774
FXUS61 KILN 191112
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
612 AM EST SUN JAN 19 2025
SYNOPSIS
SNOW AND SOME HEAVIER SNOW SHOWERS ARE EXPECTED THROUGH TODAY
AHEAD OF AN ARCTIC FRONT THAT WILL REACH THE AREA BY THE
AFTERNOON AND EVENING HOURS. BITTERLY COLD CONDITIONS WILL THEN
BE IN PLACE TONIGHT THROUGH WEDNESDAY MORNING, WITH DRY
CONDITIONS EXPECTED THROUGH MIDWEEK. A SLIGHT WARMING TREND IS
EXPECTED BY THE END OF THE WORKWEEK, WITH MORE SEASONABLE AIR
FILTERING BACK INTO THE OHIO VALLEY.
NEAR TERM /UNTIL 6 PM THIS EVENING/
THE SETUP FOR TODAY APPEARS TO HAVE CHANGED VERY LITTLE WITHIN
THE PAST SEVERAL FCST CYCLES, WITH THE PLACEMENT OF THE WINTER
WEATHER ADVISORY ALIGNING WITH GREATEST PROBABILITIES FOR AT
LEAST 1" OF SNOW. THERE HASN'T BEEN ANY SIGNIFICANT SHIFT N OR
S IN THE LATEST GUIDANCE THAT WOULD NECESSITATE A CHANGE TO
HEADLINES, SO THE ADVISORY WILL REMAIN AS IS FOR NOW.
THAT BEING SAID, THERE IS STILL THE CONCERN FOR SCATTERED TO
NUMEROUS SNOW SHOWERS/SQUALLS THIS AFTERNOON, INTO EARLY
EVENING, WITH THE MULTI-FORM WINTRY IMPACTS TODAY DESCRIBED
BELOW.
1) A S/W ROUNDING THE BASE OF THE EXPANDING/DIGGING LONGWAVE
TROF WILL PIVOT E INTO THE SRN OH VLY EARLY THIS MORNING,
PROMOTING THE DEVELOPMENT OF A SFC LOW AND ENHANCING LL
FRONTOGENESIS. ADDITIONALLY, THIS WILL SPREAD DEEP-LAYER ASCENT
INTO A STILL AMPLY-SATURATED LL PROFILE. THIS WILL ENCOURAGE
THE DEVELOPMENT OF A LARGE BAND OF SN, WHICH SHOULD PIVOT TO THE
NE THROUGH KY INTO FAR SRN OH BY DAYBREAK THIS MORNING,
BRINGING LIGHT ACCUMULATING SNOW TO THE SE QUARTER OR SO OF THE
ILN FA. WHILE THERE IS STILL A TAD OF UNCERTAINTY REGARDING
LATITUDINAL PLACEMENT OF THIS BAND, ESPECIALLY AS SOME LL DRY
AIR WILL NEED TO BE OVERCOME ON THE NRN EDGE, LATEST GUIDANCE
HAS COME INTO BETTER ALIGNMENT REGARDING THE NRN PERIPHERY OF
THE BETTER ACCUMULATING SNOW. GREATEST PROBABILITIES FOR 1-2"
OF SNOW REMAIN WITHIN A CORRIDOR FROM ROBERTSON CO KY THROUGH
HOCKING CO OH AND POINTS TO THE S (ESPECIALLY MASON/LEWIS COS KY
AND ADAMS/SCIOTO COS OH). GIVEN ABOVE-CLIMO SLRS ON THE ORDER
OF ~15:1, EVEN A TENTH OR TWO OF LIQUID- EQUIVALENT PCPN WOULD
TRANSLATE INTO A BROAD AXIS OF 1.5" TO AS MUCH AS 3" WITHIN THIS
CORRIDOR THROUGH 18Z. THIS BEING SAID, THERE WILL STILL LIKELY
BE AN AXIS JUST N OF THE CURRENT ADVISORY LAYOUT, SAY FROM
SWITZERLAND CO IN THROUGH HIGHLAND CO OH, WHERE SOME SPOTS MAY
PICK UP AN INCH. FURTHER TO THE N, INTO THE TRI- STATE AND
ALONG THE I-71 CORRIDOR IN OH, THE PROBABILITIES OF AN INCH OF
SNOW DROP OFF RATHER ABRUPTLY AND WOULD ANTICIPATE VERY LITTLE,
IF ANY, SNOW FROM THIS FEATURE FROM CINCY TO WILMINGTON TO
COLUMBUS.
