678
FXUS63 KIWX 281609
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1209 PM EDT FRI AUG 28 2026
KEY MESSAGES
- SEASONABLE TEMPERATURES CONTINUE THROUGH SATURDAY, BUT WARMER AND
MORE HUMID CONDITIONS RETURN EARLY NEXT WEEK. HEAT INDICES
ARE EXPECTED TO REACH INTO THE MID TO UPPER 90S BY NEXT
TUESDAY.
- DRY WEATHER CONTINUES THROUGH SUNDAY WITH JUST A SLIGHT CHANCE OF
SHOWERS AND STORMS NORTH OF THE TOLL ROAD SUNDAY NIGHT.
DISCUSSION
ISSUED AT 315 AM EDT FRI AUG 28 2026
AN OVERALL QUIET WEATHER PERIOD WILL CONTINUE THROUGH EARLY NEXT
WEEK. THE MAIN HIGHLIGHT WILL BE A WARMING TREND BEGINNING
SECOND HALF OF THE WEEKEND INTO TUESDAY.
LONGWAVE UPPER TROUGH FROM JAMES BAY TO NORTHEAST CONUS WILL DEPART
TO THE EAST TONIGHT WITH A SHORT WAVE MID LEVEL RIDGE EXPECTED TO
BUILD INTO THE WESTERN GREAT LAKES BY DAYBREAK SATURDAY. LINGERING
LOW LEVEL THERMAL TROUGH ASSOCIATED WITH THE UPPER TROUGH WILL
REMAIN ANCHORED LOCALLY TODAY, AND THIS SHOULD PROVIDE LARGELY A
PERSISTENCE FORECAST IN TERMS OF MAX TEMPS THIS AFTERNOON
(UPPER 70S TO LOWER 80S). SOME VERY WEAK SFC BASED INSTABILITY
IS EXPECTED FAR SOUTH/SOUTHEAST, BUT LARGE SCALE SUBSIDENCE
SHOULD PREVENT ANY AFTERNOON SHOWER DEVELOPMENT TODAY. AN
EXPANSIVE LOW LEVEL ANTICYCLONE FROM SOUTHEAST CANADA TO THE MID
MS RIVER VALLEY WILL KEEP A LIGHT WIND FIELD IN PLACE TODAY. A
WEAK LAKE BREEZE MAY DEVELOP DUE TO THIS WEAK GRADIENT BUT
SHOULD BE TEMPERED BY MINIMUM LAND/LAKE TEMPERATURE
DIFFERENTIALS.
THE WESTERN PERIPHERY OF THIS ANTICYCLONE WILL LINGER ACROSS THE
REGION TONIGHT INTO SATURDAY. GIVEN RELATIVELY DRY AIRMASS IN PLACE,
CLEAR SKIES, AND LIGHT WINDS, EXPECTING ANOTHER NIGHT OF GOOD
RADIATIONAL COOLING WITH A POTENTIAL OF SOME SHALLOW PATCHY FOG.
SHEARED VORTICITY MAXIMUM ASSOCIATED WITH PACIFIC JET
ACCOMPANYING INCOMING UPPER LEVEL RIDGING SHOULD PROMOTE SOME
INCREASING HIGH CLOUDS LATE TONIGHT INTO EARLY SATURDAY.
LOW LEVEL WARM ADVECTION WILL COMMENCE ON SATURDAY, BUT LINGERING
EFFECTS FROM WESTERN EXTENT OF LOW LEVEL ANTICYCLONE SHOULD KEEP
ADVECTIVE FIELDS WEEK. THIS SHOULD RESULT IN ONLY A FEW DEGREES OF
WARMING FOR SATURDAY IN COMPARISON TO THAT OF TODAY. STRONGER LOW
LEVEL SOUTHWESTERLIES WILL SHIFT EAST INTO THE LOCAL AREA SATURDAY
NIGHT INTO SUNDAY. THE STRONGEST MOISTURE TRANSPORT WILL LIKELY BE
MID LEVEL IN NATURE LATE SATURDAY. CONVECTION IS LIKELY TO DEVELOP
DURING THE DAY SATURDAY ACROSS THE UPPER MS VALLEY AT THE NOSE OF
THE STRONGER LOW LEVEL FLOW, BUT GIVEN LACKLUSTER DOWNSTREAM LOW
LEVEL MOISTURE PROFILES LOCALLY, CURRENTLY NOT EXPECTING
MEASURABLE PRECIP AS FAR EAST AS LOCAL AREA SATURDAY NIGHT INTO
EARLY SUNDAY AS AN ACCOMPANYING SHORT WAVE TRACKS INTO THE AREA.
