321
FXUS63 KLMK 091717
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1217 PM EST THU JAN 9 2025
..UPDATED AVIATION DISCUSSION
KEY MESSAGES
* A SIGNIFICANT WINTER STORM WILL AFFECT THE REGION ON FRIDAY AND
FRIDAY NIGHT. WIDESPREAD SNOWFALL ACCUMULATIONS OF 3-6 INCHES
WITH LOCALLY HIGHER AMOUNTS ACROSS FAR SOUTHERN KY ARE EXPECTED.
* A WINTER STORM WARNING HAS BEEN ISSUED FOR THE ENTIRE LMK
FORECAST AREA WITH THIS FORECAST ISSUANCE.
UPDATE
ISSUED AT 941 AM EST THU JAN 9 2025
QUIET MORNING ACROSS SOUTHERN INDIANA AND CENTRAL KENTUCKY WITH
SURFACE OBSERVATIONS REPORTING WARMING TEMPERATURES INTO THE LOW
TEENS AND IMPROVING VISIBILITIES WHERE LIGHT/DENSE FREEZING FOG WAS
REPORTED AT SUNRISE, ALTHOUGH THERE ARE STILL A FEW POCKETS OF FOG
AND SINGLE-DIGIT TEMPERATURE READINGS IN RURAL AREAS. AS A RESULT,
THE COLD WEATHER AND FREEZING FOG ADVISORIES WERE CANCELLED. REST OF
THE FORECAST REMAINS ON TRACK WITH BELOW-FREEZING HIGHS AND SUNNY
CONDITIONS THIS AFTERNOON.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 337 AM EST THU JAN 9 2025
THE COMBINATION OF CLEAR SKIES, CURRENT SNOWPACK AND LIGHT WINDS
HAVE ALLOWED TEMPERATURES ACROSS THE AREA TO DROP INTO THE SINGLE
DIGITS AND LOW TEENS SO FAR THIS EARLY MORNING. NIGHTTIME
MICROPHYSICS SATELLITE IMAGERY CONTINUES TO SHOW AN AREA OF STRATOCU
OVER THE SOUTHWESTERN CWA. WHERE THE CLOUDS HAVE LINGERED SO FAR
OVERNIGHT TEMPERATURES WERE IN THE UPPER TEENS TO RIGHT AROUND 20
DEGREES PER THE KENTUCKY MESONET. WHERE SKIES HAVE CLEARED, THE
CONCERN HAS BEEN THE POTENTIAL FOR FREEZING FOG IN THE PRE-DAWN
HOURS. SO FAR THIS EVENING, OTHER THAN A COUPLE OF ISOLATED
LOCATIONS, VISIBILITIES HAVEN'T DROPPED MUCH BELOW 5 SM. WITH THIS
BEING SAID, MODELS CONTINUE TO AGGRESSIVELY HIT HARD AT THE
DEVELOPMENT OF DENSE FOG IN AREAS THE CLEARED RIGHT BEFORE SUNSET
YESTERDAY EVENING. MODELS SEEM TO AGREE THAT THE BEST TIMING FOR FOG
DEVELOPMENT SEEMS TO BE BETWEEN 10-14Z. WHILE MODELS SEEM BULLISH IN
DEVELOPING FOG. WITH DRY DEW POINTS IN THE SINGLE DIGITS AND NOW
ADDITIONAL MOISTURE WORKING OVER THE COLD SNOWPACK, CONFIDENCE IS
STILL A LITTLE LOW ON THE FOG DEVELOPMENT. THE OTHER POTENTIAL
CHALLENGE WILL BE LOW TEMPERATURES FOR AREAS THAT ARE STILL UNDER
LOW STRATOCU EARLY THIS MORNING. DECIDED TO INCREASE THOSE UP A
LITTLE GIVEN HOW SLOW THE CURRENT CLOUD COVER HAS BEEN TO WORK OUT
OF THE AREA.
SFC HIGH PRESSURE ALONG WITH UPPER RIDGING WILL BUILD OVER THE
REGION TODAY. ANY FOG THAT FORMS IS EXPECTED TO MIX OUT BY MID
MORNING GIVING WAY TO MOSTLY SUNNY SKIES. WINDS WILL REMAIN LIGHT
AND TEMPERATURES REBOUNDING INTO THE MID/UPPER 20S WITH LOW 30S
ACROSS OUR SOUTHERN TIER OF COUNTIES NEAR THE TN/KY BORDER.
