853
FXUS63 KIND 140234
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1034 PM EDT THU AUG 13 2026
KEY MESSAGES
- HEAVY RAIN AND LOCALIZED FLASH FLOODING REMAIN THE PRIMARY CONCERN
TODAY, ESPECIALLY ACROSS NORTH CENTRAL INDIANA INTO THE OVERNIGHT.
- CONTINUED RAIN TONIGHT AND ON FRIDAY WILL WORSEN AN ALREADY
VERY SIGNIFICANT FLOODING EVENT.
- A FEW SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON WITH DAMAGING
WIND IS GUSTS AS A STORM COMPLEX MOVES IN FROM THE WEST
- ADDITIONAL STORM CHANCES CONTINUE FRIDAY INTO SATURDAY AS A WARM
FRONT LIFTS NORTH FOLLOWED BY A COLD FRONT OVER THE WEEKEND
- WARMER AND MORE HUMID CONDITIONS RETURN SATURDAY BEFORE DRIER AND
COOLER WEATHER SETTLES IN SUNDAY THROUGH EARLY NEXT WEEK
FORECAST UPDATE
ISSUED AT 1034 PM EDT THU AUG 13 2026
RAIN COOLED AIR COVERS MUCH OF CENTRAL INDIANA THIS EVENING WITH
TEMPERATURES IN THE LOWER TO MIDDLE 70S AND DEWPOINTS IN THE 70S. A
SURFACE BOUNDARY REMAINS ACROSS NORTHERN PORTIONS OF THE FORECAST
AREA, WITH NORTHEAST WINDS TO THE NORTH OF THE BOUNDARY AND
SOUTHEAST WINDS SOUTH OF THE BOUNDARY.
THE ATMOSPHERE REMAINS QUITE MOIST WITH 00Z ILX AND ILN SOUNDINGS
SHOWING PRECIPITABLE WATER VALUES BETWEEN 1.75 AND 2 INCHES.
INCREASING 850MB FLOW WILL INTERACT WITH THE SURFACE BOUNDARY TO THE
NORTH TO AID IN CONVECTIVE DEVELOPMENT. SOME UPPER ENERGY WILL ADD
ADDITIONAL FORCING. WILL GO HIGH POPS ACROSS THE NORTHERN FORECAST
AREA OVERNIGHT WITH LOWER POPS TO THE SOUTH.
ELEVATED INSTABILITY REMAINS DECENT. THIS ALONG WITH DECENT SHEAR
WILL KEEP THE THREAT FOR SOME SEVERE STORMS DURING THE NIGHT AS
WELL.
THE MAIN CONCERN WILL BE HEAVY RAIN AND FLASH FLOODING. CAMS CAN
SOMETIMES STRUGGLE AND PRODUCE VERY HIGH RAINFALL AMOUNTS WITH
NOCTURNAL EVENTS, AND THE 00Z HRRR SHOWS AMOUNTS OVER 4 INCHES IN
THE NORTHERN FORECAST AREA BY 12Z. MEANWHILE THE 01Z IS LOWER AND
FARTHER NORTHWEST WITH THE HIGHEST AMOUNTS. THUS, CAMS CANNOT BE
TAKEN LITERALLY AS THEY CHANGE FROM RUN TO RUN. THEY CAN SHOW AREAS
TO WATCH FOR THOUGH.
HOWEVER, THE 12Z HREF AND REFS LOCAL PROBABILITY MATCHED MEANS SHOW
THE THREAT FOR HEAVY RAINFALL OVER THE NORTHERN FORECAST AREA
INCLUDING THE HARDEST HIT AREAS FROM PREVIOUS RAINS. EVEN A COUPLE
OF INCHES IN THE HARDEST HIT AREAS WILL HAVE SIGNIFICANT IMPACT.
HAVE CONTINUED MESSAGING OF THE THREAT FOR ADDITIONAL HEAVY RAINFALL
AND ADDITIONAL/WORSENING FLOODING.
