895
FXUS63 KIND 150532
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
132 AM EDT THU OCT 15 2026
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS TODAY, WITH ISOLATED SEVERE STORMS
CAPABLE OF DAMAGING WINDS THIS AFTERNOON AND EVENING
- STRONG POST-FRONTAL NORTHWEST WINDS WILL GUST BETWEEN 30 AND 40
MPH ON FRIDAY
- WIDESPREAD FROST AND LOCALIZED FREEZE CONDITIONS ARE LIKELY
SATURDAY NIGHT INTO SUNDAY MORNING
DISCUSSION (TODAY THROUGH WEDNESDAY)
ISSUED AT 131 AM EDT THU OCT 15 2026
TODAY THROUGH FRIDAY.
AS OF EARLY THIS MORNING, THE FRONT THAT BROUGHT RAIN TO CENTRAL
INDIANA IS SOUTH OF THE FORECAST AREA, BUT AS THE NEXT LOW PRESSURE
SYSTEM MOVES IN FROM THE CENTRAL PLAINS LATER THIS MORNING, THAT
FRONT IS EXPECTED TO PUSH BACK TO THE NORTH. AHEAD OF THE BOUNDARY,
POLEWARD MOISTURE ADVECTION CHARACTERIZED BY AN 850 MB LOW-LEVEL JET
OF 40-50 KT WILL LIFT SURFACE DEW POINTS INTO THE LOW-TO-MID 60S,
CREATING A SHORT WINDOW IN THE MID TO LATE AFTERNOON HOURS WHERE
MLCAPE COULD REACH 750 TO 1250 J/KG ALONG AND SOUTH OF THE I-70
CORRIDOR BY EARLY AFTERNOON. KINEMATIC FIELDS ARE QUITE ROBUST, WITH
500 MB MID-LEVEL FLOW AROUND 50-60 KT YIELDING EFFECTIVE BULK SHEAR
OF 45-55 KT. THIS DEEP-LAYER SHEAR WILL FAVOR ORGANIZED MULTI-CELL
CLUSTERS AND LINEAR SEGMENTS CAPABLE OF BOWING ALONG WITH AN
INCREASING THREAT FOR A FEW DISCRETE SUPERCELLS LATE THIS AFTERNOON
INTO THE EVENING.
LOW-LEVEL 0-1 KM STORM-RELATIVE HELICITY VALUES OF 100-150 M2/S2
WILL SUPPORT AN ISOLATED BRIEF SPIN-UP ALONG THE WARM FRONT, BUT
THAT THREAT WILL BE CONDITIONAL ON THE FRONT LOCATION AND EXTENT OF
DAYTIME WARMING. THUS THE DOMINANT CONVECTIVE HAZARD WILL BE
DAMAGING STRAIGHT-LINE DOWNDRAFT WINDS UP TO 60 MPH VIA MOMENTUM
TRANSPORT WITH THE TORNADO THREAT BEING SECONDARY. HREF ENSEMBLE
MEMBERS (HRRR, FV3, AND ARW) DEPICT INITIAL CONVECTIVE DEVELOPMENT
ACROSS WEST-CENTRAL INDIANA BETWEEN 16Z AND 18Z, PROGRESSING ACROSS
THE INDIANAPOLIS METRO AREA BETWEEN 19Z AND 22Z, AND EXITING EASTERN
COUNTIES BY 01Z-02Z. QPF WILL AVERAGE BETWEEN 0.50 AND 1.25 INCHES;
LOCALIZED TRAINING COULD PRODUCE MINOR NUISANCE PONDING IN POOR
DRAINAGE AREAS, BUT THE PROGRESSIVE MOTION OF THE SYSTEM WILL
MITIGATE WIDESPREAD FLASH FLOOD CONCERNS.
