533
FXUS63 KIWX 170832
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
432 AM EDT FRI JUL 17 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 402 AM EDT FRI JUL 17 2026
A QUASI-STATIONARY/COOL FRONTAL BOUNDARY IS CURRENTLY DRAPED
FROM THE NORTHWEST TO THE SOUTHEAST JUST SOUTH OF OUR CWA. THIS
BOUNDARY HELPED TO KICK OFF A COUPLE OF ISOLATED INSTABILITY
THUNDERSTORMS LAST EVENING THAT WERE NEARLY STATIONARY AND
PRODUCED HEAVY DOWNPOURS WITH PWS OF 1.5 TO 1.75 INCHES OVER
THE AREA. FORECASTED PWS LATER TODAY AND ON SATURDAY PUSH
CLOSER TO 2 INCHES WITH INCREASED SOUTHERLY FLOW AND A BIT OF
MOISTURE ADVECTION AS SURFACE DEW POINTS INCREASE BACK INTO THE
70S ON SATURDAY. SHEAR VALUES TODAY WILL TOP OUT AROUND 25 KTS
WHILE ON SATURDAY VALUES ABOUT DOUBLE TO AROUND 50 KTS. DCAPES
VALUES TODAY WILL TOP OUT AROUND 2000 J/KG WHILE TOMORROW VALUES
INCREASE TO AROUND 3000 J/KG. TODAY SPC HAS A MARGINAL RISK OF
SEVERE STORMS OVER OUR SOUTHEASTERN PORTIONS OF THE AREA WITH
THE BOUNDARY STILL IN THE VICINITY. HOWEVER, TOMORROW BETTER
SYNOPTIC FORCING ARRIVES WITH A SHORTWAVE PUSHING INTO THE AREA
WITH AN ACCOMPANYING COLD FRONT AND THIS WILL ALL LEAD TO THE
POTENTIAL OF STRONGER STORMS. SPC CURRENTLY HAS OUR AREA WITH
MARGINAL TO SLIGHT RISKS FOR SEVERE STORMS. THE MAIN THREATS
LOOK TO BE GUSTY OUTFLOW WINDS AND HEAVY DOWNPOURS THAT CAN LEAD
TO LOCALIZED NUISANCE FLOODING ESPECIALLY TODAY WITH STEERING
FLOW ON THE WEAK SIDE.
SMOKE AND POOR AIR QUALITY CONTINUE TODAY BUT SHOULD SEE A BIT
MORE IMPROVEMENT LATER TODAY AS THE FLOW INCREASES ALOFT AHEAD
OF THE INCOMING SHORTWAVE. HEAT AND HUMIDITY ALSO CONTINUES
TODAY AND SATURDAY WITH HIGHS IN THE UPPER 80S TO LOW 90S. IN
THE WAKE OF THE COLD FRONT SUNDAY AND MONDAY WILL SEE A BREAK
IN THE HEAT AND HUMIDITY WITH HIGHS IN THE LOWER 80S EACH DAY
AND DRIER DEW POINTS RANGING IN THE UPPER 50S TO LOWER 60S. A
BREAK IN PRECIPITATION WILL ALSO TAKE PLACE SUNDAY THROUGH THE
MOST OF THE DAY MONDAY BEFORE ANOTHER TROUGH AND COLD FRONT DROPS
INTO THE REGION ON MONDAY EVENING INTO TUESDAY BRINGING ANOTHER
BATCH OF SHOWERS AND THUNDERSTORMS AS WELL AS EVEN COOLER
TEMPERATURES ARRIVE FOR THE MIDDLE OF NEXT WEEK WITH HIGHS ONLY
IN THE 70S ON WEDNESDAY AND THURSDAY.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 129 AM EDT FRI JUL 17 2026
SMOKE/HAZE CONTINUES TO REDUCE VSBYS AT THE SURFACE AS LOW AS 1
MILE. IFR VISIBILITIES CONTINUE AT KSBN AND MVFR VISIBILITIES
AT KFWA OVERNIGHT. WINDS 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 MVFR CIGS AND VSBYS IN
THE HEAVIER DOWNPOURS AT BOTH TERMINALS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...AIR QUALITY ALERT UNTIL MIDNIGHT EDT /11 PM CDT/ TONIGHT FOR
INZ005>009-012>015-017-018-020-022>027-032>034-104-116-
204-216.
AIR QUALITY ALERT UNTIL MIDNIGHT CDT TONIGHT FOR INZ103-203.
OH...AIR QUALITY ALERT UNTIL MIDNIGHT EDT TONIGHT FOR OHZ001-002-
004-005-015-016-024-025.
MI...AIR QUALITY ALERT UNTIL MIDNIGHT EDT TONIGHT FOR MIZ078>081-
177-277.
MARINE...DENSE SMOKE ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ043-
046.
DISCUSSION...ANDERSEN
AVIATION...ANDERSEN
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