202
FXUS61 KILN 182317
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
717 PM EDT MON AUG 18 2025
SYNOPSIS
SURFACE HIGH PRESSURE BUILDING ACROSS THE GREAT LAKES WILL OFFER DRY
WEATHER AND NEAR NORMAL TEMPERATURES TODAY. MORE HUMID AND WARMER
CONDITIONS ARRIVE TUESDAY AND WEDNESDAY ALONG WITH AN INCREASING
THREAT FOR SHOWERS AND STORMS. IN THE WAKE OF A COLD FRONT SLIGHTLY
COOLER AND DRIER CONDITIONS ARE EXPECTED THURSDAY AND FRIDAY.
CANADIAN HIGH PRESSURE LOOKS TO OFFER COOLER AND DRIER AIR LATE THIS
WEEKEND INTO EARLY NEXT WEEK.
NEAR TERM /THROUGH TUESDAY/
A LARGE MID LEVEL RIDGE EXTENDS FROM THE CENTRAL AND SOUTHERN PLAINS
INTO THE LOWER OHIO VALLEY WITH A BAND OF WESTERLIES FROM THE
NORTHERN PLAINS THRU THE GREAT LAKES. LATEST SURFACE ANALYSIS SHOWS A
STALLED FRONTAL BOUNDARY EXTENDING FROM CENTRAL KY THRU IL INTO THE
MID MS VALLEY WITH HIGH PRESSURE CENTERED JUST NORTH OF THE GREAT
LAKES. IN THE WAKE OF THIS FRONT DRIER AIR HAS ADVECTED INTO THE
REGION ON LOW LEVEL NORTHERLY FLOW. STRATUS THAT DEVELOPED OVERNIGHT
IS MIXED OUT LEAVING SCATTERED TO BKN CUMULUS CLOUDS.
THESE DIURNALLY DRIVEN CUMULUS CLOUDS WILL DISSIPATE WITH THE LOSS
OF HEATING EARLY THIS EVENING WITH ONLY SOME THIN HIGH LEVEL CLOUDS
SPILLING IN OVERNIGHT. SOME PATCHY FOG CANNOT BE RULED OUT IN IN
RIVER VALLEYS TONIGHT.
TEMPERATURES TONIGHT WILL BOTTOM OUT FROM THE UPPER 50S NORTHEAST TO
THE UPPER 60S SOUTHWEST.
SHORT TERM /TUESDAY NIGHT/
MID LEVEL SHORTWAVE OVER THE UPPER MS VALLEY TO TRACK EAST THRU THE
GREAT LAKES TUESDAY/TUESDAY NIGHT. EXPECT THUNDERSTORMS TO DEVELOP
TO OUR WEST IN A THERMALLY MORE FAVORABLE ENVIRONMENT TUESDAY AND
THEN PROGRESS EASTWARD ON THE LEADING EDGE OF MORE HUMID AIR (WITH
FRONT LIFTING BACK NORTH) - AS MODERATE INSTABILITY DEVELOPS. THE
HIGHEST POPS WILL OCCUR GENERALLY WEST OF I-71. HIGHS ON TUESDAY WILL
TOP OUT IN THE UPPER 80S TO NEAR 90 DEGREES. HAVE ADJUSTED NBM
TEMPERATURES AND DEWPOINTS DOWN SLIGHTLY (MAINLY ACROSS THE SOUTH)
DUE TO RECENT OBSERVATIONAL TRENDS.
WEAK SURFACE LOW ASSOCIATED WITH THE MID LEVEL SHORTWAVE TRACKS
ACROSS THE GREAT LAKES WITH A SOUTHWARD ATTENDANT FRONT PUSHING INTO
THE AREA LATE TUESDAY NIGHT. SHOWER AND THUNDERSTORM CHANCES
OVERSPREAD THE ENTIRE AREA WITH THE HIGHEST POPS ACROSS THE NORTH -
CLOSER TO THE SURFACE LOW. LOW TEMPERATURES TUESDAY NIGHT DROP TO
READINGS RANGING FROM THE UPPER 60S TO THE LOWER 70S.