THE COLD FRONT WILL PUSH SOUTHEAST OF THE FORECAST AREA BY 03Z,
BRINGING AN END TO HEAVIER PRECIPITATION WITH LINGERING LIGHT RAIN
THROUGH THE NIGHT. COLD AIR ADVECTION WILL ENSUE OVERNIGHT AS 850 MB
TEMPERATURES PLUMMET FROM +12C TO NEAR +1C BY FRIDAY AFTERNOON. THE
TIGHT PRESSURE GRADIENT BETWEEN THE DEPARTING SURFACE LOW OVER
EASTERN CANADA AND A CANADIAN HIGH BUILDING INTO THE PLAINS WILL
GENERATE EFFICIENT BOUNDARY-LAYER MOMENTUM TRANSFER. DIURNAL MIXING
INTO THE 850-800 MB LAYER WILL TAP INTO 35-40 KT AMBIENT FLOW,
SUPPORTING SUSTAINED NORTHWEST WINDS OF 18-25 MPH WITH FREQUENT
GUSTS OF 35-40 MPH FRIDAY AFTERNOON. CYCLONIC FLOW AND STEEP LOW-
LEVEL LAPSE RATES WILL FOSTER AN EXTENSIVE STRATOCUMULUS DECK,
PARTICULARLY ACROSS THE NORTHERN TWO-THIRDS OF THE CWA. HIGHS ON
FRIDAY WILL REMAIN SUPPRESSED, RANGING FROM THE UPPER 50S NORTH TO
THE LOWER 60S SOUTH. WINDS FRIDAY NIGHT SHOULD KEEP FROST FORMATION
LIMITED EVEN AS TEMPERATURES DROP INTO THE MID TO UPPER 30S, BUT
SHELTERED AREAS COULD SEE SOME FROST AHEAD OF A WIDESPREAD FROST
SATURDAY NIGHT.
SATURDAY THROUGH WEDNESDAY.
A BROAD LONGWAVE TROUGH WILL ANCHOR ACROSS THE EASTERN CONUS ON
SATURDAY AS A STRONG SURFACE ANTICYCLONE SHIFTS FROM THE UPPER
MISSISSIPPI VALLEY SOUTHEASTWARD ACROSS THE OHIO VALLEY THROUGH
SUNDAY. THE CORE OF THE COLD POOL WILL SIT OVERHEAD SATURDAY,
KEEPING 850 MB TEMPERATURES AROUND 0C TO +2C. DESPITE CLEARING SKIES
AND SUBSIDENCE, DAYTIME HIGHS ON SATURDAY WILL STRUGGLE TO REACH OUT
OF THE MID 50S, 10-15 DEGREES BELOW NORMAL.
SATURDAY NIGHT INTO SUNDAY MORNING REPRESENTS THE PRIMARY FROST AND
LOW-END FREEZE WINDOW OF THE PERIOD. THE SURFACE HIGH CENTER WILL
SETTLE DIRECTLY OVER CENTRAL INDIANA BY 09Z SUNDAY, DECOUPLING THE
BOUNDARY LAYER AND YIELDING CALM WINDS, CLEAR SKIES, AND A VERY DRY
AMBIENT AIR MASS WITH DEW POINTS IN THE UPPER 20S TO LOW 30S. STRONG
RADIATIONAL COOLING WILL CAUSE OVERNIGHT MINIMUM TEMPERATURES TO
DROP INTO THE LOWER TO MID-30S ACROSS THE ENTIRE FORECAST AREA, WITH
RURAL DRAINAGE BASINS AND TRADITIONAL COLD SPOTS LIKELY DROPPING NEAR
FREEZING. WIDESPREAD FROST IS EXPECTED ACROSS CENTRAL INDIANA, AND
FREEZE CONDITIONS ARE PROBABLE IN SHELTERED RURAL AREAS. FROST AND
FREEZE HEADLINES WILL LIKELY BE REQUIRED AS CONFIDENCE REMAINS HIGH
ACROSS DETERMINISTIC GFS, ECMWF, AND THEIR RESPECTIVE ENSEMBLE
SUITES.
