897
FXUS63 KIWX 120522
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
122 AM EDT WED AUG 12 2026
KEY MESSAGES
- RAIN CHANCES MAY LINGER THROUGH THE WEEK, ESPECIALLY SOUTH OF US-
30.
DISCUSSION
ISSUED AT 1122 AM EDT TUE AUG 11 2026
WILL FOCUS ON THE NEAR TERM FOR THIS DISCUSSION WITH A RATHER
BUSY MORNING WITH THE CONTINUATION OF CONVECTIVE ACTIVITY ALONG
A BOUNDARY DRAPED FROM THE WEST OUT OVER NORTHERN IL AND THEN
IN A SOUTHEASTERLY ORIENTATION INTO OUR SOUTHERN PORTIONS OF THE
CWA. THE ACTIVITY HAS CURRENTLY BEEN DEVELOPING ALONG THIS
BOUNDARY AND TRAINING OVER THE SAME AREAS WHICH HAS INCREASED
THE THREAT OF FLASH FLOODING AND AREAL FLOODING IN THOSE AREAS.
THIS WILL ONLY BE EXASPERATED FURTHER WITH THE EXPECTATION OF
THE STORMS CONTINUING ACROSS THAT AREA INTO THE THIS EVENING
WITH PERIODS OF HEAVY RAINFALL TO CONTINUE. A FLASH FLOOD WATCH
IS IN EFFECT UNTIL 8 PM EDT FOR ALL OF THE INDIANA AND OHIO
COUNTIES IN OUR CWA. ALSO, WITH A LARGE CONVECTIVE BOW STRUCTURE
SITTING NORTHERN IL AND PUSHING EASTWARD INTO THE AREA THIS
WILL HELP PUSH CONVECTION FURTHER NORTH AND SOUTHWARD FROM THE
BOUNDARY EXPANDING THE AREAL COVERAGE TO THE REST OF THE CWA
INTO THIS LATE AFTERNOON AND EARLY EVENING.
SHOWERS/THUNDERSTORMS MAY CONTINUE BEYOND THAT ESPECIALLY THE
SOUTHERLY HALF OF THE CWA INTO THE OVERNIGHT HOURS.
WITH THE VERY MOIST AIRMASS IN PLACE AND PLENTY OF INSTABILITY
RANGING FROM AROUND 1500 J/KG TO THE EASTERN PORTIONS OF THE
AREA TO AROUND 4500 J/KG FOR OUR WEST AND SOUTHWEST PORTIONS OF
THE AREA. BULK SHEAR VALUES OF 40 TO 50 KTS WITH EVEN A FEW
POCKETS AROUND 60 KTS PUSHING INTO THE AREA FROM THE WEST WITH
THE MCS DISTURBANCE CURRENTLY OVER NORTHERN IL. THE INCREASED
SHEAR LOOKS TO KEEP THE THINGS MORE ORGANIZED AND WILL BE
INTERESTING TO SEE HOW THIS EVOLVES AS IT PUSHES THROUGH THE
AREA. ALL THREATS ARE ON THE TABLE BUT DAMAGING WINDS AND THE
HEAVY RAINFALL SEEMS TO BE THE MAIN EXPECTED THREATS AT THIS
TIME, BUT WITH MARGINAL SR HELICITY VALUES AROUND 100 M2/S2
TORNADIC SPIN-UPS WOULD BE POSSIBLE ESPECIALLY ALONG THE MAIN
BOWING STRUCTURE AND POTENTIAL BOOKEND VORTICIES. THE HELICITY
VALUES DO LOOK TO PEAK LATER THIS AFTERNOON IN THE REAR OF THIS
BOWING STRUCTURE SO WILL NEED TO WATCH OUT FOR STORMS THAT MAY
DEVELOP IN IT'S WAKE LATER TODAY FOR THE POTENTIAL FOR SPIN-UPS.
SPC DOES CURRENTLY HAVE A MAJORITY OF OUR CWA, ESPECIALLY THE
SOUTHWESTERN HALF UNDER AN ENHANCED RISK FOR SEVERE STORMS
TODAY AND A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR THE
ENTIRE CWA UNTIL 5 PM EDT THIS EVENING.
THE MAIN BOUNDARY PUSHES SOUTHWARD TONIGHT AND WILL SEE THE
SHOWER/THUNDERSTORM ACTIVITY DO THE SAME WITH THE BETTER CHANCES
FOR MAINLY OUR SOUTHERN PORTIONS OF THE CWA (MAINLY SOUTH OF
US-30 AND MOST LIKELY SOUTH OF US-24). SPC DOES HAVE A MARGINAL
RISK FOR SEVERE STORMS FOR OUR FAR SOUTHERN PORTIONS OF THE CWA.
WITH THIS STAGNANT RING OF FIRE/ZONAL FLOW PATTERN TO CONTINUE
THROUGH THE END OF THE WEEK AND INTO THE WEEKEND PERIODS OF
SHOWERS/STORMS WILL BE POSSIBLE EACH DAY ACROSS THE AREA WITH
AFTERNOONS AND EVENING PERIODS WITH THE GREATER CHANCES.
SEASONABLE TEMPERATURES WILL ALSO REMAIN THE THEME. HOWEVER, WILL
BE WATCHING FOR RIDGING FROM THE SOUTH TO PUSH NORTHWARD WHICH
WILL MAKE FOR WARMER TEMPERATURES AND MORE HUMID CONDITIONS BUT
STILL A DECENT AMOUNT OF UNCERTAINTY ON THE LONGER RANGE
FORECAST.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 122 AM EDT WED AUG 12 2026
CHALLENGING AVIATION FORECAST THIS MORNING WITH FOG, STRATUS,
AND THUNDERSTORMS ALL A POSSIBILITY. FRONT IS DRAPED JUST
SOUTHWEST OF THE TERMINALS AND HI-RES CAM'S STILL STRUGGLING TO
RESOLVE TIMING AND LOCATION OF CONVECTION. TWO ROUNDS ARE
POSSIBLE EARLY THIS MORNING AND AROUND MIDDAY BUT CONFIDENCE IS
LOW FOR BOTH. SOME PATCHY FOG HAS ALSO DEVELOPED BUT INCREASING
HIGH CLOUDS SHOULD LIMIT THE DURATION AND DENSITY. OF SOMEWHAT
HIGHER CONFIDENCE IS THE POTENTIAL FOR STRATUS DEVELOPMENT EARLY
THIS MORNING GIVEN GREATER CONSISTENCY IN NUMERICAL GUIDANCE ON
THAT ASPECT OF THE FORECAST. ANTICIPATE AT LEAST PERIODS OF IFR
CEILINGS THROUGH THE EARLY MORNING. RETURN TO VFR/MORE TRANQUIL
WEATHER NOT EXPECTED UNTIL LATE AFTERNOON.
IWX WATCHES/WARNINGS/ADVISORIES
IN...FLOOD WATCH THROUGH THIS EVENING FOR INZ012>015-017-018-020-
022>027-032>034-116-203-216.
OH...FLOOD WATCH THROUGH THIS EVENING FOR OHZ024-025.
MI...NONE.
MARINE...NONE.
DISCUSSION...ANDERSEN
AVIATION...AGD
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