222
FXUS63 KIWX 101043
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
643 AM EDT TUE MAR 10 2026
KEY MESSAGES
- AN ENHANCED RISK OF SEVERE STORMS (ROUGHLY ALONG/WEST OF
IN-15), MAINLY LATE THIS AFTERNOON INTO THE OVERNIGHT HOURS
TONIGHT. A SLIGHT RISK OF SEVERE STORMS FOR REMAINDER OF THE
AREA. ALL SEVERE HAZARDS ARE POSSIBLE THIS EVENING INTO AT
LEAST THE EARLY OVERNIGHT HOURS , EVENTUALLY TRANSITIONING TO
A HEAVY RAIN AND FLOODING THREAT EARLY WEDNESDAY MORNING.
- LOCALLY HEAVY RAINFALL IS EXPECTED TONIGHT INTO EARLY
WEDNESDAY WITH A POTENTIAL OF SOME LOCALIZED FLOODING. HEAVY
RAINFALL TONIGHT MAY LEAD TO MINOR RIVER FLOODING LATER THIS
WEEK. SOME ISOLATED SEVERE THREAT IS ALSO POSSIBLE ON
WEDNESDAY EAST OF I-69 AND SOUTH OF US ROUTE 24.
- A FRONTAL BOUNDARY ACROSS THE REGION WILL INTERACT WITH
SEVERAL OTHER SYSTEMS FOR PERIODIC CHANCES OF RAIN AND SNOW
LATE WEEK INTO EARLY NEXT WEEK. SOME LIGHT SNOW ACCUMULATIONS
POSSIBLE LATE SUNDAY/MONDAY.
DISCUSSION
ISSUED AT 403 AM EDT TUE MAR 10 2026
OVERALL, NO MAJOR CHANGES AT THIS TIME REGARDING MESSAGING FOR THE
POTENTIAL SEVERE WEATHER EVENT LATE THIS AFTERNOON INTO TONIGHT.
SEVERE WEATHER RISK MAY PERSIST INTO PORTIONS OF THE OVERNIGHT HOURS
BEFORE TRANSITIONING TO MAINLY A HEAVY RAIN AND ISOLATED WIND THREAT
LATE TONIGHT INTO EARLY WEDNESDAY. THE GREATEST POTENTIAL OF HIGHER
END SEVERE THREATS INCLUDING SUPERCELLS WITH HAIL TO 2 INCHES IN
DIAMETER AND TORNADOES IS LATE THIS AFTERNOON AND ESPECIALLY THIS
EVENING ACROSS THE ENHANCED RISK AREA.
AN INITIAL ADVECTION PUSH OF HIGHER LOW LEVEL THETA-E AIR IS
OVERSPREADING THE SOUTHERN GREAT LAKES THIS MORNING. TO THIS POINT,
THIS HAS JUST BEEN ACCOMPANIED BY INCREASING LOW CLOUD COVER,
WITH LIKELY JUST ENOUGH CIN FOR ELEVATED PARCEL TO LIMIT SHOWER
DEVELOPMENT. A WEAK SHEARED VORTICITY MAX AT 500 MB IS EXPECTED
TO LIFT NORTHEAST FROM THE SOUTHERN STREAM CUT-OFF UPPER TROUGH
AND COULD BE ENOUGH IMPETUS FOR A FEW SHOWERS AND PERHAPS EVEN
AN ISOLATED LIGHTNING STRIKE HEADING THROUGH MID MORNING. WILL
MAINTAIN JUST SLIGHT CHANCE POPS TO COVER THIS PROSPECT.
