711
FXUS61 KILN 111049
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
649 AM EDT TUE AUG 11 2026
WHAT HAS CHANGED
DUE TO THE HIGHER POTENTIAL FOR IMPACTS, THE DAMAGING WIND AND FLASH
FLOOD THREAT HAVE BEEN SEPARATED INTO SECTIONS.
KEY MESSAGES
1) INCREASED THREAT FOR A SIGNIFICANT DAMAGING WIND EVENT ACROSS THE
AREA THIS AFTERNOON AND EVENING.
2) INCREASED THREAT FOR FLASH FLOODING ACROSS THE AREA TODAY THROUGH
WEDNESDAY MORNING.
3) ADDITIONAL CHANCES FOR THUNDERSTORMS AND HEAVY RAIN ARE POSSIBLE
THROUGH THE END OF THE WEEK WITH DRIER WEATHER ATTEMPTING TO RETURN
LATE FRIDAY AND INTO THE WEEKEND.
DISCUSSION
MORNING UPDATE...
LATEST SATELLITE DATA SHOWS AN EXPANSIVE AREA OF COOLING CLOUD TOPS
ACROSS NORTHERN INDIANA AS ROBUST THUNDERSTORMS DEVELOP. THIS IS THE
SECOND FEATURE NOTED BELOW. THE EVOLUTION OF THIS FEATURE AHEAD OF
THE MAIN LINE WILL PLAY AN IMPORTANT ROLE IN THE HIGHER-END SCENARIO
FOR TODAY. IF THIS COMPLEX SURVIVES INTO THE LOCAL AREA, THIS WOULD
NUDGE THE HIGHER WIND THREAT FARTHER SOUTH. WHEREVER THE NORTHERN
BOUNDARY OF THE HIGHEST INSTABILITY RESIDES, THAT WILL BE THE
NORTHERN EXTENT OF THE MORE SIGNIFICANT WIND THREAT. MORE
SPECIFICALLY, THIS WOULD DECREASE THE POTENTIAL FOR THE SIGNIFICANT
WINDS LATER TODAY FOR LOCATIONS LIKE WEST-CENTRAL OHIO INTO CENTRAL
AND SOUTH- CENTRAL OHIO. DEPENDING ON HOW FAR SOUTH IT ADVANCES, THE
THREAT COULD BE LIMITED TO SOUTHEAST INDIANA, SOUTHWEST OHIO, AND
PORTIONS OF NORTHERN KENTUCKY. CHECK FOR UPDATES THROUGHOUT THE DAY!
PREVIOUS DISCUSSION (3:29 AM)...
KEY MESSAGE 1) NOW THAT THE LATE EVENING AND EARLY OVERNIGHT
THUNDERSTORM COMPLEX HAS SHIFTED SOUTHEAST OF THE REGION, THE
NORTHERN HALF OF THE AREA IS CURRENTLY IN A STABLE COLD POOL AIR
MASS, WHILE THE SOUTHERN HALF IS STILL CONSIDERABLE UNSTABLE.
THUNDERSTORMS ARE BEGINNING TO FORM ALONG A STALLED BOUNDARY
CURRENTLY PLACED ACROSS NORTHERN INDIANA. IF THESE THUNDERSTORMS
ATTEMPT TO MOVE SOUTHEAST, THEY WILL ENCOUNTER THE COLD POOL AIR MASS
PREVIOUSLY MENTIONED. THESE STORMS WOULD STRUGGLE TO ORGANIZE AS A
RESULT. TRENDS WILL BE MONITORED OVER THE NEXT FEW HOURS, BUT THIS IS
FIRST FEATURE WHICH COULD PLAY AN IMPORTANT ROLE IN TODAY'S
SIGNIFICANT WIND THREAT POTENTIAL.
