097
FXUS63 KIND 142148
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
548 PM EDT THU AUG 14 2025
KEY MESSAGES
- SLIGHTLY COOLER-DRIER AIR THROUGH TONIGHT, MAINLY OVER THE
NORTHERN HALF OF CENTRAL INDIANA. LOWS TONIGHT IN THE 60S.
- HOT AND HUMID FRIDAY THROUGH EARLY NEXT WEEK. HEAT INDEX VALUES
NEAR OR EXCEED 100 AT TIMES LIKELY SATURDAY THROUGH MONDAY.
- GREATER THREAT FOR THUNDERSTORMS TO DEVELOP TUESDAY AND WEDNESDAY
AHEAD OF A COLD FRONT WITH COOLER AND DRIER AIR EXPECTED BY MID WEEK.
SHORT TERM (THIS EVENING THROUGH FRIDAY)
ISSUED AT 255 PM EDT THU AUG 14 2025
ANALYSIS SHOWS SURFACE HIGH PRESSURE TO OUR NORTH WITH SURFACE
RIDGING EXTENDING SOUTHWEST TO ABOUT MISSOURI. A LIGHT NORTH TO
NORTHEASTERLY WIND HAS THUS TAKEN HOLD WITH DRIER CONTINENTAL AIR
SLOWLY FILTERING INTO CENTRAL INDIANA. DEW POINTS HAVE DROPPED INTO
THE 60S WITH A FEW POCKETS OF UPPER 50S SHOWING UP. EFFICIENT
BOUNDARY LAYER MIXING WILL CONTRIBUTE TO LOWER DEW POINTS ESPECIALLY
FURTHER NORTH. ACROSS OUR SOUTH, FURTHER FROM THE DRIER AIR MASS,
DEW POINT READINGS IN THE LOW 70S REMAIN.
GOING FORWARD, GUIDANCE SHOWS SURFACE HIGH PRESSURE SLIDING EASTWARD
WITH MID TO UPPER-LEVEL RIDGING DEVELOPING OVER THE PLAINS. A
GRADUAL WARM UP IS ANTICIPATED AS THE RIDGE BUILDS EASTWARD INTO
THIS WEEKEND. TODAY'S HIGHS LOOK TO BE IN THE UPPER 80S TO NEAR 90.
WITH A RELATIVELY DRY AIR MASS IN PLACE, TONIGHT'S LOWS SHOULD DROP
NICELY AFTER SUNSET INTO THE MID TO UPPER 60S. SOME PATCHY GROUND
FOG IS POSSIBLE, BUT LOWER COVERAGE IS ANTICIPATED COMPARED TO
PREVIOUS DAYS BECAUSE OF THE DRIER AIR.
FRIDAY WILL SEE SURFACE WINDS BECOME MORE SOUTHERLY, ALLOWING HUMID
AIR TO RETURN NORTHWARD. DEW POINTS IN THE 70S ARE ONCE AGAIN
EXPECTED, WITH AMBIENT AIR TEMPERATURES LIKEWISE RISING TO NEAR 90
FOR MOST LOCATIONS. CLOUD COVER SHOULD BE LIMITED TO DIURNAL CUMULUS
AND SOME THIN CIRRUS AT TIMES.
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH FRIDAY. HOWEVER, A
LIGHT SHOWER IS POSSIBLE THIS AFTERNOON ACROSS THE SOUTHERN PORTIONS
OF THE AREA. ON FRIDAY, AN ISOLATED POP-UP SHOWER ALSO CANNOT BE
RULED OUT. THE PROBABILITY OF OCCURRENCE IS QUITE LOW, AROUND 10
PERCENT, SO MENTIONABLE POPS WILL NOT BE CARRIED IN THE FORECAST FOR
NOW.
LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 255 PM EDT THU AUG 14 2025
HOT AND HUMID CONDITIONS PERSIST INTO NEXT WEEK FOR ALL OF CENTRAL
INDIANA AS RIDGING ALOFT REMAINS THE DOMINANT WEATHER INFLUENCE OVER
THE AREA. WHILE CONFIDENCE IS HIGH IN HOT TEMPERATURES AND HIGH
HUMIDITY, LOWER CONFIDENCE EXISTS IN THE LONG TERM REGARDING DAILY
STORM CHANCES. WHILE SOME PORTIONS OF THE ARE MAY NOT SEE RAIN UNTIL
MID NEXT WEEK, OTHER AREAS COULD SEE STORMS AS EARLY AS SATURDAY.
UNCERTAINTY FURTHER INCREASES BEYOND EARLY NEXT WEEK WITH THE
POTENTIAL FOR A DEVELOPING BLOCKY PATTERN ALOFT AS ERIN MOVES
TOWARDS THE WESTERN ATLANTIC BASIN AS A HURRICANE. CONFIDENCE
CONTINUES TO GROW HOWEVER IN A MORE SUBSTANTIAL PATTERN CHANGE
LOCALLY BY WEDNESDAY AS THE RIDGE RETROGRADES INTO THE INTERMOUNTAIN
WEST, ALLOWING A COLD FRONT TO SURGE SOUTH BRINGING AN END TO THE
EXCESSIVE HEAT.
THIS WEEKEND...
LATEST MEDIUM RANGE GUIDANCE HAS THE UPPER RIDGE CENTERED OVER
MISSOURI AND ILLINOIS THIS WEEKEND WHILE THE SURFACE HIGH MEANDERED
AROUND THE OHIO VALLEY. THE MAIN STORY THIS WEEKEND WILL BE THE WELL
ABOVE NORMAL TEMPERATURES AS RIDGING KEEPS THE HOT AIRMASS PARKED
OVER THE REGION. HIGH CONFIDENCE IN HIGHS REACHING THE 90 DEGREE
MARK EACH DAY WITH HIGH HUMIDITY AND HEAT INDICES IN THE 100-105
DEGREE RANGE.
