926
FXUS61 KILN 040609
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
209 AM EDT FRI SEP 4 2026
WHAT HAS CHANGED
HEAT ADVISORY EXPANDED FARTHER NORTH ON FRIDAY.
KEY MESSAGES
1) HEAT HEADLINES CONTINUE THROUGH FRIDAY AFTERNOON FOR MUCH OF THE
REGION. HOT AND MUGGY CONDITIONS CONTINUE AGAIN ON SATURDAY, THOUGH
WILL LIKELY FALL BELOW HEADLINE CRITERIA.
2) STRONG TO SEVERE STORMS WILL BE POSSIBLE AT TIMES TODAY AND
SATURDAY. ANY STORMS THAT DEVELOP MAY PRODUCE LOCALLY HEAVY RAINFALL.
DISCUSSION
KEY MESSAGE 1)
500H RIDGE OVER THE TENNESSEE VALLEY REGION WILL CONTINUE TO PROVIDE
MASS SUBSIDENCE AND HOT CONDITIONS ACROSS THE AREA. FRESH GUIDANCE
PAINTS HEAT INDICES AROUND 100F FOR MOST AREAS ALONG AND SOUTH OF THE
I-70 CORRIDOR ON FRIDAY AFTERNOON. ADDITIONALLY, GUIDANCE CAME IN A
TAD WARMER FOR AREAS ALONG THE OH/IN BORDER, SO HAVE EXPANDED THE
HEAT HEADLINE ACCORDINGLY. THE RIDGE WILL CONTINUE TO BE SQUASHED BY
A TROUGH MOVING THROUGH EASTERN CANADA, RESULTING IN SLIGHTLY COOLER
TEMPERATURES ACROSS CENTRAL AND EASTERN OHIO.
THERE IS SOME QUESTION AS TO WHETHER AN EXTENSION TO THE HEAT
ADVISORY WILL NEED TO BE MADE FOR PORTIONS OF THE TRI-STATE FOR
SATURDAY. HOWEVER, DECIDED TO HOLD OFF FOR NOW GIVEN UNCERTAINTY WITH
STORMS AND CLOUD BLOWOFF (SEE MORE BELOW).
KEY MESSAGE 2)
AS WE HEAD THROUGH THE DAYTIME HOURS ON FRIDAY, THE DISTURBANCE IN
CANADA BEGINS TO DEEPEN AND STRONGER NORTHWESTERLY FLOW BEGINS TO
ENCROACH INTO THE AREA. THIS SHIFT PUTS US MORESO INTO MCS TERRITORY
IN TERMS OF SHEAR AND DRIVING FLOW. OF COURSE, TIMING OUT MCS ARRIVAL
IS NOTORIOUSLY DIFFICULT AND OFTEN DEPENDS ON PREVIOUS MCS
DEVELOPMENT/DECAY AND RESIDUAL OUTFLOW BOUNDARIES.
HANDFUL OF CAMS PULL A COMPLEX THROUGH CENTRAL OHIO THROUGH FRIDAY
AFTERNOON WHILE OTHERS KEEP US ENTIRELY DRY. IN ADDITION TO THAT
AMBIGUITY, THERE ALSO ISN'T A STRONG CONSENSUS BETWEEN RUN TO RUN OF
VARIOUS CAMS EITHER. AS SUCH, ONCE AGAIN, WE HAVE A LOW CONFIDENCE
FORECAST. HOWEVER, IF WE DO END UP WITH AFTERNOON THUNDERSTORM
DEVELOPMENT, SBCAPE ON THE ORDER OF 2500 J/KG, STEEP LL LAPSE RATES,
SPLOTCHY BULK SHEAR AROUND 30-35 KNOTS, AND PWATS AROUND 180% OF
NORMAL INTRODUCE A SEVERE WIND AND LOCALLY HEAVY RAINFALL THREAT.
GREATEST CONFIDENCE IN THIS OCCURRING IS ONCE AGAIN THROUGH CENTRAL
OHIO
DEPENDING ON THE ACTIVITY FRIDAY, ANOTHER ROUND OR TWO OF STORMS
WOULD BE POSSIBLE FRIDAY NIGHT INTO SATURDAY MORNING WITH ADDITIONAL
SHORTWAVE IMPULSES ROUNDING THE BASE OF THE LARGER FLOW. AS NOTED IN
PREVIOUS DISCUSSIONS, MULTIPLE THUNDERSTORM COMPLEXES ARE POSSIBLE
ACROSS THE LOCAL AREA UP UNTIL SATURDAY EVENING. DRIER AIR WILL
EVENTUALLY WORK INTO THE REGION FROM THE NORTH AS THE RIDGE GETS
SUPPRESSED TO THE WEST.
WITH PWATS WELL ABOVE NORMAL, MULTIPLE THUNDERSTORM COMPLEXES WILL
PROVIDE THE OPPORTUNITY FOR LOCALLY HEAVY RAINFALL AND FLASH
FLOODING, ESPECIALLY FOR AREAS WHERE STORMS MOVE OVER REPEATEDLY.
AVIATION /06Z FRIDAY THROUGH TUESDAY/
QUIET CONDITIONS EXPECTED OVERNIGHT WITH PATCHY RIVER VALLEY FOG;
HAVE DROPPED LUK ACCORDINGLY. NEARLY CALM WINDS OVERNIGHT WILL PICK
UP ON FRIDAY, BECOMING WESTERLY AROUND 5-10 KNOTS. A SCATTERED CU
FIELD SHOULD DEVELOP BY THE AFTERNOON HOURS AS WE BEGIN TO MIX.
THICKER CLOUDS WILL EXIST MORESO ACROSS CENTRAL OHIO INTO
NORTHEASTERN OHIO.
PM THUNDERSTORMS ARE POSSIBLE ACROSS THE REGION, WITH HIGHER CHANCES
THROUGH CENTRAL OH (LCK, CMH). HAVE ADDED PROB30S, THOUGH CONFIDENCE
ON STORM TIMING/PLACEMENT IS LOW. WILL LIKELY END UP NEEDING TO TWEAK
TIMING AND POTENTIALLY ADD PROB30S FOR STORMS INTO DAY AND ILN, BUT
WILL HOLD OFF ON ADDING AT THE MOMENT.
WINDS DECREASE AGAIN OVERNIGHT FRIDAY INTO SATURDAY.
OUTLOOK...THUNDERSTORMS POSSIBLE AT TIMES ON FRIDAY THROUGH SATURDAY.
ILN WATCHES/WARNINGS/ADVISORIES
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ042-051-053>055-
060>065-070>074-077>082-088.
KY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR KYZ089>100.
IN...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR INZ050-058-059-066-
073>075-080.
DISCUSSION...AIENA
AVIATION...AIENA
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