THE SECOND FEATURE IS ACROSS SOUTHERN WISCONSIN AND NORTHERN
ILLINOIS. NEAR THE NORTHERN TIP OF THE LOW-LEVEL JET, THUNDERSTORMS
ARE BEGINNING TO DEVELOP. TO THE EAST AND SOUTH OF THESE STORMS,
UNDISTURBED ENERGY REMAINS. WHILE THIS IS AHEAD OF THE BETTER FORCING
ASSOCIATED WITH THE SHORTWAVE, THE AVAILABLE ENERGY TO THE SOUTH
WOULD GIVE IT A MUCH BETTER CHANCE TO EVOLVE INTO A MORE ORGANIZED
STORM COMPLEX INTO THE MORNING HOURS.
IF THESE TWO FEATURES REMAIN ON THE WEAKER SIDE, CONFIDENCE WOULD
BECOME VERY HIGH THAT THE LOCAL AREA WOULD SEE A WIDESPREAD,
SIGNIFICANT DAMAGING WIND EVENT LATER THIS AFTERNOON AND EVENING. THE
SECOND FEATURE HAS THE BETTER CHANCE OF ORGANIZING, THEREFORE IT
WOULD LIKELY HAVE THE BIGGEST ROLE TO PLAY IN ALTERING LOCAL IMPACTS
FROM THE HIGHER-END SCENARIO. THERE IS ALSO THE POTENTIAL WHERE THIS
FEATURE AND THE MAIN EVENT COMBINE AS THEY APPROACH THE LOCAL AREA.
AS SPC NOTES IN THEIR DISCUSSION, ALL ENVIRONMENTAL PARAMETERS ARE
IN PLACE FOR A WIDESPREAD, POTENTIALLY SIGNIFICANT DAMAGING WIND
EVENT ACROSS THE AREA. THE TIMING IS ALSO OPTIMAL FOR THE LOCAL AREA,
MOVING THROUGH DURING THE PEAK OF THE DIURNAL INSTABILITY (AFTERNOON
INTO EVENING). DAMAGING WIND GUSTS OF 75+ MPH ARE LIKELY IF A WELL-
ORGANIZED MCS CAN DEVELOP AND THEN MOVE THROUGH THE AREA. THE MAJOR
LIMITING FACTOR WOULD BE ANY EARLIER DEVELOPMENT AHEAD OF THIS MAIN
EVENT. DESPITE THE FOCUS BEING ON THE MORE WIDESPREAD DAMAGING WIND
EVENT, EMBEDDED TORNADOES WITHIN THE SQUALL-LINE WOULD ALSO BE
POSSIBLE, ESPECIALLY ON THE NORTHERN SEGMENT OF THE MCS. LARGE HAIL
COULD ALSO OCCUR IN THE DEEPEST THUNDERSTORMS.
KEY MESSAGE 2)
MORNING UPDATE...FLASH FLOOD WATCH EXPANDED FOR THE ENTIRE AREA.
PREVIOUS DISCUSSION (3:29 AM)...
THE BEST CHANCE FOR FLASH FLOODING ACROSS THE NORTHERN PORTION OF
THE AREA WOULD BE IF MULTIPLE ROUNDS OF THUNDERSTORMS OCCUR LATER
THIS MORNING AND THROUGH THE AFTERNOON. THEN, IF AN ORGANIZED MCS
MOVES THROUGH, MULTIPLE INCHES WOULD HAVE ACCUMULATED OVER THIS
REGION.
