623
FXUS63 KJKL 042100
AFDJKL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
400 PM EST SUN DEC 4 2022
SHORT TERM
(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 400 PM EST SUN DEC 4 2022
20Z SFC ANALYSIS SHOWS HIGH PRESSURE OVER KENTUCKY TODAY AND THIS
HAS KEPT THE WINDS LIGHT, RELATIVE HUMIDITIES LOW, AND PUSHED THE
HIGH CLOUDS FURTHER SOUTH THROUGH THE STATE. TEMPERATURES ENDED
UP ON THE COOL SIDE OF NORMAL WITH READINGS CURRENTLY IN THE LOW
TO MID 40S WHILE DEWPOINTS ARE RUNNING IN THE MID TO UPPER 20S
MOST PLACES.
THE MODELS REMAIN IN EXCELLENT AGREEMENT ALOFT THROUGH THE SHORT
TERM PORTION OF THE FORECAST. THEY ALL DEPICT THE MID LEVEL
PATTERN SHIFTING FROM NORTHWESTERLY TONIGHT TO MORE SOUTHWESTERLY
BY TUESDAY MORNING. THIS WILL INCREASINGLY BRING IN DEEP LAYER
MOISTURE TO START THE WORK WEEK WITH JUST SOME WEAK PACKETS OF
ENERGY FLOWING THROUGH IN THAT STREAM. GIVEN THE VERY SMALL MODEL
SPREAD DURING THIS TIME HAVE AGAIN FAVORED THE BLENDED NBM
SOLUTION FOR THE STARTING POINT OF THE FORECAST GRIDS WITHOUT MUCH
ADJUSTMENT NEEDED.
SENSIBLE WEATHER WILL FEATURE A COOL EVENING AND START TO THE
NIGHT AS GOOD RADIATIONAL COOLING CONDITIONS LIKELY LEAD TO A
DECENT RIDGE TO VALLEY TEMPERATURE SPLIT BEFORE THE CLOUDS START
TO THICKEN UP AND STEADY THE TEMPERATURES A FEW HOURS AFTER
MIDNIGHT. LOOK FOR SOME RISE TOWARDS DAWN MOST SPOTS WITH THICK
CLOUDS AND THE APPROACH OF THE FIRST WAVE OF PCPN BRINGING IN
WARMER CONDITIONS AND MOISTURE. THE MOISTURE WILL EVENTUALLY
SATURATE DOWN ENOUGH, AND OVERCOME SOME DOWNSLOPING, TO RESULT IN
SHOWERS REACHING THE SFC BY MID TO LATE AFTERNOON MOST PLACES.
THIS INITIAL ROUND OF SHOWERS AND OVERRUNNING WILL THEN PROVIDE A
GOOD SOAKING RAIN MONDAY NIGHT INTO TUESDAY MORNING WITH
CATEGORICAL POPS IN ORDER. UP TO THREE QUARTERS OF AN INCH OF
RAINFALL IS EXPECTED FROM THIS MAINLY FAVORING THE CUMBERLAND
VALLEY AND HEADWATERS - LIKELY SETTING THE STAGE FOR MORE
SATURATED ANTECEDENT CONDITIONS FOR THE NEXT ROUNDS OF RAIN.
TEMPERATURES WILL BE WARMER FOR HIGHS MONDAY THAN TODAY WITH MUCH
MILDER READINGS MONDAY NIGHT - NEARLY STEADY IN THE 40S DURING
THE RAIN.
DID MAKE SOME ADJUSTMENT TO HOURLY TEMPERATURES TONIGHT TO BETTER
CAPTURE THE TERRAIN DISTINCTIONS FOR AT LEAST THE FIRST PART OF
THE NIGHT. AS FOR POPS, MAINLY JUST INCLUDED SOME OF THE CAMS
SPECIFICS THROUGH TUESDAY MORNING - BETTER HONING IN ON THE
TIMING OF THE HIGHEST RAIN CHANGES.
LONG TERM
(TUESDAY THROUGH SUNDAY)
ISSUED AT 240 PM EST SUN DEC 4 2022
KEY POINTS:
* SEVERAL DISTURBANCES EXPECTED TO RIDE A QUASI-STATIONARY SURFACE
BOUNDARY, WHICH WILL BRING SEVERAL RAINFALL OPPORTUNITIES TUESDAY
THROUGH FRIDAY.
* STORM TOTAL RAINFALL AMOUNTS OF 2 TO 3 INCHES EXPECTED THROUGH
THIS TIME.
* TEMPERATURES AVERAGE ABOVE NORMAL THROUGH THE WORK WEEK, DIPPING
BACK TO NEAR SEASONAL READINGS THIS WEEKEND.
