086
FXUS63 KIWX 141040
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
640 AM EDT TUE APR 14 2026
KEY MESSAGES
- A COMPLEX OF SHOWERS AND THUNDERSTORMS WILL SHIFT SOUTHEAST
ACROSS THE SOUTHERN GREAT LAKES THIS MORNING BRINGING A
POTENTIAL OF SOME GUSTY WINDS AND BRIEF HEAVY RAIN. SOME
UNCERTAINTY PERSISTS WITH HOW FAR SOUTHEAST THIS BAND OF
SHOWERS AND THUNDERSTORMS WILL SURVIVE THIS MORNING.
- ISOLATED STORMS ARE POSSIBLE THIS AFTERNOON, ESPECIALLY ACROSS NORTHWEST
INTO PORTIONS OF NORTH CENTRAL IN. HOWEVER GREAT CHANCES OF
THUNDERSTORMS WILL BE THIS EVENING INTO THE EARLY MORNING
HOURS WEDNESDAY. THERE IS A SLIGHT RISK OF SEVERE STORMS
TONIGHT WITH DAMAGING WIND GUSTS TO 60 MPH AND HAIL TO 1 TO 2
INCHES IN DIAMETER AS PRIMARY THREATS. AN ISOLATED TORNADO IS
POSSIBLE, BUT OF LOWER CONFIDENCE.
- LOCALLY HEAVY RAINFALL IS POSSIBLE TONIGHT INTO WEDNESDAY WHICH
MAY RESULT IN SOME RENEWED AREAL AND RIVER FLOODING CONCERNS.
- ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO THIS FIRST PART OF
WEEKEND BEFORE A COLD FRONT BRINGS BELOW NORMAL TEMPERATURES.
DISCUSSION
ISSUED AT 322 AM EDT TUE APR 14 2026
A COMPLICATED FORECAST OVER THE NEXT 72 HOURS WITH SEVERAL ROUNDS OF
CONVECTION POSSIBLE. SEVERE WEATHER IS POSSIBLE EACH DAY THROUGH
THURSDAY, WITH GREATEST CONFIDENCE IN SCATTERED SEVERE STORMS
TONIGHT.
A CONVECTIVE COMPLEX IS ONGOING THIS MORNING ACROSS WISCONSIN TO THE
LAKE MICHIGAN VICINITY WITH AN ASSOCIATED OUTFLOW BOUNDARY
EXTENDING FROM NORTHEAST IOWA TO FAR SOUTHEAST WISCONSIN. THIS
CONVECTIVE SYSTEM HAS SHOWN SIGNS OF BOTH DOWNWIND PROPAGATION
(EASTWARD ACROSS EAST CENTRAL WISCONSIN) AND UPWIND PROPAGATION
(SOUTHEASTWARD ACROSS SOUTH CENTRAL WISCONSIN). A STRONG LOW
LEVEL JET FEEDING INTO THIS BOUNDARY SHOULD HELP SUSTAIN
ADDITIONAL CONVECTION AND SOUTHEAST PUSH OF THE OUTFLOW TO
SOUTHERN LAKE MICHIGAN THIS MORNING. THE TENDENCY OVER NEXT FEW
HOURS MAY BE FOR INCREASING TREND IN STRONGER CORES TO BE
DISPLACED FURTHER BEHIND OUTFLOW BOUNDARY DUE TO SOME STRONGER
DOWNSTREAM MLCIN ACROSS THE SOUTHERN GREAT LAKES. MAY NEED TO
WATCH FOR POTENTIAL OF ISOLATED SEVERE GUST ACROSS PRIMARILY
SOUTHERN LOWER MICHIGAN THIS MORNING WHERE MORE OF A FORWARD
PROPAGATION MAY BE FAVORED, BUT A HIGHER CONFIDENCE POTENTIAL
DOES EXIST ACROSS NW IN/SOUTHERN LOWER MI FOR SOME 40+ MPH WIND
GUSTS THIS MORNING. THERE HAVE BEEN SOME INSTANCES OF SMALL
SCALE CIRCULATIONS DEVELOPING AT LEADING EDGE OF THE LINE ACROSS
SE WISCONSIN IN QLCS TYPE SETUP. IF FORWARD PROPAGATING SYSTEM
CAN REACH SOUTHERN LOWER MICHIGAN THIS MORNING CANNOT COMPLETELY
RULE OUT SIMILAR EVOLUTION WHERE WESTERLY 30-35 KNOT 0-3 KM
SHEAR VECTOR HAS A MORE FAVORABLE ORIENTATION, BUT MORE LIMITED
INSTABILITY WITH SOUTHWARD EXTENT AND MORE LIKELY MORE PARALLEL
ORIENTATION OF SHEAR VECTORS TO LINE THROUGH TIME MAY LIMIT
THIS POTENTIAL.
