441
FXUS63 KIND 211903
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
303 PM EDT SAT JUN 21 2025
KEY MESSAGES
- HEAT ADVISORY IN EFFECT TODAY THROUGH TUESDAY
- HOTTEST CONDITIONS OF THE SEASON THUS FAR INTO MUCH OF NEXT WEEK,
WITH HEAT INDEX VALUES 100-105 DEGREES EACH AFTERNOON
- SCATTERED THUNDERSTORMS POSSIBLE MID-WEEK INTO NEXT WEEKEND
SHORT TERM (THIS EVENING THROUGH SUNDAY)
ISSUED AT 303 PM EDT SAT JUN 21 2025
THE WELL ADVERTISED FIRST HEAT WAVE OF THE SUMMER IS UNDERWAY ACROSS
THE ENTIRE REGION. TEMPERATURES HAVE REACHED THE 90 DEGREE MARK FOR
MANY LOCATIONS WITHIN CENTRAL INDIANA, INCLUDING THE INDIANAPOLIS
FOR THE FIRST TIME THIS SEASON. HOT AND HUMID CONDITIONS PERSIST FOR
THE REST OF THE DAY, WITH THE ONLY "RELIEF" BEING GUSTY WINDS OF 20-
25 MPH THROUGH AROUND SUNSET. DO NOT EXPECT MUCH RELIEF AT NIGHT
OVER THE NEXT WEEK AS OVERNIGHT LOWS MAY NOT FALL BELOW THE MID 70S!
UPPER RIDGING WILL CONTINUE TO BUILD OVER THE OHIO VALLEY AND GREAT
LAKES REGION THE NEXT SEVERAL DAYS, KEEPING THE HOT AND HUMID
AIRMASS IN PLACE. LOW LEVEL RIDGING SHIFTS SLIGHTLY WESTWARD
TOMORROW, PUSHING THE CORE OF THE LOW LEVEL JET FURTHER TO THE WEST
AS WELL. EXPECT DEEP LOW LEVEL MIXING TOMORROW AFTERNOON, HOWEVER
NOT EXPECT AS STRONG OF GUSTS TOMORROW DUE TO THE WEAKER LOW LEVEL
JET ALOFT. EACH DAY DURING THIS HEAT WAVE MAY BE A FEW DEGREES
WARMER THAN THE PREVIOUS AS THE GROUND RAPIDLY DRIES OUT. WENT A
LITTLE ABOVE GUIDANCE FOR HIGHS TOMORROW WITH FORECAST HIGHS
REACHING THE MID 90S FOR ALL LOCATIONS. THE HEAT ADVISORY REMAINS IN
EFFECT AS HIGH HUMIDITY VALUES COMBINED WITH THE HOT TEMPERATURES
WILL RESULT IN HEAT INDEX VALUES OF 100-105 DEGREES DURING PEAK
HEATING OF THE DAY.
COPY/PASTE THIS FORECAST FOR THE NEXT SEVERAL DAYS INTO AT LEAST
EARLY NEXT WEEK AS THERE IS HIGH CONFIDENCE IN THIS HEAT WAVE
PERSISTING.
LONG TERM (SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 303 PM EDT SAT JUN 21 2025
..PROLONGED HEAT AND HUMIDITY EXPECTED INTO LATE NEXT WEEK
SUNDAY NIGHT THROUGH TUESDAY...
STRONG, HOT AND HUMID, SUBTROPICAL RIDGE WILL BE WELL ESTABLISHED
OVER MOST OF THE EASTERN CONUS BY THE TIME THE LONG TERM PERIOD
BEGINS, WITH ITS CUT-OFF 594 DM H500 HEIGHT EXPANDING FROM THE
OZARKS TO THE NEW ENGLAND COAST. INDIANA'S PROXIMITY SLIGHTLY WEST
OF THE STACKED RIDGE'S CENTER WILL PROMOTE GENERALLY LIGHT,
SOUTHWESTERLY SURFACE FLOW THROUGH THE EARLY WEEK...THAT WILL
MAINTAIN OPPRESSIVE DEWPOINTS AND CORRESPONDING UNSEASONABLY HIGH
DAILY MINIMUM TEMPS...IN THE LOW TO MID-70S.
WIDESPREAD LOW 90S CAN BE EXPECTED BOTH AFTERNOONS...COURTESY OF THE
HIGHER STARTING POINT, H850 READINGS AROUND 20 CELSIUS, AND
GENERALLY AMPLE AMOUNTS OF SUMMER SOLSTICE SUNSHINE. MAXIMUMS MAY
NEAR 95F ALONG THE WABASH VALLEY AS WELL AS TYPICALLY HOTTER ARES
ACROSS SOUTHERN ZONES. HEAT INDEX VALUES TO PEAK NEAR OR SLIGHTLY
ABOVE 100 DEGREES BOTH DAYS FOR MOST LOCATIONS...ALTHOUGH GREATER
CONCERN WILL BE OVERNIGHT HEAT INDICES NOT FALLING BELOW THE MID-
70S, AS THIS STREAK WILL NEAR 4 DAYS STRAIGHT BY LATE TUESDAY NIGHT.
