550
FXUS63 KLMK 082055
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
355 PM EST WED JAN 8 2025
KEY MESSAGES
* BITTERLY COLD TEMPERATURES ARE EXPECTED TONIGHT. A COLD WEATHER
ADVISORY IS IN EFFECT FROM TONIGHT THROUGH THURSDAY MIDMORNING.
* WINTER STORM WATCH REMAINS IN EFFECT FOR ROUGHLY THE SOUTHERN HALF
OF KENTUCKY FOR FRIDAY AND FRIDAY NIGHT.
* FORECAST CONFIDENCE CONTINUES TO INCREASE ON SIGNIFICANT SNOWFALL
FRIDAY AND FRIDAY NIGHT. THE HIGHEST POTENTIAL FOR HEAVY SNOW (4
INCHES OR MORE) ACCUMULATIONS REMAINS ACROSS THE SOUTHERN PART OF
KENTUCKY, MAINLY ALONG AND SOUTH OF THE WESTERN KENTUCKY AND
BLUEGRASS PARKWAYS. NORTH OF THE PARKWAYS, 2-4 INCHES OF SNOW WILL
BE POSSIBLE.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 355 PM EST WED JAN 8 2025
SYNOPSIS...MID-LEVEL SHORTWAVE TROUGH RESPONSIBLE FOR SCATTERED
SNOW SHOWERS TODAY WILL EJECT EASTWARD WHILE WEAK RIDGING MOVES FROM
THE MIDWEST TO THE GREAT LAKES. AT THE SURFACE, ARCTIC HIGH PRESSURE
QUICKLY TRANSITIONS ALONG THE LOWER OHIO VALLEY, BRINGING DRY
WEATHER AND BITTERLY COLD TEMPERATURES TO THE REGION.
MODEL EVALUATION/CONFIDENCE...GREATEST CHALLENGE DURING THE SHORT
TERM WILL BE HOW LOW TEMPERATURES DROP TONIGHT. COMPARED TO PREVIOUS
DAYS, MODELS HAVE GONE UP BY A FEW DEGREES WHICH CAN BE ATTRIBUTED
TO THE CLOUD COVER MANY OF THEM FEATURE OVERNIGHT. THAT BEING SAID,
THE EARLY AFTERNOON VISIBLE SATELLITE IS SHOWING THE MID-LEVEL CLOUD
DECK, ASSOCIATED WITH THE MID-LEVEL WAVE, MOVING TO THE SOUTH AND
EAST PRETTY QUICKLY. THE REMAINING LOW-LEVEL CLOUDS BEHIND THE MID-
LEVEL CLOUD DECK ARE DIURNALLY DRIVEN AND SHOULD DISSIPATE LATER
THIS AFTERNOON AND EARLY EVENING. AS A RESULT, THERE IS INCREASING
CONFIDENCE IN CLEARING SKIES, ESPECIALLY ALONG I-64, WHERE
TEMPERATURES ARE EXPECTED TO FALL NEAR OR BELOW ZERO.
THIS AFTERNOON...EARLIER SCATTERED, LIGHT SNOW SHOWER ACTIVITY HAVE
DECREASED IN COVERAGE AND INTENSITY AND WILL CONTINUE TO DO SO THE
REST OF THIS AFTERNOON. OVERALL, AROUND AN INCH OF SNOW HAS FALLEN
IN ISOLATED LOCATIONS WITH LESSER WIDESPREAD AMOUNTS. ON THE OTHER
HAND, DAYTIME RGB SATELLITE REVEALS LOW-LEVEL CLOUDS FILLING IN
BEHIND THE MID-LEVEL CLOUD DECK DRIVEN BY DIURNAL HEATING AND
PARTIALLY-MELTED SNOWFALL. THEREFORE, THESE LOW-LEVEL CLOUDS SHOULD
DISSIPATE AROUND OR SHORTLY AFTER SUNSET LEADING TO MOSTLY CLEAR
SKIES OVERNIGHT.
