOULD FADE AWAY WITH SUNSET.
OVERNIGHT CONCERN WILL BE WITH MVFR/IFR POTENTIAL. SREF
PROBABILITIES FAVOR THESE CONDITIONS ADVECTING NORTHWARD OUT OF
SOUTHERN ILLINOIS AFTER 06Z AS WINDS WILL BE LIGHTER DOWN THERE...
BUT PLACEMENT OF ANY HEAVIER RAIN TODAY WILL ALSO PLAY A ROLE.
HAVE MADE LITTLE CHANGES FROM PREVIOUS TAF SET FOR NOW IN THIS
REGARD.

GEELHART
&&

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

$$

000
FXUS63 KILX 171720
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1220 PM CDT FRI MAY 17 2013

.DISCUSSION...
ISSUED 958 AM CDT FRI MAY 17 2013

CLOUD COVER LIFTING NORTHWARD IN RESPONSE TO WEAKENING UPPER LOW
OVER SOUTHEAST MISSOURI. HAVE BEEN SEEING A FEW SPRINKLES EDGING
INTO THE FAR SOUTHEAST CWA WITH THE ALTOCUMULUS DECK. MAIN
QUESTION WILL BE WITH TIMING OF THE CONVECTION TODAY. VISIBLE
SATELLITE IMAGERY SHOWING SOME CELLULAR DEVELOPMENT IN AREAS WEST
OF FLORA AND OVER THE LOWER ILLINOIS RIVER VALLEY...WHERE LITTLE
IS LEFT OF THE CAP. MODEL GUIDANCE IS STRUGGLING WITH THE
INITIALIZATION LOCATION...BUT THE HIGHER RESOLUTION MODELS SEEM TO
BE FAVORING THE NORTHEAST HALF OF THE CWA EARLY THIS AFTERNOON AND
THE SOUTHEAST BY MID AFTERNOON. SURFACE OBS ARE NOT SHOWING ANY
OBVIOUS BOUNDARIES YET THAT COULD SERVE AS A SPECIFIC FOCUS. AS A
RESULT... HAVE NOT DONE MUCH WITH THE LOCATION OF THE HIGHEST POPS
EXCEPT FOR REFINING THE MORE LIKELY TIMES FOR THE HIGHEST VALUES.

UPDATED GRIDS HAVE BEEN SENT...BUT THE WORDED FORECASTS STILL LOOK
GOOD AT THIS TIME.

GEELHART


&&

.AVIATION...
ISSUED 1220 PM CDT FRI MAY 17 2013

SCATTERED CONVECTION HAS BEEN INCREASING OVER THE LAST COUPLE
HOURS AND WAS MOVING NORTHWARD. POP-UP NATURE AGAIN PRECLUDES
MENTION OF MORE THAN VCTS UNLESS THE STORMS BECOME MORE
ORGANIZED...AT WHICH POINT TAF AMENDMENTS WILL BE USED TO TIME ANY
PREVAILING TSRA MENTIONS. STORMS SHOULD FADE AWAY WITH SUNSET.
OVERNIGHT CONCERN WILL BE WITH MVFR/IFR POTENTIAL. SREF
PROBABILITIES FAVOR THESE CONDITIONS ADVECTING NORTHWARD OUT OF
SOUTHERN ILLINOIS AFTER 06Z AS WINDS WILL BE LIGHTER DOWN THERE...
BUT PLACEMENT OF ANY HEAVIER RAIN TODAY WILL ALSO PLAY A ROLE.
HAVE MADE LITTLE CHANGES FROM PREVIOUS TAF SET FOR NOW IN THIS
REGARD.

GEELHART

&&

.PREV DISCUSSION...
ISSUED 317 AM CDT FRI MAY 17 2013

SHORT TERM...TODAY THROUGH SUNDAY

SURFACE BOUNDARY WHICH HAS BROUGHT SCATTERED STORMS TO THE AREA THE
PAST COUPLE DAYS HAS MIGRATED BACK NORTH AND NOW LIES NEAR THE
NORTHERN FRINGE OF THE CWA. THIS FEATURE WILL SLOWLY EDGE NORTH
TODAY...AND SOUTHEAST FLOW WILL CONTINUE TO BRING IN SEASONABLE
WARMTH AND MODEST HUMIDITY WITH DEWPOINTS IN THE LOW 60S. A CLOSED
UPPER LOW NOW TRACKING INTO SOUTHEAST MO IS FORECAST TO OPEN UP
AND LIFT TOWARDS THE LOWER OHIO VALLEY BY 00Z/SAT. INCREASING
MOISTURE AND LIFT ASSOCIATED WITH THIS LOW WILL BRING SCATTERED
CONVECTION BACK TO THE AREA TODAY. FEEL HIGHEST COVERAGE WILL BE
TIED TO DIURNAL HEATING...AND FOCUSED LIKELY POPS DURING THE
AFTERNOON. FOLLOWED 4KM WRF FOR CONVECTIVE TRENDS AS THIS MODEL
HANDLED YESTERDAYS SITUATION WELL. IN AREAS THAT DO SEE RAIN...HEAVY
RAINFALL RATES WILL AGAIN BE POSSIBLE AS PW RISES TO 1.5 INCHES
AND WINDS ALOFT ARE UNDER 15 KTS. THIS ACTIVITY SHOULD QUICKLY DIE
OFF THIS EVENING AS THE ATMOSPHERE STABILIZES.

FOR SATURDAY...THE UPPER LOW WILL SLOWLY DRIFT UP THE OHIO VALLEY
WITH ENOUGH LIFT AND MOISTURE LINGERING BACK INTO EASTERN IL TO
KEEP A CHANCE OF SCATTERED STORMS GOING. FARTHER WEST...DRY
WEATHER IS EXPECTED AS BRIEF UPPER RIDGING BUILDS TOWARDS THE
MISSISSIPPI VALLEY BY 00Z/SUN. BY SATURDAY NIGHT...A DEEP UPPER
TROUGH DIGGING EAST OF THE ROCKIES SPINS UP A SURFACE LOW OVER THE
CENTRAL PLAINS. THIS SENDS A WARM FRONT NORTHEAST ACROSS MO...WITH
ELEVATED CONVECTION POSSIBLY GETTING AS FAR NORTHEAST AS THE
WESTERN CWA LATE AND HAVE ADDED SCHC POPS TO ACCOUNT FOR THIS.

00Z MODELS SHOW THE WARM FRONT LIFTING WELL NORTH OF THE AREA ON SUNDAY
AND WITH 850 MB TEMPS RISING TO NEAR +20C HIGHS IN THE MID OR
UPPER 80S ARE POSSIBLE. MUCH OF THE CWA SHOULD REMAIN DRY WITH
WEAK CAPPING IN PLACE. HOWEVER ACROSS THE WEST WILL CARRY A LOW
CHANCE FOR AFTERNOON TSTMS AS CINH IS NEGLIGIBLE AND LEAD SHORTWAVE
ENERGY LIFTING OUT OF THE WESTERN TROF COULD SPARK SOME ACTIVITY.

LONG TERM...MONDAY THROUGH THURSDAY

MUCH OF THE EXTENDED FORECAST WILL BE ACTIVE AS A HIGH AMPLITUDE SLOW
MOVING UPPER TROF SHIFTS FROM THE NORTHERN PLAINS INTO THE GREAT
LAKES BY MID-WEEK. THIS WILL REQUIRE A PROLONGED PERIOD OF CHANCE
TO LIKELY POPS INTO WEDNESDAY. SUSTAINED SOUTHERLY FLOW AHEAD OF
THE PLAINS SURFACE LOW BRINGS GULF MOISTURE AND ASSOCIATED UPPER
60S TO AROUND 70F DEW POINT POOL INTO THE MIDWEST. MODERATE TO HIGH
INSTABILITY WILL BE IN PLACE FOR MONDAY AND TUESDAY...AND AS
SEVERAL SHORTWAVES LIFT ACROSS THE CWA IN DIFLUENT SOUTHWEST
FLOW...ROUNDS OF STRONG TO SEVERE CONVECTION ARE POSSIBLE. LATEST
00Z MEDIUM RANGE MODEL RUNS SHOW THE ACTUAL COLD FRONT NOT
ARRIVING UNTIL LATE TUESDAY OR EARLY WEDNESDAY. SO IN ADDITION TO
POSSIBLE SEVERE WEATHER HEAVY RAIN ALSO MAY BE REALIZED IF THE CURRENTLY
ADVERTISED TRENDS OF A STRONG SLOW MOVING SYNOPTIC SYSTEM AND HIGH
PW AIRMASS MATERIALIZE. TEMPERATURES WILL REMAIN SEVERAL DEGREES
ABOVE NORMAL UNTIL THE FRONT EVENTUALLY PASSES. POST-FRONTAL
AIRMASS WILL BRING TEMPS BACK TO NEAR OR SLIGHTLY BELOW NORMAL FOR
THE END OF NEXT WEEK.

25


&&

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

$$

000
FXUS63 KILX 171458
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
958 AM CDT FRI MAY 17 2013

.DISCUSSION...
ISSUED 958 AM CDT FRI MAY 17 2013

CLOUD COVER LIFTING NORTHWARD IN RESPONSE TO WEAKENING UPPER LOW
OVER SOUTHEAST MISSOURI. HAVE BEEN SEEING A FEW SPRINKLES EDGING
INTO THE FAR SOUTHEAST CWA WITH THE ALTOCUMULUS DECK. MAIN
QUESTION WILL BE WITH TIMING OF THE CONVECTION TODAY. VISIBLE
SATELLITE IMAGERY SHOWING SOME CELLULAR DEVELOPMENT IN AREAS WEST
OF FLORA AND OVER THE LOWER ILLINOIS RIVER VALLEY...WHERE LITTLE
IS LEFT OF THE CAP. MODEL GUIDANCE IS STRUGGLING WITH THE
INITIALIZATION LOCATION...BUT THE HIGHER RESOLUTION MODELS SEEM TO
BE FAVORING THE NORTHEAST HALF OF THE CWA EARLY THIS AFTERNOON AND
THE SOUTHEAST BY MID AFTERNOON. SURFACE OBS ARE NOT SHOWING ANY
OBVIOUS BOUNDARIES YET THAT COULD SERVE AS A SPECIFIC FOCUS. AS A
RESULT... HAVE NOT DONE MUCH WITH THE LOCATION OF THE HIGHEST POPS
EXCEPT FOR REFINING THE MORE LIKELY TIMES FOR THE HIGHEST VALUES.

UPDATED GRIDS HAVE BEEN SENT...BUT THE WORDED FORECASTS STILL LOOK
GOOD AT THIS TIME.

GEELHART

&&

.AVIATION...
ISSUED 622 AM CDT FRI MAY 17 2013

CONDITIONS AT ALL TAF SITES WILL BE VFR MOST OF THE PERIOD WITH
VCTS AT ALL SITES FROM LATER THIS MORNING UNTIL EARLY THIS
EVENING. CONVECTION WILL BE VERY DIURNAL SO IT SHOULD DIMINISH AND
END VERY QUICKLY. ONCE THE PRECIP ENDS AM EXPECTING FOG TO DEVELOP
AT ALL SITES TONIGHT AND CONTINUE UNTIL TOMORROW MORNING. FOG
SHOULD BRING CONDITIONS DOWN TO MVFR IN THE EVENING AND THEN IFR
AT ALL SITES AFTER MIDNIGHT. WINDS WILL BE SOUTHEAST AROUND 10KTS
TODAY AND THEN BECOME LIGHT AND VARIABLE REMAINDER OF THE TAF
PERIOD.

AUTEN
&&

.PREV DISCUSSION...
ISSUED 317 AM CDT FRI MAY 17 2013

SHORT TERM...TODAY THROUGH SUNDAY

SURFACE BOUNDARY WHICH HAS BROUGHT SCATTERED STORMS TO THE AREA THE
PAST COUPLE DAYS HAS MIGRATED BACK NORTH AND NOW LIES NEAR THE
NORTHERN FRINGE OF THE CWA. THIS FEATURE WILL SLOWLY EDGE NORTH
TODAY...AND SOUTHEAST FLOW WILL CONTINUE TO BRING IN SEASONABLE
WARMTH AND MODEST HUMIDITY WITH DEWPOINTS IN THE LOW 60S. A CLOSED
UPPER LOW NOW TRACKING INTO SOUTHEAST MO IS FORECAST TO OPEN UP
AND LIFT TOWARDS THE LOWER OHIO VALLEY BY 00Z/SAT. INCREASING
MOISTURE AND LIFT ASSOCIATED WITH THIS LOW WILL BRING SCATTERED
CONVECTION BACK TO THE AREA TODAY. FEEL HIGHEST COVERAGE WILL BE
TIED TO DIURNAL HEATING...AND FOCUSED LIKELY POPS DURING THE
AFTERNOON. FOLLOWED 4KM WRF FOR CONVECTIVE TRENDS AS THIS MODEL
HANDLED YESTERDAYS SITUATION WELL. IN AREAS THAT DO SEE RAIN...HEAVY
RAINFALL RATES WILL AGAIN BE POSSIBLE AS PW RISES TO 1.5 INCHES
AND WINDS ALOFT ARE UNDER 15 KTS. THIS ACTIVITY SHOULD QUICKLY DIE
OFF THIS EVENING AS THE ATMOSPHERE STABILIZES.

FOR SATURDAY...THE UPPER LOW WILL SLOWLY DRIFT UP THE OHIO VALLEY
WITH ENOUGH LIFT AND MOISTURE LINGERING BACK INTO EASTERN IL TO
KEEP A CHANCE OF SCATTERED STORMS GOING. FARTHER WEST...DRY
WEATHER IS EXPECTED AS BRIEF UPPER RIDGING BUILDS TOWARDS THE
MISSISSIPPI VALLEY BY 00Z/SUN. BY SATURDAY NIGHT...A DEEP UPPER
TROUGH DIGGING EAST OF THE ROCKIES SPINS UP A SURFACE LOW OVER THE
CENTRAL PLAINS. THIS SENDS A WARM FRONT NORTHEAST ACROSS MO...WITH
ELEVATED CONVECTION POSSIBLY GETTING AS FAR NORTHEAST AS THE
WESTERN CWA LATE AND HAVE ADDED SCHC POPS TO ACCOUNT FOR THIS.

00Z MODELS SHOW THE WARM FRONT LIFTING WELL NORTH OF THE AREA ON SUNDAY
AND WITH 850 MB TEMPS RISING TO NEAR +20C HIGHS IN THE MID OR
UPPER 80S ARE POSSIBLE. MUCH OF THE CWA SHOULD REMAIN DRY WITH
WEAK CAPPING IN PLACE. HOWEVER ACROSS THE WEST WILL CARRY A LOW
CHANCE FOR AFTERNOON TSTMS AS CINH IS NEGLIGIBLE AND LEAD SHORTWAVE
ENERGY LIFTING OUT OF THE WESTERN TROF COULD SPARK SOME ACTIVITY.

LONG TERM...MONDAY THROUGH THURSDAY

MUCH OF THE EXTENDED FORECAST WILL BE ACTIVE AS A HIGH AMPLITUDE SLOW
MOVING UPPER TROF SHIFTS FROM THE NORTHERN PLAINS INTO THE GREAT
LAKES BY MID-WEEK. THIS WILL REQUIRE A PROLONGED PERIOD OF CHANCE
TO LIKELY POPS INTO WEDNESDAY. SUSTAINED SOUTHERLY FLOW AHEAD OF
THE PLAINS SURFACE LOW BRINGS GULF MOISTURE AND ASSOCIATED UPPER
60S TO AROUND 70F DEW POINT POOL INTO THE MIDWEST. MODERATE TO HIGH
INSTABILITY WILL BE IN PLACE FOR MONDAY AND TUESDAY...AND AS
SEVERAL SHORTWAVES LIFT ACROSS THE CWA IN DIFLUENT SOUTHWEST
FLOW...ROUNDS OF STRONG TO SEVERE CONVECTION ARE POSSIBLE. LATEST
00Z MEDIUM RANGE MODEL RUNS SHOW THE ACTUAL COLD FRONT NOT
ARRIVING UNTIL LATE TUESDAY OR EARLY WEDNESDAY. SO IN ADDITION TO
POSSIBLE SEVERE WEATHER HEAVY RAIN ALSO MAY BE REALIZED IF THE CURRENTLY
ADVERTISED TRENDS OF A STRONG SLOW MOVING SYNOPTIC SYSTEM AND HIGH
PW AIRMASS MATERIALIZE. TEMPERATURES WILL REMAIN SEVERAL DEGREES
ABOVE NORMAL UNTIL THE FRONT EVENTUALLY PASSES. POST- FRONTAL
AIRMASS WILL BRING TEMPS BACK TO NEAR OR SLIGHTLY BELOW NORMAL FOR
THE END OF NEXT WEEK.