2) REGARDLESS OF WHETHER ANY ONE SPOT RECEIVES A FEW INCHES OF
SNOW THIS MORNING INTO EARLY AFTERNOON OR NOT, IT IS SHAPING UP
TO BE A COLD AND BLUSTERY DAY AREA-WIDE, WITH INCREASINGLY
STEEP LL LAPSE RATES COINCIDING WITH ENHANCED FORCING AS A
MIDLEVEL S/W SWINGS THROUGH THE AREA. GOOD SATURATION WITHIN THE
DGZ AND SUFFICIENT LIFT WITHIN THE DGZ SUGGEST THAT SHSN
ACTIVITY SHOULD BE FAIRLY WIDESPREAD BY THIS AFTERNOON INTO THE
EVENING. OF PARTICULAR CONCERN IS SEVERAL FOCUSED N-S ORIENTED
BANDS OF SHSN ACTIVITY ALONG THE LEADING EDGE OF THE INCREDIBLY
DEEP/SHARP PV ANOMALY, WHICH WILL MOVE E THROUGH THE AREA MID
AFTERNOON (NEAR/W OF I-75) INTO THE EVENING (CENTRAL OH INTO NE
KY). THIS SIGNAL IS SO STRONG THAT IT IS STILL APPEARING WITHIN
SEVERAL COARSE SYNOPTIC QPF PLOTS, SUGGESTING THAT THE SHSN
ACTIVITY COULD BE LOCALLY INTENSE. BOTTOM LINE IS THAT WE WILL
LIKELY BE DEALING WITH SOME SNOW SQUALLS THIS AFTERNOON INTO THE
EVENING, WITH LL TEMP PROFILES MORE-THAN-SUPPORTIVE FOR
EFFICIENT ACCUMULATION ON ROADS AND THE OVERALL SETUP BEING
FAVORABLE FOR IMPACTFUL SHSN/SQUALL ACTIVITY. AS WITH THESE
SETUPS, IT IS NOT ABOUT THE AMOUNTS, BUT RATHER THE RAPID CHANGE
IN CONDITIONS THAT COME WITH THE PASSAGE. WILL CONTINUE
HIGHLIGHTING THIS POTENTIAL IN THE HWO AND WITH AN SPS.
THE MAIN TAKEAWAY HERE IS THAT THERE ARE LIKELY TO BE IMPACTS
FROM SHSN/SQUALLS THIS AFTERNOON/EVENING ACROSS A MUCH BROADER
PORTION OF THE LOCAL AREA THAN WILL SEE THE MORNING LIGHT
ACCUMULATING SNOW. AT THIS TIME, THE CURRENT WINTER WEATHER
ADVISORY LOOKS WELL PLACED GIVEN LATEST PROBS. WILL HIGHLIGHT
BOTH THREATS IN THE HWO AND OTHER MESSAGING PLATFORMS AS THE
SNOW SQUALL POTENTIAL WILL LIKELY BE THE GREATEST CONCERN
THROUGH THE NEAR TERM PERIOD.
TEMPS WILL RANGE FROM THE LOWER 20S (NW) TO THE UPPER 20S (SE)
ON SUNDAY, WITH A NEGLIGIBLE DIURNAL RISE FOR MOST SPOTS. GUSTY
WNW WINDS TO 25-30 MPH ARE EXPECTED LATE AFTERNOON THROUGH
MIDNIGHT WITH THE ARRIVAL OF THE COLDER AIR.