AS HIGH PRESSURE PUSHES EASTWARD TONIGHT, ALONG WITH THE UPPER
RIDGE, CLOUDS WILL BE ON THE INCREASE THANKS TO ISENTROPIC LIFT
AHEAD OF THE NEXT APPROACHING SYSTEM. OVERNIGHT LOWS WILL RANGE FROM
THE LOW TEENS TO EVEN SINGLE DIGITS ACROSS THE BLUE GRASS WHERE
SKIES SHOULD REMAIN CLEAR LONGER WHILE OFF TO THE WEST AND
SOUTHWEST, LOWS WILL BE IN THE MID/UPPER TEENS TO EVEN LOW 20S
ACROSS THE SOUTHWEST WHERE CLOUD COVER WILL BE OVER THE AREA LONGER.
SLIGHT CHANCE POPS START TO WORK IN FROM THE WEST AS THE NEXT SYSTEM
APPROACHES. WITH DEW POINTS IN THE TEENS, ANY EARLY ONSET OF SNOW
WILL LIKELY FALL AS VIRGA OR FLURRIES FROM THE WEST/SOUTHWEST
TOWARDS THE END OF THE SHORT TERM.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
ISSUED AT 337 AM EST THU JAN 9 2025
==============================================================
* WINTER STORM TO AFFECT THE REGION FRIDAY AND FRIDAY NIGHT
* WINTER STORM WATCH UPGRADED TO WINTER STORM WARNING
==============================================================
FRIDAY THROUGH SATURDAY NIGHT...
AN IMPACTFUL WINTER STORM WILL MOVE THROUGH THE REGION FRIDAY AND
FRIDAY NIGHT BRINGING SIGNIFICANT SNOWS TO THE REGION. FORECAST
CONFIDENCE IN THE EVENT REMAINS HIGH, AND FORECAST CONFIDENCE ON
SNOWFALL AMOUNTS CONTINUES TO INCREASE.
SYNOPTICALLY, A FULL LATITUDE UPPER TROUGH AXIS WILL MOVE FROM THE
PLAINS EASTWARD INTO THE OHIO VALLEY ON FRIDAY. A SHARPENING UPPER
TROUGH IN THE SOUTHERN STREAM WILL ALLOW SURFACE CYCLOGENESIS TO
TAKE PLACE WITH A SURFACE LOW MOVING ALONG THE NORTHERN GULF COAST.
PLENTIFUL MOISTURE WILL BE ADVECTED NORTHWARD INTO THE TN AND OH
VALLEYS AND WITH PLENTIFUL DEEP/COLD AIRMASS IN PLACE, SNOW WILL BE
THE COMMON PRECIPITATION TYPE WITH THIS EVENT.
WARM ADVECTION PRECIPITATION PRODUCTION WILL BE IN FULL SWING FRIDAY
MORNING ACROSS THE OZARKS AND INTO SE MO/W TN/W KY WITH SNOW
ADVANCING NORTHEASTWARD. MODEL SOUNDINGS DO SHOW AN INITIAL DRY
ATMOSPHERE OVER MUCH OF CENTRAL/EASTERN KY, BUT THE COLUMN IS
EXPECTED TO MOISTEN UP QUICKLY WITH SNOW ADVANCING EASTWARD TOWARD
THE I-65 CORRIDOR BY MID-MORNING AND OVERSPREADING INTO THE I-75
CORRIDOR DURING THE EARLY AFTERNOON. MODEL TIME-HEIGHT CROSS
SECTIONS CONTINUE TO SHOW A COUPLE OF AREAS OF STRONGER
FRONTOGENETICAL FORCING. ONE WILL BE FROM CENTRAL AR NORTHEAST
INTO WESTERN/CENTRAL TN AND SOUTHERN KY. ANOTHER BAND MAY DEVELOP
ALONG THE MS/OH RIVER CONFLUENCE NORTHEASTWARD ALONG THE OHIO RIVER.
