FXUS63 KILX 010527
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1127 PM CST MON NOV 30 2009

.DISCUSSION...
ISSUED 737 PM CST MON NOV 30 2009

HIGH PRESSURE DOMINATES THE WEATHER ACROSS CENTRAL ILLINOIS THIS
EVENING...RESULTING IN CLEAR SKIES AND RAPIDLY COOLING TEMPS.
DESPITE SOUTHWESTERLY RETURN FLOW ON THE BACK SIDE OF THE
HIGH...TEMPS HAVE STEADILY DROPPED OVER THE PAST COUPLE OF HOURS
TO CURRENT READINGS MAINLY IN THE MIDDLE TO UPPER 30S. THE COOLEST
TEMPS IN THE LOWER 30S ARE FOCUSED IN THE WABASH RIVER
VALLEY...WHERE RETURN FLOW IS LIGHTEST. HAVE ADJUSTED OVERNIGHT LOWS
TO DROP READINGS INTO THE UPPER 20S ALONG AND EAST OF I-57...WITH
LOWER 30S ELSEWHERE. CHANGES ARE MINOR ENOUGH THAT A FULL ZONE
UPDATE IS NOT WARRANTED AT THIS TIME.

&&

.AVIATION...
ISSUED 1127 PM CST MON NOV 30 2009

VFR CONDITIONS WILL PREVAIL THROUGH THE ENTIRE 06Z TAF PERIOD...AS
HIGH PRESSURE REMAINS IN CONTROL OF THE WEATHER. SOUTHWESTERLY
WINDS OF AROUND 10KT TONIGHT WILL INCREASE INTO THE 10 TO 15KT
RANGE WITH GUSTS UP TO 22KT ON TUESDAY. GUSTS WILL SUBSIDE BY
23Z...WITH SUSTAINED WINDS OF 10 TO 15KT CONTINUING THROUGH 06Z.
SKIES WILL BE CLEAR THROUGH TUESDAY AFTERNOON...BEFORE HIGH
CLOUDINESS BEGINS TO INCREASE AHEAD OF THE NEXT APPROACHING
WEATHER SYSTEM.

BARNES
&&

.PREV DISCUSSION...
ISSUED 130 PM CST MON NOV 30 2009

SURFACE HIGH PRESSURE ACRS WRN OK WITH A RIDGE AXIS NE THRU CNTRL
IL BRINGING PLEASANT WEATHER CONDITIONS TO MOST OF THE FORECAST
AREA EARLY THIS AFTN. CLOUDS CONTINUE TO ERODE QUICKLY ACRS ERN
IL AND EXPECT THAT TREND TO CONTINUE...WHILE FURTHER TO OUR NW...
A WEAK SFC TROF/WIND SHIFT LINE RESPONSIBLE FOR SOME CLOUDS AND
FLURRIES OVR NRN MN AND WISCONSIN. 

THE MAIN FORECAST CONCERN WL CONTINUE TO BE WITH THE STORM SYSTEM
EXPECTED TO PUSH TWDS THE AREA WEDNESDAY/WEDNESDAY NIGHT...BRINGING
THE POTENTIAL FOR SOME MEASUREABLE SNOW WEDNESDAY NIGHT...ESPECIALLY
EAST OF INTERSTATE 55. LONGER RANGE STILL LOOKS COLD WITH A DEEP
TROF JUST SOUTH OF HUDSON BAY FCST TO ONLY SLOWLY PULL AWAY FROM 
THE GREAT LAKES LATE NEXT WEEKEND. 

SHORT TERM...TONIGHT THROUGH THURSDAY 

NOT SEEING A GREAT DEAL OF MODEL DIFFERENCES EARLY ON IN THIS
PERIOD WITH THE HIGH TO OUR SOUTHWEST FORECAST TO DRIFT WELL SOUTH
OF OUR AREA TNT. SYSTEM TO OUR NORTH SHOULD PUSH WELL TO OUR NORTH
AND EAST OVERNIGHT WITH A SCATTERING OF SOME MID AND HIGH CLOUDS
POSSIBLE ACRS THE NRN PORTION OF THE FCST AREA. TRENDING AT OR BELOW
GUID SE...AND A MAV/MET BLEND TO THE NW.  

