324
FXUS63 KILX 120948
AFDILX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE LINCOLN IL
448 AM CDT THU MAR 12 2026
KEY MESSAGES
- WINDY CONDITIONS ARE EXPECTED TONIGHT INTO FRIDAY MORNING.
SUSTAINED WINDS OF 20-30 MPH ARE EXPECTED, WITH GUSTS UP TO 50
MPH. WINDS WILL BE SOUTHWESTERLY TONIGHT, TURNING TO WESTERLY
INTO FRIDAY.
- A WEEKEND SYSTEM WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS
ON SUNDAY, FOLLOWED BY SHARPLY COLDER TEMPERATURES, WINDY
CONDITIONS, AND A CHANCE OF SNOW SUNDAY NIGHT INTO MONDAY.
THERE IS A 30-60% CHANCE FOR WIND CHILLS BELOW ZERO BOTH MONDAY
AND TUESDAY MORNINGS NORTH OF I- 72/DANVILLE.
DISCUSSION
ISSUED AT 254 AM CDT THU MAR 12 2026
*** WINDY TONIGHT INTO FRIDAY ***
THE PRIMARY CONCERN THROUGH THE END OF THE WORK WEEK IS WINDY
CONDITIONS TONIGHT INTO FRIDAY MORNING AS A SUB-990 MB SFC TRACKS
ACROSS THE UPPER MIDWEST. THE TIGHT PRESSURE GRADIENT BETWEEN THIS
SFC LOW AND A SFC HIGH OVER THE SE CONUS IS EXPECTED TO RESULT IN
SUSTAINED WIND SPEEDS APPROACHING 25-30 MPH, OUT OF THE SSW, LATE
THIS EVENING INTO THE OVERNIGHT HOURS. THERE IS A 50-80% CHANCE
FOR SUSTAINED WINDS OVER 25 MPH NORTH OF I-70 (LOWER PROBABILITIES
TO THE SOUTH).
THE GUST POTENTIAL IS LESS CERTAIN OVERNIGHT, OWING TO QUESTIONS
AS TO WHETHER OR NOT A NEAR SFC STABLE LAYER DEVELOPS. IF SOME
DEGREE OF MIXING CAN PERSIST INTO THE NIGHT, FORECAST SOUNDINGS
SHOW WINDS OF 45-50 MPH LESS THAN 1000 FEET AGL, AND 50-60 MPH
BETWEEN 1-2 KFT AGL. THE LATEST HREF (12.00Z) HAS MEAN GUSTS OF
45-55 MPH OVERNIGHT, BUT CAMS CAN OVERDO MIXING DURING THE
NOCTURNAL PERIOD. AT ANY RATE, THERE IS ENOUGH POTENTIAL FOR
STRONG WINDS/GUSTS OVERNIGHT THAT A WIND ADVISORY FEELS NECESSARY.
INTO FRI MORNING, WINDS TURN TO WESTERLY. PBL MIXING QUICKLY
DEEPENS WHICH COULD OFFER A WINDOW OF EVEN HIGHER GUSTS (6AM -
NOON FRI). FORECAST SOUNDINGS SUGGEST EASY MIXING OF 40-50 MPH
GUSTS TO THE SFC (NORTH OF I-72), WITH POTENTIAL FOR AREAS
ALONG/NORTH OF I-74 TO APPROACH HIGH WIND WARNING CRITERIA (GUSTS
OVER 58 MPH). THE INTENSITY OF THE WINDS SHOULD WEAKEN INTO THE
AFTERNOON AS THE SYSTEM SHIFTS EAST.
CAMS HINT AT LIGHT PRECIP CHANCES NEAR/NORTH OF I-74 LATE THIS
EVENING INTO TONIGHT, BUT FORECAST SOUNDINGS APPEAR VERY DRY IN
THE LOW LEVELS. DESPITE THE DRY AIR, THE COMBO OF STRONG LOW-LEVEL
WAA AND A BAND OF 850-MB FGEN IS ENOUGH OF A FORCING SIGNAL TO
KEEP ME FROM REMOVING THE LOW PRECIP CHANCES FROM THE FORECAST
(20-40%, MAINLY NORTH OF A CANTON TO HOOPESTON LINE). PRECIP
CHANCES FROM THIS SYSTEM INCREASE NORTH OF I-80. HIGH TEMPERATURES
WILL BE SEASONABLE TO SLIGHTLY ABOVE NORMAL TODAY AND FRIDAY.
MOST OF THE AREA WILL BE IN THE 50S, BUT AREAS SOUTH OF I-70 COULD
REACH 60 ON FRI. LOWS WILL BE SEASONABLY MILD THURS NIGHT DUE TO
THE STRONG SOUTHERLY FLOW, STAYING NEAR 40 DEGF.
*** SATURDAY INTO NEXT WEEK ***
ATTENTION THEN TURNS TO A LARGE MID-LATITUDE CYCLONE, WHICH WILL
START DEVELOPING IN THE LEE OF THE ROCKIES ON SAT, RESULTING IN
EASTERLY FLOW DEVELOPING LOCALLY. OVER THE COURSE OF SAT EVE TO
MIDDAY SUN, A DEEPENING SFC LOW IS EXPECTED TO TRACK FROM CO
TOWARDS WEST-CENTRAL IL. ANOTHER ROUND OF BREEZY SOUTHERLY FLOW
WILL PUSH TEMPS BACK ABOVE NORMAL, WITH HIGHS IN THE 60S ACROSS
THE WARM SECTOR BY MIDDAY SUN, WHICH BASED ON THE CURRENT LOW
TRACK SHOULD INCLUDE MOST OF CENTRAL IL. WILL NEED TO MONITOR THE
SEVERE STORM POTENTIAL WITH THIS SYSTEM, BUT EARLY INDICATIONS ARE
THAT MOISTURE RETURN WILL NOT BE NEARLY AS ROBUST AS OUR PREVIOUS
EVENT, WITH FORECAST DEWPOINTS IN THE LOW TO MID 50S (RATHER THAN
THE MID/UPPER 60S). GIVEN THE DEEPENING, EXPANSIVE SFC LOW, WIND
SHEAR IS UNLIKELY TO BE A LIMITING FACTOR, WITH CURRENT GUIDANCE
DEPICTING EFFECTIVE SHEAR OF 45-50 KTS. AS IS OFTEN THE CASE IN
EARLY SEASON SEVERE EVENTS, INSTABILITY WILL BE THE MOST LIKELY
LIMITING FACTOR.
