483
FXUS63 KLMK 171722
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1222 PM EST MON FEB 17 2025
..UPDATED AVIATION DISCUSSION
KEY MESSAGES
* COLD TEMPERATURES EARLY THIS MORNING HAVE FROZEN LINGERING WET
SURFACES. AREAS OF BLACK ICE ARE POSSIBLE FOR THE MORNING COMMUTE.
* A SKIFF OF LIGHT SNOW IS EXPECTED TUESDAY MORNING. A DUSTING TO A
HALF AN INCH OF ACCUMULATION IS MOST LIKELY IN A TRIANGLE BETWEEN
JASPER, IN, THE LOUISVILLE METRO, AND HARTFORD, KY. FLURRIES
EXPECTED ELSEWHERE.
* AN IMPACTFUL WINTER STORM IS FORECAST TO BRING SNOW ACCUMULATIONS
FOR TUESDAY NIGHT THROUGH WEDNESDAY AFTERNOON. A WINTER STORM
WATCH REMAINS IN EFFECT FOR ALL OF SOUTHERN INDIANA AND CENTRAL
KENTUCKY.
* VERY COLD TEMPERATURES ARE EXPECTED AFTER THE MID-WEEK WINTER
STORM.
UPDATE
ISSUED AT 1053 AM EST MON FEB 17 2025
MORNING SATELLITE AND OBSERVATIONS SHOW PARTLY CLOUDY SKIES ACROSS
THE REGION. MORNING TEMPERATURES WERE IN THE UPPER TEENS TO THE
LOWER 20S ALONG AND NORTH OF THE WK/BG PARKWAYS. ACROSS THE SOUTH
WHERE LOW CLOUDS HUNG IN OVERNIGHT, TEMPS WERE GENERALLY IN THE MID
20S. SHOULD CONTINUE TO SEE THIS LOW CLOUD LAYER BREAK UP A BIT AND
SCOUR OUT LATER THIS MORNING AND INTO THE AFTERNOON. AFTERNOON
HIGHS IN THE LOWER-MID 20S ACROSS SOUTHERN IN AND THE NORTHERN HALF
OF KY LOOK GOOD, WITH UPPER 20S/LOWER 30S ACROSS SOUTHERN KY.
ON THE HYDROLOGY SIDE, AFTER COORDINATING WITH WFO JKL, WE HAVE GONE
AHEAD AND DROPPED OUR AREAL FLOOD WARNINGS ACROSS THE CWA. WATER
CONTINUES TO RECEDE IN OUR COUNTIES WITH FLOODING LARGELY CONFINED
TO THE RIVER BASINS, THOUGH SOME ROADS IN LOW SPOTS MAY CONTINUE TO
BE FLOODED FOR A LITTLE WHILE LONGER.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 336 AM EST MON FEB 17 2025
THINGS ARE FAIRLY QUIET EARLY THIS MORNING, ALTHOUGH A COUPLE OF
THINGS WORTH NOTING OFF THE BAT. THE LINGERING STRATUS DECK, MOSTLY
ALONG AND SOUTH OF THE OHIO RIVER NOW, IS CONTINUING TO MAKE SLOW
PROGRESS. STILL SEEING SOME FLURRIES WITH THESE CLOUDS, SO HAVE
EXTENDED THE RESIDENCE TIME OF THAT OVER MUCH OF THE EASTERN HALF OF
THE CWA TO ACCOUNT FOR THAT. STILL EXPECT OVERALL IMPROVEMENT BY MID
TO LATE MORNING WITH SOME PARTIAL SUNSHINE MID TO LATE MORNING
THROUGH EARLY TO MID AFTERNOON. THE SUNSHINE WILL HELP A LITTLE, BUT
TEMPERATURES ARE STILL GOING TO STRUGGLE UNDER A STEADY COLD
ADVECTION COMPONENT AND A FAIRLY FRESH SNOWPACK. LOOKING FOR HIGHS
ONLY IN THE UPPER 20S TO AROUND 30 ACROSS SOUTHERN IN AND NORTHERN
KY, AND MAY SQUEEZE INTO THE LOW AND MID 30S ACROSS SOUTHERN KY.
WE'LL SEE INCREASING UPPER SKY COVER BY LATE AFTERNOON THROUGH THE
EVENING, AND CLOUD CEILINGS SHOULD STEADILY LOWER INTO TONIGHT.
