456
FXUS61 KILN 131759
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
159 PM EDT TUE MAY 13 2025
SYNOPSIS
AN UPPER LEVEL LOW WILL CONTINUE MOVING NORTHEAST THROUGH THE REGION
TODAY AND TOMORROW, BRINGING OCCASIONAL SHOWERS AND STORMS. WARMER
CONDITIONS ARE EXPECTED FOR THE END OF THE WEEK, AFTER THE LOW MOVES
OUT OF THE AREA. THERE WILL BE ADDITIONAL CHANCES FOR SHOWERS AND
STORMS, BEGINNING THURSDAY NIGHT.
NEAR TERM /UNTIL 6 PM THIS EVENING/
NO SIGNIFICANT CHANGES MADE WITH THE MORNING UPDATE. LOW CLOUDS WILL
LIKELY LIMIT HIGH TEMPERATURES TODAY, SO HAVE CONTINUED TO SHAVE A
DEGREE OR TWO OFF THE NATIONAL BLEND'S SOLUTION. LATEST HRRR
CONTINUES TO SHOW DEVELOPMENT OF SHOWERS AND STORMS THIS AFTERNOON...
WITH GENERAL MOVEMENT TOWARD THE NORTHWEST. A VERY MOIST COLUMN LEADS
TO SBCAPE AROUND 1000J/KG DESPITE MEAGER SURFACE HEATING, WITH THE
SOUNDING LEANING IN THE DIRECTION OF A HEAVY RAIN THREAT VS. ANY
SEVERE WEATHER THREAT. WILL NEED TO MONITOR LOCALIZED FLOOD POTENTIAL
BASED ON BACK-BUILDING STORMS OR REPEATED ROUNDS OVER ANY SINGLE
LOCATION.
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/
THE OVERNIGHT HOURS HEADING INTO WEDNESDAY MORNING ARE LIKELY TO BE
MOSTLY DRY, THOUGH SOME SCATTERED SHOWERS UNDER THE UPPER LOW COULD
STILL OCCUR -- SOME LOW END POPS WILL BE KEPT IN THE FORECAST.
ON WEDNESDAY, THE LOW WILL BE IN THE PROCESS OF OPENING INTO A WAVE,
WITH THE AXIS SHIFTING EAST OF THE ILN CWA BY MID-DAY. DESPITE THIS,
THE ENVIRONMENT WILL REMAIN MOIST AND SOMEWHAT UNSTABLE -- SO EVEN IN
THE ABSENCE OF FORCING, DIURNAL CONVECTION IS AGAIN LIKELY TO OCCUR.
WILL KEEP POPS A LITTLE LOWER THAN TUESDAY, OWING TO THE WEAKER
FORCING. HAZARDOUS WEATHER APPEARS UNLIKELY AS OF NOW, THOUGH THERE
WOULD LIKELY REMAIN A LOW-END ISOLATED THREAT FOR HEAVY RAIN. HIGHS
SHOULD BE A COUPLE DEGREES WARMER THAN TUESDAY, GENERALLY IN THE MID
70S.
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
WEDNESDAY NIGHT, THE SURFACE PRESSURE PATTERN BEGINS TO FINALLY LOSE
THE FINAL REMNANTS OF THE SURFACE LOW PRESSURE ASSOCIATED WITH THE
UPPER LEVEL CLOSED LOW THAT HAD LINGERED FOR SEVERAL DAYS OVER THE
OHIO VALLEY. HIGH PRESSURE TO THE EAST AND A SURFACE LOW PRESSURE
DIGGING INTO THE NORTHERN AND CENTRAL PLAINS PROVIDES LIGHT
SOUTHEASTERLY FLOW INTO THURSDAY MORNING. OVERNIGHT LOW TEMPERATURES
LARGELY REMAIN IN THE LOWER 60S WITH SOME MID AND UPPER 50S IN THE
FAR EAST (SCIOTO VALLEY).