ANOTHER THING TO MONITOR FOR TODAY COULD BE POSSIBILITY OF SOME
SMALL SCALE CONVECTIVELY ENHANCED SHORT WAVE KICKING NORTHEAST
OUT OF EASTERN MISSOURI THIS MORNING WHICH COULD INTERACT WITH
THE SOUTHWARD DROPPING OUTFLOW BOUNDARY ACROSS NORTHEAST OR EAST
CENTRAL ILLINOIS. TIMING OF THIS INTERACTION WOULD PROBABLY BE
LATE MORNING/MIDDAY PERIOD IN UNFAVORABLE TIMING IN TERMS OF
PEAK DIURNAL INSTABILITY, BUT MAY NEED TO WATCH FOR SOME UPTICK
IN CONVECTION ACROSS FAR WEST/SOUTHWEST LATE MORNING GIVEN STEEP
MID LEVEL LAPSE RATES IN PLACE.
OVERALL FORECAST THINKING HAS NOT CHANGED GREATLY FOR THE PRIMARY
SEVERE WEATHER THREAT PERIOD TONIGHT. THE OUTFLOW BOUNDARY WILL
LIKELY STALL FROM NE ILLINOIS INTO PORTIONS OF IWX FORECAST AREA
THIS MORNING, WITH INSTABILITY RECOVERY LIKELY BY LATE
AFTERNOON AS THIS INSTABILITY GRADIENT IS ADVECTED BACK
NORTHWARD VIA STRONGER LOW/MID LEVEL FLOW ASSOCIATED WITH
CONVECTIVELY ENHANCED SHORT WAVES TO THE SOUTHWEST. SOME
ISOLATED STRONGER STORMS ARE POSSIBLE IN VICINITY OF THIS
INSTABILITY GRADIENT AS IT LIFTS NORTH, BUT THE POSSIBILITY
EXISTS FOR WEAK CIN TO HOLD.
BY THIS EVENING LOW LEVEL FLOW WILL BACK SOME TO THE SOUTHWEST
IN RESPONSE TO A PROGRESSIVE WAVE ACROSS WORKING ACROSS THE
UPPER MIDWEST. THIS SHOULD YIELD A POCKET OF STRONG 925-850 MB
MOISTURE CONVERGENCE FROM EASTERN IA INTO SOUTHERN WI THIS
EVENING WHICH LOOKS PRIME FOR CONVECTION INITIATION. SOME LOWER
CONFIDENCE STILL PERSISTS IN HOW CONVECTION WILL EVOLVE TONIGHT,
WHETHER A COHERENT COLD POOL AND SOUTHEAST PROPAGATING
CONVECTIVE SYSTEM OCCURS, OR IF STORMS REMAIN JUST SLIGHTLY
ELEVATED NORTH OF THE COMPOSITE BOUNDARY. SUPERCELL WIND
PROFILES WILL LIKELY BE IN PLACE AGAIN BY THIS EVENING AS A
STRONGER MID LEVEL JET LIFTS ACROSS NORTHEAST IL LATE AFTERNOON
WITH A WIND/HAIL THREAT. BEST COMBINATION OF SHEAR/INSTABILITY
STILL LOOKS POSSIBLE ACROSS NW IN/SW LOWER MI WHERE ALL SEVERE
HAZARDS WOULD APPEAR MORE LIKELY, ALTHOUGH HELICITY PROFILES
MORE FAVORABLE FOR TORNADOES MAY BE DISPLACED WEST ACROSS
NORTHERN IL WHERE SHEAR MAY BE AUGMENTED BY THE LOW/MID LEVEL
JET. AS MENTIONED, STILL UNCERTAINTY WITH DETAILS IN CONVECTIVE
MODE TONIGHT, BUT OVERALL KEY THEMES FROM PREVIOUS FORECAST
REMAIN INTACT. SOME HEAVY RAIN POTENTIAL MAY MATERIALIZE LATER
TONIGHT AS POTENTIAL OUTFLOW WITH SOUTHERN GREAT LAKES STORMS
COULD BECOME MORE FAVORABLY ORIENTED PARALLEL TO VEERING LOW
LEVEL WESTERLY FLOW.
