919
FXUS63 KIWX 220051
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
851 PM EDT SUN JUN 21 2026
KEY MESSAGES
- WIDESPREAD RAIN IS EXPECTED THIS EVENING AND OVERNIGHT. MOST
LOCATIONS WILL SEE AROUND AN INCH WITH POCKETS OF TWO INCHES
OR MORE POSSIBLE.
- HIGH WAVES AND DANGEROUS CURRENTS ARE EXPECTED ON LAKE
MICHIGAN BEACHES MONDAY AFTERNOON INTO MONDAY NIGHT.
- THE REST OF THE WEEK WILL FEATURE SLIGHTLY BELOW NORMAL
TEMPERATURES AND PERIODIC CHANCES FOR LIGHT RAIN.
UPDATE
ISSUED AT 850 PM EDT SUN JUN 21 2026
INITIAL DRY EASTERLY LOW LEVEL FLOW HAS MADE SUBSTANTIAL
RAINFALL ACCUMULATIONS DIFFICULT TO COME BY THROUGH EARLY THIS
EVENING. THE HIGHEST RAINFALL RATES THROUGH EARLY EVENING HAVE
BEEN CONFINED TO CENTRAL/SOUTHERN IN IN CLOSER PROXIMITY TO A
CONVECTIVELY ENHANCED SHORT WAVE AT NOSE OF RIDGE OF HIGHER
MLCAPES. A LARGER SCALE SYNOPTIC SHORT WAVE TROUGH ENTERING
WESTERN GREAT LAKES THIS EVENING SHOULD ALLOW FOR SOME SLIGHT
NORTHWARD MIGRATION OF SFC/LOW LEVEL WARM FRONTAL FEATURE
THROUGH THE OVERNIGHT HOURS, WITH A POSSIBILITY OF SOME WEAK
MLCAPE WORKING INTO NORTHEAST INDIANA SOUTH OF US ROUTE 24 FOR
EARLY OVERNIGHT. FORCING WITH THE UPSTREAM IL WAVE WILL KEEP
SCATTERED TO NUMEROUS SHOWERS IN PLACE FOR MUCH OF THE EVENING
WITH AN ISOLATED STORM POSSIBLE ESPECIALLY ALONG AND SOUTH OF US
ROUTE 24. BY THE EARLY OVERNIGHT, SOME INDICATIONS THAT A WEAK
MID LEVEL DRY SLOT COULD PUNCH ACROSS WEST CENTRAL/CENTRAL IN
WITH 900-800 MB FRONTAL ZONE STALLING OUT ACROSS FAR NORTHERN
IN/FAR NORTHWEST OH. THIS STALLED ELEVATED FRONT NORTH OF THE
PUNCH OF SLIGHTLY DRIER MID LEVEL AIR COULD ALLOW FOR SOME
MODEST LOW LEVEL MOISTURE POOLING WITH SOME SUSTAINED FGEN/LOW
LEVEL CONVERGENCE ACROSS THE NORTH. CURRENT INDICATIONS MIGHT
SUGGEST GREATEST POTENTIAL OF HEAVY RAIN COULD BE ALONG THIS
900-800 CONVERGENCE AXIS ACROSS THE NORTH, ALONG AND NORTH OF
US-6. THE SEVERE WEATHER POTENTIAL STILL APPEARS TO BE
CONFINED TO AREAS ACROSS THE SOUTH, BUT THE POTENTIAL OF SOME
MINOR FLOODING APPEARS TO BE THE MAIN FORECAST CONCERN FOR THE
REMAINDER OF TONIGHT. WHILE BEST SYNOPTIC SIGNALS FOR HEAVY
RAINFALL MAY BE ACROSS THE NORTH, HIGH PWAT AIRMASS AND LOW CAPE
ENVIRONMENT WITH INCOMING SHORT WAVE WILL BE CONDUCIVE FOR
BRIEF HEAVIER DOWNPOURS FORECAST AREA-WIDE INTO THE OVERNIGHT
HOURS. WIDSPREAD SIGNIFICANT FLOODING IS NOT ANTICIPATED AT THIS
TIME, BUT SOME MINOR FLOODING/URBAN AND SMALL STREAM FLOODING
STILL APPEARS POSSIBLE.
