380
FXUS63 KILX 151730
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
1130 AM CST WED JAN 15 2025
KEY MESSAGES
- AS TEMPERATURES INCREASE TODAY, WIND CHILL VALUES WILL REMAIN
NEAR ZERO FOR MUCH OF THE AREA UNTIL AROUND NOON AND SINGLE
DIGITS MUCH OF THE DAY. EXPOSURE TO THESE CONDITIONS COULD
RESULT IN FROSTBITE.
- A BRIEF WARM-UP WILL CLOSE OUT THE WEEK BEFORE ANOTHER PUSH OF
VERY COLD TEMPERATURES ARRIVES OVER THE WEEKEND. CONFIDENCE IS
CURRENTLY HIGH (70% CHANCE OR GREATER) THAT WIND CHILL VALUES
WILL BE COLDER THAN 10 BELOW ZERO SUNDAY NIGHT AND MONDAY NIGHT.
- PATCHY FREEZING FOG IS A POSSIBILITY THURSDAY NIGHT, THOUGH
FORECAST CONFIDENCE IS CURRENTLY LOWER THAN 50%.
- LIGHT RAIN IS LIKELY (70% CHANCE OR GREATER) FRIDAY EVENING IN
AREAS EAST OF I-55, BRIEFLY MIXING WITH LIGHT SNOW BY SATURDAY
MORNING. THE PROBABILITY FOR ACCUMULATING SNOW IS VERY LOW.
UPDATE
ISSUED AT 1020 AM CST WED JAN 15 2025
MID LEVEL CLOUD COVER AHEAD OF A WARM FRONT NEAR THE MISSOURI
RIVER HAS BEGUN TO STREAM ACROSS CENTRAL IL, ENDING OR MUTING THE
SUNSHINE ACROSS THE AREA, AS A SHORTWAVE APPROACHES THE GREAT
LAKES REGION FROM THE NORTHWEST. WINDS HAVE ALSO BEGUN TO INCREASE
FROM THE SOUTHWEST, REPLACING THE SUB-ZERO TEMPERATURES FROM THIS
MORNING WITH SUB-ZERO WIND CHILLS FOR THE TIME BEING. TEMPERATURES
SHOULD CONTINUE RISING TO AROUND 20 DEGREES FOR HIGHS TODAY, WITH
WIND CHILLS REMAINING IN THE SINGLE DIGITS MUCH OF THE DAY AS
WINDS INCREASE TO AROUND 10 MPH. UPDATES THIS MORNING FOR AN
INCREASE IN CLOUD COVER.
37
DISCUSSION
ISSUED AT 1257 AM CST WED JAN 15 2025
MODIFIED SURFACE HIGH PRESSURE CONTINUES BUILDING ACROSS CENTRAL
ILLINOIS THIS MORNING AHEAD OF A LOW-LEVEL RIDGE AXIS. STRONG
RADIATIONAL COOLING BENEATH A RESIDUAL SNOWPACK HAS RESULTED IN
VERY COLD TEMPERATURES THIS MORNING, GENERALLY NEAR ZERO, GIVE OR
TAKE A FEW DEGREES. LIGHT WIND OR NO WIND HAS LARGELY MITIGATED
THE WIND CHILL EFFECT, BUT THERE ARE A COUPLE ASOS/AWOS SITES
READING WIND CHILL VALUES AS LOW AS TEN BELOW ZERO.
A WEAK COLD FRONT WILL PUSH INTO THE REGION TONIGHT AS STRONG
SHORTWAVE ENERGY DIGS INTO THE GREAT LAKES REGION. THIS FEATURE
COULD ALLOW FOR A BRIEF PERIOD OF WARM-ADVECTION SNOW OR FLURRIES
IN AREAS NORTH OF A GALESBURG TO TERRE HAUTE LINE, BUT FORECAST
CONFIDENCE IS VERY LOW GIVEN HOW DISJOINTED COLUMN MOISTURE (RH)
APPEARS IN MODEL SOUNDINGS.
TEMPERATURES WILL SURGE INTO THE 30S ON THURSDAY AS THE EFFECTS
OF COMPRESSIONAL WARMING ADVECT INTO THE MIDWEST FROM THE PLAINS.
THE WARMING TREND THEN CONTINUES INTO FRIDAY AS GUSTY SOUTHERLY
FLOW MOVES IN AHEAD OF A FRONTAL SYSTEM, PROVIDING TEMPERATURES IN
THE 40S.
