820
FXUS63 KIWX 040820
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
320 AM 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 /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1230 AM EST WED FEB 4 2026
IN THE MIDDLE OF THIS MID LEVEL TROUGH WITH PLENTY OF VORTICITY, AN
AREA OF SURFACE HIGH PRESSURE MOVES THROUGH TONIGHT, WHICH WOULD
SIGNIFY DRIER AIR. THE PROBLEM IS THAT THERE IS A THIN LAYER OF LOW
LEVEL MOISTURE IDENTIFIABLE IN RAP TIME SECTIONS THAT IS TRAPPED
UNDER THE INVERSION AND IS CONTRIBUTING TO STRATUS CLOUDS OVERHEAD.
MODELS HAVE BEEN INDICATING THAT THE AREA OF 925 MB MOISTURE WOULD
BE DRYING OUT BY NOW, BUT THAT HASN'T BEEN THE CASE SO WILL CONTINUE
TO HOLD ONTO IT USING A TEMPO GROUP FOR THESE FIRST 4 HOURS. THERE
IS ALSO DISAGREEMENT IN MODELS ABOUT WHAT TO DO WITH THE REST OF THE
DAY. DO WE CLOUD UP THE AFTERNOON (NAM/RAP) OR DO WE BREAK IT ALL UP
(LAV)? THERE ARE ALSO SOME LAKE ENHANCED SNOW SHOWERS AROUND IN MI
THAT MAY BE ABLE TO CREATE SOME SNOW AT SBN DURING THE FIRST 9 HOURS
OF THIS TAF PERIOD, BUT BELIEVE IT TO BE WEAK ENOUGH THAT IT CAN BE
LEFT OUT OF THESE TAFS.
A SLIGHT EASTERLY (OF NORTH) COMPONENT OF WIND MAY BE ENOUGH TO
KEEP CLOUDS SOCKED IN THROUGH MUCH OF THIS TAF PERIOD, BUT THAT
LOOKS TO BACK NORTHERLY AND NORTHWESTERLY THIS AFTERNOON AND
EVENING, WHICH WOULD INDICATE THAT IT MAY TAKE UNTIL LATER
WEDNESDAY TO FINALLY SCATTER OUT. BUT EVEN THAT MAY BE DELAYED
WITH FUTURE MODEL ADJUSTMENTS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...AGD
AVIATION...ROLLER
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page