ADDITIONALLY, SYNOPTIC SCALE LIFT WILL BE ENHANCED AS WE'LL BE
LOCATED IN THE RIGHT ENTRANCE REGION OF AN ANTICYCLONICALLY CURVED
JET COMING OUT OF THE NE US INTO THE WESTERN ATLANTIC, WHILE ALSO
BEING SUPERIMPOSED IN THE LEFT EXIT REGION OF A CYCLONICALLY CURVED
JET AXIS COMING OUT OF TX AND THE DEEP SOUTH. THESE FEATURES SHOULD
RESULT IN PERIODS OF MODERATE TO OCCASIONALLY HEAVY SNOWFALL ACROSS
MUCH OF THE LMK COUNTY WARNING AREA. THIS MODERATE TO HEAVY
SNOWFALL WILL PRIMARILY BE FOCUSED IN THE FRIDAY AFTERNOON/FRIDAY
EVENING TIME PERIOD. LOCALLY HEAVIER BANDED PRECIPITATION ALONG THE
FRONTOGENETICAL AREAS MENTIONED ABOVE WILL BE POSSIBLE. HOWEVER,
THERE REMAINS SOME UNCERTAINTY ON HOW THESE BANDS WILL DEVELOP,
ESPECIALLY AT THIS TIME RANGE.
IN TERMS OF SNOWFALL ACCUMULATION, THE MULTI-MODEL CONSENSUS
CONTINUES TO FAVOR THE SOUTHERN HALF OF KENTUCKY WITH THE HIGHEST
SNOWFALL AMOUNTS, WITH SLIGHTLY LESSER AMOUNTS ACROSS SOUTHERN
INDIANA AND NORTHERN KENTUCKY. IN GENERAL, A 3-6 INCH SNOWFALL IS
EXPECTED FROM SOUTHERN INDIANA DOWN INTO SOUTHERN KENTUCKY. ACROSS
THE SOUTHERN PART OF KENTUCKY 4-7 INCHES WILL BE POSSIBLE. SINCE
THE ENSEMBLE MEAN IS AT 4 INCHES ACROSS MUCH OF THE REGION, WE WILL
GO AHEAD AND UPGRADE THE ENTIRE CWA TO A WINTER STORM WARNING WITH
THIS PACKAGE.
THE SNOW WILL DIMINISH RAPIDLY FROM WEST TO EAST LATE FRIDAY NIGHT
WITH CLOUDY SKIES AND SCATTERED SNOW FLURRIES CONTINUING INTO THE
DAY ON SATURDAY. HIGHS FRIDAY WILL BE IN THE UPPER 20S TO NEAR
FREEZING, WITH LOWS FRIDAY NIGHT DROPPING INTO THE UPPER TEENS AND
LOWER 20S. HIGHS SATURDAY WILL BE IN THE UPPER 20S TO AROUND 30
WITH LOWS SATURDAY NIGHT DROPPING BACK INTO THE MID-UPPER TEENS.
SUNDAY THROUGH WEDNESDAY...
SHORT-TERM UPPER LEVEL RIDGING WILL BUILD INTO THE REGION ON SUNDAY
IN THE WAKE OF THE FRIDAY/SATURDAY SYSTEM. WITH HIGH PRESSURE
DEPARTING TO THE EAST, WE SHOULD GET INTO A RETURN FLOW PATTERN
WHICH WILL ALLOW TEMPS TO RECOVER A BIT. HIGHS ON SUNDAY LOOK TO
WARM INTO THE LOW-MID 30S, WITH OVERNIGHT LOWS IN THE LOW-MID 20S.
BY MONDAY, ANOTHER UPPER LEVEL TROUGH AXIS IS FORECAST TO SWING
THROUGH THE GREAT LAKES BRINGING ANOTHER SURGE OF COLDER AIR INTO
THE REGION. THE GLOBAL MODELS CONTINUE TO BACK OFF ON MOISTURE
RETURN AHEAD OF THE SYSTEM. THIS IS LIKELY WAY OVERDONE AND WE'RE
LIKELY TO SEE SOME ADDITIONAL SNOW SHOWERS/FLURRIES WITH THIS SYSTEM
AS IT PASSES THROUGH. COULD THIS BRING SOME ADDITIONAL SNOW
ACCUMULATIONS? YES, IT COULD WITH THE HIGHEST RISKS ACROSS INDIANA,
OHIO, AND PORTIONS OF NORTHERN AND NORTHEAST KY. AFTER THIS WAVE
PASSES, DRY AND COLD CONDITIONS ARE EXPECTED FOR TUESDAY AND
WEDNESDAY.
