054
FXUS63 KIWX 061131
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
631 AM EST TUE JAN 6 2026
KEY MESSAGES
- MUCH WARMER CONDITIONS THIS WEEK WITH HIGHS IN THE 50S EXPECTED
THURSDAY AND FRIDAY. TURNING COLDER FOR THIS WEEKEND.
- AREAS OF FOG AND DRIZZLE DEVELOP THIS MORNING. THE FOG MAY BE LOCALLY
DENSE FROM MID MORNING THROUGH EARLY AFTERNOON. FOG IS
EXPECTED TO LINGER TONIGHT, ESPECIALLY ACROSS NORTHEAST
INDIANA AND SOUTH CENTRAL LOWER MICHIGAN.
- RAIN SHOWERS (70-90%) ARE EXPECTED THURSDAY AND THURSDAY
NIGHT. CHANCES OF RAIN CONTINUE FRIDAY (40-50%), BUT RAIN
SHOWERS BECOME LIKELY AGAIN FRIDAY NIGHT.
- A CHANGEOVER FROM RAIN SHOWERS TO SNOW SHOWERS EXPECTED THIS
WEEKEND.
DISCUSSION
ISSUED AT 345 AM EST TUE JAN 6 2026
A WELL-DEFINED WARM FRONTAL BOUNDARY FROM CENTRAL ILLINOIS INTO
CENTRAL INDIANA WILL LIFT NORTHWARD THIS MORNING WITH SOME STRONG
LOW LEVEL MOISTURE TRANSPORT ACCOMPANYING THIS FEATURE. WATER VAPOR
IMAGERY EARLY THIS MORNING INDICATES A WELL DEFINED UPPER LEVEL
SHORT WAVE ACROSS EASTERN IOWA. NOT MUCH HAS CHANGED IN TERMS OF
FORECAST EXPECTATIONS THIS MORNING, ALTHOUGH COULD BE A BIT MORE
DELAYED WITH RAIN/DRIZZLE/FOG. APPROACH OF THIS SHORT WAVE AND
NORTHWARD TRANSPORT OF THIS MOISTURE SHOULD LEAD TO AN INCREASED
AREA OF NEAR SFC MOISTURE CONVERGENCE ACROSS NORTHEAST ILLINOIS
SHIFTING ACROSS NORTHERN INDIANA AFTER DAYBREAK. FOG IS
EXPECTED TO DEVELOP AFTER 12Z, WITH GREATEST POTENTIAL JUST TO
NORTH OF WARM FRONTAL BOUNDARY WHERE RESIDUAL STALLED SFC
BOUNDARY IS STILL CHARACTERIZED BY SURFACE TEMPS IN LOW-MID 30S.
THE FOG MAY BECOME LOCALLY DENSE FOR A TIME, PARTICULARLY IN
THE 15Z-20Z TIMEFRAME WITH MOST FAVORED AREAS OF DENSE FOG
ACROSS FAR NE INDIANA/SOUTH CENTRAL LOWER MI, AND FAR NORTHWEST
OH. SOME FAIRLY DEEP LIFT IS EXPECTED FOR AT A LEAST A SHORT
TIME THROUGH MID MORNING WITH APPROACH OF EASTERN IA SHORT
WAVE, BUT MOISTURE DEPTHS WILL BE LIMITED. A COMBINATION OF
LIGHT RAIN/PATCHY DRIZZLE SHOULD ACCOMPANY THIS SHORT WAVE WITH
DRIZZLE PTYPE MORE LIKELY SOUTHWEST HALF OF THE FORECAST AREA
MORE DIVORCED FROM STRONGER SYNOPTIC FORCING AND WHERE A MID
LEVEL DRY SLOT PUSHES THROUGH THIS MORNING. OTHERWISE, TEMPS
SHOULD CONTINUE TO MODERATE TODAY, ALTHOUGH CLOUDS/FOG/DRIZZLE
WILL LIMIT THIS POTENTIAL SOMEWHAT WITH HIGHS FROM AROUND 40 FAR
NORTH TO UPPER 40S FAR SOUTH.
A LAGGING WEAK MID LEVEL TROUGH WILL KEEP SOME WEAK LOW LEVEL
TROUGHINESS IN PLACE TONIGHT. APPROACH OF THIS TROUGH AND WEAK LOW
LEVEL SUBSIDENCE/SUBSIDENCE INVERSION KEEPING MOISTURE TRAPPED
IN PLACE SUGGEST SCENARIO OF MAINTENANCE OF STRATUS/FOG/PATCHY
DRIZZLE TONIGHT WITH GREATEST COVERAGE AGAIN ACROSS THE
NORTHEAST. IT STILL APPEARS AS THOUGH WEDNESDAY SHOULD FEATURE
GREATER POTENTIAL OF AT LEAST PARTIAL CLEARING FROM SOUTHWEST-
NORTHEAST AS DRIER SOUTHWEST FLOW TAKES SHAPE ON NORTHWEST
PERIPHERY OF RETREATING ANTICYCLONE. THIS WILL MARK THE
BEGINNING OF A PERIOD OF MORE PRONOUNCED WARM ADVECTION THAT
WILL PROVIDE THE WARMEST HIGHS POTENTIALLY IN THE 50S FOR
THURSDAY AND FRIDAY.
