114
FXUS63 KIWX 160527
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1227 AM EST FRI JAN 16 2026
KEY MESSAGES
- THE NEXT SYSTEM WILL BRING LIGHT SNOW ACCUMULATIONS OF AROUND
AN INCH LATE TONIGHT, WITH AN ADDITIONAL INCH OF SNOW POSSIBLE
ON FRIDAY. SLIGHTLY HIGHER AMOUNTS OF 2 TO 3 INCHES POSSIBLE
DURING THIS PERIOD NORTH OF THE TOLL ROAD ACROSS FAR NORTHERN
INDIANA AND SOUTHERN LOWER MICHIGAN.
- AFTER NEAR NORMAL HIGHS ON FRIDAY IN THE LOW TO MID 30S, A
TREND TO MUCH COLDER CONDITIONS IS IN STORE FOR THE WEEKEND
INTO EARLY NEXT WEEK WITH SUB-ZERO WIND CHILLS AT TIMES. THE
COLDEST CONDITIONS ARE EXPECTED FROM SUNDAY NIGHT THROUGH
TUESDAY.
- ADDITIONAL CHANCES OF LAKE EFFECT SNOW SHOWERS FOR THE WEEKEND
INTO EARLY NEXT WEEKEND, ESPECIALLY ACROSS SOUTHERN LOWER
MICHIGAN.
DISCUSSION
ISSUED AT 325 PM EST THU JAN 15 2026
LAKE EFFECT SHOWERS HAVE BECOME MORE CELLULAR IN NATURE OVER
THE LAST SEVERAL HOURS AND SHOULD CONTINUE TO DIMINISH THROUGH
EARLY EVENING AS INVERSION HEIGHTS LOWER IN RESPONSE TO
DEPARTURE OF COLD CORE UPPER LOW. ANOTHER UPPER LEVEL WAVE
DIGGING ACROSS THE DAKOTAS THIS AFTERNOON WILL SLIDE SOUTHEAST
ACROSS MINNESOTA LATER THIS EVENING AND WILL INDUCE A BROAD AREA
OF WEAK ISENTROPIC UPGLIDE ACROSS THE OHIO VALLEY AND SOUTHERN
GREAT LAKES TONIGHT. GIVEN DRYING NATURE TO LOW/MID LEVEL
AIRMASS INITIALLY THIS EVENING, SOME TOP-DOWN SATURATION
PROCESSES WILL NEED TO OCCUR BEFORE LIGHT SNOW IS REALIZED, BUT
OVERALL LITTLE CHANGE IN FORECAST THINKING IN BETTER CHANCES OF
ADDITIONAL LIGHT SNOW LATE TONIGHT INTO FRIDAY MORNING.
WHILE WARM ADVECTION WANES LATER FRIDAY MORNING, LAGGING BETTER
MID/UPPER LEVEL SYNOPTIC SUPPORT WITH THE DAKOTAS WAVE SHOULD
PROVIDE SOME ADDITIONAL LIGHT SNOW LATE FRIDAY MORNING INTO EARLY
AFTERNOON WITH AN ADDITIONAL INCH OF ACCUMULATION. SOME LAKE
ENHANCEMENT IS POSSIBLE ACROSS SW LOWER MICHIGAN AS WINDS BECOME
WEST-SOUTHWEST. SOME INCREASE IN SOUTHWEST WINDS IS ALSO EXPECTED ON
THURSDAY WITH SOME GUSTS TO 20 TO 25 MPH. THESE WINDS COULD LEAD
SOME BLOWING AND DRIFTING SNOW, PARTICULARLY FOR AREAS WHICH HAVE
RECEIVED THE RECENT HEAVY LAKE EFFECT SNOW. THIS INITIAL UPPER WAVE
SHOULD DEPART EARLY FRIDAY AFTERNOON, WITH MAIN QUESTION FOR
REMAINDER OF THE DAY ON ANY CONVECTIVE-TYPE SNOW SHOWERS
REDEVELOPING. SOME DIFFERENTIAL TEMPERATURE ADVECTION COULD INDUCE
SOME WEAK SURFACE-BASED INSTABILITY FOR AN ISOLATED-SCATTERED
SNOW SHOWER POTENTIAL DURING THE LATER AFTERNOON HOURS.
CONFIDENCE IN COVERAGE IS LOW GIVEN LOCAL AREA SHOULD BE
POSITIONED BETWEEN DEPARTING SHORT WAVE AND UPSTREAM UPPER LOW.
