578
FXUS64 KMRX 012321
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
621 PM EST SAT FEB 1 2025
..NEW AVIATION
SHORT TERM
(THIS EVENING THROUGH SUNDAY)
ISSUED AT 230 PM EST SAT FEB 1 2025
KEY MESSAGES:
1. DENSE FOG POSSIBLE TONIGHT AND SUNDAY MORNING IN THE SOUTHERN AND
CENTRAL TN VALLEY.
2. MOSTLY SUNNY AND MILD SUNDAY AFTERNOON.
DISCUSSION:
PERSISTENT CLOUD COVER THIS MORNING IS STARTING TO SHOW SIGNS OF
EROSION FROM THE NORTH AS A WEAK COLD FRONT DRIFTS SOUTHWARD. WINDS
HAVE SHIFTED TO NORTH ACROSS MOST OF THE AREA, SO THIS CLEARING
TREND SHOULD CONTINUE THROUGH THE EVENING, WITH COUNTIES AGAINST THE
MOUNTAINS BEING SLOWEST TO CLEAR/SCATTER OUT. MODEL GUIDANCE
(NAMNEST, HRRR, LAMP IS STRONGLY SUGGESTING FOG DEVELOPMENT TONIGHT
IN THE CENTRAL AND SOUTHERN VALLEY WITH VISIBILITY OF A QUARTER
MILE OR LESS FROM KNOXVILLE TO CHATTANOOGA. AT TRI-CITIES, THERE
WILL BE A LITTLE BETTER PRESSURE GRADIENT AND DOWNSLOPE FLOW AS
HIGH PRESSURE OVER THE MID-ATLANTIC EXTENDS SW ALONG THE BLUE
RIDGE. THE FOG FORMATION WILL BE DEPENDENT ON THE MODELS
ACCURATELY DEPICTING THE CURRENT CLOUD COVER CLEARING OUT THIS
EVENING.
ON SUNDAY WE WILL HAVE A GOOD SW UP-VALLEY FLOW AS LOW PRESSURE
TRACKS INTO THE GREAT LAKES AND HIGH PRESSURE CONTINUES TO EXTEND SW
ACROSS THE CAROLINAS AND GEORGIA, WITH A NEARLY ZONAL FLOW THROUGH
THE MID AND UPPER LEVELS. SW WINDS MAY BE GUSTY AT TIMES, UP TO 20
MPH WITH AFTERNOON MIXING AND CHANNELING THROUGH THE VALLEY. THIS
SHOULD WARM TEMPERATURES UP INTO THE UPPER 50S TO MID 60S FOR MOST
LOCATIONS, WHICH IS ABOUT 8-12 DEGREES ABOVE NORMAL FOR THE DATE.
LONG TERM
(SUNDAY NIGHT THROUGH NEXT SATURDAY)
ISSUED AT 230 PM EST SAT FEB 1 2025
KEY MESSAGES:
1. UNSEASONABLY WARM NEXT WEEK, ESPECIALLY MONDAY THROUGH THURSDAY,
WITH HIGHS 15-20 DEGREES ABOVE NORMAL.
2. DRY THROUGH THE FIRST HALF OF NEXT WEEK, WITH RAIN CHANCES
RETURNING WEDNESDAY THROUGH FRIDAY.
DISCUSSION:
FOR MOST OF THE EXTENDED PERIOD, THE UPPER FLOW WILL BE ZONAL ACROSS
THE NATION WITH A FAST WEST TO EAST MOVEMENT OF SHORT-WAVES. A
SERIES OF JET STREAKS MOVING ACROSS THE OHIO AND TENNESSEE VALLEYS
WILL PRODUCE CONVECTION BEGINNING WEDNESDAY THROUGH SATURDAY.
FOR MONDAY AND TUESDAY, MOSTLY DRY. A MOISTURE STARVED FRONTAL
BOUNDARY WILL APPROACH SOUTHWEST VIRGINIA LATE IN THE DAY TUESDAY.
LOW CHANCE OF A SHOWER BUT CONFIDENCE TOO LOW TO INCLUDE IN
THE FORECAST. UNSEASONABLY WARM.
FOR WEDNESDAY THROUGH THURSDAY EVENING, THIS FRONTAL BOUNDARY
BECOMES QUASI-STATIONARY OVER THE AREA. SERIES OF JET STREAKS MOVING
ACROSS THE OHIO AND TENNESSEE VALLEYS WILL INCREASE THE FRONTO-
GENETIC FORCING ALONG THIS BOUNDARY TO PRODUCE PERIODS OF SHOWERS
AND THUNDERSTORMS. ENSEMBLE CAPE OF 500 J/KG WILL PRODUCE EMBEDDED
THUNDERSTORMS. NAEFS SHOWS PWS INCREASING TO 1 TO 2 STANDARD
DEVIATIONS ABOVE NORMAL SO SOME LOCALLY HEAVY RAINS POSSIBLE.
HOWEVER, NBM 24 HOURS PROBABILITIES OF 1 INCH OR MORE OF RAIN IS
ONLY UP TO 40-50 PERCENT ACROSS SOUTHWEST VIRGINIA. AT THIS TIME,
FLOODING POTENTIAL IS LOW BUT NEEDS TO BE WATCHED.
A BREAK IN THE CONVECTION IS POSSIBLE FRIDAY AS THE JET STREAK MOVES
EAST OF THE AREA. CONFIDENCE IS LOW ON THE TIMING OF THESE WAVES.
FOR SATURDAY, ANOTHER JET STREAK INCREASES THE SOUTHERLY BOUNDARY
LAYER FLOW WITH ANOTHER INCREASING CHANCE OF CONVECTION.
AGAIN, OVERALL A VERY MILD PATTERN WITH PERIODS OF RAIN FOR THE
EXTENDED PERIOD.
DAILY RECORD HIGH MAXIMUM TEMPERATURES
DATE CHATTANOOGA KNOXVILLE TRI-CITIES OAK RIDGE
02-02 76(2016) 75(2016) 71(1989) 74(2016)
02-03 75(1986) 74(2020) 74(1989) 71(2020)
02-04 77(1927) 72(1986) 68(1986) 68(1992)
02-05 75(1890) 73(2008) 71(2008) 71(2019)
02-06 70(2019) 73(1986) 68(1991) 70(2008)
02-07 80(2019) 77(2019) 76(2019) 76(2019)
AVIATION
(00Z TAFS)
ISSUED AT 618 PM EST SAT FEB 1 2025
MVFR CEILINGS ARE EXPECTED TO CONTINUE DIMINISHING ACROSS THE AREA
THIS EVENING. ASSUMING MANY OF THESE CLOUDS DIMINISH, THERE IS A
HIGH LIKELIHOOD OF FOG DEVELOPMENT AT CHA AND TYS WITH LOWER
CHANCES AT TRI. AS OF RIGHT NOW, REDUCTIONS TO IFR HAVE BEEN
MAINTAINED, BUT WORSE CONDITIONS ARE DEFINITELY POSSIBLE FOR AT
LEAST A BRIEF TIME. THROUGHOUT THE DAY ON SUNDAY, INCREASING
SOUTHERLY WINDS ARE EXPECTED WITH MOSTLY CLEAR SKIES.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 39 64 43 70 / 0 0 0 0
KNOXVILLE MCGHEE TYSON AIRPORT, TN 35 62 40 68 / 0 0 0 0
OAK RIDGE, TN 35 60 42 66 / 0 0 0 0
TRI CITIES AIRPORT, TN 33 57 36 64 / 0 0 0 0
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
SHORT TERM...DGS
LONG TERM....DH
AVIATION...BW
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