472
FXUS63 KIWX 041718
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1218 PM EST WED FEB 4 2026
KEY MESSAGES
- A FEW FLURRIES ARE POSSIBLE TODAY WITH HIGHS IN THE LOW/MID 20S.
- A DUSTING OF SNOW IS EXPECTED ON THURSDAY AFTERNOON WITH A 30
PERCENT CHANCE OF SOME FREEZING DRIZZLE THURSDAY EVENING.
- 1-2 INCHES OF SNOW IS EXPECTED FRIDAY MORNING WITH THE HIGHEST
AMOUNTS ALONG AND EAST OF I-69.
- AFTER A BRIEF WARMUP ON FRIDAY, MORE COLD WEATHER IS EXPECTED
SATURDAY.
DISCUSSION
ISSUED AT 320 AM EST WED FEB 4 2026
WEAK LOW LEVEL FRONT HAS CLEARED THE AREA WITH INCREASINGLY
NORTHERLY FLOW ADVECTING COLDER AIR BACK INTO THE CWA. APPEARS TO BE
JUST ENOUGH RESIDUAL BOUNDARY LAYER MOISTURE UNDER STRENGTHENING
SUBSIDENCE INVERSION AND THETA-E CONTRIBUTION FROM THE LAKES TO
MAINTAIN MOSTLY CLOUDY SKIES. FURTHER, STRATUS DECK SQUARELY
INTERSECTS DGZ SO WE ARE GETTING SOME FLURRIES ACROSS THE AREA, AND
EVEN SOME LIGHT INDUSTRIAL-ENHANCED SNOW. THIS ACTIVITY WILL LIKELY
CONTINUE THROUGH THE MORNING UNTIL A SHORTWAVE PASSES, LOW LEVEL
FLOW STARTS TO BACK, AND SOME BOUNDARY-LAYER WARMING STARTS TO OCCUR
THIS AFTERNOON. NO EVIDENCE OF A PROMINENT MIDLAKE BAND JUST YET BUT
RADARS MAY BE OVERSHOOTING IT. MOST HI-RES GUIDANCE CONTINUES TO
SUPPORT LAND BREEZE DEVELOPMENT IN LIGHT SYNOPTIC FLOW THAT WILL
DEVELOP A MODEST DOMINANT BAND IN THE MIDDLE OF THE LAKE BY LATE
MORNING. IF SO, THIS BAND WILL BE PUSHED INTO OUR NW COUNTIES LATER
THIS EVENING BY BACKING LOW LEVEL WINDS. MAINTAINED SOME LOW POP'S
TO ACCOUNT FOR THIS SCENARIO BUT BACKING FLOW IN AN ALREADY
UNFAVORABLE THERMODYNAMIC ENVIRONMENT WITH LOW INVERSION HEIGHTS WILL
ALSO SIGNIFICANTLY DISRUPT THE BAND AND LIMIT ACCUMULATION POTENTIAL
FOR OUR AREA. A TENTH OR TWO IS POSSIBLE IN BERRIEN, NORTHERN LA
PORTE, AND PERHAPS WESTERN ST. JOSEPH (IN) AROUND 00Z BUT NOT
EXPECTING ANY SUBSTANTIVE ACCUMULATION OR IMPACTS. STRATUS BLANKET
KEEPING MOST AREAS SIGNIFICANTLY WARMER THAN PREVIOUSLY EXPECTED BUT
CAA WILL STILL HOLD A LID ON TODAY'S HIGHS WITH GENERALLY LOW/MID
20S EXPECTED. RAISED TONIGHT'S LOWS AS WELL WITH THE EXPECTATION FOR
MORE STRATUS DEVELOPMENT OVERNIGHT (IF WE EVER EVEN BREAK OUT THIS
AFTERNOON).