THERE HAS BEEN A CONSISTENT SIGNAL FOR A SKIFF OF SNOW STARTING IN
THE PRE-DAWN HOURS ACROSS OUR WEST CENTRAL TO NW CWA, AND LASTING
INTO TUESDAY MORNING. WE'LL SEE A PERIOD OF SOME WEAK LOW TO MID
LEVEL FRONTOGENESIS BENEATH THE FAVORABLE RIGHT ENTRANCE REGION OF
AN UPPER JET. SATURATION IS CO-LOCATED WITH TEMPS AT LEAST TO -10C,
AND GIVEN OUR SURFACE TEMPS IN THE TEENS TO AROUND 20, SNOW RATIOS
ARE EXPECTED TO BE QUITE HIGH. LOOKING FOR THEM TO BE IN THE 15 TO
18:1 RATIO, AND WITH ROUGHLY .02" TO .03" OF FORECAST QPF THINK THAT
A DUSTING TO A HALF AN INCH OF SNOW SEEMS PRETTY REASONABLE. THAT
RANGE SHOULD APPLY TO A TRIANGLE BETWEEN JASPER, IN TO LOUISVILLE,
KY TO HARTFORD, KY. OUTSIDE OF THAT AREA, WILL CARRY JUST FLURRY
MENTION FOR A GOOD CHUNK OF SOUTHERN IN AND NORTHERN KY.
LONG TERM /TUESDAY THROUGH SUNDAY/
ISSUED AT 336 AM EST MON FEB 17 2025
===== TUESDAY =====
UPPER LEVEL FLOW WILL BE MOSTLY ZONAL FOR THE START OF THE LONG TERM
PERIOD, THOUGH A WEAK DISTURBANCE RIDING IN THE FLOW, COMBINED WITH
RIGHT ENTRANCE REGION JET DYNAMICS, COULD PRODUCE SOME LIGHT SNOW
ACROSS PORTIONS OF SOUTHERN INDIANA AND NORTH-CENTRAL KENTUCKY
DURING THE MORNING HOURS. TEMPERATURES WILL START OUT IN THE TEENS
AND LOW 20S, WHICH WILL HELP KEEP ANY PRECIP AS SNOW. SNOW AMOUNTS
UP TO HALF AN INCH ARE EXPECTED TUESDAY MORNING WITH THIS WEAK
DISTURBANCE. HIGH TEMPS FOR THE DAY WILL VARY QUITE A BIT FROM NORTH
TO SOUTH ACROSS THE FORECAST AREA, WITH NORTH-CENTRAL KENTUCKY AND
SOUTHERN INDIANA COUNTIES STAYING IN THE 20S, BUT SOUTH-CENTRAL
KENTUCKY LIKELY GETTING ABOVE FREEZING AND IN THE MID-30S.
TUESDAY NIGHT THROUGH SUNDAY...
* IMPACTFUL WINTER STORM EXPECTED TUESDAY NIGHT *
* WINTER STORM WATCH REMAINS IN EFFECT *
THE PRIMARY FOCUS OF THE LONG TERM PERIOD CONTINUES TO BE ON THE
STORM SYSTEM SET TO BRING IMPACTFUL SNOW AMOUNTS TO THE AREA FOR
TUESDAY NIGHT AND INTO WEDNESDAY. AN AMPLIFYING MID-LEVEL TROUGH
OVER THE GREAT PLAINS WILL SWEEP ACROSS THE CENTRAL US, LEADING TO
AN INCREASE IN SYNOPTIC SCALE FORCING OVER THE REGION. WE'LL SEE AN
INCREASE IN 850-700 MB WAA AND ISENTROPIC LIFT SPREAD OVER THE AREA
TUESDAY NIGHT AS A SFC LOW DEVELOPS ALONG THE GULF COAST. COMBINED
WITH UPPER LEVEL DIVERGENCE WITHIN THE FAVORED RIGHT ENTRANCE REGION
OF A 120KT UPPER LEVEL JET STREAK, LOW LEVEL CONVERGENCE AND
STRENGTHENING FGEN AND VERTICAL VELOCITIES WILL SUPPORT WIDESPREAD
MODERATE TO LOCALLY HEAVY SNOWFALL IN THE FORECAST AREA. DESPITE THE
LOW-MID LEVEL WAA, OUR COLUMN IS EXPECTED TO BE COLD ENOUGH FOR THIS
EVENT TO SUPPORT ALL SNOW P-TYPE.
SNOWFALL AMOUNTS HAVE DECREASED SLIGHTLY WITH THIS MONDAY MORNING
FORECAST PACKAGE, BUT THERE REMAINS SOME CONSIDERABLE SPREAD IN
ENSEMBLES, AS EVIDENT IN THE BOX AND WHISKER PLOTS. THE NBM, FOR
EXAMPLE, HAS A 24-HOUR SNOWFALL SPREAD BETWEEN 1-10 INCHES, WITH A
MEAN OF AROUND 3-4 INCHES FOR THE AREA. WITH SUCH SPREAD, CONFIDENCE
IN SNOWFALL AMOUNTS REMAINS SOMEWHAT LIMITED AT THIS TIME. THE GEFS
AND EPS ENSEMBLES HAVE COME DOWN IN SNOW AMOUNTS SINCE THE 12Z
SUITE, WHICH HAS LOWERED LREF SNOW PROBABILITIES. WHAT IS CONSISTENT
IS THE AXIS OF EXPECTED HEAVIEST SNOW, WHICH IS EXPECTED TO SET UP
ACROSS SOUTHERN MISSOURI AND EXTEND EASTWARD INTO PORTIONS OF
SOUTHERN ILLINOIS AND WESTERN KENTUCKY. THIS CORRESPONDS WELL WITH
THE WPC WSSI-P FOR HIGHEST PROBABILITIES OF MODERATE WINTER IMPACTS.
