977
FXUS63 KIND 091338
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
938 AM EDT TUE SEP 9 2025
KEY MESSAGES
- GRADUALLY CLIMBING TEMPERATURES THROUGH THE WEEK WITH NEAR 90
DEGREE HIGHS BY SATURDAY
- DRY WEATHER OUTSIDE OF LOW RAIN CHANCES THIS WEEKEND MAY LEAD TO
CONTINUED EXPANSION OF DROUGHT CONDITIONS INTO NEXT WEEK
FORECAST UPDATE
ISSUED AT 938 AM EDT TUE SEP 9 2025
THE FORECAST REMAINS IN GOOD SHAPE WITH ONLY MINOR ADJUSTMENTS
NEEDED. SURFACE HIGH PRESSURE IS SHIFTING NORTHEASTWARD, BUT REMAINS
IN CONTROL ACROSS THE REGION. THIS WILL CONTINUE TO PROVIDE QUIET
WEATHER CONDITIONS. EFFICIENT DIURNAL HEATING AIDED BY A DRY AIRMASS
AND CLEAR SKIES HAS HELPED TEMPERATURES WARM QUICKLY AFTER A CHILLY
START TO THE DAY. HOURLY TEMPERATURES AND MAX TEMPERATURES WERE
ADJUSTED SLIGHTLY TO ACCOUNT FOR THIS. EXPECT HIGHS TO REACH THE
UPPER 70S TO LOW 80S LATER TODAY.
DEEP MIXING DURING THE AFTERNOON AND DRY AIR ALOFT WILL RESULT IN
LOW RH AROUND OR SLIGHTLY BELOW 30%. THIS ALONG WITH DRYING FUELS
MAY LEAD TO A SLIGHTLY ELEVATED FIRE RISK, BUT LIGHT WINDS WILL
LIMIT THE OVERALL THREAT. PLEASE REFER TO THE FIRE WEATHER
DISCUSSION BELOW FOR MORE DETAILS ON THE FIRE WEATHER THREAT THROUGH
THE FORESEEABLE FUTURE.
SHORT TERM (TODAY AND TONIGHT)
ISSUED AT 255 AM EDT TUE SEP 9 2025
SURFACE HIGH PRESSURE REMAINS NEAR THE REGION PROVIDING CONTINUED
QUIET WEATHER CONDITIONS. THE CENTER OF THE SURFACE HIGH PRESSURE
WILL BE OVER NEW ENGLAND TODAY, SHIFTING NORTHEAST THROUGHOUT THE
SHORT TERM PERIOD. THIS WILL ALLOW FOR WINDS TO BECOME MORE
SOUTHEASTERLY AND THUS BEGIN THE TREND OF WARMING TEMPERATURES
EXPECTED LATER IN THE WEEK. THE LIGHT SOUTHEASTERLY FLOW AND
PLENTIFUL SUNSHINE SHOULD WARM TEMPERATURES WELL INTO THE UPPER 70S
TODAY WITH SOME LOCATIONS POTENTIALLY REACHING OR EXCEEDING THE 80F
MARK.
FORECAST SOUNDINGS SHOW DEEP MIXING INTO A DRY AIRMASS ALOFT WHICH
WILL RESULT IN LOW RH VALUES DURING THE AFTERNOON. FIRE CONCERNS
REMAIN LOW DUE TO LIGHT WINDS. A SUBTLE UPPER WAVE IS EXPECTED TO
APPROACH CENTRAL INDIANA LATE IN THE DAY AND INTO TONIGHT. WHILE THE
AIRMASS WILL BE MUCH TOO DRY FOR PRECIPITATION, SOME INCREASE IN MID-
HIGH CLOUDS CAN BE EXPECTED AS WELL AS DEW POINTS INCREASING BY A
FEW DEGREES. MODEL SOUNDINGS ALSO SHOW THE COLUMN BECOMING LESS DRY
AS THE WAVE APPROACHES.
EXPECT TEMPERATURES TO QUICKLY FALL AFTER SUNSET DUE TO A DECENTLY
FAVORABLE SETUP FOR RADIATIONAL COOLING, ALTHOUGH NOT QUITE AS
EFFICIENT AS THE PREVIOUS FEW NIGHTS. LOOK FOR LOWS GENERALLY IN THE
LOW 50S TONIGHT.
LONG TERM (WEDNESDAY THROUGH MONDAY)
ISSUED AT 255 AM EDT TUE SEP 9 2025
WEDNESDAY THROUGH FRIDAY.
THE GRADUAL WARMING TREND WILL CONTINUE INTO WEDNESDAY WITH BROAD
HIGH PRESSURE ACROSS THE OHIO VALLEY PERSISTING AND WEAK TO NO FLOW
NEAR THE SURFACE AND ALOFT. MODEL SOUNDINGS SHOW NEAR SATURATION AT
THE TOP OF THE BOUNDARY LAYER WEDNESDAY AFTERNOON WHICH SHOULD ALLOW
FOR A SPARSE DIURNAL CU FIELD. WEAK FLOW AT THE TOP OF THE BOUNDARY
LAYER WILL LIMIT THE MIXING OUT OF SURFACE MOISTURE BUT LIKE
PREVIOUS DAYS, EXPECT MIN RH VALUES TO DROP INTO THE 25 TO 35
PERCENT RANGE. AFTERNOON HIGHS SHOULD TOP OUT IN THE LOW TO MID 80S
WEDNESDAY. NEAR IDENTICAL CONDITIONS ERE EXPECTED FOR THURSDAY WITH
SLIGHTLY LOWER RH VALUES FRIDAY DUE TO THE WARMER HIGHS WHICH MAY
APPROACH 90 DEGREES IN THE WEST. CONCERNS CONTINUE FOR SLIGHTLY
ELEVATED FIRE WEATHER DANGER WITH DETAILS COVERED IN THE FIRE
SECTION AT THE BOTTOM.
