794 
FXUS63 KILX 040851
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
251 AM CST FRI JAN 4 2013

.DISCUSSION...
ISSUED 251 AM CST FRI JAN 4 2013

MAIN CHALLENGE IN THE SHORT-TERM WILL BE PRECIP CHANCES IN
ADVANCE OF A WAVE LIFTING NORTHEASTWARD THROUGH THE REGION ON
SATURDAY. FURTHER OUT...EMPHASIS SHIFTS TO TIMING OF A MORE
SIGNIFICANT STORM SYSTEM NEXT WEEK.

SHORT TERM...TODAY THROUGH SUNDAY

HIGH PRESSURE WILL BRING SUNNY SKIES AND SEASONABLE TEMPERATURES
IN THE LOWER TO MIDDLE 30S TODAY. AS THE HIGH SHIFTS OFF TO THE
EAST...SOUTHWESTERLY RETURN FLOW TONIGHT WILL KEEP TEMPERATURES A
BIT WARMER THAN THEY HAVE BEEN IN RECENT NIGHTS...WITH LOWS IN THE
UPPER TEENS AND LOWER 20S. SKIES WILL REMAIN CLEAR THROUGH MUCH OF
THE NIGHT...WITH AN INCREASE IN HIGH CLOUDS NOTED ACROSS THE W/SW
KILX CWA TOWARD DAWN.

UPPER LOW CURRENTLY SPINNING OVER WEST TEXAS WILL GET SHUNTED
NORTHEASTWARD AHEAD OF AN APPROACHING NORTHERN STREAM SHORT-WAVE
TROUGH ON SATURDAY. MODELS HAVE BEEN TRENDING WETTER WITH THIS
FEATURE FOR THE PAST SEVERAL RUNS...AND THE 00Z 4 JAN SUITE IS NO
EXCEPTION. NAM/GFS/ECMWF ALL DEVELOP LIGHT PRECIP IN ADVANCE OF THE
WAVE ALONG/AHEAD OF AN APPROACHING COLD FRONT SATURDAY AFTERNOON.
DESPITE OVERALL WEAKENING TREND ALOFT...ENOUGH SYNOPTIC LIFT WILL
BE GENERATED TO WARRANT LOW CHANCE POPS. FORECAST SOUNDINGS AND
TIME-HEIGHT CROSS-SECTIONS SUGGEST A DEEP ENOUGH MOISTURE PROFILE
WILL EXIST TO SUPPORT THE POTENTIAL FOR MEASURABLE PRECIP. THINK
HIGHEST POPS AND GREATEST QPF WILL BE FOCUSED ACROSS THE W/NW 
CWA...WHERE APPROACHING COLD FRONT WILL PROVIDE ADDITIONAL LIFT.
THERMAL PROFILE FAVORS SNOW...HOWEVER SURFACE TEMPERATURES IN THE
MIDDLE TO UPPER 30S ACROSS THE SOUTHEAST MAY LEAD TO A RAIN/SNOW
MIX SOUTH OF I-70. ANY ACCUMULATIONS WILL BE MINOR...AS SNOW WILL
BE LIGHT AND WARM SURFACE TEMPS WILL CAUSE MELTING. AT THIS
POINT...IT APPEARS ONE HALF INCH OR LESS OF SLUSHY WET SNOW WILL
FALL ALONG AND NORTHWEST OF A DANVILLE TO TAYLORVILLE LINE...WITH
LITTLE OR NO ACCUMULATION FURTHER SOUTHEAST.

PRECIP CHANCES WILL QUICKLY TAPER OFF SATURDAY EVENING...AS BEST
LIFT SHIFTS FURTHER E/NE. WITH NORTHERN-STREAM WAVE STILL TO THE
WEST...HAVE MAINTAINED CHANCE FOR FLURRIES THROUGH SATURDAY NIGHT.
WILL HAVE TO MONITOR FUTURE MODEL RUNS...AS FORECAST SOUNDINGS
SUGGEST A LOSS OF ICE CRYSTALS MAY MEAN ANY LINGERING LIGHT PRECIP
MAY ACTUALLY BE IN THE FORM OF FREEZING DRIZZLE. WILL LEAVE OUT OF
THE FORECAST FOR NOW...PENDING SUPPORT FROM ADDITIONAL MODEL RUNS.
ONCE THE NORTHERN WAVE EXITS THE REGION...COOL/DRY WEATHER WILL
PREVAIL ON SUNDAY.

LONG TERM...MONDAY THROUGH THURSDAY

WARMER WEATHER IS STILL ON TAP FOR NEXT WEEK...HOWEVER TIMING OF
NEXT STORM SYSTEM IS NOW IN QUESTION. MODEL SOLUTIONS DIVERGE
SIGNIFICANTLY AFTER 72 HOURS...WITH THE GFS SWITCHING TO A 
FASTER/MORE PROGRESSIVE PATTERN EARLY NEXT WEEK. MEANWHILE THE
ECMWF IS STICKING WITH ITS SLOWER/MORE AMPLIFIED SOLUTION. SINCE
THE GFS IS MUCH DIFFERENT THAN ITS PRIOR RUNS...HAVE DECIDED TO
TREND TOWARD THE MORE CONSISTENT ECMWF FOR THIS FORECAST PACKAGE.
AS A RESULT...THINK CUT-OFF LOW OVER THE DESERT SOUTHWEST EARLY
NEXT WEEK WILL SLOWLY GET KICKED NORTHEASTWARD AHEAD OF A
DEVELOPING WESTERN CONUS LONG-WAVE TROUGH LATER IN THE WEEK.
TIMING STILL APPEARS TO BE WEDNESDAY NIGHT/THURSDAY...AT WHICH
TIME THERMAL PROFILES WILL BE WARM ENOUGH TO SUPPORT ALL RAIN.
WILL THEREFORE MAINTAIN MILD/DRY CONDITIONS FOR MONDAY THROUGH
WEDNESDAY...WITH HIGH TEMPERATURES CLIMBING INTO THE 40S. RAIN
CHANCES ARRIVE WEDNESDAY NIGHT INTO THURSDAY...WITH ABOVE NORMAL
TEMPERATURES PERSISTING THROUGH THE END OF THE WEEK.

BARNES
&&

.AVIATION...
ISSUED 1112 PM CST THU JAN 3 2013

VFR CONDITIONS ARE EXPECTED THIS FORECAST PERIOD. BACK EDGE OF LOW
VFR CIGS SHOULD BE EAST OF OUR TAF SITES BY 06Z WITH UPSTREAM OBS
INDICATING CLEAR SKIES. JUST ENOUGH WIND TO STIR THINGS UP AND KEEP
FOG FROM BEING A PROBLEM FOR OUR AREA OVERNIGHT SO WILL NOT INCLUDE
AT ANY TAF LOCATION. HIGH PRESSURE WILL PUSH SOUTH OF OUR AREA ON
FRIDAY ALLOWING A SSW FLOW TO PREVAIL THRU THE DAY. MAY SEE SOME
GUSTS TO AROUND 18 KTS AT TIMES DURING THE AFTN BEFORE WINDS DIMINISH
TO AROUND 10 KTS BY 00Z. 

SMITH
&&

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

$$