FOR LATER THIS MORNING, A SOUTHEAST CANADIAN SHORT WAVE WILL
CONTINUE TO ALLOW FOR SLOWLY SOUTHWARD SAGGING SFC TROUGH ACROSS THE
SOUTHERN GREAT LAKES. THIS BOUNDARY IS EXPECTED TO STALL TOWARD
MIDDAY WITH BEST SOUTHWARD PUSH ACROSS NW INDIANA NEAR SHORELINE
AIDED BY A COLD LAKE MICHIGAN. LOW LEVEL SOUTHWESTERLIES WILL
INCREASE TO THE SOUTH/SOUTHWEST OF THIS BOUNDARY THIS AFTERNOON,
WITH A RENEWED STRONGER LOW LEVEL THETA-E PUSH TOWARD 21Z. LOW
CLOUDS SOUTH OF THE BOUNDARY SHOULD TEND TO SCATTER SOME THIS
AFTERNOON WITH SOME SUN AND BETTER AFTERNOON MIXING ALLOWS HIGH
TO REACH WELL INTO THE 70S FOR AT LEAST SOUTHERN PORTIONS OF THE
AREA. THE GREATEST ITEM OF UNCERTAINTY IN THIS FORECAST DEALS
WITH CONVECTIVE INITIATION TIMING LATER THIS AFTERNOON AND THIS
EVENING. THE COMBINATION OF THE STALLED LOW LEVEL BOUNDARY AND A
MID LEVEL SPEED MAX NOSING INTO NORTHERN ILLINOIS SHOULD PROVIDE
INGREDIENTS FOR INITIATION IN THE 21Z-00Z TIMEFRAME BUT THE EXACT
LOCATION OF THIS INITIAL CONVECTION IS STILL OF LOWER CONFIDENCE.
STEEP MID LEVEL LAPSE RATES AND WELL MIXED LAYER ALOFT ARE MAIN
CONTRIBUTING FACTORS TO THIS UNCERTAINTY AS THEY POSE A BOOST TO
INSTABILITY MAGNITUDES THIS AFTERNOON, BUT ALSO A POTENTIAL OF
SOME INITIAL CAPPING.
THERE ALSO REMAINS SOME CONFLICTING SIGNALS IN THE EXTENT OF
LOW LEVEL WARMING SOUTH OF THE BOUNDARY AND DEPTH OF MIXED LAYER
WHICH WILL HAVE A BIG IMPACT ON MAGNITUDE OF HELICITY PROFILES
IN TERMS OF TORNADIC POTENTIAL. LOCATIONS NEAR THE SFC BOUNDARY
AND JUST TO THE COOL SIDE OF THE SURFACE BOUNDARY STILL APPEAR
THE MOST LIKELY LOCATIONS FOR CONVECTIVE INITIATION AFTER 21Z
ACROSS ILLINOIS, BUT THERE IS SOME POSSIBILITY IT MAY TAKE A
LITTLE LONGER TO OVERCOME WEAK CIN INTRODUCED BY THE MIXED LAYER
ALOFT WHEN CONSIDERING HOW SHALLOW THE FRONTAL CONVERGENCE WILL
BE. IF CONVECTION IS ABLE TO DEVELOP IN VICINITY OF THIS
BOUNDARY, ALL SEVERE HAZARDS WOULD BE IN PLAY FOR LATE
AFTERNOON/EARLY EVENING ACROSS WESTERN PORTIONS OF IN CWA DUE TO
1500-2000 J/KG OF MLCAPE, AND ENHANCED LOW LEVEL SRH NEAR THE
LAKE MICHIGAN REINFORCED LOW LEVEL FRONT FOR A TORNADIC
SUPERCELL POTENTIAL. ADDITIONAL INITIAL STORMS COULD ALSO
DEVELOP WELL NORTH OF THE BOUNDARY ACROSS FAR NORTHERN IL INTO
LOWER MICHIGAN WHERE HAIL WOULD LIKELY BE THE GREATEST THREAT
BUT A TORNADIC POTENTIAL COULD EVOLVE WITH EXPECTATION BOUNDARY
MAY SHIFT NORTH A BIT LATER THIS EVENING ALLOWING SURFACE BASED
CAPE AXIS TO MIGRATE NORTHWARD. THE SEVERE THREAT WITH ALL
HAZARDS POSSIBLE WILL LIKELY CONTINUE INTO AT LEAST THE EARLY
OVERNIGHT HOURS AS A STRENGTHENING LOW LEVEL JET PROVIDES
FAVORABLE KINEMATIC PROFILES AND THE UNSEASONABLY MOIST AIRMASS
ALLOWS CONVECTION TO BE NEAR-SFC BASED IF NOT SFC BASED INTO
EARLY OVERNIGHT. CONVECTION WILL LIKELY TAKE ON MORE LINEAR MODE
LATE TONIGHT AS BOUNDARY PARALLEL FLOW ALLOWS FOR CONGEALING
STORMS WITH INCREASING HEAVY RAIN THREAT INTO EARLY WEDNESDAY.
