166
FXUS63 KJKL 131758 AAC
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
1258 PM EST MON JAN 13 2025
KEY MESSAGES
- PATCHY FREEZING DRIZZLE OR LIGHT SNOW SHOWERS ARE POSSIBLE INTO
EARLY AFTERNOON, GENERALLY EAST OF I-75.
- THERE IS THE POTENTIAL FOR SOME LIGHT ACCUMULATING SNOW TUESDAY
AFTERNOON INTO EVENING.
- APPARENT TEMPERATURES COULD FALL TO NEAR OR BELOW ZERO FOR A FEW
LOCATIONS TONIGHT AND IN MANY PLACES ON TUESDAY AND WEDNESDAY
NIGHTS - PRIMARILY NORTH OF THE MOUNTAIN PARKWAY.
UPDATE
ISSUED AT 1109 AM EST MON JAN 13 2025
SO FAR, THERE HAVE BEEN NO REPORTS OF LIGHT PRECIPITATION AS A
COLD FRONT IS CROSSING THE AREA. RADAR HAS ALSO BEEN DEVOID OF
RETURNS. SOME LIGHT PRECIPITATION CANNOT BE COMPLETELY RULED OUT
INTO THE AFTERNOON. HOURLY GRIDS WERE FRESHENED UP BASED ON RECENT
OBSERVATIONS AND TRENDS.
UPDATE ISSUED AT 640 AM EST MON JAN 13 2025
SO FAR WE HAVE NOT SEEN ANY REPORTS OF PCPN REACHING THE GROUND
WHICH IS GOOD NEWS GIVEN TEMPERATURES NEAR THE FREEZING THRESHOLD
WITH LITTLE PROSPECT OF ICE CRYSTALS OUTSIDE OF THE CIRRUS AREAS
IN THE FAR SOUTHEAST. WILL CONTINUE THE FORECAST AS IS THROUGH THE
MORNING DUE TO THE POTENTIAL FOR SOME LIGHT PCPN TO REACH THE
GROUND WITH THE ACCOMPANYING COLD FRONT. OTHERWISE, HAVE MAINLY
ADJUSTED THE FORECAST TO ADD IN THE LATEST OBS AND TRENDS FOR THE
T/TD/SKY GRIDS. THESE MINOR ADJUSTMENTS HAVE BEEN SENT TO THE NDFD
AND WEB SERVERS ALONG WITH A FRESHENING OF THE ZONES AND SAFS.
SHORT TERM
(TODAY THROUGH TUESDAY)
ISSUED AT 440 AM EST MON JAN 13 2025
09Z SFC ANALYSIS SHOWS A MOISTURE STARVED COLD FRONT CROSSING INTO
EASTERN KENTUCKY FROM THE NORTHWEST. THIS IS BRINGING WITH IT A
REINFORCING SURGE OF COLD AIR ALONG WITH ENOUGH LIFT TO SUPPORT
SOME LIGHT PCPN EVEN IF IT IS NOT SHOWING UP IN ANY OBS OR EVEN ON
RADAR. IN THE SOUTH, HIGH CLOUDS ARE OVERRUNNING THE LOWER CLOUDS
AND THIS COULD ADD SOME ICE CRYSTALS INTO THE SHALLOW MOISTURE
LAYER BELOW. THE EARLIER CLEARING FOR MUCH OF EASTERN KENTUCKY HAD
ALLOWED FOR GOOD RADIATIONAL COOLING YIELDING TEMPERATURES FALLING
INTO THE UPPER TEENS AND LOWER 20S FOR SHELTERED VALLEYS. NOW
THOUGH, THANKS TO THOSE CLOUDS MOVING IN, READINGS ARE NOT SO
STRIATED WITH MID 20S FOUND IN THOSE VALLEYS RANGING TO THE MID
30S IN THE NORTHWEST PORTION OF THE JKL CWA - AHEAD OF THAT
FRONT. AMID LIGHT WINDS WITH A SOUTHERN TENDENCY, DEWPOINTS ARE
RUNNING IN THE MID TO UPPER 20S MOST PLACES.