SUNDAY WILL BE NOTICEABLY WARMER AS STRONGER SOUTHWEST LOW
LEVEL FLOW ALLOWS PLAINS THERMAL RIDGE TO SHIFT REACH THE
SOUTHERN GREAT LAKES.
INCOMING UPPER LEVEL RIDGE SHOULD BE SLIGHTLY DAMPENED BY AN
UPPER TROUGH ACROSS THE DAKOTAS LATE WEEKEND INTO MONDAY.
EASTWARD PROGRESSION OF THIS PATTERN WILL ALLOW SOME VEERING OF
LOW LEVEL FLOW AND EASTWARD ADVECTION OF RICHER LOW LEVEL
MOISTURE TO THE SOUTHERN GREAT LAKES/OHIO VALLEY BY MONDAY. IT
IS POSSIBLE THERE COULD BE ENOUGH ELEVATED INSTABILITY ACROSS
THE NORTH FOR ISOLATED SHOWER/STORM LATE SUNDAY NIGHT/EARLY
MONDAY BEFORE A MORE AGGRESSIVE PUSH OF WARMER MID LEVEL TEMPS
FOR MONDAY.
THE BEGINNING OF NEXT WORK WEEK WILL FEATURE MUCH ABOVE NORMAL
TEMPERATURES AND RELATIVELY HIGHER SFC DEW POINTS. PEAK
AFTERNOON HEAT INDICES ARE EXPECTED TO REACH LOW-MID 90S FOR
MONDAY AND POSSIBLY INTO MID-UPPER 90S FOR TUESDAY. RAIN CHANCES
SHOULD REMAIN LOW MON-TUE AS WARM MID LEVEL PROFILES LIKELY
SUPPRESS ANY SFC/NEAR SFC CONVECTION. MEDIUM RANGE GUIDANCE DOES
AGREE FAIRLY WELL THAT THE DAKOTAS UPPER TROUGH SHOULD DAMPEN
RIDGE ENOUGH BY WEDNESDAY TO ALLOW FOR SOUTHWARD COLD FRONTAL
PUSH AND PERHAPS SOME CHANCE OF SHOWERS/STORMS CLIPPING SOUTHERN
GREAT LAKES WHERE LOW CHANCE POPS HAVE BEEN MAINTAINED.
DETERMINISTIC AND INDIVIDUAL ENSEMBLE MEMBERS BEGIN TO EXHIBIT
MUCH GREATER SPREAD POST-WEDNESDAY REGARDING LONGITUDINAL RIDGE
AXIS POSITION AND AMPLITUDE OF THE RIDGE. OVERALL PATTERN
SUPPORTS CONTINUATION OF ABOVE NORMAL TEMPERATURES THOUGH MUCH
OF NEXT WEEK, BUT EXTENT OF HEAT AND STORM CHANCES STILL OF
LOWER CONFIDENCE TOWARD END OF THIS FORECAST VALID PERIOD GIVEN
THIS UNCERTAINTY IN DETAILS WITH LONGWAVE PATTERN.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1208 PM EDT FRI AUG 28 2026
HIGH PRESSURE WILL CONTINUE TO PROMOTE VFR CONDITIONS AND LIGHT
WINDS THROUGH THE TAF CYCLE. THERE MAY BE SOME PATCHY, SHALLOW,
BR FORMATION AGAIN TOWARD DAYBREAK SATURDAY, THOUGH COVERAGE
AND POINT CHANCES FOR VIS RESTRICTIONS REMAIN TOO LOW FOR A
MENTION.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...MARSILI
AVIATION...STEINWEDEL
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