BY DAYBREAK WEDNESDAY, STRONG MID/UPPER SUPPORT SHIFTS IN FROM THE
WEST ALLOWING SFC CYCLONE TO LIFT ACROSS SOUTHEAST ONTARIO DRAGGING
A COLD FRONT THROUGH THE REGION. SOME ISOLATED WIND THREAT IS
POSSIBLE FAR SOUTHEAST WEDNESDAY, ALTHOUGH PRIMARY INSTABILITY AXIS
STILL LOOKS TO BE POSITIONED ACROSS SOUTH CENTRAL OHIO. SOME SNOW
MAY MIX IN BRIEFLY ACROSS THE NW LATE WEDNESDAY BEFORE PRECIP
DIMINISHES.
NO MAJOR CHANGES TO THE NATURE OF THE LONG TERM FORECAST THIS CYCLE
AS A VERY ACTIVE EASTERN PACIFIC PATTERN INTERACTS WITH WAVERING
FRONTAL BOUNDARY FOR ADDITIONAL RAIN CHANCES. A STRONGER SYNOPTIC
SYSTEM AND STRONGER BAROCLINIC ZONE COULD PROVIDE A SHOT OF
SNOW LATE WEEKEND INTO EARLY NEXT WEEK WHICH WILL BE FOLLOWED BY
A RETURN OF BELOW NORMAL TEMPERATURES.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 640 AM EDT TUE MAR 10 2026
BROAD LOW LEVEL THETA-E ADVECTION CONTINUES THIS MORNING, BUT TO
THIS POINT SHOWERS HAVE HAD A DIFFICULT TIME DEVELOPING. A WEAK
SHEARED VORT MAX WILL LIFT INTO NORTHERN INDIANA THIS MORNING
WHICH MAY BE ENOUGH TO GENERATE ISOLATED SHOWERS AND POSSIBLY A
STRAY THUNDERSTORM. EXPECTED COVERAGE AND CONFIDENCE OF
OCCURRENCE IS TOO LOW TO INCLUDE WITH THE 12Z TAFS. SCATTERED
SHOWERS AND STORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AS A
LOW LEVEL BOUNDARY INTERACTS WITH INCREASING SOUTHERLY FLOW.
CONFIDENCE IN SHOWERS AND STORMS INCREASES TOWARD 00Z AND
THROUGH TONIGHT AS A LOW LEVEL JET STRENGTHENS AND INTERACTS
WITH A HIGHLY ANOMALOUS MOIST AIRMASS. THUNDER MENTIONS HAVE
BEEN MAINTAINED TONIGHT WITH A POTENTIAL SOME OF THESE STORMS
COULD PRODUCE SOME HAIL AND STRONG WIND GUSTS IN EXCESS OF 40
KNOTS. OTHERWISE TODAY, THE INITIAL WARM/MOIST ADVECTION HAS
LED TO EXTENSIVE MVFR CIGS. WHILE THE BACK EDGE OF THESE CLOUDS
IS JUST WEST OF KSBN, WOULD EXPECT THAT LOW CLOUDS WILL FILL
BACK IN AS A LOW LEVEL FRONT DROPS ACROSS THE SOUTHERN GREAT
LAKES WITH A POTENTIAL OF A PERIOD OF IFR CIGS AT KSBN THIS
MORNING.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 AM WEDNESDAY TO 11 AM EDT
THURSDAY FOR LMZ043-046.
DISCUSSION...MARSILI
AVIATION...MARSILI
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page