25

&&

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

$$

000
FXUS63 KILX 171122
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
622 AM CDT FRI MAY 17 2013

.DISCUSSION...
ISSUED 317 AM CDT FRI MAY 17 2013

SHORT TERM...TODAY THROUGH SUNDAY

SURFACE BOUNDARY WHICH HAS BROUGHT SCATTERED STORMS TO THE AREA THE
PAST COUPLE DAYS HAS MIGRATED BACK NORTH AND NOW LIES NEAR THE
NORTHERN FRINGE OF THE CWA. THIS FEATURE WILL SLOWLY EDGE NORTH
TODAY...AND SOUTHEAST FLOW WILL CONTINUE TO BRING IN SEASONABLE
WARMTH AND MODEST HUMIDITY WITH DEWPOINTS IN THE LOW 60S. A CLOSED
UPPER LOW NOW TRACKING INTO SOUTHEAST MO IS FORECAST TO OPEN UP
AND LIFT TOWARDS THE LOWER OHIO VALLEY BY 00Z/SAT. INCREASING
MOISTURE AND LIFT ASSOCIATED WITH THIS LOW WILL BRING SCATTERED
CONVECTION BACK TO THE AREA TODAY. FEEL HIGHEST COVERAGE WILL BE
TIED TO DIURNAL HEATING...AND FOCUSED LIKELY POPS DURING THE
AFTERNOON. FOLLOWED 4KM WRF FOR CONVECTIVE TRENDS AS THIS MODEL
HANDLED YESTERDAYS SITUATION WELL. IN AREAS THAT DO SEE RAIN...HEAVY
RAINFALL RATES WILL AGAIN BE POSSIBLE AS PW RISES TO 1.5 INCHES
AND WINDS ALOFT ARE UNDER 15 KTS. THIS ACTIVITY SHOULD QUICKLY DIE
OFF THIS EVENING AS THE ATMOSPHERE STABILIZES.

FOR SATURDAY...THE UPPER LOW WILL SLOWLY DRIFT UP THE OHIO VALLEY
WITH ENOUGH LIFT AND MOISTURE LINGERING BACK INTO EASTERN IL TO
KEEP A CHANCE OF SCATTERED STORMS GOING. FARTHER WEST...DRY
WEATHER IS EXPECTED AS BRIEF UPPER RIDGING BUILDS TOWARDS THE
MISSISSIPPI VALLEY BY 00Z/SUN. BY SATURDAY NIGHT...A DEEP UPPER
TROUGH DIGGING EAST OF THE ROCKIES SPINS UP A SURFACE LOW OVER THE
CENTRAL PLAINS. THIS SENDS A WARM FRONT NORTHEAST ACROSS MO...WITH
ELEVATED CONVECTION POSSIBLY GETTING AS FAR NORTHEAST AS THE
WESTERN CWA LATE AND HAVE ADDED SCHC POPS TO ACCOUNT FOR THIS.

00Z MODELS SHOW THE WARM FRONT LIFTING WELL NORTH OF THE AREA ON SUNDAY
AND WITH 850 MB TEMPS RISING TO NEAR +20C HIGHS IN THE MID OR
UPPER 80S ARE POSSIBLE. MUCH OF THE CWA SHOULD REMAIN DRY WITH
WEAK CAPPING IN PLACE. HOWEVER ACROSS THE WEST WILL CARRY A LOW
CHANCE FOR AFTERNOON TSTMS AS CINH IS NEGLIGIBLE AND LEAD SHORTWAVE
ENERGY LIFTING OUT OF THE WESTERN TROF COULD SPARK SOME ACTIVITY.

LONG TERM...MONDAY THROUGH THURSDAY

MUCH OF THE EXTENDED FORECAST WILL BE ACTIVE AS A HIGH AMPLITUDE SLOW
MOVING UPPER TROF SHIFTS FROM THE NORTHERN PLAINS INTO THE GREAT
LAKES BY MID-WEEK. THIS WILL REQUIRE A PROLONGED PERIOD OF CHANCE
TO LIKELY POPS INTO WEDNESDAY. SUSTAINED SOUTHERLY FLOW AHEAD OF
THE PLAINS SURFACE LOW BRINGS GULF MOISTURE AND ASSOCIATED UPPER
60S TO AROUND 70F DEWPOINT POOL INTO THE MIDWEST. MODERATE TO HIGH
INSTABILITY WILL BE IN PLACE FOR MONDAY AND TUESDAY...AND AS
SEVERAL SHORTWAVES LIFT ACROSS THE CWA IN DIFLUENT SOUTHWEST
FLOW...ROUNDS OF STRONG TO SEVERE CONVECTION ARE POSSIBLE. LATEST
00Z MEDIUM RANGE MODEL RUNS SHOW THE ACTUAL COLD FRONT NOT
ARRIVING UNTIL LATE TUESDAY OR EARLY WEDNESDAY. SO IN ADDITION TO
POSSIBLE SEVERE WEATHER HEAVY RAIN ALSO MAY BE REALIZED IF THE CURRENTLY
ADVERTISED TRENDS OF A STRONG SLOW MOVING SYNOPTIC SYSTEM AND HIGH
PW AIRMASS MATERIALIZE. TEMPERATURES WILL REMAIN SEVERAL DEGREES
ABOVE NORMAL UNTIL THE FRONT EVENTUALLY PASSES. POST- FRONTAL
AIRMASS WILL BRING TEMPS BACK TO NEAR OR SLIGHTLY BELOW NORMAL FOR
THE END OF NEXT WEEK.

25
&&

.AVIATION...
ISSUED 622 AM CDT FRI MAY 17 2013

CONDITIONS AT ALL TAF SITES WILL BE VFR MOST OF THE PERIOD WITH
VCTS AT ALL SITES FROM LATER THIS MORNING UNTIL EARLY THIS
EVENING. CONVECTION WILL BE VERY DIURNAL SO IT SHOULD DIMINISH AND
END VERY QUICKLY. ONCE THE PRECIP ENDS AM EXPECTING FOG TO DEVELOP
AT ALL SITES TONIGHT AND CONTINUE UNTIL TOMORROW MORNING. FOG
SHOULD BRING CONDITIONS DOWN TO MVFR IN THE EVENING AND THEN IFR
AT ALL SITES AFTER MIDNIGHT. WINDS WILL BE SOUTHEAST AROUND 10KTS
TODAY AND THEN BECOME LIGHT AND VARIABLE REMAINDER OF THE TAF
PERIOD.

AUTEN
&&

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

$$

000
FXUS63 KILX 170817
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
317 AM CDT FRI MAY 17 2013

.DISCUSSION...
ISSUED 317 AM CDT FRI MAY 17 2013

SHORT TERM...TODAY THROUGH SUNDAY

SURFACE BOUNDARY WHICH HAS BROUGHT SCATTERED STORMS TO THE AREA THE
PAST COUPLE DAYS HAS MIGRATED BACK NORTH AND NOW LIES NEAR THE
NORTHERN FRINGE OF THE CWA. THIS FEATURE WILL SLOWLY EDGE NORTH
TODAY...AND SOUTHEAST FLOW WILL CONTINUE TO BRING IN SEASONABLE
WARMTH AND MODEST HUMIDITY WITH DEWPOINTS IN THE LOW 60S. A CLOSED
UPPER LOW NOW TRACKING INTO SOUTHEAST MO IS FORECAST TO OPEN UP
AND LIFT TOWARDS THE LOWER OHIO VALLEY BY 00Z/SAT. INCREASING
MOISTURE AND LIFT ASSOCIATED WITH THIS LOW WILL BRING SCATTERED
CONVECTION BACK TO THE AREA TODAY. FEEL HIGHEST COVERAGE WILL BE
TIED TO DIURNAL HEATING...AND FOCUSED LIKELY POPS DURING THE
AFTERNOON. FOLLOWED 4KM WRF FOR CONVECTIVE TRENDS AS THIS MODEL
HANDLED YESTERDAYS SITUATION WELL. IN AREAS THAT DO SEE RAIN...HEAVY
RAINFALL RATES WILL AGAIN BE POSSIBLE AS PW RISES TO 1.5 INCHES
AND WINDS ALOFT ARE UNDER 15 KTS. THIS ACTIVITY SHOULD QUICKLY DIE
OFF THIS EVENING AS THE ATMOSPHERE STABILIZES.

FOR SATURDAY...THE UPPER LOW WILL SLOWLY DRIFT UP THE OHIO VALLEY
WITH ENOUGH LIFT AND MOISTURE LINGERING BACK INTO EASTERN IL TO
KEEP A CHANCE OF SCATTERED STORMS GOING. FARTHER WEST...DRY
WEATHER IS EXPECTED AS BRIEF UPPER RIDGING BUILDS TOWARDS THE
MISSISSIPPI VALLEY BY 00Z/SUN. BY SATURDAY NIGHT...A DEEP UPPER
TROUGH DIGGING EAST OF THE ROCKIES SPINS UP A SURFACE LOW OVER THE
CENTRAL PLAINS. THIS SENDS A WARM FRONT NORTHEAST ACROSS MO...WITH
ELEVATED CONVECTION POSSIBLY GETTING AS FAR NORTHEAST AS THE
WESTERN CWA LATE AND HAVE ADDED SCHC POPS TO ACCOUNT FOR THIS.

00Z MODELS SHOW THE WARM FRONT LIFTING WELL NORTH OF THE AREA ON SUNDAY
AND WITH 850 MB TEMPS RISING TO NEAR +20C HIGHS IN THE MID OR
UPPER 80S ARE POSSIBLE. MUCH OF THE CWA SHOULD REMAIN DRY WITH
WEAK CAPPING IN PLACE. HOWEVER ACROSS THE WEST WILL CARRY A LOW
CHANCE FOR AFTERNOON TSTMS AS CINH IS NEGLIGIBLE AND LEAD SHORTWAVE
ENERGY LIFTING OUT OF THE WESTERN TROF COULD SPARK SOME ACTIVITY.

LONG TERM...MONDAY THROUGH THURSDAY

MUCH OF THE EXTENDED FORECAST WILL BE ACTIVE AS A HIGH AMPLITUDE SLOW
MOVING UPPER TROF SHIFTS FROM THE NORTHERN PLAINS INTO THE GREAT
LAKES BY MID-WEEK. THIS WILL REQUIRE A PROLONGED PERIOD OF CHANCE
TO LIKELY POPS INTO WEDNESDAY. SUSTAINED SOUTHERLY FLOW AHEAD OF
THE PLAINS SURFACE LOW BRINGS GULF MOISTURE AND ASSOCIATED UPPER
60S TO AROUND 70F DEWPOINT POOL INTO THE MIDWEST. MODERATE TO HIGH
INSTABILITY WILL BE IN PLACE FOR MONDAY AND TUESDAY...AND AS
SEVERAL SHORTWAVES LIFT ACROSS THE CWA IN DIFLUENT SOUTHWEST
FLOW...ROUNDS OF STRONG TO SEVERE CONVECTION ARE POSSIBLE. LATEST
00Z MEDIUM RANGE MODEL RUNS SHOW THE ACTUAL COLD FRONT NOT
ARRIVING UNTIL LATE TUESDAY OR EARLY WEDNESDAY. SO IN ADDITION TO
POSSIBLE SEVERE WEATHER HEAVY RAIN ALSO MAY BE REALIZED IF THE CURRENTLY
ADVERTISED TRENDS OF A STRONG SLOW MOVING SYNOPTIC SYSTEM AND HIGH
PW AIRMASS MATERIALIZE. TEMPERATURES WILL REMAIN SEVERAL DEGREES
ABOVE NORMAL UNTIL THE FRONT EVENTUALLY PASSES. POST- FRONTAL
AIRMASS WILL BRING TEMPS BACK TO NEAR OR SLIGHTLY BELOW NORMAL FOR
THE END OF NEXT WEEK.



25
&&

.AVIATION...
ISSUED 1154 PM CDT THU MAY 16 2013

04Z/11PM RADAR IMAGERY SHOWS DRY CONDITIONS ACROSS MUCH OF CENTRAL
ILLINOIS...WITH ONE CLUSTER OF PERSISTENT SHOWERS/THUNDER BETWEEN
KVYS AND KPNT. STATIONARY FRONTAL BOUNDARY JUST NORTH OF THE I-74
CORRIDOR WILL CONTINUE TO TRIGGER ISOLATED CONVECTION
OVERNIGHT...HOWEVER IT IS EXPECTED TO REMAIN NORTH OF THE KILX
TERMINALS. UPPER LOW CURRENTLY SPINNING OVER THE OZARKS WILL LIFT
NORTHEASTWARD INTO THE OHIO RIVER VALLEY ON FRIDAY. DEEPER
MOISTURE ARRIVING WITH THIS FEATURE WILL LEAD TO SCATTERED SHOWERS
AND THUNDERSTORMS THROUGHOUT THE DAY INTO THE EARLY EVENING. BASED
ON NAM TIMING...HAVE INTRODUCED VCTS AT KSPI AND KDEC BY
13Z...THEN FURTHER NORTH TO KPIA BY 16Z. AS LOW SHIFTS FURTHER
EAST AND DAYTIME INSTABILITY IS LOST...CONVECTION WILL DISSIPATE
AFTER 02Z. WINDS WILL BE LIGHT AND SOUTHERLY OVERNIGHT...THEN WILL
BACK TO E/SE ON FRIDAY.

BARNES
&&

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

$$

000
FXUS63 KILX 170454
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1154 PM CDT THU MAY 16 2013

.DISCUSSION...
ISSUED 743 PM CDT THU MAY 16 2013

SYNOPTIC FRONTAL BOUNDARY HAS LIFTED NORTHWARD TO NEAR THE I-74
CORRIDOR EARLY THIS EVENING. DEWPOINTS TO THE SOUTH OF THE
BOUNDARY ARE IN THE UPPER 50S AND LOWER 60S ACROSS MUCH OF THE
KILX CWA...WHILE DEWPOINTS NORTH OF THE FRONT ARE ONLY IN THE 40S
ACROSS NORTHERN ILLINOIS. MESOSCALE OUTFLOW BOUNDARY FROM CONVECTION
EARLIER TODAY FROM NEAR SPRINGFIELD S/SE TO LAWRENCEVILLE HAS
LIFTED NORTHWARD AS WELL...RESULTING IN A RELATIVELY STABLE
AIRMASS ACROSS THE AREA. BEST INSTABILITY AND LIFT IS CURRENTLY
FOCUSED ALONG/NORTH OF THE FRONTAL BOUNDARY ACROSS THE FAR
NORTHERN CWA. A FEW SHOWERS HAVE DEVELOPED ACROSS WOODFORD AND
NORTHERN MCLEAN COUNTIES OVER THE PAST HOUR...AND THIS AREA WILL
HAVE TO BE MONITORED FOR ADDITIONAL DEVELOPMENT AS THE EVENING
PROGRESSES. WILL MAINTAIN SLIGHT CHANCE POPS EVERYWHERE DURING THE
EVENING...THEN WILL LIMIT POPS TO ONLY THE NORTHERN CWA IN CLOSER
PROXIMITY TO THE FRONT OVERNIGHT. ZONE UPDATE HAS ALREADY BEEN
SENT.



&&

.AVIATION...
ISSUED 1154 PM CDT THU MAY 16 2013

04Z/11PM RADAR IMAGERY SHOWS DRY CONDITIONS ACROSS MUCH OF CENTRAL
ILLINOIS...WITH ONE CLUSTER OF PERSISTENT SHOWERS/THUNDER BETWEEN
KVYS AND KPNT. STATIONARY FRONTAL BOUNDARY JUST NORTH OF THE I-74
CORRIDOR WILL CONTINUE TO TRIGGER ISOLATED CONVECTION
OVERNIGHT...HOWEVER IT IS EXPECTED TO REMAIN NORTH OF THE KILX
TERMINALS. UPPER LOW CURRENTLY SPINNING OVER THE OZARKS WILL LIFT
NORTHEASTWARD INTO THE OHIO RIVER VALLEY ON FRIDAY. DEEPER
MOISTURE ARRIVING WITH THIS FEATURE WILL LEAD TO SCATTERED SHOWERS
AND THUNDERSTORMS THROUGHOUT THE DAY INTO THE EARLY EVENING. BASED
ON NAM TIMING...HAVE INTRODUCED VCTS AT KSPI AND KDEC BY
13Z...THEN FURTHER NORTH TO KPIA BY 16Z. AS LOW SHIFTS FURTHER
EAST AND DAYTIME INSTABILITY IS LOST...CONVECTION WILL DISSIPATE
AFTER 02Z. WINDS WILL BE LIGHT AND SOUTHERLY OVERNIGHT...THEN WILL
BACK TO E/SE ON FRIDAY.

