788
FXUS63 KIND 151741
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
141 PM 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 25 AND 35
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 18Z AND 20Z, PROGRESSING
ACROSS THE INDIANAPOLIS METRO AREA BETWEEN 21Z AND 00Z, AND
EXITING EASTERN COUNTIES BY 02Z-04Z WITH THE POTENTIAL THAT THIS
OCCURS OVER 2 ROUNDS THROUGH THE DAY QPF WILL AVERAGE BETWEEN
0.50 AND 1.00 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 25-35 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 (18Z TAF ISSUANCE)
ISSUED AT 141 PM EDT THU OCT 15 2026
IMPACTS:
- MOSTLY MVFR CEILINGS ARE EXPECTED FOR ALL OF THIS TAF PERIOD.
- SHOWERS AND STORMS EXPECTED THIS AFTERNOON INTO THE EVENING.
- ADDITIONAL SHOWERS TONIGHT, COVERAGE DECREASING AFTER 15Z.
- WIND SHIFTS THROUGH THE PERIOD.
- WIND GUSTS 15-20KT TONIGHT, UP TO 27KT AFTER 15Z FRIDAY.
DISCUSSION:
IFR CEILINGS ARE WIDESPREAD ALONG AND SOUTH OF A SLOWLY ADVANCING
WARM ACROSS SOUTHERN PORTIONS OF CENTRAL INDIANA EARLY THIS
AFTERNOON. EXPECT IFR CONDITIONS AT KBMG TO IMPROVE TO MVFR AROUND
19Z OWING TO INCREASING VERTICAL MOTION WITH PRESENCE OF CONVECTIVE
SHOWERS IN THE AREA. ELSEWHERE MVFR CEILINGS ARE EXPECTED TO
CONTINUE THROUGH THE PERIOD, WITH A FEW BREAKS POSSIBLE AT KHUF THIS
AFTERNOON.
ATTENTION TURNS TO CONVECTION AND LIKELY IMPACTS TO TERMINALS THIS
LATE AFTERNOON/EARLY EVENING. FIRST ROUND OF TS CURRENTLY MOVING
TOWARDS KHUF WILL BE FAIRLY ISOLATED STAYING SOUTH OF KIND AND NORTH
OF KBMG. LARGER CONVECTIVE LINE OVER WESTERN IL WILL MOVE INTO THE
TERMINALS AFTER 20Z. FOR THIS ROUND, HAVE ADDED TEMPO WORDING FOR
TSRA AT ALL BUT KLAF, WITH WIND GUSTS TO 30KT AND IFR VIS IN TSRA.
THIS ACTIVITY SHOULD BE OVER BY 00Z AT ALL THE TERMINALS.
IN THE WAKE OF THIS MAIN CONVECTIVE LINE, WINDS WILL GRADUALLY SHIFT
TO W-SW WITH GUSTS TO 20 KTS EXPECTED OVERNIGHT. THE MAIN FRONT WILL
MOVE TOWARDS THE TERMINALS BETWEEN 06-12Z WITH WINDS BECOMING W-NW
WITH GUSTS OVER 20KT. A PERIOD OF STEADY SHOWERS IS EXPECTED ALONG
AND IN THE WAKE OF THE FRONT, WITH ACTIVITY EXPECTED TO DIMINISH TO
VCSH BY LATE MORNING. STRONGER WIND GUSTS WILL DEVELOP BY LATE
MORNING WITH GUSTS AS HIGH AS 27KTS BY MIDDAY FRIDAY.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
AVIATION...CROSBIE
DISCUSSION...WHITE
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