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/
FOR TONIGHT, AFTER THE EVENING SHSN/SQUALL ACTIVITY PUSHES TO
OUR E, THE ARCTIC AIR RUSHES IN, BRINGING AIR TEMPS CLOSE TO
ZERO, OR PERHAPS SEVERAL DEGREES BELOW ZERO, BY DAYBREAK MONDAY.
STEADY WNW FLOW THROUGH THE NIGHT AT 12-15 MPH, WITH GUSTS TO
AROUND 25 MPH, WILL CREATE WIND CHILL VALUES VERY CLOSE TO
WARNING CRITERIA (-15F NEAR/S OF OH RVR AND -20F NEAR/N OF I-70)
AROUND 12Z MONDAY.
THIS BEING SAID, PROBABILITIES FOR MEETING OR EXCEEDING WARNING
CRITERIA HAVE STEADILY GONE DOWN OVER THE PAST FEW FCST CYCLES,
WITH THE MOST LIKELY OUTCOME BEING MEETING WARNING CRITERIA IN
ANY ONE LOCATION FOR PERHAPS ONLY AN HOUR OR TWO, IF AT ALL.
THERE IS A FAIRLY CONSISTENT SIGNAL FOR A SLIGHTLY WARMER SETUP
MONDAY NIGHT INTO TUESDAY, WHERE SOME LOCALES MAY NOT EVEN REACH
ADVISORY (-5F NEAR/S OF OH RVR AND -10F NEAR/N OF I-70)
CRITERIA. THE SHRINKING TIMELINE REQUIRES SOME SORT OF
RESOLUTION TO THE ONGOING EXTENDED EXTREME COLD WATCH, WHICH
LATEST GUIDANCE SUGGESTS THE BEST COURSE OF ACTION MAY BE A
COLD WEATHER ADVISORY AREA-WIDE FROM TONIGHT THROUGH WEDNESDAY
MORNING, EVEN RECOGNIZING THERE /WILL LIKELY/ BE A FEW SPOTS
WHERE WARNING CRITERIA IS BRIEFLY BE MET/EXCEEDED BOTH MONDAY
AND WEDNESDAY MORNINGS. CONFIDENCE IS HIGH THAT THIS PERIOD WILL
FEATURE LARGE IMPACTS DUE TO THE COLD CONDITIONS, THOUGH
CONFIDENCE IS ONLY MEDIUM IN SPECIFIC VALUES -- PARTICULARLY
WHEN DEALING WITH WIND CHILLS DUE TO ITS DEPENDENCE ON TWO OTHER
ELEMENTS (TEMPERATURES AND WIND SPEEDS).
HIGHS ON MONDAY REBOUND INTO THE SINGLE DIGITS ABOVE ZERO
(NEAR/N OF I-70) TO THE LOWER/MID TEENS NEAR/S OF THE OH RVR
AMIDST MOSTLY SUNNY SKIES.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
ON MONDAY EVENING, BROAD TROUGHING WILL REMAIN IN PLACE ACROSS THE
EASTERN TWO-THIRDS OF THE CONUS, WITH ARCTIC HIGH PRESSURE
STRETCHING FROM THE CENTRAL PLAINS THROUGH THE MID-ATLANTIC REGION.
THE FOCUS FOR THE FIRST HALF OF THE WEEK REMAINS ON THE VERY COLD
WEATHER ASSOCIATED WITH THIS ARCTIC AIR MASS. A COLD WEATHER
ADVISORY IS IN EFFECT THROUGH THE COLDEST PART OF THE WEEK, ENDING
ON WEDNESDAY MORNING.
