520
FXUS61 KILN 211737
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
1237 PM EST SUN DEC 21 2025
SYNOPSIS
MILD CONDITIONS WILL PREVAIL THROUGH THE UPCOMING WEEK, WITH MUCH
ABOVE NORMAL TEMPERATURES BY MIDWEEK THROUGH THE END OF THE WEEK.
SEVERAL WEAK SYSTEMS WILL PROVIDE OPPORTUNITIES FOR LIGHT RAIN,
INCLUDING MONDAY NIGHT INTO TUESDAY AND AGAIN WEDNESDAY NIGHT INTO
THURSDAY AS WELL AS FRIDAY. HOWEVER, THE OVERALL PATTERN WILL REMAIN
SOMEWHAT TRANQUIL UNTIL A COLD FRONT PROGRESSES THROUGH THE REGION
BY THIS UPCOMING WEEKEND, WHICH WILL BRING COLDER CONDITIONS BACK TO
THE REGION.
NEAR TERM /THROUGH TONIGHT/
SURFACE HIGH PRESSURE WILL SETTLE INTO THE OH VLY THROUGH TONIGHT,
PROVIDING LIGHT/CALM WIND AND MAINLY CLEAR SKIES. GOOD RADIATIONAL
COOLING CONDITIONS ARE EXPECTED TONIGHT, ALLOWING TEMPS TO DIP INTO
THE UPPER TEENS IN CENTRAL OH TO THE LOWER/MID 20S ELSEWHERE.
SHORT TERM /MONDAY THROUGH MONDAY NIGHT/
THE SURFACE HIGH PRESSURE WILL DRIFT OFF TO THE E OF THE REGION INTO
EARLY MONDAY, WITH DEEP-LAYER WSW FLOW BECOMING RE-ESTABLISHED ONCE
AGAIN AHEAD OF A WEAK SYSTEM THAT WILL BRING LIGHT RAIN TO THE AREA
MONDAY NIGHT INTO EARLY TUESDAY.
THE STRENGTHENING SW FLOW WILL HELP BRING SOME MOISTURE BACK INTO
THE AREA THROUGH THE DAYTIME, WITH A GRADUAL MOISTENING OF THE COLUMN
INTO MID/LATE AFTERNOON. THE BETTER LL MOISTURE WILL ARRIVE INTO
MONDAY EVENING/NIGHT, WITH SUFFICIENT FORCING/MOISTURE TO ALLOW FOR
SOME POCKETS OF LIGHT RAIN TO OVERSPREAD THE AREA FROM THE SW. THIS
LIGHT RAIN WILL PERSIST THROUGH THE OVERNIGHT INTO TUESDAY MORNING,
POTENTIALLY LINGERING IN N KY INTO THE AFTERNOON, WITH TOTAL
RAINFALL AMOUNTS GENERALLY AROUND ONE TENTH OF AN INCH TO AS MUCH AS
TWO TENTHS OF AN INCH (ESPECIALLY NEAR/S OF THE OH RVR).
LL SATURATION WILL BECOME WIDESPREAD BY DAYBREAK TUESDAY FOR MUCH OF
THE AREA, SO SOME BRIEF BR/FG MAY BE POSSIBLE AMIDST THE PATCHIER
LIGHT RAIN.
LONG TERM /TUESDAY THROUGH SUNDAY/
AN UPPER LEVEL RIDGE OVER THE PLAINS WILL KEEP NW FLOW OVER THE OHIO
VALLEY. THIS WILL ALLOW ENERGY TO TOP THE RIDGE AND SLIDE SE INTO
THE REGION ALONG WITH OCCASIONAL PERIODS OF RAINFALL, NOTABLY WED
NIGHT AND AGAIN ON FRIDAY. AN UNUSUALLY LARGE RANGE FOR POPS EXISTS
IN THE EUROPEAN ENSEMBLE. TO WIT, MOS GUIDANCE AT CMH FOR THE
EUROPEAN SHOWS A 17 SIGMA RANGE FOR WED NIGHT - 69% TO 0%. THESE
HIGH DEVIATIONS PERSIST FOR THE REMAINDER OF THE FORECAST, WITH A 14
SIGMA SHOWN FRIDAY, AND A 14-16 SIGMA SAT NIGHT/SUN.