TONIGHT...BASED ON CLEARING SKIES, STRONG SUBSIDENCE ACCOMPANYING
THE ARCTIC SURFACE HIGH, AND COOLING EFFECT FROM ONGOING SNOWPACK,
WENT AHEAD AND ISSUE A COLD WEATHER ADVISORY FOR COUNTIES ROUGHLY
ALONG AND NORTH OF I-64. NOT ONLY MINIMUM APPARENT TEMPERATURES WERE
CONSIDERED TO ISSUE THIS HEADLINE, BUT ALSO IMPACTS ON FOLKS WHO ARE
ARE STILL EXPERIENCING POWER OUTAGES. TEMPERATURE WISE, LOWS WILL
RANGE FROM NEAR TO SLIGHTLY BELOW ZERO VALUES IN SOUTHERN INDIANA
AND NORTHERN KENTUCKY TO LOW TEENS IN SOUTH CENTRAL KENTUCKY. ASIDE
FROM THE BITTERLY COLD TEMPERATURES, THERE IS A LOW CHANCE OF
ISOLATED AND SHALLOW FREEZING FOG ALONG RIVERS AND AREAS THAT HAVE
LOST THE SNOW COVER WHERE MOISTURE WILL BE READILY AVAILABLE.
THURSDAY...EXPECT A LOW TEMPERATURE RECOVERY DURING THE MORNING WITH
SINGLE-DIGIT VALUES IN THE NORTHERN HALF OF THE FORECAST AREA
LINGERING CLOSE TO LUNCH TIME. DRY WEATHER AND LIGHT WINDS WILL
PREDOMINATE WITH DIRECT SOLAR RADIATION STARTING TO SUBSTANTIALLY
MELT THE SNOWPACK.
LONG TERM /THURSDAY THROUGH WEDNESDAY/
ISSUED AT 355 PM EST WED JAN 8 2025
==============================================================
* SIGNIFICANT SNOWFALL EXPECTED FRIDAY AND FRIDAY NIGHT
* WINTER STORM WATCH REMAINS IN EFFECT FOR THE SOUTHERN HALF OF
KENTUCKY
==============================================================
THURSDAY NIGHT...
THURSDAY NIGHT IS THE CALM BEFORE THE NEXT STORM. CONDITIONS WILL BE
DRY AND COLD WITH BRIEF RIDGING IN PLACE. HIGH PRESSURE SLIDES OFF
TO THE EAST, AND MID/HIGH CLOUDS QUICKLY INCREASE IN COVERAGE FROM
THE WSW. LOWS WILL OCCUR EARLIER IN THE NIGHT THAN USUAL, WITH
READINGS IN THE 10-20 DEGREE RANGE. HOWEVER, A COUPLE OF OUR TYPICAL
COOL SPOTS IN THE NORTHERN BLUEGRASS COULD DIP INTO THE SINGLE
DIGITS. TO THE SW, TEMPS COULD STABILIZE IN THE LOW/MID 20S DUE TO
INCREASING CLOUD COVER.
FRIDAY THROUGH SATURDAY...
BOTTOM LINE UP FRONT: CONFIDENCE REMAINS HIGH IN IMPACTFUL
ACCUMULATING SNOWS FRIDAY INTO SATURDAY MORNING. IN GENERAL, A
WIDESPREAD AND RELATIVELY UNIFORM 2-5 INCHES OF SNOW ACCUMULATION IS
ANTICIPATED FRIDAY MORNING THROUGH SATURDAY MORNING. THE HIGHER SNOW
AMOUNTS (4-5+ INCHES) IN THAT RANGE ARE MOST LIKELY ACROSS SOUTH-
CENTRAL KENTUCKY, WITH SOMEWHAT LOWER (2-4 INCHES) SNOW AMOUNTS
ACROSS SOUTHERN INDIANA AND NORTH-CENTRAL KENTUCKY. IT IS WORTH
NOTING LOCALIZED SNOW TOTALS APPROACHING 6 INCHES WILL BE POSSIBLE
ACROSS SOUTH-CENTRAL KY.