PAIR OF MIDLEVEL SHORTWAVES THEN COME DIVING OUT OF THE CANADIAN
PRAIRIES THU AND FRI WITH OUR NEXT ROUND OF ACTIVE WEATHER. THE FIRST
WAVE ARRIVES THU AFTERNOON AND IS THE WEAKER OF THE TWO, BATTLING A
LOT OF DRY AIR/STABLE CONDITIONS. A BRIEF WINDOW (ONLY AROUND 3
HOURS FOR MOST) OF MODERATE ISENTROPIC UPGLIDE AMID A BROAD MIDLEVEL
TROUGH WILL SUPPORT LIGHT PRECIP FOR MUCH OF THE REGION BUT QPF WILL
BE LIMITED TO A FEW HUNDREDTHS YIELDING A HALF-INCH OR SO DURING THE
THU AFTERNOON COMMUTE. NO ICE NUCLEATION CONCERNS WITH THE INITIAL
PRECIP (ALL SNOW) BUT IT DOES BECOME A CONCERN THU EVENING. 00Z
NAM12 IS THE MOST CONCERNING WITH WIDESPREAD FREEZING DRIZZLE BUT
TYPICAL NAM LOW LEVEL MOISTURE ISSUES APPEAR TO ALSO BE AT PLAY.
OTHER (LOW-RES) GUIDANCE SHOWS DRIER PROFILES THU NIGHT WITH
LITTLE/NO PRECIP BUT NOT CONFIDENT IN THIS SCENARIO EITHER. HAVE
RAISED NBM POP'S AND QPF WITH A CHANCE OF FREEZING DRIZZLE
MENTIONED. CONFIDENCE IN THIS ASPECT OF THE FORECAST IS NOT HIGH,
THOUGH. SECOND WAVE THEN ARRIVES ON FRI. STILL SOME SIGNIFICANT
MODEL DIFFERENCES HERE AS WELL. MOST GUIDANCE AGREES ON SOME PRECIP
BUT DIFFERENCE IS IN AMOUNTS. HERE LEANED TOWARD WPC, ECMWF, AND
CANADIAN GUIDANCE WHICH HAS TENDED TO DO BETTER WITH THESE CANADIAN
CLIPPERS. A QUICK 1-2" IS LIKELY FOR OUR NE HALF WITH ISOLATED
AMOUNTS AROUND 3" CERTAINLY POSSIBLE, THOUGH MID 30S HIGHS WILL TAKE
A TOLL ON ACCUMULATION EFFICIENCY. SOME LAKE RESPONSE LIKELY FRI
NIGHT INTO EARLY SAT BUT IT'S TOO EARLY TO PIN DOWN LOCATIONS OR
AMOUNTS.
ANOTHER CLIPPER SYSTEM IS POSSIBLE EARLY SUNDAY BUT ENSEMBLE
GUIDANCE SHOWS VERY WIDE SPREAD ON TIMING AND TRACK. AFTER ONE
MORE COLD SPELL OVER THE WEEKEND, MORE NOTABLE WARMUP FINALLY
ARRIVES NEXT WEEK. THERE ARE SOME CHANCES FOR PRECIP BUT
GUIDANCE CONTINUE TO BE HIGHLY VARIABLE FOR THIS TIMEFRAME.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1218 PM EST WED FEB 4 2026
A MOISTURE-STARVED UPPER LEVEL TROUGH WILL TRACK ACROSS THE
SOUTHERN GREAT LAKES AND OHIO RIVER VALLEY INTO THIS EVENING.
SOME INCREASE IN MID LEVEL SUBSIDENCE INTO THIS EVENING IN THE
WAKE OF THIS WAVE SHOULD TEND TO ERODE LOW LEVEL CLOUDS. THE
CHANCES OF MVFR CIGS IN THE 2-3K FT RANGE WILL PERSIST TONIGHT
HOWEVER AS BACKING LOW LEVEL WINDS IN RESPONSE TO LOW LEVEL
ANTICYCLONE SINKING SOUTH ACROSS THE MID MS RVR VALLEY COULD
ALLOW FOR EASTWARD ADVANCEMENT OF WEAK LAKE AGGREGATE TROUGH.
MOISTURE DEPTHS AND INVERSION HEIGHTS WILL BE LIMITED SO
CURRENTLY NOT EXPECTING THIS TO BE MORE THAN PATCHY LIGHT
SNOW/FLURRIES. WARM ADVECTION INCREASES LATE TONIGHT INTO
THURSDAY IN ADVANCE OF WEAK NORTHWEST FLOW SHORT WAVE.
CONFIDENCE IN PRECIPITATION IS LOW IN THIS WARM ADVECTION PHASE
DUE TO MOISTURE LIMITATIONS, BUT BEST CHANCES OF LIGHT SNOW
THURSDAY MORNING APPEARS TO BE AT KSBN. GIVEN MOISTURE
LIMITATIONS, CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE PRECIP AT
THIS TIME WITH THE 18Z TAFS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...AGD
AVIATION...MARSILI
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