ALONG WITH THE LATE WORKWEEK WARMTH WILL COME AN INCREASINGLY ACTIVE
PATTERN IN TERMS OF ADDITIONAL PRECIP CHANCES. THE FIRST FEATURE OF
INTEREST IS THE EVENTUAL INGESTION OF A CUT-OFF UPPER LOW FEATURE
FROM BAJA OF CALIFORNIA. THIS DISTURBANCE SHOULD BE ENTERING A
ANTICYCLONIC SHEARED ENVIRONMENT AS IT LIFTS ACROSS CENTRAL CONUS
THURSDAY AFTERNOON. HOW QUICKLY THIS FEATURE LOSES ITS AMPLITUDE
SHOULD HELP DETERMINE WHERE BEST FORCING/MOISTURE TRANSPORT END UP,
BUT IN ANY SCENARIO THIS STILL APPEARS TO BE HIGH RAIN COVERAGE
EVENT WITH RENEWED WARM/MOIST ADVECTIVE FORCING THURSDAY/THURSDAY
NIGHT VIA A 50-60 KNOT LOW LEVEL JET. A HIGHLY ANOMALOUS MOISTURE
AXIS WITH PWATS OVER OF 1.3+ INCHES AND IVT ANOMALIES OF 3-4
STANDARD DEVIATIONS THURSDAY AFTERNOON SHOULD SET THE STAGE FOR
WIDESPREAD RAIN AS THIS WAVE EVENTUALLY DAMPENS ACROSS THE WESTERN
GREAT LAKES THURSDAY NIGHT. PROGRESSION OF THESE FEATURES SHOULD
PREVENT ANY SIGNIFICANT FLOOD CONCERNS, BUT RAINFALL AMOUNTS IN THE
0.25-0.75 INCH RANGE APPEAR POSSIBLE. HIGHEST AMOUNTS IN THE
THURSDAY-FRIDAY AM PERIOD SHOULD BE ACROSS NORTHWEST IN/SW LOWER
MICHIGAN WHICH WILL BETTER ALIGNED WITH INITIAL STRONGEST MOISTURE
TRANSPORT WITH WARM FRONTAL FORCING THU PM/THU NIGHT.
THE SECOND PHASE OF THIS MORE ACTIVE PATTERN WILL OCCUR FRIDAY NIGHT
THROUGH THE WEEKEND AS A COMPLEX EVOLUTION UNFOLDS WITH AMPLIFYING
FOUR CORNERS UPPER TROUGH AND AN ADDITIONAL DIGGING UPPER WAVE
ACROSS THE DAKOTAS. GUIDANCE HAS HAD A DIFFICULT TIME RESOLVING
POTENTIAL PHASING ISSUES IN THIS PATTERN AND JUST HOW QUICKLY THIS
PHASING OCCURS IF IT DOES. THIS UNCERTAINLY CAN BE SEEN IN
GEFS/EPS ENSEMBLE MINIMUM MSLP MEMBER PLACEMENT WITH A VAST
LONGITUDINAL RANGE FROM THE NORTHERN GREAT LAKES INTO SOUTHWEST
QUEBEC BY SUNDAY. BEST MOISTURE WILL LIKELY BE SHUNTED
EAST/SOUTHEAST OF THE AREA BY THE INITIAL WAVE THURSDAY WITH
ONLY A BRIEF WINDOW OF RETURN MOISTURE TRANSPORT LATER FRIDAY,
BUT STRONGLY FORCED NATURE OF THIS SYSTEM ARGUES FOR MAINTAINING
BLENDED GUIDANCE IDEA OF LIKELY POPS LATE FRIDAY INTO SATURDAY
WITH EVENTUAL PREFERENCE TO SNOW SHOWERS. CONFIDENCE IS LOW ON
ENDING TIME OF PRECIP CHANCES LATER THIS WEEKEND/EARLY NEXT WEEK
DEPENDING ON PHASING SCENARIOS AND RESULTANT RESIDENCE TIME OF
ANY GREAT LAKES AGGREGATE TROUGHS/DEFORMATION FORCING LINGERING
LATE WEEKEND. THE TREND TO MORE SEASONABLE, COLDER TEMPS STILL
APPEARS ON TRACK FOR EARLY NEXT WEEK.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 623 AM EST TUE JAN 6 2026
A WARM FRONT IS WORKING ITS WAY NORTH THROUGH INDIANA RESULTING
IN A BLOSSOMING AREA OF DRIZZLE AND DECLINING CEILINGS. STEADY
RAIN IS FAVORED TO PASS NORTH OF THE TERMINALS WHERE THE BEST
COLOCATION OF FORCING RESIDES. THE ASSOCIATED SURFACE LOW TRACKS
ACROSS NORTHERN INDIANA TODAY KEEPING DRIZZLE, FOG, AND IFR TO
LIFR CEILINGS IN PLACE THROUGH THE DAY. SUBSIDENCE INVERSION
REMAINS IN PLACE TONIGHT.
VISIBILITY OFFERS SOME UNCERTAINTY, ESPECIALLY TONIGHT, WITH A
LARGE SPREAD IN MODEL GUIDANCE NOTED IN CONTRAST TO AGREEABLE
OF IFR-LIFR CEILINGS. SUCH CEILINGS WOULD TYPICALLY PAIR WELL
CLIMATOLOGICALLY WITH 1SM-2SM.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...MARSILI
AVIATION...BROWN
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