879
FXUS63 KIWX 041111
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
711 AM EDT THU JUN 4 2026
KEY MESSAGES
- DRY WITH VARIABLE CLOUD COVER TODAY AND TONIGHT. HIGHS WILL
CLIMB INTO THE MID TO UPPER 80S, WITH BREEZY SOUTHWEST WINDS
IN THE AFTERNOON. LOWS TONIGHT FALL INTO THE 60S.
- THERE ARE CHANCES (GREATER THAN 60 PERCENT) FOR SHOWERS AND
THUNDERSTORMS FRIDAY AFTERNOON INTO SATURDAY EVENING. LESSER
CHANCES (20-45 PERCENT) EXPECTED SUNDAY INTO TUESDAY,
ESPECIALLY SOUTH OF US 30 AND WEST OF US 31.
- THERE IS A MARGINAL RISK FOR STRONG TO SEVERE STORMS IN MOST
AREAS FRIDAY AFTERNOON INTO SATURDAY EVENING, WITH A SLIGHT
RISK IN NW OH ON SATURDAY AFTERNOON. DAMAGING WINDS AND LARGE
HAIL ARE THE MAIN THREATS IN THE STRONGEST STORMS. CONFIDENCE
IS LOW AT THIS TIME.
DISCUSSION
ISSUED AT 428 AM EDT THU JUN 4 2026
UPPER LEVEL RIDGE REMAINS IN PLACE TODAY AND TONIGHT, WITH SURFACE
HIGH PRESSURE CENTER SHIFTING FURTHER SOUTHEAST. LIGHT AND VARIABLE
WINDS THIS MORNING WILL PICK UP OUT OF THE S-SW THROUGH THE DAY AS
PRESSURE GRADIENT TIGHTENS WITH APPROACHING TROUGH, WITH GUSTS UP TO
AROUND 15-20 MPH (STRONGEST WEST OF IN-15). EXPECT PARTLY TO MOSTLY
SUNNY SKIES IN GENERAL, THOUGH THERE COULD BE A FEW CLOUDIER PERIODS
WITH INCOMING HIGH CLOUDS TO THE WEST THIS MORNING INTO THE EARLY
AFTERNOON (KORD/KMDW/KMKE SHOWING BKN250 AS OF THIS WRITING), BUT
OVERALL WE'LL SEE A LOT OF SUN AND DECENT MIXING. INITIALLY WAS A
BIT CONCERNED RE: FIRE WEATHER GIVEN THE SLIGHT UPTICK IN WINDS WITH
MINIMUM AFTERNOON HUMIDITIES FORECASTED IN THE 25-35 PERCENT RANGE
TODAY (AFTER YESTERDAY WHERE WE SAW AFTERNOON RH BOTTOM OUT IN THE
15-25 PERCENT RANGE; DEWPOINTS IN THE MID-UPPER 30S, LOW 40S). HIGHS
WILL ALSO BE WARMER THAN YESTERDAY, WITH MOST LOCATIONS REACHING AT
LEAST THE MID 80S. HOWEVER, MODELS SUGGEST SOME WEAK MOISTURE
ADVECTION IN THE LOW LEVELS TOWARDS THIS AFTERNOON WHEN WE WOULD
NORMALLY DROP TO OUR MINIMUM-SO HAVE DEWPOINTS INITIALLY BEGIN
DROPPING INTO THE LOW 50S WITH MIXING ONLY TO START CLIMBING
BACK INTO THE MID-UPPER 50S TOWARDS THE LATE AFTERNOON AND
EVENING. HELD OFF ON ANY SPS FOR ELEVATED FIRE DANGER IN
COLLABORATION WITH NEIGHBORING OFFICES.
