785
FXUS63 KIWX 011926
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
326 PM EDT SAT AUG 1 2026
KEY MESSAGES
- SHOWERS AND SOME EMBEDDED THUNDERSTORMS WILL DEVELOP THIS
AFTERNOON AND CONTINUE TONIGHT. THERE IS A MARGINAL RISK OF SEVERE
STORMS THIS AFTERNOON INTO THIS EVENING SOUTH OF US ROUTE 24 FOR AN
ISOLATED WIND THREAT. A FLOOD WATCH HAS BEEN ISSUED FOR NORTHERN
INDIANA FROM EARLY THIS EVENING THROUGH SUNDAY AFTERNOON. LOCALIZED
RAINFALL AMOUNTS OF UP TO 4 INCHES ARE POSSIBLE WHERE RAIN SHOWER
BANDS TEND TO ANCHOR IN THE SAME LOCATIONS FOR A TIME TONIGHT INTO
SUNDAY MORNING. THE GREATEST THREAT OF FLOODING IS GENERALLY ALONG
AND SOUTH OF US ROUTE 24.
- DANGEROUS SWIMMING CONDITIONS ARE EXPECTED AT LAKE MICHIGAN
BEACHES ALONG THE LA PORTE COUNTY, IN AND BERRIEN COUNTY, MI
SHORELINE. LIFE- THREATENING WAVES AND CURRENTS ARE EXPECTED,
ESPECIALLY SUNDAY. A BEACH HAZARDS STATEMENT IS IN EFFECT. FOR
DETAILS, VISIT WWW.WEATHER.GOV/GREATLAKES/BEACHHAZARDS
- CONDITIONS DRY OUT FROM NORTHWEST TO SOUTHEAST LATER SUNDAY INTO
SUNDAY NIGHT.
DISCUSSION
ISSUED AT 321 PM EDT SAT AUG 1 2026
AFTER AN INITIAL BAND OF RAIN THAT SWEPT FROM WEST TO EAST ACROSS
THE AREA THIS MORNING, MOST OF THE LOCAL AREA HAS REMAINED DRY
THROUGH MID AFTERNOON DUE TO THE INFLUENCE OF A MID LEVEL DRY SLOT.
VORTICITY ADVECTION ASSOCIATED WITH MID/UPPER LEVEL LOW ACROSS
CENTRAL IL IS BEGINNING TO PUSH EASTWARD. AN INSTABILITY AXIS OF
1000-1500 J/KG SBCAPE IS CONTINUING TO NUDGE NORTHWARD IN MODEST
SOUTHERLY FLOW REGIME DOWNSTREAM IF THIS IL DISTURBANCE AND SHOULD
ALLOW FOR CONTINUED SHOWER AND STORM DEVELOPMENT ACROSS NORTHERN
INDIANA OVER THE NEXT SEVERAL HOURS. A POCKET OF STRONGER EFFECTIVE
SHEAR ON THE ORDER OF 30-35 KNOTS MAY END UP JUST SKIRTING FAR
SOUTH/SOUTHEAST PORTIONS OF THE FORECAST AREA ACROSS FAR NE IN/NW OH
EARLY THIS EVENING WHICH IS ALSO COINCIDENT WITH POCKET OF 100-150 0-
1KM SRH. SOME ISOLATED WIND THREAT IS POSSIBLE IN A BRIEF WINDOW
LATE THIS AFTERNOON/EARLY EVENING FAR SOUTH/SOUTHEAST, BUT CURRENTLY
EXPECTING GREATER POTENTIAL OF ISOLATED-SCATTERED SEVERE STORMS TO
REMAIN ACROSS CENTRAL IN.
THE POTENTIAL OF HEAVY RAINFALL WILL LIKELY BE THE PRIMARY IMPACT
LOCALLY. AN IMPRESSIVE LOW LEVEL THETA-E RIDGE THAT SHIFTED INTO THE
AREA THIS MORNING IS ACQUIRING MORE OF A WEST-NORTHWEST TO
EAST-SOUTHEAST ORIENTATION IN RESPONSE TO INDUCED CYCLONIC FLOW
FROM UPSTREAM IL MID/UPPER LEVEL LOW. THIS SHOULD CREATE
FAVORABLE DEEP MOISTURE PROFILES AND EFFICIENT WARM RAIN
PROCESSES TONIGHT INTO EARLY SUNDAY. SHOWERS AND EMBEDDED
STORMS SHOULD FILL IN ACROSS NORTHERN IN THROUGH EARLY EVENING
ESPECIALLY ALONG AND SOUTH OF US 24, WITH AN EVENTUAL PIVOT IN
ORIENTATION OF MOST FAVORED RAIN SHOWER AXIS TO SW-NE ORIENTED
FROM WEST CENTRAL IN TO AS POSSIBLY AS FAR EAST AS NW OHIO LATE
EVENING/EARLY OVERNIGHT AS DEFORMATION FORCING BEGINS TO SHARPEN
UP. THIS SETUP SHOULD PROVIDE FAVORABLE LOW LEVEL MOISTURE
CONVERGENCE FOR A RELATIVELY EXTENDED DURATION TONIGHT INTO
EARLY SUNDAY MORNING.