SOME CONCERN FOR SHALLOW DENSE FOG REMAINS THURSDAY NIGHT AS MUCH
WARMER LOW- LEVEL AIR BEGINS TO ADVECT OVERTOP A DIMINISHING
SNOWPACK. A QUICK GLANCE AT T/TD SPREADS FROM THE NBM SUGGESTS
THAT THE REAL HONEST PUSH OF WARM ADVECTION HAS BEEN DELAYED UNTIL
FRIDAY AFTERNOON, WITH SFC TEMPS STILL IN THE MID-TO-UPPER 20S
THURSDAY NIGHT. THIS WOULD SUGGEST THAT ANY FOG THAT MIGHT DEVELOP
DURING THIS TIMEFRAME WOULD BE FREEZING FOG. OVERALL, FORECAST
CONFIDENCE IN FOG DEVELOPMENT REMAINS AT LESS THAN 50%, BUT THERE
IS SOME SIGNAL AMONG MODEL SOUNDINGS (GFS, SREF, NAM3KM) FOR IT.
WE HAVE MADE MENTION OF PATCHY FREEZING FOG IN OUR GRIDDED
FORECAST, BUT WILL REFRAIN FROM MESSAGING IT UNTIL CONFIDENCE
INCREASES.
LIGHT PRECIP WILL SPREAD INTO ILLINOIS BY FRIDAY EVENING AS THE
WINTER OF PHASED WAVES OVER THE CENTRAL U.S. CONTINUES. FORECAST
GUIDANCE REMAINS IN EXCELLENT AGREEMENT THAT LOW-LEVEL
TEMPERATURES WILL BECOME WARM ENOUGH TO SUPPORT RAIN IN AREAS EAST
OF THE ILLINOIS RIVER VALLEY, AT LEAST AT ONSET. IT THEN BECOMES A
RACE BETWEEN WHEN THE LOW-LEVEL MOISTURE DEPARTS VERSUS WHEN THE
COLD TEMPERATURES SPILL INTO THE REGION. FOR NOW, THE MAJORITY OF
ENSEMBLE GUIDANCE SUPPORTS AT LEAST A BRIEF CHANGE OVER TO SNOW,
BUT WITH A VERY LOW PROBABILITY (< 30% CHANCE) FOR ACCUMULATING
SNOW.
THE RETURN OF VERY COLD TEMPERATURES IS LIKELY BY SUNDAY NIGHT AS
CROSS-POLAR FLOW DISBURSES ANOTHER LOBE OF ARCTIC AIR TO THE
CENTRAL U.S. THERE IS CURRENTLY A HIGH CONFIDENCE (70% CHANCE OR
GREATER) IN WIND CHILL VALUES COLDER THAN TEN BELOW ZERO BOTH
SUNDAY NIGHT AND MONDAY NIGHT. TEMPERATURES THEN LOOK TO MODERATE
A LITTLE WARMER BY WEDNESDAY, BUT THE CONSENSUS AROUND HERE IS
THAT WE WILL REMAIN IN THE TANK THROUGH LATE JANUARY BEFORE WE GET
A BONA FIDE THAW BY EARLY FEBRUARY.
MJA
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1130 AM CST WED JAN 15 2025
A WEATHER SYSTEM WILL BRUSH PAST CENTRAL IL TONIGHT, WHICH WILL
BRING SCATTERED SNOW FLURRIES AND LOWER CIGS APPROACHING 3000 FT
AGL, MAINLY FOR THE I-74 TERMINALS KPIA-KBMI-KCMI. THERE REMAINS
SOME UNCERTAINTY IN HEIGHT OF CIGS AND POTENTIAL FOR BRIEF
IFR/MVFR VSBYS IN -SHSN. ANY BRIEF IFR/MVFR CONDITIONS WOULD
LIKELY TAKE PLACE BETWEEN 05Z AND 10Z. WEST WINDS AT THE 2000 FT
LEVEL LOOK TO REACH AROUND 40 KTS FROM 06Z-09Z, AND WILL LIKELY
PRODUCE SOME LOW LEVEL WIND SHEAR. SURFACE WINDS SW 07-14KTS UNTIL
AROUND 09Z, THEN SHIFTING TO NW AND INCREASING TO 10-15 KTS WITH
GUSTS OVER 20 KTS BY AROUND 15Z.
37
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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