SEVERE POTENTIAL (ROUND 1): THURSDAY AFTERNOON, MID-LEVEL RIDGING
BUILDS OVER THE OHIO VALLEY, SUPPORTING ABOVE NORMAL TEMPERATURES IN
THE LOW TO MID 80S. SOME CLOUD COVER LIKELY LIMITS TEMPERATURES A FEW
DEGREES AS WARM AIR ADVECTION ALOFT INCREASES OVER THE REGION,
CAUSING MORE CLOUD COVER. DURING THE EVENING HOURS, THE LOW PRESSURE
AND TROUGH REMAIN WELL TO THE NORTHWEST OF THE REGION, LOCATED ACROSS
THE UPPER MIDWEST (MINNESOTA & WISCONSIN). THIS PRESENTS A CHALLENGE
REGARDING THE OVERALL STRENGTH OF THE FORCING OVER THE LOCAL AREA.
STEEP MID-LEVEL LAPSE RATES AND SURFACE DEWPOINTS IN THE UPPER 60S
PROVIDES A POOL OF MODERATE TO HIGH INSTABILITY, BUT A FORCING
MECHANISM TO PUSH SURFACE AIR THROUGH THE WARM AIR ADVECTION
INVERSION IS LACKING. SOME HEIGHT FALLS SUPPORT BROAD ASCENT, WHICH
MAY BE ENOUGH TO TRIGGER ELEVATED CONVECTION ACROSS ILLINOIS AND
INDIANA. THROUGHOUT THE EVENING, THIS ACTIVITY WILL ATTEMPT TO ENTER
THE LOCAL FORECAST AREA, WITH HIGHEST CHANCES ACROSS THE FAR WEST,
ESPECIALLY THE NORTHWEST AND NORTH. STEEP MID-LEVEL LAPSE RATES AND
STRONG SHEAR SUPPORT THE POTENTIAL FOR STRONG UPDRAFTS AND LARGE
HAIL. DAMAGING WINDS MAY ALSO BE A THREAT, BUT WIDESPREAD ACTIVITY
DOESN'T APPEAR LIKELY AT THIS TIME.
AN OCCLUDED COLD FRONT MOVES THROUGH THE AREA THURSDAY NIGHT INTO
FRIDAY MORNING, WITH SOME UNCERTAINTY AS TO HOW FAR SOUTH IT
ADVANCES. THIS BRINGS US INTO THE UNCERTAINTY FOR FRIDAY...
SEVERE POTENTIAL (ROUND 2): FRIDAY MORNING, THE SAME OCCLUDED LOW
PRESSURE IS STILL POSITIONED OVER THE UPPER MIDWEST, SLIDING SLOWLY
EASTWARD INTO THE GREAT LAKES REGION BY THE EVENING. DEPENDING ON ITS
LOCATION, THE ABILITY FOR MORE MOISTURE-CHARGED AIR TO MOVE
NORTHWARD IS HIGHLY DEPENDENT. NBM PROBABILITIES FOR AT LEAST 1000
J/KG OF MLCAPE AND AT LEAST 40 KNOTS OF BULK SHEAR CONTINUES TO
INCREASE FOR FRIDAY AFTERNOON AND EVENING. THIS IS DIRECTLY TIED TO A
POOL OF UPPER 60S DEWPOINTS THAT MOVES NORTHWARD, BACK INTO THE
LOCAL AREA, BEHIND THE THURSDAY NIGHT/FRIDAY MORNING COLD FRONT. IF
THE MOISTURE IS ABLE TO RETURN, A SHORTWAVE TROUGH ADVANCING THROUGH
THE SOUTHERN PERIPHERY OF THE TROUGH WILL INITIATE THE SECOND
POTENTIAL SEVERE THREAT. GIVEN THE LOCATION OF THE SHORTWAVE,
FAVORABLE MOISTURE AND STRONG SHEAR, THERE APPEARS TO BE A HIGHER
SEVERE WEATHER POTENTIAL FRIDAY WHEN COMPARED TO THURSDAY. AS THE
MOST AGGRESSIVE SOLUTION, THE 00Z GFS DEPICTS A "HIGHER-END" SCENARIO
WITH A WELL ORGANIZED MCS TARGETING AREAS FROM SOUTH CENTRAL INDIANA
INTO THE SOUTHERN OHIO.
