006
FXUS63 KLMK 172356
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
656 PM EST MON FEB 17 2025
..UPDATED AVIATION DISCUSSION
KEY MESSAGES
* 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
WARNING AND WINTER WEATHER ADVISORY HAVE BEEN ISSUED WITH THIS
FORECAST UPDATE.
* VERY COLD TEMPERATURES ARE EXPECTED AFTER THE MID-WEEK WINTER
STORM.
SHORT TERM /THROUGH WEDNESDAY/
ISSUED AT 342 PM EST MON FEB 17 2025
AFTERNOON SATELLITE AND OBSERVATIONS SHOW PARTLY CLOUDY SKIES ACROSS
THE REGION. MID-HIGH LEVEL CLOUDS WERE STREAMING INTO THE REGION
FROM THE WEST. TEMPERATURES WERE QUITE COLD WITH READINGS IN THE
LOWER 20S ACROSS SOUTHERN IN AND IN THE MID-UPPER 20S ACROSS MUCH OF
NORTHERN KENTUCKY. THE WARMEST SPOTS WERE DOWN IN THE LAKE
CUMBERLAND AREA WHERE READINGS WERE IN THE LOWER 30S. FOR THE
REMAINDER OF AFTERNOON, NO SIGNIFICANT WEATHER IS EXPECTED.
FOR TONIGHT, WE'LL SEE CLOUDS CONTINUE TO INCREASE AND OVERSPREAD
THE REGION WITH CEILINGS BUILDING DOWN WITH TIME. ALOFT A STRONG
JET STREAK WILL BE FOUND FROM THE GREAT LAKES INTO SOUTHERN NEW
ENGLAND. THIS WILL PLACE THE LOWER OHIO VALLEY WITHIN THE RIGHT
ENTRANCE REGION OF THE JET. LATE IN THE NIGHT, THE CAMS HAVE BEEN
SHOWING A PERSISTENT SIGNAL OF LOW TO MID-LEVEL FRONTOGENESIS AND
ISENTROPIC LIFT OVER IL SPREADING EASTWARD WITH TIME. THE FORCING
FROM THE JET STREAM WILL CONTINUE TO TRANSLATE EASTWARD WITH TIME
AND MAY SLIGHTLY OUTPACE THE LOW-MID LEVEL FORCING
(FGEN/ISENTROPIC), BUT ENOUGH OVERLAP MAY EXIST TO PRODUCE SOME VERY
LIGHT QPF OVER SOUTHERN IN AND INTO NORTHERN KY AROUND SUNRISE.
GIVEN THE COLD COLUMN, RATIOS WOULD BE UP AROUND 15-18:1, SO A
DUSTING TO PERHAPS A FEW TENTHS OF AN INCH OF SNOW COULD FALL.
OVERALL FORECAST CONFIDENCE HERE IS A BIT BELOW AVERAGE GIVEN THE
MODEL SPREAD WITH THIS EVENT ALONG WITH THE QUESTION OF HOW MUCH
FORCING WILL BE AVAILABLE. IT IS RECOGNIZED THAT THE TUESDAY
MORNING COMMUTE COULD BE NEGATIVELY IMPACTED FROM A DUSTING TO A FEW
TENTHS OF AN INCH OF SNOW. AFTER COORDINATING WITH SURROUNDING
OFFICES, HAVE DECIDED TO GO WITH A SPECIAL WEATHER STATEMENT TO
COVER THE POSSIBLE IMPACTS. IF A STRONGER SIGNAL APPEARS IN
UPCOMING FORECAST DATASETS, A SHORT FUSED WINTER WEATHER ADVISORY
COULD BE NEEDED FOR PORTIONS OF SOUTHERN IN AND NORTHERN KY TUESDAY
MORNING. LOWS TONIGHT WILL BE IN THE LOWER-MIDDLE TEENS ACROSS
SOUTHERN IN AND NORTHERN KY, WITH SOUTHERN KY SEEING LOWS IN THE
LOWER 20S.
FOR TUESDAY, SCATTERED SNOW FLURRIES ARE EXPECTED ACROSS THE REGION
WHERE SOME WEAK FORCING ALOFT PUSHING THROUGH THE REGION. HIGHS ON
THE DAY WILL RANGE FROM THE LOW-MID 20S OVER SOUTHERN IN AND
NORTHERN KY WITH UPPER 20S TO AROUND 30 ACROSS SOUTHERN KY.