BIGGEST CHANGE IN MOST RECENT GUIDANCE IS THE UPPER RIDGE'S LESS-
AMPLIFIED GEOMETRY, WITH A POTENTIAL WEAK SURFACE BOUNDARY SLIDING
FROM THE SOUTHERN GREAT LAKES TO THE NORTHERN MIDWEST AROUND THE
TUESDAY-TUESDAY NIGHT TIMEFRAME. DOUBT THIS COOL FRONT MAKES ANY
HEADWAY INTO THE LOCAL CWA, YET PARTLY CLOUDY SKIES AND PERHAPS
BRIEFLY SCATTERED SHOWERS/T-STORMS FROM ASSOCIATED MODEST LIFT...MAY
BE IN ORDER LATE TUESDAY NEAR NORTHWEST/FAR NORTHERN COUNTIES...
WHICH COULD LOWER HEAT INDEX VALUES 5-10 DEGREES FROM CURRENT
EXPECTATIONS FOR A FEW SPOTS.
WEDNESDAY THROUGH SATURDAY...
ABOVE NORMAL HEAT AND HUMIDITY IS EXPECTED TO CONTINUE THROUGH THE
SECOND HALF OF THE WEEK, ALTHOUGH LIKELY WIDELY SCATTERED DIURNAL
CONVECTION SHOULD PROVIDE SUB-90F AFTERNOON HIGHS FOR A FEW
LOCATIONS, ESPECIALLY BY THE END OF THE WEEK. NO NOTICEABLE RELIEF
IS EXPECTED FROM THE HIGH HUMIDITY, HOWEVER, AMID WEST-SOUTHWESTERLY
FLOW UNDER PRECIPITABLE WATER VALUES AROUND 1.80 INCHES...ALTHOUGH
THE TROPICAL FLOW SHOULD HAVE MORE OF A DAYTIME BREEZE AROUND THE
THURSDAY-FRIDAY TIMEFRAME...WITH LOW PRESSURE NEAR THE UPPER MIDWEST
PROVIDING A MODEST GRADIENT. CORRESPONDING WEAK FORCING AND AMPLE
AFTERNOON CAPE MAY SET OFF PULSE CELLS, THAT SHOULD HAVE NEXT TO NO
SHEAR TO UTILIZE.
THE RANGE OF HEAT INDEX VALUES SHOULD BE SIMILAR TO EARLY WEEK
LEVELS, WITH MORNING MINIMUMS STILL IN THE MID-70S, ALTHOUGH
AFTERNOON MAXIMUMS MAY A TOUCH LOWER WITH ONLY UPPER 90S IN THE
REGION'S COOLER LOCALES. THE HEAT ADVISORY MAY BE EXTENDED THROUGH
AT LEAST THE MID-WEEK IF AND WHEN CONFIDENCE INCREASES IN CRITERIA
THRESHOLDS BEING REACHED.
AVIATION (18Z TAF ISSUANCE)
ISSUED AT 143 PM EDT SAT JUN 21 2025
IMPACTS:
- WIND GUSTS UP TO 20-25KT FROM 200-210 DEGREES BETWEEN 15Z AND 00Z
THIS AFTERNOON/EVENING
DISCUSSION:
MAINLY VFR CONDITIONS EXPECTED THROUGH THE NEXT SEVERAL DAYS AS
RIDGING ALOFT AND HIGH PRESSURE BECOME THE DOMINANT WEATHER
INFLUENCE LOCALLY. SATELLITE IMAGERY AND OBSERVATIONS SHOW DIURNAL
CUMULUS OVER THE STATE AROUND 3000FT AGL. CLOUDS SHOULD REMAIN
SCATTERED FOR THE MOST PART, BUT WOULD NOT BE SURPRISED TO SEE A
BROKEN DECK AT TIMES. KEEPING SCT030 FOR THE TAFS FOR NOW AS
CONFIDENCE IS LOW THAT THAT CLOUD COVERAGE WILL INCREASE TO WARRANT
BKN.
THE PRIMARY IMPACT DURING THIS PERIOD WILL BE WIND GUSTS OF 20-25
KTS INTO THE EARLY EVENING AT ALL SITES. THESE GUSTS WILL SUBSIDE IN
TYPICAL DIURNAL FASHION DURING THE EVENING, WITH WINDS TOMORROW
NIGHT REMAINING SOUTHERLY (190-200 DEGREES) AT 7-11KT, AGAIN
PREVENTING ANY SIGNIFICANT FOG.
EXPECT A SIMILAR FORECAST FOR TOMORROW AS THE PATTERN LARGELY
REMAINS THE SAME. AFTERNOON WIND GUSTS TOMORROW AFTERNOON SHOULD
REMAIN BELOW 20 KTS AS THE LOW LEVEL JET WILL BE WEAKER.
IND WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY UNTIL 8 PM EDT TUESDAY FOR INZ021-028>031-035>049-
051>057-060>065-067>072.
SHORT TERM...CM
LONG TERM...AGM
AVIATION...CM
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