866
FXUS63 KIWX 030003
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
703 PM EST MON FEB 2 2026
KEY MESSAGES
- LIGHT PATCHY FREEZING DRIZZLE OR FLURRIES POSSIBLE THROUGH EARLY
EVENING.
- A BAND OF LIGHT SNOW MAY AFFECT AREAS ROUGHLY ALONG AND SOUTH
OF US ROUTE 30 LATE TONIGHT. ANY SNOW ACCUMULATIONS ARE
EXPECTED TO BE LESS THAN AN INCH. CONFIDENCE REMAINS LOW ON
SNOW ACCUMULATION OCCURRENCE TONIGHT AND THE EXACT PLACEMENT
OF THIS POTENTIAL.
- HIGH TEMPERATURES MODERATE THURSDAY AND FRIDAY BEFORE ANOTHER BRIEF
SHOT OF ARCTIC AIR FOR THE WEEKEND LATE FRIDAY/EARLY WEEKEND.
- SOME LIGHT SNOW ACCUMULATIONS POSSIBLE LATE THURSDAY INTO
FRIDAY.
DISCUSSION
ISSUED AT 246 PM EST MON FEB 2 2026
SOME LINGERING LIGHT DRIZZLE/FLURRIES PERSIST THIS AFTERNOON,
PARTICULARLY ACROSS SOUTHWEST LOWER MICHIGAN AND FAR NORTHWEST
INDIANA WHERE SOME WEAK WARM ADVECTION INDUCED LIFT IS
OCCURRING. OVER THE PAST FEW HOURS, SOME INCREASE IN MIXED
LAYER DEPTH APPEARS TO BE FAVORING THERMAL PROFILES JUST COLD
ENOUGH TO SUPPORT ICE NUCLEATION WITH INCREASED FLURRIES REPORTS
FOR PRECIP TYPES ACROSS NW INDIANA/SW LOWER MICHIGAN. IN
ADDITION, NEAR TERM MODEL TIME/HEIGHT AND CROSS SECTIONS HAVE
INDICATED SOME DESCENDING MID LEVEL DRY AIR THAT WILL ALSO LIMIT
PRECIP PRODUCTION EFFICIENCY. GIVEN THE ABOVE, AND LESS IMPACTS
BEING REPORTED OVER PAST FEW HOURS, WILL LIKELY BE ABLE TO
CANCEL THE WINTER WEATHER ADVISORY AREA EARLY FOR PORTIONS OF
THE WINTER WEATHER ADVISORY.
SOME FLURRIES LIKELY TO CONTINUE INTO THIS EVENING AS SOME CONTINUED
WEAK ISENTROPIC LIFT SHIFTS EAST. THIS WEAK SHALLOW LIFT WILL BE IN
ADVANCE OF A COLD FRONT SHIFTING SOUTHEAST ACROSS THE SOUTHERN
GREAT LAKES. THIS COMBINATION SHOULD ALLOW FOR SOME
STRENGTHENING LOW LEVEL BAROCLINICITY ACROSS THE REGION. PRECIP
PROSPECTS AFTER 00Z COULD BE LIMITED BY THE EXTENT OF LOW LEVEL
DRY AIR ADVECTION SHIFTING ACROSS THE SOUTHERN GREAT LAKES.
LOOKING UPSTREAM, MID/UPPER LEVEL SHORT WAVE FORCING LOOKS TO
COME IN A COUPLE OF DISJOINTED PORTIONS OVERNIGHT INTO EARLY
TUESDAY. THE FIRST WAVE IS THE SOUTHERN PERIPHERY OF STRONGER
UPPER LOW WORKING ACROSS SOUTH CENTRAL CANADA AND A GLANCING
BLOW ACROSS SOUTHERN LOWER MICHIGAN OF SOME BETTER VORTICITY
ADVECTION. THE SECOND WAVE APPEARS TO BE A SLIGHTLY MORE DELAYED
POSITIVELY TILTED UPPER TROUGH THAT SHIFTS ACROSS THE CORN BELT
LATE TONIGHT. BOTH OF THESE FEATURES WILL LIKELY HAVE SOME
ENHANCED DOWNSTREAM LOW-MID LEVEL BAROCLINICITY ASSOCIATED WITH
THEM, PARTICULARLY THIS MORE SOUTHERLY WAVE WHICH HAS A BETTER
CHANCE OF STRONGER FGEN FORCING.
