033
FXUS63 KIWX 131848
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
248 PM EDT MON APR 13 2026
KEY MESSAGES
- THE POTENTIAL FOR MULTIPLE ROUNDS OF SHOWERS AND STORMS,
POSSIBLY STRONG TO SEVERE, EXIST THROUGH THURSDAY. THE MOST
LIKELY PERIOD APPEARS TO BE TUESDAY NIGHT INTO THURSDAY, BUT
CONFIDENCE REMAINS ON THE LOWER SIDE WITH FINER DETAILS
REGARDING IMPACTS AND INTENSITY.
- HYDRO CONCERNS COULD INCREASE FOR MID TO LATE WEEK DEPENDING
ON TRACKS OF SUCCESSIVE CONVECTIVE ROUNDS.
- ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO THIS WEEKEND.
DISCUSSION
ISSUED AT 238 PM EDT MON APR 13 2026
CHALLENGING NEAR AND SHORT TERM FORECAST THROUGH TUESDAY NIGHT
AND EVEN INTO WEDNESDAY WITH A SERIES OF MID LEVEL AND
CONVECTIVELY INDUCED DISTURBANCES EXPECTED TO TRANSVERSE THE
REGION. CERTAINTY IS HIGHEST IN PLENTY OF MOISTURE AND
INSTABILITY (STEEP MID-LEVEL LAPSE RATES AND SBCAPE OF 1K TO 2K
J/KG) AROUND FOR ANY OF THESE WAVES. CERTAINTY DROPS
CONSIDERABLY WITH REGARDS TO TIMING AND IMPACTS OF WHAT COULD BE
MULTIPLE ROUNDS OF CONVECTION IN SOME AREAS. AS A RESULT, HARD
TO MAKE ANY LARGER, WHOLESALE CHANGES TO THE FORECAST INTO
TUESDAY AS WE WAIT TO SEE HOW THINGS EVOLVE. WILL BREAK THINGS
DOWN AS BEST AS I CAN.
TO KICK THINGS OFF, WE ARE CLOSELY MONITORING A MID LEVEL
DISTURBANCE MOVING THROUGH WESTERN IL WITH AN AREA OF SHOWERS AND
STORMS ATTEMPTING TO SLOWLY EXPAND WHICH MAY IMPACT WEST/NORTHWEST
AREAS NEAR/AFTER 20Z. CAMS ARE ALL OVER THE PLACE ON EVOLUTION (OR
LACK THEREOF) OF THIS AREA OR POSSIBLY SEPARATE DEVELOPMENT LATER
THIS AFTERNOON OR EVENING. AS NOTED ABOVE PARAMETERS FAVOR AT LEAST
A THREAT OF STG-SVR STORMS WITH HAIL AND MAYBE GUSTY WINDS BECOMING
A THREAT WITH THE STRONGER ACTIVITY. WILL MAINTAIN SLGT CHC TO CHC
POPS FOR NOW AND ADJUST AS NEEDED BASED ON TRENDS. SOME SOLUTIONS
ALSO SHOW DEVELOPMENT CLOSER TO 00Z WITH A WEST TO EAST BAND OF
CONVECTION IMPACTING NORTHERN AREAS. THIS SEEMS LESS PLAUSIBLE
AT THIS POINT, BUT CANNOT BE ENTIRELY DISCOUNTED WITH BOTH A
SEVERE AND POSSIBLY HYDRO THREAT OCCURRING.
CONFIDENCE IS HIGH ON DEVELOPMENT OF STG-SVR STORMS ACROSS PORTIONS
OF MN AND WI IN A VERY FAVORABLE ENVIRONMENT THIS EVENING
(SWODY1 ENHANCED RISK OUTLINES THIS). MUCH LIKE THE NEAR TERM
PERIOD, CAMS DIFFER CONSIDERABLY ON HOW THIS AREA EVOLVES WITH
SOME SOLUTIONS TRACKING THE ACTIVITY DUE EAST AND OTHERS
SUGGESTING A SE PROPAGATION TOWARDS US LATE TONIGHT INTO EARLY
TUESDAY WITH POTENTIAL STG-SVR STORMS AND POSSIBLY SOME HYDRO
ISSUES (ALTHOUGH THIS SHOULD BE RATHER PROGRESSIVE). AGAIN,
LIMITED CHANGES TO POPS FOR THE TIME BEING.
