514
FXUS63 KIWX 131035
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
635 AM EDT THU AUG 13 2026
KEY MESSAGES
- AREAS OF FOG ARE EXPECTED THIS MORNING AND MAY BE DENSE IN
SPOTS.
- THERE IS A 30-50% CHANCE OF STORMS LATE THIS AFTERNOON BUT
SEVERE WEATHER IS NOT EXPECTED.
- MORE WIDESPREAD, HEAVY RAIN IS POSSIBLE LATE TONIGHT INTO
EARLY FRIDAY MORNING, ESPECIALLY SOUTH OF US-30 WHERE A LOT OF
RAIN HAS ALREADY FALLEN. A FLOOD WATCH REMAINS IN EFFECT THERE
THROUGH FRIDAY MORNING.
- MORE STORMS ARE POSSIBLE OVER THE WEEKEND BUT THE POTENTIAL
FOR HEAVY RAIN AND FLOODING WILL BE LOWER.
DISCUSSION
ISSUED AT 140 AM EDT THU AUG 13 2026
A WELCOME (EVEN IF BRIEF) RESPITE FROM RAIN THIS MORNING. MAIN
CONCERN IN THE IMMEDIATE NEAR TERM IS POTENTIAL FOR SOME FOG
AGAIN THIS MORNING GIVEN LIGHT WINDS AND AMPLE NEAR-SURFACE
MOISTURE. COMPLICATING FACTOR THIS MORNING IS LARGE AREA OF
STRATUS THAT DEVELOPED EARLIER. THIS STRATUS IS DISSIPATING BUT
GUIDANCE STRUGGLED TO CAPTURE THIS AND SUBSEQUENTLY THE MODELED
WIDESPREAD, DENSE FOG IS VERY MUCH IN QUESTION. WILL CONTINUE TO
MONITOR CLOSELY THROUGH THE MORNING BUT NOT SEEING ENOUGH
SIGNALS TO WARRANT A DENSE FOG ADVISORY JUST YET.
UNFORTUNATELY, CHANCES FOR RAIN RETURN QUICKLY LATER TODAY AND
ESPECIALLY TONIGHT AS WE REMAIN IN THE "RING OF FIRE." THE FIRST
FEATURE OF INTEREST IS AN MCV ASSOCIATED WITH CONVECTION PRESENTLY
OVER NE/SD. THE FEATURE WILL TRACK INTO OUR CWA DURING THE LATE
AFTERNOON WITH OUR NEXT CHANCE OF RAIN. HOWEVER, WE CONTINUE TO SEE
A STEP DOWNWARD IN MIDLEVEL LAPSE RATES, LOW LEVEL THETA-E
ADVECTION, AND SUBSEQUENT INSTABILITY (MUCH LIKE YESTERDAY WAS A STEP
DOWN FROM THE DAY BEFORE). THE LLJ IS MUCH WEAKER THIS MORNING
(EVIDENCED BY NEAR TOTAL LACK OF CONVECTION IN OUR REGION) AND
SURFACE OBS/MESOANALYSIS SUGGEST YESTERDAY'S ACTIVITY NUDGED THE
FRONT SLIGHTLY FURTHER SOUTH. EVEN SEEING SOME N/NE FLOW AT 850MB
INTO OUR NORTHERN CWA. ALL OF THIS TO SAY THAT THE AFTERNOON
ACTIVITY IS EXPECTED TO REMAIN WEAK AS IT ENTERS OUR CWA. SOME
GUSTY WINDS CAN'T BE ENTIRELY RULED OUT THOUGH, AS WELL AS SOME
BRIEF HEAVY RAIN IN AN AREA THAT REALLY CAN'T TAKE ANYMORE.
THE FAR GREATER CONCERN WILL BE WHAT HAPPENS LATE TONIGHT/EARLY FRI.
ANOTHER SHORTWAVE EJECTS INTO THE CENTRAL PLAINS AND ONCE AGAIN
STRENGTHENS THE DOWNSTREAM LLJ. ANOTHER ROUND OF STRONG LOW LEVEL
THETA-E ADVECTION IS ANTICIPATED, THOUGH THERE IS STILL SOME SPREAD
REGARDING JUST HOW STRONG BETWEEN THE NAM AND OTHER HI-RES GUIDANCE
VS. LOWER-RES GLOBAL MODELS. REGARDLESS OF THE DETAILS, THE STAGE IS
SET FOR ANOTHER ROUND OF VERY HEAVY RAIN ROUGHLY 04-12Z FRI MORNING.
THE EXACT PLACEMENT REMAINS SOMEWHAT UNCERTAIN THIS FAR OUT BUT A
CONCENSUS BLEND WOULD PUT THE HIGHEST PROBABILITIES SQUARELY OVER
THE SAME AREA ALREADY HIT HARD IN OUR FAR SOUTHERN CWA AND
IND'S N/NE CWA. OUR FLOOD WATCH WAS ALREADY EXTENDED THROUGH FRI
MORNING GIVEN THIS POTENTIAL AND HIGH SENSITIVITY TO ANY RAIN
SOUTH OF US-30. AN ARGUMENT COULD BE MADE TO REMOVE THE TIER OF
COUNTIES RIGHT ALONG US-30 BUT CONFIDENCE IS TOO LOW TO GET
THAT SURGICAL AT THIS POINT.
THERE IS SOME LIGHT AT THE END OF THIS TUNNEL THOUGH. THE
EASTERN CANADA UPPER LOW KEEPING OUR REGION ON THE NORTHEAST
FRINGE OF THIS RIDGE FINALLY RELEASES EASTWARD ALLOWING THE
RIDGE (AND ASSOCIATED STORM TRACK) TO (TEMPORARILY) LIFT
NORTHWARD. STORMS REMAIN IN THE FORECAST FOR SAT BUT SHOULD BE
MUCH MORE PROGRESSIVE AND FOCUSED MORE IN OUR NORTHERN CWA VS.
SOUTH. THE RIDGE THEN BREAKS DOWN COMPLETELY BY LATE SUNDAY AS A
COLD FRONT CROSSES THE AREA. HERE AGAIN, SOME STORMS POSSIBLE
BUT WEAKER, MORE PROGRESSIVE AND OVERALL JUST A DIFFERENT SETUP
THAT IS LESS CONDUCIVE FOR HEAVY RAIN. COOL AND DRY CONDITIONS
THEN EXPECTED MON THROUGH AT LEAST EARLY WED.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 635 AM EDT THU AUG 13 2026
AREA OF STRATUS CURRENTLY OVER THE TERMINALS IS PREVENTING FOG
DEVELOPMENT BUT CEILINGS MAY STILL BE IFR OVER THE NEXT 2-3
HOURS BEFORE SLOWLY LIFTING THROUGH LATE MORNING. RETURN TO VFR
ANTICIPATED BY AFTERNOON BUT ANOTHER ROUND OF STORMS IS
POSSIBLE THIS EVENING AND OVERNIGHT, ESPECIALLY AT KFWA.
CONFIDENCE REMAINS LOW REGARDING THE EXACT TIMING AND COVERAGE
THOUGH.
IWX WATCHES/WARNINGS/ADVISORIES
IN...FLOOD WATCH THROUGH FRIDAY MORNING FOR INZ012>015-017-018-020-
022>027-032>034-116-203-216.
OH...FLOOD WATCH THROUGH FRIDAY MORNING FOR OHZ024-025.
MI...NONE.
MARINE...NONE.
DISCUSSION...AGD
AVIATION...AGD
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