WHILE THE UNCERTAINTY IS HIGH, THE TREND AND SUBSEQUENT FORECASTS
NEED TO ERR TOWARDS THESE HIGHER VALUES. LOOKING AT CMH AS A PROXY,
ENSEMBLE MOS FOR THE EURO HAS A STANDARD OF DEVIATION FROM WED NIGHT
ONWARD AT A 5 OR HIGHER, MAXING AT AN 8 ON SATURDAY (65% VS 12%).
ALL OF THIS BEING SAID, THERE IS A CONTINGENCY OF LOWER POPS THAT
SEEM TO BE IGNORED WED NIGHT. EURO MOS HIGHEST MEMBER AT THIS TIME
SHOWS 69% POP, WITH THE NBM COMING IN AT A WHOPPING 86%. GIVEN THE
LARGE INFLUENCE OF THE EURO IN THE NBM AT THIS TIME FRAME, I'M
UNCERTAIN AS TO HOW AN AVERAGE POP OF 42% AND MEAN OF 41% COULD
POSSIBLY RESULT IN NBM OUTPUT OF 86%.
MY MAIN TAKEAWAY IS NBM POPS WED NIGHT SEEM EXCESSIVE, ESPECIALLY
WHEN VIEWING REMAINDER OF CWA VS CMH WHERE THE BEST CHANCE DOES LIE.
AS TO BE EXPECTED, TEMPERATURE SIGMAS START AT 5 STANDARD DEVIATIONS
WED NIGHT AND REMAIN ABOVE 6 GOING FORWARD IN TIME, WITH SATURDAY
BEING AN 8 (66 DEGREES VS 39 DEGREES). WHILE NBM IS CLOSER TO THE
50TH PERCENTILE IN THE EXTENDED, IT JUST STANDS TO REASON THAT THE
FORECAST BEYOND WED IS LOW ON CONFIDENCE.
TUESDAY WILL BE WARM-SECTORED WITH SW SFC FLOW AHEAD OF A WEAK CDFNT
THAT ESSENTIALLY TURNS WIND WLY AND INTRODUCES DRIER AIR. HIGH
PRESSURE STRENGTHENS OVER WI WITH A RIDGE NOSING TOWARDS CVG METRO
OVERNIGHT. WED STARTS WITH THE HIGH CENTERED IN/JUST N OF OH AND A
SHIFT TO ELY SFC WIND. WHILE INCREASED UNCERTAINTY BEGINS WED NIGHT,
A WMFNT LOOKS TO BE SETTING UP OVER NRN OH AND DOES INDICATE A
BETTER CHANCE OF RAIN OVER NRN CWA, THOUGH NOT AS EXCESSIVE AS NBM.
AVIATION /18Z SUNDAY THROUGH THURSDAY/
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD, ALTHOUGH SUPPOSE
SOME RIVER VALLEY BR/FG CANNOT BE RULED OUT AT KLUK. ALTHOUGH THE
AIR IS VERY DRY, THE CALM WINDS AND MAINLY CLEAR SKIES MAY PROVIDE
AN OPPORTUNITY FOR SOME LOCAL/BRIEF VSBY REDUCTIONS AT THE SITE.
OTHERWISE, SOME CIRRUS WILL PROGRESS THROUGH THE REGION FROM TIME-TO-
TIME THROUGH THE OVERNIGHT BEFORE AN AXIS OF MIDLEVEL CLOUDS PIVOTS
E THROUGH THE AREA PAST DAYBREAK MONDAY. THE RAPID MOISTENING OF THE
COLUMN, WITH A TRANSITION OF CIGS FROM VFR TO MVFR/IFR, WILL HOLD
OFF UNTIL AFTER 00Z TUESDAY.
LIGHT NORTHERLY WINDS THROUGH LATE AFTERNOON WILL GO LIGHT/VRB/CALM
TONIGHT AS THE SFC HIGH TRAVERSES THE REGION. FLOW WILL GO OUT OF
THE SE AROUND 5-8KTS PAST 15Z MONDAY.
OUTLOOK...IFR CIGS, WITH MVFR VSBYS, ARE LIKELY MONDAY NIGHT INTO
TUESDAY MORNING. MVFR/IFR CIGS WILL BE POSSIBLE AGAIN WEDNESDAY NIGHT
INTO THURSDAY.
ILN WATCHES/WARNINGS/ADVISORIES
OH...NONE.
KY...NONE.
IN...NONE.
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...FRANKS
AVIATION...
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