759
FXUS64 KMRX 171149
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
649 AM EST TUE DEC 17 2024
..NEW AVIATION
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 318 AM EST TUE DEC 17 2024
KEY MESSAGES:
1. CLOUDS, SCATTERED SHOWERS, AND PERIODIC PATCHY FOG THROUGH
TONIGHT. MILD TEMPERATURES TO CONTINUE.
DISCUSSION:
RAIN SHOWER COVERAGE AND ACTIVITY SHOULD CONTINUE A GRADUAL
DECREASING TREND TODAY AS UPPER JET FORCING CONTINUES TO SEPARATE
FROM THE OVERNIGHT CONVECTION. STILL, THERE'S A LOW CHANCE FOR
SHOWERS TODAY, AS SHOWN BY ENSEMBLE CAM GUIDANCE, ESPECIALLY IN
THE SOUTHERN HALF OF THE AREA, EVEN AFTER THE EARLY MORNING RAINS
MOVE OUT.
THE "COLD FRONT" IF WE CAN EVEN CALL IT COLD, IS EXPECTED TO STALL
OVER SOUTHERN TENNESSEE TODAY. TONIGHT, SOUTHWESTERLY FLOW INCREASES
AHEAD OF THE NEXT TROUGH, AND KICKS THE FRONT BACK TO THE NORTH AS A
WARM FRONT, SETTING THE STAGE FOR WEDNESDAY. FOR THE NIGHT
WORKERS OR ANYONE LOOKING TO CATCH UP ON SLEEP, TODAY IS ANOTHER
GOOD NAPPING DAY. WITH ALL THE MOISTURE HANGING AROUND FROM THE
LAST COUPLE DAYS OF RAIN, PATCHY FOG AND LOW CLOUD CEILINGS WILL
DOMINATE THROUGH TONIGHT, SO DON'T EXPECT TO SEE THE SUN EVEN WITH
A LULL IN RAIN ACTIVITY.
LONG TERM
(WEDNESDAY THROUGH MONDAY)
ISSUED AT 318 AM EST TUE DEC 17 2024
KEY MESSAGES:
1. WARM WITH RAIN AND POSSIBLY A FEW THUNDERSTORMS WEDNESDAY.
2. TURNING COLDER FOR THURSDAY THROUGH MONDAY.
3. MOSTLY DRY FROM THURSDAY THROUGH MONDAY, BUT A FEW SHOWERS/SNOW
SHOWERS/FLURRIES POSSIBLE MAINLY NORTH AND MOUNTAINS FRIDAY INTO
SATURDAY.
DISCUSSION:
WE START THE PERIOD WITH AN UPPER LEVEL SHORT WAVE OVER THE PLAINS
AND A SURFACE COLD FRONT ACROSS WESTERN PORTIONS OF KY AND TN. THIS
SHORT WAVE AND COLD FRONT WILL MOVE EAST AND WILL BRING RAIN TO OUR
AREA WEDNESDAY BEFORE EXITING EARLY WEDNESDAY NIGHT. MODELS INDICATE
SOME WEAK CONVECTIVE ENERGY AVAILABLE WEDNESDAY WITH THE HREF MEAN
MUCAPE VALUES GENERALLY AROUND 100-300 J/KG, SO THERE MAY BE A FEW
EMBEDDED THUNDERSTORMS AS WELL WEDNESDAY AS THE FRONT MOVES THROUGH.
850MB WINDS OF 40+KTS FROM THE SOUTHWEST WILL PROVIDE SOME GUSTY
WINDS ESPECIALLY OVER THE HIGHER ELEVATIONS, WHERE SOME GUSTS OF 30
TO 40 MPH CAN BE EXPECTED DURING THE DAY. IT WILL ALSO BE QUITE
WARM WEDNESDAY, WITH HIGH TEMPERATURES GENERALLY AROUND 15 DEGREES
ABOVE NORMAL.
ONCE THE COLD FRONT EXITS, COLDER AND DRIER AIR WILL BE MOVING IN
WEDNESDAY NIGHT. THURSDAY WILL BE DRY, AND TEMPERATURES WILL BE NEAR
NORMAL FOR THIS TIME OF YEAR.
MODELS SHOW ANOTHER SHORT WAVE MOVING THROUGH THE EASTERN US TROUGH
THAT WILL SWING THROUGH OUR REGION FRIDAY ALONG WITH ANOTHER COLD
FRONT. MOISTURE LOOKS QUITE LIMITED, BUT A FEW SHOWERS/HIGH
ELEVATION SNOW SHOWERS MAY OCCUR FRIDAY MAINLY NORTH AS THE SYSTEM
MOVES THROUGH, AND SOME ADDITIONAL SNOW SHOWERS/FLURRIES CAN BE
EXPECTED MAINLY NORTH AND MOUNTAINS FRIDAY NIGHT INTO SATURDAY
MORNING AS MUCH COLDER AIR MOVES IN. RIGHT NOW ANY SNOW
ACCUMULATIONS LOOK LIGHT OVER THE HIGHER TERRAIN, WITH LATEST
ENSEMBLE PROBABILITIES OF 24 HOUR SNOW ACCUMULATION GTE 1" AROUND 20-
30% IN THESE AREAS. SUNDAY WILL BE DRY AND COLD, AND DRY WEATHER
SHOULD CONTINUE MONDAY WITH SOME MODERATION IN TEMPERATURES CLOSER
TO SEASONAL NORMALS.
AVIATION
(12Z TAFS)
ISSUED AT 644 AM EST TUE DEC 17 2024
LOW CONFIDENCE FORECAST CONTINUES, GOOD PROBABILITIES IN THAT MVFR
OR IFR CONDITIONS PERSIST TODAY IN CEILINGS WITH POOR ACCOMPANYING
VIS, BUT THE BULK OF THE RAIN IS DONE UNTIL WARM FRONT ASSOCIATED
DRIZZLE AFTER 06Z TOMORROW. LIGHT WINDS. A LOW CHANCE FOR VFR
CONDITIONS AT TRI BETWEEN 22Z AND 03Z OR SO, BUT OPTED FOR MORE
PESSIMISTIC APPROACH GIVEN UNCERTAINTY AND PREVAILING WIDESPREAD
WEATHER.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 64 56 68 40 / 60 50 90 20
KNOXVILLE MCGHEE TYSON AIRPORT, TN 62 55 66 38 / 40 60 90 30
OAK RIDGE, TN 61 55 63 37 / 30 70 100 20
TRI CITIES AIRPORT, TN 59 52 64 37 / 40 40 90 60
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
SHORT TERM...WELLINGTON
AVIATION...WELLINGTON
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