HREF PROBS STILL SUGGEST BEST CHANCE OF MEASURABLE SNOW OVERNIGHT
GENERALLY SOUTH OF US 30 IN A NARROW CORRIDOR. PREDICTABILITY
RESOLVING EXACT LOCATIONS OF THESE NARROW FGEN BANDS IS QUITE
CHALLENGING, EVEN AT A 6 TO 12 HOUR FORECAST DISTANCE. FOR THE
AFTERNOON PACKAGE, DID NUDGE UP POPS SLIGHTLY ACROSS THE SOUTH TO
ACCOUNT FOR THIS POTENTIAL BUT ADDITIONAL REFINEMENTS WILL BE
NEEDED. LOCATIONS ACROSS THE SOUTH ALSO HAVE THE BEST CHANCE OF
WESTERLY FLOW ADVECTING IN DEEPER MOISTURE PROFILES FOR A VERY BRIEF
TIME. ACROSS THE NORTH, WILL LIKELY MAINTAIN SLIGHT CHANCE
POPS/FLURRIES WITH FORECAST SOUNDINGS DEPICTING MARGINAL
SATURATION AT LOWER DEPTHS OF DGZ. IT IS POSSIBLE SOME SEEDER-
FEEDER PROCESSES COULD PROMOTE FLURRIES/PATCHY LIGHT SNOW ACROSS
THE NORTH HOWEVER. CANNOT COMPLETELY RULE OUT THE NEED FOR MORE
PATCHY DRIZZLE MENTION ON NORTHERN PERIPHERY OF THIS FORCING
TONIGHT GIVEN MARGINAL MOISTURE PROFILES FOR THESE LOCATIONS.
THE SLOW ARRIVAL OF THE UPSTREAM POSITIVELY TILTED WAVE SHOULD
MAKE MAIN PERIOD OF BETTER LIGHT SNOW CHANCES FROM 09Z-15Z, WITH
THESE FORCING MECHANISMS SHIFTING SOUTH BY LATE TUESDAY
MORNING. SOME WEAK LAKE RESPONSE IS POSSIBLE LATE
TONIGHT/TUESDAY BUT OVERALL WEAK NATURE TO FLOW MAY MAKE THIS
MORE OF A MID-LAKE CONVERGENCE FORCING.
LOW LEVEL COLD ADVECTION CONTINUES BEHIND THIS UPPER TROUGH TUESDAY
NIGHT/WEDNESDAY, WITH WEDNESDAY LOOKING LIKE THE COLDEST DAY OF THE
WORK WEEK. THE NEXT CANADIAN SHORT WAVE TROUGH IS EXPECTED TO DAMPEN
THE WESTERN CONUS/CANADIAN UPPER RIDGE ENOUGH TO ALLOW FOR SOME
MODERATION IN TEMPS THURSDAY/FRIDAY (LOW-MID 30S FRIDAY). A JET
INDUCED SMALL SCALE WAVE IS EXPECTED TO DIVE SOUTHEAST FROM THIS
PARENT LOW ACROSS THE GREAT LAKES REGION ON THURSDAY. MOISTURE
LIMITATIONS SHOULD LIMIT PRECIP POTENTIAL IN WARM ADVECTION
PHASE PRECEDING THIS SYSTEM, WITH HIGH CHANCE POPS/LOW LIKELY
POPS LATE THURSDAY NIGHT INTO FRIDAY ASSOCIATED WITH FRONTAL
FORCING. THIS SYSTEM LOOKS POTENTIALLY LIKE ANOTHER CASE WHERE
DEEPER MOISTURE PROFILES INTO THE DGZ ARE SOMEWHAT LIMITED IN
DURATION, SUGGESTING ONLY LIGHT SNOW ACCUMULATIONS AT THIS TIME.
