084
FXUS63 KIND 130600
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
200 AM 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
- A FEW SEVERE THUNDERSTORMS ARE POSSIBLE TODAY WITH DAMAGING WIND
GUSTS AS A STORM COMPLEX MOVES IN FROM THE WEST
- ADDITIONAL STORM CHANCES CONTINUE FRIDAY INTO SATURDAY
- WARMER AND MORE HUMID CONDITIONS RETURN SATURDAY BEFORE DRIER AND
COOLER WEATHER SETTLES IN SUNDAY THROUGH EARLY NEXT WEEK
MESOSCALE UPDATE
ISSUED AT 200 AM EDT THU AUG 13 2026
THUNDERSTORMS HAVE RECENTLY DEVELOPED NORTH OF A QUASI-
STATIONARY FRONT OVER SOUTHWESTERN INDIANA WITH A COMPLEX OF SLOW
MOVING STORMS ORIENTED NORTHWEST TO SOUTHEAST FROM VIGO TO MARTIN
COUNTIES. RECENT COOLING CLOUD TOP TRENDS SUGGESTS THE POTENTIAL FOR
UPSCALE GROWTH OVER THE NEXT COUPLE OF HOURS. THE ACTIVITY IS
FOCUSING ALONG AN INSTABILITY GRADIENT, WITH MUCAPE VALUES OF 1000
TO 2000 J/KG. WARM AIR ADVECTION AND A CONVERGENT 20 TO 30 KT WEST-
SOUTHWEST LOW-LEVEL JET.
THIS IS SUPPORTED BY SOME OF THE LATEST HI-RES GUIDANCE, ALTHOUGH
THERE IS SOME SPATIAL SPREAD WITH THE DETAILS AND CERTAINLY THE
AMOUNTS.THE LATEST RADAR AND SATELLITE TRENDS COUPLED WITH PWS BEING
UP AROUND 1.75 INCHES SUGGEST SOME LOCALIZED 2 INCH/HOUR RAINFALL
RATES CONTINUE TO BE POSSIBLE THROUGH DAYBREAK.
THIS WILL SUPPORT SOME SPOTTY RAINFALL AMOUNTS THROUGH EARLY THIS
MORNING OF 2 TO 4 INCHES AND MAY REQUIRE ADDITIONAL AREAL/FLASH
FLOOD WARNINGS THROUGH THE MORNING HOURS. THIS AREA DID NOT SEE THE
HEAVY RAIN YESTERDAY, SO 3-6 HOUR FFG REMAINS GENERALLY AT OR AROUND
2-3 INCHES.
DISCUSSION (TODAY THROUGH WEDNESDAY)
ISSUED AT 116 AM EDT THU AUG 13 2026
OVERVIEW.
WARM AND HUMID WEATHER CONTINUES TODAY ACROSS CENTRAL INDIANA WITH
ADDITIONAL SHOWERS AND THUNDERSTORMS. HEAVY RAINFALL WILL LEAD TO A
CONTINUED THREAT FOR FLASH FLOODING, PARTICULARLY ACROSS NORTH
CENTRAL INDIANA TOWARDS THE OVERNIGHT WHERE SLOW MOVING STORMS ARE
LIKELY TO BRING ADDITIONAL VERY HEAVY RAIN. A FEW STORMS COULD ALSO
PRODUCE STRONG TO DAMAGING WIND GUSTS DURING THE AFTERNOON AND
EVENING HOURS. RAIN CHANCES PERSIST INTO FRIDAY AND SATURDAY AS A
FRONTAL SYSTEM MOVES THROUGH THE REGION. TEMPERATURES WILL BRIEFLY
WARM INTO THE UPPER 80S AND LOWER 90S ON SATURDAY AND SUNDAY BEFORE
A COLD FRONT PUSHES THROUGH. BEHIND THIS FRONT, HIGH PRESSURE WILL
BRING A STRETCH OF DRIER, LESS HUMID, AND PLEASANT WEATHER FROM
MONDAY THROUGH WEDNESDAY.