MOVING INTO TUESDAY NIGHT AND WEDNESDAY, AN AMPLIFYING UPPER LEVEL
TROUGH AXIS WILL PUSH EASTWARD TOWARDS THE REGION WHILE AN ARCTIC
LOW-LEVEL THERMAL BOUNDARY WILL PUSH SOUTHWARD. MUCH OF THE REGION
WILL BE WITHIN THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL 120-
130KT JET STREAK. AS THE UPPER TROUGH PUSHES TOWARD THE REGION,
MUCH OF THE MODEL GUIDANCE SHOWS A STRONG INCREASE IN LOW TO MID-
LEVEL FRONTOGENESIS AND ISENTROPIC LIFT. THIS SHOULD RESULT IN A
VERY LARGE BAND OF SNOW TO BE IN PROGRESS ACROSS MO INTO NORTHERN AR
TUESDAY AFTERNOON WHICH WILL SPREAD EASTWARD INTO CENTRAL KY AND
SOUTHERN IN TUESDAY NIGHT THROUGH WEDNESDAY MORNING. AS THE TROUGH
AXIS PUSHES INTO OUR REGION, IT WILL BE WEAKENING AND SOME LOWER
LEVEL DRY AIR WILL PUNCH INTO THE REGION FROM THE NORTH. THIS WILL
RESULT IN A POTENTIALLY SHARP NORTHERN CUTOFF TO SNOW AMOUNTS.
AS OF THIS WRITING, A SWATH OF HEAVY SNOW LOOKS INCREASINGLY LIKELY
ACROSS CENTRAL AND SOUTHERN KY WITH PERHAPS TWO MAXIMA. THE FIRST
MAXIMA MAY BE OVER WESTERN KY IN THE PADUCAH TO HENDERSON AREA WHERE
4-8 INCHES MAY FALL. THE SECOND MAXIMA OF 4-8 INCHES MAY OCCUR OVER
IN FAR EASTERN KY CENTERED OVER NEAR PIKEVILLE. ACROSS THE CENTRAL
PART OF THE LMK CWA A SOLID 3-6 INCHES LOOKS LIKELY WITH LOCALLY
HIGHER AMOUNTS. A SHARP GRADIENT IS EXPECTED AS ONE GETS UP NEAR
THE I-64 CORRIDOR WHERE AMOUNTS WILL DROP OFF INTO THE 2-3 INCH
RANGE.
AFTER COORDINATING WITH SURROUNDING OFFICES AND WPC, HAVE ELECTED TO
UPGRADE THE WINTER STORM WATCH TO A COMBINATION OF WINTER STORM
WARNING AND WINTER WEATHER ADVISORY. THE WINTER STORM WARNING WAS
PLACED ACROSS MUCH OF CENTRAL/SOUTHERN KY IN AREAS SOUTH OF THE I-64
CORRIDOR. THIS IS WHERE THE TOTAL MULTI-MODEL CONSENSUS SHOWED
GREATER THAN A 50% OF EXCEEDING 4 INCHES. TO THE NORTH A WINTER
WEATHER ADVISORY WAS ISSUED. WE STILL MAY SEE SOME FLUCTUATIONS IN
THE MODEL DATA OVER THE NEXT 12-18 HOURS AND SOME FURTHER
REFINEMENTS TO THE HEADLINES MAY BE REQUIRED IN SUBSEQUENT FORECASTS.
THE SNOW WILL BE HEAVIEST FROM LATE TUESDAY EVENING THROUGH ABOUT
SUNRISE WEDNESDAY MORNING. TRAVEL DURING THIS PERIOD WILL BE
DIFFICULT TO PERHAPS IMPOSSIBLE FOR SHORT PERIODS OF TIME AS SNOW
RATES WILL LIKELY OUTPACE THE ABILITY TO KEEP THE ROADS CLEAR.
RESIDENTS OF SOUTHERN IN AND CENTRAL KY SHOULD CONTINUE TO CLOSELY
MONITOR THE FORECAST FOR UPDATES, AND HAVE PLANS TO PREPARE FOR
IMPACTS TO DAILY LIFE.
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
ISSUED AT 342 PM EST MON FEB 17 2025
WEDNESDAY NIGHT...
