913
FXUS63 KIWX 271019
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
619 AM EDT FRI JUN 27 2025
KEY MESSAGES
- HEAT ADVISORY THIS AFTERNOON FOR HEAT INDICES APPROACHING 100
DEGREES. AFTERNOON CONVECTION AND CLOUDS COULD LIMIT OVERALL
DURATION OF IMPACTS.
- SCATTERED (40 TO 50%) SHOWERS AND STORMS THIS AFTERNOON AND
EVENING WITH LOCALLY GUSTY WINDS AND VERY HEAVY RAINFALL
EXPECTED. SOMEWHAT BETTER CHANCES FOR SHOWERS AND STORMS
MONDAY AFTERNOON/EVENING (60 TO 70%)
- MORE SEASONABLE TEMPERATURES AND LOWER HUMIDITY VALUES
EXPECTED TUESDAY AND BEYOND.
DISCUSSION
ISSUED AT 321 AM EDT FRI JUN 27 2025
SHOWERS/STORMS CONTINUE TO PERCOLATE IN W/NW AREAS ON THE EDGE OF A
HIGHER CAPE GRADIENT WITH AN UNCAPPED ATMOSPHERE AND MULTIPLE
OUTFLOW BOUNDARIES ALLOWING FOR RE-DEVELOPMENT. OVERALL TRENDS
CONTINUE HEADING SLOWLY DOWN, BUT CAN'T COMPLETELY RULE OUT A FEW
SHOWERS POPPING HERE AND THERE THE REMAINDER OF THE NIGHT.
WHILE THE FORECAST AREA WILL REMAIN ON THE EDGE OF THE SPRAWLING
UPPER LEVEL RIDGE, SOME MODEST LOWERING OF HEIGHTS WILL TAKE PLACE
IN RESPONSE TO A WEAK TROUGH THAT PASSES JUST TO OUR NORTH. AT THE
SURFACE A "COOL FRONT" WILL MAKE ITS WAY ACROSS THE AREA DURING PEAK
HEATING, INTERACTING WITH AN ATMOSPHERE THAT IS RELATIVELY UNCHANGED
(1000-2000 J/KG OF MLCAPE, OVERALL SHEAR AOB 25 KTS AND MODEST LAPSE
RATES) TO RESULT IN YET ANOTHER DAY OF PULSE TYPE STORMS INITIATING
IN NW AREAS BETWEEN 18 AND 21Z AND THEN PROGRESSING SE. REMNANT
OUTFLOW BOUNDARIES COULD ALLOW FOR EARLIER DEVELOPMENT IN SOME
AREAS. WHILE THE GREATEST THREAT WILL BE LOCALLY HEAVY RAIN,
STRONGER STORMS THAT CAN ATTAIN SUFFICIENT HEIGHTS DUE TO
BOUNDARY AND STORM INTERACTIONS COULD PRODUCE POCKETS OF 50 TO
LOCALLY AS HIGH AS 65 MPH WIND GUSTS. SPC MAINTAINED THE
MARGINAL RISK (LEVEL 1 OF 5) WITH A SLIGHT RISK INTRODUCED JUST
NE OF OUR AREA CLOSER TO SLIGHTLY BETTER SHEAR.
THE ANTICIPATED CONVECTION RESULTED IN A LOT OF DISCUSSION ON
HOW HIGH HEAT INDICES CAN GET AGAIN THIS AFTERNOON. EVEN WITH
POCKETS OF STORMS THE PAST COUPLE OF DAYS, HEAT INDICES HAVE
MANAGED TO REACH EITHER SIDE OF 100 DEGREES IN MANY AREAS. SOME
MID/HIGH CLOUDS MAY EXIST THIS MORNING IN THE WEST, BUT WITH
TEMPERATURES STARTING IN THE LOW TO MID 70S IT WON'T TAKE LONG
TO WARM WELL INTO THE 80S TO NEAR 90 (ESPECIALLY SE AREAS). MUCH
DISCUSSION TOOK PLACE IN HOUSE AND WITH OTHER OFFICES AND WHILE
TRUE "HEAT ADVISORY" CRITERIA MAY FALL SHORT IN FINAL VALUES OR
DURATION, GIVEN ABOVE NOTED CONCERNS HAVE OPTED TO ISSUE ONE
MORE HEAT ADVISORY FOR THE ENTIRE AREA GIVEN THE LONGEVITY OF
THIS OVERALL HEAT WAVE.
