732
FXUS63 KIWX 151707
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
107 PM EDT SAT AUG 15 2026
KEY MESSAGES
- AN ISOLATED STRONG TO SEVERE STORM OR TWO POSSIBLE BETWEEN 4-8
PM EDT TODAY, MAINLY EAST OF I-69 AND THE US 30 CORRIDOR.
MAIN THREATS WILL BE DAMAGING WINDS AND AN ISOLATED TORNADO.
- ADDITIONAL ROUND OF RAIN AND SUB-SEVERE STORMS LIKELY BETWEEN 4 AM
AND NOON EDT.
- FLOOD WATCH CONTINUES ALONG AND SOUTH OF US 30 WHERE HEAVY RAIN
WILL CONTINUE TO EXACERBATE ONGOING FLOODING THROUGH SUNDAY.
- DRY CONDITIONS RETURN MONDAY AND TUESDAY.
DISCUSSION
ISSUED AT 1230 PM EDT SAT AUG 15 2026
STRATIFORM RAIN CONTINUES TO DIMINISH AS OF MIDDAY, ALTHOUGH THERE
ARE STILL SOME AREAS OF LIGHT RAIN ONGOING SOUTH OF US 24. VISIBLE
SATELLITE SHOWS A FEW POCKETS OF CLEARING AS AN MCV APPROACHES THE
IL/IN BORDER, BUT MORE WIDESPREAD BREAKS IN THE CLOUDS WILL BE
NEEDED TO RECHARGE THE ATMOSPHERE FOR POTENTIAL STORMS THIS
AFTERNOON AND EVENING. IT IS WORTH NOTING THAT ISOLATED STRONG TO
SEVERE STORMS ARE STILL POSSIBLE DESPITE THE DOWNGRADE FROM SPC TO A
MARGINAL RISK (LEVEL 1 OF 5) FOR SEVERE WEATHER TODAY. THE
AFOREMENTIONED MCV IS EXPECTED TO MOVE ACROSS NORTHERN INDIANA THIS
AFTERNOON AND EVENING. STORM DEVELOPMENT IS POSSIBLE BETWEEN 4-8 PM
EDT TODAY. COVERAGE WILL LIKELY BE SPATIALLY LIMITED AS THE BETTER
ENVIRONMENT IS OFF TO OUR SOUTHWEST, HOWEVER, I THINK THE BEST
CHANCES FOR ISOLATED SEVERE WEATHER TODAY WILL BE MAINLY EAST OF I-
69 AND ALONG/SOUTH OF US 30. THIS WOULD INCLUDE GRANT, BLACKFORD,
JAY, WABASH, ADAMS, AND ALLEN COUNTIES IN INDIANA AND DEFIANCE,
HENRY, PUTNAM, PAULDING, PUTNAM, AND VAN WERT IN OHIO. MODELS VARY
WIDELY ON A SOLUTION, WITH SOME SHOWING NO STORMS AND SOME SHOWING
DISCRETE CELLS CAPABLE OF PRODUCING SEVERE WEATHER. 30-40 KTS OF 0-
6KM SHEAR, 100-200 M2/S2 OF 0-1 SRH, AND A NARROW CORRIDOR OF
MODERATE INSTABILITY MAY DEVELOP ALONG THE I-69 CORRIDOR
DEPENDING ON HOW MUCH CLEARING WE CAN GET THIS AFTERNOON. THIS
WOULD BE A FAVORABLE ENVIRONMENT FOR DAMAGING WINDS AND AN
ISOLATED, BRIEF TORNADO. WITH A LOW END SEVERE THREAT, THIS IS A
HIGHLY CONDITIONAL SETUP DEPENDING ON CLEARING AND HOW MUCH THE
ATMOSPHERE HAS BEEN DEPLETED BY THIS MORNING'S RAIN. DESPITE
FAVORABLE SHEAR AND INSTABILITY, POOR LAPSE LOW AND MID LEVEL
RATES CAN BE SEEN IN FORECAST SOUNDINGS FROM MOST OF THE CAMS,
WHICH WILL LIKELY BE A LIMITING FACTOR.
WPC DOES HAVE A MODERATE RISK (LEVEL 3 OF 4) FOR EXCESSIVE RAINFALL
ALONG AND SOUTH OF US 30 TODAY, WHERE A FLOOD WATCH IS IN EFFECT.
