410
FXUS63 KIWX 132310
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
710 PM EDT TUE OCT 13 2026
KEY MESSAGES
- A COLD FRONT WILL GRADUALLY SAG SOUTHWARD ACROSS THE AREA
TONIGHT INTO WEDNESDAY LEADING TO SCATTERED SHOWERS AND SOME
EMBEDDED THUNDERSTORMS. SEVERE WEATHER IS NOT EXPECTED
TONIGHT OR WEDNESDAY.
- A LULL IN GREATER RAIN CHANCES IS EXPECTED LATER WEDNESDAY AFTERNOON
INTO WEDNESDAY NIGHT, BUT ANOTHER ROUND OF SHOWERS AND STORMS
IS EXPECTED THURSDAY AND THURSDAY NIGHT.
- THERE IS A MARGINAL RISK OF SEVERE STORMS (MAINLY WIND) ALONG
AND SOUTH OF US ROUTE 24 FOR THURSDAY EVENING. CONFIDENCE IN
SEVERE WEATHER IS LOW.
- TURNING MUCH COOLER AND WINDY FOR FRIDAY WITH SOME LAKE EFFECT
RAIN SHOWERS.
DISCUSSION
ISSUED AT 305 PM EDT TUE OCT 13 2026
THE SHORT WAVE TROUGH AND PRE-FRONTAL FORCING WHICH AIDED IN SHOWERS
ALONG AND SOUTH OF THE US ROUTE 24 CORRIDOR EARLIER TODAY WILL
CONTINUE TO SHIFT ACROSS THE EASTERN GREAT LAKES REGION THIS
EVENING. ISOLATED SHOWERS AND THUNDERSTORMS HAVE ALSO DEVELOPED
DURING THE MID AFTERNOON ACROSS SOUTHWEST LOWER MICHIGAN/FAR
NORTHERN INDIANA WHERE SOME INCREASE IN LOW LEVEL FRONTOGENESIS
FORCING ALLOWED DEVELOPMENT ALONG WEAK CONFLUENCE ZONE AND ALSO
JUST DOWNSTREAM OF WHAT APPEARS TO BE SOUTHWEST EXTENT OF WEAK
DPVA.
THE FOCUS FOR TONIGHT INTO EARLY WEDNESDAY WILL BE ANOTHER LOW
AMPLITUDE SHORT WAVE TROUGH EJECTING OUT OF THE DAKOTAS AND A
RESULTANT SLOW SOUTHWARD SINKING BAROCLINIC ZONE INTO
WEDNESDAY. PRECEDING THIS WAVE AND FRONTAL ZONE WILL BE ANOTHER
SURGE OF HIGHER LOW LEVEL THETA-E AIR. ISENTROPIC FORCING DOES
NOT APPEAR TO BE AS PRONOUNCED AS LAST NIGHT, BUT AXIS OF FAIRLY
STRONG LOW LEVEL FGEN FORCING AND INCREASING ELEVATED
INSTABILITY SHOULD COMPENSATE FOR THIS WITH SCATTERED SHOWERS
AND ISOLATED/SCATTERED THUNDERSTORMS EXPECTED TO REDEVELOP LATE
EVENING INTO THE OVERNIGHT HOURS. GIVEN ELEVATED NATURE OF THE
INSTABILITY, SEVERE WEATHER IS NOT EXPECTED. SOME BRIEF HEAVY
RAINFALL IS POSSIBLE GIVEN INCREASING DEPTH OF MOISTURE
PROFILES, LONG/SKINNY CAPE PROFILES, AND INCREASING WARM CLOUD
DEPTHS. GIVEN QUITE DRY ANTECEDENT CONDITIONS, SIGNIFICANT
HYDRO IMPACTS ARE NOT EXPECTED.
BY MID AFTERNOON WEDNESDAY, SCATTERED SHOWER/STORM ACTIVITY SHOULD
PROGRESSIVELY SINK SOUTHWARD AS LOW LEVEL FGEN AXIS BECOMES MORE
MUTED AND SHIFTED SOUTH. THIS WILL OCCUR AS SOME RECOVERY IN MID
LEVEL HEIGHTS OCCURS UPSTREAM IN RESPONSE TO STRONGER UPPER
TROUGH/CUT-OFF LOW FEATURE LIFTING NORTHEAST OUT OF THE FOUR CORNERS
REGION.
