336
FXUS63 KLMK 190820
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
320 AM EST WED FEB 19 2025
KEY MESSAGES
* ONGOING WINTER STORM WILL NEGATIVELY IMPACT THE WEDNESDAY MORNING
COMMUTE WITH DANGEROUS ROAD CONDITIONS AND REDUCED VISIBILITIES.
MODERATE TO HEAVY SNOW WILL END FROM WEST TO EAST THIS MORNING,
AND DRIER WEATHER IS EXPECTED FOR THE LATE MORNING AND AFTERNOON
HOURS.
* ANOTHER ROUND OF SNOW TONIGHT COULD PRODUCE A HALF INCH UP
TO AN INCH ACROSS THE AREA BY THURSDAY MORNING.
* VERY COLD TEMPERATURES ARE EXPECTED AFTER THE WINTER STORM. WIND
CHILLS BELOW ZERO WILL BE POSSIBLE THURSDAY MORNING. WITH SINGLE
DIGIT LOWS FOR FRIDAY MORNING.
* MOSTLY DRY WEATHER THURSDAY THROUGH TUESDAY, WITH NO HEAVY RAIN
OR SNOW EXPECTED. TEMPERATURES WILL RISE ABOVE FREEZING SATURDAY.
MESOSCALE
ISSUED AT 158 AM EST WED FEB 19 2025
MOST SNOW REPORTS SO FAR HAVE BEEN IN THE 2-3 INCH RANGE ACROSS
CENTRAL KENTUCKY. HERE AT THE WFO, WE HAVE MEASURED HALF AN INCH OF
SNOW SO FAR IN SOUTHERN LOUISVILLE. REGIONAL RADAR RETURNS CONTINUE
TO HIGHLIGHT CENTRAL KENTUCKY WITH THE HEAVIER SNOW BANDS, WHICH IS
THE AREA OF FOCUS DUE TO LIFT FROM 700 MB WARM TEMPERATURE ADVECTION
AND LOW LEVEL CONVERGENCE UNDERNEATH THE ENTRANCE REGION OF THE
UPPER JET STREAK. POLEWARD FRONTOGENETICAL FORCING COMBINED WITH A
GRADIENT OF SLIGHTLY DEEPER DENDRITIC GROWTH LAYER DEPTHS AND
DENDRITIC LAYER RH IS SUPPORTING HIGHER SNOWFALL RATES ACROSS THE
CENTRAL PART OF THE STATE. HOWEVER, THE MESOANALYSIS SHOWS MUCH
DEEPER GROWTH LAYERS ACROSS SOUTHEAST MISSOURI AND FAR WESTERN
KENTUCKY, WHICH IS WHERE HEAVIER SNOWFALL TOTALS HAVE BEEN COMING
IN. SNOWFALL IS EXPECTED TO CONTINUE THROUGH THE MORNING, WITH
ADDITIONAL SNOWFALL AMOUNTS UP TO 2-3 INCHES POSSIBLE FOR KENTUCKY
COUNTIES MAINLY ALONG AND SOUTH OF I-64.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 319 AM EST WED FEB 19 2025
NEGATIVE IMPACTS TO THE WEDNESDAY MORNING COMMUTE ARE EXPECTED AS
MODERATE TO HEAVY SNOW SHIFTS ACROSS THE REGION THIS MORNING. WITH A
DRY SNOW IN PLACE, AND WINDS UP TO 10-15 MPH, WE COULD SEE SOME
BLOWING SNOW, WHICH COULD REDUCE VISIBILITIES AT TIMES.
HEAVIER SNOWFALL WILL BE GRADUALLY TAPERING OFF THIS MORNING AS THE
PRIMARY MOISTURE LAYER DEPARTS TO THE EAST WITH THE UPPER LEVEL JET
CORE. WE'LL HAVE SOME LIGHT SNOW OR FLURRIES THROUGH THE MID-
MORNING, BUT THERE CONTINUES TO BE GOOD MODEL CONSENSUS THAT WE GET
A LARGE DRY SLOT WORKING INTO THE REGION THIS AFTERNOON. DRY
CONDITIONS ARE MOST LIKELY AREA-WIDE BETWEEN APPROXIMATELY 15-22Z
TODAY. GIVEN THAT WE WILL HAVE BRISK NORTHERLY SFC WINDS AND
SNOWPACK, DID DROP TODAY'S MAX TEMPS SLIGHTLY FROM THE NBM, WITH
HIGHS IN THE LOW TO MID 20S ACROSS THE FORECAST AREA.
