899
FXUS63 KIWX 031120
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
620 AM EST SAT JAN 3 2026
KEY MESSAGES
- TEMPERATURES REMAIN BELOW NORMAL THROUGH THE WEEKEND.
- SOME SCATTERED FLURRIES OR LIGHT SNOW SHOWERS POSSIBLE TODAY,
WITH ANOTHER BRIEF CHANCE OF LIGHT SNOW SUNDAY NIGHT. LITTLE
TO NO IMPACTS ARE EXPECTED THIS WEEKEND.
- A WARMING TREND BEINGS EARLY NEXT WEEK AND CONTINUES THROUGH LATE
WORK WEEK.
- BETTER CHANCES FOR RAIN RETURN THURSDAY.
DISCUSSION
ISSUED AT 242 AM EST SAT JAN 3 2026
LONGWAVE PATTERN THIS MORNING FEATURES A WESTERN CONUS RIDGE WITH AN
UPPER LEVEL TROUGH CENTERED ACROSS SE CANADA. THE LOCAL AREA IS
POSITIONED IN THE INFLECTION ZONE OF THIS LONGWAVE PATTERN WITH
SEVERAL DISTURBANCES RIPPLING THROUGH NORTHWEST FLOW FROM THE
CENTRAL/NORTHERN PLAINS INTO SOUTH CENTRAL CANADA. WHILE OVERALL
SYNOPTIC FORCING WILL BE WEAK WITH BROAD MID LEVEL TROUGH WORKING
ACROSS THE GREAT LAKES LATER TODAY, A RESPECTABLE 120 KNOT UPPER
STREAK IS EXPECTED TO DIVE SOUTHEAST THROUGH DOWNSTREAM PORTION OF
THE LONGWAVE RIDGE INTO THE WESTERN GREAT LAKES. LOW LEVEL MOISTURE
IS HIGHLY LACKING ACROSS THE REGION THIS MORNING, WITH KDTX RAOB
FROM LAST EVENING INDICATING A 0.13 PWAT. SOME LOW/MID LEVEL
MOISTURE RECOVERY IS NOTED HOWEVER LOOKING AT UPSTREAM LOW LEVEL
FLOW TRAJECTORIES AND KOAX RAOB FROM LAST EVENING WITH 2.5-3
G/KG MIXING RATIOS AT 850 MB. THIS LOW LEVEL DRY AIR WILL BE
STUBBORN TO ERODE TODAY GIVEN OVERALL WEAK NATURE OF SYNOPTIC
LIFT, BUT SOME ENHANCED MID LEVEL FRONTOGENESIS IS EXPECTED TO
DEVELOP FROM WESTERN WI INTO SOUTHERN LAKE MI LATER THIS
MORNING. THIS COULD ALLOW ENOUGH ICE NUCLEI SEEDING TO GET SOME
GENERATION OF FLURRIES OR LIGHT SNOW SHOWERS, PARTICULARLY
NORTHEAST HALF OF THE AREA LATER THIS MORNING INTO THIS
AFTERNOON. SNOW ACCUMULATIONS ARE NOT EXPECTED AT THIS TIME.
IN TERMS OF TEMPERATURES TODAY, LOW LEVELS HAVE MODERATED SOMEWHAT
OVER THE PAST 12 HOURS, BUT APPROACH OF THE UPSTREAM MID LEVEL
TROUGH WILL SUPPORT TRANSITION BACK TO WEAK LOW LEVEL CAA LATER THIS
MORNING INTO THIS AFTERNOON. DESPITE THIS COLD ADVECTION,
SLIGHTLY BETTER MIXING (ALTHOUGH STILL WEAK) WITH THIS CAA AND
HIGHER CLOUD BASES TODAY SHOULD SUPPORT AT LEAST A FEW DEGREES
OF WARMING IN COMPARISON TO YESTERDAY. ON THE OTHER SIDE OF THE
COIN, SOME WEAK EVAPORATIVE PROCESSES INTO THE LOW LEVEL DRY
LAYER WITH TOP-DOWN MOISTENING TODAY COULD MAKE REACHING THE 30
DEGREE MARK A STRUGGLE.