SATURDAY THROUGH MONDAY.
FORECAST CONFIDENCE IS LOW THIS WEEKEND INTO NEXT WEEK WITH A WIDE
MODEL SPREAD ON THE SYNOPTIC PATTERN. THE BROADER PATTERN HAS A
BUILDING RIDGE ACROSS THE CENTRAL US WITH THE POTENTIAL FOR RIDGE-
RIDING COMPLEXES OF STORMS FOR THE WEEKEND, BUT EXACT DETAILS REMAIN
HIGHLY UNCERTAIN. WHILE THERE WILL BE SOME MOISTURE RETURN INTO THE
OHIO VALLEY BY SATURDAY, INSTABILITY VALUES WILL BE FAIRLY MEAGER,
BUT A STRENGTHENING JET ACROSS THE UPPER MIDWEST WILL INCREASE SHEAR
AND CREATE A FAVORABLE ENVIRONMENT FOR THUNDERSTORM ORGANIZATION. AT
THIS POINT, CONFIDENCE IS FAIRLY HIGH IN AT LEAST SOME THUNDERSTORMS
ACROSS THE GREAT LAKES REGION, BUT CONFIDENCE IS LOW THAT ANY REACH
AS FAR SOUTH AS CENTRAL INDIANA.
FORECAST CONFIDENCE CONTINUES TO DECREASE SUNDAY INTO MONDAY WITH A
WIDE RANGE OF MODEL SOLUTIONS IN HOW THEY HANDLE BOTH THE ONGOING
RIDGE AND A DEEPENING UPPER LEVEL LOW ACROSS SOUTHERN CANADA.
CURRENTLY LEANING TOWARDS A MORE PERSISTENT PATTERN WITH THE UPPER
LEVEL RIDGE HELPING TO PUSH THE AFOREMENTIONED LOW PRESSURE FURTHER
EAST INTO THE NORTHEASTERN STATES, BUT WILL HAVE TO CONTINUE TO
MONITOR FORECAST TRENDS. WITH ENSEMBLE OUTPUT KEEPING CHANCES OF QPF
GREATER THAN 0.01" AT LESS THAN 30 PERCENT OVER THE NEXT 7 DAYS,
EXPECT TO SEE FURTHER EXPANSION IN DROUGHT CONDITIONS AND
EXACERBATING FIRE WEATHER CONCERNS GOING INTO THE SECOND HALF OF THE
MONTH.
AVIATION (12Z TAF ISSUANCE)
ISSUED AT 651 AM EDT TUE SEP 9 2025
IMPACTS:
- NONE
DISCUSSION:
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
SOME CIRRUS WILL PASS THROUGH AT TIMES, AND PERHAPS A FEW CUMULUS
MAY POP THIS AFTERNOON. WINDS WILL INCREASE SOME AND SHIFT AS THE
DAY GOES ON TO BE SOUTHEASTERLY AT 10 KTS OR LESS. OVERNIGHT WINDS
SHOULD BECOME LIGHT AND MORE EASTERLY AGAIN, POSSIBLY CALM AT TIMES.
A WEAK UPPER WAVE WILL MOVE IN TONIGHT, BRINGING A FEW MORE CLOUDS
ALOFT. DRY AIR SHOULD KEEP ANY FOG AT BAY OVERNIGHT.
FIRE WEATHER
ISSUED AT 331 AM EDT TUE SEP 9 2025
THE LACK OF ANY SIGNIFICANT RAINFALL OVER THE LAST SEVERAL WEEKS HAS
RESULTED IN ABNORMALLY DRY AND MINOR DROUGHT CONDITIONS TO DEVELOP
ACROSS INDIANA. WITH LITTLE TO NO RAIN IN THE FORECAST FOR THE NEXT
7 DAYS, CONFIDENCE IS INCREASING IN AN ELEVATED FIRE WEATHER THREAT
EACH AFTERNOON AS DAILY MIN RH VALUES FALL INTO THE 20% RANGE.
LOWERED AFTERNOON DEW POINTS EACH DAY THROUGH NEXT SATURDAY TO THE
NBM10TH PERCENTILE TO ACCOUNT FOR SUCH DRY CONDITIONS AND AFTERNOON
MIXING BRINGING DOWN EVEN DRIER AIR TO THE SURFACE. THE ONE FACTOR
KEEPING THE FIRE WEATHER THREAT LOWER IS THE LACK OF WIND. DESPITE
DEEP MIXING, VERY WEAK LOW LEVEL FLOW SHOULD KEEP WINDS UNDER 10 KTS
THROUGH THE PERIOD. IT IS WORTH NOTING THAT CPC HAS PLACED THE
MAJORITY OF THE MIDWEST AND MID MISSISSIPPI VALLEY IN A SLIGHT RISK
FOR EXTREME HEAT FOR SEPT 15-18TH. IF NO APPRECIABLE RAINFALL IS
OBSERVED THIS WEEKEND, THE FIRE WEATHER THREAT MAY CONTINUE TO
INCREASE AND PERSIST INTO MID MONTH. WILL CONTINUE TO MONITOR THE
EXTENDED FORECAST FOR INCREASING FIRE WEATHER CONCERNS.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...MELO
SHORT TERM...KF
LONG TERM...WHITE
AVIATION...KF
FIRE WEATHER...WHITE
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