772
FXUS63 KIWX 031742
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
142 PM EDT FRI JUL 3 2026
KEY MESSAGES
- THE EXTREME HEAT WARNING CONTINUES THROUGH THIS EVENING ACROSS NORTHWEST
OHIO, ALONG WITH PORTIONS OF NORTHERN INDIANA MAINLY EAST OF
I-69 AND SOUTH OF US 24. A HEAT ADVISORY IS IS EFFECT
ELSEWHERE. HEAT INDICES WILL RANGE FROM THE UPPER 90S TO
AROUND 105 (HIGHEST IN THE WARNING AREA).
- A NEW HEAT ADVISORY HAS BEEN ISSUED FOR AREAS MAINLY EAST OF
I-69 AND SOUTH OF US 24 THROUGH 8 PM EDT SATURDAY. PEAK HEAT
INDICES SATURDAY AFTERNOON ARE EXPECTED TO BE AROUND 100
DEGREES.
- THERE IS A SLIGHT RISK (LEVEL 2 OF 5) FOR SEVERE WEATHER
TODAY. SCATTERED STORMS ARE MOST LIKELY THIS EVENING AND
EARLY OVERNIGHT WITH DAMAGING WIND GUSTS, HEAVY RAIN, AND
LIGHTNING AS THE MAIN THREATS.
- HOT AND HUMID FOR THE 4TH OF JULY WITH 30-50% CHANCES FOR
SHOWERS AND STORMS. THERE IS A MARGINAL RISK (LEVEL 1 OF 5)
FOR SEVERE WEATHER. CONFIDENCE IS LOW BUT ISOLATED SEVERE
STORMS WILL BE POSSIBLE BETWEEN 2-11 PM EDT WITH DAMAGING WIND
GUSTS, HEAVY RAIN, AND LIGHTNING AS THE MAIN THREATS.
DISCUSSION
ISSUED AT 141 PM EDT FRI JUL 3 2026
HIGH HEAT AND HUMIDITY IS EXPECTED TO SUSTAIN SCATTERED STORMS LATER
THIS EVENING. A GROWING CUMULUS FIELD IS EVIDENT ON VISIBLE
SATELLITE IMAGERY WITH STRONG TO SEVERE STORMS SEEN ON RADAR ACROSS
PARTS OF SOUTHERN WISCONSIN AND NORTHERN ILLINOIS. HOW MUCH THE
STORMS MAINTAIN THEIR STRENGTH IS UNCERTAIN BUT THE HOT AND HUMID
AIRMASS OVERHEAD HAD LED TO AN IMPRESSIVE 3000-4000 J/KG OF SBCAPE
THIS AFTERNOON ALREADY. LATEST ITERATIONS OF THE HRRR SHOW A FEW
ISOLATED STORMS MAY DEVELOP ACROSS SOUTHWEST LOWER MICHIGAN AND
NORTHWEST INDIANA BETWEEN 21-00Z THIS EVENING, WITH ADDITIONAL
STORMS BUILDING IN BETWEEN 03-06Z ALONG OUTFLOW BOUNDARIES LEFTOVER
FROM THE IL/WI CONVECTION. SPC HAS MAINTAINED THE SLIGHT RISK (LEVEL
2 OF 5) FOR OUR FORECAST AREA. MULTICELL STORM CLUSTERS ARE EXPECTED
TO POSE A DAMAGING WIND THREAT THIS EVENING INTO TONIGHT. FORECAST
SOUNDINGS DEPICT INVERTED V PROFILES WITH DCAPE ABOVE 1000 J/KG,
WHICH ALSO INDICATES A FAVORABLE ENVIRONMENT FOR MICROBURSTS.
OTHER FAVORABLE PARAMETERS INCLUDE LOW LEVEL LAPSE RATES IN
EXCESS OF 8 C/KM AND PWATS AROUND 1.5". IN ADDITION TO THE
DAMAGING WIND THREAT, HEAVY RAINFALL AND LIGHTNING WILL BE
HAZARDS AS WELL.
AS THE UPPER LEVEL RIDGE CONTINUES TO FLATTEN,GIVEN A LOW SHEAR
ENVIRONMENT AND POTENTIAL FOR LEFTOVER OUTFLOW BOUNDARIES IN THE
AREA, HAVE CONTINUED TO MAINTAIN DAILY PERIODIC CHANCES FOR STORMS
THROUGH THE HOLIDAY WEEKEND. HOW THE PATTERN EVOLVES IS DEPENDENT ON
MESOSCALE AND EVEN SOME STORM SCALE PARAMETERS, WHICH MAKES
FORECASTING BEYOND JUST 6 TO 12 HOURS AHEAD OF TIME VERY TRICKY AND
UNCERTAIN. WHILE THERE IS MEDIUM CONFIDENCE ON TODAY'S SETUP,
EVERYTHING BEYOND THIS EVENING IS MURKY AND LOW CONFIDENCE IN EXACT
TIMING AND LOCATION OF STORMS.
