857
FXUS63 KIWX 211045
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
645 AM 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.
- THE SEVERE RISK IS LOW BUT A FEW STRONG STORMS CAN'T BE RULED
OUT SOUTH OF HIGHWAY 24.
- HIGH WAVES AND DANGEROUS CURRENTS ARE EXPECTED ON LAKE
MICHIGAN BEACHES MONDAY.
- THE REST OF THE WEEK WILL FEATURE SLIGHTLY BELOW NORMAL
TEMPERATURES AND PERIODIC CHANCES FOR LIGHT RAIN.
DISCUSSION
ISSUED AT 254 AM EDT SUN JUN 21 2026
CONVECTIVELY MODIFIED SHORTWAVE(S) CURRENTLY MOVING THROUGH THE
CENTRAL PLAINS WILL CONTINUE EASTWARD TODAY AND IMPACT OUR AREA THIS
EVENING/OVERNIGHT. SOME RIGHT ENTRANCE UPPER JET DYNAMICS AND
EJECTING MCV WILL SUPPORT MODEST SURFACE CYCLOGENESIS WITH A 40+ KT
LLJ NOSING INTO OUR SOUTHERN CWA. UNFORTUNATELY, THE EXACT DETAILS
REMAIN MURKY EVEN LESS THAN 24 HOURS OUT DUE TO COMPLICATIONS FROM
MULTIPLE UPSTREAM MCS'S. CLUSTER OF CONVECTION CURRENTLY OVER KS/NE
IS EXPECTED TO EJECT EASTWARD THROUGH THE MORNING (FUELED BY STEADY
LLJ/MOISTURE CONVERGENCE) AND CAPITALIZE ON SOME MODEST
DESTABILIZATION SOUTH OF I-70 THIS AFTERNOON. THIS CLUSTER OF
CONVECTION WILL SWEEP ACROSS INDIANA DURING THE EVENING HOURS BUT
THE EXACT TRACK REMAINS UNCERTAIN AS DOES THE EXACT LOCATION OF THE
ALL-IMPORTANT SURFACE FRONTAL BOUNDARY. BULK OF GUIDANCE KEEPS THIS
SURFACE BOUNDARY AND ASSOCIATED SEVERE RISK JUST SOUTH OF OUR CWA.
HOWEVER, STILL SOME MEMBERS SUGGESTING IT WILL SNEAK INTO OUR FAR
SOUTHERN COUNTIES. STILL THINK THE SEVERE RISK IS LOW. WHILE
SHEAR/HELICITY VALUES ARE SUPPORTIVE OF A SEVERE RISK, MIDLEVEL
LAPSE RATES ARE VERY POOR AND SURFACE DEWPOINTS ARE ONLY AROUND 60F
(EVEN SOUTH OF THE FRONT). EVEN THE NORTHWARD-DISPLACED MODELS (3KM
NAM) STILL SHOW AWFULLY STABLE PROFILES IN THE LOWEST 3-5 KFT THAT
WILL BE DIFFICULT TO SUPPORT ANY DAMAGING WIND/TORNADO RISK. OUR FAR
SOUTH (SOUTH OF US-24) STILL BEARS SOME WATCHING THIS EVENING BUT A
LOT OF FACTORS WOULD HAVE TO COME TOGETHER TO YIELD A SEVERE RISK
AND THE CHANCES OF THAT APPEAR LOW AT THIS POINT. WE WILL CONTINUE
TO MONITOR UPSTREAM CONVECTION CLOSELY THROUGH THE MORNING THOUGH.
THE OTHER ASPECT TO THIS EVENT WILL BE THE POTENTIAL FOR SOME
MODERATE-HEAVY RAIN. HERE AGAIN, IMPORTANT MESOSCALE DETAILS REMAIN
UNRESOLVED. MY SUSPICION IS THAT A PROGRESSIVE MCS JUST TO OUR SOUTH
WILL ROB BETTER MOISTURE FROM OUR CWA, AS SUGGESTED BY SOME OF THE
LATEST CAM'S, KEEPING RAINFALL AMOUNTS GENERALLY AROUND AN INCH OR
PERHAPS EVEN LESS. HOWEVER, SOME ELEVATED DEFORMATION/FGEN ORIENTED
PARALLEL TO THE MEAN FLOW COULD SET UP THE POTENTIAL FOR SOME
TRAINING MODERATE RAIN EVEN IN OUR NORTHERN ZONES. ALSO, THE BETTER
MOISTURE/INSTABILITY AND MCS TRACK COULD STILL SNEAK INTO FAR S/SE
ZONES. DEEP WARM CLOUD LAYERS AND PW VALUES NEAR 2" CERTAINLY BEAR
WATCHING AND COULD SUPPORT ISOLATED POCKETS OF HEAVY RAIN/MINOR
FLOODING BUT 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", EVEN WITH POCKETS OF AROUND 2".
SCT, 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. SHORTWAVE
RIDGING/SUBSIDENCE YIELDS ONE DRY/PLEASANT DAY ON TUE BUT ANOTHER
TROUGH BRINGS MORE LIGHT RAIN CHANCES LATE WED INTO THU AND AGAIN
LATE FRI INTO SAT (PERHAPS SOME HEAVIER RAIN WITH THAT ONE). HIGHS
REMAIN IN THE UPPER 70S/NEAR 80 UNTIL FINALLY A STRONG RIDGE
DEVELOPS NEXT WEEKEND AND PUSHES HIGHS BACK TO NEAR 90 TO END THE
MONTH.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 645 AM EDT SUN JUN 21 2026
SHORTWAVE EJECTS INTO THE REGION TONIGHT AND BRINGS WIDESPREAD
RAIN, MVFR CEILINGS, AND A FEW EMBEDDED THUNDERSTORMS. THE BEST
CHANCE FOR STORMS WILL BE AT KFWA WHERE BETTER MOISTURE AND
INSTABILITY RESIDE. BEST THUNDER CHANCES APPEAR TO BE ROUGHLY
01-05Z BUT THAT TIMING COULD STILL CHANGE. IFR CEILINGS ARE
ALSO EXPECTED AT KFWA AFTER 06Z AS COOLER AIR FILTERS INTO THE
AREA AND COMBINES WITH VERY MOIST LOW LEVELS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...AGD
AVIATION...AGD
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page