A PERIOD OF COLDER TEMPERATURES WITH SINGLE DIGIT ABOVE TO SUB-ZERO
WIND CHILLS IS EXPECTED FRIDAY NIGHT INTO SATURDAY. THE LAKE EFFECT
POTENTIAL BEHIND THIS SYSTEM COULD ALSO BE HAMPERED BY LIMITED
MID LEVEL MOISTURE DEPTHS FOR ANY SIGNIFICANT DURATION. MEDIUM
RANGE GUIDANCE DOES POINT TO CONSENSUS IDEA OF A PATTERN SHIFT
EARLY NEXT WEEK THAT WOULD FINALLY ALLOW SOME WEST COAST
LONGWAVE TROUGHING AND AT LEAST A PERIOD OF WARMER TEMPS NEXT
WEEK.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 649 PM EST MON FEB 2 2026
EXPECT MVFR TO VFR CONDITIONS THROUGH THE PERIOD. AREAS OF LIGHT
SNOW AND/OR FREEZING DRIZZLE ARE MOVING THROUGH NORTHERN
INDIANA, WITH DRY AIR INFILTRATING FROM THE WEST-NORTHWEST AS A
COLD FRONT MOVES THROUGH. SNOW AS OF THIS WRITING HAS TAPERED
OFF AT KSBN, WITH KEKM/KPPO STILL REPORTING UNKNOWN P-TYPE
(LIKELY VERY LIGHT FREEZING DRIZZLE) OR SNOW. KFWA SHOULD SEE
SNOW POTENTIAL TAPER OFF LATER THIS EVENING, WITH A PLUME OF
FACTORY INDUCED MOISTURE STREAMING FROM AROUND GARY, IN AND ALSO
JUST NORTH OF KFWA KEEPING THE DRY AIR FROM TAKING OVER
COMPLETELY. A PLUME OF LIGHT SNOW/FREEZING DRIZZLE EXTENDS FROM
KPPO DOWN THROUGH KC65/KFWA INTO KVNW AS OF THIS WRITING, WITH
VISIBILITIES AND CEILINGS IN THE 2-3SM RANGE FURTHER NORTHWEST,
AND AROUND 6-10SM NEAR KFWA EASTWARD (EXCEPT KGWB AT 1/2SM WITH
SNOW AND FZFG). HAVE A TEMPO FOR KFWA TO ACCOUNT FOR THE
POTENTIAL DROP IN CEILINGS/VISIBILITIES WITH THE REMAINING SNOW
SHOWERS (KASW HAD 1500 FT, MOST OTHERS SOUTH AND WEST ARE IN
THE 2000-3500 FT RANGE)-WITH CEILINGS OF 2000FT AND VIS OF 4SM
(GIVEN KFWA IS FURTHER SOUTH CLOSER TO DRIER AIR). OUTSIDE OF
THAT, EXPECT CEILINGS TO HOVER AROUND THE MVFR/VFR THRESHOLD,
WITH A POTENTIAL PERIOD BEFORE THE NEXT SYSTEM OF 4-5KFT
CEILINGS LATE TONIGHT.
DRY AIR SHOULD TEMPORARILY TAKE OVER BEFORE THE NEXT CLIPPER SYSTEM
ARRIVES LATE TONIGHT/TUE AM-BUT THERE ARE SIGNIFICANT QUESTIONS
AS TO HOW FAR NORTH THE PRECIPITATION SHIELD WILL EXTEND. SOME
OF THE GUIDANCE KEEPS THE PRECIPITATION FAR SOUTH, OTHERS EXTEND
IT INTO KFWA WITH POTENTIAL FOR SOME LAKE ENHANCED SNOW SHOWERS
ON NORTH-NORTHWEST WINDS AFTER 18Z (LEFT OUT OF KSBN FOR NOW).
HAVE VCSH/-SHSN IN THE 12-21Z TIME AT KFWA FOR NOW.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...MARSILI
AVIATION...MCD
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