JULY 4TH WILL NOT BE A COMPLETE WASHOUT, HOWEVER, THERE IS STILL A
MARGINAL RISK (LEVEL 1 OF 5) FOR SEVERE WEATHER. SATURDAY MARKS THE
BEGINNING OF OUR SLIGHT COOL DOWN, WITH HIGHS IN THE MID 80S TO NEAR
90 DEGREES. HUMID CONDITIONS STICK AROUND FOR THE HOLIDAY THOUGH
WITH DEWPOINTS IN THE LOW TO MID 70S. A HEAT ADVISORY HAS BEEN
ISSUED FOR OUR SOUTHEAST HALF, INCLUDING FROM CASS COUNTY, IN UP TO
WHITLEY COUNTY, IN UP TO WILLIAMS COUNTY, OH UNTIL 8 PM EDT SATURDAY
WHERE PEAK HEAT INDICES WILL BE AROUND 100 DEGREES. IN ADDITION TO
THE CONTINUED HEAT AND HUMIDITY, THIS MODERATELY UNSTABLE AIRMASS
SHOULD AID IN AT LEAST ISOLATED THUNDERSTORM DEVELOPMENT BETWEEN 2-
11 PM EDT SATURDAY. THIS SETUP WILL BE HIGHLY DEPENDENT ON MORNING
CONVECTION, LEFTOVER CLOUD DEBRIS, AND IF/WHERE THERE ARE ANY OLD
OUTFLOW BOUNDARIES IN THE AREA. ISOLATED DAMAGING WIND GUSTS WOULD
BE THE MAIN THREAT AGAIN IN ANY STRONG TO SEVERE STORMS; EVEN
IF STORMS STAY SUB-SEVERE, HEAVY RAIN AND LIGHTNING WILL STILL
BE HAZARDS. IF YOU HAVE ANY OUTDOOR PLANS FOR THE 4TH OF JULY,
STAY SAFE AND STAY COOL!
A TROUGH EJECTING OUT OF THE WESTERN US COULD BRING ADDITIONAL
CHANCES FOR SHOWERS AND STORMS ON SUNDAY. THE EARLY TO MIDDLE PART
OF NEXT WEEK LOOKS MOSTLY DRY AS A HIGH PRESSURE SYSTEM SETS UP OVER
THE MIDWEST AND GREAT LAKES.WHILE IT MAY BE SLIGHTLY 'COOLER' INTO
EARLY NEXT WEEK WITH HIGHS IN THE 80S, THE LONG TERM PATTERN
CONTINUES TO FAVOR ABOVE NORMAL TEMPERATURES THROUGH MID JULY.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 125 PM EDT FRI JUL 3 2026
THE RIDGE OF HIGH PRESSURE ACROSS THE SOUTHEASTERN US BUCKLES TODAY
ALLOWING AN INCREASED CHANCE FOR SHOWERS AND STORMS. THE CHANCE
MOVES INTO THE SBN BY AROUND 20 OR 21Z AND CLOSER TO 22Z OR 23Z AT
FWA SO WILL HAVE SOME MVFR CONDITIONS TO ACCOUNT FOR THAT, BUT THERE
COULD ALSO BE SOME IFR CONDITIONS DUE TO THE HEAVY RAIN POTENTIAL. A
PERIOD OF SUSTAINED WINDS REACHING 10 TO 12 KTS OCCURS THIS
AFTERNOON BEFORE RELAXING THIS EVENING. STRONGER STORMS SHOULD BE
OUT OF THE AREA BY AROUND 3Z. HOWEVER, MORE STORMS THAT COULD
STILL BE STRONG MAY RE-ENTER/REFORM THERE NOT TOO LONG
AFTERWARDS AS ANOTHER DISTURBANCE MOVES INTO THE AREA. WILL ALSO
HANDLE THIS CHANCE WITH ANOTHER PROB30 GROUP.
IWX WATCHES/WARNINGS/ADVISORIES
IN...HEAT ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR
INZ005>008-012>015-020-103-104-116-203-204-216.
EXTREME HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR INZ009-
017-018-022>027-032>034.
HEAT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT SATURDAY FOR
INZ009-017-018-022>027-032>034.
OH...EXTREME HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR OHZ001-
002-004-005-015-016-024-025.
HEAT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT SATURDAY FOR
OHZ001-002-004-005-015-016-024-025.
MI...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ078>081-177-
277.
MARINE...NONE.
DISCUSSION...JOHNSON
AVIATION...ROLLER
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