317
FXUS63 KILX 201734
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1134 AM CST FRI DEC 20 2024
KEY MESSAGES
- LIGHT SNOW IS EXPECTED THROUGH LATE THIS MORNING. A LIGHT
DUSTING OF SNOW IS POSSIBLE NORTH OF A SPRINGFIELD TO EFFINGHAM
LINE, WITH ACCUMULATIONS UP TO 1 INCH MOST LIKELY NORTH OF I-74.
- NORTH-NORTHWEST WINDS WILL BE BRISK TODAY WITH GUSTS UP TO 35
MPH THROUGH THIS AFTERNOON.
- COOL AND DRY WEATHER THIS WEEKEND WILL BE REPLACED BY MILD AND
UNSETTLED CONDITIONS BEGINNING NEXT WEEK.
UPDATE
ISSUED AT 941 AM CST FRI DEC 20 2024
THE AREA OF LIGHT SNOW ACROSS CENTRAL AND EASTERN ILLINOIS THIS
MORNING IS QUICKLY TAPERING TO FLURRIES. UPSTREAM OBS ACROSS SOUTH
CENTRAL WISCONSIN AND NORTHERN ILLINOIS ARE ALREADY PAINTING THE
PICTURE OF HOW THIS AFTERNOON WILL LOOK AROUND HERE. THE
OVERWHELMING MAJORITY OF MODEL GUIDANCE SUPPORTS A LARGE POCKET OF
CLEARING MOVING SOUTHWARD ACROSS CENTRAL ILLINOIS BY AFTERNOON,
AND THIS IDEA MAKES SENSE GIVEN THE LARGE SCALE SUBSIDENCE/RIDGING
MOVING IN BEHIND THE DEPARTING UPPER-LEVEL SHORTWAVE TROUGH. WITH
AT LEAST A FEW HOURS OF SUNSHINE THIS AFTERNOON, TEMPERATURES ARE
STILL ON TRACK TO REACH INTO THE MID 30S, THOUGH WITH THE FREQUENT
NORTHERLY WIND GUSTS BLOWING BETWEEN 20-30 MPH, IT WILL FEEL MUCH
COOLER THAN THAT. NO CHANGES HAVE BEEN MADE IN THE FORECAST FOR
TONIGHT THROUGH SATURDAY.
MJA
DISCUSSION
ISSUED AT 1133 AM CST FRI DEC 20 2024
SURFACE LOW PRESSURE IS CENTERED OVER NORTHEAST ILLINOIS/NORTHERN
INDIANA THIS MORNING WITH A COLD FRONT STRETCHED SOUTH OF THERE
THROUGH WESTERN INDIANA AND KENTUCKY. BREEZY AND COOL CONDITIONS
HAVE FILLED IN BEHIND THE FRONT WITH TEMPERATURES IN THE UPPER 20S
TO LOW 30S. AN UPPER SHORTWAVE TROUGH CURRENTLY CENTERED OVER
EASTERN IOWA WILL DIVE SOUTHEAST THIS MORNING, BRINGING A PERIOD OF
LIGHT SNOW TO MOST NORTH OF I-70. SNOW ACCUMULATIONS LOOK RELATIVELY
LIGHT WITH THE 20.00Z HREF SHOWING DECENT PROBABILITIES FOR A
DUSTING NORTH OF A SPRINGFIELD TO EFFINGHAM LINE, WITH A 30-50%
CHANCE FOR AT LEAST 0.5 INCH NORTH OF I-74. COOLER TEMPERATURES WILL
FAVOR A FLUFFIER SNOW VARIETY WITH BREEZY WINDS LEADING TO BLOWING
OF FALLING SNOW. THOSE TRAVELING SHOULD BE PREPARED FOR SLIPPERY
ROADS AND REDUCED VISIBILITIES.
SNOW WILL COME TO AN END LATER THIS MORNING, WITH SOME LINGERING
ACTIVITY CONTINUING THIS AFTERNOON CLOSER TO THE INDIANA BORDER.
