000
FXUS63 KILX 241714
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1214 PM CDT FRI MAY 24 2013

.DISCUSSION...
ISSUED 953 AM CDT FRI MAY 24 2013

HIGH PRESSURE CENTERED OVER WISCONSIN THIS MORNING...WITH RIDGING
EXTENDING SOUTHWARD INTO THE LOWER MISSISSIPPI VALLEY. SKIES
EXPECTED TO REMAIN PRETTY CLEAR AS DRY AIR REMAINS PROMINENT
ALOFT. MADE ONLY MINOR TWEAKS TO THE GRIDS...MAINLY WITH THE WINDS
AND DEW POINTS. HAVE RESENT THE ZONES AS WELL...AS THERE WERE A
COUPLE MINOR ADJUSTMENTS THAT RESULTED FROM THE GRID TWEAKS.

GEELHART


&&

.AVIATION...
ISSUED 1214 PM CDT FRI MAY 24 2013

LITTLE CONCERN AVIATION-WISE THROUGH 06Z AS NORTHEAST WINDS
GRADUALLY SHIFT EASTERLY WITH HIGH PRESSURE PASSING TO THE NORTH.
OVERNIGHT...A THUNDERSTORM COMPLEX WILL DEVELOP OVER IOWA AND
MOVE SOUTHEAST. LATEST MODEL GUIDANCE HINTS AT SOME OF THE
REMNANTS PASSING NEAR KPIA/KBMI LATE SATURDAY MORNING...WITH THE
BETTER CHANCES JUST TO THE NORTH. OTHERWISE...CEILINGS LATE IN THE
PERIOD SHOULD REMAIN ABOVE 10KFT.

GEELHART

&&

.PREV DISCUSSION...
ISSUED 330 AM CDT FRI MAY 24 2013

00Z SHORT RANGE MODELS ARE IN FAIR AGREEMENT NEXT FEW DAYS AS
BELOW NORMAL TEMPS PREVAIL THROUGH SUNDAY AND THEN WARM UP DURING
NEXT WEEK. DRY CONDITIONS EXPECTED ACROSS AREA THROUGH THIS
EVENING THEN MODELS DIFFER WITH QPF FIELDS DURING THIS HOLIDAY
WEEKEND AND HAVE TRENDED HIGHER WITH POPS WESTERN/SW AREAS AND
LOWER WITH POPS EASTERN/NE AREAS. SO TRENDED FORECAST IN THAT
DIRECTION.

SHORT TERM...TODAY THROUGH SUNDAY NIGHT

1030 MB CANADIAN HIGH PRESSURE OVER THE NORTH WOODS OF NORTHERN WI
AND WESTERN UPPER MI AND RIDGING SOUTHWARD THROUGH ILLINOIS BRINGING
CLEAR SKIES AND NORTH WINDS GENERALLY LESS THAN 10 MPH. COOL TEMPS
WERE IN THE LOW TO MID 40S AND WILL SLIP A FEW MORE DEGREES WITH
SOME UPPER 30S BY DAWN FROM BLOOMINGTON AND DECATUR AND MATTOON EAST.
FROST APPEARS TO BE CONFINED TO AREAS NE OF CENTRAL IL EARLY THIS
MORNING WITH LAFAYETTE INDIANA CURRENTLY AT 37F. AMPLE SUNSHINE
EXPECTED TODAY WITH NE WINDS 5 TO 10 MPH WITH HIGH PRESSURE RIDGE
OVERHEAD WITH HIGHS IN THE MIDDLE TO UPPER 60S AND COOLEST OVER EAST
CENTRAL IL.

SURFACE RIDGE MOVES SLOWLY OVER LAKE MI BY DAWN SAT AND TO KEEP
MOST OF CENTRAL/SE IL DRY MUCH OF TONIGHT. STILL THINK A 20-40%
CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS TO AFFECT AREAS NW OF
I-55 LATER TONIGHT WITH BEST CHANCES NW OF THE IL RIVER. THIS DUE
TO SHORT WAVE RIDGING OVER TOP OF UPPER LEVEL RIDGE AND TRACK SE
FROM IA TOWARD NW IL BY DAWN SAT. DISTURBANCE WILL NEED TO
OVERCOME DRY AIR IN PLACE OVER CENTRAL IL.

00Z NAM MODEL APPEARS TOO FAR NE INTO DRY AIR WITH WARM AIR
ADVECTION QPF BAND INTO NE IL SAT AND SAT NIGHT AND LEANED ON
FURTHER SW MODELS OF 00Z ECMWF...GEM AND GFS IN HAVING HIGHEST
POPS WESTERN AND SW AREAS THIS WEEKEND AND LOWER POPS OVER EASTERN
AND NE AREAS ESPECIALLY NEAR THE INDIANA BORDER. HAVE GOOD CHANCE
OF SHOWERS AND THUNDERSTORMS SPREADING ACROSS AREA SUNDAY NIGHT
AND MONDAY. HIGHS IN THE MID TO UPPER 60S SAT WITH FAR SE AROUND
70F TO MODIFY TO MID TO UPPER 70S BY MONDAY.

LONG TERM...MONDAY THROUGH FRIDAY

EXTENDED MODELS/ENSEMBLES ARE IN FAIR AGREEMENT WITH THE UPPER
LEVEL PATTERN OVER THE MIDWEST DURING NEXT WEEK. UPPER LEVEL RIDGE
OVER THE GREAT PLAINS WILL MOVE EAST INTO IL AND OHIO VALLEY BY
THE MIDDLE OF NEXT WEEK. SHORT WAVE TROUGHS TO RIDE THROUGH THE
RIDGE ON MONDAY AND TUESDAY AND WILL CONTINUE A CHANCE OF SHOWERS
AND THUNDERSTORMS ACROSS CENTRAL AND SE IL EARLY NEXT WEEK. BY
NEXT WEDNESDAY AND THURSDAY...UPPER LEVEL RIDGE WILL BUILD
NORTHWARD OVER THE REGION DUE TO STRONG TROUGHING OVER THE WEST
COAST AND ROCKIES. THIS WILL SHIFT BEST CHANCE OF SHOWERS AND
THUNDERSTORMS NORTH OF CENTRAL IL DURING WED/THU AS SUMMER-LIKE
TEMPS AND HUMIDITY LEVELS RETURN TO CENTRAL AND SE IL. MAINLY
CARRIED SMALL POPS OVER NORTHERN AREAS ESPECIALLY THE IL RIVER
VALLEY.

07


&&

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

$$