THE LARGE UPPER LOW WILL BE SLOWLY SPINNING FROM MINNESOTA THIS
MORNING TOWARD LAKE MICHIGAN THIS EVENING, WHICH WILL HELP KEEP THE
MAIN UPPER TROUGH AXIS OVERHEAD. AS THIS UPPER LOW PIVOTS, ANOTHER
SHORTWAVE WILL PINWHEEL AROUND THE PRIMARY TROUGH AXIS, AND WE'LL
GET ANOTHER MID-LEVEL VORT MAX TO SWING THROUGH THE LOWER OHIO
VALLEY THIS EVENING. WHILE WE WILL SEE AN INCREASE IN MOISTURE IN
THE 850-500 MB LAYER, THE COLUMN WILL NOT BE NEARLY AS SATURATED AS
WITH THE MORNING WAVE. SOUNDINGS CONTINUE TO SHOW STEEP LOW LEVEL
LAPSE RATES, WITH ENOUGH SATURATION THROUGH THE DGZ TO OUTPUT SOME
SNOW SHOWERS THIS EVENING. OVERALL RH VALUES AND WINDS WILL NOT BE
SUBSTANTIAL ENOUGH FOR SNOW SQUALL CONCERNS, BUT GIVEN THE COLD
TEMPS WE EXPECT TO SEE PRETTY HIGH SNOW RATIOS. DESPITE THE LIMITED
QPF, 20:1 RATIOS ARE SUPPORTIVE FOR AN ADDITIONAL 0.5-1 INCH OF DRY
SNOW, MAINLY ACROSS SOUTHERN INDIANA AND NORTH-CENTRAL KENTUCKY.
MOST LIKELY TIME FRAME FOR ACCUMULATING SNOWFALL WILL BE BETWEEN 00-
06Z TONIGHT. WHILE ADVISORY LEVEL SNOW AMOUNTS WILL BE MORE
ISOLATED, WILL CONTINUE THE WINTER WEATHER ADVISORY FOR TONIGHT FOR
AWARENESS OF ADDITIONAL SNOWS AFTER THE WINTER STORM DEPARTS.
THE UPPER TROUGH AXIS WILL BEGIN TO SHIFT EAST OF THE REGION BEFORE
SUNRISE THURSDAY. WHEN DOING SO, CANADIAN SFC HIGH PRESSURE WILL BE
SETTLING IN ACROSS THE GREAT PLAINS, WHICH WILL REINFORCE OUR
NORTHERLY SFC FLOW AND CAA REGIME. WITH THE SNOWPACK ALREADY IN
PLACE, WE WILL SEE OUR TEMPS CRASH TONIGHT, WITH HIGH CONFIDENCE IN
SINGLE DIGIT TEMPS WEST OF I-65. LOWER TEENS ARE EXPECTED TO THE
EAST. WITH SFC WINDS REMAINING SOMEWHAT TURBULENT OVERNIGHT, THIS
WILL RESULT IN WIND CHILL VALUES DROPPING TO NEAR ZERO ACROSS THE
ENTIRE FORECAST AREA, AND LIKELY INTO NEGATIVE VALUES IN OUR WEST.
THESE VERY COLD TEMPS ARE ESPECIALLY CONCERNING GIVEN THE ONGOING
RECOVERY EFFORTS FROM THE FLOODS. THE COLD WEATHER ADVISORY REMAINS
FOR THURSDAY MORNING.