OF MORE INCREASING CONCERN, AFTER THE MCS MOVES THROUGH, MOISTURE
WILL CONTINUE TO MOVE INTO THE REGION FROM THE SOUTHWEST. BACK
BUILDING OF THUNDERSTORMS ALONG THE STRETCHED OUTFLOW WILL FOCUS A
FLASH FLOOD THREAT OVER A PORTION OF THE AREA. THIS ACTIVITY COULD
CONTINUE WELL INTO WEDNESDAY AS THE FRONT STALLS OVER SOUTHERN
PORTIONS OF THE AREA. SPC HREF LPMM DOES SUPPORT THIS POTENTIAL OVER
SOUTH-CENTRAL AND SOUTHERN OHIO, BUT THERE IS A GROWING SIGNAL FOR
SOUTHEAST INDIANA, SOUTHWEST OHIO AND NORTHERN KENTUCKY (SOME OF
THESE COUNTIES ARE OUTSIDE THE FLOOD WATCH). BECAUSE THIS THREAT MAY
NOT EVOLVE UNTIL LATER TONIGHT AND INTO WEDNESDAY, THE FLOOD WATCH
HAS NOT BEEN EXTENDED TO INCLUDE THESE AREAS QUITE YET. HOWEVER, IT
MAY BE NEEDED LATER TODAY AS CONFIDENCE INCREASES. IF A BACK-BUILDING
SCENARIO CAN DEVELOP, LOCALIZED AMOUNTS OF 5-7" ARE PLAUSIBLE AS SEEN
FROM EARLIER EVENTS IN PERRY COUNTY OH THIS EVENING.
KEY MESSAGE 3)
THURSDAY AND THROUGH THE WEEKEND, LONG-RANGE GUIDANCE CONTINUES TO
SUGGEST AN ACTIVE PATTERN WILL CONTINUE OVER THE OHIO VALLEY, BUT
SOME BREAKS ARE POSSIBLE. THIS IS LARGELY DUE TO A RIDGE OF HIGH
PRESSURE OVER THE MIDDLE AND LOWER MISSISSIPPI RIVER VALLEY FEEDING
MOISTURE NORTHWARD. THE TROUGH OVER SOUTHEAST CANADA IS SUPPLYING A
STEADY AMOUNT OF NORTHWESTERLY UPPER LEVEL FLOW, INCREASING WIND
SHEAR OVER THE REGION. THERE ARE SIGNS THIS MAY BREAKDOWN AS THE
RIDGE BUILDS NORTHWARD OVER THE UPPER MIDWEST INTO THE WEEKEND. THIS
WOULD BRING A SURGE OF LOWER PWATS SOUTHWARD REDUCING RAINFALL
CHANCES FRIDAY INTO SATURDAY. CHANCES FOR THUNDERSTORMS INCREASE TO
ROUND OUT THE WEEKEND.
AVIATION /12Z TUESDAY THROUGH SATURDAY/
A NEW ROUND OF THUNDERSTORMS IS BEGINNING TO FORM ACROSS NORTHERN
INDIANA. THIS WILL LIKELY PROGRESS SOUTHEASTWARD INTO AREA TAF SITES
BETWEEN 13Z AND 16Z. THIS COULD BE THE FIRST OF SEVERAL ROUNDS OF
THUNDERSTORMS TODAY. IF CONDITIONS ALLOW, THERE IS THE POTENTIAL
FOR A LINE OF SIGNIFICANT WINDS GUSTS (75+ MPH) THIS AFTERNOON AND
EVENING. BECAUSE THERE THIS THREAT FOR EARLIER ROUNDS OF
THUNDERSTORMS, PROB30 GROUPS BEGIN LATE THIS MORNING AND INTO THE
EARLY AFTERNOON. BECAUSE OF THE HIGHER CONFIDENCE LATE THIS AFTERNOON
AND EVENING, TEMPO GROUPS HAVE BEEN ADDED. EXPECT TIMING ADJUSTMENTS
THROUGHOUT THE DAY.
OTHERWISE WINDS ARE OUT OF THE SOUTHWEST AROUND 10 KNOTS BEFORE
THUNDERSTORM ACTIVITY POTENTIALLY INFLUENCES THEM. WINDS BECOME MORE
WESTERLY AFTER 00Z AS A FRONT SLIDES THROUGH THE AREA.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE AT TIMES THROUGH FRIDAY.
ILN WATCHES/WARNINGS/ADVISORIES
OH...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR OHZ026-034-035-042>046-
051>056-060>065-070>074-077>082-088.
KY...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR KYZ089>100.
IN...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR INZ050-058-059-066-
073>075-080.
DISCUSSION...MCGINNIS
AVIATION...MCGINNIS
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