SURFACE HIGH PRESSURE WILL SINK INTO THE PLAINS STATES, ACTING TO
PUSH THE SURFACE LOW FURTHER EAST OF HERE. SURFACE WINDS WILL VEER
TO THE NORTH, SETTING UP A LAKE-EFFECT SNOW BAND OVER LAKE MICHIGAN.
IN FACT, THE FETCH OF THE WIND OVER THE LAKE (N-NE) WILL BRING SOME
LIGHT SNOW OR FLURRIES TO THOSE IN FAR EAST-CENTRAL ILLINOIS THROUGH
THIS AFTERNOON. LITTLE TO NO ACCUMULATION IS EXPECTED WITH THE LAKE
ENHANCED ACTIVITY.
THE SURFACE RIDGE WILL INCH CLOSER TO THE AREA TONIGHT, ALLOWING
WINDS TO BEGIN RELAXING. LOW STRATUS WILL BE SLOW TO DEPART TODAY,
BUT SUBSIDENCE TIED TO THE SURFACE HIGH/UPPER RIDGE SHOULD AID IN
SCATTERING THINGS OUT BY THIS EVENING OR OVERNIGHT. A FEW MID-LEVEL
CLOUDS WILL FILL IN BEHIND IT, BUT SHOULD BE THIN ENOUGH TO ALLOW
TEMPERATURES TO DROP INTO THE TEENS TO LOW 20S OVERNIGHT. SURFACE
RIDGING WILL KEEP THINGS COOL AND DRY THROUGH SATURDAY NIGHT WITH
SOUTHERLY RETURN FLOW SHAPING UP FOR SUNDAY AS THE HIGH SPREADS INTO
THE EASTERN US.
MILD AND UNSETTLED WEATHER SHAPES UP GOING INTO THE HOLIDAY WEEK.
TEMPERATURES THROUGH THE WEEK WILL GRADUALLY WARM WITH HIGHS
AVERAGING ABOUT 5-10 DEGREES ABOVE NORMAL THROUGH WEDNESDAY, THEN
APPROACHING 15 DEGREES ABOVE NORMAL BY THE END OF THE WEEK. DAILY
PRECIPITATION CHANCES WILL ACCOMPANY THE MILDER TEMPERATURES WITH
THE FIRST WAVE DROPPING A COLD FRONT THROUGH THE AREA ON MONDAY.
THIS FRONT WILL STALL OUT NEAR THE OHIO VALLEY, KEEPING
PRECIPITATION CHANCES IN PARTS OF THE AREA THROUGH AT LEAST
TUESDAY. SOME DIFFERENCES REMAIN BEYOND THEN, BUT A SERIES OF
FRONTAL SYSTEMS MAY REGENERATE ACTIVITY ALONG THE FRONT AS IT GETS
PUSHED BACK NORTHWARD FROM CHRISTMAS DAY (WED) THROUGH THE END OF
THE WEEK. THE NBM SPLATTERS AT LEAST 20% POPS THROUGH THE ENTIRE
WEEK WITH FURTHER REFINEMENTS EXPECTED IN FUTURE UPDATES.
NMA
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1124 AM CST FRI DEC 20 2024
UPSTREAM OBSERVATIONS ACROSS NORTHERN ILLINOIS INDICATE A STEADY
IMPROVEMENT TO VFR THIS AFTERNOON AS A DRIER/SUBSIDENT AIRMASS
WORKS IN FROM THE NORTH. THE EXCEPTION COULD BE AT BMI/CMI WHERE
MVFR CEILINGS COULD LINGER A LITTLE LONGER INTO THIS EVENING AS
N/NE WINDS STEER SOME SHALLOW MOISTURE/CLOUDS FROM LAKE MICHIGAN
INTO EASTERN ILLINOIS. HAVE OPTED TO SCATTER MVFR CEILINGS AT
BMI BY 21Z AND CMI BY 23Z DESPITE MODEL TRENDS CLEARING BOTH
TERMINALS TO VFR.
OTHERWISE, WINDS WILL STEADILY DIMINISH THIS EVENING AS SURFACE
LOW PRESSURE DEPARTS THE REGION, AND WE WILL BE LEFT WITH LIGHT
NORTHERLY WINDS GOING INTO SATURDAY MORNING.
MJA
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page