803
FXUS63 KIWX 162322
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
722 PM EDT THU JUL 16 2026
KEY MESSAGES
- AIR QUALITY ALERTS CONTINUE TODAY AND INTO FRIDAY, IN PART
DUE TO SMOKY CONDITIONS.
- INCREASING CHANCE (30% TO 70%) FOR SHOWERS AND THUNDERSTORMS
BY FRIDAY AFTERNOON. STORMS MAY PRODUCE HEAVY RAIN.
- THUNDERSTORMS ON SATURDAY AFTERNOON MAY PRODUCE DAMAGING WIND
GUSTS.
- NOT AS WARM STARTING SUNDAY.
DISCUSSION
ISSUED AT 204 PM EDT THU JUL 16 2026
SURFACE HIGH PRESSURE BENEATH A SUBTLE SAG IN NORTHWESTERLY FLOW
ALOFT HAS USHERED IN PLENTY OF WILDFIRE SMOKE OVER OUR AREA. BASED
ON SURFACE VISIBILITY OBSERVATIONS, NEAR-SURFACE SMOKE HAS BEEN MOST
PREVALENT NORTH OF US 30, ESPECIALLY ALONG THE SOUTHERN MICHIGAN
STATE LINE. THERE, VISIBILITY HAS BEEN BELOW 2 MILES MOST OF
TODAY, WITH INSTANCES OF 1 MILE VISIBILITY. THIS HAS ALSO
NOTABLY LIMITED TEMPERATURES TODAY. WITHIN THE HEAT ADVISORY,
SOME UPPER-80S ARE NOTED WITH HEAT INDICIES IN THE MID-90S. AS
WE APPROACH PEAK- HEATING, WE'LL KEEP THE (MARGINAL) HEAT
ADVISORY IN PLACE FOR NOW. AVAILABLE FORECAST GUIDANCE
INDICATES THESE SMOKY CONDITIONS MAY SPREAD FURTHER SOUTH
TONIGHT AND REMAIN IN PLACE AFTER SUNRISE FRIDAY. HOWEVER,
CONDITIONS MAY IMPROVE AS THE DAY PROGRESSES AS SURFACE HIGH
PRESSURE DRIFTS EAST IN RESPONSE TO AN INCOMING UPPER GREAT
LAKES TROUGH AND AN ADVANCING WARM FRONT.
LOOK FOR INCREASING COVERAGE OF SHOWERS AND THUNDERSTORMS TOMORROW
AFTERNOON AS A WARM FRONT ADVANCES FROM THE SOUTHWEST. SHEAR WILL BE
INCREDIBLY LIMITED (LESS THAN 20 KNOTS) KEEPING THE SEVERE
WEATHER RISK IN CHECK. IN CONTRAST, DUE TO AN OVERALL ABSENCE
OF UPPER-LEVEL FLOW, SLOW-MOVING STORMS MAY PRODUCE HEAVY
RAINFALL AS PWATS PUSH 2 INCHES BY THE AFTERNOON.
A MARGINAL TO SLIGHT RISK OF SEVERE STORMS IS HIGHLIGHTED BY THE
STORM PREDICTION CENTER FOR SATURDAY. A WELL-ORGANIZED UPPER-
LEVEL LOW SWEEPS THROUGH WISCONSIN AND MICHIGAN AMID AN
ENVIRONMENT WITH PLENTY OF INSTABILITY (>1,500 J/KG) AND ONLY
MARGINAL SHEAR SHY OF 30 KNOTS. GUIDANCE GENERALLY SUGGESTS
DISCRETE STORMS ALONG A COLD FRONT MAY MATURE INTO LINEAR
SEGMENTS, POSING A RISK FOR DAMAGING WIND GUSTS.
HIGH PRESSURE BRIEFLY SETTLES IN SUNDAY AND MONDAY BRINGING COOLER
AND LESS HUMID CONDITIONS. ENERGETIC NORTHWEST FLOW SPILLS OVER THE
GREAT LAKES BY MIDWEEK PRESENTING RENEWED CHANCES FOR WET WEATHER
WHILE KEEPING AFTERNOON HIGH TEMPERATURES NEAR-NORMAL (MID-80S)
OR JUST A FEW DEGREES SHY OF NORMAL.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 719 PM EDT THU JUL 16 2026
VISIBLE SATELLITE IMAGERY SHOWS SMOKE CONTINUING TO BLANKET OUR
FORECAST AREA, ESPECIALLY ALONG AND NORTH OF US 30. THE SMOKE IS
REDUCING VISIBILITIES AT THE SURFACE AS LOW AS 1 MILE. EXPECT
IFR VISIBILITIES TO CONTINUE AT KSBN AND MVFR VISIBILITIES AT
KFWA OVERNIGHT. WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT,
THEN INCREASE TO AROUND 5 TO 10 KTS OUT OF THE SOUTH TOMORROW.
SMOKE IS EXPECTED TO DISPERSE BY TOMORROW AFTERNOON AS WINDS
BECOME SOUTHWEST/WEST AND RAIN/STORM CHANCES INCREASE. AFTER
18Z FRIDAY, SCATTERED SHOWERS AND STORMS, WITH POTENTIAL FOR
MVFR CEILINGS AND VISIBILITIES, ARE EXPECTED AT BOTH TERMINALS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...AIR QUALITY ALERT UNTIL MIDNIGHT EDT /11 PM CDT/ FRIDAY NIGHT
FOR INZ005>009-012>015-017-018-022>027-032>034-104-116-
204-216.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR INZ013-015-020-
022>027-032>034.
AIR QUALITY ALERT FROM MIDNIGHT TONIGHT TO MIDNIGHT EDT FRIDAY
NIGHT FOR INZ020.
AIR QUALITY ALERT UNTIL MIDNIGHT CDT FRIDAY NIGHT FOR INZ103-
203.
OH...AIR QUALITY ALERT UNTIL MIDNIGHT EDT FRIDAY NIGHT FOR OHZ001-
002-004-005-015-016-024-025.
MI...AIR QUALITY ALERT UNTIL MIDNIGHT EDT FRIDAY NIGHT FOR
MIZ078>081-177-277.
MARINE...DENSE SMOKE ADVISORY UNTIL 8 PM EDT FRIDAY FOR LMZ043-046.
DISCUSSION...JOHNSON
AVIATION...MARSILI
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