STRONG MOISTURE TRANSPORT IS EXPECTED AND PRECIPITABLE WATER VALUES
WILL ONCE AGAIN BE AT OR ABOVE 2 INCHES TODAY. WITH SUCH HIGH
MOISTURE CONTENT IN THE AIRMASS OVERHEAD (99TH PERCENTILE PWATS AND
DEWPOINTS WELL INTO THE 70S), ANY STORM COULD BE A VERY EFFICIENT
RAINFALL PRODUCER WITH RAIN RATES BETWEEN 1-2" PER HOUR. GIVEN THAT
THE GROUND IS SO SATURATED SOUTH OF US 30, WHERE 6-12"+ OF RAIN HAS
FALLEN SINCE THIS PAST TUESDAY, RENEWED FLASH FLOODING IN AREAS THAT
HAVE ALREADY BEEN HARD HIT IS BECOMING AN INCREASING CONCERN. ON
THE VERY VERY LOW CHANCE THAT AN ISOLATED TORNADO OCCURS IN
EAST-CENTRAL INDIANA SOMEWHERE IN WELLS, ADAMS, GRANT,
BLACKFORD, AND JAY COUNTIES WHERE AREAL AND RIVER FLOODING IS
ONGOING, THE BEST RECOMMENDATION IS TO SAFELY SHELTER IN THE
LOWEST LEVEL AWAY FROM WINDOWS AND DOORS BUT TO STAY AWAY FROM
FLOODING.
ONE LAST ROUND OF SCATTERED RAIN AND STORMS IS LIKELY SUNDAY
MORNING, BECOMING MORE ISOLATED INTO THE AFTERNOON HOURS. WE WILL
HAVE TO MONITOR CONVECTION IN EASTERN IOWA AND NORTHERN ILLINOIS
OVERNIGHT THAT WILL MOVE EASTWARD. UNFORTUNATELY, THE AXIS OF
HEAVIEST RAIN LOOKS TO BE SOUTH OF THE US 30 CORRIDOR BEFORE
DAYBREAK SUNDAY AS THE LLJ RAMPS UP WITH THE STATIONARY FRONT IN THE
VICINITY. HIGH PWATS AND DEWPOINTS WILL CONTRIBUTE TO EFFICIENT,
HEAVY RAINFALL LATE OVERNIGHT INTO SUNDAY MORNING. THE PRIMARY
TIMEFRAME FOR RAIN AND STORMS LOOKS TO BE BETWEEN 4 AM TO NOON
EDT. AN ISOLATED STRONG STORM IS POSSIBLE SOUTH OF US 24, BUT
ONCE AGAIN, FLOODING IS EXPECTED TO POSE A HIGHER THREAT
SPATIALLY THAN SEVERE WEATHER. DUE TO THIS POTENTIAL, THE
CURRENT FLOOD WATCH HAS BEEN EXTENDED TO LAST UNTIL 8 AM EDT
SUNDAY.
A WELCOME BREAK FROM DAILY RAIN AND STORM CHANCES IS AHEAD! WE
FINALLY SEE A REPRIEVE IN THE 'RING OF FIRE' PATTERN MONDAY AND
TUESDAY AS HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES. THIS WILL
ALLOW FOR THE AREA TO DRY OUT, FLOODWATER TO RECEDE, AND FOR
RIVER LEVELS TO FALL. TEMPERATURES WILL BE SEASONABLE WITH HIGHS
IN THE UPPER 70S TO NEAR 80 DEGREES WITH LOTS OF SUN.
ANOTHER CHANCE FOR RAIN AND STORMS COMES WEDNESDAY WITH A COLD
FRONT, ALTHOUGH IT MAY BE SHORT LIVED AS HIGH PRESSURE LOOKS TO
RETURN OVER THE GREAT LAKES ONCE AGAIN. AFTER A VERY ACTIVE FIRST
HALF OF AUGUST AND A TOP 10 WETTEST AUGUST ON RECORD FOR SOME
LOCATIONS ALREADY, WE WOULD HAPPILY WELCOME A STRETCH OF DRY WEATHER
BY THE END OF THE WEEK INTO NEXT WEEKEND.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 103 PM EDT SAT AUG 15 2026
AN MCV IS SPINNING ACROSS NORTHERN INDIANA THIS AFTERNOON. AT
THE MOMENT, KSBN IS SOCKED IN WITH LOW STRATUS AND BR BUT THE
CENTER OF THIS MCV FAVORS A MODEST IMPROVEMENT TO MVFR
CEILINGS, WHILE ALSO SERVING AS THE FOCUS FOR ADDITIONAL SHOWERS
(AT BOTH SITES) WITHIN THE CRITICAL TAF PERIOD. HIGH CONFIDENCE
IN SOUPY CONDITIONS ONCE AGAIN EARLY SUNDAY MORNING DUE TO
ABUNDANT LOW- LEVEL MOISTURE AND STAGNANT SURFACE FLOW.
ANOTHER MID-LEVEL DISTURBANCE BRINGS SHOWERS AND THUNDERSTORMS
TO KSBN NEAR DAYBREAK, PERHAPS SURVIVING ALL THE WAY TO KFWA
PRIOR TO 18Z SUNDAY (MEDIUM CONFIDENCE)
IWX WATCHES/WARNINGS/ADVISORIES
IN...FLOOD WATCH THROUGH SUNDAY MORNING FOR INZ012-013-015-020-
022>027-032>034.
OH...FLOOD WATCH THROUGH SUNDAY MORNING FOR OHZ024-025.
MI...NONE.
MARINE...NONE.
DISCUSSION...JOHNSON
AVIATION...BROWN
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