THURSDAY AND FRIDAY.
CENTRAL INDIANA REMAINS POSITIONED ALONG THE NORTHEASTERN
PERIPHERY OF A BROAD UPPER-LEVEL RIDGE CENTERED OVER THE SOUTH-
CENTRAL US, MAINTAINING NW FLOW ALOFT WITH EMBEDDED SHORTWAVES
TRAVERSING THE REGION. AT THE SURFACE, A QUASI-STATIONARY
CONVECTIVE OUTFLOW BOUNDARY RESTS ACROSS SOUTHERN CENTRAL INDIANA.
LATEST ACARS SOUNDINGS SHOW AN UNSEASONABLY MOIST ATMOSPHERIC
PROFILE WITH PWAT VALUES RANGING FROM 2.00 TO 2.25 INCHES,
EXCEEDING THE 90TH PERCENTILE FOR MID-AUGUST. HIGH MOISTURE
CONVERGENCE ALONG THE BOUNDARY COMBINED WITH DEEP WARM-CLOUD LAYER
DEPTHS GREATER THAN 4000 METERS WILL DRIVE HIGH PRECIPITATION
EFFICIENCY AND WARM RAIN PROCESSES. HREF PROBABILITY-MATCHED MEAN
GUIDANCE HIGHLIGHTS ISOLATED 2 TO 4 INCH QPF AMOUNTS WHERE CELL
TRAINING OCCURS. GIVEN ANTECEDENT LOW FFG VALUES FROM RECENT
CONVECTIVE ROUNDS, A FLOOD WATCH REMAINS IN EFFECT ACROSS MOST OF
CENTRAL INDIANA
THERMODYNAMICALLY, DIURNAL HEATING WILL YIELD SBCAPE VALUES OF 1500
TO 2500 J/KG, THOUGH POOR MID-LEVEL LAPSE RATES OF 5.5 TO 6.0 C/KM
WILL LIMIT THE HIGHER END THREAT FOR SEVERE WEATHER. HOWEVER,
EFFECTIVE BULK SHEAR OF 30 TO 35 KTS COUPLED WITH DCAPE VALUES NEAR
800 TO 1000 J/KG WILL SUPPORT ORGANIZED CELL CLUSTERS AND SHORT
BOWING SEGMENTS. DAMAGING STRAIGHT-LINE WINDS DRIVEN BY CONVECTIVE
DOWNDRAFTS REMAIN THE PRIMARY SEVERE THREAT THROUGH THURSDAY
EVENING. THE MAIN THREAT LOOKS TO BE DURING THE LATE EVENING AND
EARLY OVERNIGHT HOURS WHEN ANOTHER QUASI-STATIONARY COMPLEX OF
SHOWERS AND STORMS LOOKS TO IMPACT CENTRAL INDIANA WITH THE
POTENTIAL ADDITIONAL FLASH FLOODING. THE EXACT LOCATION OF THIS AXIS
REMAINS UNCERTAIN, BUT CONFIDENCE IS HIGHEST IN A NORTHWEST TO
SOUTHEAST BAND FROM APPROXIMATELY ALONG TO SLIGHTLY NORTH OF THE I-
74 CORRIDOR. BROADLY, MUCH OF CENTRAL INDIANA IS LIKELY TO SEE 1-2.5
INCHES BUT WITHIN THIS AXIS THERE WILL BE THE POTENTIAL FOR POCKETS
OF 3-6 INCHES.
ON FRIDAY, ANOTHER SUBTLE SHORTWAVE MOVING THROUGH THE UPPER MIDWEST
WILL INDUCE LOW-LEVEL WARM AIR ADVECTION AND A STRENGTHENING LLJ OF
25-35KTS. THE SURFACE FRONT THAT HAS HELPED TO DRIVE RAIN CHANCES
WILL BECOME SUBTLE ENOUGH TO NO LONGER BE A FACTOR IN PRECIPITATION
WITH ANY SHOWERS AND STORMS INSTEAD BEING DRIVEN BY THE SHORTWAVE
ALOFT. OVERALL, CHANCES ARE FAIRLY LOW OUTSIDE OF ANY RESIDUAL
BOUNDARIES FROM THURSDAYS CONVECTION.