BY WEDNESDAY EVENING, THE STORM SYSTEM WHICH WILL BRING SNOW TO OUR
AREA TUESDAY NIGHT AND WEDNESDAY MORNING WILL BE EXITING THE
CAROLINAS. THE PRIMARY UPPER LEVEL TROUGH AXIS IS EXPECTED TO PIVOT
THROUGH THE REGION WEDNESDAY NIGHT INTO THURSDAY MORNING, WITH LOW-
LEVEL MOISTURE LINGERING IN THE FORM OF A STRATUS DECK. THE AIR MASS
ALOFT WILL BE COLD ENOUGH THAT THE LOW-LEVEL CLOUD LAYER WILL BE IN
THE DGZ, AND BROAD WEAK UPLIFT IN THE VICINITY OF THE TROUGH WILL
ALLOW FOR SOME SCATTERED FLURRIES AND SNOW SHOWERS TO DEVELOP LATE
WEDNESDAY NIGHT INTO THURSDAY MORNING. OVERALL, A LACK OF DEEP
MOISTURE SHOULD KEEP SNOW AMOUNTS LIGHT, ALTHOUGH SNOW RATIOS IN
EXCESS OF 18:1 MAY ALLOW FOR LOCALIZED SWATHS OF 1/2 INCH OR MORE.
ANY LINGERING SNOW SHOWERS SHOULD WIND DOWN BY MID-MORNING THURSDAY.
* VERY COLD WEATHER LATER THIS WEEK *
CANADIAN SFC HIGH PRESSURE WILL SINK DOWN INTO THE PLAINS STATES ON
THURSDAY, WITH ANTICYCLONIC FLOW PRODUCING CONTINUED NW FLOW AND
COLD ADVECTION ACROSS THE OHIO VALLEY. WHILE WINDS SHOULDN'T BE
PARTICULARLY STRONG ON THURSDAY, PERSISTENT 5-15 MPH WIND SPEEDS
WILL SEND WIND CHILLS TO NEAR OR SLIGHTLY BELOW ZERO THURSDAY
MORNING. THURSDAY INTO THURSDAY NIGHT, THE ECMWF EXTREME FORECAST
INDEX IS -0.9 OR LOWER ACROSS PORTIONS OF THE AREA, INDICATING HIGH
CONFIDENCE IN ANOMALOUSLY COLD TEMPERATURES. INDEED, THE CURRENT
FORECAST ONLY GETS TEMPERATURES INTO THE UPPER TEENS AND LOWER 20S
ON THURSDAY, WITH WIND CHILLS EXPECTED TO REMAIN IN THE HIGH SINGLE
DIGITS AND LOWER TEENS THROUGH THE DAY.
BY THURSDAY NIGHT, WINDS WILL GRADUALLY EASE AS HIGH PRESSURE MOVES
CLOSER TO THE AREA. THURSDAY NIGHT AND FRIDAY MORNING SHOULD FEATURE
THE COLDEST TEMPERATURES OF THE UPCOMING WEEK, WITH EXACTLY HOW COLD
IT GETS STILL DEPENDENT ON THE AMOUNT OF CLEARING AND WHERE DEEPER
SNOW COVER EXISTS. AT THIS TIME, EXPECTING WIDESPREAD LOWS IN THE
LOW-TO-MID SINGLE DIGITS, WITH SPOTS THAT DECOUPLE LIKELY FALLING TO
NEAR OR EVEN SLIGHTLY BELOW ZERO. COLD WEATHER HEADLINES MAY BE
NEEDED FOR PART OR ALL OF THE WEDNESDAY NIGHT THROUGH THURSDAY NIGHT
TIME FRAME.
FRIDAY THROUGH NEXT WEEKEND...
ON FRIDAY, A GRADUAL MODERATION IN TEMPERATURES IS EXPECTED TO BEGIN
AS SFC HIGH PRESSURE MOVES ACROSS THE AREA AND LOW-AMPLITUDE UPPER
RIDGING BEGINS TO MOVE INTO THE MID-MISSISSIPPI VALLEY. WHILE
TEMPERATURES ARE ONLY EXPECTED TO WARM TO AROUND THE FREEZING MARK
FRIDAY AFTERNOON, LIGHT WINDS AND MOSTLY SUNNY SKIES SHOULD HELP
THINGS FEEL WARMER. DRY AND CHILLY CONDITIONS WILL CONTINUE INTO
FRIDAY NIGHT.