THE MODELS, AND THEIR INDIVIDUAL ENSEMBLE SUITES, ARE STILL IN
DECENT AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE
FORECAST. THEY ALL DEPICT INCREASINGLY ZONAL FLOW AT MID LEVELS AS
A DYNAMIC PATTERN ADJUSTMENT TAKES PLACE OVER NORTH AMERICA. THE
MAIN TROUGH CURRENTLY OVER THE ROCKIES AND PLAINS - BUT CENTERED
NORTH OF MINNESOTA - WILL TIGHTEN UP DRAMATICALLY OVER THE STATES
AS THE TROUGH CORE ROTATES INTO THE UPPER MIDWEST AND THROUGH THE
GREAT LAKES BY TUESDAY MORNING. HOWEVER, STRONG RIDGING TO THE
SOUTH OF KENTUCKY - CENTERED OVER CUBA - WILL HOLD FAST ZONAL MID
LEVEL FLOW OVER KENTUCKY. IN THIS FLOW A STREAM OF ENERGY SETTLES
INTO THE AREA ALONG WITH SOME SLIGHT HEIGHT FALLS TODAY INTO
TUESDAY. MEANWHILE, THE HEART OF THE ORIGINAL TROUGH SWINGS PAST
THE AREA BY TUESDAY EVENING PUSHING ITS 5H AXIS THROUGH EASTERN
KENTUCKY. RIDGING THROUGH THE GULF WILL LEAVE THESE IMPULSES WITH
ONLY SHALLOW MOISTURE TO WORK WITH - LIMITING GROUND LEVEL IMPACTS
DESPITE SUCH DYNAMICS ALOFT. THE RELATIVELY SMALL MODEL SPREAD
ALOFT MADE THE NBM A SOLID STARTING POINT FOR THE FORECAST GRIDS,
THOUGH WITH SOME ADJUSTMENT PER THE LATEST CAMS FOR POPS TODAY
AND TUESDAY, BUT MOSTLY HAND DRAWN FROM EXPERIENCE AND
CLIMATOLOGY.
SENSIBLE WEATHER FEATURES A PERIOD OF ABOVE FREEZING TEMPERATURES
TODAY FOR MOST WHICH WILL MITIGATE THE CONCERNS OF ANY LIGHT
FROZEN OR FREEZING PCPN AS WELL AS SERVE TO HELP THAW THE AREA
OUT JUST A BIT MORE. THE INITIAL CONCERN WILL BE THAT COLD FRONT
SETTLING INTO THE AREA THIS MORNING AND EARLY IN THE AFTERNOON
FROM NORTHWEST TO SOUTHEAST. THE DYNAMICS ALOFT AND SOME MOISTURE
STILL TRAPPED IN THE LOW LEVELS SHOULD BE ENOUGH FOR SPOTTY LIGHT
PCPN MAINLY IN THE FORM OF DRIZZLE BUT WITH SOME PATCHES OF
FREEZING DRIZZLE POSSIBLE IN THE COLDER POCKETS OF EASTERN
KENTUCKY. THERE WILL BE A TENDENCY FOR THE LIGHT PCPN TO GO OVER
TO FLURRIES WITH TIME AS THE COLDER AIR ALOFT - BEHIND THE FRONT -
HELPS TO GENERATE SOME ICE CRYSTALS IN THE TOP OF THE CLOUD. IN
ADDITION, A SEEDER FEEDER MECHANISM OF THE HIGH CLOUDS DROPPING
ICE CRYSTALS INTO THE SUB FREEZING CLOUDS BELOW WOULD LIKELY
INITIATE A CHANGE TO LIGHT SNOW. THE CUMBERLAND VALLEY LOOKS TO
HAVE THE BEST SHOT OF THIS OCCURRING THIS MORNING. THE FRONT AND
ITS LIGHT PCPN POTENTIAL MOVES OUT BY LATE AFTERNOON AND A MOSTLY
CLEAR NIGHT WILL SET UP RADIATIONAL COOLING CONDITIONS ALONG WITH
A MODERATE RIDGE TO VALLEY TEMPERATURE SPLIT. TEMPERATURES WILL
FALL INTO THE TEENS IN THOSE SHELTERED VALLEYS TONIGHT, BUT EVEN
WITH ANY WIND AROUND APPARENT TEMPERATURES (WIND CHILLS) WILL ONLY
BOTTOM OUT NEAR ZERO IN THE NORTH - NOT COLD ENOUGH FOR A COLD
WEATHER ADVISORY, AT THIS TIME. ATTENTION THEN TURNS TO A STRONGER
REINFORCING COLD FRONT INBOUND FOR THE AREA ON TUESDAY WITH
SLIGHTLY DEEPER MOISTURE AVAILABLE AND REACHING INTO THE PRIME
ZONE FOR DENDRITE GROWTH. A SIMILAR SITUATION WAS SEEN LAST WEEK
WHERE MINUSCULE MOISTURE WAS ABLE TO YIELD HOURS OF FLUFFY SNOW
WORTHY OF AN ADVISORY - UNDER THE MODELS NOSE WITHOUT MUCH HINT AT
SUCH A PRODUCTIVE OUTCOME FOR THE SNOW. SO THIS SITUATION BEARS
WATCHING AND WE HAVE GONE HIGHER THAN ANY MODEL TO PRODUCE THE
POTENTIAL FOR SOME LIGHT SNOW ACCUMULATION IN THE FORECAST GRIDS.
WE WILL KEEP MONITORING THIS SITUATION FOR A POSSIBLE SPS OR EVEN
ADVISORY IF THINGS COME TOGETHER AGAIN - CERTAINLY THE UPPER LEVEL
DYNAMICS WILL BE THERE.
THE CHANGES TO THE NBM STARTING POINT CONSISTED PRIMARILY OF
ADDING IN MORE TERRAIN DISTINCTIONS TONIGHT FOR TEMPERATURES AND
TWEAKING THE POPS PER THE LATEST CAMS GUIDANCE. THE POPS WERE
ALSO HAND ADJUSTED UPWARD ON ACCOUNT OF THE MOISTURE DEPTH ON
TUESDAY, WITH THE COLD AIR IN PLACE AND MORE ARRIVING.