BARNES
&&

.PREV DISCUSSION...
ISSUED 300 PM CDT THU MAY 16 2013

A STATIONARY FRONT WILL OSCILLATE NORTH AND SOUTH ACROSS ILLINOIS
OVER THE NEXT DAY AND A HALF...THEN THE FRONT SHOULD LIFT NORTH AS
A WARM FRONT FOR THE WEEKEND...PUSHING HIGHS INTO THE MID TO UPPER
80S BY SUNDAY. BANDS OF THUNDERSTORMS THAT DEVELOP THROUGH
TOMORROW WILL LIKELY BE SLOW MOVING, HEAVY RAIN PRODUCERS LIKE
TODAY`S STORMS. LOCALIZED AREAS COULD SEE SIGNIFICANT RAINFALL OF
2-3 INCHES IN A COUPLE HOURS WHILE NEARBY AREAS SEE LITTLE RAIN.
PINPOINTING THAT ACTIVITY WILL BE DIFFICULT...BUT DIURNAL TRENDS
SHOULD PUT MOST OF THE CONVECTION DURING THE AFTERNOON
TOMORROW...ESPECIALLY NEAR ANY OUTFLOW BOUNDARIES SET DOWN BY
TODAY`S STORMS.

A SLIGHT LULL IN STORMS SHOULD OCCUR THIS WEEKEND AS RIDGING IN
THE PLAINS BUILDS INTO IL. A STRONGER COLD FRONT IS EXPECTED TO
PUSH ACROSS IL ON MONDAY AND MONDAY NIGHT...BRINGING OUR BETTER
CHANCES OF THUNDERSTORMS. WE ARE IN THE SPC DAY 5 OUTLOOK FOR
STRONG TO SEVERE STORMS MON-MON NIGHT. A COOL DOWN IS PROJECTED
FOR TUES THROUGH THURSDAY BEHIND THE COLD FRONT...PULLING HIGHS
BACK INTO THE 70S...BUT STILL AT OR ABOVE NORMAL.

SHORT TERM...TONIGHT THROUGH SUNDAY.

SHOWERS AND STORMS WILL GENERALLY BE DIMINISHING AS WE HEAD INTO
THE EVENING. THE LINE OF CONVECTION MAINLY CENTERED ON A LINE
FROM RUSHVILLE TO TAYLORVILLE TO EFFINGHAM TO LAWRENCEVILLE...IS
EXPECTED TO LIFT NORTH THIS EVENING. THE RAP MODEL IS SHOWING THE
INSTABILITY AXIS FOLLOWING THE SAME PROGRESSION...WITH SOME SHOWER
ACTIVITY DEVELOPING DURING THAT TIME. IN THE LAST HOUR...PRECIP
COVERAGE AND UPDRAFT INTENSITY HAVE ALREADY BEGUN DIMINISHING OR
WEAKENING RESPECTIVELY. RADAR LOOPS SHOW VARIOUS OUTFLOW
BOUNDARIES MOVING NORTH ACROSS OUR COUNTIES...AND MAY END UP BEING
A FOCUS FOR EVENING SHOWERS ALONG AND NORTH OF I-72.
STILL...COVERAGE WILL BE ISOLATED IN GENERAL.

FRIDAY MORNING...THE LOCATION OF THE BEST INSTABILITY WILL BE
ALONG AND NORTH OF I-74...SO ANY MORNING CONVECTION ON FRIDAY MAY
BE FOCUSED IN THAT AREA. DURING THE AFTERNOON...AN UPPER LOW
PRESSURE WAVE IS FORECAST TO LIFT NORTHEAST ACROSS IL...IN CONCERT
WITH INCREASING MOISTURE AND INSTABILITY AS THE STATIONARY FRONT
OSCILLATES NORTHWARD WITH THE WAVE. COVERAGE OF STORMS SHOULD BE
MORE THAN TODAY...BASED ON THE SUPPORT OF THE UPPER WAVE AND JET
DYNAMICS. ANY SUNSHINE THAT HEATS UP THE BOUNDARY LAYER WILL HELP
TO CREATE A FEW STRONG UPDRAFTS WITH SMALL HAIL, GUSTY WINDS, AND
VERY HEAVY RAINFALL.

THE STORMS MAY LINGER INTO THE EVENING EAST OF I-57...BUT SHOULD
DIMINISH BY MIDNIGHT. BY 12Z SAT MORNING...THE UPPER LOW IS
FORECAST TO BE CENTERED IN SOUTHERN INDIANA...WHICH WILL HELP PUT
PRECIP CHANCES MAINLY IN OUR SOUTHEAST COUNTIES ALONG AND SOUTHEAST
OF A LINE FROM SHELBYVILLE TO PARIS. THE SLOW DEPARTURE OF THE LOW
WILL KEEP CHANCES OF SHOWERS AND STORMS THROUGH SATURDAY AFTERNOON
IN THE SOUTHEAST.

THE WARM FRONT DEPARTING INTO NORTHERN IL FOLLOWED BY RIDGING AT
THE SURFACE AND ALOFT SATURDAY NIGHT AND SUNDAY SHOULD HELP MAKE
MOST AREAS DRY FOR THE LAST HALF OF THE WEEKEND. THE ADDITIONAL
SUNSHINE ON SUNDAY ALONG WITH DEEPER WARM AIR WILL HELP PUSH HIGH
TEMPS INTO THE MID TO UPPER 80S...WITH MUGGY DEWPOINTS IN THE
UPPER 60S TO NEAR 70. HEAT INDEX READINGS SUNDAY AFTERNOON WILL
CLIMB INTO THE 90S.

LONG TERM...MONDAY THROUGH THURSDAY.

ON MONDAY...AN OCCLUDING LOW PRESSURE PRESSURE SYSTEM IN THE
EASTERN DAKOTAS WILL CREATE SOME WARM FRONTOGENESIS TO THE
SOUTHEAST OF THE LOW ACROSS OUR NORTHERN COUNTIES. THAT WILL
CREATE A FOCUS FOR CONVECTION BY MONDAY AFTERNOON. MONDAY
NIGHT...A COLD FRONT WILL MOVE ACROSS IL PRODUCING STRONG TO
SEVERE STORMS AS ML-CAPE VALUES CLIMB TO NEAR 2K J/KG. BULK SHEAR
IS EXPECTED TO REACH OVER 40KT AS WELL...SO EMBEDDED SUPERCELLS
WILL BE POSSIBLE IN THE LINE OF STORMS THAT MOVES THROUGH.

STORMS ARE EXPECTED TO LINGER INTO TUESDAY AS THE UPPER COLD POOL
SLOWLY MAKES PROGRESS INTO ILLINOIS. WE KEPT LIKELY POPS SOUTHEAST
OF I-72...AND CHANCE ELSEWHERE. TUESDAY NIGHT PRECIP COVERAGE
SHOULD DIMINISH...WITH CHANCE POPS STILL IN PLACE ACROSS THE
BOARD. AN ELONGATED SURFACE TROUGH IS PROJECTED TO LINGER ACROSS
NORTHERN ILLINOIS INTO WED AS THE OCCLUDED UPPER LOW BECOMES MORE
OF AN OPEN WAVE AND SEND A SURFACE LOW EASTWARD ACROSS WISCONSIN.
THAT PROGRESSION WILL KEEP SCATTERED SHOWERS POSSIBLE AS FAR
SOUTH AS CENTRAL ILLINOIS THROUGH THURSDAY...ESPECIALLY EAST OF
I-55. PRECIP AMOUNTS MID WEEK SHOULD REMAIN LIGHT...BUT STILL
CLOUDS AND COOLER AIR WILL KEEP HIGH TEMPS BACK IN THE
70S...CLOSER TO NORMAL.


&&

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

$$

000
FXUS63 KILX 170043
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
743 PM CDT THU MAY 16 2013

.DISCUSSION...
ISSUED 743 PM CDT THU MAY 16 2013

SYNOPTIC FRONTAL BOUNDARY HAS LIFTED NORTHWARD TO NEAR THE I-74
CORRIDOR EARLY THIS EVENING. DEWPOINTS TO THE SOUTH OF THE
BOUNDARY ARE IN THE UPPER 50S AND LOWER 60S ACROSS MUCH OF THE
KILX CWA...WHILE DEWPOINTS NORTH OF THE FRONT ARE ONLY IN THE 40S
ACROSS NORTHERN ILLINOIS. MESOSCALE OUTFLOW BOUNDARY FROM CONVECTION
EARLIER TODAY FROM NEAR SPRINGFIELD S/SE TO LAWRENCEVILLE HAS
LIFTED NORTHWARD AS WELL...RESULTING IN A RELATIVELY STABLE
AIRMASS ACROSS THE AREA. BEST INSTABILITY AND LIFT IS CURRENTLY
FOCUSED ALONG/NORTH OF THE FRONTAL BOUNDARY ACROSS THE FAR
NORTHERN CWA. A FEW SHOWERS HAVE DEVELOPED ACROSS WOODFORD AND
NORTHERN MCLEAN COUNTIES OVER THE PAST HOUR...AND THIS AREA WILL
HAVE TO BE MONITORED FOR ADDITIONAL DEVELOPMENT AS THE EVENING
PROGRESSES. WILL MAINTAIN SLIGHT CHANCE POPS EVERYWHERE DURING THE
EVENING...THEN WILL LIMIT POPS TO ONLY THE NORTHERN CWA IN CLOSER
PROXIMITY TO THE FRONT OVERNIGHT. ZONE UPDATE HAS ALREADY BEEN
SENT.

BARNES
&&

.AVIATION...
ISSUED 635 PM CDT THU MAY 16 2013

MAIN AVIATION FORECAST CHALLENGE WILL BE TRYING TO PINPOINT TIMING
OF POTENTIAL CONVECTION OVER THE NEXT 24 HOURS. MESOSCALE OUTFLOW
BOUNDARY FROM STORMS ACROSS SOUTH-CENTRAL/SOUTHEAST ILLINOIS
EARLIER TODAY HAS DRIFTED NORTH OF THE I-74 TERMINALS...RESULTING
IN A RATHER STABLE ENVIRONMENT ACROSS MUCH OF CENTRAL ILLINOIS
EARLY THIS EVENING. WILL HAVE TO KEEP AN EYE ON A CU-FIELD ALONG
THE DISSIPATING OUTFLOW JUST NORTH OF KPIA AND KBMI...AS 21Z HRRR
TRIES TO FIRE SCATTERED STORMS IN THIS GENERAL AREA AFTER 03Z. AT
THIS POINT...WILL LEAVE THUNDER MENTION OUT OF THE TAFS THROUGH
TONIGHT. UPPER LOW CURRENTLY SPINNING OVER THE OZARKS WILL PIVOT
NORTHEASTWARD ON FRIDAY...SPREADING DEEPER MOISTURE NORTHWARD INTO
THE AREA. WILL THEREFORE INTRODUCE VCTS AT KSPI AND KDEC AFTER
14Z...THEN FURTHER NORTH INTO KPIA BY 17Z. WINDS WILL INITIALLY BE
FROM THE S/SW...THEN WILL BACK TO SE BY MID TO LATE EVENING. WITH
LIGHT WINDS EXPECTED OVERNIGHT...FORECAST SOUNDINGS ARE SUGGESTING
THE POTENTIAL FOR FOG DEVELOPMENT. WILL REDUCE VISBYS TO BETWEEN 4
AND 5SM AFTER 07Z ACCORDINGLY.

BARNES
&&

.PREV DISCUSSION...
ISSUED 300 PM CDT THU MAY 16 2013

A STATIONARY FRONT WILL OSCILLATE NORTH AND SOUTH ACROSS ILLINOIS
OVER THE NEXT DAY AND A HALF...THEN THE FRONT SHOULD LIFT NORTH AS
A WARM FRONT FOR THE WEEKEND...PUSHING HIGHS INTO THE MID TO UPPER
80S BY SUNDAY. BANDS OF THUNDERSTORMS THAT DEVELOP THROUGH
TOMORROW WILL LIKELY BE SLOW MOVING, HEAVY RAIN PRODUCERS LIKE
TODAY`S STORMS. LOCALIZED AREAS COULD SEE SIGNIFICANT RAINFALL OF
2-3 INCHES IN A COUPLE HOURS WHILE NEARBY AREAS SEE LITTLE RAIN.
PINPOINTING THAT ACTIVITY WILL BE DIFFICULT...BUT DIURNAL TRENDS
SHOULD PUT MOST OF THE CONVECTION DURING THE AFTERNOON
TOMORROW...ESPECIALLY NEAR ANY OUTFLOW BOUNDARIES SET DOWN BY
TODAY`S STORMS.

A SLIGHT LULL IN STORMS SHOULD OCCUR THIS WEEKEND AS RIDGING IN
THE PLAINS BUILDS INTO IL. A STRONGER COLD FRONT IS EXPECTED TO
PUSH ACROSS IL ON MONDAY AND MONDAY NIGHT...BRINGING OUR BETTER
CHANCES OF THUNDERSTORMS. WE ARE IN THE SPC DAY 5 OUTLOOK FOR
STRONG TO SEVERE STORMS MON-MON NIGHT. A COOL DOWN IS PROJECTED
FOR TUES THROUGH THURSDAY BEHIND THE COLD FRONT...PULLING HIGHS
BACK INTO THE 70S...BUT STILL AT OR ABOVE NORMAL.

SHORT TERM...TONIGHT THROUGH SUNDAY.

SHOWERS AND STORMS WILL GENERALLY BE DIMINISHING AS WE HEAD INTO
THE EVENING. THE LINE OF CONVECTION MAINLY CENTERED ON A LINE
FROM RUSHVILLE TO TAYLORVILLE TO EFFINGHAM TO LAWRENCEVILLE...IS
EXPECTED TO LIFT NORTH THIS EVENING. THE RAP MODEL IS SHOWING THE
INSTABILITY AXIS FOLLOWING THE SAME PROGRESSION...WITH SOME SHOWER
ACTIVITY DEVELOPING DURING THAT TIME. IN THE LAST HOUR...PRECIP
COVERAGE AND UPDRAFT INTENSITY HAVE ALREADY BEGUN DIMINISHING OR
WEAKENING RESPECTIVELY. RADAR LOOPS SHOW VARIOUS OUTFLOW
BOUNDARIES MOVING NORTH ACROSS OUR COUNTIES...AND MAY END UP BEING
A FOCUS FOR EVENING SHOWERS ALONG AND NORTH OF I-72.
STILL...COVERAGE WILL BE ISOLATED IN GENERAL.

FRIDAY MORNING...THE LOCATION OF THE BEST INSTABILITY WILL BE
ALONG AND NORTH OF I-74...SO ANY MORNING CONVECTION ON FRIDAY MAY
BE FOCUSED IN THAT AREA. DURING THE AFTERNOON...AN UPPER LOW
PRESSURE WAVE IS FORECAST TO LIFT NORTHEAST ACROSS IL...IN CONCERT
WITH INCREASING MOISTURE AND INSTABILITY AS THE STATIONARY FRONT
OSCILLATES NORTHWARD WITH THE WAVE. COVERAGE OF STORMS SHOULD BE
MORE THAN TODAY...BASED ON THE SUPPORT OF THE UPPER WAVE AND JET
DYNAMICS. ANY SUNSHINE THAT HEATS UP THE BOUNDARY LAYER WILL HELP
TO CREATE A FEW STRONG UPDRAFTS WITH SMALL HAIL, GUSTY WINDS, AND
VERY HEAVY RAINFALL.

THE STORMS MAY LINGER INTO THE EVENING EAST OF I-57...BUT SHOULD
DIMINISH BY MIDNIGHT. BY 12Z SAT MORNING...THE UPPER LOW IS
FORECAST TO BE CENTERED IN SOUTHERN INDIANA...WHICH WILL HELP PUT
PRECIP CHANCES MAINLY IN OUR SOUTHEAST COUNTIES ALONG AND SOUTHEAST
OF A LINE FROM SHELBYVILLE TO PARIS. THE SLOW DEPARTURE OF THE LOW
WILL KEEP CHANCES OF SHOWERS AND STORMS THROUGH SATURDAY AFTERNOON
IN THE SOUTHEAST.

THE WARM FRONT DEPARTING INTO NORTHERN IL FOLLOWED BY RIDGING AT
THE SURFACE AND ALOFT SATURDAY NIGHT AND SUNDAY SHOULD HELP MAKE
MOST AREAS DRY FOR THE LAST HALF OF THE WEEKEND. THE ADDITIONAL
SUNSHINE ON SUNDAY ALONG WITH DEEPER WARM AIR WILL HELP PUSH HIGH
TEMPS INTO THE MID TO UPPER 80S...WITH MUGGY DEWPOINTS IN THE
UPPER 60S TO NEAR 70. HEAT INDEX READINGS SUNDAY AFTERNOON WILL
CLIMB INTO THE 90S.