CONFIDENCE IS HIGH IN WIDESPREAD MINOR TO MODERATE IMPACTS DUE TO
SNOW FRIDAY INTO SATURDAY. EXPECT SLICK AND SNOW-COVERED ROADS, MOST
NOTABLY IMPACTING THE FRIDAY EVENING COMMUTE. PLAN FOR HAZARDOUS,
SLOW TRAVEL CONDITIONS FRIDAY AFTERNOON THROUGH FRIDAY NIGHT.
FORECAST CONFIDENCE ALSO REMAINS HIGH IN SNOW AS THE SOLE
PRECIPITATION TYPE.
METEOROLOGICAL DISCUSSION: A FULL-LATITUDE UPPER LEVEL TROUGH WILL
TRANSLATE EASTWARD OVER THE UPPER MIDWEST AND PLAINS ON FRIDAY, WITH
A SHARPENING MID-LEVEL WAVE OVER THE SOUTHERN PLAINS AND OZARKS. AT
THE SURFACE, LOW PRESSURE IS FORECAST TO GRADUALLY DEEPEN AS IT
GENERALLY MOVES EAST ALONG THE GULF COAST.
MID-LEVEL ASCENT WILL BEGIN INCREASING FRIDAY MORNING AHEAD OF THE
APPROACHING TROUGH, BUT PLENTY OF LOW-LEVEL DRY AIR WILL LIMIT
SNOWFALL CHANCES PRIOR TO DAYBREAK. AFTER 12Z, EXPECT SNOW CHANCES
TO INCREASE FROM WEST TO EAST. MODERATE MID-LEVEL FRONTOGENETICAL
ASCENT PEAKS IN INTENSITY FRIDAY AFTERNOON AND EVENING, AND SNOWFALL
COVERAGE AND INTENSITY WILL BE AT ITS PEAK DURING THIS TIME (18Z FRI
- 06Z SAT). QPF HAS NOT CHANGED DRASTICALLY WITH THIS FORECAST
CYCLE. AROUND 0.20-0.40 INCHES (SWE) IS FORECAST, WITH THE HIGHEST
AMOUNTS ACROSS SOUTH-CENTRAL KY. BASED ON A DEEP COLD LAYER, AND
GOOD SATURATION/LIFT WITHIN THE -10 TO -20 C LAYER, SNOWFALL RATIOS
ARE EXPECTED TO AVERAGE BETWEEN 12:1 AND 15:1.
LIGHT TO MODERATE SNOWFALL WILL CONTINUE FRIDAY NIGHT, WITH LIGHT
SNOW TAPERING OFF SATURDAY MORNING. TOTAL SNOWFALL AMOUNTS ARE
LIKELY TO BE BETWEEN 2-4 INCHES ACROSS SOUTHERN INDIANA AND NORTH-
CENTRAL KY. SNOWFALL AMOUNTS OF 3-6 INCHES WILL BE POSSIBLE ACROSS
SOUTH-CENTRAL KENTUCKY. AS FOR THESE SNOWFALL AMOUNTS, FORECAST
CONFIDENCE REMAINS MEDIUM. THE ONE X-FACTOR WILL BE THE POTENTIAL
FOR MESOSCALE BANDED PRECIP, BUT CONFIDENCE REMAINS LOW ON THE
DEVELOPMENT AND PLACEMENT OF ANY ENHANCED SNOWFALL BANDS. BECAUSE
MESOSCALE DETAILS WILL REQUIRE MORE TIME TO FLESH OUT, WILL HOLD OFF
OF ANY CHANGES TO THE WINTER STORM WATCH AT THIS TIME. SOME
LINGERING SPREAD IN SUPER ENSEMBLE DATA/PLUMES SUGGESTS WE CANNOT
RULE OUT ADDING ADDITIONAL COUNTIES TO THE WATCH OR A POSSIBLE
FUTURE WINTER STORM WARNING. ON THE FLIP SIDE, WE CAN ALSO NOT RULE
OUT A POSSIBLE FUTURE WINTER WEATHER ADVISORY FOR SOME AREAS
CURRENTLY INCLUDED IN THE WINTER STORM WATCH. IN SHORT, STILL LIKE
THE OVERALL PLACEMENT OF THE WINTER STORM WATCH.
