409
FXUS63 KILX 192330
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
530 PM CST TUE NOV 19 2024
KEY MESSAGES
- THERE IS A 50-60 PERCENT CHANCE OF ACCUMULATING SNOW (AT LEAST A
TENTH OF AN INCH) ON ELEVATED AND GRASSY SURFACES ALONG AND
NORTH OF THE I-74 CORRIDOR EAST OF BLOOMINGTON WEDNESDAY NIGHT
INTO THURSDAY.
- THURSDAY MORNING WILL SEE TEMPERATURES IN THE UPPER 20S TO LOWER
30S ACROSS CENTRAL ILLINOIS. WINDS GUSTING UPWARDS OF 30 MPH
WILL CONTRIBUTE TO WIND CHILL VALUES DIPPING INTO THE TEENS
NORTH OF I-72.
DISCUSSION
ISSUED AT 204 PM CST TUE NOV 19 2024
LATE THIS AFTERNOON, A DEEP AND OCCLUDED AREA OF LOW PRESSURE IS
CENTERED OVER FAR NORTHERN MINNESOTA WITH A DIFFUSE COLD FRONT
STRETCHING SOUTH ALONG THE MISSISSIPPI RIVER VALLEY. ALOFT, A
CLOSED UPPER LOW IS SPINNING OVER THE UPPER MIDWEST AND IS BEING
UNDERCUT BY A SHORTWAVE TROUGH MOVING EAST ACROSS IL/IN. AS THE
SHORTWAVE TROUGH CONTINUES TO EXIT THE REGION, STRONG SUBSIDENCE
IN ITS WAKE WILL OVERSPREAD CENTRAL ILLINOIS PROVIDING CONTINUED
CLEAR SKIES ACROSS THE REGION. IN ADDITION, STRONG COLD AIR
ADVECTION BEHIND THE WAVE/SURFACE FRONT WILL DRIVE GRADUALLY
COLDER CONDITIONS ACROSS CENTRAL ILLINOIS OVER THE NEXT COUPLE OF
DAYS. TEMPS ARE ONLY EXPECTED TO WARM TO NEAR 50 DEGREES WEDNESDAY
AFTERNOON FOLLOWED BY 40 DEGREES THURSDAY.
MEANWHILE, THE AFOREMENTIONED CLOSED UPPER LOW WILL MEANDER
SOUTHEAST ACROSS THE GREAT LAKES WEDNESDAY AND THURSDAY. FORECAST
SOUNDINGS THURSDAY MORNING INDICATE STEEP LOW LEVEL LAPSE RATES
WILL BE PRESENT WITH WEAK SURFACE BASED INSTABILITY POKING UP INTO
THE SNOW GROWTH ZONE AS A PINWHEELING VORT LOBE PUSHES ACROSS THE
AREA. THIS MAY ALLOW A FEW LIGHT SNOW SHOWERS OR FLURRIES FOR
FORM ESPECIALLY ALONG AND NORTH OF THE I-74 CORRIDOR. NBM
INDICATES AROUND A 50-60 PERCENT CHANCE OF ACCUMULATING SNOW (>0.1
IN) EAST OF BLOOMINGTON AND ALONG/NORTH OF THE I-74 CORRIDOR.
THAT BEING SAID, ANTECEDENT WARM PAVEMENT CONDITIONS SHOULD LIMIT
ACCUMULATIONS ON MANY SURFACES HELPING TO MITIGATE IMPACTS.
TEMPERATURES WILL BOTTOM OUT THURSDAY MORNING WITH LOWS IN THE
UPPER 20S TO AROUND 30 NORTH OF I-72 AND LOWER 30S SOUTH. THESES
TEMPERATURES IN COMBINATION WITH THE BREEZY WINDS STILL IN PLACE
WILL RESULT IN WIND CHILL VALUES DIPPING INTO THE TEENS FOR AT
LEAST PARTS OF CENTRAL ILLINOIS. THE GREATEST CHANCE FOR THIS IS
ALONG AND NORTH OF I-74 WHERE LREF INDICATES AROUND A 40-50
PERCENT CHANCE FOR WIND CHILL VALUES IN THE TEENS.
FRIDAY THROUGH THE WEEKEND, RIDGE OF HIGH PRESSURE WILL GRADUALLY
SHIFT EAST ACROSS THE MISSISSIPPI VALLEY RESULTING IN FAIR WEATHER
CONDITIONS ACROSS THE REGION TO END THE WEEK. LINGERING LOW LEVEL
CYCLONIC FLOW WILL RESULT IN ONGOING CLOUDINESS ACROSS CENTRAL
ILLINOIS FRIDAY AND NORTHWEST FLOW WILL KEEP TEMPS BELOW NORMAL
WITH HIGHS ONLY IN THE MID 40S. SURFACE RIDGE AXIS WILL BE OVER
THE MISSISSIPPI RIVER SATURDAY MORNING WITH FAVORABLE RADIATIONAL
COOLING CONDITIONS ESPECIALLY ACROSS PORTIONS OF WEST CENTRAL
ILLINOIS. TEMPS WILL DIP INTO THE UPPER 20S WEST OF THE ILLINOIS
RIVER AS A RESULT WITH LOW TEMPS AT OR BELOW FREEZING AREA-WIDE
AND ONLY WARM INTO THE MID TO UPPER 40S AGAIN SATURDAY AFTERNOON.
AS THE RIDGE AXIS SHIFTS TO OUR EAST OVER THE WEEKEND, A SMALL
WARMING TREND WILL ALLOW TEMPS TO RETURN CLOSER TO THE SEASONAL
NORMS WITH HIGHS IN THE LOWER TO MID 50S SUNDAY.
A ZONAL UPPER LEVEL PATTERN WILL BE IN PLACE TO START OFF NEXT
WEEK WITH THE MID LEVEL BAROCLINIC ZONE DRAPED WEST-TO-EAST ACROSS
THE MIDWEST. A LOW AMPLITUDE DISTURBANCE ALONG THIS BOUNDARY WILL
BRING THE NEXT CHANCE FOR PRECIPITATION TO CENTRAL ILLINOIS,
THOUGH TIMING DIFFERENCES BETWEEN THE MODELS PERSIST AT THIS
DISTANCE. TEMPERATURES ARE SUFFICIENTLY WARM TO FAVOR (90%
CONFIDENCE) PRECIP STAYING LIQUID DURING PASSAGE OF THIS SYSTEM.
DEUBELBEISS
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 530 PM CST TUE NOV 19 2024
A COUPLE OF DISTURBANCES WILL BRING PERIODS OF MID LEVEL CLOUD
COVER AND VERY LOW CHANCES FOR PRECIPITATION OVER THE UPCOMING
DAY. THE FIRST SHOULD ARRIVE 06Z-08Z AND DEPART AROUND 14Z, AND
THE NEXT SHOULD ARRIVE AFTER 18Z, WITH LOWERING CIGS INTO
WEDNESDAY NIGHT. THE ONLY CHANCES FOR PRECIPITATION HIGH ENOUGH
FOR MENTION THROUGH 00Z ARE AT KCMI 12Z-15Z. WINDS W-NW 4-8 KTS
THIS EVENING, INCREASING TO 15-20 KTS WITH GUSTS 25-30 KTS BY 18Z.
37
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
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