THUS OUR WINTER OF DISCONTENT ROLLS ON WITH OMINOUS SIGNS FOR
WORSE DOWN THE ROAD...
LONG TERM
(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 351 AM EST MON JAN 13 2025
THE FORECAST PERIOD BEGINS WITH A CLIPPER SYSTEM DIVING THROUGH THE
OHIO VALLEY. WITH THIS CLIPPER MOVING THROUGH, INCREASED POP IS
EXPECTED BUT AT THE START OF THE PERIOD, THOSE POPS WILL BE
DECREASING AS THE CLIPPER IS FORECAST TO BE EXITING THE PERIOD.
LINGERING SNOW SHOWERS WILL BE EXPECTED THROUGH LATE TUESDAY NIGHT
BEFORE TAPERING OFF. BEHIND THE EXITING CLIPPER, SURFACE HIGH
PRESSURE WILL BUILD INTO THE REGION BUT CAA WILL BRING SOME OF THE
COLDEST TEMPERATURES OF THE SEASON TO EASTERN KENTUCKY. HIGHS
WEDNESDAY ARE FORECAST TO CLIMB INTO THE LOW TO MID-20S WITH
OVERNIGHT LOWS WEDNESDAY AND THURSDAY MORNINGS FALLING INTO THE
NEGATIVES TO SINGLE DIGITS. ANOTHER WEAK TROUGH AND VORT MAX WILL
MOVE THROUGH THE AREA OVERNIGHT THURSDAY. IN THIS MODEL SUITE, THAT
SCENARIO STILL EXISTS; HOWEVER, ITS HAPPENING FURTHER TO THE
NORTHEAST IN WEST VIRGINIA. THEREFORE, KEPT THE POP OUT OF THE CWA
IN THIS TIMEFRAME BUT THAT COULD POSSIBLY CHANGE IN FUTURE FORECASTS
AS THERE'S BEEN PLENTY OF BACK AND FORTH WITH THIS SHORTWAVE.
CONFIDENCE CONTINUES TO LACK IN WHAT'S GOING TO HAPPEN WITH THE
WEEKEND SYSTEM. HOWEVER, MODEL TRENDS CONTINUE TO BRING AN UPPER-
LEVEL TROUGH OUT OF THE FOUR CORNERS FRIDAY MORNING WITH SURFACE
CYCLOGENESIS TAKING PLACE FRIDAY AFTERNOON AS IT APPROACHES THE
COMMONWEALTH. LONG-TERM DETERMINISTIC FORECASTS DISAGREE ON THE
TIMING AND PLACEMENT OF THIS SYSTEM AND HAVE ESSENTIALLY SWITCHED
SOLUTIONS WITH THE GFS BEING A SLOWER SYSTEM AND THE ECMWF BEING THE
QUICKER, MORE AGGRESSIVE SOLUTION. WITH THAT BEING SAID, CONTINUED TO
LEAN TOWARD THE NBM SOLUTION WHICH BRINGS INCREASING POP FROM ;ATE
FRIDAY MORNING AND CONTINUING THROUGH THE WEEKEND. TEMPERATURES WILL
BE WARM ENOUGH TO SUPPORT RAIN WHICH COUPLED WITH SNOWMELT, THERE
COULD BE INSTANCES OF HIGH WATER. FORTUNATELY, COLDER AIR WILL
FILTER IN BEHIND THE EXITING SYSTEM ON LATE SUNDAY NIGHT AND WILL
TURN RAIN INTO SNOW FOR ALL LINGERING BACKSIDE PRECIPITATION. CAA
WILL BRING A RETURN TO MID-20S HIGHS FOR MONDAY.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1258 PM EST MON JAN 13 2025
MOSTLY VFR WAS REPORTED ACROSS THE REGION AT ISSUANCE TIME WITH
MVFR IN SOME SPOTS AS A COLD FRONT CROSSES THE REGION. A MIXTURE
OF MVFR AND VFR IS EXPECTED TO BEGIN THE PERIOD AND SOME LIGHT
PRECIPITATION WITH NO REDUCTIONS IN VISIBILITY CANNOT BE RULED
OUT IN A FEW SPOTS OVER THE FIRST 3 TO 5 HOURS OF THE PERIOD.
WINDS WILL INITIALLY BE FROM THE SOUTHWEST AT 5 TO 10 KT NEARER TO
THE VA BORDER AHEAD OF IT, WITH WEST TO NORTHWEST WINDS BEHIND
IT. WINDS WILL BECOME WESTERLY IN ALL AREAS DURING THE FIRST
COUPLE HOURS OF THE PERIOD AT 5 TO 10KT AND THEN BECOME VARIABLE
AT 5KT OR LESS DURING THE 00Z AND 12Z TIMEFRAME.
JKL WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...VORST
AVIATION...JP
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