FRIDAY INTO SATURDAY WE'LL SEE OUR BEST CHANCES FOR RAIN THIS WEEK
WITH A MID LEVEL TROUGH RIDING THE SOUTHWARD SHIFTING RIDGE. FLOW IS
SOMEWHAT ZONAL FOR US DEPENDING ON THE STRENGTH OF THE WAVE AS IT
MOVES THROUGH (FOCUS IS FURTHER NORTH IN LOWER MI). A SURFACE TROUGH
WILL MOVE THROUGH (POSSIBLE LOW PER SOME MODELS OVER LOWER MI) ON
FRIDAY AFTERNOON INTO SATURDAY, WITH INCREASED MOISTURE TRANSPORT ON
A 35-40KT LLJ. PRECIPITATION IS LIKELY TO HOLD OFF UNTIL LATER FRI
AFTERNOON/EVENING WITH BETTER MOISTURE TRANSPORT. SPC HAS PORTIONS
OF OUR AREA (ALONG/NORTH OF US 24) IN A MARGINAL RISK FOR STRONG-
SEVERE STORMS DURING THE LATE AFTERNOON AND OVERNIGHT PERIOD. MLCAPE
AHEAD OF THE TROUGH LOOKS TO BE AROUND 500-1000 J/KG FURTHER
WEST...WITH WEAK MID LEVEL LAPSE RATES. EXPECT STEEPENING LAPSE
RATES INTO THE OVERNIGHT, IN ADDITION TO INCREASING 0-6KM BULK SHEAR
AS THE WAVE MOVES THROUGH (25-40 KNOTS POSSIBLE). PER SPC, HAVE 5%
PROBABILITIES FOR BOTH DAMAGING WIND/LARGE HAIL. CONFIDENCE IS LOWER
IN THIS PERIOD RE: SEVERE POTENTIAL GIVEN UNFAVORABLE OVERNIGHT
TIMING, BUT CERTAINLY FREQUENT LIGHTNING AND HEAVY DOWNPOURS ARE
LIKELY.
SATURDAY MORNING/AFTERNOON ANOTHER WAVE MOVES THROUGH, WHICH
SPC HAS OUR AREA IN A MARGINAL TO SLIGHT RISK FOR SEVERE STORMS.
THIS IS LIKELY OUR BETTER POTENTIAL (SLIGHT IN NW OH) GIVEN MORE
FAVORABLE TIMING, AND 35 TO 40 KNOTS OF 0-6KM BULK SHEAR. CERTAINLY
A CONDITIONAL THREAT AS IT WILL DEPEND ON HOW THINGS EVOLVE
OVERNIGHT/IN THE MORNING AND HOW MUCH INSTABILITY WE CAN REGAIN
THROUGH THE DAY. DAMAGING WINDS/LARGE HAIL ARE BOTH MAIN THREATS, IN
ADDITION TO HEAVY RAIN AND LIGHTNING.
DEPENDING ON WHERE A SURFACE COLD FRONT ENDS UP ON SUNDAY AM/PM, WE
COULD SEE SOME STORMS SOUTH OF US 24 SUNDAY AFTERNOON-BUT CONFIDENCE
IS LOW AT THIS TIME. ADDITIONAL POTENTIAL FOR SHOWERS/STORMS
CONTINUE THROUGH TUESDAY, THOUGH THIS IS FOCUSED FURTHER WEST OF IN-
15 AND SOUTH OF US 30.
HIGH TEMPERATURES WILL LINGER IN THE MID-UPPER 80S FOR THE
MOST PART THROUGH EARLY NEXT WEEK, WITH LOWS IN THE 50S, 60S.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 709 AM EDT THU JUN 4 2026
VFR CONDITIONS EXPECTED AT THE TERMINALS THIS PERIOD WITH NORTHERN
INDIANA STILL BENEATH AN UPPER LEVEL RIDGE/SURFACE HIGH. AS WE HEAD
INTO THIS AFTERNOON/EVENING, SURFACE PRESSURE GRADIENT BEGINS
TO TIGHTEN SLIGHTLY AHEAD OF AN APPROACHING SURFACE TROUGH/MID
LEVEL WAVE. LIGHT/VARIABLE WINDS INCREASE AND BECOME MORE
SOUTHWESTERLY THROUGH THE DAY. MIXING IN THE AFTERNOON WILL
BRING GUSTS UP TO AROUND 15-20KTS AT TIMES (HIGHEST/MORE
FREQUENT AT KSBN). OTHERWISE, EXPECT VARIABLE CLOUD COVER AROUND
25-30KFT (PER UPSTREAM OBS, SCT/BKN AT TIMES).
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...MCD
AVIATION...MCD
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