167
FXUS63 KIWX 272250
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
650 PM EDT SAT JUN 27 2026
KEY MESSAGES
- ISOLATED (15-20%) SHOWERS POSSIBLE THIS EVENING MAINLY
ALONG/SOUTH OF ROUTE 24.
- DANGEROUS HEAT AND HUMIDITY IS STARTING MONDAY AS HEAT
INDICES CLIMB ABOVE 100 DEGREES EACH AFTERNOON WITH LITTLE
COOLING AT NIGHT.
DISCUSSION
ISSUED AT 126 PM EDT SAT JUN 27 2026
AREAS OF SHOWERS AND STORMS CONTINUE TO DEVELOP ALONG A STATIONARY
BOUNDARY NEAR THE OHIO RIVER. A FEW CAMS STILL TRY TO DEVELOP WIDELY
SCATTERED SHOWERS ACROSS SOUTHERN PARTS OF THE FORECAST AREA ALONG
AN ELEVATED WARM FRONT DRAPED IN THIS SAME AREA. CU FIELD HAS BEEN
RATHER UNIMPRESSIVE SO FAR, BUT A FEW HINTS OF SOME MORE
AGITATED CU AND WEAK RETURNS MAY BE STARING TO TAKE SHAPE. AS A
RESULT, WILL MAINTAIN A SLGT CHC THROUGH 00Z BEFORE ENDING WITH
LOSS OF HEATING.
UPPER LEVEL LOW PRESSURE IN THE NW US WILL DIG FURTHER AND STALL
OUT, WITH STRONG RIDGING ALOFT STILL ON TRACK TO BRING A BLAST OF
HOT AND HUMID CONDITIONS. SUNDAY WILL SEE MORE SEASONABLE HIGHS IN
THE 80S WITH THE HUMIDITY INCREASING THROUGH THE AFTERNOON. HEAT
INDICES WILL START TO CLIMB, BUT REMAIN WELL BELOW HEADLINE
THRESHOLDS. AN MCS IS EXPECTED TO DEVELOP IN MN SUNDAY AND PROPAGATE
ESE ALONG THE ADVANCING WARM FRONT. SOME MODELS TRY TO BRING SOME
REMNANTS OF THIS IN SUNDAY NIGHT, BUT DOESN'T SEEM OVERLY LIKELY SO
WILL REMOVE ANY SPURIOUS POPS LATE SUN NIGHT RELATED TO THIS.
BY MONDAY, UPPER LEVEL RIDGING WILL BEGIN TO TAKE HOLD WITH THE WARM
FRONT WELL NORTH OF THE REGION ALLOWING FOR THE FIRST OF WHAT WILL
MOST LIKELY BE SEVERAL DAYS OF DANGEROUS HEAT INDICES. MONDAY WILL
BE MORE "MARGINAL" WITH VALUES EITHER SIDE OF THE 100 DEGREE
THRESHOLD, BUT TUE-THU SEEM RATHER STRAIGHT FORWARD WITH EXPECTED
VALUES OF 100 TO 105 (HIGHER?). ALTHOUGH ON ANY GIVEN DAY WE WILL
REMAIN AT ADVISORY VS WARNING LEVELS, THE LONGEVITY OF THE EVENT AND
LACK OF COOLING AT NIGHT BRINGS GREATER RISKS TO THOSE SENSITIVE TO
THE HEAT AND HUMIDITY. COORDINATION TOOK PLACE ON HOISTING A
EXCESSIVE HEAT WATCH MON-THU, BUT SEVERAL CONCERNS EXISTED MAINLY
WITH EXACTLY HOW HIGH DEWPOINTS WILL GET AND TO OUR WEST A POTENTIAL
FOR CONVECTIVE COMPLEXES ON THE WESTERN FRINGES OF THE RIDGE. WILL
DEFER ANY HEADLINES FOR NOW AS A RESULT AND CONTINUE TO PUSH
MESSAGING. ON A SIDE NOTE, WHILE NOT "CRITERIA" FOR HEAT HEADLINES,
THE NWS HEATRISK GUIDANCE HIGHLIGHTS THE MAJOR CATEGORY (MON AND
TUE) AND EXTREME FOR WED AND THU). FOR MORE DETAILS ON WHAT GOES
INTO THIS GUIDANCE AND A LOOK AT THE LATEST GUIDANCE, GO TO
WWW.WPC.NCEP.NOAA.GOV/HEATRISK.
WITH REGARDS TO CONVECTIVE CHANCES, AS ALREADY MENTIONED IN THE PAST
AN UNSTABLE ATMOSPHERE WILL BE IN PLACE BUT LACK OF TRIGGERS AND A
VERY CAPPED MID LEVEL WILL LIKELY PREVENT MUCH ACTIVITY INTO WED AND
LIKELY THU AS WELL. NBM BRINGS SOME LOW POPS IN AS EARLY AS THU IN
THE FAR NORTH AND THEN MORESO INTO THE UPCOMING HOLIDAY WEEKEND.
WILL DEAL WITH THOSE DETAILS IN THE COMING DAYS.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 650 PM EDT SAT JUN 27 2026
STALLED FRONTAL BOUNDARY REMAINS JUST SOUTH OF THE AREA AND ENE
FLOW HERE IS MAINTAINING JUST ENOUGH LOW LEVEL DRY AIR TO
SUPPORT VFR CONDITIONS. THIS WILL LIKELY CONTINUE THROUGH MUCH
OF THE PERIOD. HOWEVER, SOME MVFR VISIBILITIES AND CEILINGS WILL
BE POSSIBLE AT KFWA SUNDAY MORNING AS THIS FRONT BEGINS TO
SLOWLY LIFT NORTH. CONFIDENCE IS NOT HIGH SO JUST MAINTAINED A
TEMPO 5SM BR MENTION FOR NOW. SOME MVFR CEILINGS MAY BE POSSIBLE
LATER SUNDAY MORNING AS WELL, THOUGH. MVFR CAN'T BE ENTIRELY
RULED OUT AT KSBN BUT CHANCES ARE LOWER.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...FISHER
AVIATION...AGD
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