THE ANTICYCLONE WILL DRIFT EASTWARD TOWARD THE MID-ATLANTIC ON
SUNDAY, ALLOWING INSOLATION TO REBOUND HIGHS INTO THE UPPER 50S AND
LOWER 60S. LOWS SUNDAY NIGHT WILL REMAIN COOL, IN THE UPPER 30S TO
LOWER 40S, WITH PATCHY FROST CONFINED TO FAR EASTERN RURAL VALLEYS
BEFORE LOW-LEVEL WINDS BACK TO THE SOUTH.
FOR MONDAY THROUGH WEDNESDAY, THE SYNOPTIC PATTERN TRANSITIONS AS
UPPER-LEVEL RIDGING BUILDS OVER THE EASTERN STATES AND A DEEP TROUGH
CARVES OUT OVER THE WESTERN CONUS. STEADY SOUTH-SOUTHWESTERLY RETURN
FLOW WILL DRIVE A SIGNIFICANT WARM AIR ADVECTION REGIME ACROSS THE
OHIO VALLEY. 850 MB TEMPERATURES WILL MODERATE TO +10C TO +13C,
PUSHING DAYTIME HIGHS INTO THE LOWER 70S ON MONDAY AND MID-70S ON
TUESDAY. OVERNIGHT LOWS WILL MODERATE INTO THE UPPER 40S TO MID-50S.
MEDIUM-RANGE GUIDANCE INDICATES AN EJECTING NORTHERN-STREAM
SHORTWAVE TROUGH WILL DRAG AN ASSOCIATED SURFACE COLD FRONT TOWARD
THE LOWER GREAT LAKES AND OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY.
MOISTURE CONVERGENCE AHEAD OF THIS BOUNDARY WILL RAISE PRECIPITABLE
WATER VALUES BACK ABOVE 1.25 INCHES, SUPPORTING CHANCE TO LIKELY
POPS FOR RAIN SHOWERS AND ISOLATED EMBEDDED THUNDERSTORMS LATE
TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON. DISPLACED UPPER-LEVEL
DYNAMIC SUPPORT AND MARGINAL INSTABILITY CURRENTLY SUGGEST A LOW
PROBABILITY OF SEVERE WEATHER WITH THIS MID-WEEK FRONTAL PASSAGE.
TEMPERATURES ON WEDNESDAY WILL RUN IN THE UPPER 60S TO LOWER 70S
AHEAD OF THE FRONT.
AVIATION (06Z TAF ISSUANCE)
ISSUED AT 131 AM EDT THU OCT 15 2026
IMPACTS:
- MVFR TO IFR CIGS ARE EXPECTED FOR MUCH OF THIS TAF PERIOD
- SHOWERS AND STORMS LIKELY THIS AFTERNOON, CONFIDENCE HIGHEST AT
HUF AND BMG
- ADDITIONAL SHOWERS TONIGHT
- WIND SHIFTS THROUGH THE PERIOD
DISCUSSION:
MVFR TO BRIEFLY IFR CIGS WILL CONTINUE THROUGH THE OVERNIGHT HOURS
AHEAD OF THE NEXT ROUND OF RAIN DURING THE AFTERNOON HOURS TODAY.
CONFIDENCE IS HIGHEST IN THE 17Z TO 00Z TIMEFRAME TOWARDS BMG AND
HUF WHERE BOTH BRIEF GUSTY WINDS AND LIGHTNING ARE POSSIBLE.
ELSEWHERE AND THROUGHOUT THE REMAINDER OF THE TAF PERIOD, LIGHTNING
POTENTIAL LOOKS LOW. VSBYS SHOULD REMAIN VFR OUTSIDE OF STRONGER
SHOWERS AND STORMS. WINDS WILL VARY THROUGH THE PERIOD,
NORTHEASTERLY TONIGHT, SOUTHERLY TOMORROW AFTERNOON, AND WESTERLY
DURING THE EVENING. OUTSIDE OF CONVECTION, WESTERLY WINDS WILL
OCCASIONALLY GUST UP TO 20KT TOMORROW EVENING.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
AVIATION...WHITE
DISCUSSION...WHITE
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