LONG TERM...MONDAY THROUGH THURSDAY.

ON MONDAY...AN OCCLUDING LOW PRESSURE PRESSURE SYSTEM IN THE
EASTERN DAKOTAS WILL CREATE SOME WARM FRONTOGENESIS TO THE
SOUTHEAST OF THE LOW ACROSS OUR NORTHERN COUNTIES. THAT WILL
CREATE A FOCUS FOR CONVECTION BY MONDAY AFTERNOON. MONDAY
NIGHT...A COLD FRONT WILL MOVE ACROSS IL PRODUCING STRONG TO
SEVERE STORMS AS ML-CAPE VALUES CLIMB TO NEAR 2K J/KG. BULK SHEAR
IS EXPECTED TO REACH OVER 40KT AS WELL...SO EMBEDDED SUPERCELLS
WILL BE POSSIBLE IN THE LINE OF STORMS THAT MOVES THROUGH.

STORMS ARE EXPECTED TO LINGER INTO TUESDAY AS THE UPPER COLD POOL
SLOWLY MAKES PROGRESS INTO ILLINOIS. WE KEPT LIKELY POPS SOUTHEAST
OF I-72...AND CHANCE ELSEWHERE. TUESDAY NIGHT PRECIP COVERAGE
SHOULD DIMINISH...WITH CHANCE POPS STILL IN PLACE ACROSS THE
BOARD. AN ELONGATED SURFACE TROUGH IS PROJECTED TO LINGER ACROSS
NORTHERN ILLINOIS INTO WED AS THE OCCLUDED UPPER LOW BECOMES MORE
OF AN OPEN WAVE AND SEND A SURFACE LOW EASTWARD ACROSS WISCONSIN.
THAT PROGRESSION WILL KEEP SCATTERED SHOWERS POSSIBLE AS FAR
SOUTH AS CENTRAL ILLINOIS THROUGH THURSDAY...ESPECIALLY EAST OF
I-55. PRECIP AMOUNTS MID WEEK SHOULD REMAIN LIGHT...BUT STILL
CLOUDS AND COOLER AIR WILL KEEP HIGH TEMPS BACK IN THE
70S...CLOSER TO NORMAL.

&&

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

$$

000
FXUS63 KILX 162335
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
635 PM CDT THU MAY 16 2013

.DISCUSSION...
ISSUED 300 PM CDT THU MAY 16 2013

A STATIONARY FRONT WILL OSCILLATE NORTH AND SOUTH ACROSS ILLINOIS
OVER THE NEXT DAY AND A HALF...THEN THE FRONT SHOULD LIFT NORTH AS
A WARM FRONT FOR THE WEEKEND...PUSHING HIGHS INTO THE MID TO UPPER
80S BY SUNDAY. BANDS OF THUNDERSTORMS THAT DEVELOP THROUGH
TOMORROW WILL LIKELY BE SLOW MOVING, HEAVY RAIN PRODUCERS LIKE
TODAY`S STORMS. LOCALIZED AREAS COULD SEE SIGNIFICANT RAINFALL OF
2-3 INCHES IN A COUPLE HOURS WHILE NEARBY AREAS SEE LITTLE RAIN.
PINPOINTING THAT ACTIVITY WILL BE DIFFICULT...BUT DIURNAL TRENDS
SHOULD PUT MOST OF THE CONVECTION DURING THE AFTERNOON
TOMORROW...ESPECIALLY NEAR ANY OUTFLOW BOUNDARIES SET DOWN BY
TODAY`S STORMS.

A SLIGHT LULL IN STORMS SHOULD OCCUR THIS WEEKEND AS RIDGING IN
THE PLAINS BUILDS INTO IL. A STRONGER COLD FRONT IS EXPECTED TO
PUSH ACROSS IL ON MONDAY AND MONDAY NIGHT...BRINGING OUR BETTER
CHANCES OF THUNDERSTORMS. WE ARE IN THE SPC DAY 5 OUTLOOK FOR
STRONG TO SEVERE STORMS MON-MON NIGHT. A COOL DOWN IS PROJECTED
FOR TUES THROUGH THURSDAY BEHIND THE COLD FRONT...PULLING HIGHS
BACK INTO THE 70S...BUT STILL AT OR ABOVE NORMAL.

SHORT TERM...TONIGHT THROUGH SUNDAY.

SHOWERS AND STORMS WILL GENERALLY BE DIMINISHING AS WE HEAD INTO
THE EVENING. THE LINE OF CONVECTION MAINLY CENTERED ON A LINE
FROM RUSHVILLE TO TAYLORVILLE TO EFFINGHAM TO LAWRENCEVILLE...IS
EXPECTED TO LIFT NORTH THIS EVENING. THE RAP MODEL IS SHOWING THE
INSTABILITY AXIS FOLLOWING THE SAME PROGRESSION...WITH SOME SHOWER
ACTIVITY DEVELOPING DURING THAT TIME. IN THE LAST HOUR...PRECIP
COVERAGE AND UPDRAFT INTENSITY HAVE ALREADY BEGUN DIMINISHING OR
WEAKENING RESPECTIVELY. RADAR LOOPS SHOW VARIOUS OUTFLOW
BOUNDARIES MOVING NORTH ACROSS OUR COUNTIES...AND MAY END UP BEING
A FOCUS FOR EVENING SHOWERS ALONG AND NORTH OF I-72.
STILL...COVERAGE WILL BE ISOLATED IN GENERAL.

FRIDAY MORNING...THE LOCATION OF THE BEST INSTABILITY WILL BE
ALONG AND NORTH OF I-74...SO ANY MORNING CONVECTION ON FRIDAY MAY
BE FOCUSED IN THAT AREA. DURING THE AFTERNOON...AN UPPER LOW
PRESSURE WAVE IS FORECAST TO LIFT NORTHEAST ACROSS IL...IN CONCERT
WITH INCREASING MOISTURE AND INSTABILITY AS THE STATIONARY FRONT
OSCILLATES NORTHWARD WITH THE WAVE. COVERAGE OF STORMS SHOULD BE
MORE THAN TODAY...BASED ON THE SUPPORT OF THE UPPER WAVE AND JET
DYNAMICS. ANY SUNSHINE THAT HEATS UP THE BOUNDARY LAYER WILL HELP
TO CREATE A FEW STRONG UPDRAFTS WITH SMALL HAIL, GUSTY WINDS, AND
VERY HEAVY RAINFALL.

THE STORMS MAY LINGER INTO THE EVENING EAST OF I-57...BUT SHOULD
DIMINISH BY MIDNIGHT. BY 12Z SAT MORNING...THE UPPER LOW IS
FORECAST TO BE CENTERED IN SOUTHERN INDIANA...WHICH WILL HELP PUT
PRECIP CHANCES MAINLY IN OUR SOUTHEAST COUNTIES ALONG AND SOUTHEAST
OF A LINE FROM SHELBYVILLE TO PARIS. THE SLOW DEPARTURE OF THE LOW
WILL KEEP CHANCES OF SHOWERS AND STORMS THROUGH SATURDAY AFTERNOON
IN THE SOUTHEAST.

THE WARM FRONT DEPARTING INTO NORTHERN IL FOLLOWED BY RIDGING AT
THE SURFACE AND ALOFT SATURDAY NIGHT AND SUNDAY SHOULD HELP MAKE
MOST AREAS DRY FOR THE LAST HALF OF THE WEEKEND. THE ADDITIONAL
SUNSHINE ON SUNDAY ALONG WITH DEEPER WARM AIR WILL HELP PUSH HIGH
TEMPS INTO THE MID TO UPPER 80S...WITH MUGGY DEWPOINTS IN THE
UPPER 60S TO NEAR 70. HEAT INDEX READINGS SUNDAY AFTERNOON WILL
CLIMB INTO THE 90S.

LONG TERM...MONDAY THROUGH THURSDAY.

ON MONDAY...AN OCCLUDING LOW PRESSURE PRESSURE SYSTEM IN THE
EASTERN DAKOTAS WILL CREATE SOME WARM FRONTOGENESIS TO THE
SOUTHEAST OF THE LOW ACROSS OUR NORTHERN COUNTIES. THAT WILL
CREATE A FOCUS FOR CONVECTION BY MONDAY AFTERNOON. MONDAY
NIGHT...A COLD FRONT WILL MOVE ACROSS IL PRODUCING STRONG TO
SEVERE STORMS AS ML-CAPE VALUES CLIMB TO NEAR 2K J/KG. BULK SHEAR
IS EXPECTED TO REACH OVER 40KT AS WELL...SO EMBEDDED SUPERCELLS
WILL BE POSSIBLE IN THE LINE OF STORMS THAT MOVES THROUGH.

STORMS ARE EXPECTED TO LINGER INTO TUESDAY AS THE UPPER COLD POOL
SLOWLY MAKES PROGRESS INTO ILLINOIS. WE KEPT LIKELY POPS SOUTHEAST
OF I-72...AND CHANCE ELSEWHERE. TUESDAY NIGHT PRECIP COVERAGE
SHOULD DIMINISH...WITH CHANCE POPS STILL IN PLACE ACROSS THE
BOARD. AN ELONGATED SURFACE TROUGH IS PROJECTED TO LINGER ACROSS
NORTHERN ILLINOIS INTO WED AS THE OCCLUDED UPPER LOW BECOMES MORE
OF AN OPEN WAVE AND SEND A SURFACE LOW EASTWARD ACROSS WISCONSIN.
THAT PROGRESSION WILL KEEP SCATTERED SHOWERS POSSIBLE AS FAR
SOUTH AS CENTRAL ILLINOIS THROUGH THURSDAY...ESPECIALLY EAST OF
I-55. PRECIP AMOUNTS MID WEEK SHOULD REMAIN LIGHT...BUT STILL
CLOUDS AND COOLER AIR WILL KEEP HIGH TEMPS BACK IN THE
70S...CLOSER TO NORMAL.



&&

.AVIATION...
ISSUED 635 PM CDT THU MAY 16 2013

MAIN AVIATION FORECAST CHALLENGE WILL BE TRYING TO PINPOINT TIMING
OF POTENTIAL CONVECTION OVER THE NEXT 24 HOURS. MESOSCALE OUTFLOW
BOUNDARY FROM STORMS ACROSS SOUTH-CENTRAL/SOUTHEAST ILLINOIS
EARLIER TODAY HAS DRIFTED NORTH OF THE I-74 TERMINALS...RESULTING
IN A RATHER STABLE ENVIRONMENT ACROSS MUCH OF CENTRAL ILLINOIS
EARLY THIS EVENING. WILL HAVE TO KEEP AN EYE ON A CU-FIELD ALONG
THE DISSIPATING OUTFLOW JUST NORTH OF KPIA AND KBMI...AS 21Z HRRR
TRIES TO FIRE SCATTERED STORMS IN THIS GENERAL AREA AFTER 03Z. AT
THIS POINT...WILL LEAVE THUNDER MENTION OUT OF THE TAFS THROUGH
TONIGHT. UPPER LOW CURRENTLY SPINNING OVER THE OZARKS WILL PIVOT
NORTHEASTWARD ON FRIDAY...SPREADING DEEPER MOISTURE NORTHWARD INTO
THE AREA. WILL THEREFORE INTRODUCE VCTS AT KSPI AND KDEC AFTER
14Z...THEN FURTHER NORTH INTO KPIA BY 17Z. WINDS WILL INITIALLY BE
FROM THE S/SW...THEN WILL BACK TO SE BY MID TO LATE EVENING. WITH
LIGHT WINDS EXPECTED OVERNIGHT...FORECAST SOUNDINGS ARE SUGGESTING
THE POTENTIAL FOR FOG DEVELOPMENT. WILL REDUCE VISBYS TO BETWEEN 4
AND 5SM AFTER 07Z ACCORDINGLY.

BARNES
&&

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

$$

000
FXUS63 KILX 162011
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
311 PM CDT THU MAY 16 2013

.DISCUSSION...
ISSUED 300 PM CDT THU MAY 16 2013

A STATIONARY FRONT WILL OSCILLATE NORTH AND SOUTH ACROSS ILLINOIS
OVER THE NEXT DAY AND A HALF...THEN THE FRONT SHOULD LIFT NORTH AS
A WARM FRONT FOR THE WEEKEND...PUSHING HIGHS INTO THE MID TO UPPER
80S BY SUNDAY. BANDS OF THUNDERSTORMS THAT DEVELOP THROUGH
TOMORROW WILL LIKELY BE SLOW MOVING, HEAVY RAIN PRODUCERS LIKE
TODAY`S STORMS. LOCALIZED AREAS COULD SEE SIGNIFICANT RAINFALL OF
2-3 INCHES IN A COUPLE HOURS WHILE NEARBY AREAS SEE LITTLE RAIN.
PINPOINTING THAT ACTIVITY WILL BE DIFFICULT...BUT DIURNAL TRENDS
SHOULD PUT MOST OF THE CONVECTION DURING THE AFTERNOON
TOMORROW...ESPECIALLY NEAR ANY OUTFLOW BOUNDARIES SET DOWN BY
TODAY`S STORMS.

A SLIGHT LULL IN STORMS SHOULD OCCUR THIS WEEKEND AS RIDGING IN
THE PLAINS BUILDS INTO IL. A STRONGER COLD FRONT IS EXPECTED TO
PUSH ACROSS IL ON MONDAY AND MONDAY NIGHT...BRINGING OUR BETTER
CHANCES OF THUNDERSTORMS. WE ARE IN THE SPC DAY 5 OUTLOOK FOR
STRONG TO SEVERE STORMS MON-MON NIGHT. A COOL DOWN IS PROJECTED
FOR TUES THROUGH THURSDAY BEHIND THE COLD FRONT...PULLING HIGHS
BACK INTO THE 70S...BUT STILL AT OR ABOVE NORMAL.

SHORT TERM...TONIGHT THROUGH SUNDAY.

SHOWERS AND STORMS WILL GENERALLY BE DIMINISHING AS WE HEAD INTO
THE EVENING. THE LINE OF CONVECTION MAINLY CENTERED ON A LINE
FROM RUSHVILLE TO TAYLORVILLE TO EFFINGHAM TO LAWRENCEVILLE...IS
EXPECTED TO LIFT NORTH THIS EVENING. THE RAP MODEL IS SHOWING THE
INSTABILITY AXIS FOLLOWING THE SAME PROGRESSION...WITH SOME SHOWER
ACTIVITY DEVELOPING DURING THAT TIME. IN THE LAST HOUR...PRECIP
COVERAGE AND UPDRAFT INTENSITY HAVE ALREADY BEGUN DIMINISHING OR
WEAKENING RESPECTIVELY. RADAR LOOPS SHOW VARIOUS OUTFLOW
BOUNDARIES MOVING NORTH ACROSS OUR COUNTIES...AND MAY END UP BEING
A FOCUS FOR EVENING SHOWERS ALONG AND NORTH OF I-72.
STILL...COVERAGE WILL BE ISOLATED IN GENERAL.

FRIDAY MORNING...THE LOCATION OF THE BEST INSTABILITY WILL BE
ALONG AND NORTH OF I-74...SO ANY MORNING CONVECTION ON FRIDAY MAY
BE FOCUSED IN THAT AREA. DURING THE AFTERNOON...AN UPPER LOW
PRESSURE WAVE IS FORECAST TO LIFT NORTHEAST ACROSS IL...IN CONCERT
WITH INCREASING MOISTURE AND INSTABILITY AS THE STATIONARY FRONT
OSCILLATES NORTHWARD WITH THE WAVE. COVERAGE OF STORMS SHOULD BE
MORE THAN TODAY...BASED ON THE SUPPORT OF THE UPPER WAVE AND JET
DYNAMICS. ANY SUNSHINE THAT HEATS UP THE BOUNDARY LAYER WILL HELP
TO CREATE A FEW STRONG UPDRAFTS WITH SMALL HAIL, GUSTY WINDS, AND
VERY HEAVY RAINFALL.

THE STORMS MAY LINGER INTO THE EVENING EAST OF I-57...BUT SHOULD
DIMINISH BY MIDNIGHT. BY 12Z SAT MORNING...THE UPPER LOW IS
FORECAST TO BE CENTERED IN SOUTHERN INDIANA...WHICH WILL HELP PUT
PRECIP CHANCES MAINLY IN OUR SOUTHEAST COUNTIES ALONG AND SOUTHEAST
OF A LINE FROM SHELBYVILLE TO PARIS. THE SLOW DEPARTURE OF THE LOW
WILL KEEP CHANCES OF SHOWERS AND STORMS THROUGH SATURDAY AFTERNOON
IN THE SOUTHEAST.

