334
FXUS63 KIND 241749
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
149 PM EDT THU SEP 24 2026
KEY MESSAGES
- COOLER THAN AVERAGE CONDITIONS PERSIST TODAY WITH MOSTLY CLOUDY
SKIES.
- CLEARING SKIES WITH A WARMING TREND THIS WEEKEND.
- SHOWERS AND THUNDERSTORMS POSSIBLE LATE TUESDAY THROUGH EARLY
THURSDAY.
DISCUSSION (THIS EVENING THROUGH THURSDAY)
ISSUED AT 149 PM EDT THU SEP 24 2026
REST OF TODAY AND TONIGHT
THE OVERALL SYNOPTIC SETUP REMAINS SIMILAR
OVER THE AREA WITH A SURFACE HIGH OVER SE CANADA AND AN UPPER LOW
JUST TO THE SE. COLD, MOIST ADVECTION ALONG THE COLD CONVEYOR BELT
ALONG WITH MODEST SUBSIDENCE HAS KEPT OVERCAST SKIES OVER THE OHIO
VALLEY FOR MUCH OF THE DAY. THERE IS SOME MID LEVEL DRY AIR WORKING
ITS WAY INTO THE AREA THIS AFTERNOON WHICH HAS ALLOWED FOR SOME
MIXING AND POCKETS OF CLEARING. THAT SAID, BROAD CLEARING LIKELY
WONT ARRIVE UNTIL LATE THIS EVENING INTO THE OVERNIGHT AS DRY AIR
ENTRAINMENT INCREASES ON THE NORTHERN END OF THE UPPER LOW OCCLUSION
ALONG WITH HIGH PRESSURE BUILDING IN FROM THE NE. CLEARING WILL BE A
SLOW PROCESS, BUT SHOULD GRADUALLY MOVE THROUGH CENTRAL BEWEEN 02Z
AND 08Z FROM EAST TO WEST.
TEMPERATURES OVERNIGHT WILL HAVE A MODEST GRADIENT ACROSS THE AREA
DUE TO THIS TEMPORAL DIFFERENCE IN CLEARING. SOME AREAS OVER FAR NE
CENTRAL INDIANA WHERE CLEARING IS EXPECTED TO BEGIN MAY HAVE ENOUGH
DIURNAL COOLING TO REACH THE MID 40S BY DAY BREAK. THE REST OF THE
AREA SHOULD SEE LOWS NEAR TO JUST ABOVE 50. SOME MODELS ARE
MAINTAINING CLOUD COVER OVER THE SOUTHERN WABASH VALLEY AS PRESSURE
GAINS WANE WITH THE LOW MOVING OFF TO THE EAST. IF THIS OCCURS, LOWS
MAY ONLY BRIEFLY FALL BELOW 60 OVER W/SW PORTIONS OF THE AREA. I
SURFACE HIGH PRESSURE, CENTERED OVER SOUTHEASTERN CANADA, HAS BE
FRIDAY THROUGH SUNDAY
FOR TOMORROW, A NEW BROAD AREA OF LOW PRESSURE BEGINS TO DEVELOP
OVER THE MISSISSIPPI VALLEY LEADING TO AN ADDITIONAL SOURCE OF CLOUD
COVER OVER CENTRAL INDIANA. LOW CLOUDS ARE LIKELY TO BE MUCH LESS
ABUNDANT, BUT UPPER LEVEL CIRRUS WILL LIKELY PUSH THROUGH THE AREA
THROUGHOUT THE DAY LEADING TO OPAQUE, MOSTLY CLOUDY SKIES. THERE IS
SOME UNCERTAINTY WITH HOW THICK THE CIRRUS SHIELD WILL BE, AND
THEREFOR ITS IMPACT ON HIGH TEMPERATURES, GENERALLY THE EXPECTATION
IS FOR HIGHS IN THE LOW 70S, BUT AREAS WITH THINNER CIRRUS MAY PUSH
INTO THE MID 70S TOMORROW AFTERNOON.