WHILE A MIX OF MINOR AND MODERATE IMPACTS ARE POSSIBLE ACROSS OUR
AREA, THE GREATER IMPACTS ARE MOST LIKELY IN THE WESTERN HALF OF THE
COMMONWEALTH.
SNOW TO LIQUID RATIOS ARE EXPECTED TO BE FAIRLY HIGH, WITH 13:1 TO
17:1 NORTH OF THE PARKWAYS, AND A MORE MODEST 10:1 TO 13:1 ACROSS
SOUTH-CENTRAL KENTUCKY. WPC 24-HOUR SNOW PROB GUIDANCE GIVES GOOD
INDICATIONS OF THE SNOW AMOUNTS POSSIBLE. THE HIGH SNOW CHANCES
APPEAR TO FOCUS ON CENTRAL KENTUCKY, BETWEEN I-64 AND THE CUMBERLAND
PARKWAY. THIS STILL AGREES QUITE WELL WITH THE PREVIOUS FORECAST,
WHICH MENTIONED ELIZABETHTOWN TO RICHMOND. IN THIS SPECIFIC AREA,
THERE IS AN 82% CHANCE OF EXCEEDING 2 INCHES IN 24 HOURS.
ADDITIONALLY, THERE IS A ROUGHLY 40% CHANCE OF EXCEEDING 4 INCHES,
AND 5-10% OF EXCEEDING 6 INCHES OF SNOW. WHILE CONFIDENCE IS NOT
HIGH ENOUGH TO UPGRADE TO A WINTER STORM WARNING WITH THIS FORECAST
PACKAGE, WILL CONTINUE WITH THE WINTER STORM WATCH AT THIS TIME. AN
UPGRADE TO AT LEAST A WINTER WEATHER ADVISORY WILL BE NEEDED IN A
FUTURE FORECAST PACKAGE.
MUCH OF THIS SNOW WILL FALL FROM MID-LATE EVENING TUESDAY THROUGH
WEDNESDAY AFTERNOON WITH THINGS DIMINISHING WEDNESDAY EVENING.
CONTINUE TO MONITOR FOR FORECAST UPDATES, AND HAVE PLANS IN PLACE TO
PREPARE FOR IMPACTS TO DAILY LIFE.
* VERY COLD WEATHER LATER THIS WEEK *
IN THE WAKE OF SNOW, VERY COLD AIR WILL TAKE HOLD ACROSS THE AREA
FOR THE REST OF THE WEEK. TEMPS FOR WEDNESDAY NIGHT INTO THURSDAY
MORNING ARE FORECAST TO DROP TO SINGLE DIGITS, WITH WIND CHILLS NEAR
OR JUST BELOW ZERO. WITH SUCH A COLD START TO THURSDAY, TEMPS WILL
HAVE A DIFFICULT TIME RECOVERING. HIGHS FOR THE DAY WILL STRUGGLE
GET OUT OF THE TEENS AND LOW 20S. HIGHS FRIDAY MAY STRUGGLE AGAIN TO
GET INTO THE MID-UPPER TEENS, WITH LOWS SATURDAY MORNING DROPPING
BACK INTO THE LOW SINGLE DIGITS. SOME MODERATION IN TEMPS IS
POSSIBLE THIS WEEKEND.
AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 1221 PM EST MON FEB 17 2025
MVFR STRATUS DECK CONTINUES TO SCOUR OUT ACROSS THE REGION. KBWG
MAY HOLD ON TO MVFR CIGS FOR ANOTHER COUPLE OF HOURS OR SO.
ELSEWHERE, VFR CONDITIONS WITH MAINLY WEST-NORTHWEST WINDS OF 5-8KTS
WILL BE SEEN THIS AFTERNOON WITH UPPER LEVEL CLOUD COVER INCREASING
LATE IN THE DAY. LATER TONIGHT, CIGS WILL GRADUALLY LOWER AFTER
MIDNIGHT WITH SOME LIGHT SNOW DEVELOPING AT KHNB/KSDF. SOME
FLURRIES WILL BE POSSIBLE OVER AT KLEX/KRGA. WINDS WILL SHIFT TO
THE NORTH TONIGHT AND THEN VEER TO THE NORTHEAST LATE TONIGHT INTO
TUESDAY MORNING.
LMK WATCHES/WARNINGS/ADVISORIES
KY...WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
EVENING FOR KYZ023>043-045>049-053>057-061>067-070>078-
081-082.
IN...WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
EVENING FOR INZ076>079-083-084-089>092.
UPDATE.......MJ
SHORT TERM...BJS
LONG TERM....CJP
AVIATION.....MJ
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