THE WARM FRONT DEPARTING INTO NORTHERN IL FOLLOWED BY RIDGING AT
THE SURFACE AND ALOFT SATURDAY NIGHT AND SUNDAY SHOULD HELP MAKE
MOST AREAS DRY FOR THE LAST HALF OF THE WEEKEND. THE ADDITIONAL
SUNSHINE ON SUNDAY ALONG WITH DEEPER WARM AIR WILL HELP PUSH HIGH
TEMPS INTO THE MID TO UPPER 80S...WITH MUGGY DEWPOINTS IN THE
UPPER 60S TO NEAR 70. HEAT INDEX READINGS SUNDAY AFTERNOON WILL
CLIMB INTO THE 90S.

LONG TERM...MONDAY THROUGH THURSDAY.

ON MONDAY...AN OCCLUDING LOW PRESSURE PRESSURE SYSTEM IN THE
EASTERN DAKOTAS WILL CREATE SOME WARM FRONTOGENESIS TO THE
SOUTHEAST OF THE LOW ACROSS OUR NORTHERN COUNTIES. THAT WILL
CREATE A FOCUS FOR CONVECTION BY MONDAY AFTERNOON. MONDAY
NIGHT...A COLD FRONT WILL MOVE ACROSS IL PRODUCING STRONG TO
SEVERE STORMS AS ML-CAPE VALUES CLIMB TO NEAR 2K J/KG. BULK SHEAR
IS EXPECTED TO REACH OVER 40KT AS WELL...SO EMBEDDED SUPERCELLS
WILL BE POSSIBLE IN THE LINE OF STORMS THAT MOVES THROUGH.

STORMS ARE EXPECTED TO LINGER INTO TUESDAY AS THE UPPER COLD POOL
SLOWLY MAKES PROGRESS INTO ILLINOIS. WE KEPT LIKELY POPS SOUTHEAST
OF I-72...AND CHANCE ELSEWHERE. TUESDAY NIGHT PRECIP COVERAGE
SHOULD DIMINISH...WITH CHANCE POPS STILL IN PLACE ACROSS THE
BOARD. AN ELONGATED SURFACE TROUGH IS PROJECTED TO LINGER ACROSS
NORTHERN ILLINOIS INTO WED AS THE OCCLUDED UPPER LOW BECOMES MORE
OF AN OPEN WAVE AND SEND A SURFACE LOW EASTWARD ACROSS WISCONSIN.
THAT PROGRESSION WILL KEEP SCATTERED SHOWERS POSSIBLE AS FAR
SOUTH AS CENTRAL ILLINOIS THROUGH THURSDAY...ESPECIALLY EAST OF
I-55. PRECIP AMOUNTS MID WEEK SHOULD REMAIN LIGHT...BUT STILL
CLOUDS AND COOLER AIR WILL KEEP HIGH TEMPS BACK IN THE
70S...CLOSER TO NORMAL.

SHIMON
&&

.AVIATION...
ISSUED 1225 PM CDT THU MAY 16 2013

POP-UP NATURE OF SHOWERS/STORMS THIS AFTERNOON WILL BE A CHALLENGE
IN GOING WITH ANYTHING MORE THAN VCTS. ONE LINE OF STORMS WAS
LOCATED JUST SOUTH OF KSPI/KTAZ BUT REMAINING STATIONARY...SO WILL
NOT ADD A PREVAILING TSRA AT KSPI YET. MANY OF THE STORMS SHOULD
FADE WITH SUNSET...AND HAVE GONE WITH LARGELY DRY CONDITIONS AT
ALL TAF SITES MUCH OF THE NIGHT. LATEST HIGH- RESOLUTION GUIDANCE
SUGGESTING SOME LATE NIGHT DEVELOPMENT NEAR KPIA/KBMI...AND HAVE
PUT SOME VCTS BACK THERE...ALTHOUGH MAIN CONCERN LATE NIGHT WILL
BE WITH AREAS OF MVFR FOG. ON FRIDAY MORNING...POTENTIAL EXISTS
FOR ADDITIONAL SHOWERS/STORMS TO LIFT UP FROM THE SOUTH...AND HAVE
MENTIONED VCTS AT KSPI/KDEC AFTER 15Z.

GEELHART
&&

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

$$

000
FXUS63 KILX 161726
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1226 PM CDT THU MAY 16 2013

.DISCUSSION...
ISSUED 937 AM CDT THU MAY 16 2013

DIFFUSE FRONTAL BOUNDARY WAS ROUGHLY CENTERED ALONG THE I-72
CORRIDOR THIS MORNING. HAVE MAINLY HAD SOME POP-UP TYPE SHOWERS
AND STORMS ALONG THE BOUNDARY OVER THE LAST COUPLE HOURS...WITH A
MORE ORGANIZED BAND OF SHOWERS ACROSS THE NORTHERN CWA
DISSIPATING. GREATEST ACTION HAS BEEN LIFTING OUT OF SOUTHERN
ILLINOIS AND SCRAPING THE FAR SOUTHEAST CWA.

NOT TOO MUCH CHANGE FROM EARLIER THINKING ABOUT PLACEMENT OF
SHOWERS AND STORMS TODAY. HAVE SENT SOME UPDATED GRIDS AND ZONES
TO ADJUST THE WINDS BASED ON THE LATEST LOCATION OF THE BOUNDARY.
LITTLE ADJUSTMENT NEEDED TO TEMPERATURES OR PRECIP CHANCES...
ALTHOUGH SOME CHANGES IN THE GRIDS WERE MADE IN THE FAR SOUTHEAST
TO BOOST POPS DUE TO ONGOING CONVECTION.

GEELHART


&&

.AVIATION...
ISSUED 1225 PM CDT THU MAY 16 2013

POP-UP NATURE OF SHOWERS/STORMS THIS AFTERNOON WILL BE A CHALLENGE
IN GOING WITH ANYTHING MORE THAN VCTS. ONE LINE OF STORMS WAS
LOCATED JUST SOUTH OF KSPI/KTAZ BUT REMAINING STATIONARY...SO WILL
NOT ADD A PREVAILING TSRA AT KSPI YET. MANY OF THE STORMS SHOULD
FADE WITH SUNSET...AND HAVE GONE WITH LARGELY DRY CONDITIONS AT
ALL TAF SITES MUCH OF THE NIGHT. LATEST HIGH- RESOLUTION GUIDANCE
SUGGESTING SOME LATE NIGHT DEVELOPMENT NEAR KPIA/KBMI...AND HAVE
PUT SOME VCTS BACK THERE...ALTHOUGH MAIN CONCERN LATE NIGHT WILL
BE WITH AREAS OF MVFR FOG. ON FRIDAY MORNING...POTENTIAL EXISTS
FOR ADDITIONAL SHOWERS/STORMS TO LIFT UP FROM THE SOUTH...AND HAVE
MENTIONED VCTS AT KSPI/KDEC AFTER 15Z.

GEELHART

&&

.PREV DISCUSSION...
ISSUED 319 AM CDT THU MAY 16 2013

SHORT TERM...TODAY THROUGH FRIDAY

QUASI-STATIONARY FRONT LIES WEST-EAST ACROSS CENTRAL IL EARLY
THIS MORNING BUT HAS BECOME ILL DEFINED DUE TO CONVECTION AND
RESULTING OUTFLOW BOUNDARIES. BEST COVERAGE OF THUNDERSTORMS FOR
PAST FEW HOURS HAS OCCURRED OVER THE NORTHERN THIRD OF THE CWA
WHERE A 30 KT WSW LOW LEVEL JET HAS PROVIDED ENHANCED CONVERGENCE
INTO THE LOW AND MID LEVEL BOUNDARIES. THIS ACTIVITY WILL CONTINUE
TO FADE TOWARDS SUNRISE AS THE LLJ WEAKENS. MAIN FORECAST
CHALLENGE TODAY WILL BE COVERAGE AND TIMING OF TSTMS WITH BOUNDARY
REMAINING IN THE AREA...AND A CLOSED UPPER LOW CURRENTLY OVER
OKLAHOMA WHICH WILL BE OPENING UP AND LIFTING NORTHEAST. MOISTURE
LEVELS INCREASE AHEAD OF THIS FEATURE SO EXPECT BETTER STORM
COVERAGE THAN YESTERDAY ESPECIALLY DURING PEAK AFTERNOON
INSTABILITY. LATEST HI-RES SHORT RANGE MODELS FOCUS THIS ACTIVITY
OVER THE CENTRAL AND SOUTHERN CWA AND HAVE PLACED HIGHEST CHANCE
POPS HERE.  FORECAST SOUNDINGS SHOW ENOUGH MID LEVEL COOLING TO
ERODE CAPPING...AND AFTERNOON/EARLY EVENING CAPES ON THE ORDER OF
1K J/KG. WINDS ALOFT ARE QUITE LIGHT NEAR 10 KTS SO STORMS WILL BE
SLOW MOVERS AND CAPABLE OF HEAVY RAIN RATES AS PRECIPITABLE WATER
RISES TO AROUND 1.25 INCHES. STORMS SHOULD DISSIPATE DURING THE
EVENING WITH LOSS OF DAYTIME HEATING AND NO LLJ SUPPORT.

THE BOUNDARY LIFTS NORTH OF THE CWA ON FRIDAY...BUT
MORE SCATTERED AFTERNOON CONVECTION EXPECTED AS THE UPPER TROF
SHIFTS ACROSS THE AREA. TEMPS WILL REMAIN SEVERAL DEGREES ABOVE
NORMAL FOR THE NEXT COUPLE DAYS WITH HIGHS IN THE LOWER 80S AND
LOWS IN THE LOWER 60S.

LONG TERM...SATURDAY THROUGH WEDNESDAY

LINGERING EFFECTS OF THE UPPER TROF COULD BRING SCATTERED
CONVECTION BACK TO PRIMARILY THE EASTERN CWA SATURDAY
AFTERNOON...CLOSER TO THE DEPARTING TROF. BY LATE SATURDAY INTO
SUNDAY UPPER RIDGING WILL BUILD ACROSS THE MISSISSIPPI VALLEY IN
RESPONSE TO THE NEXT SYSTEM DEVELOPING OVER THE ROCKIES. THIS
PROVIDES THE BEST SHOT AT A DRY PERIOD IN THE FORECAST AND HAVE
REMOVED ANY MENTIONABLE POPS SATURDAY NIGHT THROUGH SUNDAY
AFTERNOON. SUNDAY HAS THE POTENTIAL TO BE THE WARMEST OF THE NEXT
7 DAYS AS 850MB TEMPS WARM INTO THE UPPER TEENS AND AMPLE
SUNSHINE. HAVE BOOSTED HIGHS IN TO THE MID 80S.

A DEEP UPPER LOW IS FORECAST TO CLOSE OFF OVER THE NORTHERN PLAINS
BY THE END OF THE WEEKEND...AND SLOWLY MOVE TOWARDS THE WESTERN
GREAT LAKES BY WEDNESDAY ACCORDING TO THE GFS...OR OVER THE CWA
ACCORDING TO THE 00Z ECMWF. IN EITHER CASE THIS SETS UP A
PROLONGED PERIOD OF DIFFLUENT SOUTHWEST MID LEVEL OVER THE MIDWEST
FROM SUNDAY NIGHT...THROUGH AT LEAST TUESDAY. GULF MOISTURE WILL
HAVE OVERSPREAD THE MIDWEST BY THIS TIME...AND WITH SHORTWAVES
RIPPLING OVER THE AREA SCATTERED CONVECTION WILL BE AROUND FROM
TIME TO TIME. HAVE CHANCE POPS IN THE REMAINDER OF THE EXTENDED
AND WHILE CERTAINLY MANY HOURS WILL BE DRY...IMPOSSIBLE TO TIME AT
THIS POINT. STRONG OR SEVERE STORMS MAY BE POSSIBLE DEPENDING ON
INSTABILITY...BUT WITH A DEEPLY OCCLUDED SYSTEM THIS SCENARIO IS
NOT AS WELL DEFINED AS 24 HOURS AGO. TEMPERATURES WILL REMAIN WELL
ABOVE NORMAL UNTIL THE LONGWAVE TROF CAN SHIFT THROUGH WHICH MAY
NOT BE UNTIL THE END OF THE FORECAST PERIOD OR LATER.

25


&&

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

$$

000
FXUS63 KILX 161437
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
937 AM CDT THU MAY 16 2013

.DISCUSSION...
ISSUED 937 AM CDT THU MAY 16 2013

DIFFUSE FRONTAL BOUNDARY WAS ROUGHLY CENTERED ALONG THE I-72
CORRIDOR THIS MORNING. HAVE MAINLY HAD SOME POP-UP TYPE SHOWERS
AND STORMS ALONG THE BOUNDARY OVER THE LAST COUPLE HOURS...WITH A
MORE ORGANIZED BAND OF SHOWERS ACROSS THE NORTHERN CWA
DISSIPATING. GREATEST ACTION HAS BEEN LIFTING OUT OF SOUTHERN
ILLINOIS AND SCRAPING THE FAR SOUTHEAST CWA.

NOT TOO MUCH CHANGE FROM EARLIER THINKING ABOUT PLACEMENT OF
SHOWERS AND STORMS TODAY. HAVE SENT SOME UPDATED GRIDS AND ZONES
TO ADJUST THE WINDS BASED ON THE LATEST LOCATION OF THE BOUNDARY.
LITTLE ADJUSTMENT NEEDED TO TEMPERATURES OR PRECIP CHANCES...
ALTHOUGH SOME CHANGES IN THE GRIDS WERE MADE IN THE FAR SOUTHEAST
TO BOOST POPS DUE TO ONGOING CONVECTION.

GEELHART

&&

.AVIATION...
ISSUED 655 AM CDT THU MAY 16 2013

AN ILL DEFINED FRONTAL BOUNDARY LIES NEARLY WEST/EAST ACROSS
CENTRAL ILLINOIS THIS MORNING. A BROKEN BAND OF SHOWERS AND A FEW
THUNDERSTORMS HAS BEEN MOVING JUST NORTH OF AND NEARLY PARALLEL TO
THE FRONT. THIS PRECIPITATION HAS BEEN ON THE DECREASE OVERALL
WITH THE GRADUAL LOSS OF THE NOCTURNAL LOW LEVEL JET. EXPECT AN
INCREASE IN SHOWER/STORM COVERAGE THIS AFTERNOON AND EARLY
EVENING AS THE FRONT BEGINS A SLOW NORTHWARD PUSH LATER TODAY...
ALONG WITH A DIURNAL INCREASE IN INSTABILITY. HOWEVER...AT THIS
POINT...CONFIDENCE IN TIMING/COVERAGE OF THE PRECIPITATION IS TOO
LOW TO GO ABOVE A VICINITY MENTION. WINDS WILL BE FAIRLY LIGHT FOR
THE MOST PART...WITH THE MOST NOTABLE SHIFTS OCCURRING IN THE
VICINITY OF FROPA OR A STORM INDUCED GUST FRONT.

BAK

&&

.PREV DISCUSSION...
ISSUED 319 AM CDT THU MAY 16 2013

SHORT TERM...TODAY THROUGH FRIDAY

QUASI-STATIONARY FRONT LIES WEST-EAST ACROSS CENTRAL IL EARLY
THIS MORNING BUT HAS BECOME ILL DEFINED DUE TO CONVECTION AND
RESULTING OUTFLOW BOUNDARIES. BEST COVERAGE OF THUNDERSTORMS FOR
PAST FEW HOURS HAS OCCURRED OVER THE NORTHERN THIRD OF THE CWA
WHERE A 30 KT WSW LOW LEVEL JET HAS PROVIDED ENHANCED CONVERGENCE
INTO THE LOW AND MID LEVEL BOUNDARIES. THIS ACTIVITY WILL CONTINUE
TO FADE TOWARDS SUNRISE AS THE LLJ WEAKENS. MAIN FORECAST
CHALLENGE TODAY WILL BE COVERAGE AND TIMING OF TSTMS WITH BOUNDARY
REMAINING IN THE AREA...AND A CLOSED UPPER LOW CURRENTLY OVER
OKLAHOMA WHICH WILL BE OPENING UP AND LIFTING NORTHEAST. MOISTURE
LEVELS INCREASE AHEAD OF THIS FEATURE SO EXPECT BETTER STORM
COVERAGE THAN YESTERDAY ESPECIALLY DURING PEAK AFTERNOON
INSTABILITY. LATEST HI-RES SHORT RANGE MODELS FOCUS THIS ACTIVITY
OVER THE CENTRAL AND SOUTHERN CWA AND HAVE PLACED HIGHEST CHANCE
POPS HERE.  FORECAST SOUNDINGS SHOW ENOUGH MID LEVEL COOLING TO
ERODE CAPPING...AND AFTERNOON/EARLY EVENING CAPES ON THE ORDER OF
1K J/KG. WINDS ALOFT ARE QUITE LIGHT NEAR 10 KTS SO STORMS WILL BE
SLOW MOVERS AND CAPABLE OF HEAVY RAIN RATES AS PRECIPITABLE WATER
RISES TO AROUND 1.25 INCHES. STORMS SHOULD DISSIPATE DURING THE
EVENING WITH LOSS OF DAYTIME HEATING AND NO LLJ SUPPORT.

