884
FXUS63 KIND 211820
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
220 PM EDT MON SEP 21 2026
KEY MESSAGES
- MAINLY CLOUDY AND COOL THROUGH MIDWEEK
- DRY AND SEASONABLE LATE WEEK INTO THE WEEKEND WITH GRADUALLY
WARMING TEMPERATURES
DISCUSSION (THIS EVENING THROUGH MONDAY)
ISSUED AT 220 PM EDT MON SEP 21 2026
MUCH COOLER AIR HAS OVERSPREAD THE REGION IN THE WAKE OF THE
FRONTAL PASSAGE LATE SUNDAY. CLOUDY AND BREEZY CONDITIONS ARE
EXPECTED THROUGH WEDNESDAY AS AN UPPER LOW MOVES SLOWLY THROUGH THE
AREA. THIS FEATURE WILL CUTOFF OVER THE MID ATLANTIC BY LATE
WEEK...WITH MUCH DRIER AIR BEING PULLED SOUTH INTO THE OHIO VALLEY
THROUGH THE WEEKEND.
REST OF TODAY THROUGH WEDNESDAY NIGHT
IN THE WAKE OF THE MORNING RAIN...A DAMP AND DREARY AIRMASS REMAINS
ACROSS CENTRAL INDIANA UNDER A THICK STRATUS DECK AND WITH BREEZY
NORTHEAST WINDS. 18Z TEMPERATURES WERE MUCH COOLER THAN WHAT HAS
BEEN EXPERIENCED OVER THE LAST SEVERAL DAYS WITH MUCH OF CENTRAL
INDIANA IN THE 60S.
THERE REMAIN A FEW LIGHT SHOWERS OR SPRINKLES OVER THE SOUTHEAST
HALF OF THE FORECAST AREA BUT THE OVERALL TREND SINCE THE MORNING
HAS BEEN FOR RAINFALL COVERAGE TO DECREASE EXTENSIVELY AS THE
FRONTAL BOUNDARY THAT MOVED THROUGH THE AREA SUNDAY AFTERNOON AND
EVENING HAS NOW MOVED WELL SOUTH INTO THE TENNESSEE VALLEY.A FEW
LIGHT SHOWERS REMAIN POSSIBLE FOR THE NEXT FEW HOURS BEFORE
DEPARTING. ABUNDANT MOISTURE PERSISTS THROUGH THE BOUNDARY LAYER
TRAPPED BENEATH A STOUT INVERSION. MODEL SOUNDINGS SHOW THE
INVERSION WEAKENING SLIGHTLY THIS EVENING WHICH MAY BE JUST ENOUGH
TO ALLOW FOR A BRIEF PERIOD WITH BREAKS IN THE STRATUS DECK. AS THE
INVERSION STRENGTHENS OVERNIGHT HOWEVER...EXPECT THE STRATUS DECK TO
THICKEN BACK UP WITH CEILINGS LOWERING AGAIN INTO TUESDAY MORNING.
CANNOT ENTIRELY RULE OUT A FEW SPRINKLES TONIGHT BUT LOW CONFIDENCE
IN THIS OCCURRING.
CLOUDS WILL REMAIN ON TUESDAY AS AN UPPER LOW PIVOTS INTO THE REGION
FROM THE NORTHWEST. THE UPPER LOW WILL BRING ISOLATED LIGHT SHOWERS
ACROSS THE FAR NORTHEAST PORTION OF THE FORECAST AREA OTHERWISE
EXPECT A CONTINUATION OF WEATHER TODAY WITH THICK STRATUS AND COOL
N/NE FLOW. THE UPPER LOW WILL BE SLOW TO SHIFT EAST OF THE AREA AS
IT BECOMES CUTOFF FROM THE MEAN FLOW ALOFT WELL TO THE NORTH OF THE
REGION. THIS WILL KEEP AN ABUNDANCE OF CLOUDS OVER MOST OF THE
FORECAST AREA THROUGH WEDNESDAY AS WELL WITH AGAIN A LOW CHANCE FOR
A FEW SHOWERS ACROSS OUR NORTHEAST COUNTIES. MORE SUBSTANTIAL BREAKS
IN THE CLOUDS SHOULD COME WEDNESDAY NIGHT AS RIDGING ALOFT SLOWLY
SPREADS INTO THE OHIO VALLEY FROM THE WEST.
