569
FXUS63 KLOT 161723
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
1123 AM CST FRI JAN 16 2026
KEY MESSAGES
- A SHORT PERIOD OF SNOW THIS MORNING AND SCATTERED GUSTY SNOW
SHOWERS LATE THIS AFTERNOON INTO THIS EVENING, MAY BOTH BRING
HAZARDOUS TRAVEL CONDITIONS.
- TWO CLIPPER SYSTEMS WILL BRING A CHANCE (20-40%) OF SNOW TO
THE AREA SATURDAY AFTERNOON/EVENING AND SUNDAY AFTERNOON/
EVENING.
- BITTERLY COLD CONDITIONS ARE EXPECTED SUNDAY NIGHT THROUGH
TUESDAY MORNING WITH WIND CHILLS 15 BELOW TO 20 BELOW ZERO
POSSIBLE MONDAY MORNING.
DISCUSSION
ISSUED AT 232 AM CST FRI JAN 16 2026
AN UPPER LOW WILL SLOWLY PINWHEEL ACROSS THE GREAT LAKES REGION
INTO THIS WEEKEND WITH VARIOUS WAVES MOVING ACROSS THE AREA. THE
NEXT OF WHICH WILL BE A SHORT PERIOD OF SNOW CURRENTLY MOVING
ACROSS WI INTO EASTERN IA. THIS WILL MOVE ACROSS THE LOCAL AREA
DURING THE MORNING HOURS WHEN TEMPERATURES ARE STILL EXPECTED TO
BE BELOW FREEZING. AREAS ALONG/NORTH OF I-80 ARE MOST FAVORED
AND WHILE SNOW AMOUNTS WILL GENERALLY BE BELOW AN INCH, THERE
MAY BE SOME ISOLATED HIGHER AMOUNTS, WITH AREAS SOUTH OF I-80
PERHAPS ONLY SEEING A DUSTING.
AS THIS PRECIP SHIFTS EAST LATE IN THE MORNING, A BRIEF LULL IS
EXPECTED INTO EARLY/MID AFTERNOON WHEN TEMPERATURES ARE
EXPECTED TO WARM INTO THE MID 30S FOR MOST OF THE AREA. A STRONG
COLD FRONT WILL THEN MOVE ACROSS THE AREA THIS EVENING WITH
SCATTERED SNOW SHOWERS EXPECTED ALONG/AHEAD OF THIS FRONT.
STILL SOME UNCERTAINTY FOR BOTH HOW STRONG THESE SNOW SHOWERS
WILL BE (AND WHETHER THEY ARE SNOW SQUALLS) AND FOR COVERAGE.
FOR NOW HAVE CAPPED POPS IN THE CHANCE RANGE, BUT AS TRENDS
EMERGE, POPS MAY NEED TO BE INCREASED. SNOW AMOUNTS WITH THIS
ACTIVITY WILL BE CHALLENGING WITH PERHAPS NARROW SWATHS OF SNOW
AMOUNTS TO AN INCH WITH MOST AREAS ONLY SEEING TRACE/DUSTING.
COULD BE SOME FLURRIES TONIGHT INTO EARLY SATURDAY MORNING.
THERE IS GENERAL AGREEMENT FOR A WAVE TO MOVE ACROSS THE AREA
SATURDAY AFTERNOON/EVENING AND A SECOND WAVE SUNDAY AFTERNOON/
EVENING. THOUGH THERE IS STILL UNCERTAINTY FOR HOW STRONG THESE
WILL BE, HOW FAR SOUTH THEY WILL MOVE, HOW MUCH MOISTURE WILL BE
AVAILABLE AND THUS HOW MUCH SNOW MAY DEVELOP. HOWEVER, LOW
CHANCE POPS ALONG/NORTH OF I-80 SEEM REASONABLE FOR BOTH OF
THESE TIME PERIODS FOR NOW, BUT HIGHER POPS MAY BE NEEDED AS
TRENDS BECOME MORE CLEAR.
THE MAIN SURGE OF COLDER AIR THEN ARRIVES SUNDAY NIGHT AND THERE
COULD BE ANOTHER PERIOD OF SNOW SHOWERS ON THE LEADING EDGE OF
THIS ARCTIC FRONT. GIVEN THE PROXIMITY OF THE UPPER LOW AND
PERHAPS ANY ADDITIONAL WAVES THAT MAY BE MOVING ACROSS THE AREA,
THERE IS UNCERTAINTY FOR TEMPS/CLOUD COVER SUNDAY NIGHT INTO
MONDAY MORNING. BUT AS THE BLENDED GUIDANCE CURRENTLY STANDS,
LOW TEMPS IN THE LOW SINGLE DIGITS AND WINDS IN THE 15-25 MPH
RANGE WOULD PUSH WIND CHILLS INTO THE 15 BELOW TO 20 BELOW ZERO
RANGE FOR MONDAY MORNING. HIGH TEMPS ONLY REBOUND TO THE UPPER
SINGLE DIGITS/LOW TEENS MONDAY AND THEN LOWS AGAIN IN THE LOW
SINGLE DIGITS BY TUESDAY MORNING.