THE EXTENDED FORECAST CONTINUES TO COME INTO BETTER AGREEMENT, WHERE
AN UNSETTLED, GLOOMY, AND SOGGY WEATHER PATTERN CAN BE EXPECTED
THROUGH MUCH OF THIS UPCOMING WEEK. STARTING FIRST ALOFT, EASTERN
KENTUCKY WILL BE WEDGED BETWEEN AN EXPANSIVE 588 DAM RIDGE DOME
ACROSS THE CENTRAL GULF OF MEXICO, WHILE A BROAD LONGWAVE TROUGH AND
A SERIES OF RIDING SHORTWAVES SIT NORTH ACROSS THE HUDSON BAY AND
THROUGH SOUTHERN CANADA. THIS WILL RESULT IN A SW TO NE ORIENTED
FLAT FLOW, WHICH WILL BE IN PLACE THROUGH AT LEAST THURSDAY. FURTHER
WEST, A 548 DAM LOW IS ATOP THE MODOC PLATEAU AND WILL MEANDER EAST
THROUGH MID WEEK, BRINGING REINFORCING SHOWER CHANCES TO THE REGION
THURSDAY AND INTO FRIDAY. AT THE SURFACE, THE COLD FRONT THAT
BROUGHT COOLER TEMPERATURES TO THE AREA (TODAY) WILL RE-ESTABLISH
ITSELF, BENDING BACK NORTH IN THE FORM OF A WARM FRONT TUESDAY
MORNING. THETA-E ANALYSIS SUGGESTS THIS BOUNDARY TO STALL JUST TO
OUR NORTH ACROSS THE OHIO VALLEY, ALLOWING FOR A FOCUS FOR DEEP
MOISTURE TO ADVECT IN OFF THE GULF. DETERMINISTIC MODELS SUGGEST
PWATS BETWEEN 1 AND 1.5" THROUGH LATE WORK WEEK, WHICH IS BETWEEN
THE 75TH PERCENTILE AND 2 STANDARD DEVIATIONS ABOVE THE NORM. IN
COMPARISON, THE ENS AND GEFS, ALIKE, HIGHLIGHT THE ANOMALOUS
MOISTURE, WITH MEMBER MEANS SUGGESTING PWATS OVER 200% OF THE NORM
FOR EARLY DECEMBER. WITH THAT SAID, THE RIDING AREAS OF LOW
PRESSURE ALONG THE BOUNDARY SHOULD BE PROGRESSIVE ENOUGH TO LIMIT
MOST HYDRO CONCERNS. RAINFALL RATES SHOULD GENERALLY BE LIGHT TO
MODERATE AND WITH THE AID OF DRY ANTECEDENT CONDITIONS, SOILS
SHOULD BE ABLE TO HANDLE THE RAINFALL. THAT SAID, AND MENTIONED IN
THE PREVIOUS DISCUSSION, BASINS WILL LIKELY SEE AN INCREASE IN
LEVELS GIVEN THE SATURATED GROUNDS AND ROUNDS OF RAINFALL. THE QPF
REMAINS LARGELY IN CHECK, WHERE 2 TO 3 INCHES ARE EXPECTED
THROUGH FRIDAY.
BREAKING THIS DOWN FURTHER, THE WARM FRONT WILL BUILD NORTH TUESDAY,
ALLOWING FOR SHOWERS TO OVERSPREAD THE AREA FROM S TO N INTO THE
EARLY MORNING. WITH THE BOUNDARY SITTING NEARBY, AREAS OF LOW
PRESSURE WILL DEVELOP ALONG IT, BRINGING ROUNDS OF SHOWERS AND THE
CHANCE FOR A FEW THUNDERSTORMS (TUESDAY THROUGH WEDNESDAY). THE
UPPER LEVEL PATTERN THEN BEGINS TO EVOLVE BEYOND WEDNESDAY, AS THE
AFOREMENTIONED CALIFORNIA CLOSED LOW WILL NOW BE TREKKING THROUGH
THE CENTRAL PLAINS, EJECTING ACROSS THE OHIO VALLEY, AND
EVENTUALLY MEANDERING OFF THE COAST OF THE CHESAPEAKE BAY AREA
THIS WEEKEND. HEIGHTS WILL LOWER THROUGH THURSDAY, WHERE A COLD
FRONT WILL INDUCE WIDESPREAD SHOWERS AHEAD AND ALONG IT AFTER 12Z.
FROPA WILL BE INTO MIDDAY FRIDAY, BUT UPSLOPE FLOW WILL LEND TO
LINGERING SHOWER CHANCES, PARTICULARLY ACROSS THE SE INTO EARLY
SATURDAY MORNING. RISING HEIGHTS ASSOCIATED WITH SHORTWAVE RIDGING
WILL THEN SLIDE IN SATURDAY, BRINGING TEMPORARILY DRIER AND
COOLER CONDITIONS THROUGH MUCH OF THE DAY. HAVE HELD OFF ON THE
REINTRODUCTION OF POPS ASSOCIATED WITH ANOTHER WAVE LATE IN THE
PERIOD, AS THE NBM SEEMED A BIT PROGRESSIVE COMPARED TO
DETERMINISTIC AND SOME OF THE ENSEMBLES. NONETHELESS, AN
OPPORTUNITY FOR CHANCE SHOWERS (30-40%) DOES RETURN INTO SUNDAY
MORNING.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1250 PM EST SUN DEC 4 2022
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. LOOK FOR MID AND
HIGH CLOUDS TO THIN AND SHIFT SOUTH THROUGH THE AFTERNOON. CLOUDS
WILL THEN INCREASE ONCE AGAIN LATE TONIGHT OUT AHEAD OF THE NEXT
SYSTEM APPROACHING FROM THE SOUTHWEST. ANY PCPN THREAT FROM THIS
WAVE WILL LIKELY HOLD OFF UNTIL AFTER THIS AVIATION PERIOD. EXPECT
WINDS TO AVERAGE AROUND 5 KTS OR LESS THROUGH MONDAY AFTERNOON.
JKL WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...GREIF
LONG TERM...BB
AVIATION...GEOGERIAN/GREIF
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