FOR NEXT WEEKEND, THERE IS A CONSISTENT SIGNAL IN MEDIUM-RANGE
ENSEMBLE GUIDANCE FOR A WEAK SYSTEM TO MOVE ACROSS THE REGION AHEAD
OF A RELATIVELY WEAK UPPER SHORTWAVE. HOWEVER, IN THE 12Z DATA, THE
ECMWF SOLUTION IS FASTER IN EJECTING THE SYSTEM EASTWARD, BRINGING
LIGHT PRECIPITATION ACROSS THE OHIO VALLEY ON SATURDAY. IN CONTRAST,
THE GFS DELAYS THIS SYSTEM UNTIL SUNDAY. BOTH DEPICTIONS HAVE A
THERMAL PROFILE WHICH WOULD BE SUPPORTIVE FOR WINTRY PRECIPITATION,
WITH THE ECMWF P-TYPE METEOGRAMS SHOWING PREDOMINANTLY SNOW ACROSS
KENTUCKY AND INDIANA. THIS SYSTEM WOULD BE WORKING WITH FAIRLY
SPARSE AMOUNTS OF MOISTURE, WITH THE 12Z CANADIAN SOLUTION ENTIRELY
SUPPRESSING PRECIPITATION. AT THIS TIME, SIGNIFICANT IMPACTS ARE NOT
EXPECTED WITH THIS SYSTEM.
TEMPERATURES WILL CONTINUE TO MODERATE THROUGH THE WEEKEND AS RETURN
FLOW BEGINS TO WORK INTO THE REGION FROM THE SOUTHWEST. BY LATE
WEEKEND, TEMPERATURES SHOULD RETURN TO NEAR CLIMATOLOGICAL NORMALS,
ALTHOUGH THIS IS DEPENDENT ON WHAT HAPPENS WITH THE ABOVE-MENTIONED
SYSTEM.
AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 655 PM EST MON FEB 17 2025
PRIMARILY MID LEVEL CLOUDS EXPECTED OVERNIGHT, WITH CEILINGS
GRADUALLY LOWERING EARLY TUE MORNING. A NARROW BAND OF LIGHT SNOW
COULD IMPACT THE NORTHERN (I-64) TERMINALS BETWEEN ~09-16Z, AND
BRIEF MVFR VIS WILL BE POSSIBLE. CEILINGS ARE LIKELY TO DROP TO MVFR
BY 09-13Z TUE, WITH SOME BRIEF IMPROVEMENT TO VFR POSSIBLE AFTER 19-
20Z. CEILINGS WILL THEN QUICKLY DETERIORATE ONCE AGAIN BEYOND 19.00Z
IN THE SDF PLANNING PERIOD AS MORE WIDESPREAD MODERATE SNOW SPREADS
INTO THE REGION FROM THE WEST. A WINTER STORM WILL BRING SIGNIFICANT
SNOW ACCUMULATION TO CENTRAL AND SOUTHERN KY, ESPECIALLY SOUTH OF I-
64, TUESDAY NIGHT. AT THIS TIME, 2-3 INCHES OF SNOW LOOKS POSSIBLE
AT SDF/HNB THROUGH WEDNESDAY AFTERNOON. 3-5 INCHES OF SNOW IS
EXPECTED AT LEX/RGA/BWG. THE HEAVIEST SNOWFALL RATES ARE
CURRENTLY EXPECTED BETWEEN 03-12Z WEDNESDAY.
LMK WATCHES/WARNINGS/ADVISORIES
KY...WINTER WEATHER ADVISORY FROM 7 PM TUESDAY TO NOON EST
WEDNESDAY FOR KYZ030>037-042-043.
WINTER STORM WARNING FROM 7 PM EST /6 PM CST/ TUESDAY TO NOON
EST /11 AM CST/ WEDNESDAY FOR KYZ023>029-038>041-045>049-
053>057-061>067-070>078-081-082.
IN...WINTER WEATHER ADVISORY FROM 7 PM TUESDAY TO NOON EST
WEDNESDAY FOR INZ076>079-083-084-090>092.
WINTER STORM WARNING FROM 6 PM TUESDAY TO 11 AM CST WEDNESDAY
FOR INZ089.
SHORT TERM...MJ
LONG TERM...CSG
AVIATION...EBW
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