TEMPERATURES FRIDAY AFTERNOON WILL CREEP UP TO AROUND THE FREEZING
MARK, BEFORE FALLING BACK INTO THE 20S FRIDAY NIGHT. CLOUDS SHOULD
LINGER THROUGH MOST OF SATURDAY, AND TEMPERATURES DO NOT APPEAR
LIKELY TO RISE ABOVE FREEZING. EXPECT HIGHS IN THE UPPER 20S TO
LOWER 30S.
SATURDAY NIGHT - TUESDAY...
THE SECOND HALF OF THE WEEKEND LOOKS QUIET WITH HIGH PRESSURE
BUILDING ACROSS THE REGION. DEPENDING ON CLOUD COVER, TEMPS WILL
LIKELY DROP INTO THE TEENS SATURDAY NIGHT AND SUNDAY MORNING.
TEMPERATURES WILL RECOVER NICELY ON SUNDAY, HOWEVER, THANKS TO A WAA
REGIME WITH DEVELOPING SOUTHERLY FLOW BEHIND THE DEPARTING AREA OF
HIGH PRESSURE. AFTERNOON HIGHS LOOK TO REACH THE MID 30S IN MOST
AREAS.
THE NEXT WAVE OF LOW PRESSURE SLIDES ACROSS THE GREAT LAKES SUNDAY
NIGHT INTO MONDAY. MOISTURE LOOKS LIMITED AT THIS TIME, WITH BETTER
SNOW POTENTIAL WELL TO OUR NORTH. HOWEVER, THERE IS A SLIGHT CHANCE
FOR BRIEF LIGHT SNOW OR FLURRIES. ANOTHER SHOT OF COLD AIR IS LIKELY
BEHIND THIS WAVE FOR MONDAY NIGHT INTO MIDWEEK.
AVIATION /18Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 1243 PM EST WED JAN 8 2025
STRATUS LAYER HAS BEEN MOVING AT A GOOD CLIP TODAY AND AFTER
TRACKING THE CLOUD EDGE APPROACHING SOUTHERN INDIANA, HAVE INDICATED
A MORE OPTIMISTIC FORECAST WITH EARLIER VFR CONDITIONS RETURNING TO
THE TERMINALS. IN ADDITION, LIGHT SNOW SHOWERS WILL DIMINISH IN
INTENSITY AND COVERAGE THIS AFTERNOON AS CLOUDS PUSH TO THE SOUTH
AND EAST. AS A RESULT, LEX/RGA/BWG WILL SEE A FEW MORE HOURS OF
LIGHT SNOW WITH MVFR/IFR VISIBILITY THIS AFTERNOON WHILE HNB AND SDF
WILL CLEAR SHORTLY AFTER TAF BEGINNING TIME. FOR TONIGHT, CLEAR
SKIES AND CALM/VARIABLE WINDS AS SURFACE HIGH PRESSURE MOVES
OVERHEAD.
LMK WATCHES/WARNINGS/ADVISORIES
KY...COLD WEATHER ADVISORY FROM 11 PM EST /10 PM CST/ THIS EVENING
TO 10 AM EST /9 AM CST/ THURSDAY FOR KYZ023-025-030>037-
040>043-049.
WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH SATURDAY
MORNING FOR KYZ026>028-045>048-053>057-061>067-070>078-
081-082.
IN...COLD WEATHER ADVISORY FROM 11 PM EST /10 PM CST/ THIS EVENING
TO 10 AM EST /9 AM CST/ THURSDAY FOR INZ076>079-083-084-
089>092.
SHORT TERM...ALL
LONG TERM...EBW
AVIATION...ALL
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