DISCUSSION (THIS EVENING THROUGH THURSDAY)
ISSUED AT 227 PM EDT THU AUG 13 2026
SURFACE ANALYSIS THIS AFTERNOON SHOWS A TROUGH AXIS ACROSS
CENTRAL IL TO THE NORTHERN PARTS OF CENTRAL INDIANA. THE CONVECTIVE
COMPLEX HAS ADVANCED TO CENTRAL IL. RADAR SHOWS A FEW SCATTERED
THUNDERSTORMS AHEAD OF THIS LINE PUSHING ACROSS EASTERN IL. DEW
POINTS HAVE SURGED TO THE 70S, BUT TEMPERATURES HAVE BEEN A BIT SLOW
TO RISE DUE TO CLOUD COVER.
TONIGHT...
UNCERTAINTY EXIST WITH HE PROGRESSION OF THE THUNDERSTORM CLUSTER
OVER IL. THIS SYSTEM APPEARS TO BE MOVING IN TO A LESS FAVORABLE
ENVIRONMENT, DUE TO MORNING CLOUDS, BUT WITH THE AFTERNOON HEATING,
THE ENVIRONMENT IS BECOMING MORE FAVORABLE FOR CONTINUED PROGRESSION
TO THE ESE.
THE CONTINUED NW FLOW ALOFT AND ANOTHER SHORT WAVE ARE EXPECT
OVERNIGHT. THIS WILL GENERATE SHOWERS AND THUNDERSTORM ONCE AGAIN
OVERNIGHT. MODELS SHOW FAVORABLE ISENTROPIC LIFT SETTING UP AHEAD OF
THE SHORT WAVE OVERNIGHT PARTICULARLY ALONG AND NORTH OF LAF TO
RUSHVILLE AXIS. GIVEN OUR VERY HIGH DEW POINTS SHOWERS AND STORMS
WILL BE EFFICIENT RAIN PRODUCERS AND 1-2 INCHES OF RAIN WITH
ISOLATED HIGHER AMOUNTS CANNOT BE RULED OUT. FORECAST SOUNDINGS SHOW
A SATURATED COLUMN WITH VERY HIGH PWATS OVER 2.2 INCHES OVERNIGHT.
ADDITIONAL RAINFALL OVER ALREADY FLOODED AREA MAY WORSEN THE
SITUATION. THUS WILL BE USING HIGH POPS TONIGHT, FOCUSING THE BEST
TIMING FROM MID EVENING THROUGH 08Z.
FRIDAY AND FRIDAY NIGHT...
MODELS CONTINUE TO SUGGEST RIDGING RIDING FORCING DYNAMICS
CONTINUING TO PASS ACROSS CENTRAL INDIANA ON FRIDAY, WITH THE
FAVORABLE AIR MASS STILL IN PLACE ALONG WITH THE TROUGH AXIS SLOWLY
MOVING SOUTH ACROSS INDIANA. FORECAST SOUNDINGS ON FRIDAY REMAIN
SATURATED WITH VERY PWATS STILL ABOVE 2 INCHES AS LIFT AND
INSTABILITY REMAIN IN PLACE. THUS WILL CONTINUE HIGH POPS THROUGH
THE DAY AGAIN ON FRIDAY AND FRIDAY NIGHT, WITH BEST CHANCES TO
REMAIN ALONG AND NEAR AND I-74 CORRIDOR.
SATURDAY AND SATURDAY NIGHT...
FORECAST SOUNDINGS ARE SHOWN TO DRY OUT ON SATURDAY AND SATURDAY
NIGHT AS CONVECTIVE TEMPERATURES BECOME UNREACHABLE. HOWEVER A VERY
WARM AND HUMID AIR MASS WILL REMAIN IN PLACE WHICH MAY RESULT IN
NEED FOR A HEAT ADVISORY AS MID 90S WILL BE POSSIBLE. MODELS HINT
THAT THE BEST FORCING PATH WILL PUSH TO THE NORTH AND MORE LIMITED
EMBEDDED WAVES LOOK TO PASS. THUS SHOULD THERE BE ANY DIURNAL
CONVECTION, BEST CHANCES WOULD BE ACROSS THE ALREADY SOAKED NORTHERN
PARTS OF THE FORECAST AREA.
SUNDAY AND SUNDAY NIGHT...
RAIN CHANCES LOOK TO PERSIST ON SUNDAY AS A COLD FRONT WILL PUSH
ACROSS CENTRAL INDIANA THOUGH THE AFTERNOON AND INTO THE EVENING.