THERE HAS ALSO BEEN SOME AGREEMENT IN THE MODELS AND THEIR
ENSEMBLES FOR A CLIPPER SYSTEM TO BE MOVING ACROSS THE GREAT
LAKES REGION TUESDAY NIGHT INTO WEDNESDAY, PERHAPS MAINLY NORTH
OF THE LOCAL AREA. TOO FAR OUT FOR ANY SPECIFICS, BUT WILL NEED
TO BE MONITORED FOR ANOTHER POSSIBLE PERIOD OF SNOW. CMS
AVIATION /18Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 1123 AM CST FRI JAN 16 2026
A COOLING LOW-LEVEL TEMPERATURE PROFILE ATOP THE WARMING
BOUNDARY LAYER AHEAD OF A 700MB VORT/SPEED WAVE WILL PROMOTE
THE REDEVELOPMENT OF SNOW SHOWERS ACROSS THE AIRSPACE THIS
AFTERNOON. WITH THE CONVECTIVE LAYER FORECASTED TO EXTEND AS
HIGH AS MINUS 15C, THE MOST VIGOROUS SHOWERS MAY BE CAPABLE OF
PRODUCING GRAUPEL (SOFT HAIL), WESTERLY WIND GUSTS IN EXCESS OF
30 KT, AND EVEN A LIGHTNING STRIKE. SO, WILL MAINTAIN THE
INHERITED TEMPO GROUPS FOCUSING ON THE LATE AFTERNOON/EARLY
EVENING TIME PERIOD (GENERALLY 22-02Z) FOR BRIEF BUT STARK
VISIBILITY REDUCTIONS (1 MILE OR LESS) IN SNOW.
COVERAGE OF SNOW SHOWERS SHOULD TAPER PRIOR TO MIDNIGHT.
ATTENTION THEN TURNS TOWARD AN UPPER-LEVEL WAVE EMBEDDED WITHIN
BROAD UPPER-LEVEL CYCLONIC FLOW DUE TO SWING OVER THE AIRSPACE
TOMORROW. AM NOTING AN INCREASING SIGNAL FOR THE CORE OF THE
WAVE TO PASS DIRECTLY OVER THE AIRSPACE DURING THE AFTERNOON
HOURS (NEAR OR JUST AFTER THE END OF THE 24 HOUR TAF WINDOW FOR
MOST SITES). WITH A CONTINUED COLD TEMPERATURE PROFILE WITH A
DEEP LAYER OF SATURATION WITHIN A LOW-CENTROID DGZ, AM GROWING
INCREASINGLY CONCERNED FOR THE DEVELOPMENT OF WIDESPREAD AND STEADY
FLUFFY SNOW ACROSS THE AIRSPACE WITH PREVAILING LIFR TO IFR
VISIBILITY. WILL GO AHEAD AND INTRODUCE P6SM -SN (FOR FLURRIES)
AS EARLY AS DAYBREAK AT ALL TERMINALS, AND THEN 3SM -SN TOWARD
THE END OF THE 24 TO 30-HOUR TAF WINDOW FOR RFD/ORD/MDW. IF SUCH
A SIGNAL CONTINUES GOING FORWARD, LOWER VISIBILITY (1 TO 2
MILES, IF NOT PERIODICALLY 1/2 TO 3/4SM) WILL NEED TO BE
INTRODUCED INTO THE TAFS.
WINDS WILL REMAIN WESTERLY AND PERIODS OF MVFR CIGS WILL
PREVAIL THROUGH MUCH OF THE TAF PERIOD.
BORCHARDT
HYDROLOGY
ISSUED AT 1209 PM CST THU JAN 15 2026
THE UPCOMING EXTENDED PERIOD OF VERY COLD TEMPERATURES WILL LIKELY
RESULT IN THE RAPID DEVELOPMENT OF ICE ON AREA RIVERS AND STREAMS
WHICH MAY INCREASE THE CHANCE OF LOCALIZED ICE JAM FLOODING. LAST
WEEK'S HEAVY RAINFALL HAS RESULTED IN INCREASED STREAMFLOW IN
SEVERAL BASINS, INCLUDING THE FOX, DES PLAINS, AND ILLINOIS RIVER
BASINS. THIS HIGHER STREAMFLOW WILL RESULT IN A GREATER POTENTIAL
FOR FREEZE UP ICE JAM FLOODING.
- IZZI
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE IL
AND IN NEARSHORE WATERS.
VISIT US AT WEATHER.GOV/CHICAGO
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