803
FXUS63 KIND 200519
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
119 AM EDT WED MAY 20 2026
KEY MESSAGES
- THUNDERSTORMS POSSIBLE ACROSS SOUTHEN CENTRAL INDIANA. LOCALIZED
FLOODING IS POSSIBLE.
- A FLOOD WATCH IS IN EFFECT FROM 3PM TODAY TO 2PM WEDNESDAY.
- COOLER MID WEEK WITH A BRIEF BREAK FROM RAIN CHANCES, BEFORE
SHOWERS AND STORMS RETURN TO THE FORECAST LATE WEEK INTO THE
HOLIDAY WEEKEND
FORECAST UPDATE
ISSUED AT 919 PM EDT TUE MAY 19 2026
SURFACE ANALYSIS THIS EVENING SHOWS A COLD FRONT ACROSS CENTRAL
INDIANA, STRETCHING FROM NEAR FWA TO NORTH OF IND TO NEAR VINCENNES.
THE FRONT WAS SLOWLY SAGGING SOUTHWARD ACROSS CENTRAL INDIANA. RADAR
TRENDS CONTINUE TO SHOW SCATTERED CONVECTION ACROSS SOUTHERN
INDIANA, MAINLY IN A DECAYING STATE AS HEATING CONTINUES TO BE LOST.
ALOFT, WATER VAPOR SHOWS A PLUME OF MOISTURE STREAMING FROM EASTERN
TX INTO THE OHIO VALLEY WHILE WARM SW FLOW WAS IN PLACE ALOFT. GOES19
SHOWS MAINLY CONVECTIVE DEBRIS CLOUDS WITHIN THAT FLOW STREAMING
ACROSS IL AND IN.
OVERNIGHT, THE FRONT IS EXPECTED TO CONTINUE TO SAG SOUTHWARD, AND
FLOW IN THE WAKE OF THE FRONT WILL BECOME NORTHEASTERLY AS STRONGER
HIGH PRESSURE BEGINS TO BUILD ACROSS INDIANA FROM THE NORTHERN
PLAINS. HOWEVER THE STEADY STREAM OF MOISTURE ALOFT FLOWING FROM THE
SOUTHWEST IN COMBINATION WITH THE LINGERING FRONT ACROSS SOUTHERN
INDIANA MAY RESULT IN OCCASIONAL SHOWERS AND STORMS ACROSS SOUTHERN
INDIANA OVERNIGHT. THUS WILL KEEP A DRY FORECAST IN THE NORTH AND NW
WHERE NE WINDS AND DRY AIR IS PREDOMINATE. POPS WILL REMAIN
OVERNIGHT ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA. DUE TO THE
EARLIER SUGGESTED FACTORS, HRRR SUGGESTS PERIODIC SHOWERS PUSHING
ACROSS SOUTHERN INDIANA THROUGH THE NIGHT. WILL CONTINUE TO WATCH
CLOSELY OVERNIGHT FOR HEAVY RAINS THAT COULD RESULT IN FLOODING.
ONGOING FLOOD WATCH WILL REMAIN.
DISCUSSION (THIS EVENING THROUGH TUESDAY)
ISSUED AT 300 PM EDT TUE MAY 19 2026
TODAY AND TONIGHT -
SATELLITE IMAGERY SHOWS CUMULUS DEVELOPING AS THE BOUNDARY LAYER
BECOMES DESTABILIZED (IND ACARS SHOWS AROUND 1500 J/KG MLCAPE). AS
SUCH, RENEWED CONVECTIVE ACTIVITY APPEARS LIKELY AGAIN THIS
AFTERNOON. IN FACT, A FEW SHOWERS HAVE ALREADY POPPED UP NEAR
COLUMBUS AS OF 2PM.
IN TERMS OF HAZARDS, RAP SOUNDINGS INDICATE THAT SOME MID-LEVEL DRY
AIR MAY BE PRESENT TODAY. ACARS SOUNDINGS FROM IND SHOW THE DRY AIR
AND DCAPE VALUES OF 1100 J/KG AS OF 2PM. THIS, COMBINED WITH STEEP
LAPSE RATES AND A LLJ AROUND 30-40KT, COULD ALLOW FOR DOWNBURST AND
EFFICIENT DOWNWARD MOMENTUM TRANSFER. ABOUT 25 KNOTS OF EFFECTIVE
SHEAR MAY ALSO BE ENOUGH TO ALLOW FOR LOOSE ORGANIZATION INTO
MULTICELL CLUSTERS. THEREFORE, STRONG TO DAMAGING WIND GUSTS ARE
POSSIBLE WITH STORMS TODAY.
