017
FXUS63 KIND 151641
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1241 PM EDT MON JUN 15 2026
KEY MESSAGES
- COOLER TEMPERATURES THROUGH TUESDAY NIGHT WITH HIGHS IN THE LOW-
MID 70S AND LOWS IN THE 50S
- SHOWERS AND THUNDERSTORMS POSSIBLE TUESDAY, MARGINAL RISK OF
SEVERE WEATHER
- SHOWERS AND THUNDERSTORMS LIKELY ON WEDNESDAY WITH A MUCH
GREATER RISK OF SEVERE WEATHER
FORECAST UPDATE
ISSUED AT 904 AM EDT MON JUN 15 2026
SURFACE ANALYSIS LATE THIS MORNING SHOWS A SURFACE RIDGE OF HIGH
PRESSURE STRETCHING ACROSS THE CENTRAL PLAINS INTO INDIANA AND OHIO.
LIGHT WINDS AND PLEASANT DEW POINTS IN THE 50S WERE PRESENT. GOES19
SHOWS SOME HIGH CLOUDS PUSHING INTO EASTERN PARTS OF INDIANA, BUT
OVERALL SKIES WERE MOSTLY SUNNY. ALOFT, WATER VAPOR SHOWED A DEEP
AND BROAD AREA OF LOW PRESSURE OVER HUDSON BAY. THIS FEATURE WAS
PROVIDING CYCLONIC FLOW ACROSS MOST OF CANADA, THE GREAT LAKES AND
INDIANA. FURTHERMORE, THIS STRONG FLOW WAS KEEPING INTRUSIONS OF HOT
AND HUMID TROPICAL AIR OUT OF THE OHIO VALLEY.
THE SURFACE RIDGE IS EXPECTED TO REMAIN ACROSS CENTRAL INDIANA THIS
AFTERNOON. ACARS SOUNDINGS THIS MORNING SHOW A DRY COLUMN. WATER
VAPOR SHOWS SUBSIDENCE UPSTREAM OF INDIANA. CONVECTIVE TEMPERATURES
WILL NOT BE REACHED. THUS WILL CONTINUE WITH A MOSTLY SUNNY
AFTERNOON AND PLEASANT HIGH TEMPERATURES IN THE MIDDLE TO UPPER 70S.
DISCUSSION (TODAY THROUGH SUNDAY)
ISSUED AT 303 AM EDT MON JUN 15 2026
BROAD TROUGHING REMAINS OVER THE NORTHERN CONUS THIS WEEK WITH
MULTIPLE WAVES EMBEDDED WITHIN A QUASI-ZONAL JET STREAM THAT ROUNDS
ITS BASE. THE FIRST WAVE MAY BRING SCATTERED SHOWERS AND
THUNDERSTORMS ON TUESDAY. ON WEDNESDAY, ANOTHER POTENT WAVE ARRIVES
WITH THE POTENTIAL FOR THUNDERSTORMS AND SEVERE WEATHER. BROAD
TROUGHING PERSISTS THROUGH THE WEEK AND INTO THE WEEKEND.
TEMPERATURES THIS WEEK ARE EXPECTED TO REMAIN NEAR TO BELOW NORMAL
DUE TO THE PERSISTENT TROUGHING.
TUESDAY SEVERE WEATHER POTENTIAL
AS MENTIONED ABOVE, EMBEDDED WAVES ARE ROUNDING THE BASE OF THE
TROUGH AND ONE OF THESE IS EXPECTED TO ARRIVE ON TUESDAY AFTERNOON.
THE WAVE HELPS INDUCE CYCLOGENESIS TO OUR NORTH OVER WISCONSIN,
WHICH SHOULD ALLOW WINDS TO BECOME SOUTHERLY IN RESPONSE. GIVEN HOW
RECENTLY WE HAD AN AIR MASS CHANGE (YESTERDAY), IT APPEARS THAT RICH
MOISTURE MAY NOT HAVE ENOUGH TIME TO RETURN NORTHWARD. WINDS DON'T
BECOME SOUTHERLY UNTIL TONIGHT. HOWEVER, THIS MAY BE OFFSET BY
STEEP TO VERY STEEP LAPSE RATES AND SUFFICIENT SYNOPTIC-SCALE
FORCING. MODEL SOUNDINGS SHOW MODEST INSTABILITY BETWEEN 500-1500
J/KG MLCAPE, LAPSE RATES BETWEEN 6-8 C/KM. MODEL HODOGRAPHS ARE LONG
AND MOSTLY STRAIGHT, THOUGH SOME CURVATURE EXISTS IN THE LOWEST 3KM.
A COLD FRONT EXTENDING SOUTHWARD FROM THE LOW SHOULD ACT AS A
TRIGGER FOR CONVECTION. WIND SHEAR VECTORS ARE OFF PARALLEL, SO A
DISCRETE TO SEMI-DISCRETE STORM MODE IS EXPECTED. WITH STEEP LAPSE
RATES AND AMPLE SHEAR, SUPERCELLS ARE POSSIBLE, ESPECIALLY FURTHER
NORTHWEST CLOSER TO THE LOW ITSELF. MOST STORMS SHOULD NOT GROW INTO
SUPERCELLS, BUT MULTICELL CLUSTERS. STORMS SHOULD WEAKEN WITH
EASTWARD EXTENT AS INSTABILITY DIMINISHES.