IT IS DIFFICULT TO GET INTO TOO MUCH DETAIL REGARDING SEVERE
POTENTIAL FOR WED/THU AS THIS BE HIGHLY DEPENDENT ON PREVIOUS DAY'S
CONVECTIVE EVOLUTION AND HARD TO RESOLVE SMALLER INDIVIDUAL
SMALLER SCALE WAVES IN THIS PATTERN. THIS SITUATION IS A
COMPLEX ONE AS STUBBORNNESS OF LONGWAVE RIDGING TO BREAK DOWN
ACROSS EASTERN CONUS RESULTS IN MULTIPLE UPSTREAM SHORT WAVES
SHEARING OUT AS THEY ENCOUNTER THIS RIDGE, AND ALSO AN ADDED
INCREASED SUSCEPTIBILITY TO CONVECTIVELY ENHANCED SHORT WAVES
FROM SOUTHERN PLAINS/LOWER MS VALLEY. INSTABILITY PROFILES WILL
LIKELY BE MORE LIMITED FOR WEDNESDAY AND THURSDAY, ALTHOUGH AT
LEAST WEDNESDAY SHOULD STILL FEATURE RESPECTABLE WIND SHEAR
PROFILES THAT COULD ALLOW FOR AT LEAST AN ISOLATED SEVERE
THREAT. SOME SMALL INCREASE IN INSTABILITY IS POSSIBLE THURSDAY
AS UPPER RIDGE FINALLY APPEARS TO BE BROKEN DOWN BY STRONGER MID
LEVEL WAVE, BUT SHEAR PROFILES MAY BECOME A BIT MORE MARGINAL BY
THIS TIME.
THE EXTENDED PERIOD OF ABOVE NORMAL TEMPERATURES WILL CONTINUE
THROUGH THE FIRST PART OF THE WEEKEND. MEDIUM RANGE GUIDANCE IS
STARTING TO COME INTO A LITTLE BETTER AGREEMENT IN TIMING FRONTAL
PASSAGE WITH NEXT MORE SUBSTANTIAL LONGWAVE TROUGH FOR FIRST PART OF
THE WEEKEND. MUCH TOO EARLY FOR DETAILS, BUT SOME STRONG/SEVERE
THREAT COULD ACCOMPANY FRONTAL CONVECTION SATURDAY DEPENDING ON
TIMING. MAY ALSO NEED TO WATCH FOR PERIODS OF STRONG SYNOPTIC WINDS
THIS WEEKEND IN BOTH PRE-FRONTAL AND POST-FRONTAL ENVIRONMENTS.
COOLER, BELOW NORMAL TEMPERATURES SHOULD BUILD IN FOR SECOND HALF OF
WEEKEND INTO NEXT MONDAY, BUT RESIDENCE TIME OF THIS COOLER AIR
LOOKS TO BE LIMITED.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 628 AM EDT TUE APR 14 2026
AN OUTFLOW BOUNDARY FROM THE ORGANIZED CONVECTIVE COMPLEX ACROSS
WISCONSIN HAS LOST MUCH OF ITS MOMENTUM THIS MORNING ACROSS
NORTH CENTRAL INDIANA. AN ADDITIONAL CONVECTIVELY ENHANCED
SHORT WAVE LIFTING OUT OF NORTHERN MISSOURI WILL LIKELY INTERACT
WITH THIS LINGERING OUTFLOW FOR ADDITIONAL STORMS IN VICINITY
OF THE BOUNDARY AND IN A MORE ELEVATED SENSE BEHIND IT. THIS
GREATER PRECIP THREAT SHOULD DIMINISH LATE MORNING/MIDDAY.
THERE IS A POTENTIAL FOR AN ISOLATED STORM ALONG THE OLD OUTFLOW
BOUNDARY THIS AFTERNOON, ALTHOUGH SOME CAPPING AND WEAKER LARGE
SCALE FORCING SHOULD LIMIT THIS OVERALL THREAT. IT STILL
APPEARS AS THOUGH FAVORED CONVECTIVE INITIATION SHOULD OCCUR
ACROSS NRN IL/SRN WI LATER TONIGHT AND LIKELY PROPAGATING INTO
NORTHERN INDIANA LATE EVENING. STILL SOME UNCERTAINTY PERSISTS
REGARDING CONVECTIVE MODE AND WHETHER STORMS MAY DEVELOP A COLD
POOL AND SINK SOUTH, OR REMAIN MAINLY CONFINED ACROSS FAR
NORTHERN INDIANA FOR MUCH OF THE NIGHT. GIVEN THIS UNCERTAINTY
WILL KEEP PROB30 TSRA MENTION GOING AT THIS FORECAST DISTANCE.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR LMZ043-
046.
DISCUSSION...MARSILI
AVIATION...MARSILI
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