THE WIND THREAT DIMINISHES AFTER SUNSET AS THE COLUMN MOISTENS AND
LAPSE RATES WEAKEN SLIGHTLY. RAP SOUNDINGS SHOW THE ATMOSPHERE
BECOMING MORE EFFICIENT FOR RAINFALL PRODUCTION OVERNIGHT (DEEP WARM
CLOUD LAYER, SATURATION TO THE EL, AND MOIST ADIABATIC LAPSE RATES).
A COLD FRONT SAGGING SOUTH ACROSS INDIANA WILL INTERACT WITH AN MCV
APPROACHING FROM THE SOUTHWEST, PROLONGING LARGE-SCALE LIFT TONIGHT.
MOST GUIDANCE IS ON BOARD WITH SHOWERS AND THUNDERSTORMS CONTINUING
ON AND OFF THROUGH THE NIGHT. THERE IS A SIGNAL FOR HEAVY RAIN
WITHIN MOST GUIDANCE WITH POCKETS OF 1 TO 3 INCHES ACROSS THE
SOUTHERN HALF OF OUR AREA. QPF COVERAGE IN GUIDANCE ISN'T AS
WIDESPREAD AS YESTERDAY, BUT THESE POCKETS TEND TO LINE UP WHERE THE
HEAVIEST RAIN FELL. ADDITIONAL FLOODING MAY BE POSSIBLE TONIGHT AND
A FLOOD WATCH HAS BEEN ISSUED FOR THE SOUTHERN HALF OF OUR CWA.
WEDNESDAY THROUGH MONDAY -
ONCE THE FRONT HAS PUSHED SOUTH OF THE AREA, IT WILL STALL OUT A
BIT, THOUGH HIGH PRESSURE PASSING THROUGH THE GREAT LAKES IN ITS
WAKE WILL KEEP IT SUPPRESSED TO THE SOUTH AND ALLOW FOR BOTH A BRIEF
COOLDOWN AND A BREAK IN PRECIP CHANCES FROM LATE WEDNESDAY INTO
THURSDAY EVENING.
RAIN CHANCES RETURN LATE WEEK INTO EARLY NEXT WEEK AS A LARGE UPPER
LEVEL LOW SWINGS THROUGH THE NORTHERN TIER OF THE COUNTRY AND PULLS
A WARMER AND MOIST AIRMASS BACK INTO THE AREA, THOUGH CHANCES WITH
THE EXCEPTION OF FRIDAY WILL BE LOW FOR THE TIME BEING GIVEN
SIGNIFICANT MODEL INCONSISTENCIES AND RESULTING UNCERTAINTY.
AVIATION (06Z TAF ISSUANCE)
ISSUED AT 119 AM EDT WED MAY 20 2026
IMPACTS:
- SHOWERS AND A FEW THUNDERSTORMS, PRIMARILY FROM HUF/IND
SOUTHEASTWARD
- CEILINGS LIKELY TO DETERIORATE TO MVFR, WITH IFR AT BMG
DISCUSSION:
A COLD FRONT HAS TEMPORARILY STALLED OVER THE AREA AND IS PRODUCING
ADDITIONAL SHOWERS AND A FEW THUNDERSTORMS ACROSS THE SOUTHEASTERN
HALF OF THE AREA TONIGHT. THIS WILL CONTINUE MUCH OF THE OVERNIGHT
AND ADDITIONAL SHOWERS WILL BE POSSIBLE DURING THE DAY ON WEDNESDAY.
TRAPPED LOW LEVEL MOISTURE ALONG AND NORTH OF THE BOUNDARY AS IT
SLOWLY PUSHES SOUTHWARD WILL CAUSE CEILINGS TO DETERIORATE
OVERNIGHT, FALLING TO MVFR AT LEAST BRIEFLY AT ALL SITES LATER THIS
MORNING. BMG WILL LIKELY DROP INTO IFR AT LEAST BRIEFLY, BUT MVFR
MAY PREDOMINATE AT ALL SITES EXCEPT LAF MUCH OF THE PERIOD.
WINDS WILL GENERALLY BE NORTH/NORTHWESTERLY EARLY, BUT GRADUALLY
BECOME NORTHERLY THEN NORTHEASTERLY WITH TIME.
IND WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH THIS AFTERNOON FOR INZ052>055-060>064-
067>072.
UPDATE...PUMA
AVIATION...NIELD
DISCUSSION...NIELD/ECKHOFF
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