THIS PART OF THE FORECAST WILL FOCUS ON TEMPERATURE AND WIND CHILL
CONDITIONS ON TUESDAY AND WEDNESDAY MORNINGS. GETTING INTO THE
DETAILS, ONE SEPARATE SECTION OF THE SURFACE HIGH WILL BE IN PLACE
MONDAY, MOVING EASTWARD BY TUESDAY MORNING AS A WEAK TROUGH OR
FRONTAL BOUNDARY MOVES THROUGH THE AREA. A SECOND SURFACE HIGH WILL
THEN RE-ESTABLISH ITSELF ACROSS THE OHIO VALLEY LATER TUESDAY INTO
WEDNESDAY MORNING. IT IS INTERESTING THAT ON TUESDAY MORNING, AHEAD
OF THE SURFACE TROUGH, BOUNDARY LAYER FLOW WILL BRIEFLY SHIFT TO THE
SOUTHWEST -- PROVIDING A PERIOD OF WEAK WARM ADVECTION THAT WILL
RESULT IN TUESDAY AM TEMPERATURES BEING A LITTLE WARMER THAN MONDAY
OR WEDNESDAY. WITH THAT SAID, TEMPERATURES TUESDAY MORNING WILL
STILL BE IN THE SINGLE DIGITS TO NEAR ZERO. WIND CHILL VALUES
RANGING FROM 0F TO -10F ON TUESDAY MORNING MAY BE JUST SHY OF THE
PRODUCT CRITERIA FOR A COLD WEATHER ADVISORY, BUT BASED ON THE
CONTINUED COLD CONDITIONS THROUGH THE DAYTIME HOURS AND THEN THE
EXPECTATION OF COLDER TEMPERATURES TUESDAY NIGHT INTO WEDNESDAY
MORNING, THE ADVISORY WILL CONTINUE THROUGH THIS ENTIRE TIME SPAN.
THE COLDEST RAW TEMPERATURES OF THE WEEK WILL LIKELY OCCUR WEDNESDAY
MORNING, WITH LIGHTER WINDS AND MOSTLY CLEAR SKIES LEADING TO IDEAL
RADIATIONAL COOLING CONDITIONS. TEMPERATURES ON WEDNESDAY MORNING
LOOK TO BE BELOW ZERO FOR THE VAST MAJORITY OF THE FORECAST AREA,
WITH SOME VALUES APPROACHING -10F IN CENTRAL OHIO. DESPITE THE
LIGHTER WINDS, WIND CHILLS MAY AGAIN APPROACH -20F IN THE NORTHERN
PARTS OF THE ILN FORECAST AREA. EXACT WIND CHILL VALUES MAY VARY A
BIT FROM PLACE TO PLACE, AS SMALL CHANGES IN WINDS (WHICH MAY RANGE
FROM CALM TO AROUND 5MPH) CAN CHANGE THE WIND CHILL CALCULATION BY
SEVERAL DEGREES. LOCAL GEOGRAPHY AND ANY LEFTOVER SNOW PACK CAN ALSO
LEAD TO VARIANCE IN MIN TEMPS UNDER FAVORABLE RADIATIONAL COOLING
CONDITIONS. SO, WHILE SPECIFIC MIN TEMPS AND WIND CHILL VALUES
WEDNESDAY MORNING MAY VARY FROM PLACE TO PLAY, THE OVERALL MESSAGE
REGARDING THE DANGEROUSLY COLD TEMPERATURES REMAINS VALID.
AS OF NOW, IT APPEARS THAT A VERY SLIGHT WARM UP COULD OCCUR FOR THE
END OF THE WEEK. BY LATER ON WEDNESDAY, THE SURFACE HIGH WILL MOVE
TO THE EAST, WITH FLOW OVER THE OHIO VALLEY TURNING TO THE SOUTH. A
STRONGER SIGNAL FOR WARM ADVECTION IS SHOWING UP FOR THURSDAY, WHEN
TEMPERATURES SHOULD BE ABLE TO GET BACK INTO THE 20S AND 30S.
FINALLY, AS ANOTHER TROUGH MOVES THROUGH THE REGION NEAR THE END OF
THE WEEK, A SLIGHT CHANCE OF SNOW HAS BEEN INTRODUCED TO THE
FORECAST FOR FRIDAY.