================================================
EXTENDED FORECAST DISCUSSION (BEYOND WEDNESDAY)
================================================
BEYOND WEDNESDAY, THERE IS AN INCREASING SIGNAL WITHIN THE GLOBAL
DATA THAT WE'LL SEE THE COLD WEATHER RELENT SLIGHTLY AS THE UPPER
PATTERN TAKES A 180. TOWARD THE 17TH, IT IS POSSIBLE THAT RIDGING
ACROSS THE WEST WILL PUSH EASTWARD AS HIGH LATITUDE BLOCKING BREAKS
DOWN. THIS SHOULD ALLOW THE EASTERN US TROUGH TO TRANSLATE EASTWARD
AND ALLOW HEIGHTS TO RISE ALONG WITH TEMPERATURES. HOWEVER, THIS
LOOKS TO BE SHORT-LIVED AS THE PATTERN LOOKS TO RELOAD AND
SIGNIFICANT RIDGING RETURNS TO THE EASTERN PACIFIC LEADING TO A MUCH
COLDER PATTERN RETURNING TO THE CENTRAL AND EASTERN US BY THE 19TH
OR 20TH.
LONG RANGE SIGNAL ANALYSIS FROM EARLY JANUARY HAS BEEN RATHER
BULLISH WITH A SIGNAL CROSSING IN THE 1/19-1/21 TIME FRAME WITH
ANOTHER STRONG SIGNAL IN THE 1/24 TO 1/26 TIME FRAME. WE'LL LIKELY
SEE SOME UPS/DOWN IN THE TEMPS AHEAD AND BEHIND THESE SIGNAL
CROSSINGS. HOWEVER, THERE IS AN INCREASINGLY STRONG SIGNAL THAT
WIDESPREAD COLD WILL RETURN TO MUCH OF THE CENTRAL AND EASTERN US TO
CLOSE OUT THE MONTH OF JANUARY. ON A WHOLE, THE MONTH WILL LIKELY
AVERAGE WELL BELOW NORMAL IN TERMS OF TEMPERATURES.
AVIATION /18Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 1216 PM EST THU JAN 9 2025
CONFIDENCE/IMPACTS:
- LOW TO MEDIUM CONFIDENCE IN PERIODS OF MVFR CONDITIONS FRIDAY
MORNING.
DISCUSSION...SURFACE HIGH PRESSURE OVER THE REGION WILL SLOWLY MOVE
EASTWARD TODAY AND TONIGHT BOLSTERING CONFIDENCE IN VFR CONDITIONS
THROUGH MOST OF TAF PERIOD. FOR TODAY, WINDS WILL REMAIN LIGHT AND
VARIABLE WITH CLEAR SKIES. THEN, SURFACE LOW PRESSURE TRACKING ALONG
THE GULF COAST AND COLD FRONT APPROACHING FROM THE MIDWEST WILL
ALLOW CLOUDY CONDITIONS AND WEAK SOUTHERLY WINDS TONIGHT INTO
TOMORROW WITH LIGHT SNOW CHANCES STARTING AFTER SUNRISE ON FRIDAY.
ALTHOUGH SNOW ACTIVITY DURING FRIDAY MORNING SHOULD BE LIGHT, THERE
COULD BE PERIODS OF MVFR CONDITIONS CLOSER TO 18Z.
LMK WATCHES/WARNINGS/ADVISORIES
KY...WINTER STORM WARNING FROM 4 AM EST /3 AM CST/ FRIDAY TO 7 AM
EST /6 AM CST/ SATURDAY FOR KYZ023>043-045>049-053>057-
061>067-070>078-081-082.
IN...WINTER STORM WARNING FROM 4 AM EST /3 AM CST/ FRIDAY TO 7 AM
EST /6 AM CST/ SATURDAY FOR INZ076>079-083-084-089>092.
UPDATE...ALL
SHORT TERM...BTN
LONG TERM...MJ
AVIATION...ALL
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