181
FXUS63 KIND 161740
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
ISSUED BY NATIONAL WEATHER SERVICE LOUISVILLE KY
140 PM EDT SUN AUG 16 2026
..UPDATED AVIATION DISCUSSION
KEY MESSAGES
- ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THIS
AFTERNOON WITH LIGHT RAIN AMOUNTS POSSIBLE.
- HEAT INDEX VALUES IN EXCESS OF 100 POSSIBLE TODAY IN SOUTHERN
PORTIONS OF CENTRAL INDIANA
- DRY AND MILDER WEATHER EARLY IN THE WORK WEEK
- ADDITIONAL STORMS POSSIBLE WEDNESDAY
FORECAST UPDATE
ISSUED AT 922 AM EDT SUN AUG 16 2026
SURFACE ANALYSIS THIS MORNING LOW PRESSURE IN PLACE OVER EASTERN LK
SUPERIOR, WITH A WEAK TROUGH OF LOW PRESSURE STRETCHING SOUTH TO
INDIANA AND WESTERN KY THIS MORNING. ALOFT, WATER VAPOR IMAGERY
SHOWS A PLUME OF TROPICAL MOISTURES STRETCHING FROM THE AMERICAN
SOUTHWEST ACROSS THE CENTRAL PLAINS TO THE GREAT LAKES AND INDIANA.
A CONVECTIVE CLUSTOR WAS FOUND OVER NE MO, MOVING EAST WITHIN THE
FLOW AND APPEARED TO BE DIURNALLY WEAKENING WITH WARMING CLOUD TOPS.
RADAR SHOWS AN AREA OF SCATTTERED LIGHT SHOWERS ASSOCIATED WITH THE
TROUGH, GENERALLY PRODUCING LIGHT PRECIPITATION. ADDITIONAL LIGHT
SHOWERS EXTENDED WEST TOWARD HUF AND CENTRAL IL AND EASTERN MO.
GIVEN THE UPPER FLOW, THESE APPEAR POISED TO PASS ACROSS CENTRAL
INDIANA THROUGH THE AFTERNOON. DEW POINTS ACROSS CENTRAL INDIANA
REMAINED QUITE MISERABLE, IN THE MIDDLE 70S.
FORCEAST SOUNDINGS THROUGH THE AFTERNOON SHOW A MOIST AND NEARLY
SATURATED COLUMN FROM TIME TO TIME. THE SURFACE TROUGH IS EXPECTED
TO SLOWLY PUSH EAST AS SURFACE FLOW REMAINS WESTERLY. THIS SHOULD
ALLOW EASTERN PROPAGATION OF THE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS TO PUSH ACROSS CENTRAL INDIANA THROUGH THE AFTERNOON.
HRRR SHOWS THE SHOWERS WEAKENING THROUGH THE NEXT SEVERAL HOURS, BUT
DOES RE-ESTABLISH ISOLATED CONVECTIVE DEVELOPMENT THIS AFTERNOON AS
DAYTIME HEATING ALLOWS HIGH TO REACH THE UPPER 80S. THUS WE WILL
KEEP SOME CHC POPS IN THE FORECAST FOR SHOWERS THAT ARE CAPABLE OF
PRODUCING LOW RAIN FALL AMOUNTS. ANY ADDITIONAL RAINFALL AMOUNTS
TODAY WILL HAVE LITTLE TO NO IMPACT ON ONGOING FLOODIND AS HEAVY
RAIN IS NOT EXPECTED.
DISCUSSION (TODAY THROUGH SATURDAY)
ISSUED AT 303 AM EDT SUN AUG 16 2026
THROUGH TONIGHT...
ONE OR MORE UPPER LEVEL WAVES, AT LEAST PARTIALLY CONVECTIVELY-
ENHANCED, WILL TRAVERSE THE AREA THIS MORNING INTO TONIGHT, WITH
ATTENDANT THREATS FOR ADDITIONAL SHOWERS AND THUNDERSTORMS. MODEST
BUT SUFFICIENT DEEP LAYER SHEAR WILL REMAIN IN PLACE, ALONG WITH
AMPLE INSTABILITY IN THE CONTINUED WARM AND VERY MOIST ENVIRONMENT.
AREAS OF LOW LEVEL CONVERGENCE ASSOCIATED BOTH WITH SURFACE
BOUNDARIES AND REMNANT CONVECTIVE OUTFLOWS WILL SERVE AS FOCI FOR
DEVELOPMENT, BUT GIVEN THE COMPLEX SITUATION AND CAM STRUGGLES WITH
PLACEMENT AND CONSISTENCY RUN-TO-RUN, CONFIDENCE IS LOWERED.
LOCALIZED DAMAGING WIND GUSTS WILL REMAIN THE PRIMARY SEVERE THREAT.
NEEDLESS TO SAY, FLASH FLOOD CONCERNS WILL REMAIN THE MOST PRESSING
WORRY, HOWEVER. HREF LOCAL PROBABILITY MATCHED MEANS SUGGEST A
THREAT FOR UP TO A 1-2+ INCHES OF RAIN WITH THE MOST INTENSE STORMS,
WHICH WILL CONTINUE TO POSE A EXTREMELY RAPID ONSET FLASH FLOOD
THREAT, THOUGH THERE IS SOME GUIDANCE SUGGESTION THAT THE HEAVIER
RAINFALL THREAT MAY BE MORE CENTRAL AND SOUTH, WHICH, WHILE STILL
QUITE WET, IS NOT QUITE IN AS ROUGH A SHAPE AS AREAS FROM INDY METRO
NORTH AND NORTHEAST.
