FXUS63 KILX 231139
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
539 AM CST WED DEC 23 2009
.DISCUSSION...
ISSUED 308 AM CST WED DEC 23 2009
HIGH PRESSURE RIDGE HAS SLID TO THE NORTH EAST AS SOUTHERLY WINDS
PICK UP IN THE SRN MISS RIVER VALLEY...AND A DEVELOPING FRONTAL
BOUNDARY PUSHES INTO SRN PORTIONS OF THE STATE AHEAD OF THE SFC
LOW IN SRN PLAINS. MUCH OF CENTRAL AND NRN ILLINOIS ON THE EDGE OF
FREEZING AS OVERNIGHT TEMP DROP IS COUNTERED WITH WARMER AIR
TRYING TO MAKE ITS WAY INTO THE MIDWEST. SOME FZ DRIZZLE AND GLAZING
STILL EXPECTED TO THE NORTH IN THE EARLY HOURS THIS MORNING...AND
GOING HEADLINES HAVE A PRETTY GOOD GRIP ON IT. ELSEWHERE...SHOWERS
MOVING ACROSS SRN IL...AND THUNDER ALREADY IN THE SHOWERS ON THE
NOSE OF THE NOCTURNAL JET TO THE SW. FORECAST SEEMS TO BE HOLDING
STEADY FOR NOW AS THE MODELS ARE MAINTAINING SOME SEMBLANCE OF
CONSISTENCY. NAM/WRF IN THE SHORT TERM AND BLENDING THROUGH THE
MED RANGE. CLOUDY AND WET IS STILL THE RULE UNTIL FRI AFTERNOON
AS THE CWA MAKES THE SHIFT OVER TO SNOW.
SHORT TERM...TODAY AND TOMORROW...
SHOWERS PUSHING INTO THE CENTRAL PORTIONS OF THE STATE...BUT JUST
DRIZZLE ALONG AND NORTH OF INTERSTATE 74. THAT FAR NORTH...COLD
AIR IS STILL IN PLACE AND GLAZING OF ELEVATED AND UNTREATED ROADS
IS OCCURRING. KEEPING THE MENTION OF SOME FZ DRIZZLE THROUGH THE
MORNING...AND GOING ADVSY FOR LIGHT ICING WILL CONTINUE. DO NOT
SEE ENOUGH EVIDENCE IN THE EARLY MORNING HOURS TO REDUCE IT AT
ALL...ESP IN ADVANCE OF PEOPLE GETTING ON THE ROAD. AS THE DAY
PROGRESSES...CWA WILL GO TO ALL RAIN. THUNDER ALREADY ON
APPROACH...SHOULD MAINLY EFFECT THE SRN HALF OF THE STATE...CLOSER
TO THE DEVELOPING LOW AND FRONTAL BOUNDARY.
COLD AND BLUSTERY AS THE INCREASING PRESSURE GRADIENT RESULTS IN
WINDS AROUND 20 KTS TOMORROW...GUSTING TO 30 KTS. THO TEMPS WILL
BE APPROACHING UPPER 30S/NEAR 40...THE WINDS WILL DROP WIND CHILLS
INTO THE 20S. HEAVY RAINS ARE LIKELY...WITH 2 TO 3 INCHES EXPECTED
FROM TODAY THROUGH CHRISTMAS EVE. FLOOD WATCH IN EFFECT THROUGH
UNTIL CHRISTMAS MORNING. LOCALLY HIGHER PRECIP TOTALS WILL OCCUR
IN AREAS WITH THUNDERSTORM DEVELOPMENT. VERY WET HOLIDAY IN STORE...AND
TRAVELERS SHOULD EXERCISE EXTREME CAUTION AND LEAVE PLENTY OF
TIME TO REACH THEIR DESTINATION. HEAVY RAINS CAN QUICKLY REDUCE
VISIBILITY...AND NEVER CROSS WATER COVERED ROADS.
LONG TERM...FRIDAY THROUGH SUNDAY...
HOLDING TO PREVIOUS FORECAST...BUT WITH SOME DRYING OUT
ALOFT...WILL LOSE ICE CRYSTALS WITH WEDGE OF DRY AIR WRAPPING
AROUND THE SYSTEM...AND WITH SFC TEMPS ABOVE FREEZING...WILL STAY
RAIN A BIT LONGER INTO FRIDAY MORNING. IN THE PREDAWN HOURS OF
CHRISTMAS...WILL LIKELY SEE A MIX OF MOSTLY RAIN WITH A FEW SNOW
FLAKES IN THE WEST...THEN IN THE EAST FRI MORNING...BEFORE FINALLY
GOING OVER TO ALL SNOW FRI AFTERNOON...AS THE SYSTEM MOVES NORTH.
SYSTEM DRIFTING A BIT FOR THE WEEKEND...LEAVING MUCH OF CWA IN AN
AREA OF LIGHT SNOW/FLURRIES THROUGH SATURDAY BEFORE FINALLY
LIFTING OUT OF THE AREA.
HJS
&&
.AVIATION...
ISSUED 539 AM CST WED DEC 23 2009...FOR THE 12Z TAFS
RAIN HAS OVERSPREAD THE TAF SITES...ALONG WITH WARMER AIR. WE DO
NOT EXPECT ANY FREEZING CONDITIONS AT THE NORTHERN TERMINALS OF
PIA/BMI ANYMORE THIS MORNING. WILL CONTINUE WITH PREDOMINANT RAINS
AT ALL TAFS OVER THE NEXT 24 HOURS. THERE MAY BE SOME BREAKS IN
THE RAIN...BUT DRIZZLE WILL LIKELY LINGER WHEN RAIN DIMINISHES.
WILL CONTINUE WITH IFR/LIFR CIGS AND IFR VIS OVER THE ENTIRE TAF
PERIOD. LITTLE RELIEF EXPECTED IN CLOUD HEIGHTS THROUGH THURSDAY
MORNING...AS STEADY WAA ALOFT INCREASES MOISTURE DEPTH WITH TIME.
GUID IS INDICATING SOME VLIFR VIS AT PIA/BMI FOR A TIME THIS
AFTERNOON AS THE MID LEVEL WARM ADVECTION BECOMES MAXIMIZED IN OUR
N CWA.
SOUTHEAST WINDS WILL INCREASE THIS MORNING...WITH GUSTS TO 25-30
KTS AT TIMES THIS AFTERNOON. WILL KEEP GUSTS GOING ALL NIGHT...BUT
THEY MAY BE LESS FREQUENT AFTER SUNSET.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM NOON CST TODAY THROUGH THURSDAY EVENING FOR
ILZ027>031-036>038-040>057-061>063-066>068-071>073.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR ILZ027>031-037-
038-045-046.
&&
$$