GUIDANCE DOES SUGGEST A STRONG COLD FRONT SWEEPING ACROSS THE AREA
DURING THE AFTERNOON. GIVEN THE DYNAMIC WIND FIELDS, THINK A WIND
THREAT WOULD BE REASONABLE IN THIS SCENARIO, WITH OTHER SEVERE
THREATS LESS CERTAIN. IT IS WORTH NOTING THOUGH THAT CURRENT
GUIDANCE HAS PERHAPS THE MOST FAVORABLE SETUP FOR SEVERE STORMS IN
THE ILX CWA IN TERMS OF SFC LOW TRACK AND DIURNAL TIMING. IF THE
LOW TRACK SHIFTS SOUTH, OR THE SYSTEM TRENDS FASTER/SLOWER, THAT
COULD REDUCE THE SEVERE THREAT RELATIVE TO THE SCENARIO DESCRIBED
ABOVE. AT ANY RATE, THIS WILL BE SOMETHING TO MONITOR INTO THE
WEEKEND.
* WINTER MAKES A RETURN *
THAT AFOREMENTIONED STRONG COLD FRONT WILL SWEEP A SHARPLY COLD
AIRMASS INTO THE REGION, WITH ENSEMBLE MEAN 850MB TEMPS FALLING TO
-15 DEGC BY MIDDAY MON. INTO SUN EVENING, A TRANSITION FROM RAIN TO
SNOW APPEARS POSSIBLE. FORECAST SOUNDINGS ALSO APPEAR QUITE WINDY,
WITH DEEP MIXING IN THE CAA REGIME SUGGESTING ANOTHER WIND ADVISORY
COULD BE NEEDED SUN NIGHT INTO MON. WITH SNOW POSSIBLE AND STRONG
WINDS APPEARING LIKELY, REDUCED VISIBILITY MAY BE A CONCERN. SNOW
ACCUMULATIONS ARE IN PLAY WITH THIS SYSTEM, ALTHOUGH A FEW DAYS OF
ABOVE NORMAL TEMPS IN ADVANCE OF THE SYSTEM SUGGEST GROUND TEMPS
WILL BE WARM, WHICH COULD CUT DOWN ON THE ACCUMULATIONS. THE LATEST
PROBABILISTIC NBM HAS A 50-80% CHANCE OF 1" OF SNOW ALONG AND
NORTHWEST OF I-55. THE PROBABILITY OF 4" OF SNOW IS MAINLY FOCUSED
NORTH OF OUR CWA, BUT THERE IS A 15-40% CHANCE ROUGHLY NORTH OF A
MACOMB TO PONTIAC LINE.
MUCH COLDER CONDITIONS CAN BE EXPECTED SUN NIGHT THROUGH TUES,
WITH HIGHS IN THE MID 20S TO LOW 30S AND LOWS MON NIGHT IN THE
SINGLE DIGITS TO LOW TEENS. COMBINED WITH THE STRONG WINDS SUN
NIGHT INTO MON, THERE IS A 20-50% CHANCE FOR WIND CHILLS BELOW
ZERO NORTHWEST OF I-55 (HIGHEST NORTHWEST OF THE IL RIVER). FOR
MON NIGHT INTO TUES, THE PROBABILITY OF WIND CHILLS BELOW ZERO IS
30-60% ALONG AND NORTH OF I-70.
THE COLD APPEARS RELATIVELY SHORT-LIVED, WITH ENSEMBLE GUIDANCE
STRONGLY FAVORING A WARMING TREND DURING THE LATTER PART OF NEXT
WEEK.
ERWIN
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 441 AM CDT THU MAR 12 2026
LIGHT, WESTERLY WINDS TO START THE PERIOD WILL TURN TO
SOUTHWESTERLY AROUND 10-15 KTS BY MIDDAY. MID-LEVEL CLOUD SHIELD
MOVES IN FROM WEST TO EAST THIS AFTERNOON AND PERSISTS INTO THE
OVERNIGHT. WINDS AND GUSTS WILL BECOME MUCH STRONGER OVERNIGHT.
FOR NOW, HAVE GUSTS AROUND 30 KTS IN THE TAF, BUT PEAK GUSTS COULD
BE AS HIGH AS 40 KTS. LLWS IS A CONCERN OVERNIGHT, AS 2 KFT WINDS
APPROACH 55-60 KTS. THERE A CHANCE OF LIGHT RAIN SHOWERS AT
KPIA/KBMI THIS EVENING INTO THE OVERNIGHT, BUT WASN'T CONFIDENT
ENOUGH TO INCLUDE IN THE TAF.
ERWIN
ILX WATCHES/WARNINGS/ADVISORIES
WIND ADVISORY FROM 10 PM THIS EVENING TO 1 PM CDT FRIDAY FOR
ILZ027>031-036>038-040>057-061>063.
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