IN TERMS OF HAZARDS, ALL HAZARDS ARE POSSIBLE IN SUPERCELLS. WITHIN
THE MULTICELL CLUSTERS, STRONG WINDS AND LARGE HAIL WILL BE THE
PRIMARY HAZARDS. OVERALL, THE THREAT APPEARS ON THE LOW END AS STORM
COVERAGE IS THE BIGGEST QUESTION. THE BEST LARGE-SCALE FORCING LOOKS
TO BE JUST TO OUR NORTH, WHICH MAY FOCUS THE SEVERE THREAT ACROSS
NORTHERN ILLINOIS AND INDIANA COMPARED TO CENTRAL INDIANA.
WEDNESDAY SEVERE WEATHER POTENTIAL
REGARDING WEDNESDAY'S SEVERE WEATHER POTENTIAL, GLOBAL MODELS SHOW A
LOW AMPLITUDE SHORTWAVE ROUNDING THE BASE OF THE BROADER TROUGH ON
WEDNESDAY. THIS ALSO ENABLES CYCLOGENESIS OVER THE UPPER MIDWEST,
WITH THE RESULTING SURFACE LOW TRACKING EAST INTO THE GREAT LAKES. A
POTENT LOW-LEVEL JET THEN DEVELOPS IN RESPONSE TO THE DEEPENING LOW,
ALLOWING FOR STRONG WARM AIR AND MOISTURE ADVECTION NORTHWARD.
ADDITIONALLY, THE UPPER-LEVEL JET STREAM REMAINS OVERHEAD. MODEL
HODOGRAPHS ARE LONG AND CURVED, WITH A SOUTHEASTERLY MEAN SHEAR
VECTOR.
A FEW SCENARIOS EXIST REGARDING CONVECTIVE EVOLUTION. FIRST, THE
STRONG WARM MOIST ADVECTION MAY BE SUFFICIENT TO INITIATE CONVECTION
TUESDAY NIGHT FAR UPSTREAM OVER IOWA. THIS COULD CONSOLIDATE INTO AN
MCS AND PROPAGATE SOUTHEASTWARD INTO THE STRONG LOW-LEVEL JET AND
WARM MOIST ADVECTION, AIDED BY SOUTHEASTERLY SHEAR. DAMAGING WINDS
AND LOCALIZED FLOODING WOULD BE THE PRIMARY HAZARDS IN SUCH A
SCENARIO.
SECOND, THERE IS NO EARLY CONVECTION AND OR THE ATMOSPHERE RECOVERS
FROM EARLIER STORMS (STRONG LOW-LEVEL JET MAY EASILY ALLOW THIS TO
HAPPEN EVEN IF THERE IS MORNING CONVECTION, SIMPLY BY ADVECTING THE
RAIN COOLED AIR MASS NORTHWARD). ATMOSPHERIC INSTABILITY IS
MAXIMIZED BY CONTINUED STRONG WARM MOIST ADVECTION AND SOLAR
INSOLATION. THUNDERSTORMS INITIATE ALONG THE SURFACE COLD FRONT OVER
ILLINOIS AND PROPAGATE SOUTHEASTWARD. SHEAR VECTORS PERPENDICULAR TO
THE ADVANCING FRONT MAY ALLOW FOR DISCRETE MODE INITIALLY, WITH
POTENTIAL FOR SUPERCELLS. ALL HAZARDS ARE POSSIBLE IN THIS
CIRCUMSTANCE. EVENTUALLY, CONVECTION WOULD GROW UPSCALE BECOMING
PRIMARILY A WIND THREAT.
THERE ARE A LOT OF MOVING PARTS WITH THIS, AND PREDICTABILITY IS
CURRENTLY LOW TO MEDIUM. GUIDANCE STILL NEEDS TO PROPERLY RESOLVE
THE INITIATING WAVE AND SURFACE LOW. ADDITIONALLY, THE POTENTIAL FOR
EARLY CONVECTION IS ALWAYS A WILD CARD AND CAN SUBSTANTIALLY ALTER
THE PRE-STORM ENVIRONMENT. GIVEN THE POTENTIAL FOR A STRONG LOW,
POTENT LOW-LEVEL JET AND SHEAR, SEVERE WEATHER APPEARS PROBABLE.
STAY TUNED FOR UPDATES AS GUIDANCE COMES INTO BETTER AGREEMENT AND
ADDITIONAL DETAILS CAN BE DISCERNED.
AVIATION (18Z TAF ISSUANCE)
ISSUED AT 1240 PM EDT MON JUN 15 2026
IMPACTS:
- VFR THIS TAF PERIOD
- CHANCE OF THUNDERSTORMS TUESDAY AFTERNOON AFTER 17Z.
DISCUSSION:
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
A SURFACE RIDGE OF HIGH PRESSURE WAS OVER INDIANA, EXTENDING WEST
FROM THE CENTRAL PLAINS STATES. GOES19 SHOWS SCT-BKN CU ACROSS
CENTRAL INDIANA.
THE SURFACE HIGH WILL MAINTAIN CONTROL OF THE WEATHER THIS AFTERNOON
PROVIDING FAIR WEATHER. AS HEATING IS LOST THIS AFTERNOON, CU WILL
DISSIPATE LEADING TO UNLIMITED CEILINGS OVERNIGHT.
ON TUESDAY, A QUICK MOVING UPPER LEVEL WEATHER DISTURBANCE WILL PUSH
TOWARD INDIANA. HRRR SUGGESTS A LINE OF SHOWER AND STORM DEVELOPMENT
PUSHING ACROSS THE TAF SITES WITHIN THE 16Z-22Z TIME FRAME. FOR NOW,
HAVE INCLUDED A TEMPO GROUP TO ACCOUNT FOR THAT. BRIEF MVFR
CONDITIONS ARE POSSIBLE WITH ANY TSRA THAT STRIKES A TAF SITE.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...PUMA
AVIATION...PUMA
DISCUSSION...ECKHOFF
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