MONDAY AND TUESDAY...
AN AREA OF SURFACE HIGH PRESSURE WILL MERCIFULLY BRING AT LEAST A
TEMPORARY END TO THE REPEATED ROUNDS OF THUNDERSTORMS EARLY IN THE
WEEK, WITH DRY WEATHER AND NEAR NORMAL TEMPERATURES LIKELY EARLY
MONDAY INTO TUESDAY.
TUESDAY NIGHT INTO WEDNESDAY NIGHT...
UNFORTUNATELY, AN ADDITIONAL ROUND OF THUNDERSTORMS APPEARS LIKELY
LATE TUESDAY NIGHT INTO WEDNESDAY NIGHT AS ANOTHER COLD FRONT AND
UPPER LEVEL WAVE ACCOMPANYING A STRONG JET STREAK ALOFT PASSES
THROUGH THE REGION. PLENTIFUL MOISTURE WILL BE AVAILABLE, THOUGH
PRECIPITABLE WATER VALUES MAY BE SLIGHTLY MORE MODEST (70-80TH
PERCENTILE CLIMATOLOGICALLY). HOWEVER, SOMEWHAT STRONGER DEEP LAYER
SHEAR MAY BE AVAILABLE. ANOTHER ROUND OF SEVERE STORMS WILL
CERTAINLY BE POSSIBLE, THOUGH PREDICTABILITY IS GREATLY LIMITED
GIVEN THE SENSITIVITY TO PRIOR ROUNDS OF STORMS AND MODEL
INCONSISTENCIES 4 DAYS OUT.
THAT SAID, EVEN WITH A COUPLE OF DAYS TO DRY OUT, FLASH FLOOD
VULNERABILITY WILL REMAIN QUITE HIGH IN THE FACE OF ANY ADDITIONAL
CONVECTIVE RAINFALL GIVEN THE EXTREME ANTECEDENT CONDITIONS, AND WE
WILL NEED TO REMAIN VIGILANT THROUGH AT LEAST MID WEEK FOR THESE
CONCERNS.
THURSDAY ONWARD...
AMPLIFICATION OF THE UPPER RIDGE OVER THE WESTERN CONUS AND
SOUTHWARD DISPLACEMENT OF BOTH THE FRONTAL ZONE AND DEEPER MOISTURE
BY SURFACE HIGH PRESSURE AND UPPER LEVEL TROUGHING SUGGEST MILDER
TEMPERATURES AND MOSTLY DRY CONDITIONS LATE WEEK AND INTO THE
WEEKEND, THOUGH SOME SLIGHT CHANCES FOR SHOWERS OR STORMS MAY LINGER
ACROSS THE SOUTHERN PORTIONS OF CENTRAL INDIANA. IT WILL TAKE QUITE
SOME TIME FOR ANTECEDENT CONDITIONS TO SIGNIFICANTLY IMPROVE,
UNFORTUNATELY, AND ANY ADDITIONAL CONVECTIVE RAINFALL WITH PERIODIC
FRONTAL PASSAGES OR UPPER LEVEL WAVES IN THE BROADER CYCLONIC FLOW
NEXT WEEKEND AND INTO THE FOLLOWING WEEK WILL POSE AT LEAST MODEST
FLASH FLOOD THREATS.
AVIATION (18Z TAF ISSUANCE)
ISSUED AT 138 PM EDT SUN AUG 16 2026
ONE MORE CLUSTER OF SHOWERS AND STORMS IS PUSHING THROUGH THE
HUF/BMG TERMINALS OVER THE NEXT 1 TO 2 HOURS. BRIEF VIS REDUCTIONS
POSSIBLE ALONG WITH GUSTY/VARIABLE WINDS IN T-STORM ACTIVITY IS
POSSIBLE. OTHERWISE, SHOULD BE MOSTLY DRY AND VFR THROUGH THE
REMAINDER OF THE AFTERNOON AND EVENING. CAN'T RULE OUT A STRAY LIGHT
SHOWER THROUGH THE LATE AFTERNOON AND EARLY EVENING AND HAVE
MENTIONED PROB30 TO ACCOUNT FOR THAT.
LATER TONIGHT, ANOTHER CLUSTER OF THUNDERSTORMS IS EXPECTED TO
DEVELOP AND MOVE ALONG AND SOUTH OF THE I-70 CORRIDOR. THIS PUTS
IND/HUF/BMG AT RISK OF MORE T-STORM ACTIVITY AND HAVE HIGHLIGHTED
THE BEST EXPECTED TIME FRAME IN THIS ISSUANCE. A WEAK COLD FRONT
PASSES N TO S IN THE MORNING HOURS OF SUNDAY WITH WINDS VEERING NW
TO N. SOME LOW CLOUDS AND PERHAPS SOME FOG COULD BE AROUND IN THE
PRE-DAWN HOURS, HOWEVER THINGS SHOULD THE DEEPER INTO THE DAY WE GET.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...PUMA
AVIATION...BJS (WFO LMK)
DISCUSSION...NIELD
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