TEMPS...HIGHS WILL NOT GET OUT OF THE 60S THIS AFTERNOON FOR MUCH OF
THE FORECAST AREA...THE COOLEST DAY SINCE MAY 23. EXPECT SIMILAR
TEMPERATURES BOTH TUESDAY AND WEDNESDAY WITH HIGHS RANGING FROM THE
MID 60S NORTHEAST TO THE LOWER 70S SOUTHWEST. LOWS WILL BE IN THE
50S.
THURSDAY THROUGH SUNDAY
THE AFOREMENTIONED UPPER LOW WILL SETTLE OVER THE MID ATLANTIC
REGION DURING THE SECOND HALF OF THE WEEK. COOL E/NE FLOW AND AT
LEAST SOME LINGERING CLOUD COVER ON THE BACK SIDE OF THE DEVELOPING
CUTOFF LOW WILL MAINTAIN BELOW NORMAL TEMPERATURES THURSDAY WITH
HIGHS RANGING FROM THE UPPER 60S TO THE MID 70S FROM NORTHEAST TO
SOUTHWEST. RIDGING ALOFT WILL GRADUALLY SHIFT INTO THE OHIO VALLEY
WITH AN AXIS OF DEEPENING SUBSIDENCE ADVECTING INTO THE REGION FROM
THE NORTH. UNDER MAINLY CLEAR SKIES...TEMPERATURES WILL RECOVER BACK
TO LATE SEPTEMBER NORMALS WITH HIGHS WARMING INTO THE MID AND UPPER
70S BY SUNDAY AND PERHAPS INTO THE LOWER 80S OVER PARTS OF THE
FORECAST AREA BY MONDAY. THE COOLEST NIGHT SINCE THE SPRING COMES
FRIDAY NIGHT AS LOWS IN THE MID AND UPPER 40S WILL BE COMMON...WITH
TEMPERATURES RECOVERING INTO THE 50S FOR LOWS BY THE END OF THE
WEEKEND.
AVIATION (18Z TAF ISSUANCE)
ISSUED AT 1233 PM EDT MON SEP 21 2026
IMPACTS:
- PREDOMINANT MVFR CEILINGS EXPECTED THROUGH MUCH OF THE PERIOD. IFR
AT TIMES EARLY THIS AFTERNOON AND AGAIN LATE TONIGHT PRIMARILY AT
KBMG
- GUSTS NEAR 20KT POSSIBLE THROUGH THE AFTERNOON, MAINLY AT KLAF
DISCUSSION:
SHOWERS HAVE LARGELY SHIFTED EAST OF CENTRAL INDIANA EARLY THIS
AFTERNOON BUT PLENTIFUL LOW LEVEL MOISTURE LINGERS AND IS TRAPPED
BENEATH AN INVERSION. THIS WILL ENSURE LOW STRATUS GOES NOWHERE OVER
MOST OF THE NEXT 24 HOURS. CEILINGS WILL RESIDE IN THE MVFR CATEGORY
THIS AFTERNOON BEFORE POTENTIALLY BRIEFLY BREAKING OUT TO LOW VFR
LEVELS FOR A FEW HOURS THIS EVENING. STRENGTHENING OF THE INVERSION
LATE TONIGHT WILL AID IN CEILINGS SLIPPING BACK TO BETWEEN 1000-
2000FT WITH THE POSSIBILITY OF IFR CEILINGS AT KBMG. LOW CEILINGS
WILL CONTINUE ON TUESDAY.
NORTHEAST WINDS WILL CONTINUE THROUGH THE FORECAST PERIOD. PERIODIC
GUSTS TO AROUND 20KTS ARE EXPECTED AT KLAF THIS AFTERNOON...
OTHERWISE WILL SEE A STEADY 10-15KT WIND AT ALL TERMINALS.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
AVIATION...RYAN
DISCUSSION...RYAN
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