THE BOUNDARY LIFTS NORTH OF THE CWA ON FRIDAY...BUT
MORE SCATTERED AFTERNOON CONVECTION EXPECTED AS THE UPPER TROF
SHIFTS ACROSS THE AREA. TEMPS WILL REMAIN SEVERAL DEGREES ABOVE
NORMAL FOR THE NEXT COUPLE DAYS WITH HIGHS IN THE LOWER 80S AND
LOWS IN THE LOWER 60S.

LONG TERM...SATURDAY THROUGH WEDNESDAY

LINGERING EFFECTS OF THE UPPER TROF COULD BRING SCATTERED
CONVECTION BACK TO PRIMARILY THE EASTERN CWA SATURDAY
AFTERNOON...CLOSER TO THE DEPARTING TROF. BY LATE SATURDAY INTO
SUNDAY UPPER RIDGING WILL BUILD ACROSS THE MISSISSIPPI VALLEY IN
RESPONSE TO THE NEXT SYSTEM DEVELOPING OVER THE ROCKIES. THIS
PROVIDES THE BEST SHOT AT A DRY PERIOD IN THE FORECAST AND HAVE
REMOVED ANY MENTIONABLE POPS SATURDAY NIGHT THROUGH SUNDAY
AFTERNOON. SUNDAY HAS THE POTENTIAL TO BE THE WARMEST OF THE NEXT
7 DAYS AS 850MB TEMPS WARM INTO THE UPPER TEENS AND AMPLE
SUNSHINE. HAVE BOOSTED HIGHS IN TO THE MID 80S.

A DEEP UPPER LOW IS FORECAST TO CLOSE OFF OVER THE NORTHERN PLAINS
BY THE END OF THE WEEKEND...AND SLOWLY MOVE TOWARDS THE WESTERN
GREAT LAKES BY WEDNESDAY ACCORDING TO THE GFS...OR OVER THE CWA
ACCORDING TO THE 00Z ECMWF. IN EITHER CASE THIS SETS UP A
PROLONGED PERIOD OF DIFFLUENT SOUTHWEST MID LEVEL OVER THE MIDWEST
FROM SUNDAY NIGHT...THROUGH AT LEAST TUESDAY. GULF MOISTURE WILL
HAVE OVERSPREAD THE MIDWEST BY THIS TIME...AND WITH SHORTWAVES
RIPPLING OVER THE AREA SCATTERED CONVECTION WILL BE AROUND FROM
TIME TO TIME. HAVE CHANCE POPS IN THE REMAINDER OF THE EXTENDED
AND WHILE CERTAINLY MANY HOURS WILL BE DRY...IMPOSSIBLE TO TIME AT
THIS POINT. STRONG OR SEVERE STORMS MAY BE POSSIBLE DEPENDING ON
INSTABILITY...BUT WITH A DEEPLY OCCLUDED SYSTEM THIS SCENARIO IS
NOT AS WELL DEFINED AS 24 HOURS AGO. TEMPERATURES WILL REMAIN WELL
ABOVE NORMAL UNTIL THE LONGWAVE TROF CAN SHIFT THROUGH WHICH MAY
NOT BE UNTIL THE END OF THE FORECAST PERIOD OR LATER.

25

&&

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

$$

000
FXUS63 KILX 161155
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
655 AM CDT THU MAY 16 2013

.DISCUSSION...
ISSUED 319 AM CDT THU MAY 16 2013

SHORT TERM...TODAY THROUGH FRIDAY

QUASI-STATIONARY FRONT LIES WEST-EAST ACROSS CENTRAL IL EARLY
THIS MORNING BUT HAS BECOME ILL DEFINED DUE TO CONVECTION AND
RESULTING OUTFLOW BOUNDARIES. BEST COVERAGE OF THUNDERSTORMS FOR
PAST FEW HOURS HAS OCCURRED OVER THE NORTHERN THIRD OF THE CWA
WHERE A 30 KT WSW LOW LEVEL JET HAS PROVIDED ENHANCED CONVERGENCE
INTO THE LOW AND MID LEVEL BOUNDARIES. THIS ACTIVITY WILL CONTINUE
TO FADE TOWARDS SUNRISE AS THE LLJ WEAKENS. MAIN FORECAST
CHALLENGE TODAY WILL BE COVERAGE AND TIMING OF TSTMS WITH BOUNDARY
REMAINING IN THE AREA...AND A CLOSED UPPER LOW CURRENTLY OVER
OKLAHOMA WHICH WILL BE OPENING UP AND LIFTING NORTHEAST. MOISTURE
LEVELS INCREASE AHEAD OF THIS FEATURE SO EXPECT BETTER STORM
COVERAGE THAN YESTERDAY ESPECIALLY DURING PEAK AFTERNOON
INSTABILITY. LATEST HI-RES SHORT RANGE MODELS FOCUS THIS ACTIVITY
OVER THE CENTRAL AND SOUTHERN CWA AND HAVE PLACED HIGHEST CHANCE
POPS HERE.  FORECAST SOUNDINGS SHOW ENOUGH MID LEVEL COOLING TO
ERODE CAPPING...AND AFTERNOON/EARLY EVENING CAPES ON THE ORDER OF
1K J/KG. WINDS ALOFT ARE QUITE LIGHT NEAR 10 KTS SO STORMS WILL BE
SLOW MOVERS AND CAPABLE OF HEAVY RAIN RATES AS PRECIPITABLE WATER
RISES TO AROUND 1.25 INCHES. STORMS SHOULD DISSIPATE DURING THE
EVENING WITH LOSS OF DAYTIME HEATING AND NO LLJ SUPPORT.

THE BOUNDARY LIFTS NORTH OF THE CWA ON FRIDAY...BUT
MORE SCATTERED AFTERNOON CONVECTION EXPECTED AS THE UPPER TROF
SHIFTS ACROSS THE AREA. TEMPS WILL REMAIN SEVERAL DEGREES ABOVE
NORMAL FOR THE NEXT COUPLE DAYS WITH HIGHS IN THE LOWER 80S AND
LOWS IN THE LOWER 60S.

LONG TERM...SATURDAY THROUGH WEDNESDAY

LINGERING EFFECTS OF THE UPPER TROF COULD BRING SCATTERED
CONVECTION BACK TO PRIMARILY THE EASTERN CWA SATURDAY
AFTERNOON...CLOSER TO THE DEPARTING TROF. BY LATE SATURDAY INTO
SUNDAY UPPER RIDGING WILL BUILD ACROSS THE MISSISSIPPI VALLEY IN
RESPONSE TO THE NEXT SYSTEM DEVELOPING OVER THE ROCKIES. THIS
PROVIDES THE BEST SHOT AT A DRY PERIOD IN THE FORECAST AND HAVE
REMOVED ANY MENTIONABLE POPS SATURDAY NIGHT THROUGH SUNDAY
AFTERNOON. SUNDAY HAS THE POTENTIAL TO BE THE WARMEST OF THE NEXT
7 DAYS AS 850MB TEMPS WARM INTO THE UPPER TEENS AND AMPLE
SUNSHINE. HAVE BOOSTED HIGHS IN TO THE MID 80S.

A DEEP UPPER LOW IS FORECAST TO CLOSE OFF OVER THE NORTHERN PLAINS
BY THE END OF THE WEEKEND...AND SLOWLY MOVE TOWARDS THE WESTERN
GREAT LAKES BY WEDNESDAY ACCORDING TO THE GFS...OR OVER THE CWA
ACCORDING TO THE 00Z ECMWF. IN EITHER CASE THIS SETS UP A
PROLONGED PERIOD OF DIFFLUENT SOUTHWEST MID LEVEL OVER THE MIDWEST
FROM SUNDAY NIGHT...THROUGH AT LEAST TUESDAY. GULF MOISTURE WILL
HAVE OVERSPREAD THE MIDWEST BY THIS TIME...AND WITH SHORTWAVES
RIPPLING OVER THE AREA SCATTERED CONVECTION WILL BE AROUND FROM
TIME TO TIME. HAVE CHANCE POPS IN THE REMAINDER OF THE EXTENDED
AND WHILE CERTAINLY MANY HOURS WILL BE DRY...IMPOSSIBLE TO TIME AT
THIS POINT. STRONG OR SEVERE STORMS MAY BE POSSIBLE DEPENDING ON
INSTABILITY...BUT WITH A DEEPLY OCCLUDED SYSTEM THIS SCENARIO IS
NOT AS WELL DEFINED AS 24 HOURS AGO. TEMPERATURES WILL REMAIN WELL
ABOVE NORMAL UNTIL THE LONGWAVE TROF CAN SHIFT THROUGH WHICH MAY
NOT BE UNTIL THE END OF THE FORECAST PERIOD OR LATER.

25
&&

.AVIATION...
ISSUED 655 AM CDT THU MAY 16 2013

AN ILL DEFINED FRONTAL BOUNDARY LIES NEARLY WEST/EAST ACROSS
CENTRAL ILLINOIS THIS MORNING. A BROKEN BAND OF SHOWERS AND A FEW
THUNDERSTORMS HAS BEEN MOVING JUST NORTH OF AND NEARLY PARALLEL TO
THE FRONT. THIS PRECIPITATION HAS BEEN ON THE DECREASE OVERALL
WITH THE GRADUAL LOSS OF THE NOCTURNAL LOW LEVEL JET. EXPECT AN
INCREASE IN SHOWER/STORM COVERAGE THIS AFTERNOON AND EARLY
EVENING AS THE FRONT BEGINS A SLOW NORTHWARD PUSH LATER TODAY...
ALONG WITH A DIURNAL INCREASE IN INSTABILITY. HOWEVER...AT THIS
POINT...CONFIDENCE IN TIMING/COVERAGE OF THE PRECIPITATION IS TOO
LOW TO GO ABOVE A VICINITY MENTION. WINDS WILL BE FAIRLY LIGHT FOR
THE MOST PART...WITH THE MOST NOTABLE SHIFTS OCCURRING IN THE
VICINITY OF FROPA OR A STORM INDUCED GUST FRONT.

BAK
&&

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

$$

000
FXUS63 KILX 160820
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
320 AM CDT THU MAY 16 2013

.DISCUSSION...
ISSUED 319 AM CDT THU MAY 16 2013

SHORT TERM...TODAY THROUGH FRIDAY

QUASI-STATIONARY FRONT LIES WEST-EAST ACROSS CENTRAL IL EARLY
THIS MORNING BUT HAS BECOME ILL DEFINED DUE TO CONVECTION AND
RESULTING OUTFLOW BOUNDARIES. BEST COVERAGE OF THUNDERSTORMS FOR
PAST FEW HOURS HAS OCCURRED OVER THE NORTHERN THIRD OF THE CWA
WHERE A 30 KT WSW LOW LEVEL JET HAS PROVIDED ENHANCED CONVERGENCE
INTO THE LOW AND MID LEVEL BOUNDARIES. THIS ACTIVITY WILL CONTINUE
TO FADE TOWARDS SUNRISE AS THE LLJ WEAKENS. MAIN FORECAST
CHALLENGE TODAY WILL BE COVERAGE AND TIMING OF TSTMS WITH BOUNDARY
REMAINING IN THE AREA...AND A CLOSED UPPER LOW CURRENTLY OVER
OKLAHOMA WHICH WILL BE OPENING UP AND LIFTING NORTHEAST. MOISTURE
LEVELS INCREASE AHEAD OF THIS FEATURE SO EXPECT BETTER STORM
COVERAGE THAN YESTERDAY ESPECIALLY DURING PEAK AFTERNOON
INSTABILITY. LATEST HI-RES SHORT RANGE MODELS FOCUS THIS ACTIVITY
OVER THE CENTRAL AND SOUTHERN CWA AND HAVE PLACED HIGHEST CHANCE
POPS HERE.  FORECAST SOUNDINGS SHOW ENOUGH MID LEVEL COOLING TO
ERODE CAPPING...AND AFTERNOON/EARLY EVENING CAPES ON THE ORDER OF
1K J/KG. WINDS ALOFT ARE QUITE LIGHT NEAR 10 KTS SO STORMS WILL BE
SLOW MOVERS AND CAPABLE OF HEAVY RAIN RATES AS PRECIPITABLE WATER
RISES TO AROUND 1.25 INCHES. STORMS SHOULD DISSIPATE DURING THE
EVENING WITH LOSS OF DAYTIME HEATING AND NO LLJ SUPPORT.

THE BOUNDARY LIFTS NORTH OF THE CWA ON FRIDAY...BUT
MORE SCATTERED AFTERNOON CONVECTION EXPECTED AS THE UPPER TROF
SHIFTS ACROSS THE AREA. TEMPS WILL REMAIN SEVERAL DEGREES ABOVE
NORMAL FOR THE NEXT COUPLE DAYS WITH HIGHS IN THE LOWER 80S AND
LOWS IN THE LOWER 60S.

LONG TERM...SATURDAY THROUGH WEDNESDAY

LINGERING EFFECTS OF THE UPPER TROF COULD BRING SCATTERED
CONVECTION BACK TO PRIMARILY THE EASTERN CWA SATURDAY
AFTERNOON...CLOSER TO THE DEPARTING TROF. BY LATE SATURDAY INTO
SUNDAY UPPER RIDGING WILL BUILD ACROSS THE MISSISSIPPI VALLEY IN
RESPONSE TO THE NEXT SYSTEM DEVELOPING OVER THE ROCKIES. THIS
PROVIDES THE BEST SHOT AT A DRY PERIOD IN THE FORECAST AND HAVE
REMOVED ANY MENTIONABLE POPS SATURDAY NIGHT THROUGH SUNDAY
AFTERNOON. SUNDAY HAS THE POTENTIAL TO BE THE WARMEST OF THE NEXT
7 DAYS AS 850MB TEMPS WARM INTO THE UPPER TEENS AND AMPLE
SUNSHINE. HAVE BOOSTED HIGHS IN TO THE MID 80S.

A DEEP UPPER LOW IS FORECAST TO CLOSE OFF OVER THE NORTHERN PLAINS
BY THE END OF THE WEEKEND...AND SLOWLY MOVE TOWARDS THE WESTERN
GREAT LAKES BY WEDNESDAY ACCORDING TO THE GFS...OR OVER THE CWA
ACCORDING TO THE 00Z ECMWF. IN EITHER CASE THIS SETS UP A
PROLONGED PERIOD OF DIFLUENT SOUTHWEST MID LEVEL OVER THE MIDWEST
FROM SUNDAY NIGHT...THROUGH AT LEAST TUESDAY. GULF MOISTURE WILL
HAVE OVERSPREAD THE MIDWEST BY THIS TIME...AND WITH SHORTWAVES
RIPPLING OVER THE AREA SCATTERED CONVECTION WILL BE AROUND FROM
TIME TO TIME. HAVE CHANCE POPS IN THE REMAINDER OF THE EXTENDED
AND WHILE CERTAINLY MANY HOURS WILL BE DRY...IMPOSSIBLE TO TIME AT
THIS POINT. STRONG OR SEVERE STORMS MAY BE POSSIBLE DEPENDING ON
INSTABILITY...BUT WITH A DEEPLY OCCLUDED SYSTEM THIS SCENARIO IS
NOT AS WELL DEFINED AS 24 HOURS AGO. TEMPERATURES WILL REMAIN WELL
ABOVE NORMAL UNTIL THE LONGWAVE TROF CAN SHIFT THROUGH WHICH MAY
NOT BE UNTIL THE END OF THE FORECAST PERIOD OR LATER.