LONG TERM /WEDNESDAY THROUGH MONDAY/
COLD FRONT CONTINUES TO PUSH SOUTHEAST THROUGH SOUTH-CENTRAL OHIO
AND NORTHEAST KENTUCKY COUNTIES WEDNESDAY MORNING, LEADING TO LIGHT
NORTHERLY FLOW AND ADVECTION OF SLIGHTLY DRIER AIR. ENSEMBLE
GUIDANCE MAINTAINS A LOW CHANCE OF SHOWERS/STORMS DUE TO SOME
UNCERTAINTY IN FRONTAL POSITION, SO HAVE KEPT THESE POPS UNTIL
CONFIDENCE IMPROVES.
WHILE SURFACE DEWPOINTS REMAIN QUITE HIGH LATE THIS WEEK INTO THE
EARLY STAGES OF THE WEEKEND, MOISTURE DEPTH IS SHALLOW AS PWS DROP
TO NEAR OR JUST BELOW AN INCH. LATEST GUIDANCE OFFERS A SLIGHT
CHANCE OF CONVECTION ALONG A REINFORCING COLD FRONT SATURDAY
AFTERNOON... BUT THIS WILL LIKELY BE DEPENDENT ON THE EXACT TIMING
OF THE FRONT AND HOW MUCH MOISTURE RETURN CAN OCCUR AHEAD OF IT.
BEHIND THIS REINFORCING COLD FRONT, HIGH PRESSURE WILL DROP SOUTH
INTO THE NORTHERN PLAINS TO CLOSE THE PERIOD. THIS FRONT LEADS THE
MIDDLE OHIO VALLEY INTO COOLER TEMPERATURES AND MUCH LOWER DEWPOINTS
HEADING INTO THE NEXT WORK WEEK.
AVIATION /23Z MONDAY THROUGH SATURDAY/
VFR CONDITIONS TO START THE PERIOD WITH LIGHT NORTHEASTERLY FLOW
AROUND 5 KNOTS OR LESS. DIURNALLY DRIVEN CU DISSIPATE AS WE HEAD
INTO THE OVERNIGHT. CANNOT RULE OUT SOME RIVER VALLEY FOG,
PARTICULARLY AT KLUK AND AREAS WHERE MOISTURE SOURCES ARE MORE
ABUNDANT. PM GUIDANCE HAS BACKED OFF A BIT ON OVERLAND FOG (OTHER
THAN THE SCIOTO RIVER VALLEY, WHICH IS WELL SOUTH AND EAST OF ANY TAF
SITES). THEREFORE, HAVE HEDGED TOWARD A VFR FORECAST FOR OTHER
SITES, BUT THIS MAY NEED TO CHANGE.
FLOW VEERS AROUND TO BECOME MORE SOUTHWESTERLY ON TUESDAY, AROUND 10
KNOTS OR LESS, AHEAD OF AN APPROACHING SYSTEM. DIURNAL CU CAN BE
EXPECTED DURING THE LATE MORNING HOURS BEFORE HIGH LEVEL CLOUD
BLOWOFF BEGINS TO SPILL IN FROM THE WEST. SCATTERED THUNDERSTORMS
WILL BEGIN TO POP UP DURING THE AFTERNOON HOURS, CONTINUING INTO THE
EVENING. HAVE HANDLED THIS WITH PROB 30S.
OUTLOOK...MVFR AND POSSIBLY IFR CIGS ARE POSSIBLE TUESDAY OVERNIGHT
INTO WEDNESDAY. THUNDERSTORMS ARE ALSO POSSIBLE TUESDAY NIGHT AND
WEDNESDAY.
ILN WATCHES/WARNINGS/ADVISORIES
OH...NONE.
KY...NONE.
IN...NONE.
SYNOPSIS...AR
NEAR TERM...AR
SHORT TERM...AR
LONG TERM...
AVIATION...CA
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