EARLIER TODAY, SOME HIGHLY EFFICIENT RAINFALL ACCUMULATION WAS NOTED
ACROSS NW INDIANA WITH THE LEADING BAND OF SHOWERS, WITH SOME
LOCATIONS PICKING UP A QUICK 1 TO 2 INCHES. EARLIER TODAY, DID GO
AHEAD AND ISSUE A FLOOD WATCH FOR POTENTIAL OF FLASH FLOODING/AREAL
FLOODING FOR ALL OF IN COUNTIES FROM 21Z THIS AFTERNOON TO 21Z
FRIDAY, ALTHOUGH GREATEST POTENTIAL OF HEAVY RAIN IS ROUGHLY
FROM EARLY THIS EVENING THROUGH MID MORNING SUNDAY. GIVEN THE
ABOVE EVOLUTION, THE FAR NORTH/NORTHWEST PORTIONS OF THE FLOOD
WATCH MAY BE AT A BIT LOWER CONFIDENCE LEVEL FOR FLOODING RAINS
GIVEN INCREASING SIGNALS THAT THE FAVORED DEFORMATION FORCING
AXIS MAY RESIDE FROM SOUTHWEST PORTIONS OF THE FORECAST AREA
THROUGH FAR NE IN. DID EXCLUDE NW OH COUNTIES AS PART OF THE
INITIAL FLOOD WATCH ISSUANCE, BUT AN EASTWARD EXTENSION OF THE
WATCH MAY BE NEEDED AT SOME POINT. ONE MITIGATING FACTOR TO
FLOOD POTENTIAL TONIGHT COULD BE RELATIVELY DRY ANTECEDENT
CONDITIONS, BUT IF HIGHER RAINFALL RATES ARE ABLE TO ANCHOR IN
DEFORMATION REGION TONIGHT, THIS WILL STILL LIKELY LEAD TO SOME
FLOODING ISSUES FOR A PORTION OF THE AREA.
STRENGTH OF DEFORMATION SHOULD TEND TO WEAKEN SUNDAY
AFTERNOON/EVENING AS RESPONSIBLE MID/UPPER LEVEL TROUGH BEGINS TO
BECOME ATTENUATED AND MORE SHEARED. CONDITIONS SHOULD DRY OUT FROM
NE TO SE LATER SUNDAY AFTERNOON INTO SUNDAY EVENING WITH A QUIETER
WEATHER PATTERN THROUGH TUESDAY AS A LONGWAVE MID/UPPER LEVEL RIDGE
SHIFTS ACROSS ONTARIO AND THE WESTERN GREAT LAKES. AN ACTIVE SERIES
OF PACIFIC WAVES ACROSS SOUTH CENTRAL CANADA/DAKOTAS WILL DAMPEN
THIS RIDGE MIDDLE OF THE WEEK WITH LOCAL AREA POSSIBLY IN A FAVORED
THETA-E GRADIENT REGION FOR PERIODIC WAVES IN WEST-NORTHWEST UPPER
FLOW FOR ADDITIONAL SHOWER/STORM CHANCES THROUGH MUCH OF THE LONG
TERM PERIOD.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 125 PM EDT SAT AUG 1 2026
A VIGOROUS VORT MAX AND A STACKED LOW PRESSURE SYSTEM MOVES
SOUTHEASTWARD TO SOUTHERN IN FROM WESTERN IL DURING THIS TAF PERIOD,
WHICH IS A SLOW PACE. A THETA-E PLUME PIVOTS EASTWARD ESPECIALLY
THROUGH SOUTHERN PARTS OF THE FORECAST AREA BRINGING THE POTENTIAL
FOR FLOODING AS WELL AS REDUCED FLIGHT CONDITIONS. MVFR CONDITIONS
TODAY, ESPECIALLY UNDER RAIN, COLLAPSE TO LOW MVFR AND IFR AFTER 00Z
TONIGHT. GIVEN CLOUD COVER, FELT MORE COMFORTABLE INCLUDING SHOWERS,
BUT NOT AS COMFORTABLE INCLUDING THUNDERSTORM POTENTIAL. IT IS
POSSIBLE THAT MVFR VISBY DIPS INTO IFR IF THUNDERSTORMS DO
MATERIALIZE. HEAVIEST RAIN MOVES THROUGH THIS AFTERNOON AND TONIGHT
BEFORE SLOWLY DEPARTING THROUGH THE DAY SUNDAY.
IWX WATCHES/WARNINGS/ADVISORIES
IN...FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR INZ005>009-012>015-
017-018-020-022>027-032>034-103-104-116-203-204-216.
BEACH HAZARDS STATEMENT THROUGH MONDAY MORNING FOR INZ103.
OH...NONE.
MI...BEACH HAZARDS STATEMENT THROUGH MONDAY MORNING FOR MIZ277.
BEACH HAZARDS STATEMENT FROM SUNDAY AFTERNOON THROUGH MONDAY
MORNING FOR MIZ177.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT MONDAY FOR LMZ043-046.
DISCUSSION...MARSILI
AVIATION...ROLLER
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