OVERNIGHT CONVECTION WILL PLAY SOMEWHAT OF A FACTOR WRT THE THREAT
FOR SEVERE STORMS TUE AFTERNOON-EARLY WED. ISOLATED STORMS COULD
DEVELOP DURING THE AFTERNOON AND EARLY EVENING HOURS ON ANY
LINGERING BOUNDARIES, BUT THE GREATEST FOCUS WILL START TO OUR WEST
ACROSS EASTERN IA/N IL/S WI DURING THE AFTERNOON HOURS AND THEN
POSSIBLY EXPANDING EAST AND CONTINUING TO ORGANIZE. AGAIN, CAM
SOLUTIONS ON THE EVOLUTION OF THIS INTO OUR AREA ARE ALL OVER THE
PLACE, BUT SIGNALS ARE STRONGEST FOR AT LEAST SOME CONVECTION
TUESDAY NIGHT INTO EARLY WEDNESDAY WITH BOTH A SEVERE AND HYDRO
THREAT QUITE POSSIBLE. THE NEW SPCDY2 OUTLOOK REMAINS UNCHANGED WITH
THE EASTERN EDGE OF AN ENHANCED RISK TO OUR IMMEDIATE W AND N, WITH
THE AREA IN A SLIGHT RISK FOR MAINLY A HAIL AND WIND THREAT. NOT
GOING TO EVEN TRY TO MAKE MANY UPDATES AT THIS POINT.
THE ACTIVE WEATHER CONTINUES WEDNESDAY INTO THURSDAY AS A SOMEWHAT
STRONGER TROUGH PUSHES INTO THE AREA, WITH MODELS SOMEWHAT IN
AGREEMENT ON MORE WIDESPREAD SHOWERS AND STORMS WITH MAYBE MORE OF A
HYDRO VS SEVERE THREAT. THE AREA IS PRESENTLY IN A MARGINAL RISK OF
SEVERE AND EXCESSIVE RAINFALL RISK. WITH ALL THE CHALLENGES, NOT
EVEN GOING TO TRY TO MAKE CHANGES THAT FAR OUT.
IN THE WAKE OF THE TROUGH, ONE MORE PUSH OF WARM AIR COMMENCES WITH
HIGHS FRIDAY WELL INTO THE 70S AND MAYBE SOME 80S. SHOWER/STORM
CHANCES WILL INCREASE LATE FRIDAY NIGHT INTO SATURDAY AHEAD OF AN
EVEN STRONGER TROUGH THAT WILL EVENTUALLY SEND TEMPS BACK CLOSER TO,
IF NOT NORMAL SUNDAY.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 118 PM EDT MON APR 13 2026
A GENERAL TREND TO VFR CEILINGS IS ANTICIPATED FOR THE
AFTERNOON, BUT CANNOT COMPLETELY DISCOUNT A ROGUE BKN MVFR
CEILING AMID FAIR-WEATHER CUMULUS. THE MAIN QUESTION OF THIS
TAF PERIOD IS HOW DO ANY THUNDERSTORMS EVOLVE THIS AFTERNOON AND
WHAT IMPACT DOES THAT HAVE FOR THE REST OF THE TAF PERIOD.
GIVEN THE VERY HIGH PWATS, HAVE OPTED TO BRING THE VISIBILITY
DOWN TO IFR FOR TSRA. STORMS ARE TRYING TO REMAIN ORGANIZED
ACROSS ILLINOIS. OUR LOCAL ENVIRONMENT APPEARS WELCOMING TO
THESE STORMS. AT THIS STAGE, KSBN APPEARS THE BEST CANDIDATE TO
SEE TSRA, WHILE KFWA WOULD WAIT UNTIL TONIGHT. CONFIDENCE IS
UNUSUALLY LOW FOR THESE NEXT 24 HOURS GIVEN A LACK OF MODEL
CONSISTENCY AND MURKY MESOSCALE FACTORS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...FISHER
AVIATION...BROWN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page