THE MAIN UNCERTAINTY BOTH SATURDAY AND SUNDAY INVOLVES THE
POSSIBILITY OF UPSTREAM MESOSCALE CONVECTIVE SYSTEMS RIDING OVER THE
RIDGE AND INTO THE NORTHERN HALF OF INDIANA. THERE HAS BEEN RUN TO
RUN CONSISTENCY AMONG SOME MODELS, INCLUDING THE ECMWF AI,
INDICATING THIS POSSIBILITY. WHILE IT IS STILL TOO FAR OUT TO
DETERMINE SMALLER MESOSCALE DETAILS OF THIS SET UP, CHANCES FOR
STORMS ARE INCREASING ALONG AND NORTH OF I-70. THESE THUNDERSTORM
COMPLEXES WILL LIKELY BE WEAKENING AS THEY ENTER INDIANA AS THE
BETTER DYNAMICS, MOISTURE, AND FORCING FOR ASCENT WILL BE FURTHER
NORTH AND WEST. CONFIDENCE IS STILL LOW ENOUGH TO OMIT POPS FROM THE
FORECAST AT THE MOMENT, BUT IF RUN TO RUN CONSISTENCY CONTINUES,
STORM CHANCES WILL NEED TO BE ADDED FOR AT LEAST NORTH CENTRAL
INDIANA FOR SATURDAY AND SUNDAY.
NEXT WEEK...
A SIMILAR PATTERN CONTINUES INTO MONDAY AS RIDGING SLOWLY PUSHES
EASTWARD AHEAD OF AN APPROACHING UPPER TROUGH FROM THE NORTHWEST.
WINDS THROUGH THE COLUMN BECOME SOUTHWESTERLY AS THE LOW LEVEL JET
ON THE WEST SIDE OF THE LOW LEVEL RIDGE NUDGES CLOSER TO THE AREA.
WHILE ANY STORM CHANCES LOCALLY LIKELY REMAIN IN NORTHERN INDIANA ON
MONDAY, CHANCES FOR STORMS INCREASE ACROSS CENTRAL INDIANA AS UPPER
TROUGHING AND AN ASSOCIATED COLD FRONT MOVE INTO THE AREA TUESDAY
AND WEDNESDAY. CONFIDENCE REMAINS LOW IN THE EXACT EVOLUTION OF
STORMS AND MESOSCALE FEATURES EARLY TO MID NEXT WEEK AS EACH DAY'S
CONVECTIVE SET UP WILL BE HEAVILY INFLUENCED BY WHAT OCCURS
UPSTREAM. DESPITE LOWER CONFIDENCE IN THE EXACT DETAILS, THERE IS
HIGHER CONFIDENCE IN BETTER STORMS CHANCES FOR CENTRAL INDIANA BOTH
TUESDAY AND WEDNESDAY WITH HEAVY RAIN, LIGHTNING, AND GUSTY WINDS
BEING POTENTIAL THREATS. OUTSIDE OF STORMS, ABOVE AVERAGE HIGHS IN
THE 90S AND HEAT INDICES OVER 100 SHOULD CONTINUE INTO AT LEAST
TUESDAY.
LONGER RANGE GUIDANCE CONTINUES TO INDICATE A SLIGHT COOL DOWN BY
THE LATTER HALF OF NEXT WEEK AS TROUGHING MOVES IN OVERHEAD AND
POSSIBLY STALLS WITHIN THE OHIO VALLEY AS ERIN NEARS IN THE WESTERN
ATLANTIC. A MORE SUBSTANTIAL COOL DOWN IS LOOKING INCREASINGLY
POSSIBLE IN THE 8-14 DAY TIMEFRAME AND MUCH STRONGER TROUGHING
BRINGS WIDESPREAD BELOW NORMAL TEMPERATURE ANOMALIES TO THE GREAT
LAKES REGION AND NORTHEAST.
AVIATION (00Z TAF ISSUANCE)
ISSUED AT 548 PM EDT THU AUG 14 2025
IMPACTS:
- VFR CONDITIONS ARE EXPECTED THIS TAF PERIOD.
DISCUSSION:
BROAD HIGH PRESSURE CENTERED OVER ONTARIO AND QUEBEC CONTINUE TO
INFLUENCE THE WEATHER ACROSS THE GREAT LAKES AND INTO THE OHIO
VALLEY.
SCT DIURNAL CU ACROSS CENTRAL INDIANA IS EXPECTED TO DIMINISH ACROSS
THE TAF SITES THIS EVENING AS DIURNAL HEATING IS LOST.
LITTLE CHANGE IN AIR MASS ACROSS THE AREA ALONG WITH DEW POINT
DEPRESSIONS LESS THAN 1-2F SUGGESTS PATCHY MVFR FOG WILL BE POSSIBLE
ONCE AGAIN, MAINLY AT HUF/BMG AND LAF.
ANY MORNING FOG WILL QUICKLY BURN OFF AS HEATING RESUMES. LOWER
LEVEL FLOW IS EXPECTED TO BECOME A MORE SOUTHERLY DIRECTION ON
FRIDAY AND SOME VFR CU DEVELOPMENT WILL BE POSSIBLE.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...ECKHOFF
LONG TERM...CM
AVIATION...PUMA
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