THE FRONT WILL SAG SOUTH TONIGHT INTO SATURDAY AS THE UPPER TROUGH
SHIFTS EAST BRINGING SOMEWHAT COOLER AND LESS HUMID CONDITIONS. THE
RIDGE WILL EDGE BACK NORTH SUNDAY INTO EARLY MONDAY WITH
TEMPERATURES MAKING ONE MORE RUN AT THE UPPER 80S TO AROUND 90.
DEWPOINTS MAY REMAIN JUST LOW ENOUGH TO KEEP HEADLINES AT BAY, BUT
LATER SHIFTS CAN SORT THAT OUT. A SOMEWHAT MORE PRONOUNCED TROUGH
AND FRONT WILL FINALLY SEND TEMPERATURES BACK INTO THE 80S AND MOST
NOTICEABLE LOWER HUMIDITY VALUES TO SOMEWHAT MORE TYPICAL
LEVELS. SCATTERED TO NUMEROUS SHOWERS/STORMS ARE EXPECTED MONDAY
AFTERNOON AND EVENING WITH A LOW LIKIHOOD OF SEVERE WEATHER AT
THIS TIME.
TUESDAY THROUGH THURSDAY LOOK TO BE GENERALLY RAIN FREE AND PLEASANT
BEFORE A WARM FRONT BEGINS TO EDGE NORTH WITH SLGT CHC TO CHC POPS
AT TIMES.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 613 AM EDT FRI JUN 27 2025
ISOLATED SHOWERS CONTINUE TO FESTER EARLY THIS MORNING ON THE
WESTERN EDGE OF A MID-LEVEL MOISTURE GRADIENT ACCORDING TO WATER
VAPOR IMAGERY. THUS, A VFR SHOWER WAS ADDED TO KFWA THIS
MORNING. THESE CELLS OVER THE PAST TWO HOURS HAVE HAD VERY SHORT
LIFE CYCLES, BUT NONETHELESS, THE UPTICK IN ACTIVITY HAS ALLOWED
FOR -SHRA TO BE INTRODUCED.
NO CHANGES TO THE -TSRA FORECAST THIS AFTERNOON. COVERAGE COULD
BE ISOLATED WHICH DECREASES CONFIDENCE IN STORMS OCCURRING AT
THE TERMINALS, ESPECIALLY AT KSBN WHERE AS STATED PREVIOUSLY,
IT IS PLAUSIBLE STORMS DEVELOP EAST OF KSBN. LOW CONFIDENCE
THERE, BUT CONFIDENCE IS HIGHER THAT KFWA CAN SEE A STORM.
LASTLY, LATE IN THE PERIOD, CAN'T COMPLETELY RULE OUT A PERIOD
OF MVFR CEILINGS BEHIND THE COLD FRONT. THE IN-HOUSE BLEND
SUGGESTS A 10-20% CHANCE OF MVFR CEILINGS. FORECAST SOUNDINGS
DEPICT AN INCREDIBLY SHALLOW MOISTURE LAYER WHICH MAY PRECEDE
ANY MVFR CEILING CONCERN. WILL PASS THIS ON TO THE INCOMING
SHIFT.
IWX WATCHES/WARNINGS/ADVISORIES
IN...HEAT ADVISORY FROM NOON EDT /11 AM CDT/ TODAY TO 8 PM EDT /7
PM CDT/ THIS EVENING FOR INZ005>009-012>015-017-018-020-
022>027-032>034-103-104-116-203-204-216.
OH...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
OHZ001-002-004-005-015-016-024-025.
MI...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
MIZ078>081-177-277.
MARINE...NONE.
DISCUSSION...NORMAN
AVIATION...BROWN
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