SOME RENEWED LOW LEVEL THERMAL TROUGHING ADVECTING BACK ACROSS THE
SOUTHERN GREAT LAKES THIS EVENING SHOULD PROMOTE SOME LAKE RESPONSE,
ALTHOUGH GOOD SURGE OF MID LEVEL DRY AIR ADVECTION BEHIND THIS
TROUGH SHOULD MAKE MOISTURE PROFILES QUITE MARGINAL IN SHALLOW BASED
SNOW PRODUCTION LAYER. OPTED TO KEEP SOME FLURRIES/SLIGHT CHANCE
POPS TO COVER THIS SCENARIO TONIGHT.
BELOW NORMAL TEMPERATURES CONTINUE INTO SUNDAY WITH ATTENTION
TURNING TO A SLIGHTLY MORE PROMINENT SHORT WAVE WHICH IS EXPECTED TO
RACE EASTWARD FROM CALIFORNIA TODAY INTO SUNDAY. GUIDANCE HAS BEEN
FAIRLY CONSISTENT IN DEPICTING A BRIEF BUT FAIRLY STRONG SHOT OF 280-
290K ISENTROPIC ASCENT WITH WARM-FRONTAL FEATURE ASSOCIATED WITH
THIS SHORT WAVE SUNDAY EVENING. CONDENSATION PRESSURE DEFICITS IN
THIS LAYER SUGGEST PRECIP INITIALLY ACROSS WI WITH THIS FORCING
WILL TRY TO DEVELOP SOUTHEAST INTO MI/FAR NORTHERN INDIANA
SUNDAY NIGHT, BUT MORE LIKELY ACROSS EXTREME NE IN/FAR NW
OHIO/SOUTH CENTRAL LOWER MICHIGAN. ISENTROPIC PROGS STILL A
SUGGEST A SHORT TEMPORAL WINDOW OF ABOUT 3 HOURS FOR ANY
MEASURABLE PRECIP BEFORE WARM LAYER MAKES RH MORE MARGINAL. SOME
VERY LOW PROBS COULD EXIST FOR BRIEF LIGHT SLEET OR FREEZING
RAIN GIVEN THERMO PROFILES, BUT CONFIDENCE REMAINS TOO LOW FOR
ANYTHING OTHER THAN LOW SNOW CHANCES AT THIS TIME.
NEXT WEEK WILL FEATURE MODERATING TEMPERATURES AS UPSTREAM RIDGE
DEAMPLIFIES AS IT SHIFTS EAST. THIS EVOLUTION SHOULD LAY OUT
WARM FRONTAL FEATURE FROM CORN BELT TO SOUTHERN GREAT LAKES
MONDAY INTO TUESDAY, WITH A POTENTIAL OF SOME
STRATUS/DRIZZLE/FOG. PARTICULARLY SOME TIME IN MONDAY NIGHT
THROUGH TUESDAY NIGHT PERIOD. AMPLIFYING LONGWAVE PATTERN TOWARD
END OF WORK WEEK SHOULD ALLOW FOR ADDITIONAL WARMING TO WELL
ABOVE NORMAL WITH INCREASED RAIN CHANCES AND PERHAPS A RUMBLE OF
THUNDER HEADING INTO THURSDAY. GUIDANCE CONTINUES TO WAFFLE ON
HOW TO BUDGET STRENGTHS OF NORTHERN/SOUTHERN STREAM, BUT GIVEN
LARGE SCALE SUPPORT HAVE ACCEPTED BLENDED GUIDANCE OF LOW LIKELY
RAIN POPS FOR THU. TEMPS SHOULD ALSO TREND BACK CLOSER TO
NORMAL IN WAKE OF THIS SYSTEM NEXT WEEKEND.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 616 AM EST SAT JAN 3 2026
CEILINGS ARE SLOWLY DECLINING THIS MORNING BUT WELL WITHIN VFR.
ABUNDANT DRY AIR FROM 900-700MB IS PREVENTING ANY HYDROMETEORS
FROM REACHING THE GROUND DESPITE INCREASING RADAR RETURNS OVER
THE AREA. CANNOT COMPLETELY RULE OUT 6SM FLURRIES LATER TODAY.
LATE TONIGHT, NORTHWEST FLOW OFF LAKE MICHIGAN AND A SHORTWAVE
PASSING THROUGH MICHIGAN LOOKS TO BRING A PERIOD OF MVFR
CEILINGS TO KSBN (50-60% PROBABILITY PER THE IN-HOUSE BLEND). AT
KFWA, THIS IS ONLY A 30% PROBABILITY.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...MARSILI
AVIATION...BROWN
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