AVIATION /12Z SUNDAY THROUGH THURSDAY/
MVFR CIGS REMAIN BLANKETED ACROSS THE REGION AND EXPECT THIS TO
REMAIN THE CASE THROUGH THE MAJORITY, IF NOT ALL, OF THE TAF
PERIOD. THERE IS AN INDICATION FOR SOME CLEARING AND LIFTING TO
VFR TOWARD 06Z MONDAY AND BEYOND, WHICH WILL MOVE IN FROM THE
W, ALLOWING FOR SCATTERING OUT OF CLOUDS PROGRESSIVELY BETWEEN
06Z-12Z.
THE MAIN ITEM OF INTEREST THROUGH THE TAF PERIOD IS GOING TO BE
THE SN, THE FIRST OPPORTUNITY OF WHICH WILL PIVOT N INTO FAR
SRN STRETCHES OF THE AREA THROUGH 18Z. RIGHT NOW, MOST OF THIS
SHOULD MISS THE LOCAL TAF SITES TO THE S, EXCEPT FOR KCVG/KLUK,
WHERE A VCSH HAS BEEN MAINTAINED THROUGH 16Z. EVEN THESE SITES
SHOULD BE ON THE NRN FRINGE OF THE STEADIEST/MOST WIDESPREAD
SN, SO THERE IS NOT A TON OF CONFIDENCE REGARDING VSBYS GIVEN
THEY SHOULD BE VERY CLOSE TO THE NRN EDGE OF THE SN BAND DURING
THIS STRETCH. BUT THERE IS SOME SIGNAL THAT KCVG/KLUK MAY ONLY
SEE A FEW FLURRIES THROUGH THE MORNING OPPOSED TO SN THAT
PRODUCES MVFR/IFR VSBYS.
AFTER THE BANDED SN PIVOTS E PAST 18Z, THE MAIN ITEM OF INTEREST
IS GOING TO BE THE DEVELOPMENT OF SCATTERED TO NUMEROUS SHSN,
INCLUDING POSSIBLE SN SQUALLS, FROM 18Z THROUGH 02Z. THIS
ACTIVITY WILL PROGRESS W TO E THROUGH THE AFTERNOON INTO EARLY
EVENING, POTENTIALLY IMPACTING ANYWHERE WITH BRIEF SQUALL
CONDITIONS OF SUDDEN REDUCTIONS IN VSBYS AND GUSTY WINDS. THE
IMPACT WOULD LIKELY BE FAIRLY BRIEF IN NATURE, BUT POTENTIALLY
SOMEWHAT INTENSE. HAVE INCLUDED A BROAD-BRUSHED VCSH FOR NOW
GIVEN UNCERTAINTIES REGARDING SPECIFIC TIMING FOR ANY ONE
LOCATION.
STEADY N WINDS ON THE ORDER OF 10-12KTS WILL GO MORE OUT OF THE
NW AT 15-18KTS, WITH GUSTS TO AROUND 25KTS, WITH THE ARRIVAL OF
THE ARCTIC FRONT (20Z-00Z FROM W TO E). WINDS WILL SUBSIDE
SUBTLY TOWARD 06Z AND BEYOND, GOING MORE OUT OF THE WNW AT
AROUND 10-12KTS.
OUTLOOK...MVFR CEILINGS MAY LINGER INTO EARLY MONDAY MORNING.
ILN WATCHES/WARNINGS/ADVISORIES
OH...COLD WEATHER ADVISORY FROM 1 AM MONDAY TO 10 AM EST WEDNESDAY
FOR OHZ026-034-035-042>046-051>056-060>065-070>074-
077>082-088.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
OHZ073-074-079-081-082-088.
KY...COLD WEATHER ADVISORY FROM 1 AM MONDAY TO 10 AM EST WEDNESDAY
FOR KYZ089>100.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
KYZ089-090-094>100.
IN...COLD WEATHER ADVISORY FROM 1 AM MONDAY TO 10 AM EST WEDNESDAY
FOR INZ050-058-059-066-073>075-080.
SYNOPSIS...KC
NEAR TERM...KC
SHORT TERM...KC
LONG TERM...HATZOS
AVIATION...KC
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