SATURDAY THROUGH WEDNESDAY.
MODELS HAVE BEEN TRENDING TO A WEAKER RIDGE OVER THE CENTRAL PLAINS
WHICH WILL KEEP THE PATTERN ACTIVE OVER THE OHIO VALLEY AS THE JET
STREAM WON'T BE SHUNTED TO THE NORTH FURTHER INTO THE GREAT LAKES.
SOUTHWESTERLY BOUNDARY-LAYER ADVECTION WILL HELP PUSH SURFACE
TEMPERATURES INTO THE UPPER 80S AND LOWER 90S. HIGH DEWPOINTS IN THE
MID-70S WILL YIELD HEAT INDICES APPROACHING 100 DEGREES ACROSS
SOUTHERN COUNTIES. A NORTHERN STREAM UPPER-LEVEL TROUGH OVER CANADA
WILL SWEEP A SURFACE COLD FRONT ACROSS THE GREAT LAKES AND OHIO
VALLEY SUNDAY INTO MONDAY. CONVECTIVE INITIATION IS EXPECTED ALONG
THE FRONT AS MLCAPE REACHES 1500 TO 2000 J/KG AMID 30 TO 40 KTS OF 0-
6 KM BULK SHEAR. MULTICELL LINES CAPABLE OF STRONG WIND GUSTS AND
BRIEF HEAVY RAIN WILL ACCOMPANY THE COLD FRONTAL PASSAGE.
AS THE SURFACE COLD FRONT EXITS TO THE SOUTH, ALLOWING A ~1020 MB
SURFACE HIGH PRESSURE SYSTEM TO BUILD SOUTHWARD FROM THE CANADIAN
PRAIRIES INTO THE GREAT LAKES. ADVECTION OF AIR FROM THE NORTHWEST
WILL HELP TO BRING DRIER AND SLIGHTLY COOLER AIR INTO THE AREA LATE
MONDAY THROUGH WEDNESDAY WITH BROADLY QUIET WEATHER.
AVIATION (06Z TAF ISSUANCE)
ISSUED AT 116 AM EDT THU AUG 13 2026
IMPACTS:
- MVFR/IFR CONDITIONS POSSIBLE IN FOG AND STRATUS THROUGH DAYBREAK
- MORE WIDESPREAD TSRA POSSIBLE THURSDAY AFTERNOON, POTENTIAL FOR
HEAVY RAIN DURING THE OVERNIGHT TOWARDS LAF
DISCUSSION:
SOME PARTIAL CLEARING OF CLOUDS, LESSENING WIND, AND WET GROUND FROM
RECENT RAINS WILL LEAD TO FOG/STRATUS DEVELOPMENT THROUGH DAYBREAK.
EXPECT MOST OF IT TO OCCUR FROM 09Z TO 12Z. IFR AND WORSE IS LIKELY
AT KLAF, WITH MVFR AND POTENTIALLY WORSE ELSEWHERE. FOG WILL MIX OUT
BY 14Z.
RAIN COVERAGE THROUGH DAYBREAK WILL LIKELY REMAIN LIMITED TO JUST
HUF WITH LOWER CHANCES AT IND AND BMG. RAIN COVERAGE THEN SHOULD BE
FAIRLY LOW THROUGH THE DAY BEFORE A COMPLEX OF STORMS MOVES IN FROM
THE WEST DURING THE AFTERNOON. TRAINING STORMS THEN ARE LIKELY
TONIGHT TOWARDS LAF WITH THE POTENTIAL FOR AN EXTENDED PERIOD OF
MVFR TO IFR VSBYS.
IND WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH FRIDAY MORNING FOR INZ021-028>031-035>049-
051>057-060>065-069>072.
MESOSCALE...WHITE
AVIATION...WHITE
DISCUSSION...WHITE
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