UNCERTAINTY: COMPARING THE AGGRESSIVE SOLUTIONS TO THE LESS
CONCERNING OUTCOMES REVEALS THE PLACEMENT OF THE PRIMARY TROUGH OVER
THE MIDWEST IS CRITICAL. RETURNING AIR MASS SCENARIOS ALWAYS CARRY
VERY LOW CONFIDENCE BECAUSE CONVECTIVELY DRIVEN COLD POOLS AND/OR
COLD FRONT ALMOST ALWAYS RESOLVE FARTHER SOUTH, MAKING IT DIFFICULT
FOR MOIST AIR TO RETURN NORTH. TRENDS TO MONITOR WILL BE THE EASTWARD
ADVANCEMENT OF THE TROUGH FRIDAY EVENING. THE FARTHER EAST, THE MORE
CHALLENGING IT WILL BE FOR MOISTURE TO RETURN NORTHWARD. THE
SHORTWAVE TROUGH WILL STILL PROVIDE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS, BUT THE POTENTIAL FOR WIDESPREAD SEVERE IMPACTS WOULD
BE LOWER. THE MOST RECENT 00Z ECMWF ENS TRENDED SLIGHTLY SLOWER
(FARTHER WEST) WITH THE TROUGH, BUT STILL ISN'T AS SLOW AS THE GEFS.
WHATEVER OCCURS FRIDAY NIGHT WILL ULTIMATELY PROVIDE A PUSH OF
MOISTURE SOUTH OF THE REGION FOR THE WEEKEND. THE TROUGH WILL
CONTINUE ITS EASTWARD PROGRESSION ACROSS THE GREAT LAKES WITH WEAKLY
AMPLIFIED JET STREAM FLOW OVER THE OHIO VALLEY. LOWER CHANCES FOR
SHOWERS/THUNDERSTORMS ARE FORECAST FOR THE WEEKEND, WITH MUCH OF THE
ACTIVITY FOCUSED TO THE SOUTH AND EAST. TEMPERATURES ARE MORE
SEASONABLE SUNDAY AND MONDAY BEFORE THE NEXT RIDGE BUILDS IN TUESDAY.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
CONVECTIVE INITIATION HAS OCCURRED ACROSS THE REGION AS OF THE 18Z
ISSUANCE WITH ISOLATED COVERAGE. BASED ON THE LATEST HIGH-RESOLUTION
GUIDANCE, COVERAGE IS LIKELY TO INCREASE THROUGH LATE AFTERNOON
BEFORE STARTING TO DECREASE HEADING INTO THE EVENING. A FEW OF THESE
STORMS MAY CONTAIN HEAVY RATES OF RAINFALL, SO HAVE VISIBILITY
RESTRICTIONS INCLUDED ACCORDINGLY.
OUTSIDE OF A FEW SHOWERS, THE OVERNIGHT WILL BE COMPARATIVELY QUIET.
WINDS WILL CONTINUE TO BE VERY LIGHT UNDER THE BROAD UPPER LOW.
IN THE MOIST ENVIRONMENT, CEILINGS ARE EXPECTED TO DROP TO MVFR
LEVELS BY MORNING.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE WEDNESDAY AFTERNOON, THEN AGAIN
AT TIMES FROM THURSDAY NIGHT THROUGH SATURDAY. MVFR CEILINGS ARE
POSSIBLE WEDNESDAY MORNING.
ILN WATCHES/WARNINGS/ADVISORIES
OH...NONE.
KY...NONE.
IN...NONE.
SYNOPSIS...HATZOS
NEAR TERM...
SHORT TERM...HATZOS
LONG TERM...MCGINNIS
AVIATION...
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