HIGH PRESSURE WILL CONTINUE TO BUILD WITHIN EASTERLY FLOW TOMORROW
INTO THE WEEKEND, CREATING GREATER SUBSIDENCE OVER THE AREA. THIS
SHOULD KEEP THE BRAOD REGION OF LOW PRESSURE TO THE WEST, EVENTUALLY
RESULTING IN MOSTLY CLEAR SKIES OVER THE WEEKEND ONCE CIRRUS DEBRIS
LEAVES THE AREA. DIURNAL CUMULUS IS LIKELY OVER WESTERN PORTIONS OF
THE AREA, WITH GRADUAL TEMPERATURE GAINS EACH DAY. THS WILL LEAD TO
A VERY SEASONAL LATE SEPTEMBER WEEKEND ACORSS THE AREA. GREATER
DIURNAL COOLING ALONG WITH LINGERING SURFACE MOISTURE FRIDAY NIGHT
MAY LEAD TO PATCHY DENSE FOG, BUT UNCERTAINTY IS TOO HIGH TO INLUDE
AT THIS TIME.
NEXT WEEK
GUIDANCE IS BEGINNING TO HINT AT A POTENT SYSTEM DEVELOPING OVER THE
PLAINS AROUND THE TUESDAY TIMEFRAME. CURRENT ENSEMBLE SUITE
GENERALLY BRINGS THE LOW CENTER TO OUR NORTHWEST, WITH THE TRAILING
COLD FRONT PASSING THROUGH INDIANA. UNCERTAINTY REMAINS REGARDING
THE STRENGTH AND TRACK OF THE LOW, BUT ENOUGH OF A SIGNAL IS PRESENT
TO JUSTIFY HIGHER POPS TUESDAY NIGHT THROUGH EARLY THURSDAY.
THUNDERSTORMS ARE ALSO POSSIBLE, BUT DEEP WARM MOIST ADVECTION
APPEARS LIMITED DESPITE THE SYSTEM'S POTENTIAL STRENGTH. FOR NOW,
MOST MEMBERS OF GUIDANCE SHOW ONLY LOW AMOUNTS OF MLCAPE (UNDER 500
J/KG). THIS SYSTEM RESEMBLES A COLD-SEASON SYNOPTIC LOW WITH MINIMAL
INSTABILITY AND HIGH SHEAR. SO, DESPITE THE LOW MLCAPE, THIS SYSTEM
STILL BEARS WATCHING FROM A SEVERE WEATHER STANDPOINT.
AVIATION (18Z TAF ISSUANCE)
ISSUED AT 112 PM EDT THU SEP 24 2026
IMPACTS:
- MVFR CEILINGS THROUGH 02Z
DISCUSSION:
IFR CEILINGS ARE BEGINNING TO LIFT WITH MOSTLY MVFR CEILINGS NOW
ACROSS CENTRAL INDIANA. THAT SAID, THERE STILL MAY BE POCKETS OF IFR
CEILINGS THROUGH 19Z. SOME BREAKS IN THE CLOUDS MAY ALLOW FOR
TEMPORARY VFR CONDITIONS THROUGHOUT THE AFTERNOON AND EVENING, BUT
OTHERWISE EXPECT MVFR CEILINGS TO PERSIST UNTIL 02Z TONIGHT BEFORE
CLEARING FROM EAST TO WEST ACROSS THE STATE. KHUF AND KLAF WILL
LIKELY BE THE LAST TO CLEAR TONIGHT INTO TOMORROW MORNING.
WINDS SHOULD REMAIN OUT OF THE NE/ENE THROUGHOUT THE TAF PERIOD,
MAINLY BETWEEN 7-10KT WITH SLIGHT LULLS OVERNIGHT.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
AVIATION...UPDIKE
DISCUSSION...UPDIKE/ECKHOFF
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