25
&&

.AVIATION...
ISSUED 1142 PM CDT WED MAY 15 2013

STATIONARY FRONTAL BOUNDARY CURRENTLY DRAPED ACROSS THE AREA WILL
BE THE MAIN FOCUSING MECHANISM FOR WIDELY SCATTERED SHOWERS/THUNDER
THROUGH THE ENTIRE 06Z TAF PERIOD. LATEST RADAR IMAGERY SHOWS
SCATTERED CONVECTION IMMEDIATELY AHEAD OF THE FRONT SOUTH OF THE
I-72 CORRIDOR...WITH ANOTHER BROKEN LINE OF SHOWERS/STORMS
DEVELOPING FURTHER NORTH ALONG THE UPPER-LEVEL FRONT FROM THE
PEORIA AREA WESTWARD. SINCE NO TERMINAL IS IMMEDIATELY THREATENED
BY CONVECTION AT THIS TIME...WILL JUST CARRY VCTS ACROSS THE
BOARD. MODEL SOLUTIONS VARY OVERNIGHT...HOWEVER BOTH THE NAM AND
HRRR STILL SUGGEST A DIMINISHING TREND...WHICH WILL BE FOLLOWED
FOR THIS FORECAST ISSUANCE. WILL THEREFORE END THUNDER MENTION
AFTER 09Z. SCATTERED SHOWERS/THUNDER WILL RE-DEVELOP ON THURSDAY
AS THE FRONT BEGINS TO SLOWLY LIFT BACK NORTHWARD. WILL BRING VCTS
BACK INTO THE FORECAST AT KSPI AND KDEC AFTER 14Z...SPREADING
NORTH TO KPIA BY 20Z. WINDS WILL INITIALLY BE LIGHT/VARIABLE
TONIGHT INTO THURSDAY MORNING...THEN WILL BECOME SOUTHERLY BY
AFTERNOON AND EVENING AS THE FRONT SHIFTS NORTHWARD.

BARNES
&&

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

$$

000
FXUS63 KILX 160443
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1143 PM CDT WED MAY 15 2013

.DISCUSSION...
ISSUED 837 PM CDT WED MAY 15 2013

STATIONARY FRONTAL BOUNDARY BISECTS CENTRAL ILLINOIS THIS
EVENING...WITH COOLER/SLIGHTLY DRIER AIR FILTERING INTO THE FAR
NORTHERN KILX CWA WHERE DEWPOINTS HAVE DROPPED INTO THE UPPER 40S
AND LOWER 50S. FURTHER SOUTH...MOISTURE POOLING ALONG THE BOUNDARY
HAS RESULTED IN DEWPOINTS IN THE LOWER 60S ALONG THE I-72
CORRIDOR. 01Z/8PM IR SATELLITE IMAGERY IS BEGINNING TO SHOW AC
DEVELOPING ALONG THE FRONT...WITH REGIONAL RADAR SHOWING SCATTERED
THUNDERSTORMS DEVELOPING FURTHER WEST ACROSS NORTHERN MISSOURI.
23Z HRRR SUGGESTS CONVECTION WILL DEVELOP EASTWARD ALONG THE
FRONT INTO WEST-CENTRAL ILLINOIS AFTER 03Z/10PM. BASED ON POSITION
OF FRONT AND LATEST HIGH-RES MODEL DATA...HAVE LOWERED POPS TO
JUST SLIGHT CHANCE ACROSS THE SE CWA ALONG/SOUTH OF I-70. FURTHER
NORTH...WENT WITH SCATTERED WORDING ACROSS THE CENTRAL AND
NORTHERN ZONES IN CLOSER PROXIMITY TO THE BOUNDARY. ALSO ADJUSTED
OVERNIGHT LOWS UP A FEW DEGREES...WITH LOWER TO MIDDLE 60S IN MOST
LOCATIONS...EXCEPT COOLER UPPER 50S FAR NORTH. ZONE UPDATE HAS
ALREADY BEEN ISSUED.



&&

.AVIATION...
ISSUED 1142 PM CDT WED MAY 15 2013

STATIONARY FRONTAL BOUNDARY CURRENTLY DRAPED ACROSS THE AREA WILL
BE THE MAIN FOCUSING MECHANISM FOR WIDELY SCATTERED SHOWERS/THUNDER
THROUGH THE ENTIRE 06Z TAF PERIOD. LATEST RADAR IMAGERY SHOWS
SCATTERED CONVECTION IMMEDIATELY AHEAD OF THE FRONT SOUTH OF THE
I-72 CORRIDOR...WITH ANOTHER BROKEN LINE OF SHOWERS/STORMS
DEVELOPING FURTHER NORTH ALONG THE UPPER-LEVEL FRONT FROM THE
PEORIA AREA WESTWARD. SINCE NO TERMINAL IS IMMEDIATELY THREATENED
BY CONVECTION AT THIS TIME...WILL JUST CARRY VCTS ACROSS THE
BOARD. MODEL SOLUTIONS VARY OVERNIGHT...HOWEVER BOTH THE NAM AND
HRRR STILL SUGGEST A DIMINISHING TREND...WHICH WILL BE FOLLOWED
FOR THIS FORECAST ISSUANCE. WILL THEREFORE END THUNDER MENTION
AFTER 09Z. SCATTERED SHOWERS/THUNDER WILL RE-DEVELOP ON THURSDAY
AS THE FRONT BEGINS TO SLOWLY LIFT BACK NORTHWARD. WILL BRING VCTS
BACK INTO THE FORECAST AT KSPI AND KDEC AFTER 14Z...SPREADING
NORTH TO KPIA BY 20Z. WINDS WILL INITIALLY BE LIGHT/VARIABLE
TONIGHT INTO THURSDAY MORNING...THEN WILL BECOME SOUTHERLY BY
AFTERNOON AND EVENING AS THE FRONT SHIFTS NORTHWARD.

BARNES
&&

.PREV DISCUSSION...
ISSUED 259 PM CDT WED MAY 15 2013

FORECAST CONCERN TODAY IS THE POPS ASSOCIATED WITH THE STALLING
FRONT OVER THE REGION INTO THE WEEKEND...AND THEN THE APPROACH OF
THE MAIN UPPER WAVE AND FRONT THE FIRST PART OF NEXT WEEK.

.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT.
MORNING UPPER AIR DATA AND SPC INSTABILITY ANALYSIS SHOWS THE
EAST-WEST FRONTAL ZONE HAD MADE INTO THE NORTH CENTRAL PART OF IL
TODAY...WITH ENOUGH CONVERGENCE ON THE BOUNDARY TO CONTINUE THE
TREND THAT BEGAN OVERNIGHT...OF ELEVATED CONVECTION FORMING AND
MOVING EAST ALONG THE FRONTAL ZONE. THIS TREND HAS BEEN THE CASE
ALL DAY...AS THE UPPER AIR SHOWED A TONGUE OF LOW LEVEL MOISTURE
SURGING NORTH FROM TX OVER MO INTO THE BOUNDARY ZONE. SPC MESODATA
CONTINUED TO SHOW AIR SOUTH OF THE BOUNDARY CAPPED AND THE PCPN
REMAINING ELEVATED. EXPECT THIS TREND TO REMAIN OVERNIGHT...WITH
THE FRONT SAGGING A LITTLE SOUTH.

WITH THE FRONT PROGGED TO BE IN THE REGION BY ALL THE MODELS ON
THURSDAY...WILL KEEP POPS IN THE LIKELY CAT THROUGH CENTRAL REGION.
ADDITIONAL SUPPORT FOR DEVELOPMENT WITH UPPER LEVEL REMAINS OF THE
WEAKENING UPPER WAVE THAT IS OVER TX TODAY. THAT SYSTEM WILL BE
DRIFTING TO THE EAST NORTHEAST OVER OK TO AR. THIS SYSTEM IS
FORECAST TO WASH OUT THURSDAY NIGHT AND THEN THE UPPER RIDGE
BEGINS TO START TO BUILD OVER AREA. LOWERING POPS THEN FRIDAY AND
INTO FRIDAY NIGHT.

.LONG TERM...SATURDAY THROUGH WEDNESDAY.
THE APPROACH OF THE DEEPENING UPPER LOW/WAVE ON SUNDAY GRADUALLY
INCREASES POPS OVER WEST SUNDAY. GFS AND NEW EUR ARE DIFFERENT IN
THE DETAILS ON THE APPROACHING FRONT AND THE UPPER LOW/TROUGH
CONFIGURATION. TODAYS RUN DOES NOT DISPLAY A CLEAR SYSTEM MOVING
THROUGH...BUT A MORE GRADUAL MOVEMENT OF THE UPPER SYSTEM...WHICH
RESULTS IN A LONGER PERIOD OF POPS...FOR SUNDAY INTO THE DAY
WEDNESDAY. WILL STILL HAVE TO WATCH MONDAY FOR SIGNIFICANT
CONVECTION...AS SOUNDING AND HODOGRAPH ON THAT DAY STILL SHOW
POTENTIAL FOR STRONG STORMS.

GOETSCH
&&

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

$$

000
FXUS63 KILX 160137
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
837 PM CDT WED MAY 15 2013

.DISCUSSION...
ISSUED 837 PM CDT WED MAY 15 2013

STATIONARY FRONTAL BOUNDARY BISECTS CENTRAL ILLINOIS THIS
EVENING...WITH COOLER/SLIGHTLY DRIER AIR FILTERING INTO THE FAR
NORTHERN KILX CWA WHERE DEWPOINTS HAVE DROPPED INTO THE UPPER 40S
AND LOWER 50S. FURTHER SOUTH...MOISTURE POOLING ALONG THE BOUNDARY
HAS RESULTED IN DEWPOINTS IN THE LOWER 60S ALONG THE I-72
CORRIDOR. 01Z/8PM IR SATELLITE IMAGERY IS BEGINNING TO SHOW AC
DEVELOPING ALONG THE FRONT...WITH REGIONAL RADAR SHOWING SCATTERED
THUNDERSTORMS DEVELOPING FURTHER WEST ACROSS NORTHERN MISSOURI.
23Z HRRR SUGGESTS CONVECTION WILL DEVELOP EASTWARD ALONG THE
FRONT INTO WEST-CENTRAL ILLINOIS AFTER 03Z/10PM. BASED ON POSITION
OF FRONT AND LATEST HIGH-RES MODEL DATA...HAVE LOWERED POPS TO
JUST SLIGHT CHANCE ACROSS THE SE CWA ALONG/SOUTH OF I-70. FURTHER
NORTH...WENT WITH SCATTERED WORDING ACROSS THE CENTRAL AND
NORTHERN ZONES IN CLOSER PROXIMITY TO THE BOUNDARY. ALSO ADJUSTED
OVERNIGHT LOWS UP A FEW DEGREES...WITH LOWER TO MIDDLE 60S IN MOST
LOCATIONS...EXCEPT COOLER UPPER 50S FAR NORTH. ZONE UPDATE HAS
ALREADY BEEN ISSUED.

BARNES
&&

.AVIATION...
ISSUED 632 PM CDT WED MAY 15 2013

STATIONARY FRONTAL BOUNDARY CURRENTLY DRAPED ACROSS THE AREA WILL
BE THE MAIN FOCUSING MECHANISM FOR WIDELY SCATTERED SHOWERS/THUNDER
THROUGH THE ENTIRE 00Z TAF PERIOD. LATEST RADAR IMAGERY SHOWS VERY
LITTLE PRECIP OCCURRING NOW...ALTHOUGH MOST HIGH-RES MODELS TEND
TO DEVELOP CONVECTION ALONG THE I-72 CORRIDOR AFTER 03Z. WHILE
SOME MODEL SOLUTIONS DIMINISH THIS SCATTERED CONVECTION
OVERNIGHT...OTHERS KEEP IT GOING RIGHT THROUGH THE NIGHT INTO
THURSDAY. DUE TO UNCERTAINTIES CONCERNING EXACT TIMING AND
LOCATION OF ANY CONVECTION...HAVE OPTED TO CARRY ONLY VCTS AT THE
TAF SITES FOR THIS FORECAST ISSUANCE. WILL MENTION THUNDER BETWEEN
03Z AND 08Z AT THE I-72 TERMINALS...WITH DRY CONDITIONS FURTHER
NORTH. AFTER THAT...WILL BRING BACK VCTS AFTER 14Z AS DAYTIME
INSTABILITY RETURNS AND SCATTERED SHOWERS/STORMS DEVELOP IN THE
VICINITY OF THE BOUNDARY. WILL KEEP THUNDER OUT OF THE TAF FOR
BOTH KPIA AND KBMI UNTIL THURSDAY AFTERNOON ONCE FRONT SLOWLY
BEGINS TO RETREAT BACK NORTHWARD. WINDS WILL BE LIGHT/VARIABLE
THROUGHOUT THE PERIOD.

BARNES
&&

.PREV DISCUSSION...
ISSUED 259 PM CDT WED MAY 15 2013

FORECAST CONCERN TODAY IS THE POPS ASSOCIATED WITH THE STALLING
FRONT OVER THE REGION INTO THE WEEKEND...AND THEN THE APPROACH OF
THE MAIN UPPER WAVE AND FRONT THE FIRST PART OF NEXT WEEK.

.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT.
MORNING UPPER AIR DATA AND SPC INSTABILITY ANALYSIS SHOWS THE
EAST-WEST FRONTAL ZONE HAD MADE INTO THE NORTH CENTRAL PART OF IL
TODAY...WITH ENOUGH CONVERGENCE ON THE BOUNDARY TO CONTINUE THE
TREND THAT BEGAN OVERNIGHT...OF ELEVATED CONVECTION FORMING AND
MOVING EAST ALONG THE FRONTAL ZONE. THIS TREND HAS BEEN THE CASE
ALL DAY...AS THE UPPER AIR SHOWED A TONGUE OF LOW LEVEL MOISTURE
SURGING NORTH FROM TX OVER MO INTO THE BOUNDARY ZONE. SPC MESODATA
CONTINUED TO SHOW AIR SOUTH OF THE BOUNDARY CAPPED AND THE PCPN
REMAINING ELEVATED. EXPECT THIS TREND TO REMAIN OVERNIGHT...WITH
THE FRONT SAGGING A LITTLE SOUTH.

WITH THE FRONT PROGGED TO BE IN THE REGION BY ALL THE MODELS ON
THURSDAY...WILL KEEP POPS IN THE LIKELY CAT THROUGH CENTRAL REGION.
ADDITIONAL SUPPORT FOR DEVELOPMENT WITH UPPER LEVEL REMAINS OF THE
WEAKENING UPPER WAVE THAT IS OVER TX TODAY. THAT SYSTEM WILL BE
DRIFTING TO THE EAST NORTHEAST OVER OK TO AR. THIS SYSTEM IS
FORECAST TO WASH OUT THURSDAY NIGHT AND THEN THE UPPER RIDGE
BEGINS TO START TO BUILD OVER AREA. LOWERING POPS THEN FRIDAY AND
INTO FRIDAY NIGHT.

.LONG TERM...SATURDAY THROUGH WEDNESDAY.
THE APPROACH OF THE DEEPENING UPPER LOW/WAVE ON SUNDAY GRADUALLY
INCREASES POPS OVER WEST SUNDAY. GFS AND NEW EUR ARE DIFFERENT IN
THE DETAILS ON THE APPROACHING FRONT AND THE UPPER LOW/TROUGH
CONFIGURATION. TODAYS RUN DOES NOT DISPLAY A CLEAR SYSTEM MOVING
THROUGH...BUT A MORE GRADUAL MOVEMENT OF THE UPPER SYSTEM...WHICH
RESULTS IN A LONGER PERIOD OF POPS...FOR SUNDAY INTO THE DAY
WEDNESDAY. WILL STILL HAVE TO WATCH MONDAY FOR SIGNIFICANT
CONVECTION...AS SOUNDING AND HODOGRAPH ON THAT DAY STILL SHOW
POTENTIAL FOR STRONG STORMS.

GOETSCH
&&

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

$$

000
FXUS63 KILX 152332
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
632 PM CDT WED MAY 15 2013

.DISCUSSION...
ISSUED 259 PM CDT WED MAY 15 2013

FORECAST CONCERN TODAY IS THE POPS ASSOCIATED WITH THE STALLING
FRONT OVER THE REGION INTO THE WEEKEND...AND THEN THE APPROACH OF
THE MAIN UPPER WAVE AND FRONT THE FIRST PART OF NEXT WEEK.

.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT.
MORNING UPPER AIR DATA AND SPC INSTABILITY ANALYSIS SHOWS THE
EAST-WEST FRONTAL ZONE HAD MADE INTO THE NORTH CENTRAL PART OF IL
TODAY...WITH ENOUGH CONVERGENCE ON THE BOUNDARY TO CONTINUE THE
TREND THAT BEGAN OVERNIGHT...OF ELEVATED CONVECTION FORMING AND
MOVING EAST ALONG THE FRONTAL ZONE. THIS TREND HAS BEEN THE CASE
ALL DAY...AS THE UPPER AIR SHOWED A TONGUE OF LOW LEVEL MOISTURE
SURGING NORTH FROM TX OVER MO INTO THE BOUNDARY ZONE. SPC MESODATA
CONTINUED TO SHOW AIR SOUTH OF THE BOUNDARY CAPPED AND THE PCPN
REMAINING ELEVATED. EXPECT THIS TREND TO REMAIN OVERNIGHT...WITH
THE FRONT SAGGING A LITTLE SOUTH.