UPPER LEVELS SUGGEST A CONTINUED WNW FLOW WITH A WEAK SHORT WAVE
PASSING THROUGH THE AFTERNOON TO PROVIDE FORCING. WARM AND HUMID AIR
WILL BE IN PLACE AHEAD OF THIS SYSTEM. THUS PLENTY OF FACTORS IN
PLAY TO SUPPORT POPS. COLD FRONT IS SUGGESTED TO SAG SOUTHWARD TO
THE OHIO RIVER BY LATE SUNDAY NIGHT AND PRECIP SHOULD END NEAR THAT
TIME.
MONDAY THROUGH THURSDAY...
MODELS SUGGEST CONTINUE WNW FLOW IN PLACE ALOFT DURING THIS TIME,
BUT LITTLE IN THE WAY OF FORCING DYNAMICS APPEAR TO BE IN PLAY.
MEANWHILE DURING THIS TIME, COOLER HIGH PRESSURE IN THE WAKE OF
SUNDAY'S COLD FRONT WILL BE PUSHING ACROSS INDIANA AND THROUGH THE
REGION. THIS WILL LEAD TO LOWER DEWPOINTS AND COOLER HIGHS. FORECAST
SOUNDINGS SHOW A DRY COLUMN THROUGH WEDNESDAY MORNING AS THESE
FEATURES PASS.
ON WEDNESDAY AFTERNOON AND INTO THURSDAY THE SURFACE HIGH WILL BE
DEPARTING TO THE SOUTHEAST. THIS WILL ALLOW ANOTHER SURFACE BOUNDARY
OVER THE GREAT LAKES TO SAG SOUTHWARD ACROSS INDIANA AT THIS TIME.
BY THIS TIME, SOUTHERLY RETURN FLOW WILL HAVE ALLOWED WARMER AND
MORE HUMID AIR TO ARRIVE ACROSS CENTRAL INDIANA. FURTHERMORE, THE
FLOW ALOFT LOOKS TO BECOME MORE NW AS RIDGING OVER THE WESTERN US
BECOMES MORE AMPLIFIED. ALTHOUGH THE SIGNAL FOR EMBEDDED WAVES
WITHIN THIS FLOW IS UNCLEAR AT THIS TIME, GIVEN THE PATTERN,
EMBEDDED WAVES PROVIDING FORCING APPEARS PLAUSIBLE. THUS POPS AND
WARMER TEMPERATURES WILL BE USED.
AVIATION (00Z TAF ISSUANCE)
ISSUED AT 732 PM EDT THU AUG 13 2026
IMPACTS:
- MAINLY VFR CONDITIONS EXPECTED FOR MOST OF THIS EVENING, AND
AGAIN BY FRIDAY AFTERNOON.
- SHOWERS AND THUNDERSTORMS DEVELOPING AFTER 04Z NORTH OF
I-74/I-69 SPREADING SOUTHWARD OVERNIGHT. IFR VISIBILITIES AND
MVFR CEILINGS LIKELY WITH THESE STORMS.
DISCUSSION:
VFR FLIGHT CONDITIONS WILL PREVAIL FOR MOST OF THIS EVENING IN THE
WAKE OF THIS AFTERNOON'S THUNDERSTORMS. ANOTHER ROUND OF STORMS IS
EXPECTED TO DEVELOP LATE THIS EVENING OVER NORTHERN INDIANA, AND
MOVE SOUTHWARD OVERNIGHT. IFR VISIBILITIES IN HEAVY RAIN AND MVFR
CEILINGS ARE LIKELY WITH THESE STORMS. THE LOWER CEILINGS COULD
PERSIST OUTSIDE OF STORMS INTO THE MORNING. AREAS ALONG AND NORTH
OF I-70 WILL HAVE THE BEST CHANCE FOR LINGERING CEILINGS AT OR
BELOW 3000 FEET FRIDAY, THOUGH IT'S POSSIBLE THE LOWER CEILINGS
COULD GET FARTHER SOUTH. SCATTERED SHOWERS MAY ALSO LINGER INTO
THE DAYLIGHT HOURS OF FRIDAY MORNING. LOW CEILINGS SHOULD LIFT AND
SCATTER BY EARLY FRIDAY AFTERNOON.
IND WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH FRIDAY EVENING FOR INZ021-028>031-035>049-
051>057-060>065-069>072.
UPDATE...50
AVIATION...CARNEY
DISCUSSION...PUMA
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