A RENEWED PUSH OF LOW LEVEL COLD ADVECTION WILL FOLLOW FOR FRIDAY
NIGHT AS THIS UPPER LEVEL LOW PUSHES ACROSS THE MID MS VALLEY. A
MORE DYNAMIC UPPER LEVEL SHORT WAVE IS STILL EXPECTED TO DIG ACROSS
SOUTHERN MO/KY FRIDAY NIGHT, WITH BEST LOW LEVEL LEVEL MOISTURE MORE
SUPPRESSED SOUTH OF THE LOCAL AREA BY THIS TIME. STRONG LOW LEVEL
COLD ADVECTION ACROSS THE LOCAL AREA MAY BE ACCOMPANIED BY SOME
ADDITIONAL SCATTERED SNOW SHOWERS. THE CURRENT EXPECTATION IS THAT
THESE SNOW SHOWERS WILL NOT EXHIBIT MUCH ORGANIZATION GIVEN
SOUTHWARD DISPLACEMENT OF STRONGER FORCING/MOISTURE, AND THE FACT
THAT LOW/MID LEVEL WIND FIELDS ARE ONLY WEAKLY FRONTOGENETIC IN
NATURE. SOME LIGHT ADDITIONAL SNOW ACCUMULATIONS ARE POSSIBLE (LESS
THAN AN INCH) FRIDAY NIGHT, AND MAINLY DOWNWIND OF LAKE MICHIGAN
DUE TO LAKE ENHANCEMENT. THE ADVECTION OF THIS MUCH COLDER AIRMASS
SHOULD RESULT IN WIND CHILLS DROPPING TO THE SINGLE DIGITS ABOVE
ZERO SATURDAY MORNING.
OVERALL, NOT MUCH CHANGE IN FORECAST THINKING FOR THE REMAINDER OF
THE PERIOD. A LARGE NEGATIVE UPPER HEIGHT ANOMALY WILL PERSIST
ACROSS THE GREAT LAKES THROUGH THE WEEKEND, WITH ADDITIONAL UPSTREAM
SHORT WAVES LIKELY TAKING A FAVORABLE TRACK INTO THE LOCAL AREA DUE
TO POSITIONING OF EASTERN PACIFIC LONGWAVE RIDGING. THIS PATTERN
WILL PROVIDE PERIODIC CHANCES OF ADDITIONAL SNOW SHOWERS, AND
REINFORCING SHOTS OF COLD AIR ADVECTION. CONDITIONS MAY NUDGE UP
AGAINST WIND CHILL ADVISORY LEVELS, PARTICULARLY MONDAY NIGHT INTO
TUESDAY MORNING WHICH LOOKS TO BE THE COLDEST PERIOD OF THE LONG
TERM AS A STRONG LOW LEVEL THERMAL TROUGH DROPS INTO THE REGION.
MEDIUM RANGE GUIDANCE DOES HINT AT ANOTHER CLIPPER-TYPE SYSTEM
FOR THE MIDDLE OF NEXT WEEK, FOLLOWED BY A TENDENCY TO LARGE
SCALE FLOW DEAMPLIFICATION THAT WOULD PROVIDE A SLOW MODERATING
TREND TOWARD END OF THIS FORECAST VALID PERIOD.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1227 AM EST FRI JAN 16 2026
A CLIPPER SYSTEM WILL BRING TWO ROUNDS OF LIGHT SNOW TO THE
TERMINALS LATER TODAY. THE FIRST WILL BE WITH THE INITIAL
THETA-E SURGE ROUGHLY 08-11Z AND THEN THE MAIN SHORTWAVE/COLD
FRONT DURING THE EARLY AFTERNOON. THE FIRST ROUND IS MUCH WEAKER
AND EXPECT ONLY BRIEF MVFR CONDITIONS. THE SECOND ROUND WILL BE
STRONGER AND SOME IFR CONDITIONS ARE LIKELY, ESPECIALLY AT KSBN.
THE DURATION OF SNOW WILL BE RELATIVELY SHORT THOUGH.
POSTFRONTAL CAA LEADS TO A PERIOD OF FUEL-ALTERNATE CEILINGS BUT
SOME MINOR IMPROVEMENT IS EXPECTED BY THE LATE EVENING BEFORE
ANOTHER SHORTWAVE ARRIVES EARLY SAT MORNING.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-
046.
DISCUSSION...MARSILI
AVIATION...AGD
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