WITH THE FRONT PROGGED TO BE IN THE REGION BY ALL THE MODELS ON
THURSDAY...WILL KEEP POPS IN THE LIKELY CAT THROUGH CENTRAL REGION.
ADDITIONAL SUPPORT FOR DEVELOPMENT WITH UPPER LEVEL REMAINS OF THE
WEAKENING UPPER WAVE THAT IS OVER TX TODAY. THAT SYSTEM WILL BE
DRIFTING TO THE EAST NORTHEAST OVER OK TO AR. THIS SYSTEM IS
FORECAST TO WASH OUT THURSDAY NIGHT AND THEN THE UPPER RIDGE
BEGINS TO START TO BUILD OVER AREA. LOWERING POPS THEN FRIDAY AND
INTO FRIDAY NIGHT.

.LONG TERM...SATURDAY THROUGH WEDNESDAY.
THE APPROACH OF THE DEEPENING UPPER LOW/WAVE ON SUNDAY GRADUALLY
INCREASES POPS OVER WEST SUNDAY. GFS AND NEW EUR ARE DIFFERENT IN
THE DETAILS ON THE APPROACHING FRONT AND THE UPPER LOW/TROUGH
CONFIGURATION. TODAYS RUN DOES NOT DISPLAY A CLEAR SYSTEM MOVING
THROUGH...BUT A MORE GRADUAL MOVEMENT OF THE UPPER SYSTEM...WHICH
RESULTS IN A LONGER PERIOD OF POPS...FOR SUNDAY INTO THE DAY
WEDNESDAY. WILL STILL HAVE TO WATCH MONDAY FOR SIGNIFICANT
CONVECTION...AS SOUNDING AND HODOGRAPH ON THAT DAY STILL SHOW
POTENTIAL FOR STRONG STORMS.

GOETSCH
&&

.AVIATION...
ISSUED 632 PM CDT WED MAY 15 2013

STATIONARY FRONTAL BOUNDARY CURRENTLY DRAPED ACROSS THE AREA WILL
BE THE MAIN FOCUSING MECHANISM FOR WIDELY SCATTERED SHOWERS/THUNDER
THROUGH THE ENTIRE 00Z TAF PERIOD. LATEST RADAR IMAGERY SHOWS VERY
LITTLE PRECIP OCCURRING NOW...ALTHOUGH MOST HIGH-RES MODELS TEND
TO DEVELOP CONVECTION ALONG THE I-72 CORRIDOR AFTER 03Z. WHILE
SOME MODEL SOLUTIONS DIMINISH THIS SCATTERED CONVECTION
OVERNIGHT...OTHERS KEEP IT GOING RIGHT THROUGH THE NIGHT INTO
THURSDAY. DUE TO UNCERTAINTIES CONCERNING EXACT TIMING AND
LOCATION OF ANY CONVECTION...HAVE OPTED TO CARRY ONLY VCTS AT THE
TAF SITES FOR THIS FORECAST ISSUANCE. WILL MENTION THUNDER BETWEEN
03Z AND 08Z AT THE I-72 TERMINALS...WITH DRY CONDITIONS FURTHER
NORTH. AFTER THAT...WILL BRING BACK VCTS AFTER 14Z AS DAYTIME
INSTABILITY RETURNS AND SCATTERED SHOWERS/STORMS DEVELOP IN THE
VICINITY OF THE BOUNDARY. WILL KEEP THUNDER OUT OF THE TAF FOR
BOTH KPIA AND KBMI UNTIL THURSDAY AFTERNOON ONCE FRONT SLOWLY
BEGINS TO RETREAT BACK NORTHWARD. WINDS WILL BE LIGHT/VARIABLE
THROUGHOUT THE PERIOD.

BARNES
&&

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

$$

000
FXUS63 KILX 152003
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
303 PM CDT WED MAY 15 2013

.DISCUSSION...
ISSUED 259 PM CDT WED MAY 15 2013

FORECAST CONCERN TODAY IS THE POPS ASSOCATED WITH THE STALLING
FRONT OVER THE REGION INTO THE WEEKEND...AND THEN THE APPROACH OF
THE MAIN UPPER WAVE AND FRONT THE FIRST PART OF NEXT WEEK.

.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT.
MORNING UPPER AIR DATA AND SPC INSTABILITY ANALYSIS SHOWS THE
EAST-WEST FRONTAL ZONE HAD MADE INTO THE NORTH CENTRAL PART OF IL
TODAY...WITH ENOUGH CONVERGENCE ON THE BOUNDARY TO CONTINUE THE
TREND THAT BEGAN OVERNIGHT...OF ELEVATED CONVECTION FORMING AND
MOVING EAST ALONG THE FRONTAL ZONE. THIS TREND HAS BEEN THE CASE
ALL DAY...AS THE UPPER AIR SHOWED A TONGUE OF LOW LEVEL MOISTURE
SURGING NORTH FROM TX OVER MO INTO THE BOUNDARY ZONE. SPC MESODATA
CONTINUED TO SHOW AIR SOUTH OF THE BOUNDARY CAPPED AND THE PCPN
REMAINING ELEVATED. EXPECT THIS TREND TO REMAIN OVERNIGHT...WITH
THE FRONT SAGGING A LITTLE SOUTH.

WITH THE FRONT PROGGED TO BE IN THE REGION BY ALL THE MODELS ON
THURSDAY...WILL KEEP POPS IN THE LIKELY CAT THROUGH CENTRAL REGION.
ADDITIONAL SUPPORT FOR DEVELOPMENT WITH UPPER LEVEL REMAINS OF THE
WEAKENING UPPER WAVE THAT IS OVER TX TODAY. THAT SYSTEM WILL BE
DRIFTING TO THE EAST NORTHEAST OVER OK TO AR. THIS SYSTEM IS
FORECAST TO WASH OUT THURSDAY NIGHT AND THEN THE UPPER RIDGE
BEGINS TO START TO BUILD OVER AREA. LOWERING POPS THEN FRIDAY AND
INTO FRIDAY NIGHT.

.LONG TERM...SATURDAY THROUGH WEDNESDAY.
THE APPROACH OF THE DEEPENDING UPPER LOW/WAVE ON SUNDAY GRADUALLY
INCREASES POPS OVER WEST SUNDAY. GFS AND NEW EUR ARE DIFFERENT IN
THE DETAILS ON THE APPROACHING FRONT AND THE UPPER LOW/TROUGH
CONFIGURATION. TODAYS RUN DOES NOT DISPLAY A CLEAR SYSTEM MOVING
THROUGH...BUT A MORE GRADUAL MOVEMENT OF THE UPPER SYSTEM...WHICH
RESULTS IN A LONGER PERIOD OF POPS...FOR SUNDAY INTO THE DAY
WEDNESDAY. WILL STILL HAVE TO WATCH MONDAY FOR SIGNIFICANT
CONVECTION...AS SOUNDING AND HODOGRAPH ON THAT DAY STILL SHOW
POTENTIAL FOR STRONG STORMS.

GOETSCH
&&

.AVIATION...
ISSUED 1219 PM CDT WED MAY 15 2013

SHOWERS AND ISOLATED THUNDERSTORMS INCREASING ALONG A FRONTAL
BOUNDARY...WHICH EXTENDS FROM KMQB TO JUST SOUTH OF KIKK AT 17Z.
COVERAGE IS SCATTERED...AND WILL ADDRESS IT WITH VCTS INITIALLY AT
KPIA/KBMI...THEN FURTHER SOUTH MID TO LATE AFTERNOON AS THE
BOUNDARY SLOWLY SINKS. MOST 12Z MODEL GUIDANCE IN AGREEMENT WITH
STALLING THIS BOUNDARY OVER CENTRAL ILLINOIS THIS EVENING...WITH A
NORTHWARD PUSH BEGINNING ON THURSDAY MORNING. SHOWERS/STORMS WILL
REMAIN SCATTERED WITH THIS BOUNDARY AROUND...WITH THE 06-12Z TIME
FRAME MOST LIKELY TO SEE THE BETTER CHANCES OF DRY WEATHER. ENOUGH
CONFIDENCE EXISTS FOR A TEMPO MENTION OF TSRA FROM ABOUT 03-07Z
FROM KSPI EAST TO KCMI.

GEELHART
&&

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

$$

000
FXUS63 KILX 151720
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1220 PM CDT WED MAY 15 2013

.DISCUSSION...
ISSUED 1000 AM CDT WED MAY 15 2013

FRONTAL BOUNDARY IS SLOWLY SLIPPING SOUTHWARD ACROSS ILLINOIS...
AND WAS ROUGHLY ALONG A GALESBURG TO KANKAKEE JUST BEFORE 10 AM.
HAVE BEEN SEEING A PERSISTENT BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS...WHICH HAD MAINLY BEEN MOVING EASTWARD ACROSS THE
EXTREME NORTHERN CWA. THIS HAS STARTED SHOWING A BIT OF A
SOUTHWARD PUSH INTO AN AREA WITH A STRONGER CAP...SO AM NOT
EXPECTING IT TO GO MUCH FURTHER SOUTH THIS MORNING. LATEST RAP
MODEL SHOWING THE MORE SIGNIFICANT CAP EROSION HOLDING OFF UNTIL
LATER THIS AFTERNOON...SO HAVE ADJUSTED AFTERNOON POPS TO REFLECT
THE HIGHEST CHANCES AFTER 3 PM. ALSO MADE ADJUSTMENTS TO THE
WINDS...WITH GUSTS OF 20-30 MPH THIS MORNING EXPECTED TO SETTLE
DOWN SOME THIS AFTERNOON.

GEELHART


&&

.AVIATION...
ISSUED 1219 PM CDT WED MAY 15 2013

SHOWERS AND ISOLATED THUNDERSTORMS INCREASING ALONG A FRONTAL
BOUNDARY...WHICH EXTENDS FROM KMQB TO JUST SOUTH OF KIKK AT 17Z.
COVERAGE IS SCATTERED...AND WILL ADDRESS IT WITH VCTS INITIALLY AT
KPIA/KBMI...THEN FURTHER SOUTH MID TO LATE AFTERNOON AS THE
BOUNDARY SLOWLY SINKS. MOST 12Z MODEL GUIDANCE IN AGREEMENT WITH
STALLING THIS BOUNDARY OVER CENTRAL ILLINOIS THIS EVENING...WITH A
NORTHWARD PUSH BEGINNING ON THURSDAY MORNING. SHOWERS/STORMS WILL
REMAIN SCATTERED WITH THIS BOUNDARY AROUND...WITH THE 06-12Z TIME
FRAME MOST LIKELY TO SEE THE BETTER CHANCES OF DRY WEATHER. ENOUGH
CONFIDENCE EXISTS FOR A TEMPO MENTION OF TSRA FROM ABOUT 03-07Z
FROM KSPI EAST TO KCMI.

GEELHART

&&

.PREV DISCUSSION...
ISSUED 326 AM CDT WED MAY 15 2013

SHORT TERM...TODAY THROUGH FRIDAY

COLD FRONT AT 07Z EXTENDED FROM SOUTHWEST WI BACK THROUGH CENTRAL
IA. THIN LINE OF CONVECTION TRYING TO FIRE ALONG A PRE-FRONTAL
TROF NEAR THE I-80 CORRIDOR CURRENTLY. HI-RES SHORT RANGE MODELS
KEEP THIS ACTIVITY NORTH OF THE CWA THROUGH MID MORNING. PRE-FRONTAL
AIRMASS REMAINS QUITE WARM WITH SW WINDS GUSTING OVER 20 MPH AND
MANY LOCATIONS STILL IN THE MID 70S EARLY THIS MORNING. MAIN
FEATURE OF INTEREST TODAY IS THE FRONT WHICH SINKS SOUTH TO NEAR
THE I-72 CORRIDOR THIS EVENING BEFORE STALLING OUT. NOT MUCH FOCUS
FOR ACTIVITY ALONG THE FRONT FOR THE BULK OF THE DAY AS FORCING
AND CONVERGENCE ARE WEAK. FORECAST SOUNDING ALSO SHOW SIGNIFICANT
CAPPING IN PLACE AS WELL AND HAVE LOWERED POPS TO SLGT/LOW CHANCE.
HIGHS REMAIN WELL ABOVE NORMAL AND WITHOUT MUCH OF A COOL PUNCH
BEHIND THE FRONT EVEN THE NORTHERN CWA SHOULD GET INTO THE LOWER
80S...WHILE UPPER 80S POSSIBLE FOR THE SOUTH. BY LATE AFTERNOON
AND ESPECIALLY AFTER 00Z AREA COMES UNDER BETTER MOISTURE
ADVECTION AS A SOUTHERN STREAM MID LEVEL TROF LIFTS NORTHEAST
TOWARDS THE MID MISSISSIPPI VALLEY. THIS IN CONJUNCTION WITH MID
LEVEL COOLING ERODES CAPPING AND SHOULD ALLOW SCATTERED CONVECTION
TO DEVELOP IN THE VICINITY OF THE BOUNDARY. MODEL DEWPOINTS AROUND
70F APPEAR SEVERAL DEGREES TOO HIGH AND LEAD TO CAPES IN EXCESS OF
3K J/KG. WITH EXPECTED LOW 60S DEWPOINT POOL...CAPES ON THE ORDER
OF 1500 SEEM REASONABLE. WINDS ALOFT ARE WEAK UNDER 25 KTS SO
SHOULDNT BE MUCH STORM ORGANIZATION...BUT WITH THAT INSTABILITY
GUSTY WINDS AND HEAVY DOWNPOURS POSSIBLE ESPECIALLY IF STORMS CAN
GET GOING BEFORE DIURNAL HEATING WANES.

LITTLE CHANGE IN THE PATTERN THROUGH THURSDAY...AS THE QUASI-
STATIONARY FRONT WAVERS OVER THE CWA AND THE WEAKENING TROF LIFTS
THROUGH. SO WILL MAINTAIN HIGH CHANCE TO LIKELY POPS THROUGH
THURSDAY. BY THURSDAY NIGHT THE FRONT FINALLY BEGINS TO LIFT BACK
NORTH AND COULD PUSH INTO NORTHERN IL BY FRIDAY MORNING. BUT TO
KEEP THE POPS PARADE GOING...YET ANOTHER LOW AMPLITUDE MID LEVEL
WAVE SHIFTS INTO MO ON FRIDAY. ASSOCIATED LIFT AND MOISTURE AHEAD
OF THIS FEATURE SHOULD BRING ADDITIONAL CONVECTION TO THE CWA.
SLOW MOVEMENT OF THIS WAVE KEEPS PRECIP CHANCES GOING FRIDAY
NIGHT.

LONG TERM...SATURDAY THROUGH TUESDAY

WEAK MID LEVEL FLOW CAUSES THE TROF TO NEARLY STALL OVER THE LOWER
OHIO VALLEY REGION ON SATURDAY AND THIS WILL LEAD TO A CONTINUED
CHANCE OF SHOWERS/STORMS WITH HIGHEST COVERAGE OVER THE EASTERN
CWA. FINALLY BY SATURDAY NIGHT THIS SYSTEM SHIFTS EAST AND A BRIEF
PERIOD OF UPPER RIDGING BUILDS OVER IL AND WE HAVE A PERIOD
WITHOUT MENTION OF PRECIP. ATTENTION FOR THE LAST HALF OF THE
WEEKEND TURNS TO A MORE SIGNIFICANT TROF DEVELOPING OVER THE
PLAINS. EXTENDED MODELS OFFER DIFFERENT SOLUTIONS OF THE STRENGTH
OF THIS TROF WHICH AFFECTS HOW QUICKLY THE ASSOCIATED COLD FRONT
BRINGS THE NEXT CHANCE OF STORMS TO THE AREA. ECMWF MOST
PROGRESSIVE AND WOULD BRING ACTIVITY IN LATE SUNDAY...WHILE OTHER
GUIDANCE SHOWS THIS HOLDING OFF UNTIL MONDAY. WHILE MANY DETAILS
NEED TO BE WORKED OUT...STRENGTH OF UPPER JET AND INSTABILITY
SUGGEST STRONG OR SEVERE STORMS POSSIBLE FOR THE LOCAL AREA. WILL
NEED TO MAINTAIN HIGH CHANCE POPS SUNDAY NIGHT THROUGH MONDAY
NIGHT TO ACCOUNT FOR TIMING UNCERTAINTY. SLOW MOVEMENT OF UPPER
TROF MAY LEAD TO MORE STORM DEVELOPMENT ON TUESDAY MAINLY OVER THE
EASTERN CWA UNTIL A COLD FRONT FINALLY PUSHES EAST BY AFTERNOON
ACCORDING TO LATEST ECMWF. TEMPS WILL REMAIN WELL ABOVE NORMAL
UNTIL COOLER AIR ASSOCIATED WITH THE TROF MOVES IN FOR LATER
TUESDAY INTO MID-WEEK.

25


&&

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

$$