ON TUESDAY...MODELS INDICATE A NRN STREAM SHORTWAVE TO DIG SOUTHEAST
PLAINS ON TUESDAY BRINGING A COLD FRONT SE INTO WRN IOWA BY WED
AFTN. ALTHOUGH NOT AS AGRESSIVE AS YSTDY...MODELS CONTINUE TO
INDICATE A DECENT 850 MB WARM AXIS JUST AHEAD OF THE BOUNDARY
TOMORROW AFTN...AND COUPLED WITH A LOW LEVEL SOUTHWEST FLOW AND
COPIOUS AMTS OF SUNSHINE...AFTN TEMPS SHOULD PUSH WELL INTO THE
50S...WITH LOW 60S POSSIBLE ACRS THE SOUTHWEST.

MODELS TRENDING A BIT FURTHER NORTHWEST WITH THE WED/WED NIGHT SYSTEM
WITH THE CANADIAN GEM AND TO SOME EXTENT THE EURO MODEL MORE
CONSISTENT WITH THIS SYSTEM. FORECAST SOUNDINGS SUGGEST PRECIP WL
START OUT AS RAIN WEDNESDAY AND THEN GO TO A MIX OF RAIN AND SNOW
LATE IN THE AFTN ACRS THE SOUTHWEST WITH STRONG FRONTOGENETICAL
FORCING AND EVAP COOLING TO THE NORTHWEST OF THE TRACK OF THE SFC
LOW INDICATING A FAIRLY QUICK CHANGE TO SNOW WED EVENING. BASED ON
THE CURRENT TRACK OF THE SFC LOW AND ASSOCIATED CLOSED 850 MB 
LOW...CHANCES FOR SEEING ACCUMULATING SNOWS INCREASE EAST OF I-55.
COULD SEE AN INCH OR TWO OF WET SNOW BY LATE WED NIGHT INTO THU 
MRNG.

ONCE THE STORM SHIFTS QUICKLY TO OUR NORTHEAST THURS MORNING...THE
FLOOD GATES OPEN WITH RESPECT TO THE COLD AIR PUSHING IN BEHIND
THE STORM SYSTEM ON THURSDAY. A GUSTY NORTHWEST WIND COUPLED WITH
SCATTERED SNOW SHOWERS AND FLURRIES WL MAKE FOR A WINTRY DAY ACRS
CENTRAL AND SOUTHEAST IL WITH AFTN TEMPS THURSDAY STRUGGLING TO
GET OUT OF THE 30S.

LONG TERM...FRIDAY THROUGH MONDAY

THE UPPER FLOW PATTERN ACRS THE LOWER 48 THIS PERIOD WILL SUPPORT
THE COLDEST AIR OF THE SEASON SO FAR THRU NEXT WEEKEND AS A DEEP
UPPER LOW REMAINS NEAR HUDSON BAY. HAVE INCLUDED FLURRIES ON
FRIDAY AS THE BROAD LOW LEVEL CYCLONIC FLOW CONTINUES ACRS THE
REGION WITH MOSTLY DRY WEATHER EXPECTED INTO EARLY NEXT WEEK.
DAYTIME HIGHS ON FRIDAY IN THE HEART OF THE COLD AIR MASS WILL
STRUGGLE THRU THE UPPER 20S NORTH AND CENTRAL...TO THE LOWER 30S
SE WITH EARLY MRNG LOWS FRIDAY AND SATURDAY IN THE TEENS.

ENSEMBLES AGREE ON THE IDEA OF THE UPPER LOW BEGINNING TO PUSH
FURTHER TO OUR NORTHEAST BY LATE SUNDAY OR MONDAY OF NEXT
WEEK...WHICH SHOULD ALLOW A GRADUAL MODERATING TREND TO WORK BACK
INTO THE MIDWEST. TEMPERATURES UNTIL THEN WILL AVERAGE WELL BELOW
NORMAL.

SMITH

&&

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

$$