FXUS63 KILX 101101
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
501 AM CST THU DEC 10 2009
.DISCUSSION...
ISSUED 221 AM CST THU DEC 10 2009
MODERATING TEMPERATURES WILL BE ON TAP FOR THE NEXT FEW
DAYS...BEFORE THE NEXT APPROACHING DISTURBANCE POTENTIALLY BRINGS
A PERIOD OF WINTRY PRECIPITATION INTO THE AREA SATURDAY NIGHT
INTO SUNDAY.
WINTER STORM THAT IMPACTED THE REGION YESTERDAY IS NOW LOCATED
OVER SOUTHERN QUEBEC...WITH TRAILING COLD FRONT PUSHING AS FAR
SOUTH AS THE GULF OF MEXICO. STILL SOME LINGERING CLOUDS/FLURRIES
ACROSS EAST-CENTRAL ILLINOIS...BUT SATELLITE IMAGERY INDICATES
CLEARING SKIES AS HIGH PRESSURE BUILDS IN FROM THE WEST.
SHORT TERM...TODAY THROUGH SATURDAY
AS DEEP LOW PRESSURE MOVES FURTHER AWAY...PRESSURE GRADIENT WILL
CONTINUE TO WEAKEN TODAY. HOWEVER...WITH CENTER OF HIGH PRESSURE
SLIDING BY TO THE SOUTH...GRADIENT WILL REMAIN TIGHT ENOUGH TO
PRODUCE BREEZY CONDITIONS. BUFKIT MOMENTUM TRANSFER SUGGESTS GUSTS
OF 20 TO 25 MPH ACROSS THE WEST AND PERHAPS AS HIGH AS 30 MPH
ALONG AND EAST OF I-57. PLENTY OF SUNSHINE IS IN STORE...THANKS TO
SUBSTANTIAL DRYING IN THE WAKE OF THE DEPARTING SYSTEM. DESPITE
FULL SUN...TEMPS WILL STRUGGLE TO RISE FROM BITTERLY COLD EARLY
MORNING READINGS IN THE SINGLE DIGITS AND TEENS. AFTERNOON HIGH
TEMPS WILL ONLY REACH THE TEENS AND LOWER 20S IN MOST AREAS...WITH
SLIGHTLY WARMER MIDDLE 20S SOUTH OF I-70. ANOTHER VERY COLD NIGHT
IS COMING UP TONIGHT...WITH CLEAR SKIES AND LIGHT WINDS ALLOWING
TEMPS TO DIP BACK INTO THE SINGLE DIGITS AND TEENS.
AS HIGH PRESSURE MOVES ACROSS THE GULF COAST STATES...SOUTHERLY
RETURN FLOW WILL DEVELOP ON FRIDAY...LEADING TO MODERATING TEMPS.
SHOULD SEE HIGHS BACK INTO THE LOWER TO MIDDLE 30S...EXCEPT ACROSS
THE SNOW-COVERED AREAS NORTHWEST OF THE ILLINOIS RIVER WHERE
READINGS WILL REMAIN IN THE 20S. EVEN WARMER WEATHER IS
ANTICIPATED FOR SATURDAY...WITH HIGHS WELL INTO THE 30S AND EVEN
REACHING THE LOWER 40S SOUTHEAST.
LONG TERM...SUNDAY THROUGH WEDNESDAY
ZONAL FLOW PATTERN WILL SET UP OVER THE WEEKEND...ALLOWING A
SERIES OF WEAK/FAST-MOVING DISTURBANCES TO TRACK FROM WEST TO EAST
ACROSS THE COUNTRY. FIRST WAVE OF INTEREST COMES OFF THE PACIFIC
ON SATURDAY...THEN RACES INTO THE REGION SATURDAY NIGHT INTO
SUNDAY MORNING. NAM-WRF/GFS ARE IN FAIRLY GOOD AGREEMENT
CONCERNING THE TRACK AND TIMING OF THIS SYSTEM...WITH BOTH MODELS
PRODUCING PRECIP ACROSS CENTRAL ILLINOIS SATURDAY NIGHT. DESPITE
FAIRLY ROBUST QPF...THINK MOISTURE RETURN FROM THE GULF MAY BE A
BIT OVERDONE...DUE TO STRONG SURFACE HIGH PRESSURE ANCHORED OVER
THE DEEP SOUTH JUST 24 HOURS PRIOR TO THE ARRIVAL OF THE SYSTEM.
FORECAST SOUNDINGS INDICATE A SHALLOW MOIST LAYER...SUGGESTING
ONLY VERY LIGHT PRECIP. THERMAL PROFILES SHOW A BRIEF PERIOD
BETWEEN 00Z AND 06Z SUN WHEN ICE CRYSTALS ARE PRESENT...BEFORE
MID-LEVEL DRYING ELIMINATES CRYSTALS AFTER 06Z. BOTH NAM-WRF/GFS
SUGGEST A FEW SNOW FLURRIES INITIALLY...WITH PRECIP CHANGING TO
FREEZING DRIZZLE AFTER MIDNIGHT...THEN PERSISTING INTO SUNDAY
MORNING BEFORE COMING TO AN END BY AROUND MIDDAY. SURFACE TEMPS
SUNDAY MORNING MAY WARM ENOUGH TO ALLOW THE PRECIP TO CHANGE TO
DRIZZLE...ESPECIALLY ALONG AND SOUTH OF I-72.
AFTER THAT...MODELS ARE CONTINUING TO SHOW A COLD FRONT SWINGING
INTO CENTRAL ILLINOIS ON MONDAY. WILL CONTINUE TO CARRY JUST
SLIGHT CHANCE POPS WITH THE FRONT...WITH TEMPS AHEAD OF THE
BOUNDARY APPROACHING THE 40 DEGREE MARK ON BOTH SUNDAY AND MONDAY.
AFTER THAT...A RETURN TO COLDER WEATHER IS IN STORE FOR THE
REMAINDER OF THE EXTENDED.
BARNES
&&
.AVIATION...
ISSUED 501 AM CST THU DEC 10 2009
VFR CONDITIONS WILL PREVAIL NEXT 24HRS AT ALL TAF SITES. MIGHT SEE
SOME CLOUD STREETS FORMING OFF THE SNOW PACK TO THE NORTHWEST OVER
PIA AND BMI...BUT CONTINUED WINDY CONDITIONS SHOULD PREVENT THIS.
THEREFORE WILL HAVE CLEAR SKIES NEXT 24HRS. WESTERLY WINDS WILL BE
GUSTY AGAIN TODAY...BUT ONLY AROUND 25-30MPH. THEN WINDS BECOME
MORE SOUTHWESTERLY TONIGHT...AND LIGHTER.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR ILZ027>031-
036>038-040-041.
&&
$$