ANOTHER ROUND OF ACTIVE WEATHER IS EXPECTED THURSDAY AND FRIDAY AS
THE CUT-OFF UPPER LOW BEGINS TO PHASE WITH A MORE DYNAMIC NORTHERN
STREAM UPPER LEVEL TROUGH DIGGING SOUTHEAST OUT OF SOUTH CENTRAL
CANADA. THIS PHASING SYSTEM WILL LIKELY RESULT IN CYCLOGENESIS
OVERHEAD LATE THURSDAY WITH SOME FAVORABLE UPPER JET DYNAMICS
ALSO COMING INTO PLAY. THIS STRONGLY FORCED SETUP SHOULD SUPPORT
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON
AND THURSDAY NIGHT BEFORE A STRONG ACCOMPANYING COLD FRONT
SWEEPS ACROSS THE AREA. WITH THE TENDENCY TO SIGNALS OF BETTER
PHASING, SFC REFLECTION IS LIKELY TO TAKE A TRACK CLOSER TO
GUIDANCE THAT HAS BEEN ADVERTISING A NORTHERLY TRACK ACROSS
IN/NW OH/SE LOWER MI. THIS COULD PROVIDE A BRIEF TEMPORAL WINDOW
OF WEAK NEAR SURFACE BASED CAPE ACROSS AT LEAST SOUTHEAST
PORTIONS OF THE FORECAST AREA LATE THURSDAY AFTERNOON AND MORE
LIKELY THURSDAY EVENING. UNCERTAINTY REMAINS WITH JUST HOW FAR
NORTH WARM FRONTAL FEATURE CAN PROGRESS THURSDAY NIGHT BUT GIVEN
ROBUST KINEMATIC PROFILES MAY NEED TO MONITOR FOR ISOLATED
STRONG/SEVERE THREAT THURSDAY EVENING, ESPECIALLY SOUTH OF US
24. GIVEN PROGRESSION OF FEATURES AND DRY ANTECEDENT CONDITIONS,
WIDESPREAD HYDRO CONCERNS ARE NOT EXPECTED. PWATS WILL BE
HIGHLY ANOMALOUS ON THURSDAY HOWEVER, SO SOME LOCALIZED HEAVIER
RAINFALL AMOUNTS ARE POSSIBLE.
FRIDAY STILL APPEARS DISMAL WITH BLUSTERY CONDITIONS DEVELOPING ON
COLD SIDE OF THIS DEEPENING SYSTEM. PEAK AFTERNOON GUSTS INTO THE 35
TO 40 MPH RANGE STILL APPEAR POSSIBLE GIVEN DEEP POST-FRONTAL
MIXING. SOME CONSIDERATION MAY BE GIVEN TO A WIND ADVISORY
DOWNWIND OF LAKE MICHIGAN, BUT UNCERTAINTY REMAINS IN THIS
REGARD. SOME LAKE EFFECT RAIN SHOWERS WILL ALSO BE LIKELY
ALTHOUGH DURATION OF DEEPER LAKE INDUCED INSTABILITY PROFILES
APPEARS SOMEWHAT LIMITED TO FRIDAY MORNING/EARLY PM. FRIDAY AND
SATURDAY WILL FEATURE TEMPS WELL BELOW NORMAL WITH NIGHTTIME
LOWS IN THE 30S. ALONG WITH THE BETTER PHASED SYSTEM COMES THE
POTENTIAL OF A SLIGHTLY QUICKER EASTWARD PROGRESSION OF SFC
ANTICYCLONE LATE FRIDAY NIGHT WITH AN ATTENDANT FROST POTENTIAL
FRIDAY NIGHT AND SATURDAY NIGHT. FLOW DEAMPLIFICATION QUICKLY
ENSUES TO START NEXT WORK WEEK WHICH SHOULD RESULT IN
TEMPERATURES MODERATING BACK TO SLIGHTLY ABOVE NORMAL BY MONDAY-
TUESDAY.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 709 PM EDT TUE OCT 13 2026
EXISTING TAFS REMAIN ON TRACK THIS EVENING. A COLD FRONT IS
SLOWLY WORKING ITS WAY THROUGH NORTHERN INDIANA. ENCOUNTERING A
SUBTROPICAL HIGH OVER THE SOUTHEAST, A VERY WEAK PRESSURE
GRADIENT WILL RESULT IN LIGHT WIND INTO THE OVERNIGHT HOURS.
ISOLATED SHOWERS AND THUNDERSTORMS HAVE FESTERED UPSTREAM IN THE
VICINITY OF THE FRONT AND THIS ACTIVITY IS EXPECTED TO
REJUVENATE THROUGH EARLY WEDNESDAY MORNING. SHOWERS BECOME
DIVORCED FROM THE BEST UPPER-LEVEL SUPPORT BY SUNRISE WEDNESDAY
RESULTING IN A WEAKENING TREND TOWARD KFWA. HIGH PWATS CAN
LIKELY RESULT IN PERIODS OF MVFR VISIBILITY FROM ANY SHOWERS
THAT MOVE THROUGH.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...MARSILI
AVIATION...BROWN
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