LONG TERM /THURSDAY THROUGH TUESDAY/
ISSUED AT 319 AM EST WED FEB 19 2025
THERE WILL BE ENOUGH LOW LEVEL MOISTURE THURSDAY MORNING TO SUPPORT
A FEW LINGERING SNOW SHOWERS, ESPECIALLY FROM SOUTHEAST INDIANA INTO
THE BLUEGRASS WHERE THERE WILL BE SOME CONTRIBUTION FROM LAKE
MICHIGAN. ANY SHOWERS SHOULD BE ISOLATED AND LIGHT. COLD ADVECTION
ON THE EAST SIDE OF A STRONG RIDGE OF HIGH PRESSURE OVER THE PLAINS
WILL PROVIDE US WITH ANOTHER COLD DAY, WITH AFTERNOON HIGHS AROUND
20.
THAT HIGH WILL SLOWLY PUSH ESEWD THROUGH THE WEEKEND. THOUGH SEVERAL
RIPPLES IN THE UPPER FLOW WILL PASS OVERHEAD SATURDAY, SATURDAY
NIGHT, AND SUNDAY, THE STRONG SURFACE HIGH AND LOW ATMOSPHERIC
MOISTURE WILL KEEP US DRY. AS THE HIGH PUSHES EAST AND WEAKENS,
WE'LL SEE A MODERATION IN TEMPERATURES. ON SATURDAY ALL LOCATIONS
WILL CLIMB ABOVE FREEZING, AND ON SUNDAY WE'RE EXPECTING HIGHS IN
THE 40S...JUST A FEW DEGREES COOLER THAN NORMAL.
MONDAY A CLIPPER WILL DIVE SOUTHEAST AND PASS OVER THE GREAT LAKES,
KEEPING ITS ASSOCIATED PRECIPITATION NORTH OF US. ON TUESDAY ANOTHER
CLIPPER WILL APPROACH ON A SLIGHTLY MORE SOUTHWARD TRACK, AND COULD
BRING A FEW ISOLATED SHOWERS TO THE OHIO VALLEY. BY TUESDAY SOUTHERN
KENTUCKY WILL BE FLIRTING WITH 60 DEGREES!
AVIATION /06Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 1222 AM EST WED FEB 19 2025
THE WINTER STORM IS UNDERWAY ACROSS THE REGION, IMPACTING THE
TERMINALS THIS MORNING WITH -SN AND REDUCED VIS DOWN TO 3/4SM.
EXPECT THESE SNOW BANDS AND IMPACTS TO CONTINUE THROUGH THE PREDAWN
HOURS. AFTER SUNRISE, SOME SNOW MAY LINGER BUT IMPROVEMENTS TO VIS
ARE FORECAST. DRIER CONDITIONS WILL SET IN FOR THE LATE MORNING AND
AFTERNOON TIME FRAME, THOUGH THE CLOUD DECK IS EXPECTED TO REMAIN IN
MVFR TODAY. A SECOND WAVE OF -SN IS LIKELY THIS EVENING, WHICH COULD
ONCE AGAIN BRING IMPACTS FOR THE LATE NIGHT HOURS.
LMK WATCHES/WARNINGS/ADVISORIES
KY...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR KYZ031>033-
037-043.
WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS
AFTERNOON TO 7 AM EST /6 AM CST/ THURSDAY FOR KYZ023>043-
045>049-053>057-063>067-077-078.
COLD WEATHER ADVISORY FROM 1 AM EST /MIDNIGHT CST/ TO 11 AM
EST /10 AM CST/ THURSDAY FOR KYZ023>043-045>049-053>057-
061>067-070>078-081-082.
WINTER STORM WARNING UNTIL NOON EST /11 AM CST/ TODAY FOR
KYZ023>030-034>036-038>042-045>049-053>057-061>067-
070>078-081-082.
IN...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR INZ076>079-
083-084-091-092.
WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS
AFTERNOON TO 7 AM EST /6 AM CST/ THURSDAY FOR INZ076>079-
083-084-089>092.
COLD WEATHER ADVISORY FROM 1 AM EST /MIDNIGHT CST/ TO 11 AM
EST /10 AM CST/ THURSDAY FOR INZ076>079-083-084-089>092.
WINTER STORM WARNING UNTIL NOON EST /11 AM CST/ TODAY FOR
INZ089-090.
MESOSCALE...CJP
SHORT TERM...CJP
LONG TERM...13
AVIATION...CJP
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