DISCUSSION
ISSUED AT 130 PM EDT SUN JUN 21 2026
A LOW PRESSURE SYSTEM CURRENTLY CENTERED OVER MISSOURI WILL
CONTINUE TO TRACK NORTHEASTWARD THIS AFTERNOON AND EVENING,
SPREADING RAIN ACROSS THE FORECAST AREA. THERE WAS PREVIOUSLY
SOME MARGINAL CONCERN FOR SEVERE STORMS SOUTH OF US-24, BUT
THIS HAS SINCE BEEN PULLED FARTHER SOUTH GIVEN THE EVOLUTION OF
THE MCS OVER SOUTHERN ILLINOIS. WHILE EMBEDDED THUNDER CAN STILL
BE EXPECTED THIS EVENING DUE TO WEAK INSTABILITY AND GOOD BULK
SHEAR EXCEEDING 50 KTS, THE MAIN STORY WILL BE MODERATE TO HEAVY
RAIN. PRECIPITABLE WATER WILL APPROACH 2 INCHES, ESPECIALLY TO
THE SOUTH. THEREFORE, 1 TO 2 INCHES OF RAIN IS POSSIBLE ACROSS
MUCH OF THE AREA. HOWEVER, UNCERTAINTY IN CONVECTIVE EVOLUTION
AND OVERALL MODEST INGREDIENTS CONTINUE TO PRECLUDE A FLOOD
WATCH HERE. MOST OF OUR AREA MISSED OUT ON HEAVY RAIN WED NIGHT
AND WE SHOULD BE ABLE TO HANDLE A WIDESPREAD 1" EVENT, EVEN WITH
POCKETS OF AROUND 2".
SCATTERED, LIGHT RAIN SHOWERS LIKELY PERSIST THROUGH MOST OF
THE DAY MONDAY AS A SECONDARY SHORTWAVE MOVES THROUGH THE
REGION, AND NORTHERLY FLOW WILL LIKELY KEEP HIGHS IN THE LOW
70S. WE WILL THEN SEE A GRADUAL WARMUP THROUGH THE REMAINDER OF
THE WEEK DUE TO ZONAL FLOW ALOFT. A FRONT WILL MOVE THROUGH
WEDNESDAY NIGHT/THURSDAY WITH MORE SHOWERS AND THUNDERSTORMS,
FOLLOWED BY ANOTHER WET WEATHER DISTURBANCE SATURDAY.
AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 800 PM EDT SUN JUN 21 2026
A COUPLE OF SHORT WAVES ARE PROGRESSING ACROSS THE SOUTHERN
GREAT LAKES AND OHIO VALLEY THIS EVENING. A LARGER SCALE UPPER
LEVEL SHORT WAVE CONTINUES TO APPROACH NW INDIANA THIS EVENING
WHILE A STRONG BUT SMALLER SCALE VORT MAX ASSOCIATED WITH
COMPLEX OF THUNDERSTORMS MOVES ACROSS CENTRAL/SOUTHERN INDIANA.
THE LOW AMPLITUDE NATURE OF THE FLOW IS LIMITING THE PROGRESS
OF THE ACTUAL SFC BOUNDARY TO SOUTH CENTRAL INDIANA. THIS SFC
FRONT MAY MAKE SOME NORTHEAST PROGRESS LATER THIS EVENING INTO
EAST CENTRAL IN, BUT SHOULD REMAIN WELL SOUTH OF THE TERMINALS.
THIS SHOULD ALSO KEEP MORE PRONOUNCED MLCAPE SOUTH OF THE
TERMINALS WITH JUST A LOW PROBABILITY OF AN ISOLATED STORMS
TONIGHT GIVEN SOME WEAK ELEVATED INSTABILITY. THE HEAVIEST
RAINFALL LATE EVENING OVERNIGHT MAY END UP SETTING UP ALONG AND
NORTH OF THE I-80 CORRIDOR WHERE 850 MB FRONT IS EXPECTED TO
STALL OUT. RAIN SHOWERS WILL BE SLOW TO END LATE TONIGHT INTO
EARLY TUESDAY DUE TO PRESENCE OF STRONG LOW LEVEL FRONT AND
ANOTHER UPSTREAM VORT MAX DIGGING IN FROM IOWA. CIGS SHOULD
DETERIORATE TO LOWER END MVFR/IFR LATE THIS EVENING INTO THE
OVERNIGHT HOURS, WITH IMPROVEMENT FROM NW TO SE MONDAY MORNING
INTO EARLY AFTERNOON AS THE FRONT SLIPS TO THE SOUTHEAST AND
DRIER AIR BUILDS SOUTHWARD. OTHERWISE, EAST WINDS WILL INCREASE
IN GUSTINESS TO AROUND 20 KNOTS THIS EVENING AS EASTERLY
GRADIENTS TIGHTENS IN RESPONSE TO CONVECTIVELY ENHANCED SFC LOW
PRESSURE TO THE SOUTH.
IWX WATCHES/WARNINGS/ADVISORIES
IN...BEACH HAZARDS STATEMENT FROM 7 AM CDT MONDAY THROUGH LATE
MONDAY NIGHT FOR INZ103.
OH...NONE.
MI...BEACH HAZARDS STATEMENT FROM MONDAY AFTERNOON THROUGH LATE
MONDAY NIGHT FOR MIZ177-277.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM MONDAY TO 5 AM EDT TUESDAY FOR
LMZ043.
SMALL CRAFT ADVISORY FROM 8 AM MONDAY TO 5 AM EDT TUESDAY FOR
LMZ046.
UPDATE...MARSILI
DISCUSSION...COBB
AVIATION...MARSILI
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