480
FXUS63 KIWX 250612
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
212 AM EDT THU JUN 25 2026
KEY MESSAGES
- RAIN SHOWERS ENDING EARLY THIS MORNING.
- 20% CHANCE OF AN ISOLATED THUNDERSTORM THIS AFTERNOON.
- RAIN, HEAVY AT TIMES, ARRIVES FROM SOUTHWEST TO NORTHEAST ON
FRIDAY.
- BECOMING HOT AND HUMID NEXT WEEK WITH HIGHS IN THE 90S AND
HEAT INDICIES NEAR 100 AS EARLY AS MONDAY.
DISCUSSION
ISSUED AT 210 AM EDT THU JUN 25 2026
A NARROW WARM SECTOR HAS CONTINUED TO PERMIT SHOWERS AND ISOLATED
THUNDERSTORMS PERSIST EARLY THIS MORNING. THIS ACTIVITY WILL TAPER
OFF OVER THE NEXT COUPLE OF HOURS AND IN ITS WAKE, STRATUS AND
PATCHY FOG WILL TAKE SHAPE. UPSTREAM OBSERVATIONS HAVE POCKETS OF
1/4 MILE VISIBILITY, BUT WITH SURFACE WIND FORECAST TO BE NEAR 5
KNOTS, LOW CLOUDS SHOULD BE THE PRIMARY SKY COVER EARLY THIS
MORNING.
SURFACE LOW OVER SOUTHERN WISCONSIN SLIDES ESE WITH ITS TRAILING
COLD FRONT BECOMING DRAPED OVER THE AREA TODAY, SERVING AS THE FOCUS
FOR ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON. ALOFT, WE'RE
BENEATH THE RIGHT EXIT REGION OF A 60-KNOT 500-MB JET WHICH IS NOT
THE IDEAL PLACEMENT FOR UPPER-LEVEL SUPPORT. FORECAST SOUNDINGS ARE
RATHER DRY AS WELL, HELPING TO LIMIT THE OVERALL COVERAGE OF STORMS.
STEEP LOW-LEVEL LAPSE RATES (NEARLY 9C/KM) DO PRESENT AN ISOLATED
DOWNBURST RISK FROM ANY FEISTY STORMS IN WHAT IS OTHERWISE A WEAKLY
SHEARED ENVIRONMENT.
TURNING TO FRIDAY, THE AFORMENTIONED FRONT CREEPS NORTH AS LOW
PRESSURE EMERGES FROM THE CENTRAL PLAINS AND SENDS AN AREA OF RAIN
THROUGH CENTRAL INDIANA AFTER DAYBREAK. THE GREATEST RAINFALL TOTALS
ARE SHAPING UP TO BE ALONG THE SOUTH OF US 30, A SLIGHT NORTHWARD
SHIFT THAN PREVIOUSLY THOUGHT AS STEERING HIGH PRESSURE OFF THE
SOUTHEAST US APPEARS SOMEWHAT STRONGER, AND INCOMING CANADIAN HIGH
PRESSURE LESS OF A FACTOR. RAIN TOTALS COULD EXCEED 1" BEFORE
TAPERING OFF FROM WEST TO EAST AFTER SUNSET.
LOOKING PRIMARILY DRY FOR THE WEEKEND AS HIGH PRESSURE BRIEFLY TAKES
HOLD OVER THE EASTERN GREAT LAKES. CANNOT COMPLETELY RULE OUT A
PERIOD OF SHOWERS AND THUNDERSTORMS SUNDAY MORNING, BUT FORCING IS
MURKY WITH A BUILDING RIDGE.
THE PRIMARY STORY IN THE LONG-TERM IS THE INCREASING HEAT AND
HUMIDITY AS A STRONG RIDGE BECOMES CENTERED OVER THE SOUTHERN
MISSISSIPPI VALLEY. SPURIOUS POPS WILL NEED TO BE ADDRESSED AT TIMES
FROM THE IN-HOUSE BLEND, BUT THERE WILL BE INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS (RIDGE-RUNNING MCS' PERHAPS) SHOULD THE
RIDGE BREAK DOWN LATE-WEEK. UNTIL THEN, HIGHS IN THE 90S WITH A HEAT
INDEX NEAR 100.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1238 AM EDT THU JUN 25 2026
SHOWERS AND ISOLATED THUNDERSTORMS ARE DEPARTING KSBN BUT
CONTINUE AT KFWA. LIGHTNING IS ON THE DECLINE FOR A SMALL
SEGMENT OF STORMS SSW OF KASW, BUT IS OTHERWISE DESTINED FOR
KFWA. BEHIND THIS ACTIVITY, STRATUS AND PERHAPS BR IS FORECAST
TO DEVELOP AS NORTHWEST FLOW AND SUBSIDENCE TAKE SHAPE.
CONFIDENCE IS HIGHER AT KSBN FOR IFR STRATUS, WHILE CONFIDENCE
IS LOWER AT KFWA DUE TO A LATER DEPARTURE TIME OF -SHRA THIS
MORNING.
DECREASING CLOUDS AFTER DAYBREAK AND WESTERLY WIND INCREASING.
ISOLATED THUNDERSTORMS TOWARD KFWA IN THE AFTERNOON, BUT
COVERAGE APPEARS TO BE SPARSE AND THE ONSET LOCATION UNCERTAIN.
WILL CONTINUE TO MONITOR TRENDS IN HIGH RESOLUTION GUIDANCE AND
PROVIDE AN UPDATE AT 12Z. HIGH CONFIDENCE IS DRY CONDITIONS THIS
AFTERNOON AT KSBN.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...BROWN
AVIATION...BROWN
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